Malaria-related anaemia

Efficacy of artemether-lumefantrine and dihydroartemisinin-piperaquine and prevalence of molecular markers of anti-malarial drug resistance in children in Togo in 2021

BACKGROUND

Artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are the currently recommended first- and second-line therapies for uncomplicated Plasmodium falciparum infections in Togo. This study assessed the efficacy of these combinations, the proportion of Day3-positive patients (D3 +), the proportion of molecular markers associated with P. falciparum resistance to anti-malarial drugs, and the variable performance of HRP2-based malaria rapid diagnostic tests (RDTs).

METHODS

A single arm prospective study evaluating the efficacy of AL and DP was conducted at two sites (Kouvé and Anié) from September 2021 to January 2022. Eligible children were enrolled, randomly assigned to treatment at each site and followed up for 42 days after treatment initiation. The primary endpoint was polymerase chain reaction (PCR) adjusted adequate clinical and parasitological response (ACPR). At day 0, samples were analysed for mutations in the Pfkelch13, Pfcrt, Pfmdr-1, dhfr, dhps, and deletions in the hrp2/hrp3 genes.

RESULTS

A total of 179 and 178 children were included in the AL and DP groups, respectively. After PCR correction, cure rates of patients treated with AL were 97.5% (91.4-99.7) at day 28 in Kouvé and 98.6% (92.4-100) in Anié, whereas 96.4% (CI 95%: 89.1-98.8) and 97.3% (CI 95%: 89.5-99.3) were observed at day 42 in Kouvé and Anié, respectively. The cure rates of patients treated with DP at day 42 were 98.9% (CI 95%: 92.1-99.8) in Kouvé and 100% in Anié. The proportion of patients with parasites on day 3 (D3 +) was 8.5% in AL and 2.6% in DP groups in Anié and 4.3% in AL and 2.1% DP groups in Kouvé. Of the 357 day 0 samples, 99.2% carried the Pfkelch13 wild-type allele. Two isolates carried nonsynonymous mutations not known to be associated with artemisinin partial resistance (ART-R) (A578S and A557S). Most samples carried the Pfcrt wild-type allele (97.2%). The most common Pfmdr-1 allele was the single mutant 184F (75.6%). Among dhfr/dhps mutations, the quintuple mutant haplotype N51I/C59R/S108N + 437G/540E, which is responsible for SP treatment failure in adults and children, was not detected. Single deletions in hrp2 and hrp3 genes were detected in 1/357 (0.3%) and 1/357 (0.3%), respectively. Dual hrp2/hrp3 deletions, which could affect the performances of HRP2-based RDTs, were not observed.

CONCLUSION

The results of this study confirm that the AL and DP treatments are highly effective. The absence of the validated Pfkelch13 mutants in the study areas suggests the absence of ART -R, although a significant proportion of D3 + cases were found. The absence of dhfr/dhps quintuple or sextuple mutants (quintuple + 581G) supports the continued use of SP for IPTp during pregnancy and in combination with amodiaquine for seasonal malaria chemoprevention.

TRIAL REGISTRATION

ACTRN12623000344695.

Infected erythrocytes and plasma proteomics reveal a specific protein signature of severe malaria

Cerebral malaria (CM), the most lethal complication of Plasmodium falciparum severe malaria (SM), remains fatal for 15-25% of affected children despite the availability of treatment. P. falciparum infects and multiplies in erythrocytes, contributing to anemia, parasite sequestration, and inflammation. An unbiased proteomic assessment of infected erythrocytes and plasma samples from 24 Beninese children was performed to study the complex mechanisms underlying CM. A significant down-regulation of proteins from the ubiquitin-proteasome pathway and an up-regulation of the erythroid precursor marker transferrin receptor protein 1 (TFRC) were associated with infected erythrocytes from CM patients. At the plasma level, the samples clustered according to clinical presentation. Significantly, increased levels of the 20S proteasome components were associated with SM. Targeted quantification assays confirmed these findings on a larger cohort (n = 340). These findings suggest that parasites causing CM preferentially infect reticulocytes or erythroblasts and alter their maturation. Importantly, the host plasma proteome serves as a specific signature of SM and presents a remarkable opportunity for developing innovative diagnostic and prognostic biomarkers.

CO-INFECTION WITH MALARIA AND INTESTINAL PARASITES AND ITS ASSOCIATION WITH ANEMIA IN CHILDREN (ZERO TO TEN YEARS OLD) IN TIKO SUBDIVISION, CAMEROON

Concomitant infections with malaria and intestinal parasitic infections may be associated with anemia in children (0-10 yr). This study determined the prevalence of co-infection with malaria and intestinal parasitic infections and determined its association with anemia in children (0-10 yr) in Tiko, Cameroon. A hospital-based cross-sectional study was carried out whereby venous blood and stool samples were collected from 377 febrile children. Blood was used to perform a full blood count. Thick and thin blood films were prepared and stained with Giemsa for malaria parasite diagnosis. The formol ether concentration technique was used to analyze the stools. Pearson's chi-square test, Student's t-test, and other statistical analyses were performed. Of the 377 participants, 139 (36.9%) were positive for malaria, 21 (5.6%) had intestinal helminths, 8 (2%) had co-infection, and 79 (21.0%) were anemic. Malaria and anemia were prevalent among the children and were significantly associated (P = 0.025). There was no statistically significant difference (P > 0.05) among age groups. Girls were more often infected with malaria (69, 37.3%), and boys were more often infected with intestinal parasites (13, 7.0%), but there was no statistical association for both malaria and intestinal parasitic infections (IPIs) for both sexes (P > 0.05). Hookworms, Ascaris lumbricoides, and Trichuris trichiura were the intestinal parasites found in this study. There was a significant association between anemia and parasitic co-infection in children (P = 0.003). Malaria and IPIs are prevalent in the Tiko municipality. They play a great role in anemia especially when there is a co-infection. Public education and awareness campaigns are necessary in this municipality.

Dysfunction of CD169+ macrophages and blockage of erythrocyte maturation as a mechanism of anemia in Plasmodium yoelii infection

Plasmodium parasites cause malaria with disease outcomes ranging from mild illness to deadly complications such as severe malarial anemia (SMA), pulmonary edema, acute renal failure, and cerebral malaria. In young children, SMA often requires blood transfusion and is a major cause of hospitalization. Malaria parasite infection leads to the destruction of infected and noninfected erythrocytes as well as dyserythropoiesis; however, the mechanism of dyserythropoiesis accompanied by splenomegaly is not completely understood. Using Plasmodium yoelii yoelii 17XNL as a model, we show that both a defect in erythroblastic island (EBI) macrophages in supporting red blood cell (RBC) maturation and the destruction of reticulocytes/RBCs by the parasites contribute to SMA and splenomegaly. After malaria parasite infection, the destruction of both infected and noninfected RBCs stimulates extramedullary erythropoiesis in mice. The continuous decline of RBCs stimulates active erythropoiesis and drives the expansion of EBIs in the spleen, contributing to splenomegaly. Phagocytosis of malaria parasites by macrophages in the bone marrow and spleen may alter their functional properties and abilities to support erythropoiesis, including reduced expression of the adherence molecule CD169 and inability to support erythroblast differentiation, particularly RBC maturation in vitro and in vivo. Therefore, macrophage dysfunction is a key mechanism contributing to SMA. Mitigating and/or alleviating the inhibition of RBC maturation may provide a treatment strategy for SMA.

Child anemia in Cambodia: A descriptive analysis of temporal and geospatial trends and logistic regression-based examination of factors associated with anemia in children

Anemia in children remains a public health concern in many resource-limited countries. To better understand child anemia in Cambodia, we examined temporal and geospatial trends of childhood anemia and used logistic regression to analyze its association with individual and household characteristics using data from the Cambodia Demographic and Health Surveys for 2005, 2010, and 2014. The prevalence of childhood anemia decreased from 62.2% in 2005 to 56.6% in 2014. The prevalence of childhood anemia was highest in Pursat (84.3%) for 2005, Kampong Thom (67%) for 2010, and Preah Vihear and Steung Treng (68.6%) for 2014. After adjusting for other variables, factors positively associated with childhood anemia included having a mother who was anemic (adjusted odds ratio (AOR) = 1.77, 95% CI: 1.58-1.97); being male vs. female (AOR = 1.20, 95% CI: 1.07-1.33), underweight (AOR = 1.24, 95% CI: 1.14-1.57), or stunted (AOR = 1.24, 95% CI: 1.09-1.41); or having had a recent episode of fever (AOR = 1.16, 95% CI: 1.03-1.31). Children were less likely to have anemia if they were older than 12 months. They were also less likely to have anemia if they were from a wealthier household (AOR = 0.64; 95% CI: 0.50-0.84) or had taken medications for intestinal parasites (AOR = 0.86; 95% CI: 0.89-0.93). These associations were generally consistent across time and space. Public health interventions and policies to alleviate anemia should be prioritized to address these factors across geospatial divides. Anemia remains highly prevalent among children aged 6-59 months in Cambodia.

Effectiveness and safety of intermittent preventive treatment with dihydroartemisinin-piperaquine or artesunate-amodiaquine for reducing malaria and related morbidities in schoolchildren in Tanzania: a randomised controlled trial

BACKGROUND

In high transmission settings, most school-aged children harbour malaria parasites without showing symptoms, often leading to anaemia and possibly impaired psychomotor and cognitive abilities. We aimed to assess the effectiveness and safety of intermittent preventive treatment for malaria in school-aged children (IPTsc) living in highly endemic areas.

METHODS

We did an open-label randomised controlled trial in seven primary schools in northeastern Tanzania. Schoolchildren aged 5-15 years were individually randomly assigned (1:1:1) to receive dihydroartemisinin-piperaquine, artesunate-amodiaquine, or standard of care (control) using a balanced block design. Drugs were administered by schoolteachers, with supervision from study nurses, at months 0 (baseline), 4, and 8, and were given in line with manufacturer's recommendations with dose based on the child's bodyweight. The primary endpoints were change from baseline in mean haemoglobin concentration at months 12 and 20, and clinical incidence of malaria and prevalence of parasitaemia at months 12 and 20 in the intervention groups versus the control group. The outcome data were collected through longitudinal surveys conducted every 4 months. Data were analysed on the basis of intention to treat (including all randomised participants) and per protocol (comprising children who completed the full 3-day regimen of all three IPTsc treatment rounds as assigned). This study is registered with ClinicalTrials.gov (NCT03640403).

