Summaryobjective To predict the spatial distributions of Schistosoma haematobium and S. mansoni infections to assist planning the implementation of mass distribution of praziquantel as part of an on-going national control programme in Tanzania.methods Bayesian geostatistical models were developed using parasitological data from 143 schools. results In the S. haematobium models, although land surface temperature and rainfall were significant predictors of prevalence, they became non-significant when spatial correlation was taken into account. In the S. mansoni models, distance to water bodies and annual minimum temperature were significant predictors, even when adjusting for spatial correlation. Spatial correlation occurred over greater distances for S. haematobium than for S. mansoni. Uncertainties in predictions were examined to identify areas requiring further data collection before programme implementation.conclusion Bayesian geostatistical analysis is a powerful and statistically robust tool for identifying high prevalence areas in a heterogeneous and imperfectly known environment.

Abstract. We conducted a community-based study of 457 women aged 18-50 years living in eight rural villages in northwest Tanzania. The prevalence of female urogenital schistosomiasis (FUS) was 5% overall but ranged from 0% to 11%. FUS was associated with human immunodeficiency virus (HIV) infection (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.2-13.5) and younger age (OR = 5.5 and 95% CI = 1.2-26.3 for ages < 25 years and OR = 8.2 and 95% CI = 1.7-38.4 for ages 25-29 years compared with age > 35 years). Overall HIV prevalence was 5.9% but was 17% among women with FUS. We observed significant geographical clustering of schistosomiasis: northern villages near Lake Victoria had more Schistosoma mansoni infections ( P < 0.0001), and southern villages farther from the lake had more S. haematobium ( P = 0.002). Our data support the postulate that FUS may be a risk factor for HIV infection and may contribute to the extremely high rates of HIV among young women in sub-Saharan Africa.

BackgroundMalaria, schistosomiasis and soil transmitted helminth infections (STH) are important parasitic infections in Sub-Saharan Africa where a significant proportion of people are exposed to co-infections of more than one parasite. In Tanzania, these infections are a major public health problem particularly in school and pre-school children. The current study investigated malaria and helminth co-infections and anaemia in school and pre-school children in Magu district, Tanzania.MethodologySchool and pre-school children were enrolled in a cross-sectional study. Stool samples were examined for Schistosoma mansoni and STH infections using Kato Katz technique. Urine samples were examined for Schistosoma haematobium using the urine filtration method. Blood samples were examined for malaria parasites and haemoglobin concentrations using the Giemsa stain and Haemoque methods, respectively.Principal FindingsOut of 1,546 children examined, 1,079 (69.8%) were infected with one or more parasites. Malaria-helminth co-infections were observed in 276 children (60% of all children with P. falciparum infection). Malaria parasites were significantly more prevalent in hookworm infected children than in hookworm free children (p = 0.046). However, this association was non-significant on multivariate logistic regression analysis (OR = 1.320, p = 0.064). Malaria parasite density decreased with increasing infection intensity of S. mansoni and with increasing number of co-infecting helminth species. Anaemia prevalence was 34.4% and was significantly associated with malaria infection, S. haematobium infection and with multiple parasite infections. Whereas S. mansoni infection was a significant predictor of malaria parasite density, P. falciparum and S. haematobium infections were significant predictors of anaemia.Conclusions/SignificanceThese findings suggest that multiple parasite infections are common in school and pre-school children in Magu district. Concurrent P. falciparum, S. mansoni and S. haematobium infections increase the risk of lower Hb levels and anaemia, which in turn calls for integrated disease control interventions. The associations between malaria and helminth infections detected in this study need further investigation.

The study aimed to describe morbidity patterns due to intestinal schistosomiasis in adults living in two villages along the southern shores of Lake Victoria, Mwanza District, Tanzania. Nine hundred and fifty persons from Msozi and 497 from Sangabuye, aged between 14 and 87 years, were examined by abdominal ultrasound according to the Niamey protocol. Liver image patterns (LIP) A and B were considered normal and C-F as distinct periportal fibrosis (PPF). The frequency of PPF was higher in Msozi (41.5%) than in Sangabuye (16.7%) (P<0.001) and was associated with high prevalence and intensity of Schistosoma mansoni infection. PPF was shown to be more common in males than females. Abnormal increase of segmental branch wall thickness (SBWT) and dilated portal vein diameter (PVD) were also more common among males than females. Hepatomegaly and splenomegaly were frequently encountered in both villages. The LIPs were positively correlated to size of SBWT and PVD but not to size of left liver lobe or spleen. In the study communities the risk of developing PPF differed greatly among individuals depending on various risk factors especially alcohol consumption.

BackgroundPraziquantel at 40 mg/kg in a single dose is the WHO recommended treatment for all forms of schistosomiasis, but 60 mg/kg is also deployed nationally.Methodology/Principal FindingsFour trial sites in the Philippines, Mauritania, Tanzania and Brazil enrolled 856 patients using a common protocol, who were randomised to receive praziquantel 40 mg/kg (n = 428) or 60 mg/kg (n = 428). While the sites differed for transmission and infection intensities (highest in Tanzania and lowest in Mauritania), no bias or heterogeneity across sites was detected for the main efficacy outcomes. The primary efficacy analysis was the comparison of cure rates on Day 21 in the intent-to-treat population for the pooled data using a logistic model to calculate Odd Ratios allowing for baseline characteristics and study site. Both doses were highly effective: the Day 21 cure rates were 91.7% (86.6%–98% at individual sites) with 40 mg/kg and 92.8% (88%–97%) with 60 mg/kg. Secondary parameters were eggs reduction rates (ERR), change in intensity of infection and reinfection rates at 6 and 12 months. On Day 21 the pooled estimate of the ERR was 91% in both arms. The Hazard Ratio for reinfections was only significant in Brazil, and in favour of 60 mg/kg on the pooled estimate (40 mg/kg: 34.3%, 60 mg/kg: 23.9%, HR = 0.78, 95%CI = [0.63;0.96]). Analysis of safety could not distinguish between disease- and drug-related events. 666 patients (78%) reported 1327 adverse events (AE) 4 h post-dosing. The risk of having at least one AE was higher in the 60 than in the 40 mg/kg group (83% vs. 73%, p<0.001). At 24 h post-dosing, 456 patients (54%) had 918 AEs with no difference between arms. The most frequent AE was abdominal pain at both 4 h and 24 h (40% and 24%).ConclusionA higher dose of 60 mg/kg of praziquantel offers no significant efficacy advantage over standard 40 mg/kg for treating intestinal schistosomiasis caused by either S. mansoni or S. japonicum. The results of this study support WHO recommendation and should be used to inform policy decisions in the countries.Trial Registration Controlled-Trials.com ISRCTN29273316 ClinicalTrials.gov NCT00403611