Our recent HUGS publication in the Elsevier journal One Health is Malawi's first formal survey of caprine schistosomiasis. This report is a pivotal step towards broadening our understanding and deepening our appreciation of the transmission pathways of zoonotic schistosomes within southeastern Africa.
This investigation took place within three districts of southern Malawi - Mangochi, Chikwawa, and Nsanje - where we aimed to uncover Schistosoma mattheei's and Schistosoma haematobium's infection dynamics. We integrated molecular DNA diagnostic assays with a GPS animal tracking and praziquantel treatment sub-study.
The epidemiology of S. mattheei is very focal;in specific goat herds, only those with extensive daily water contact can be universally infected, whilst others living nearby remain completely free from infection. Of most significant concern, we documented a singular case of S. haematobium within a goat from Chikwawa that sheds first light on this unusual but highly important zoonotic transmission pathway.
Like our prior study on bovine schistosomiasis, our GPS tracking survey demonstrated that particular goats, together with cattle, likely spark infections in snails that then go on to infect people who share water contact sites with such animals. By combining GPS tracking with intermediate snail host surveillance, we have identified several spatial transmission hotspots between people, livestock and snails.
Like bovine schistosomiasis, the first praziquantel treatment in goats proved largely effective, achieving a 92.3% cure rate one week after administration. However, a significant proportion of these treated goats were reinfected at three-month examinations. This highlights that chemotherapy alone can only provide a short-term solution to curtail the emergence of hybrid schistosomes locally. Indeed, new One Health intervention strategies need to be developed.
In February 2025, the HUGS team's observations on zoonotic schistosomes will be discussed in a prestigious scientific meeting sponsored by the Royal Society, London titled Parasite evolution and impact in action: assessing the importance of hybrid schistosomes in Africa.
This Science+ meeting will bring together many international experts and complement several prior investigations on hybrid schistosomes elsewhere. We are particularly delighted that our collaborating colleague Professor Joanne Webster, Royal Veterinary College, London. will also present her ongoing work in West Africa for which she was recently awarded the Royal Society Leeuwenhoek Prize.