FINDINGS

Of the 1797 children scheduled for clinical screening, 1566 were enrolled and randomly allocated (526 to receive dihydroartemisinin-piperaquine, 527 to receive artesunate-amodiaquine, and 513 to receive standard of care). Due to COVID-19-related school closures, only two schools were visited at month 12 (135 children in the dihydroartemisinin-piperaquine group, 131 in the artesunate-amodiaquine group, and 118 in the control group). At month 12, compared with the control group, the change from baseline in mean haemoglobin concentration was increased by 0·5 g/dL (95% CI 0·2 to 0·8; p<0·0001) in the dihydroartemisinin-piperaquine group and 0·5 g/dL (0·2 to 0·7; p=0·0020) in the artesunate-amodiaquine group in the intention-to-treat analysis (with similar findings in the per protocol analysis). In the same period, in the intention-to-treat analysis, the prevalence of malaria parasitaemia increased from 28·5% (138 of 485 participants) to 33·6% (39 of 116) in the control group, but decreased from 28·0% (139 of 497) to 12·0% (15 of 125) in the dihydroartemisinin-piperaquine group (-21·6 percentage points [95% CI -31·9 to -11·3], p=0·0001 vs control at month 12) and from 24·7% (124 of 502) to 16·0% (20 of 125) in the artesunate-amodiaquine group (-17·6 percentage points [-28·4 to -6·9], p=0·0015). The decrease for artesunate-amodiaquine was larger in the per protocol analysis (-25·3 percentage points [-36·3 to -14·2], p<0·0001). The protective effect of IPTsc against malaria parasitaemia was 64% (95% CI 39 to 79; p<0·0001) for dihydroartemisinin-piperaquine and 52% (23 to 70; p=0·0015) for artesunate-amodiaquine in the intention-to-treat analysis, and was slightly higher on per protocol analysis. The protective effect against clinical malaria at month 12 was 20% (95% CI 9 to 29; p=0·0002) for dihydroartemisinin-piperaquine and 19% (8 to 28; p=0·0004) for artesunate-amodiaquine. No significant differences in any primary outcomes between the intervention and control groups were noted at month 20. Dihydroartemisinin-piperaquine and artesunate-amodiaquine were associated with a small number of mild adverse events, and there were no treatment-related serious adverse events or deaths.

INTERPRETATION

IPTsc with dihydroartemisinin-piperaquine or artesunate-amodiaquine is a safe and effective approach to reducing malaria parasitaemia, clinical malaria, and related morbidities, and is feasible to implement through programmes delivered by schoolteachers.

FUNDING

Flemish Interuniversity Council (VLIRUOS), EU EDCTP2 programme (MaReCa project), and Global Minds 2019.

TRANSLATION

For the Swahili translation of the abstract see Supplementary Materials section.

Prevalence of mutations in the cysteine desulfurase IscS (Pfnfs1) gene in recurrent Plasmodium falciparum infections following artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) treatment in Matayos, Western Kenya

BACKGROUND

Malaria remains a public health concern globally. Resistance to anti-malarial drugs has consistently threatened the gains in controlling the malaria parasites. Currently, artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are the treatment regimens against Plasmodium falciparum infections in many African countries, including Kenya. Recurrent infections have been reported in patients treated with AL or DP, suggesting the possibility of reinfection or parasite recrudescence associated with the development of resistance against the two therapies. The Plasmodium falciparum cysteine desulfurase IscS (Pfnfs1) K65 selection marker has previously been associated with decreased lumefantrine susceptibility. This study evaluated the frequency of the Pfnfs1 K65 resistance marker and associated K65Q resistant allele in recurrent infections collected from P. falciparum-infected individuals living in Matayos, Busia County, in western Kenya.

METHODS

Archived dried blood spots (DBS) of patients with recurrent malaria infection on clinical follow-up days after treatment with either AL or DP were used in the study. After extraction of genomic DNA, PCR amplification and sequencing analysis were employed to determine the frequencies of the Pfnfs1 K65 resistance marker and K65Q mutant allele in the recurrent infections. Plasmodium falciparum msp1 and P. falciparum msp2 genetic markers were used to distinguish recrudescent infections from new infections.

RESULTS

The K65 wild-type allele was detected at a frequency of 41% while the K65Q mutant allele was detected at a frequency of 22% in the recurrent samples. 58% of the samples containing the K65 wild-type allele were AL treated samples and while 42% were DP treated samples. 79% of the samples with the K65Q mutation were AL treated samples and 21% were DP treated samples. The K65 wild-type allele was detected in three recrudescent infections (100%) identified from the AL treated samples. The K65 wild-type allele was detected in two recrudescent DP treated samples (67%) while the K65Q mutant allele was identified in one DP treated (33%) recrudescent sample.

CONCLUSIONS

The data demonstrate a higher frequency of the K65 resistance marker in patients with recurrent infection during the study period. The study underscores the need for consistent monitoring of molecular markers of resistance in regions of high malaria transmission.

Renal control of life-threatening malarial anemia

Iron recycling prevents the development of anemia under homeostatic conditions. Whether iron recycling was co-opted as a defense strategy to prevent the development of anemia in response to infection is unclear. We find that in severe Plasmodium falciparum malaria, the onset of life-threatening anemia is associated with acute kidney injury (AKI), irrespective of parasite load. Using a well-established experimental rodent model of malaria anemia, we identify a transcriptional response that endows renal proximal tubule epithelial cells (RPTECs) with the capacity to store and recycle iron during P. chabaudi chabaudi (Pcc) infection. This response encompasses the induction of ferroportin 1/SLC40A1, which exports iron from RPTECs and counteracts AKI while supporting compensatory erythropoiesis and preventing the onset of life-threatening malarial anemia. Iron recycling by myeloid cells is dispensable to this protective response, suggesting that RPTECs provide an iron-recycling salvage pathway that prevents the pathogenesis of life-threatening malarial anemia.

Factors associated with anemia among children in South and Southeast Asia: a multilevel analysis

BACKGROUND

South and Southeast Asian countries (SSEA) account for the highest burden of anemia globally, nonetheless, progress towards the decline of anemia has almost been stalled. This study aimed to explore the individual and community- level factors associated with childhood anemia across the six selected SSEA countries.

METHODS

Demographic and Health Surveys of SSEA countries (Bangladesh, Cambodia, India, Maldives, Myanmar, and Nepal) conducted between 2011 and 2016 were analyzed. A total of 167,017 children aged 6-59 months were included in the analysis. Multivariable multilevel logistic regression analysis was used to identify independent predictors of anemia.

RESULTS

The combined prevalence of childhood anemia across six SSEA countries was 57.3% (95% CI: 56.9-57.7%). At the individual level, childhood anemia was significantly higher among (1) mothers with anemia compared to non-anemic mothers (Bangladesh: aOR = 1.66, Cambodia: aOR = 1.56, India: aOR = 1.62, Maldives: aOR = 1.44, Myanmar: aOR = 1.59, and Nepal: aOR = 1.71); (2) children with a history of fever in the last two weeks compared to those without a history of fever (Cambodia: aOR = 1.29, India: aOR = 1.03, Myanmar: aOR = 1.08), and; (3) stunted children compared to those who were not (Bangladesh: aOR = 1.33, Cambodia: aOR = 1.42, India: aOR = 1.29, and Nepal: aOR = 1.27). In terms of community-level factors, children with mothers in communities with a high percentage of community maternal anemia had higher odds of childhood anemia in all countries (Bangladesh: aOR = 1.21, Cambodia: aOR = 1.31, India: aOR = 1.72, Maldives: aOR = 1.35, Myanmar: aOR = 1.33, and Nepal: aOR = 1.72).

CONCLUSION

Children with anemic mothers and stunted growth were found vulnerable to developing childhood anemia. Individual and community-level factors identified in this study can be considered to develop effective anemia control and prevention strategies.

Implication of asymptomatic and clinical Plasmodium falciparum infections on biomarkers of iron status among school-aged children in Malawi

Background

Iron status is considered as a continuum from an iron deficiency with anaemia, without anaemia, varying amounts of stored iron to iron overload. The burden of Plasmodium falciparum infections is typically high among school-aged children (SAC). Nonetheless, SAC are often less likely to be covered by malaria interventions, making them a group with an untreated reservoir of parasite transmission. This study aimed to assess the effects of asymptomatic and clinical malaria infections on biochemical markers of iron status among SAC in Malawi.

Methods

Data from the 2015–2016 Malawi Micronutrient Survey (MNS) was used and multivariable logistic regression models using a generalized estimating equation to account for the complex cluster survey design were constructed. Blood samples of 684 children aged 5 to 14 years old were evaluated for clinical and asymptomatic malaria infections. Furthermore, blood samples were used to estimate haemoglobin (Hb), serum ferritin (SF) and, soluble transferrin receptors (sTfR) concentrations.

Results

Of the 684 SAC analysed, approximately 42% had asymptomatic malaria, while 41.0% had clinical malaria. Anaemia (low Hb levels), iron deficiency (low SF concentration), and functional iron deficiency (high sTfR levels) were found in 20%, 5%, and 30% of the children, respectively. School-aged children with asymptomatic malaria had increased odds of being anaemic (adjusted odds ratio [aOR]: 3.71, 95% confidence interval [CI]: 2.29–5.99) and increased levels of sTfR (aOR: 3.00, 95% CI 2.01–4.47). Similarly, SAC with clinical malaria had increased odds of being anaemic (aOR: 3.54, 95% CI 2.19–5.72) and increased levels of sTfR (aOR: 3.02, 95% CI 2.02–4.52).

Conclusions

Both asymptomatic and clinical malaria were independent risk factors for anaemia and functional iron deficiency (FID). The notion that asymptomatic and clinical malaria were associated with both anaemia and FID underscores the need for public health programmers to consider adding mass screening and treatment for malaria to existing school-based health programmes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04297-1.

Microscopic and submicroscopic infection by Plasmodium falciparum: Immunoglobulin M and A profiles as markers of intensity and exposure

Assessment of serological Plasmodium falciparum–specific antibodies in highly endemic areas provides valuable information about malaria status and parasite exposure in the population. Although serological evidence of Plasmodium exposure is commonly determined by Plasmodium-specific immunoglobulin G (IgG) levels; IgM and IgA are likely markers of malaria status that remain relatively unexplored. Previous studies on IgM and IgA responses have been based on their affinity for single antigens with shortage of immune responses analysis against the whole Plasmodium proteome. Here, we provide evidence of how P. falciparum infection triggers the production of specific IgM and IgA in plasma and its relationship with parasite density and changes in hematological parameters. A total of 201 individuals attending a hospital in Breman Asikuma, Ghana, were recruited into this study. Total and P. falciparum–specific IgM, IgA, and IgG were assessed by ELISA and examined in relation to age (0–5, 14–49, and ≥50 age ranges); infection (submicroscopic vs. microscopic malaria); pregnancy and hematological parameters. Well-known IgG response was used as baseline control. P. falciparum–specific IgM and IgA levels increased in the population with the age, similarly to IgG. These data confirm that acquired humoral immunity develops by repeated infections through the years endorsing IgM and IgA as exposure markers in endemic malaria regions. High levels of specific IgA and IgM in children were associated with microscopic malaria and worse prognosis, because most of them showed severe anemia. This new finding shows that IgM and IgA may be used as diagnostic markers in this age group. We also found an extremely high prevalence of submicroscopic malaria (46.27% on average) accompanied by IgM and IgA levels indistinguishable from those of uninfected individuals. These data, together with the observed lack of sensitivity of rapid diagnostic tests (RDTs) compared to PCR, invoke the urgent need to implement diagnostic markers for submicroscopic malaria. Overall, this study opens the potential use of P. falciparum–specific IgM and IgA as new serological markers to predict malaria status in children and parasite exposure in endemic populations. The difficulties in finding markers of submicroscopic malaria are highlighted, emphasizing the need to explore this field in depth.

The magnitude of anemia and preventive practices in mothers with children under five years of age in Dodi Papase, Volta region of Ghana

Background

Socio-demographic factors influence the magnitude of anemia in endemic areas. The purpose of this study is to establish the magnitude of anemia and to determine anemia preventive practices carried out by mothers with children under five years of age in the Kadjebi District of the Volta region of Ghana.

Methods

This purposive sampling study involved women of reproductive age with children less than five years of age from Saint Mary Theresa Hospital and nurses practicing in the pediatric ward of the hospital. A questionnaire and interview guide were administered respectively, and the data collected were analyzed using the Statistical Package for Social Sciences version 21.

