Sub-microscopic Plasmodium falciparum infections in matched peripheral, placental and umbilical cord blood samples from asymptomatic Congolese women at delivery

Placental malaria and adverse pregnancy outcomes in Majang Zone of Gambella Region, Southwest Ethiopia: a histopathological and molecular study

BACKGROUND

Placental malaria (PM) is characterized by Plasmodium parasite sequestration in the placenta. It is responsible for various adverse pregnancy outcomes, including maternal anaemia and low birth weight (LBW). This study aimed to assess prevalence and risk factors of PM, and gestational malaria (GM), together with the prevalence of congenital malaria (CM), maternal anaemia, and LBW among parturient women attending delivery ward of Metti Health Centre (Metti HC) in Majang Zone of Gambella Region, Southwest Ethiopia.

METHODS

A cross-sectional study involving 180 parturient women attending delivery ward of Metti HC was conducted from November 2022-March 2023. Sociodemographic, obstetric, and anti-malarial intervention data were collected. Capillary, placental and cord blood, and placental biopsy were collected to diagnose malaria using rapid diagnostic test (RDT), microscopy, quantitative polymerase chain reaction (qPCR), and histopathology. Haemoglobin concentration and blood group of the mother and weight of the newborn were determined. Statistical analyses were done by SPSS Version 26.0. Multivariable logistic regression analysis and Chi-square test were done to identify risk factors. Results were presented in text, tables and graphs.

RESULTS

The prevalence of GM, PM, CM, maternal anaemia, and LBW was 24.4% (95% CI 18.1-30.1), 34.4% (95% CI 27.4-41.4), 5.0% (95% CI 2.4-8.8), 41.7% (95% CI 34.6-49.0) and 27.8% (95% CI 21.6-34.6), respectively. Risk factors of GM were: presence of malaria history within the previous year (AOR: 5.10; 95% CI 1.64-15.83), lack of indoor residual spray (IRS) within the previous year (AOR: 2.98; 95% CI 1.05-8.45), and lack of antenatal care (ANC) contact during the index pregnancy (AOR: 3.96; 95% CI 1.44-10.87). Risk factors of PM were: presence of malaria history within the previous year (AOR: 2.98; 95% CI 1.05-8.45), and lack of ANC contact during the index pregnancy (AOR: 4.83; 95% CI 1.91-12.18). The risk of CM (p < 0.001), maternal anaemia (p < 0.001) and LBW (p < 0.001) increased with GM and PM.

CONCLUSION

There is high prevalence of GM, PM, maternal anaemia, and LBW in the study area. The presence of GM and PM increased the risk of maternal anaemia, CM, and LBW. The identified risk factors should be considered to mitigate malaria among parturient women and its adverse outcomes.

Leger R, Sinkins SP, Diabate A. Wolbachia confers protection against the entomopathogenic fungus Metarhizium pingshaense in African Aedes aegypti

Symbiotic and pathogenic microorganisms such as bacteria and fungi represent promising alternatives to chemical insecticides to respond to the rapid increase of insecticide resistance and vector-borne disease outbreaks. This study investigated the interaction of two strains of Wolbachia, wAlbB and wAu, with the natural entomopathogenic fungi from Burkina Faso Metarhizium pingshaense, known to be lethal against Anopheles mosquitoes. In addition to showing the potential of Metarhizium against African Aedes aegypti wild-type populations, our study shows that the wAlbB and wAu provide a protective advantage against entomopathogenic fungal infections. Compared to controls, fungal-infected wAu and wAlbB-carrying mosquitoes showed higher longevity, without any significant impact on fecundity and fertility phenotypes. This study provides new insights into the complex multipartite interaction among the mosquito host, the Wolbachia endosymbiont and the entomopathogenic fungus that might be employed to control mosquito populations. Future research should investigate the fitness costs of Wolbachia, as well as its spread and prevalence within mosquito populations. Additionally, evaluating the impact of Wolbachia on interventions involving Metarhizium pingshaense through laboratory and semi-field population studies will provide valuable insights into the effectiveness of this combined approach.

