The effect of hookworm infection and urinary schistosomiasis on blood hemoglobin concentration of schoolchildren living in northern Mozambique

Schistosomiasis with a Focus on Africa

Schistosomiasis is a common neglected tropical disease of impoverished people and livestock in many developing countries in tropical Africa, the Middle East, Asia, and Latin America. Substantial progress has been made in controlling schistosomiasis in some African countries, but the disease still prevails in most parts of sub-Saharan Africa with an estimated 800 million people at risk of infection. Current control strategies rely primarily on treatment with praziquantel, as no vaccine is available; however, treatment alone does not prevent reinfection. There has been emphasis on the use of integrated approaches in the control and elimination of the disease in recent years with the development of health infrastructure and health education. However, there is a need to evaluate the present status of African schistosomiasis, primarily caused by Schistosoma mansoni and S. haematobium, and the factors affecting the disease as the basis for developing more effective control and elimination strategies in the future. This review provides an historical perspective of schistosomiasis in Africa and discusses the current status of control efforts in those countries where the disease is endemic.

Socioenvironmental Factors Influencing Distribution and Intensity of Soil-Transmitted Helminthiasis in the Brazilian Amazon: Challenges for the 2030 Agenda

Soil-transmitted helminthiasis (STHs) are poverty-related diseases with high prevalence rates in developing countries. The present study aims to describe the epidemiological scenario of STHs in an urban population in the Brazilian Amazon. A cross-sectional survey (n = 349 children aged 1–15 years) was carried out to obtain faecal samples and sociodemographic and sanitation data. Among the children, 143 (41%) were positive for at least one STH. Prevalence rates of infections by A. lumbricoides, T. trichiura, and hookworms were 24.4%, 42.6%, and 9%, respectively. A logistic regression multivariate model showed that infection with A. lumbricoides is significantly more frequent in children aged 11–15 years (odds ratio [OR] = 2.38; 95% confidence interval [CI] = 1.15–4.94; p=0.018) and the presence of latrines inside houses is a protection factor against ascariasis (OR = 0.38; 95% CI = 0.17–0.85; p=0.019). Positivity for T. trichiura is higher in the 5–10 (OR = 3.31; 95% IC = 1.85–5.89; p=0.001) and 11–15 age groups (OR = 3.16; 95% IC = 1.66–6.00; p=0.001), in children living in poor families (OR = 1.78; 95% IC = 1.01–3.14; p=0.045) and practicing open evacuation (OR = 2.07; 95% IC = 1.07–3.99; p=0.029). Hookworm infection is more frequent in children aged 11–15 years (OR = 6.70; 95% IC = 1.91–23.43; p=0.002), males (OR = 6.35; 95% IC = 2.00–20.14; p=0.002), and those living in stilt houses (OR = 3.52; 95% IC = 1.22–10.12; p=0.019). The use of albendazole in the last six months was a protection factor against hookworm infection (OR = 0.31; 95% IC = 0.10–0.96; p=0.042). The proportion of mild, moderate, and severe infections was 55.2%, 37.8%, and 7%, respectively, for A. lumbricoides, 72.4%, 24.3%, and 3.3% for T. trichiura, and 93.8%, 3.1%, and 3.1% for hookworms. Significantly higher worm burdens in T. trichiura and hookworm infections were associated with practicing open defecation and living in stilt houses. The data points to the need to improve sanitation infrastructure in Amazonian cities with similar sociodemographic and environmental characteristics.