Results

A total of 150 participants were studied; among which analysis of anemia was carried out on 129 women whose children had their hemoglobin levels checked and recorded in the laboratory. Hemoglobin levels recorded for these children showed that 85.3% were anemic, even though 93.8% of the mothers had been given iron supplements during their pregnancy. Furthermore, anemia prevention practices comprised whether the child had been given any anti-malaria prophylaxis (98.4% denied), if the child had been dewormed in the last three months (89.9% denied), whether the child was given iron supplements in the last three months (59.7% denied), if the child had been given vitamin supplements in the last three months (24.0% denied).

Conclusion

Most of the children in the study were anemic. Mothers practiced exclusive breastfeeding, iron, and vitamin supplementation, and ensured that children slept under insecticide-treated mosquito nets as a means of preventing malaria.

A single low dose of primaquine is safe and sufficient to reduce transmission of Plasmodium falciparum gametocytes regardless of cytochrome P450 2D6 enzyme activity in Bagamoyo district, Tanzania

Background

Primaquine is a pro-drug and its active metabolite is potent against mature Plasmodium falciparum gametocytes. Primaquine is metabolized by a highly polymorphic cytochrome P450 2D6 (CYP2D6) enzyme. Mutations in the gene encoding this enzyme may lead to impaired primaquine activity. This study assessed if 0.25 mg/kg single-dose primaquine is safe and sufficient to reduce transmission of gametocytes in individuals with no, reduced, or increased CYP2D6 enzyme activity.

Methods

Between June 2019 and January 2020 children aged 1–10 years, attending at Yombo dispensary, Bagamoyo district, with confirmed microcopy-determined uncomplicated P. falciparum malaria were enrolled in the study. The enrolled patients were treated with a standard artemether-lumefantrine regimen plus 0.25 mg/kg single-dose primaquine and followed up for 28 days for clinical and laboratory assessment. Primaquine was administered with the first dose of artemether-lumefantrine. Safety assessment involved direct questioning and recording of the nature and incidence of clinical signs and symptoms, and measurement of haemoglobin (Hb) concentration. Blood samples collected from 100 patients were used for assessment of post-treatment infectiousness on day 7 using mosquito membrane feeding assays. Molecular methods were used to determine CYP2D6 and glucose-6-phosphate dehydrogenase (G6PD) status. The primary outcome was the safety of 0.25 mg/kg single-dose primaquine based on CYP2D6 status.

Results

In total, 157 children [median age 6.4 (Interquartile range 4.0–8.2) years] were recruited, of whom 21.0% (33/157) and 12.7% (20/157) had reduced CYP2D6 and deficient G6PD activity, respectively. Day 3 mean absolute Hb concentration reduction was 1.50 g/dL [95% confidence interval (CI) 1.10–1.90] and 1.51 g/dL (95% CI 1.31–1.71) in reduced and normal CYP2D6 patients, respectively (t = 0.012, p = 0.990). The day 3 mean absolute Hb concentration reduction in G6PD deficient, G6PD normal and heterozygous female was 1.82 g/dL (95% CI 1.32–2.32), 1.48 g/dL (95% CI 1.30–1.67) and 1.47 g/dL (95% CI 0.76–2.18), respectively (F = 0.838, p = 0.435). Sixteen percent (16/98) of the patients each infected at least one mosquito on day 7, and of these, 10.0% (2/20) and 17.9% (14/78) had reduced and normal CYP2D6 enzyme activity, respectively (x² = 0.736, p = 0.513).

Conclusion

Single-dose 0.25 mg/kg primaquine was safe and sufficient for reducing transmission of P. falciparum gametocytes regardless of CYP2D6 or G6PD status.

Trial registration Study registration number: NCT03352843.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04100-1.

Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data

BACKGROUND

Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia.

METHODS

Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7.

RESULTS

A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0-19.7 g/dL) in Africa, 11.6 g/dL (range 5.0-20.0 g/dL) in Asia and 12.3 g/dL (range 6.9-17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39-3.05], p < 0.001).

CONCLUSIONS

In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.

Passive Surveillance of Malaria in Pregnant Women, Non-pregnant Women and Children Under 5 Years of Age in Bannu District, Khyber Pakhtunkhwa Pakistan

Background: Malaria among pregnant women is one of the major causes of maternal and infant mortality and morbidity, especially in high-risk areas. Therefore, our study identified the burden of malaria for pregnant women, non-pregnant women, and children under 5 years of age, and malaria service health facilities in Bannu district, Khyber Pakhtunkhwa, Pakistan.

Methods: A cross-sectional study was conducted. In this survey, 15,650 individuals were surveyed, and 1,283 were malaria-positive detected. The data were collected from 80 different healthcare centers. SPSS version 23 was used for data analysis. ArcGIS version 10.8 was used for study area mapping.

Results: Malaria was detected in 23.3% of children under five, 4.4% of pregnant women, and 72.3% of non-pregnant women, respectively. Moreover, P. falciparum, P. vivax, and mixed infection had a prevalence of 2.1, 96.8, and 1.1%. The most often used and effective medications to treat malaria were chloroquine (29.7%) and primaquine (69.4%).

Conclusion: This study's findings depict that malaria's prevalence in the non-pregnant women's group was high. Additionally, P. vivax infection was found to be more prevalent than other types of malaria infection. Due to the scarcity of healthcare facilities in this endemic region, special attention should be directed to strengthening the malaria surveillance and eradication programs.

The effect of malaria on haemoglobin concentrations: a nationally representative household fixed-effects study of 17,599 children under 5 years of age in Burkina Faso

Background

Although the association between malaria and anaemia is widely studied in patient cohorts, the population-representative causal effects of malaria on anaemia remain unknown. This study estimated the malaria-induced decrease in haemoglobin levels among young children in malaria-endemic Burkina Faso.

Methods

The study was based on pooled individual-level nationally representative health survey data (2010–2011, 2014, 2017–2018) from 17 599 children under 5 years of age. This data was used to estimate the effects of malaria on haemoglobin concentration, controlling for household fixed-effects, age, and sex in a series of regression analyses. The fixed-effects controlled for observed and unobserved confounding on the household level and allowed to determine the impact of malaria infection status on haemoglobin levels and anaemia prevalence. Furthermore, the diagnostic results from microscopy and rapid diagnostic tests were leveraged to provide a quasi-longitudinal perspective of acute and prolonged effects after malaria infection.

Results

The prevalence of both malaria (survey prevalence ranging from 17.4% to 65.2%) and anaemia (survey prevalence ranging from 74% to 88.2%) was very high in the included surveys. Malaria was estimated to significantly reduce haemoglobin levels, with an overall effect of − 7.5 g/dL (95% CI − 8.5, − 6.5). Acute malaria resulted in a − 7.7 g/dL (95% CI − 8.8, − 6.6) decrease in haemoglobin levels. Recent malaria without current parasitaemia decreased haemoglobin concentration by − 7.1 g/dL (95% CI − 8.3, − 5.9). The in-sample predicted prevalence of severe anaemia was 9.4% among malaria positives, but only 2.2% among children without malaria.

Conclusion

Malaria infection has a strong detrimental effect on haemoglobin levels among young children in Burkina Faso. This effect seems to carry over even after acute infection, indicating prolonged haemoglobin reductions even after successful parasite-elimination. The quasi-experimental fixed-effect approach adds a population level perspective to existing clinical evidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03948-z.

Complementary liver and serum protein profile in wild boars infected by the giant liver fluke Fascioloides magna using tandem mass tags quantitative approach

Liver fluke, Fascioloides magna, is an important non-native parasite introduced to Europe, posing a threat to survival of local wildlife populations. The aim of this study was to assess the serum and liver protein profile of control and F. magna infected wild boars, by means of shotgun tandem mass tag - based quantitative high resolution proteomics approach. In serum, 4 differentially abundant proteins were found out of total 1073 identified, while in liver from 3520 identified proteins, 116 were differentially abundant between healthy and F. magna infected wild boars. Pathway analysis revealed that most of the proteins differing in abundance are involved in metabolism, biological oxidations, cellular responses to stimuli, fatty acid metabolism, and others. Validation of proteomic results was performed for paraoxonase-1, ceruloplasmin, glutathione S-transferase and liver enzymes by ELISA and automated assays. Complementary analysis of liver and serum in F. magna infection enabled insight into changes of proteome profile of the host at local and sistemic level. Our findings showed that chronic infection with F. magna is associated with immune response in host, oxidative stress and metabolomic changes in liver. SIGNIFICANCE: Liver fluke infections are recognised as worldwide neglected diseases with considerable veterinary and public health importance. Pathological changes, clinical signs and outcome of F. magna infection are strongly related to the type of final hosts and their different tolerance to infection. In order to gain insight into host-parasite interactions in wild boars, dead-end host for F. magna, we assessed proteomics profile of serum and liver of control animals and those infected with F. magna. Proteomics analysis of serum and liver in parallel showed as advantageous and beneficial, demonstrating protein alterations mainly at local level. Bioinformatics analysis enabled elucidation of molecular pathways associated with F. magna infection. Identification and validation of proteins associated with infection may have added value to current tools for efficient liver fluke control.

Differences in malaria and haematocrit presentation in children living in different settings, North West Region, Cameroon

BACKGROUND

Malaria continues to be a major cause of morbidity and mortality in Cameroon. With all efforts being made to eliminate malaria, it is imperative to describe the epidemiology of the disease in different parts of the country in order to inform control policies. This study aimed to present the differences in the prevalence and intensity of malaria and the anaemic status of children living in different areas of the North West region of Cameroon.

MATERIALS AND METHODS

This study was carried out from April 2016-July 2017. Blood samples were collected from children via finger pricking. Stained thick and thin blood films were examined through microscopy (x100) to detect the presence of parasites and to estimate the geometric mean parasite density (GMPD). Packed cell volume (PCV) values were determined by micro-centrifugation. Data was analysed using SPSS to determine proportions and test for significance levels between these.

RESULTS

Overall prevalence of malaria was 45.3%. Awing and Obang recorded the highest prevalence while Mankon and Nkwen recorded the lowest (p=0.01). The GMPD of infection was highly heterogeneous between the different localities (p=0.03). Age significantly affected the prevalence of malaria (p=0.02). Sex did not affect the prevalence nor the GMPD of malaria infection (p>0.05). Overall mean PCV value was 32.9±3.9. Localities in urban settings recorded the highest mean PCV values compared to those in rural settings (p=0.68). Sex and age did not affect mean PCV values (p>0.05).

CONCLUSION

Malaria still remains a major problem in the North West region of Cameroon. Malaria control interventions should therefore be based on evident spatial and temporal heterogeneity of Plasmodium species in a particular area so as not to waste resources that would only be of limited effectiveness and value to the populations at risk.

Confounding influences of malnutrition and Plasmodium falciparum and Schistosoma haematobium infections on haematological parameters in school children in Muyuka, Cameroon

Background

School-aged children (SAC) are a high-risk demographic group for infectious diseases and malnutrition. The objective of this study was to assess the burden and the effect of Plasmodium falciparum and Schistosoma haematobium infections on the haematological indices in SAC and the confounding influence of malnutrition on the outcomes.

