Prevalence and molecular identification of <i>Schistosoma haematobium</i> infection in two peri-urban areas of Lusaka, Zambia: a cross-sectional study

Abstract

ABSTRACT Background Schistosomiasis is one of the most prevalent neglected tropical diseases in Sub-Saharan Africa, causing substantial morbidity and millions of disability-adjusted life years (DALYs). Although the WHO aims to eliminate schistosomiasis as a public health problem in several countries by 2030, limited data on infection prevalence in Zambia has hindered effective Mass Drug Administration (MDA) coverage, contributing to the persistence and resurgence of the disease. Methods We assessed the prevalence of urogenital schistosomiasis in two peri-urban districts of Lusaka (Chongwe and Kafue). A total of 208 participants were enrolled, and infection status was determined using microscopy, serological assays, and molecular diagnostics. Results Prevalence was significantly higher in Chongwe than in Kafue, as detected by both microscopy and qPCR, demonstrating a strong association between infection and district location. No association was found between sex and infection in either district. However, a significant association between age and Schistosoma haematobium infection was observed across both sites. Molecular characterization of individual eggs revealed that S. haematobium × S. curassoni hybrids were the most prevalent species circulating in the study population. Conclusions Our findings reveal a high prevalence of urogenital schistosomiasis in at least two peri-urban areas of Lusaka, Zambia, indicating that transmission remains highly active and may be underestimated in national surveillance. Furthermore, the presence of hybrid species infecting humans highlights the need to consider livestock reservoirs when designing elimination strategies. These results provide updated information on the epidemiological situation of urogenital schistosomiasis in Zambia and will support planning and implementation within the WHO NTD agenda. AUTHOR SUMMARY Urogenital schistosomiasis remains a major public health concern in many parts of Sub-Saharan Africa, yet recent data from Zambia are limited, particularly in communities surrounding Lusaka. In this study, we assessed infection levels in two peri-urban districts, Chongwe and Kafue, using a combination of microscopy, serology, and molecular techniques to ensure accurate detection. We found substantial differences in prevalence between the two locations, with significantly higher infection rates in Chongwe, as well as a clear association between age and risk of infection. Molecular characterisation of parasite eggs revealed that hybrid Schistosoma haematobium × S. curassoni forms were the dominant circulating genotypes, indicating potential involvement of animal reservoirs in transmission. These findings demonstrate that transmission remains active and likely underestimated, and they highlight the importance of incorporating updated epidemiological data and potential zoonotic sources into future control and elimination strategies in Zambia.