Abstract:

Background: Schistosomiasis is a water-borne parasitic disease with the highest socioeconomic impact after Malaria. Preventive chemotherapy using praziquantel has been used as the main intervention in endemic countries, including Tanzania. Recently, studies in West Africa reported that the occurrence of schistostosoma hybrid species among human of up to 36% is one of the factors suspected affected the efficacy of treatment. This study assessed the occurrence of Schistosoma haematobium x Schistosoma bovis hybrids and their effect on praziquantel treatment outcomes in Shinyanga and Misungwi districts, Northwestern Tanzania.

Methods: A population-based cross-sectional study was conducted. Urine samples were examined for S. haematobium using the urine filtration method. The occurrence of bovis x S. haematobium hybrids in the studied population was determined using Rapid Diagnostic Multiplex PCR.

Results: Out of 1.190 individuals examined, 123 (6.4%) were infected with schistosomma haematobium the prevalence decreased to 6 (0.3%) after the treatment. Males were significantly more infected with urogenital schistosomiasis than females (P <0.001). The prevalence of S. haematobium was significantly higher in school-aged children 7-14 years, however, the association was non-significant on multivariate logistic regression analysis (OR = 1.8, p = 0.218). 0f 115 successful amplified genes for cox 1 mitochondria DNA, the occurrence of Schistosoma haematobium x Schistosoma bovis hybrids infection was 4 (3.5%) varied significantly among villages (P=.035). Praziquantel yielded a satisfactory cure rate above 90% with no significantly differences among age groups, occupations and sexes (P>0.05).

Conclusion: Findings suggest that schistosomiasis is still a public health problem in the study area and S. haematobium x S. bovis hybrid exists. However, the occurrence of S. haematobium x S. bovis hybrid among infected individuals in this study is relatively small which hindered the accurate analysis of praziquantel efficacy against Schistosoma hybrid infection which needs further investigation. Another study with an extended period of assessment and with an increased sample size could improve the evaluation of the efficacy of PZQ on Schistosoma hybrids in the study.