Methods

This cross-sectional study was conducted in SAC 4–14 years old living in Ikata, Bafia and Mile 14-Likoko in Muyuka, Cameroon. Anthropometric measures of malnutrition were obtained and blood samples collected were used for detection of malaria parasites by Giemsa-stained blood films using light microscopy and complete blood count analysis using an automated haematology analyser. Urine samples collected were used to detect micro haematuria with the aid of reagent strips and the eggs of S. haematobium by urine filtration technique. Multiple linear regression model was used to examine influence of independent variables on haematological parameters.

Results

Out of the 606 SAC examined, the prevalence of single infections with Plasmodium or S. haematobium and co-infection with both parasites was 16.2, 16.3 and 8.3%, respectively. Overall, malaria parasite (MP), urogenital schistosomiasis, malnutrition, anaemia, haematuria, microcytosis and thrombocytopenia was prevalent in 24.4, 24.6, 25.9, 74.4, 12.2, 45.4 and 11.1% of SAC, respectively. A significant linear decline (P = 0.023) in prevalence of P. falciparum infection with the severity of stunting was observed. Factors that significantly influenced haematological parameters included haemoglobin: age, stunting and MP; haematocrit: age and MP; white blood cell count: age; red blood cell count; age and MP; lymphocyte counts: stunting; mean cell volume: age; mean cell haemoglobin: age and stunting; mean cell haemoglobin concentration: sex, stunting and red cell distribution width-coefficient of variation: sex, age and stunting.

Conclusions

Malnutrition, Plasmodium and S. haematobium infections are common while anaemia is a severe public health problem in Muyuka, Cameroon. The interaction between haematological parameters with malaria parasites as well as linear growth index was negative and other interactions indicate systemic inflammation. While findings provide contextual intervention targets to ensure the judicious use of the limited resources, there is need for regular monitoring and proper treatment to improve the health of the underserved population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06201-9.

Ocimum gratissimum leaf extract ameliorates phenylhydrazine-induced anaemia and toxicity in Wistar rats

OBJECTIVES

Ocimum gratissimum L. is used in traditional medicine for the treatment of bacterial infections and anaemia. This study was designed to evaluate the effect of O. gratissimum leaf extract on phenylhydrazine (PHZ)-induced anaemia and toxicity in rats.

METHODS

The experimental rats were divided into five groups (A-E) (n=6/sex/group). Each rat in groups B-E was intraperitoneally administered 50 mg/kg of PHZ for two consecutive days. Group A (normal control) did not receive any PHZ, group B (negative control), group C received orally 5 mg/kg ferrous sulphate whereas groups D and E received 200 and 400 mg/kg O. gratissimum leaf extract respectively, for 14 days.

RESULTS

Red blood cell count, packed cell volume, haemoglobin concentration and high-density lipoprotein increased significantly (p<0.05) whereas low-density lipoprotein and very-low-density lipoprotein decreased in extract-treated groups when compared to the negative control. O. gratissimum (400 mg/kg extract) and standard drug (5 mg/kg ferrous sulphate) significantly (p<0.05) reduced the levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase.

CONCLUSIONS

The results of this study indicate that O. gratissimum leaf extract has a restorative effect on the phenylhydrazine-induced metabolic distortions in the blood, liver, and kidney, and therefore could be used therapeutically as an anti-anaemic tonic.

Ocimum gratissimum leaf extract ameliorates phenylhydrazine-induced anaemia and toxicity in Wistar rats

OBJECTIVES

Ocimum gratissimum L. is used in traditional medicine for the treatment of bacterial infections and anaemia. This study was designed to evaluate the effect of O. gratissimum leaf extract on phenylhydrazine (PHZ)-induced anaemia and toxicity in rats.

METHODS

The experimental rats were divided into five groups (A-E) (n=6/sex/group). Each rat in groups B-E was intraperitoneally administered 50 mg/kg of PHZ for two consecutive days. Group A (normal control) did not receive any PHZ, group B (negative control), group C received orally 5 mg/kg ferrous sulphate whereas groups D and E received 200 and 400 mg/kg O. gratissimum leaf extract respectively, for 14 days.

RESULTS

Red blood cell count, packed cell volume, haemoglobin concentration and high-density lipoprotein increased significantly (p<0.05) whereas low-density lipoprotein and very-low-density lipoprotein decreased in extract-treated groups when compared to the negative control. O. gratissimum (400 mg/kg extract) and standard drug (5 mg/kg ferrous sulphate) significantly (p<0.05) reduced the levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase.

CONCLUSIONS

The results of this study indicate that O. gratissimum leaf extract has a restorative effect on the phenylhydrazine-induced metabolic distortions in the blood, liver, and kidney, and therefore could be used therapeutically as an anti-anaemic tonic.

Haematological profile of children with malaria in Sorong, West Papua, Indonesia

Background

Malaria remains a major public health problem in Indonesian Papua, with children under five years of age being the most affected group. Haematological changes, such as cytopenia that occur during malaria infection have been suggested as potential predictors and can aid in the diagnosis of malaria. This study aimed to assess the haematological alterations associated with malaria infection in children presenting with signs and symptoms of malaria.

Methods

A retrospective study was performed by collecting data from the medical records of malaria patients at Sorong Regional General Hospital, Sorong, West Papua, Indonesia, both from outpatient and inpatient clinics, from January 2014 until December 2017. The laboratory profile of children suffering from malaria was evaluated.

Results

One hundred and eighty-two children aged 1 month to 18 years old were enrolled. The subjects were mostly male (112, 61.5%) with a mean age of 6.45 years (SD = 4.3 years). Children below 5 years of age suffered the most from malaria in this study (77, 42.3%). One hundred two subjects (56%) were infected with Plasmodium falciparum. Half of the enrolled subjects (50%) had haemoglobin level (Hb) between 5.1 and 10 gr/dL. A total of 41 children (53.2%) less than 5 years old suffered from P. falciparum infection. In the age group of 5–10 years, there were 34 children (57.6%) who suffered from P. falciparum, and in the age group > 10 years, 27 children (58.7%) suffered from P. falciparum infection. Only 4 subjects (5.2%) in the less than 5 years old age group had mixed malaria infection. Among eight predictors of the haematological profile, there were five predictors that were significantly associated with the diagnostic criteria, namely haemoglobin, haematocrit, leukocytes, platelets and monocytes (p < 0.05). Generally, clinical symptoms are not significantly associated with a malaria diagnosis, and only one variable showed a significant relationship, pale, with a P value of 0.001.

Conclusions

Children with malaria had changes in some haematological markers, with anaemia, low platelet count, white blood count, and lymphocyte count being the most important predictors of malaria infection in the study area. These markers could be used to raise suspicion of malaria in children living in high endemic areas, such as West Papua.

Acquired antibody responses against merozoite surface protein-119 antigen during Plasmodium falciparum and P.vivax infections in South Indian city of Mangaluru

Merozoite surface protein-1 (MSP-1) of malaria parasites has been extensively studied as a malaria vaccine candidate and the antibody response to this protein is an important indicator of protective immunity to malaria. Mangaluru city and its surrounding areas in southwestern India are endemic to malaria with Plasmodium vivax being the most widespread and prevalent species although P. falciparum also frequently infects. However, no information is available on the level of protective immunity in this population. In this regard, a prospective hospital-based study was performed in malarial patients to assess antibody responses against the 19-kDa C-terminal portion of P. vivax and P. falciparum MSP-1 (MSP-119). Serum samples from 51 healthy endemic controls and 267 infected individuals were collected and anti-MSP-119 antibody levels were analyzed by ELISA. The possible association between the antibody responses and morbidity parameters such as malarial anemia and thrombocytopenia was investigated. Among the 267 infected cases, 144 had P. vivax and 123 had P. falciparum infections. Significant levels of anti-MSP-119 antibody were observed both in P. vivax (123/144; 85.4%) and P. falciparum (108/123; 87.9%) infected individuals. In both type of infections, the major antibody isotypes were IgG1 and IgG3. The IgG levels were found to be increased in patients with severe anemia and thrombocytopenia. The antibody levels were also higher in infected individuals who had several previous infections, although antibodies produced during previous infections were short lived. The predominance of cytophilic anti-MSP-119 IgG1 and IgG3 antibodies suggests the possibility of a dual role of Pv MSP-119 and Pf MSP-119 during malarial immunity and pathogenesis.

Impact of iron fortification on anaemia and iron deficiency among pre-school children living in Rural Ghana

Anaemia in young sub-Saharan African children may be due to the double burden of malaria and iron deficiency. Primary analysis of a double-blind, cluster randomized trial of iron containing micronutrient powder supplementation in Ghanaian children aged 6 to 35 months found no difference in malaria risk between intervention and placebo groups. Here, we performed a secondary analysis of the trial data to assess the impact of long-term prophylactic iron fortificant on the risk of iron deficiency and anaemia in trial subjects. This population-based randomized-cluster trial involved 1958 children aged between 6 to 35 months, identified at home and able to eat semi-solid foods. The intervention group (n = 967) received a daily dose containing 12.5 mg elemental iron (as ferrous fumarate), vitamin A (400 μg), ascorbic acid (30 mg) and zinc (5 mg). The placebo group (n = 991) received a similar micronutrient powder but without iron. Micronutrient powder was provided daily to both groups for 5 months. At baseline and endline, health assessment questionnaires were administered and blood samples collected for analysis. The two groups had similar baseline anthropometry, anaemia, iron status, demographic characteristics, and dietary intakes (p > 0.05). Of the 1904 (97.2%) children who remained at the end of the intervention, the intervention group had significantly higher haemoglobin (p = 0.0001) and serum ferritin (p = 0.0002) levels than the placebo group. Soluble transferrin receptor levels were more saturated among children from the iron group compared to non-iron group (p = 0.012). Anaemia status in the iron group improved compared to the placebo group (p = 0.03). Continued long-term routine use of micronutrient powder containing prophylactic iron reduced anaemia, iron deficiency and iron deficiency anaemia among pre-school children living in rural Ghana's malaria endemic area.

Antrocaryon micraster (A. Chev. And Guillaumin) stem bark extract demonstrated anti-malaria action and normalized hematological indices in Plasmodium berghei infested mice in the Rane's test

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is caused by infection with some species of Plasmodium parasite which leads to adverse alterations in physical and hematological features of infected persons and ultimately results in death. Antrocaryon micraster is used to treat malaria in Ghanaian traditional medicine. However, there is no scientific validation of its anti-malaria properties. The plant does not also have any chemical fingerprint or standardization parameters.

AIM OF THE STUDY

This study sought to evaluate the anti-malaria activity of standardized A. micraster stem bark extract (AMSBE) and its effect on mean survival time (MST) and body weight reduction of Plasmodiumberghei infested mice. And to study the effect of treatment of AMSBE on hematological indices of the P. berghei infested mice in order to partly elucidate its anti-malarial mechanism of action.

MATERIALS AND METHODS

Malaria was induced in female ICR mice by infecting them with 0.2 mL of blood (i.p.) containing 1.0 × 10⁷P. berghei-infested RBCs from a donor mouse and leaving them without treatment for 3 days. AMSBE or Lonart (standard control) was then orally administered at 50, 200 and 400 mg/kg or 10 mg/kg once daily for 4 consecutive days. The untreated control received sterile water. Malaria parasitemia reduction, anti-malarial activity, mean change in body weight and MST of the parasitized mice were evaluated. Furthermore, changes in white blood cells (WBCs), red blood cells (RBCs), platelets count, hemoglobin (HGB), hematocrit (HCT) and mean corpuscular volume (MCV) were also determined in the healthy animals before infection as baseline and on days 3, 5 and 8 after infection by employing complete blood count. Standardization of AMSBE was achieved by quantification of its constituents and chemical fingerprint analysis using UHPLC-MS.