Uptake of intermittent preventive treatment of malaria in pregnancy and risk factors for maternal anaemia and low birthweight among HIV-negative mothers in Dschang, West region of Cameroon: a cross sectional study

BACKGROUND

Approximately 32 million pregnant women are at risk of malaria with up to 10,000 maternal deaths and 200,000 neonates at risk annually. Intermittent Preventive Treatment (IPT) with sulfadoxine-pyrimethamine (SP) is recommended by the World Health Organization (WHO) to reduce disease in pregnancy and adverse maternal and newborn outcomes. At least three doses of SP should be taken by pregnant women during antenatal consultation (ANC) beginning from the thirteenth week of pregnancy till parturition. The aim of this study was to assess uptake of IPT during pregnancy and risk factors for maternal anaemia and infant birth weight in Dschang, West region of Cameroon.

METHODS

A total of 380 consenting pregnant women at delivery were recruited in a cross- sectional prospective survey between January to December 2021. Data on ANC attendance, total dose of IPT and history of malaria were abstracted from hospital ANC records while socio-demographic characteristics, bed net use and obstetrics history of each participant were also recorded through an interview. Further, blood samples were collected from the intervillous space for assessment of maternal anaemia and microscopic parasitology. Nested PCR based on amplification of the Plasmodium 18S sRNA was carried out to detect submicroscopic infection. IPTp coverage was calculated per WHO recommendation and the prevalence of anaemia and low birth weight were estimated as proportions in the total sample of pregnant women and live births, respectively. Crude and adjusted odds ratios and their 95% confidence intervals were used to estimate associations between pregnancy outcomes considered and risk factors in specific and general models. A p < 0.05 was considered significant. The R software (V4.1.4) was used for all analyses.

RESULTS

A majority of pregnant women was aged between 24 and 34 years old (59.2%) and had secondary education (58.8%). Uptake of ≥ 3 IPTp was 64.99% with 77.20% of all who received at least one IPTp doses taking a mix of SP and DP or DP alone in successive ANC contacts. Those with four or more ANC contacts (73.42%) were more likely to have received at least one IPTp. Furthermore, 13.9% of live births had low birthweights (BW < 2500 g) and one in four parturient women with moderate anaemia by WHO criteria. Microscopy (blood smear examination) and PCR-based diagnosis revealed between 0% and 1.57% of parasite-infected placental samples, respectively. Reported malaria in pregnancy predicted maternal anaemia at birth but not birth weight. Only gestational age (< 37 weeks) and bed net use (< 5 months) significantly predicted infant birth weight at delivery.

CONCLUSION

The uptake of WHO recommended IPT doses during pregnancy was moderately high. Reported malaria in pregnancy, poor bed net coverage, gestational age less than 37 weeks adversely affect maternal haemoglobin levels at birth and infant birth weight. Asymptomatic and submicroscopic placental parasite infections was found at low prevalence. Together these results highlight the importance of maintaining aggressive measures to prevent malaria in pregnancy and protect the health of mother and baby.

Screening for Resistant Bacteria, Antimicrobial Resistance Genes, Sexually Transmitted Infections and Schistosoma spp. in Tissue Samples from Predominantly Vaginally Delivered Placentae in Ivory Coast and Ghana

