Ongoing research projects

WRC Project - Current status and future predicted distribution patterns of bilharzia transmitting snails and implications for vector-borne diseases in South Africa.

1 April 2020 –31 March 2023

Background 
Climate change is predicted to severely affect both aquatic ecosystems by changing rainfall patterns, air temperatures and the severity and frequency with which natural disasters such as floods and drought occur.This also poses a threat to human health as it may affect food security, air quality and the distribution and occurrence of infectious, food and vector-borne diseases. This is particularly true for regions such as sub-SaharanAfrica,that are already burdened by environmental disasters such as floods and drought and many tropical diseases. Schistosomiasis,commonly known as bilharzia, is an infection caused by the parasitic trematodes Schistosoma Spp.and infects both humans and animals.Schistosomiasis is considered a neglected tropical diseases by the WHO as treatment is available for humans and the negative effects are not considered severe, particularly in relation to other diseases such as malaria. However, continuous reinfection of schistosomiasis in both humans and animals poses serious health threats, and treatment resistant schistosomiasis has also started increasing in frequency. 

It is therefore imperative that this disease is continuously evaluated. The parasitic trematode is transmitted to humans through water bodies that are infested with the intermediate host snails(vectors). Evaluation of the intermediate host snails and prevalence of schistosomiasis took place in the 1950s to 1960s in South Africa. However, little research on the subject has taken place since, and it is unknown what the present status of the snails and the disease is in South Africa. In addition, with the threat of future predicted climate change it is unknown how environmental changes may affect the distribution of the snails and, consequently the disease. 

The present study proposes to address this lack in knowledge using a combined field and desktop based study approach.The study aims to model the distribution of Schistosoma Distributing snails in four endemic regions in South Africa by evaluating climatic changes from the 1960s to the present and to further model the potential predicted change in the snail distribution in relation to climate change. This will take place in conjunction with a field based assessment where snail sampling will occur and human interviews so as to assess the knowledge of people regarding schistosomiasis as well as the prevalence of the disease.