Ground-breaking vaccine may be key to controlling and eliminating bilharzia

orldwide, poverty and poor health are consistently linked. Diseases of poverty are not high on the global research agenda and tend to be neglected, but they are an enormous problem in the developing world.

One such disease is schistosomiasis, or bilharzia, caused by parasitic worms. Infestation happens when parasites released by certain types of freshwater snails come in contact with the skin or are swallowed. It’s second only to malaria in having the most devastating socioeconomic impact on communities.

The World Health Organisation estimates that at least 90% of people who need treatment for schistosomiasis live in Africa. Although it can be treated with cheap drugs, treatment does not prevent reinfection, and there is no vaccine available. Aside from having a severe impact on patients’ quality of life, this debilitating disease can lead to death when eggs remain lodged in the liver and other tissues such as the kidneys. A researcher who is committed to the challenge of finding ways to help patients overcome the disease is Dr Hlumani Ndlovu,

a lecturer in the Division of Chemical and Systems Biology at University of Cape Town. He and his team are working to develop a vaccine to eradicate bilharzia, investigating the immuno-biology of the disease using animal models to mimic infection in humans.

“There is an urgent need to understand the immuno-biology of schistosomiasis to facilitate the development of effective vaccines,” says Ndlovu. “The study was designed to contribute knowledge to address this important challenge. Our vision is to use the knowledge gained from the study to develop a solution that will boost the host’s B cell responses during chronic schistosomiasis to limit tissue pathology, particularly in the liver. This work will be undertaken using non-human primates that closely resemble humans. Efforts to secure funds to continue with our work are ongoing.”

This research could lead to the identification of candidate proteins or immune factors as targets for host-directed therapies to help combat liver fibrosis, which can lead to cirrhosis, liver failure, liver cancer and ultimately death.

Developing host-directed therapies would be game-changing for patients with chronic schistosomiasis, and can greatly improve their quality of life. Ndlovu’s studies have contributed immensely in the identification of immunological mechanisms and cellular subsets that can either be augmented or attenuated to control inflammatory tissue pathology, a response triggered by damage to living tissues.

Host-directed therapy acts via a hostmediated response to the pathogen rather than acting directly on it, like traditional antibiotics. It can change the local environment in which the pathogen exists to make it less favourable, stopping it from replicating. This would carry huge socioeconomic benefits and reduce the burden of disease in the developing world.

“Because schistosomiasis is a waterborne disease, developing a vaccine would have significant social and economic benefits,” he says. In addition to improving health, it would allow local communities to fish more freely, thereby contributing to the alleviation of poverty. It could also allow communities to offer water sports that could boost tourism in endemic countries.”