RESULTS

Administration of AMSBE, standardized to 41.51% saponins and 234.960 ± 0.026 mg/g of GAE phenolics, produced significant (P < 0.05) reduction of parasitemia development, maximum anti-malaria activity of 46.01% (comparable to 32.53% produced by Lonart) and significantly (P < 0.05) increased body weight and MST of P. berghei infected mice compared to the untreated control. Moreover, there were significant (P > 0.05) elevation in WBCs, RBCs, HGB, HCT and platelets in the parasitized-AMSBE (especially at 400 mg/kg p.o.) treated mice compared to their baseline values. Whereas, the non-treated parasitized control recorded significant reduction (P < 0.05) in all the above-mentioned parameters compared to its baseline values. The UHPLC-MS fingerprint of AMSBE revealed four compounds with their retention times, percentage composition in their chromatograms and m/z of the molecular ions and fragments in the spectra.

CONCLUSIONS

These results show that A. micraster stem bark possessed significant anti-malaria effect and also has the ability to abolish body weight loss, leucopenia, anemia and thrombocytopenia in P. berghei infected mice leading to prolonged life span. The UHPLC-MS fingerprint developed for AMSBE can be used for rapid authentication and standardization of A. micraster specimens and herbal preparations produced from its hydroethanolic stem bark extract to ensure consistent biological activity. The results justify A. micraster's use as anti-malaria agent.

Pathophysiology of Anemia in HIV-Infected Children Exposed to Malaria

Anemia is a common condition in HIV-infected children; however, its pathophysiology and the contribution of frequent causes of anemia such as iron deficiency (ID) and malaria are poorly understood. We carried out an ancillary study on the effect of HIV on anemia as part of a case-control study on risk factors of anemia among Mozambican children aged 1-59 months with documented HIV status. Of them, 390 children were admitted to the hospital with anemia (hemoglobin [Hb] < 11 g/dL), whereas 272 children without anemia (Hb ≥ 11 g/dL) were recruited in the community. We assessed differences by HIV status in the presentation of anemia etiological factors and the effect of HIV infection on the association of each factor with anemia. Among the 99 HIV-infected and 563 uninfected children included, HIV-infected anemic children had an increased risk of undernutrition (P < 0.0001), Epstein-Barr virus infection (P < 0.0001), bacteremia (P = 0.0060), a decreased risk of malaria (P < 0.0001), and a similar risk of ID (P = 0.7371) compared with anemic-uninfected children. HIV-infected children were significantly less likely to have anemia associated with Plasmodium falciparum hyperparasitemia (P = 0.0444) and had a lower prevalence of parasitemia in the bone marrow (BM) (P < 0.0001) than anemic-uninfected children. Levels of BM erythropoiesis and dyserythropoiesis were comparable between groups. These findings suggest that the pathophysiology of anemia among HIV-infected malaria-exposed children is not related to HIV-specific effects. For unclear reasons, HIV-infected children had reduced risk of malaria infection, whereas ID prevalence was comparable in HIV-infected and uninfected children, suggesting that iron supplementation recommendations should not be different in HIV-infected children.

The elusive parasite: comparing macroscopic, immunological, and genomic approaches to identifying malaria in human skeletal remains from Sayala, Egypt (third to sixth centuries AD)

Although malaria is one of the oldest and most widely distributed diseases affecting humans, identifying and characterizing its presence in ancient human remains continue to challenge researchers. We attempted to establish a reliable approach to detecting malaria in human skeletons using multiple avenues of analysis: macroscopic observations, rapid diagnostic tests, and shotgun-capture sequencing techniques, to identify pathological changes, Plasmodium antigens, and Plasmodium DNA, respectively. Bone and tooth samples from ten individuals who displayed skeletal lesions associated with anaemia, from a site in southern Egypt (third to sixth centuries AD), were selected. Plasmodium antigens were detected in five of the ten bone samples, and traces of Plasmodium aDNA were detected in six of the twenty bone and tooth samples. There was relatively good synchronicity between the biomolecular findings, despite not being able to authenticate the results. This study highlights the complexity and limitations in the conclusive identification of the Plasmodium parasite in ancient human skeletons. Limitations regarding antigen and aDNA preservation and the importance of sample selection are at the forefront of the search for malaria in the past. We confirm that, currently, palaeopathological changes such as cribra orbitalia are not enough to be certain of the presence of malaria. While biomolecular methods are likely the best chance for conclusive identification, we were unable to obtain results which correspond to the current authentication criteria of biomolecules. This study represents an important contribution in the refinement of biomolecular techniques used; also, it raises new insight regarding the consistency of combining several approaches in the identification of malaria in past populations.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12520-021-01350-z.

Red blood cell homeostasis in children and adults with and without asymptomatic malaria infection in Burkina Faso

Asymptomatic malaria infections may affect red blood cell (RBC) homeostasis. Reports indicate a role for chronic hemolysis and splenomegaly, however, the underlying processes are incompletely understood. New hematology analysers provide parameters for a more comprehensive analysis of RBC hemostasis. Complete blood counts were analysed in subjects from all age groups (n = 1118) living in a malaria hyperendemic area and cytokines and iron biomarkers were also measured. Subjects were divided into age groups (<2 years, 2–4, 5–14 and ≥15 years old) and clinical categories (smear-negative healthy subjects, asymptomatic malaria and clinical malaria). We found that hemoglobin levels were similar in smear-negative healthy children and asymptomatic malaria children but significantly lower in clinical malaria with a maximum difference of 2.2 g/dl in children <2 years decreasing to 0.1 g/dl in those aged ≥15 years. Delta-He, presenting different hemoglobinization of reticulocytes and RBC, levels were lower in asymptomatic and clinial malaria, indicating a recent effect of malaria on erythropoiesis. Reticulocyte counts and reticulocyte production index (RPI), indicating the erythropoietic capacity of the bone marrow, were higher in young children with malaria compared to smear-negative subjects. A negative correlation between reticulocyte counts and Hb levels was found in asymptomatic malaria (ρ = -0.32, p<0.001) unlike in clinical malaria (ρ = -0.008, p = 0.92). Free-Hb levels, indicating hemolysis, were only higher in clinical malaria. Phagocytozing monocytes, indicating erythophagocytosis, were highest in clinical malaria, followed by asymptomatic malaria and smear-negative subjects. Circulating cytokines and iron biomarkers (hepcidin, ferritin) showed similar patterns. Pro/anti-inflammatory (IL-6/IL-10) ratio was higher in clinical than asymptomatic malaria. Cytokine production capacity of ex-vivo whole blood stimulation with LPS was lower in children with asymptomatic malaria compared to smear-negative healthy children. Bone marrow response can compensate the increased red blood cell loss in asymptomatic malaria, unlike in clinical malaria, possibly because of limited level and length of inflammation.

Trial registration: Prospective diagnostic study: ClinicalTrials.gov identifier: NCT02669823.

Explorative cross-sectional field study: ClinicalTrials.gov identifier: NCT03176719.

Association between haematological parameters and sickle cell genotypes in children with Plasmodium falciparum malaria resident in Kisumu County in Western Kenya

Background

Sickle cell disease (SCD) is a monogenic disorder due to point mutation in the β-globin gene resulting in substitution of Valine for Glutamic acid. The SCD is prevalent in P. falciparum endemic regions such as western Kenya. Carriage of different sickle cell genotypes may influence haematological parameter during malaria. Children resident in malaria holoendemic regions suffer more from malaria-related complications and this is moderated by the presence of the SCD. In the current study, we determined the association between sickle cell genotypes and haematological parameters in children with P. falciparum malaria resident in Kisumu County in Western Kenya.

Methodology

Children (n = 217, aged 1–192 months) with acute febrile condition were recruited at Jaramogi Oginga Odinga Teaching and Referral Hospital. Chi-square (χ2) analysis was used to determine differences between proportions. Differences in haematological parameters were compared across groups using Kruskal Wallis test and between groups using Mann Whitney U test. Multivariate logistic regression analysis controlling for infection status was used to determine the association between sickle cell genotypes and haematological parameters.

Results

Using HbAA as the reference group, multivariate logistic regression analysis revealed that carriage of HbSS was associated with reduced haemoglobin [OR = 0.310, 95% CI = 0.101–0.956, P = 0.041], reduced haematocrit [OR = 0.318, 95% CI = 0.128–0.793, P = 0.014], reduced RBC count [OR = 0.124, 95% CI = 0.045–0.337, P = 0.001], reduced MCHC [OR = 0.325, 95% CI = 0.118–0.892, P = 0.029], increased leucocytosis [OR = 9.283, 95% CI = 3.167–27.210, P = 0.001] and reduced monocytosis [OR = 0.319, 95% CI = 0.123–0.830, P = 0.019]. However, carriage of HbAS was only associated with increased micro-platelets [OR = 3.629, 95% CI = 1.291–8.276, P = 0.012].

Conclusion

Results show that carriage of HbSS in children influence the levels of haemoglobin, haematocrit, RBC, MCHC, WBC and Monocytes. Therefore prior knowledge of HbSS should be considered to improve clinical management of haematological alterations during malaria in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05625-z.

Quantitative absorption imaging of red blood cells to determine physical and mechanical properties

Red blood cells or erythrocytes, constituting 40 to 45 percent of the total volume of human blood are vesicles filled with hemoglobin with a fluid-like lipid bilayer membrane connected to a 2D spectrin network. The shape, volume, hemoglobin mass, and membrane stiffness of RBCs are important characteristics that influence their ability to circulate through the body and transport oxygen to tissues. In this study, we show that a simple two-LED set up in conjunction with standard microscope imaging can accurately determine the physical and mechanical properties of single RBCs. The Beer–Lambert law and undulatory motion dynamics of the membrane have been used to measure the total volume, hemoglobin mass, membrane tension coefficient, and bending modulus of RBCs. We also show that this method is sensitive enough to distinguish between the mechanical properties of RBCs during morphological changes from a typical discocyte to echinocytes and spherocytes. Measured values of the tension coefficient and bending modulus are 1.27 × 10⁻⁶ J m⁻² and 7.09 × 10⁻²⁰ J for discocytes, 4.80 × 10⁻⁶ J m⁻² and 7.70 × 10⁻²⁰ J for echinocytes, and 9.85 × 10⁻⁶ J m⁻² and 9.69 × 10⁻²⁰ J for spherocytes, respectively. This quantitative light absorption imaging reduces the complexity related to the quantitative imaging of the biophysical and mechanical properties of a single RBC that may lead to enhanced yet simplified point of care devices for analyzing blood cells.

The constant thickness in the microfluidic channel is used for controlled absorption of red and blue light to measure red blood cell hemoglobin and height mapping. High speed recording of the height mapping provides us the membrane fluctuation.

Predictors of inpatient mortality among children hospitalized for severe acute malnutrition: a systematic review and meta-analysis

BACKGROUND

Malnutrition underlies 45% of under-5 deaths globally. Severe acute malnutrition (SAM) is the most serious form of undernutrition, characterized by wasting with or without edema. Mortality remains high (10%-40%) among children requiring hospitalization for complicated SAM.

OBJECTIVES

We aimed to systematically document the factors independently associated with inpatient mortality in children with SAM.