Interactions between malnutrition, soil-transmitted helminthiasis and poverty among children living in periurban communities in Maranhao State, Northeastern Brazil

Poverty, malnutrition and neglected tropical diseases such as soil-transmitted helminthiases (STHs) interact in a multi-causal feedback network. This study aimed to assess the relationships between STHs, income and nutritional status of children in impoverished communities in the city of Caxias, Maranhao State, Northeastern Brazil. A cross-sectional survey (n=259 children) was carried out with the collection of fecal samples and assessment of sociodemographic, anthropometric, dietary and sanitation data. Hookworm infection and ascariasis presented prevalence rates of 14.3% and 9.3%, respectively. The logistic regression analysis showed that hookworm infection was more frequent in males (odds ratio [OR]=3.43; 95% confidence interval [CI]=1.45-8.08), children aged 11-15 years old (OR=3.72; 95% CI=1.19-11.62), children living in poor families (OR=2.44; 95% CI=1.04-5.68) and those living in rented houses (OR=5.74; 95%CI=1.91-17.25). Concerning ascariasis, living in the Caldeiroes community (OR=0.01; 95%CI=0-0.17) and belonging to the 11-15 years age group (OR=0.21; 95%CI=0.04-1.02) were protection factors. Poor children have a significantly lower frequency of consumption of meat, milk, vegetables, tubers and fruits than not poor children. The frequent consumption of meat, milk and tubers was associated with significant higher values in the parameter height-for-age, whereas the consumption of meat and milk positively influenced the weight-for-age. The frequencies of stunting, underweight and wasting were 8.1%, 4.9% and 2.9%, respectively. The multivariate model demonstrated that stunting was significantly associated with economic poverty (OR=2.82; 95%CI=1.03-7.70) and low weight was associated with male sex (OR=6.43; 95% CI=1.35-30.68). In conclusion, the study describes the interactions between the dimensions of development represented by income, STHs and nutritional status revealing the importance of raising income levels to improve the living conditions of families in impoverished communities in Northeastern Brazil.

Frequency and distribution of neglected tropical diseases in Mozambique: a systematic review

BACKGROUND

Neglected tropical diseases (NTDs) affect more than one billion people living in vulnerable conditions. In spite of initiatives recently contributing to fill NTDs gaps on national and local prevalence and distribution, more epidemiological data are still needed for effective control and elimination interventions.

MAIN TEXT

Mozambique is considered one of the countries with highest NTDs burden although available data is scarce. This study aims to conduct a systematic review on published available data about the burden and distribution of the different NTDs across Mozambique since January 1950 until December 2018. We identified manuscripts from electronic databases (Pubmed, EmBase and Global Health) and paper publications and grey literature from Mozambique Ministry of Health. Manuscripts fulfilling inclusion criteria were: cross-sectional studies, ecological studies, cohorts, reports, systematic reviews, and narrative reviews capturing epidemiological information of endemic NTDs in Mozambique. Case-control studies, letters to editor, case reports and case series of imported cases were excluded. A total of 466 manuscripts were initially identified and 98 were finally included after the revision following PRISMA guidelines. Eleven NTDs were reported in Mozambique during the study span. Northern provinces (Nampula, Cabo Delgado, Niassa, Tete and Zambezia) and Maputo province had the higher number of NTDs detected. Every disease had their own report profile: while schistosomiasis have been continuously reported since 1952 until nowadays, onchocerciasis and cysticercosis last available data is from 2007 and Echinococcosis have never been evaluated in the country. Thus, both space and time gaps on NTDs epidemiology have been identified.

CONCLUSIONS

This review assembles NTDs burden and distribution in Mozambique. Thus, contributes to the understanding of NTDs epidemiology in Mozambique and highlights knowledge gaps. Hence, the study provides key elements to progress towards the control and interruption of transmission of these diseases in the country.

