Dynamics of paediatric urogenital schistosome infection, morbidity and treatment:a longitudinal study among preschool children in Zimbabwe

Background Recent research has shown that in schistosome-endemic areas preschool-aged children (PSAC), that is, <=5 years, are at risk of infection. However, there exists a knowledge gap on the dynamics of infection and morbidity in this age group. In this study, we determined the incidence and dynamics of the first urogenital schistosome infections, morbidity and treatment in PSAC.Methods Children (6 months to 5 years) were recruited and followed up for 12 months. Baseline demographics, anthropometric and parasitology data were collected from 1502 children. Urinary morbidity was assessed by haematuria and growth-related morbidity was assessed using standard WHO anthropometric indices. Children negative for Schistosoma haematobium infection were followed up quarterly to determine infection and morbidity incidence.Results At baseline, the prevalence of S haematobium infection and microhaematuria was 8.5% and 8.6%, respectively. Based on different anthropometric indices, 2.2%–8.2% of children were malnourished, 10.1% underweight and 18.0% stunted. The fraction of morbidity attributable to schistosome infection was 92% for microhaematuria, 38% for stunting and malnutrition at 9%–34%, depending on indices used. S haematobium-positive children were at greater odds of presenting with microhaematuria (adjusted OR (AOR)=25.6; 95% CI 14.5 to 45.1) and stunting (AOR=1.7; 95% CI 1.1 to 2.7). Annual incidence of S haematobium infection and microhaematuria was 17.4% and 20.4%, respectively. Microhaematuria occurred within 3 months of first infection and resolved in a significant number of children, 12 weeks post-praziquantel treatment, from 42.3% to 10.3%; P<0.001.Conclusion We demonstrated for the first time the incidence of schistosome infection in PSAC, along with microhaematuria, which appears within 3 months of first infection and resolves after praziquantel treatment. A proportion of stunting and malnutrition is attributable to S haematobium infection. The study adds scientific evidence to the calls for inclusion of PSAC in schistosome control programmes

Distribution of schistosomiasis and soil transmitted Helminthiasis in Zimbabwe:Towards a national plan of action for control and elimination

Schistosomiasis and STH are among the list of neglected tropical diseases considered for control by the WHO. Although both diseases are endemic in Zimbabwe, no nationwide control interventions have been implemented. For this reason in 2009 the Zimbabwe Ministry of Health and Child Care included the two diseases in the 2009-2013 National Health Strategy highlighting the importance of understanding the distribution and burden of the diseases as a prerequisite for elimination interventions. It is against this background that a national survey was conducted.A countrywide cross-sectional survey was carried out in 280 primary schools in 68 districts between September 2010 and August 2011. Schistosoma haematobium was diagnosed using the urine filtration technique. Schistosoma mansoni and STH (hookworms, Trichuris trichiura, Ascaris lumbricoides) were diagnosed using both the Kato Katz and formol ether concentration techniques.Schistosomiasis was more prevalent country-wide (22.7%) than STH (5.5%). The prevalence of S. haematobium was 18.0% while that of S. mansoni was 7.2%. Hookworms were the most common STH with a prevalence of 3.2% followed by A. lumbricoides and T. trichiura with prevalence of 2.5% and 0.1%, respectively. The prevalence of heavy infection intensity as defined by WHO for any schistosome species was 5.8% (range 0%-18.3% in districts). Only light to moderate infection intensities were observed for STH species. The distribution of schistosomiasis and STH varied significantly between provinces, districts and schools (p<0.001). Overall, the prevalence of co-infection with schistosomiasis and STH was 1.5%. The actual co-endemicity of schistosomiasis and STH was observed in 43 (63.2%) of the 68 districts screened.This study provided comprehensive baseline data on the distribution of schistosomiasis and STH that formed the basis for initiating a national control and elimination programme for these two neglected tropical diseases in Zimbabwe

Prevalence of infection intensities of schistosome species and heavy infection with any schistosome species in Zimbabwe stratified by gender and province in 2011.

<p>*  =  Number examined</p><p><b>¤</b>  =  Chitungwiza is not a metropolitan province but a town</p

Prevalence distribution of schistosomiasis and STH among 13, 038 primary school children by settlement in Zimbabwe during 2011 school calendar.

<p>(HD  =  High density; LD  =  Low density)</p

Stratification of 68 districts in Zimbabwe according to prevalence of heavy infection with any schistosome species (morbidity) and the proposed intervention strategies in 2011.

<p><b>Key:</b></p><p>Complementary strategies  =  Health education, safe water and sanitation, environmental management and snail control.</p

(a) Point prevalence of <i>S. haematobium</i> in 280 primary schools in Zimbabwe during 2011 school calendar.

<p>(<b>b</b>) Point prevalence of <i>S. mansoni</i> in 256 primary schools in Zimbabwe during 2011 school calendar. (<b>c</b>) Point prevalence of hookworms in 256 primary schools in Zimbabwe during 2011 school calendar. (<b>d</b>) Point prevalence of <i>A. lumbricoides</i> in 256 primary schools in Zimbabwe during 2011 school calendar.</p

Prevalence of combined schistosomiasis and STH infection by province in Zimbabwe in 2011.

<p><b>*  = </b> Chitungwiza is not a metropolitan province but a town.</p

Prevalence of schistosomiasis and soil transmitted helminthiasis co-infection combinationsby province in Zimbabwe in 2011.

<p>Prevalence of schistosomiasis and soil transmitted helminthiasis co-infection combinationsby province in Zimbabwe in 2011.</p

Prevalence of schistosome and STH species by province in Zimbabwe in 2011.

<p><b>*  = </b> For each province, the number of participants screened for hookworms, <i>A. lumbricoides</i> and <i>T. trichiura</i> was the same.</p><p><b>**  = </b> The prevalence of parasite species was 0%, 95%CI could therefore not be calculated.</p

Classification of 68 districts in Zimbabwe according to prevalence and overlap of schistosomiasis and STH in 2011.

<p>Classification of 68 districts in Zimbabwe according to prevalence and overlap of schistosomiasis and STH in 2011.</p