METHODS

Embase, Ovid MEDINE, the Cochrane Library, and clinicaltrials.gov were searched for articles published between January 2000 and January 2020, using a prespecified protocol. Eligible studies included children aged ≤59 mo hospitalized with SAM and used multivariable analysis to assess the baseline factors independently associated with inpatient mortality. Random-effects meta-analysis, stratified by the stated measure of effect, was used where >20% of studies included the same factor in analyses.

RESULTS

Twenty-eight of 1432 studies fulfilled inclusion criteria: 19 studies included all children with SAM and 9 included specific subgroups of children with SAM. All 19 main studies were from 8 countries across Africa, with a median of 400 children/study. The mean inpatient mortality was 15.7% (95% CI: 10.4%, 21.0%) and HIV prevalence ranged from 2.1% to 51%. Nine factors were included in the meta-analysis, stratified by HR and OR. HIV infection (HR: 4.32; 95% CI: 2.31, 8.08), weight-for-height z score (WHZ) (OR: 0.44; 95% CI: 0.24, 0.80), diarrhea (HR: 2.84; 95% CI: 1.40, 5.75), pneumonia (HR: 1.89; 95% CI: 1.19, 3.02), presence of shock (HR: 3.67; 95% CI: 2.24, 6.03), and lack of appetite (HR: 2.16; 95% CI: 1.48, 3.16) were associated with increased mortality, whereas child age and sex were not. The association between edema and mortality was difficult to ascertain from the available studies.

CONCLUSIONS

HIV infection, diarrhea, pneumonia, shock, lack of appetite, and lower WHZ are independent predictors of inpatient mortality in children with SAM. These factors may help to risk-stratify children being hospitalized with complicated SAM.This systematic review/meta-analysis protocol was registered at www.crd.york.ac.uk/prospero as CRD42019152267.

A cross-sectional study on risk factors for infection with Parvovirus B19 and the association with anaemia in a febrile paediatric population in Ghana

Parvovirus B19 (B19V) occurs globally and can cause severe anaemia. The role of co-infections with Plasmodium falciparum (P. falciparum) has been controversially discussed. The study aimed to determine prevalence and severity of B19V infection, and the effect of co-infections on the risk for anaemia. Between November 2013 and April 2015 a total of 1186 hospital visits of children with fever admitted to a hospital in Ghana were recorded. Malaria, B19V and additional diagnostics for fever causes were performed. Recent B19V infection was defined as PCR and/or IgM positivity. Risk factors for a B19V infection and for anaemia were analysed. The prevalence of anaemia was compared between children with/without B19V infection, stratified for the presence of malaria. B19V IgM/PCR was positive in 6.4% (n = 76; 40 IgM + , 30 PCR + , 6 IgM + and PCR +). Among the B19V cases 60.5% had a simultaneous P. falciparum infection. B19V IgM positivity but not PCR positivity was associated with moderate-severe anaemia (OR = 2.6; 95%-CI: 1.3-5.3; P < 0.01 vs. OR = 0.9; 95%-CI: 0.4-1.8; P = 0.70). P. falciparum and IgM positive B19V infection were independent risk factors for anaemia with no evidence of effect modification. Our data show a significant association between B19V infection, defined as IgM but not PCR positivity, and moderate-severe anaemia. A multiplicative effect of B19V and P. falciparum infection was not found.

Prevalence and factors associated with anemia among women of reproductive age in seven South and Southeast Asian countries: Evidence from nationally representative surveys

BACKGROUND

Anemia remains a major public health challenge with high prevalence among women in South and Southeast Asian countries. Reductions in anemia rates have been stalled, despite the implementation of different maternal health and nutrition programs. This study aimed to assess the prevalence and factors associated with anemia among women of reproductive age in seven selected South and Southeast Asian countries.

METHODS

This cross-sectional analysis utilized data from the most recent demographic and health surveys from seven selected South and Southeast Asian countries (Bangladesh, Cambodia, India, Maldives, Myanmar, Nepal, and Timor-Leste) between 2011 and 2016. This study included 726,164 women of reproductive age. Multiple logistic regression was performed to assess the factors associated with anemia among women for each country separately.

RESULTS

The combined prevalence of anemia was 52.5%, ranged from 22.7% in Timor-Leste to 63% in the Maldives. Results from multiple logistic regression suggest that likelihood of anemia is significantly higher among younger women (15-24 years), women with primary or no education, women from the poorest wealth quintile, women without toilet facilities and improved water sources, underweight women, and women with more than one children born in last five years in most of the countries.

CONCLUSIONS

The prevalence of anemia is high among women of reproductive age in the seven selected South and Southeast Asian countries. The results of this study suggest that various household, environmental and individual factors contribute to the increased likelihood of anemia. Evidence-based, multidisciplinary policies and programs targeting mothers' health and nutrition status, in addition to scaling-up women's education and socioeconomic status, are warranted to combat anemia.

Impact of malaria on haematological parameters of urban, peri-urban and rural residents in the Ashanti region of Ghana: a cross-sectional study

Background: We aimed at investigating the impact of malaria on the haematological parameters of residents from different demographic settlements in the Ashanti Region of Ghana. Malaria parasites trigger changes in certain haematological parameters, which may result in a number of clinical manifestations. Differences in demographic settlements, such as rural, peri-urban and urban settlements may also influence these changes, but this has not been extensively studied in Ghana. Methods: We conducted a hospital-based, cross-sectional study from January to December 2018 in three different settlements. A total of 598 participants were recruited. Blood smears were examined to detect and quantify malaria parasitaemia, while haematological parameters were measured using a haematology analyser. Results: Participants from the rural settlement had the highest malaria prevalence (21.3%) compared to urban (11.8%) and peri-urban areas (13.3%); however, the peri-urban area had the highest median parasite density (568; IQR=190.0-1312.0). Age was significantly associated with the odds of malaria positivity (OR: 0.97; CI:0.96 - 0.99;  p=4.96*10 -4). When haematological parameters of the malaria-infected study participants were compared to the parameters of uninfected participants, red blood cell count (p=0.017), haemoglobin (p=0.0165), haematocrit (p=0.0015), mean corpuscular volume (p=0.0014), plateletcrit (p<0.0001) and platelet count (p<0.0001) were all significantly lower in the malaria infected group. In addition to age, haemoglobin and plateletcrit levels were also inversely correlated with the odds of testing positive for malaria, suggesting that children who were anaemic and/or thrombocytopaenic were likely to be infected. After fitting the data to a logistic regression model comprising the three variables, the model correctly categorised 78% of uninfected study participants, but only 50% of the malaria-positive participants. Conclusions: Study participants who were positive for malaria were younger and had low haemoglobin and plateletcrit levels compared to uninfected individuals. Further studies are needed to more precisely elucidate the relationship between malaria infection,demographic and haematological parameters.

A MATHEMATICAL STUDY OF THE IMPLICIT ROLE OF INNATE AND ADAPTIVE IMMUNE RESPONSES ON WITHIN-HUMAN PLASMODIUM FALCIPARUM PARASITE LEVELS

A within-human-host malaria parasite model, integrating key variables that influence parasite evolution-progression-advancement, under innate and adaptive immune responses, is analyzed. The implicit role of immunity on the steady state parasite loads and parasitemia reproduction number ([Formula: see text]), a threshold parameter measuring the parasite’s annexing ability of healthy red blood cells (HRBCs), eventually rendering a human infectious to mosquitoes, is investigated. The impact of the type of recruitment function used to model HRBC growth is also investigated. The model steady states and [Formula: see text], both obtained as functions of immune system variables, are analyzed at snapshots of immune sizes. Model results indicate that the more the immune cells, innate and adaptive, the more efficient they are at inhibiting parasite development and progression; consequently, the less severe the malaria disease in a patient. Our analysis also illustrates the existence of a Hopf bifurcation leading to a limit cycle, observable only for the nonlinear recruitment functions, at reasonably large [Formula: see text].

Iron deficiency anaemia among 6-to-36-month children from northern Angola

BACKGROUND

Angola is one of the southern African countries with the highest prevalence of anaemia. Identifying anaemia determinants is an important step for the design of evidence-based control strategies. In this study, we aim at documenting the factors associated with Iron Deficiency Anaemia (IDA) in 948 children recruited at the Health Research Center of Angola study area during 2015.

METHODS

Data on demographic, socio-economic and parental practices regarding water, sanitation, hygiene, malaria infection and infant and young child feeding were collected, as well as parasitological, biochemical and molecular data. Total and age-stratified multivariate multinomial regression models were fitted to estimate the magnitude of associations between anaemia and its determinants.

RESULTS

Anaemia was found in 44.4% of children, of which 46.0% had IDA. Overall, regression models associated IDA with age, gender and inflammation and non-IDA with age, zinc deficiency and overload, P. falciparum infection, sickle cell trait/anaemia. Among 6-to-23-month-old children IDA was associated with continued breastfeeding and among 24-to-36-month-old children IDA was associated with stunting. Furthermore, zinc deficiency was associated with non-IDA among both age groups children. Inflammation was associated with IDA and non-IDA in either 6-to-23 and 24-to-36 months old children.

CONCLUSION

The main variables associated with IDA and non-IDA within this geographic setting were commonly reported in Africa, but not specifically associated with anaemia. Additionally, the associations of anaemia with inflammation, zinc deficiency and infections could be suggesting the occurrence of nutritional immunity and should be further investigated. In age groups, zinc overload was observed to protect under 6 months children from Non-IDA, while continued breastfeeding was associated with increased IDA prevalence in 6-to-23 months children, and stunting was suggested to increase the odds of IDA in 24-to-36 month children. This site-specific aetiology profile provides an essential first set of evidences able to inform the planification of preventive and corrective actions/programs. Nevertheless, regional and country representative data is needed.

Impact of malaria on haematological parameters of urban, peri-urban and rural residents in the Ashanti region of Ghana: a cross-sectional study

Background: We aimed at investigating the impact of malaria on the haematological parameters of residents from different demographic settlements in the Ashanti Region of Ghana. Malaria parasites trigger changes in certain haematological parameters, which may result in a number of clinical manifestations. Differences in demographic settlements, such as rural, peri-urban and urban settlements may also influence these changes, but this has not been extensively studied in Ghana. Methods: We conducted a hospital-based, cross-sectional study from January to December 2018 in three different settlements. A total of 598 participants were recruited. Blood smears were examined to detect and quantify malaria parasitaemia, while haematological parameters were measured using a haematology analyser. Results: Participants from the rural settlement had the highest malaria prevalence (21.3%) compared to the urban (11.8%) and peri-urban areas (13.3%); however, the peri-urban area had the highest median parasite density (568; IQR=190.0-1312.0). Age was significantly associated with the odds of malaria positivity (OR: 0.97; CI:0.96 - 0.99). When haematological parameters of the malaria-infected study participants were compared to the parameters of uninfected participants, red blood cell count (p=0.017), haemoglobin (p=0.0165), haematocrit (p=0.0015), mean corpuscular volume (p=0.0014), plateletcrit (p<0.0001) and platelet count (p<0.0001) were all significantly lower in the malaria infected group. In addition to age, haemoglobin and plateletcrit levels were also inversely correlated with the odds of testing positive for malaria, suggesting that children who were anaemic and/or thrombocytopaenic were likely to be infected. After fitting the data to a logistic regression model comprising the three variables, the model correctly categorised 78% of uninfected study participants, but only 50% of the malaria-positive participants. Conclusions: Study participants who were positive for malaria were younger and had low haemoglobin and plateletcrit levels compared to uninfected individuals. Further studies are needed to more precisely elucidate the relationship between malaria infection,demographic and haematological parameters.