Mitochondrial DNA reveals species composition and phylogenetic relationships of hookworms in northeastern Brazil

Hookworm infection persists focally in rural communities in Brazil. In this study, we analyze the mitochondrial nucleotide sequences obtained from hookworms infecting humans in order to characterize species composition and assess their genetic diversity and phylogenetic relationships. Field expeditions and cross-sectional surveys were carried out in three Brazilian municipalities from 2013 to 2017: Nossa Senhora de Nazaré (n = 605) and Teresina (n = 297), in the state of Piauí, and Russas (n = 213) in the State of Ceará. Parasitological methods were used to evaluate fecal samples. Hookworm-positive samples had a partial mtDNA cox1 amplified and sequenced. Maximum-likelihood and Bayesian analysis demonstrated two strongly-supported clades, including Group A, corresponding to Necator americanus, and Groups B and C, corresponding to Necator sp. Group A was divided into three main clusters: A1 grouped with Asian sequences, A2 grouped with African sequences, and A3 had only Asian sequences. Group B was closely related to Necator sp., showing a sequence similarity of 98%-99% with African samples circulating zoonotically among humans and non-human primates. Twenty three N. americanus haplotypes were identified. N. americanus Median-Joining network revealed three distinct groups, designated again as A1, A2, and A3. Group A1 presented a star-like shape, with one dominant haplotype. The molecular dating suggested that the two clades dividing N. americanus and Necator sp. began to diverge during the middle Pleistocene. The most recent common ancestor among N. americanus groups was dated to the late Pleistocene. Hookworms circulating in the studied communities are structured in well-defined subpopulations presenting both Asian and African genetic backgrounds. This reveals a double origin for hookworms in northeastern Brazil and opens up new possibilities in phylogeographic, evolutionary, and molecular epidemiological studies in regions where hookworms persists focally, despite control efforts. The presence of potentially zoonotic species and the specific identification of Necator sp. should be further investigated.

Intestinal parasitosis and anaemia among patients in a Health Center, North Ethiopia

Objective

The aim of this cross-sectional study was to determine the magnitude of intestinal parasitosis and anaemia in a Health Center, North Ethiopia.

Results

A total of 427 outpatients were enrolled and the median age of the participants was 22 years. The prevalence of intestinal parasitosis was 143 (33.5%). Age, place of residence and occupation were significantly associated with intestinal parasitosis. When we see parasite specific factors, significant associations were observed for source of drinking water (P = 0.02), age (P < 0.001) and family size (P = 0.003), respectively with Entameba histolytica, Hookworm and Giardia lamblia infections. The overall prevalence of anaemia was 35 (8.2%). The mean haemoglobin concentration among the study participants was 12.8 mg/dl. The highest prevalence of anemia was recorded for the age group of 15–19 years (29.6%). The proportion of anemia among intestinal parasite -infected and non-infected participants was 10.7 and 7.0%, respectively. Study participants infected with S. stercoralis and hookworm were more likely to develop anaemia than the non- infected ones; AOR (adjusted odds ratio) = 5.3, 95% CI (1.01–27.4); P = 0.028 and AOR = 11.1, 95% CI (3.36–36.9); P = 0.000, respectively.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-2957-2) contains supplementary material, which is available to authorized users.

Anaemia in school-aged children in an Australian Indigenous community

OBJECTIVE

Indigenous Australians have poorer health outcomes compared to the non-Indigenous population. Malnutrition, and subsequently iron-deficiency anaemia, impairs childhood development. The aim of this study was to identify the prevalence of anaemia in school-aged children of an Australian Indigenous community and evaluate the effectiveness of treatment.

DESIGN

A retrospective cohort study.

SETTING

A Northern Territory Indigenous community.

PARTICIPANTS

Two hundred and one school-age students (5-15 years old) undergoing annual school screening.

MAIN OUTCOME MEASURES

Presence of anaemia. Anaemic and non-anaemic students were compared to determine any differences in age, gender, BMI and past history of anaemia. The response to treatment was analysed using initial and repeat haemoglobin results.

RESULTS

Altogether, 201 students were screened with 105 (52%) classified as anaemic. No significant association was found between anaemic students and age, gender, BMI or prior history of anaemia. After treatment, the mean rise in haemoglobin was 13% (95% CI 11-15) at the 4-week interval. Age (P = 0.17), gender (P = 0.53) and weight (P = 0.14) were not significantly associated with treatment efficacy. Only 11 students (17%) were still anaemic after treatment.