Medical complications during pregnancy have been frequently reported from Western Africa with a particular importance of infectious complications. Placental tissue can either become the target of infectious agents itself, such as, e.g., in the case of urogenital schistosomiasis, or be subjected to contamination with colonizing or infection-associated microorganisms of the cervix or the vagina during vaginal delivery. In the retrospective cross-sectional assessment presented here, the quantitative dimension of infection or colonization with selected resistant or pathogenic bacteria and parasites was regionally assessed. To do so, 274 collected placental tissues from Ivory Coastal and Ghanaian women were subjected to selective growth of resistant bacteria, as well as to molecular screening for beta-lactamase genes, Schistosoma spp. and selected bacterial causative agents of sexually transmitted infections (STI). Panton-Valentine-negative methicillin-resistant Staphylococcus aureus (MRSA) was grown from 1.8% of the tissue samples, comprising the spa types t008 and t688, as well as the newly detected ones, t12101 (n = 2) and t12102. While the culture-based recovery of resistant Enterobacterales and nonfermentative rod-shaped Gram-negative bacteria failed, molecular assessments confirmed beta-lactamase genes in 31.0% of the samples with multiple detections of up to four resistance genes per sample and blaCTX-M, blaIMP, blaGES, blaVIM, blaOXA-58-like, blaNDM, blaOXA-23-like, blaOXA-48-like and blaKPC occurring in descending order of frequency. The beta-lactamase genes blaOXA-40/24-like, blaNMC_A/IMI, blaBIC, blaSME, blaGIM and blaDIM were not detected. DNA of the urogenital schistosomiasis-associated Schistosoma haematobium complex was recorded in 18.6% of the samples, but only a single positive signal for S. mansoni with a high cycle-threshold value in real-time PCR was found. Of note, higher rates of schistosomiasis were observed in Ghana (54.9% vs. 10.3% in Ivory Coast) and Cesarean section was much more frequent in schistosomiasis patients (61.9% vs. 14.8% in women without Schistosoma spp. DNA in the placenta). Nucleic acid sequences of nonlymphogranuloma-venereum-associated Chlamydia trachomatis and of Neisseria gonorrhoeae were recorded in 1.1% and 1.9% of the samples, respectively, while molecular attempts to diagnose Treponema pallidum and Mycoplasma genitalium did not lead to positive results. Molecular detection of Schistosoma spp. or STI-associated pathogens was only exceptionally associated with multiple resistance gene detections in the same sample, suggesting epidemiological distinctness. In conclusion, the assessment confirmed considerable prevalence of urogenital schistosomiasis and resistant bacterial colonization, as well as a regionally expected abundance of STI-associated pathogens. Continuous screening offers seem advisable to minimize the risks for the pregnant women and their newborns.

Prevalence of non-Plasmodium falciparum species in southern districts of Brazzaville in The Republic of the Congo

BACKGROUND

Although Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these require more attention in Africa. Information on the epidemiological situation of non-P. falciparum species infections is scarce in many countries, including in the Democratic Republic of the Congo (hereafter Republic of the Congo) where malaria is highly endemic. The aim of this study was to determine the prevalence and distribution of non-P. falciparum species infections in the region south of Brazzaville.

METHODS

A cross-sectional survey was conducted in volunteers living in rural and urban settings during the dry and rainy seasons in 2021. Socio-demographic and clinical parameters were recorded. Plasmodium infection in blood samples was detected by microscopic analysis and nested PCR (sub-microscopic analysis).

RESULTS

Of the 773 participants enrolled in the study, 93.7% were from the rural area, of whom 97% were afebrile. The prevalence of microscopic and sub-microscopic Plasmodium spp. infection was 31.2% and 63.7%, respectively. Microscopic Plasmodium malariae infection was found in 1.3% of participants, while sub-microscopic studies detected a prevalence of 14.9% for P. malariae and 5.3% for Plasmodium ovale. The rate of co-infection of P. malariae or P. ovale with P. falciparum was 8.3% and 2.6%, respectively. Higher rates of sub-microscopic infection were reported for the urban area without seasonal fluctuation. In contrast, non-P. falciparum species infection was more pronounced in the rural area, with the associated risk of the prevalence of sub-microscopic P. malariae infection increasing during the dry season.

CONCLUSION

There is a need to include non-P. falciparum species in malaria control programs, surveillance measures and eradication strategies in the Republic of the Congo.

Plasmodium falciparum multiplicity of infection and pregnancy outcomes in Congolese women from southern Brazzaville, Republic of Congo

Background

Investigating whether the multiplicity of Plasmodium falciparum infection (MOI) is related to pregnancy outcomes, is of interest in sub-Saharan area where malaria is highly endemic. The present study aimed to characterize the genetic diversity of P. falciparum in women at delivery from Southern Brazzaville, and investigate whether the MOI is associated with maternal anaemia, preterm delivery, or low birth weight.