Sickle cell disease and malaria: decreased exposure and asplenia can modulate the risk from Plasmodium falciparum

Background

Patients with sickle cell disease (SCD), an inherited haemoglobinopathy, have increased risk of malaria, at least in part due to impaired splenic function. Infection with Plasmodium falciparum in SCD patients can trigger painful vaso-occlusive crisis, increase the severity of anaemia, and contribute to early childhood mortality.

Case presentation

A 17 year-old Tanzanian male with known SCD was admitted to Muhimbili National Hospital, a tertiary referral centre in Dar-es-Salaam, following an attack of malaria. From 2004 to 2007 the patient had lived in USA, and from 2010 to 2016 in France where, on account of hypersplenism and episodes of splenic sequestrations, in 2014 the spleen was removed. After appropriate clinical and laboratory assessment the patient was re-started on hydroxyurea; and anti-malarial-prophylaxis with proguanil was instituted. The patient has remained well and malaria-free for the following 15 months.

Conclusion

SCD patients are highly vulnerable to malaria infection, and impaired splenic function is a feature of SCD patients, even in those who still anatomically have a spleen. This patient had a surgical splenectomy and, in addition, had probably lost some of the acquired malaria-immunity by having lived for several years in malaria-free areas. This patient is a compelling reminder that long-term anti-malarial prophylaxis should be offered to all patients with SCD who live in malaria-endemic areas.

The risk of morbidity and mortality following recurrent malaria in Papua, Indonesia: a retrospective cohort study

BACKGROUND

An acute episode of malaria can be followed by multiple recurrent episodes either due to re-infection, recrudescence of a partially treated parasite or, in the case of Plasmodium vivax or P. ovale, relapse from the dormant liver stage of the parasite. The aim of this study was to quantify the impact of recurrent malaria episodes on morbidity and mortality in Papua, Indonesia.

METHODS

We undertook a retrospective analysis of routinely collected data from malaria patients attending the primary referral hospital in Papua, Indonesia, between April 2004 and December 2013. Multi-state modelling was used to estimate the effect of recurring malaria episodes on re-presentation and admission to hospital and death. The risks of early (≤ 14 days) and late (15 to 365 days) hospital admission and death were estimated separately in our study to distinguish between the direct and indirect effects of malaria recurrence on adverse outcomes.

RESULTS

A total of 68,361 patients were included in the analysis, of whom 37,168 (54.4%) presented initially with P. falciparum, 22,209 (32.5%) with P. vivax, and 8984 (13.1%) with other species. During 12 months of follow-up after each of the first four malaria episodes, 10,868 (15.9%) patients were admitted to hospital and 897 (1.3%) died. The risk of re-presenting to the hospital with malaria increased from 34.7% (95% CI 34.4%, 35.1%) at first episode to 58.6% (57.5%, 59.6%) following the third episode of malaria. After adjusting for co-factors, infection with P. vivax was a significant risk factor for re-presentation (hazard ratio (HR) = 1.48 (95% CI 1.44, 1.51)) and late admission to hospital (HR = 1.17 (1.11, 1.22)). Patients infected with P. falciparum had a greater overall rate of mortality within 14 days (HR = 1.54 (1.25, 1.92)), but after multiple episodes of malaria, there was a trend towards a higher rate of early death in patients infected with P. vivax compared to P. falciparum (HR = 1.91 (0.73, 4.97)).

CONCLUSIONS

Compared to patients initially infected with P. falciparum, those infected with P. vivax had significantly more re-presentations to hospital with malaria, and this contributed to a high risk of inpatient admission and death. These findings highlight the importance of radical cure of P. vivax to eliminate the dormant liver stages that trigger relapses.

Disparities in the prevalence and risk factors of anaemia among children aged 6–24 months and 25–59 months in Ethiopia

Despite global efforts made to address anaemia, the prevalence remains high in most Sub-Saharan African countries. In Ethiopia, anaemia poses a very strong public health concern. The purpose of the present study was to examine the key risk factors related to anaemia among children aged 6–24 months (younger age group) and 25–59 months (older age group). We used the 2016 Ethiopian Demographic and Health Survey data, collected from 11 023 mothers with under five children. Ordered logistic regression modelling was used for assessing risk factors of childhood anaemia. The results suggest that the prevalence of anaemia was 72 % in the younger and 49 % in the older age groups. The risk factors for anaemia in the younger age group were morbidity (odds ratio (OR) 1⋅77; CI 1⋅21, 2⋅60), having no piped water source (OR 1⋅76; CI 1⋅07, 3⋅01) and no toilet facility (OR 1⋅60; CI 1⋅07, 2⋅38). The key risk factors for anaemia in the older age group were no micronutrient intake (OR 1⋅69; CI 1⋅23, 2⋅31), having a young mother (15–24 years old) (OR 1⋅35; CI 0⋅84, 1⋅91) and a non-working mother (OR 1⋅50; CI 1⋅15, 1⋅96). Anaemia also varied by region, place of residence and economic factors. Multiple factors contributed to the high prevalence of anaemia. Given the structural problem that the country has intervention strategies should consider the unique characteristics of regions and rural residences where the prevalence of anaemia is above the national average.

Release of endothelial activation markers in lungs of patients with malaria-associated acute respiratory distress syndrome

Background

Malaria-associated acute respiratory distress syndrome (MA-ARDS) is an understudied complication of malaria and is characterized by pulmonary inflammation and disruption of the alveolar-capillary membrane. Its pathogenesis remains poorly understood. Since endothelial activation plays an important role in other malarial complications, the expression of two endothelial activation markers, von Willebrand factor (VWF) and angiopoietin-2 (ANG-2), was investigated in the lungs of patients with MA-ARDS.

Methods

Post-mortem lung sections of Plasmodium falciparum-infected patients without alveolar oedema (NA), P. falciparum-infected patients with alveolar oedema (MA-ARDS), and uninfected people who died accidentally with no pathological changes to the lungs (CON) were immunohistochemically stained for VWF and ANG-2, and were evaluated with semi-quantitative analysis.

Results

Alveolar oedematous VWF and ANG-2 and intravascular VWF staining were significantly increased in patients with MA-ARDS versus infected and uninfected control groups. The levels of VWF in the alveolar septa and endothelial lining of large blood vessels of patients with MA-ARDS was significantly decreased compared to controls. ANG-2 expression was increased in the alveolar septa of malaria patients without alveolar oedema versus control patients, while ANG-2⁺ leukocytes were increased in the alveoli in both infected patient groups.

Conclusions

This study documents a high level of VWF and ANG-2, two endothelial activation markers in the oedematous alveoli of post-mortem lung sections of Thai patients with MA-ARDS. Decreased detection of VWF in the endothelial lining of blood vessels, in parallel with an increased presence of intravascular VWF staining suggests marked endothelial activation and Weibel–Palade body release in the lungs of patients with MA-ARDS.

Clinical features and haematological parameters among malaria patients in Mangaluru city area in the southwestern coastal region of India

The aim of this study was to assess the clinical profile, severity and complications of patients suffering from malaria in Mangaluru, a southwestern coastal city in India. A total of 579 patients, who were treated at the District Wenlock Hospital, Mangaluru, and 168 healthy controls were recruited in this study. The clinical profile, haematological and biochemical parameters, and disease complications were assessed. The majority of patients were treated as outpatients and patients who had severe clinical conditions were admitted to the hospital for treatment and supportive care. Among the total 579 patients recruited in this study, the distribution of P. vivax, P. falciparum and mixed infections were 364 (62.9%), 150 (25.9%) and 65 (11.2%), respectively. Among these, 506 (87.4%) had mild malaria, whereas 73 (12.6%) had severe malaria. Overall, the clinical features and severity of malaria in P. vivax and mixed infection patients were comparable to P. falciparum patients, albeit with some significant differences. The clinical complications in severe malaria cases included thrombocytopenia (50.7%), metabolic acidosis (30.1%), severe anaemia (26.0%), jaundice (21.9%), hepatic dysfunction (15.1%), acute renal failure (6.8%), haematuria (8.2%), hypotension (9.6%), cerebral malaria (1.4%) and acute respiratory distress syndrome (1.4%). All the patients with severe malaria recruited in our study were successfully treated and discharged. Majority of patients had mild malaria, likely due to seeking treatment soon after experiencing symptoms and/or having preexisting immune protection. However, a significant number of patients had severe malaria and required hospital admission indicating that there is a substantial need for creating awareness among vulnerable immigrant population. Implementing effective surveillance and vector control measures in malaria hotspot locations in the city and educating people about preventive measures are likely to reduce the malaria burden in this endemic region.

Naturally Acquired Antibody Response to Malaria Transmission Blocking Vaccine Candidate Pvs230 Domain 1

Plasmodium vivax malaria incidence has increased in Latin America and Asia and is responsible for nearly 74.1% of malaria cases in Latin America. Immune responses to P. vivax are less well characterized than those to P. falciparum, partly because P. vivax is more difficult to cultivate in the laboratory. While antibodies are known to play an important role in P. vivax disease control, few studies have evaluated responses to P. vivax sexual stage antigens. We collected sera or plasma samples from P. vivax-infected subjects from Brazil (n = 70) and Cambodia (n = 79) to assess antibody responses to domain 1 of the gametocyte/gamete stage protein Pvs230 (Pvs230D1M). We found that 27.1% (19/70) and 26.6% (21/79) of subjects from Brazil and Cambodia, respectively, presented with detectable antibody responses to Pvs230D1M antigen. The most frequent subclasses elicited in response to Pvs230D1M were IgG1 and IgG3. Although age did not correlate significantly with Pvs230D1M antibody levels overall, we observed significant differences between age strata. Hemoglobin concentration inversely correlated with Pvs230D1M antibody levels in Brazil, but not in Cambodia. Additionally, we analyzed the antibody response against Pfs230D1M, the P. falciparum ortholog of Pvs230D1M. We detected antibodies to Pfs230D1M in 7.2 and 16.5% of Brazilian and Cambodian P. vivax-infected subjects. Depletion of Pvs230D1M IgG did not impair the response to Pfs230D1M, suggesting pre-exposure to P. falciparum, or co-infection. We also analyzed IgG responses to sporozoite protein PvCSP (11.4 and 41.8% in Brazil and Cambodia, respectively) and to merozoite protein PvDBP-RII (67.1 and 48.1% in Brazil and Cambodia, respectively), whose titers also inversely correlated with hemoglobin concentration only in Brazil. These data establish patterns of seroreactivity to sexual stage Pvs230D1M and show similar antibody responses among P. vivax-infected subjects from regions of differing transmission intensity in Brazil and Cambodia.

Relative Contributions of Malaria, Inflammation, and Deficiencies of Iron and Vitamin A to the Burden of Anemia during Low and High Malaria Seasons in Rural Zambian Children

OBJECTIVE

To estimate the burden of anemia attributable to malaria, inflammation, and deficiency of iron or vitamin A during low and high malaria seasons among Zambian children.

STUDY DESIGN

From a cohort of children (n = 820), 4-8 years of age participating in a randomized controlled trial of pro-vitamin A, we estimated attributable fractions for anemia (hemoglobin of <110 or 115 g/L, by age) owing to current malaria or inflammation (C-reactive protein of >5 mg/L, or α-1 acid glycoprotein of >1 g/L, or both), and current or prior iron deficiency (ID; defined as low ferritin [<12 or 15 μg/L for age <5 or >5 years] or functional ID [soluble transferrin receptor of >8.3 mg/L] or both) and vitamin A deficiency (retinol of <0.7 μmol/L), during low and high malaria seasons, using multivariate logistic regression. Serum ferritin, soluble transferrin receptor, and retinol were adjusted for inflammation.