DISCUSSION

Anaemia in Indigenous Australian school-aged children is a major public health issue. The prevalence of anaemia in this population is 52% and many times higher than that of the general Australian population. As per current guidelines, the recommended treatment is effective in over 80% at the 4-week interval. Community wide interventions are required to combat this alarming issue.

Prevalence of Schistosoma haematobium Infection among School-Age Children in Afar Area, Northeastern Ethiopia

In this study, the prevalence and intensity of Schistosoma haematobium infection was determined among school-age children living in the Middle and Lower Awash Valley, Afar Regional State of Ethiopia. Between February and May 2014, urine samples were collected from 885 school-age children (5–16 years of age) from the Middle (n = 632; 4 villages) and Lower (n = 253; 3 villages) Awash Valley. All samples were processed using urine filtration to detect and quantify S. haematobium eggs. In addition, a subset of the urine samples was tested for hematuria using a urine dipstick (n = 556). The overall prevalence was 20.8% (95% Confidence Interval (CI) = 18.1%, 23.5%), based on urine filtration but the prevalence considerably varied across villages both in the Middle (from 12.5% to 37.0%) and Lower Awash Valley (from 0 to 5.3%). The overall mean urine egg count (UEC) among the infected children was 4.0 eggs/10 ml of urine (95% CI = 2.43, 5.52). The infection intensity varied from 0.4 eggs/10 ml of urine to 7.7 eggs/10 ml of urine in the Middle Awash Valley, and from 0 to 1.1 eggs/10 ml of urine in Lower Awash Valley. Age and sex were not associated with S. haematobium infection based on the multivariable logistic regression model. The prevalence of hematuria was 56.3% (95% CI = 52.2%, 60.4%) among a subset of the study participants (556) examined using the urine dipstick. The prevalence of hematuria also varies with villages from 8.3% to 93.2%. In conclusion, the prevalence of S. haematobium infection in the Middle Awash Valley was high and it varies across villages. Hence, children living in the present study villages of the Middle Awash Valley need to be treated with praziquantel to reduce morbidity and disrupt transmission.

Hematological and hepatic alterations in Brazilian population heavily exposed to organochlorine pesticides

The aim of this study was to investigate the frequency of hematological and hepatic alterations and possible association with serum levels of beta-hexachlorocyclohexane (beta-HCH), p,p'-DDE, and hexachlorobenzene (HCB) among residents in an area heavily contaminated with organochlorine (OC) pesticides. A cross-sectional study was conducted in 415 male and 432 female residents aged >14 years. Serum samples were collected and analyzed for OC pesticides concentrations and biochemical parameters. Frequencies of hematological and hepatic alterations were calculated for each gender. Association between beta-HCH, p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene), and HCB levels and presence of alterations was determined by logistic regression stratified by gender and controlling for confounders. Highest frequencies were observed for eosinophilia (23% men and 18% women), low hemoglobin (12% men and 15% women), and low erythrocyte count (12% men). High levels of bilirubin, glutamic-oxaloacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) were observed, respectively, in 10, 11, and 12% of men and <10% of women. Gamma-glutamyl transferase (GGT) was elevated in 26 and 25% of males and females, respectively. Multivariate analysis revealed associations between eosinophilia and beta-HCH in men (OR = 1.06, 95%CI = 1.01-1.12) and women (OR = 1.05, 96%CI = 0.99-1.11), p,p'-DDE in men (OR = 1.03, 95%CI = 0.99-1.06) and women (OR = 1.02, 95%CI = 0.99-1.06), and HCB in women (OR = 1.54, 95%IC = 0.85-4.45). Beta-HCH was found to be associated with increased risk of elevated bilirubin in females (OR = 1.18, 95%CI = 1.07-1.29) and males (OR = 4.21, 95%CI = 1.87-9.47 for fourth vs. first quintile). Thus, OC pesticides may exert adverse effects on hematopoietic tissue and liver in populations chronically exposed to high levels of these compounds.