Intranasal Delivery of a S. mansoni Cathepsin B expressing Adenovirus Provides Sterilizing Immunity from Schistosomiasis

Schistosomiasis (schisto) is one of the most important helminthic parasitic diseases in the world. Over 700 million people are at risk of infection. Schisto is acquired by fresh-water parasites and causes debilitating illnesses that can last over 30 years leading to death. Praziquantel is an effective treatment, however drug resistance is emerging, and it does not protect from reinfection. To solve this problem, the formulation of an effective vaccine is pertinent. In recent clinical trials human adenovirus 5 (hAdV-5) has been used as an effective vector to deliver various vaccines for malaria and SARS-CoV-2. It is the hope of this project to develop a vaccine using the same hAdV-5 technology which has moved to clinical trials in previous years. When tested, this vaccine provided 90% protection from parasite infection. We plan to increase this protection by delivering our vaccine intranasally to stimulate immune responses in the lung where the parasite is most vulnerable and prevent infection 100%. The study will be run in both male and female animals to determine sex differences caused by our vaccine. It will also determine the vaccine's ability to harness the immune response by assessing antibody production, and response by immune cells in the blood and lungs. The reality of a schistosomiasis vaccine would not only prove useful to stop transmission of the parasite within tropical and sub-tropical regions (where it is commonly found), but also to travelling Canadians. Additionally, with increased immigration a vaccine which provides sterilizing immunity would reduce the burden of schistosomiasis on the Canadian public health system.