RESULTS

The burden of anemia independently associated with current malaria, inflammation, ID, and vitamin A deficiency in the low malaria season were 12% (P < .001), 6% (P = .005), 14% (P = .001), and 2% (P = .07), respectively, and 32% (P < .001), 15% (P < .001), 10% (P = .06), and 2% (P = .06), respectively, in the high malaria season. In both seasons, functional ID was independently associated with more anemia (approximately 11%) than low ferritin (approximately 4%). Anemia and ID in the low malaria season, accounted for 20% (P < .001) and 4% (P = .095) of the anemia in the subsequent high malaria season.

CONCLUSIONS

Anemia in this population is strongly linked to malaria, inflammation, and functional ID, and to a lesser extent, low iron stores. Integrated control strategies are needed.

Loss of complement regulatory proteins on red blood cells in mild malarial anaemia and in Plasmodium falciparum induced blood-stage infection

Background

Anaemia is a major consequence of malaria, caused by the removal of both infected and uninfected red blood cells (RBCs) from the circulation. Complement activation and reduced expression of complement regulatory proteins (CRPs) on RBCs are an important pathogenic mechanism in severe malarial anaemia in both Plasmodium falciparum and Plasmodium vivax infection. However, little is known about loss of CRPs on RBCs during mild malarial anaemia and in low-density infection.

Methods

The expression of CRP CR1, CD55, CD59, and the phagocytic regulator CD47, on uninfected normocytes and reticulocytes were assessed in individuals from two study populations: (1) P. falciparum and P. vivax-infected patients from a low transmission setting in Sabah, Malaysia; and, (2) malaria-naïve volunteers undergoing P. falciparum induced blood-stage malaria (IBSM). For clinical infections, individuals were categorized into anaemia severity categories based on haemoglobin levels. For IBSM, associations between CRPs and haemoglobin level were investigated.

Results

CRP expression on RBC was lower in Malaysian individuals with P. falciparum and P. vivax mild malarial anaemia compared to healthy controls. CRP expression was also reduced on RBCs from volunteers during IBSM. Reduction occurred on normocytes and reticulocytes. However, there was no significant association between reduced CRPs and haemoglobin during IBSM.

Conclusions

Removal of CRPs occurs on both RBCs and reticulocytes during Plasmodium infection even in mild malarial anaemia and at low levels of parasitaemia.

Association between inflammatory cytokine levels and anemia during Plasmodium falciparum and Plasmodium vivax infections in Mangaluru: A Southwestern Coastal Region of India

Background and Objectives:

Dysregulated production of inflammatory cytokines might play important role in anemia during malaria infection. The objective of this study was to assess the extent of anemia due to malaria, associated complications, and inflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin [IL]-6, and IL-10) across varying anemic intensity during malaria infections.

Materials and Methods:

A hospital-based cross-sectional study was conducted at District Wenlock hospital in Mangaluru city. Samples from 627 patients and 168 healthy controls (HC) were analyzed for level of hemoglobin (Hb), red blood cells (RBCs), and inflammatory cytokines. The blood cell parameters and inflammatory cytokines levels across varying intensity of anemia were analyzed using Kruskal–Wallis test and pair-wise comparison between two groups were by Mann–Whitney U-test. Correlations were calculated by Pearson's and Spearman rank correlations.

Results:

Compared to HC, Hb, and RBC levels were significantly lower in infected patients. On comparison with mild anemia patients (Hb 8–10.9 g/dL), the levels of TNF-α and IL-6 were significantly elevated, whereas IL-10 levels were lower during severe anemia (SA) (Hb <5 g/dL). In this endemic setting, we found a strong negative association between Hb levels and parasitemia, Hb and TNF-α, and positive relationship with IL-10; anemic patients also had significantly high TNF-α/IL-10 ratios. SA was associated with complications such as acute renal failure (16.0%), jaundice (16.0%), metabolic acidosis (24.0%), hypoglycemia (12.0%), hyperparasitemia (4.0%), and hepatic dysfunction (16.0%).

Conclusions:

Contrary to its benign reputation, Plasmodium vivax (Pv) infections can also result in severe malarial anemia (SMA) and its associated severe complications similar to Plasmodium falciparum infections. Dysregulated inflammatory cytokine responses play an important role in the pathogenesis of SMA, especially during Pv infections.

Clinical illness and outcomes in Nigerian children with persistent early-appearing anaemia following initiation of artemisinin-based combination treatments of uncomplicated falciparum malaria

In non-anaemic children with malaria, early-appearing anaemia (EAA) is common following artemisinin-based combination treatments (ACTs) and it may become persistent (PEAA). The factors contributing to and kinetics of resolution of the deficit in haematocrit from baseline (DIHFB) characteristic of ACTs-related PEAA were evaluated in 540 consecutive children with malaria treated with artemether-lumefantrine, artesunate-amodiaquine or dihydroartemisinin-piperaquine. Asymptomatic PEAA occurred in 62 children. In a multiple logistic regression model, a duration of illness ≤3 days before presentation, haematocrit <35% before and <25% one day after treatment initiation, drug attributable fall in haematocrit ≥6%, and treatment with dihydroartemisinin-piperaquine independently predicted PEAA. Overall, mean DIHFB was 5.7% (95% CI 4.8–6.6) 7 days after treatment initiation and was similar for all treatments. Time to 90% reduction in DIHFB was significantly longer in artemether-lumefantrine-treated children compared with other treatments. In a one compartment model, declines in DIHFB were monoexponential with overall mean estimated half-time of 3.9 days (95% CI 2.6–5.1), Cmax of 7.6% (95% CI 6.7–8.4), and Vd of 0.17 L/kg (95% CI 0.04–0.95). In Bland-Altman analyses, overall mean anaemia recovery time (AnRT) of 17.4 days (95% CI 15.5–19.4) showed insignificant bias with 4, 5 or 6 multiples of half-time of DIHFB. Ten children after recovery from PEAA progressed to late-appearing anaemia (LAA). Progression was associated with female gender and artesunate-amodiaquine treatment. Asymptomatic PEAA is common following ACTs. PEAA or its progression to LAA may have implications for case and community management of anaemia and for anaemia control efforts in sub-Saharan Africa where ACTs have become first-line antimalarials.

Trial registration: Pan Africa Clinical Trial Registration PACTR201709002064150, 1 March 2017 http://www.pactr.org

Impact of malaria on haematological parameters of urban, peri-urban and rural patients in the Ashanti region of Ghana: a cross-sectional study

Background: This study aimed at investigating haematological changes in malaria patients across different demographic settlements. Malaria parasites trigger changes in certain haematological parameters, which may result in a number of clinical manifestations. Differences in demographic settlements, such as rural, peri-urban and urban settlements, may also influence these changes, but this has rarely been studied. Methods: We conducted a hospital-based, cross-sectional study from January to December 2018 in three different settlements. A total of 598 participants were recruited. Giemsa-stained blood smears were examined to detect and quantify malaria parasitaemia, while haematological parameters were measured using a haematology analyser. Results: The rural settlement had the highest malaria prevalence compared to the other study communities (p=0.009). The difference in parasite densities across the three communities was also significant (p=0.0149). When the malaria-infected population was compared to the uninfected, there were differences in red blood cell count (p=0.0170), haemoglobin levels (p=0.0165), mean corpuscular volume (p=0.0139) and platelet counts (p<0.0001). The difference in median white blood cell (p-value <0.0001), neutrophil (p-value <0.0001) and lymphocyte (p-value <0.0269) count were significantly higher in infected patients from the peri-urban area compared to malaria patients from the rural and urban areas. There were also significant differences in platelet ( p=0.0002), plateletcrit ( p=0.0041), mean platelet volume ( p=0.0009) and platelet large cell ratio ( p=0.0046) levels between patients from the urban, peri-urban and rural areas. Conclusions: Patients infected with malaria generally had low red blood cell, haemoglobin and platelets in comparison to uninfected patients. There were also significant differences in several haematological parameters between malaria-infected patients from the three demographic settlements. Atypical results from routine haematological assays, especially findings of anaemia and thrombocytopenia, may be indicative of malaria and, in cases where the infection is asymptomatic, may improve diagnosis by prompting a more thorough search for the parasite in the peripheral circulation.

The extent, nature, and pathogenic consequences of helminth polyparasitism in humans: A meta-analysis

Background

Individual helminth infections are ubiquitous in the tropics; geographical overlaps in endemicity and epidemiological reports suggest areas endemic for multiple helminthiases are also burdened with high prevalences of intestinal protozoan infections, malaria, tuberculosis (TB), and human immunodeficiency virus (HIV). Despite this, pathogens tend to be studied in isolation, and there remains a need for a better understanding of the community ecology and health consequences of helminth polyparasitism to inform the design of effective parasite control programs.

Methodology

We performed meta-analyses to (i) evaluate the commonality of polyparasitism for helminth-helminth, helminth-intestinal protozoa, helminth-malaria, helminth-TB, and helminth-HIV co-infections, (ii) assess the potential for interspecies interactions among helminth-helminth and helminth-intestinal protozoan infections, and (iii) determine the presence and magnitude of association between specific parasite pairs. Additionally, we conducted a review of reported health consequences of multiply-infected individuals compared to singly- or not multiply-infected individuals.

Principal findings

We found that helminth-helminth and helminth-intestinal protozoan multiple infections were significantly more common than single infections, while individuals with malaria, TB, and HIV were more likely to be singly-infected with these infections than co-infected with at least one helminth. Most observed species density distributions significantly differed from the expected distributions, suggesting the potential presence of interspecies interactions. All significant associations between parasite pairs were positive in direction, irrespective of the combination of pathogens. Polyparasitized individuals largely exhibited lower hemoglobin levels and higher anemia prevalence, while the differences in growth-related variables were mostly statistically insignificant.

Conclusions

Our findings confirm that helminth polyparasitism and co-infection with major diseases is common in the tropics. A multitude of factors acting at various hierarchical levels, such as interspecies interactions at the within-host infra-parasite community level and environmental variables at the higher host community level, could explain the observed positive associations between pathogens; there remains a need to develop new frameworks which can consider these multilevel factors to better understand the processes structuring parasite communities to accomplish their control.

Helminth infections are a highly prevalent global health problem. These parasitic worm infections occur in areas also burdened with intestinal protozoan infections, malaria, tuberculosis, and human immunodeficiency virus. While these pathogens tend to be studied in isolation, there remains a need to better understand the nature, extent, and health consequences of helminth polyparasitism and co-infection with major diseases. Here, we reviewed the literature and performed meta-analyses to evaluate the commonality of helminth polyparasitism and co-infection, the potential for interspecies interactions between parasites, the association between parasite pairs, and the health consequences among multiply-infected individuals. We confirmed that polyparasitism and co-infection with major diseases are common in the global South and found that multiply-infected individuals experienced worse health consequences when compared to singly or not-multiply infected individuals. Our analysis suggested the potential presence of interspecies interactions and we identified the existence of positive associations between parasite pairs. These findings support the call for integrating deworming into malaria, TB, and HIV treatment protocols and suggest there remains a need to improve our understanding of the factors influencing co-transmission to achieve sustainable parasite control.