Methods

This was a cross sectional study carried out with samples collected between March 2014 and April 2015 from 371 women recruited at delivery at a Health Centre in southern Brazzaville, Republic of Congo. Matched peripheral, placental, and cord blood collected from each of the women at delivery were used for the detection of P. falciparum microscopic and submicroscopic parasitaemia, and parasite DNA genotyping by nested PCR.

Results

From 371 recruited women, 27 were positive to microscopic malaria parasitaemia while 223 women harboured submicroscopic parasitaemia. All msp-1 block 2 family allelic types (K1, MAD20 and RO33) were observed in all the three compartments of blood, with K1 being most abundant. K1 (with 12, 10, and 08 alleles in the peripheral, placental, and cord blood respectively) and MAD20 (with 10, 09, and 06 alleles in the respective blood compartments) were more diverse compared to RO33 (with 06, 06, and 05 alleles in the respective blood compartments). From the 250 women with microscopic and/or submicroscopic parasitaemia, 38.5%, 30.5%, and 18.4% of peripheral, placental and cord blood sample, respectively, harboured more than one parasite clone, and polyclonal infection was more prevalent in the peripheral blood of women with microscopic parasitaemia (54.5%) compared to those with submicroscopic parasitaemia (36.7%) (p = 0.02). The mean multiplicity of genotypes per microscopic and submicroscopic infection in peripheral blood was higher in anemic women (2.00 ± 0.23 and 1.66 ± 0.11, respectively) than in non-anaemic women (1.36 ± 0.15 and 1.45 ± 0.06, respectively) (p = 0.03 and 0.06). In logistic regression, women infected with four or more clones of the parasite were 9.4 times more likely to be anaemic than women harbouring one clone. This association, however, was only observed with the peripheral blood infection. No significant association was found between the MOI and low birth weight or preterm delivery.

Conclusions

These results indicate that the genetic diversity of P. falciparum is high in pregnant women from southern Brazzaville in the Republic of Congo, and the multiplicity of the infection might represent a risk for maternal anaemia.

Diagnosis of malaria in pregnancy: accuracy of CareStart™ malaria Pf/PAN against light microscopy among symptomatic pregnant women at the Central Hospital in Yaoundé, Cameroon

Background

The need to start treatment early for pregnant women who present with clinical features of malaria usually conflicts with the need to confirm diagnosis by microscopy (MP) before treatment, due to delays in obtaining results. Parasite sequestration in the placenta is also a problem. Rapid diagnostic tests (RDT), which detect soluble antigens, are a valuable alternative. The objective of this study was to evaluate pretreatment parasite prevalence by microscopy and by RDT and to assess the accuracy of RDT with MP as reference.

Methods

A prospective cross-sectional study was carried out at the obstetrical unit of the Central Hospital in Yaoundé, during the period January-August 2015. Consenting patients with symptoms of suspected malaria in pregnancy were recruited and a blood sample taken for MP and RDT before treatment was started. The estimates of diagnostic performance (with 95% confidence interval) were calculated in OpenEpi online software using the Wilson’s score. The agreement, as reflected by the Cohen’s kappa, was calculated and interpreted using known intervals.

Results

The results showed that, out of the 104 patients recruited, 69.2% (95%CI: 59.1–77.5) were MP positive while 77.94% (95%CI: 63.1–80.9) were RDT positive. The sensitivity of the malaria RDT was 91.67% (95%CI: 83.69–96.77) while the specificity was 53.13% (95%CI: 31.39–65.57). The diagnostic accuracy of the RDT with MP as reference was 79.81% (95%CI: 70.0–86.1). All cases were due to Plasmodium falciparum. A Cohen’s kappa of 0.45 (95%CI: 0.26–0.64) was obtained, consistent with a moderate agreement between the tests.

Conclusions

The diagnostic accuracy of the CareStart™ malaria Pf/PAN compared to microscopy was high, but not as desirable, with a false negative RDT at very high parasitaemia. In tertiary facilities, RDTs appear to provide a better diagnostic solution compared to microscopy. However, future studies with larger sample sizes should make this observation more generalizable; as missing a case could have serious consequences on pregnancy outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04109-6.