The Inside Scoop: Elucidating the Three-Way Relationship Between Schistosoma Mansoni, the Gut, and Vaccines

Schistosomiasis is a neglected tropical disease that affects over 250 million people worldwide. This blood fluke infection burdens communities and areas with limited to no access to clean fresh water. When a host is exposed to cercariae, the infectious agent, in a body of water, it matures in the host’s circulation into adult female and male worms. Copulated adult worms migrate to the mesentery, in the case of Schistosoma mansoni, and produce eggs that can cross the intestinal barrier and get excreted in the feces to continue the lifecycle. The effects of S. mansoni infection on the host are several. Schistosomiasis affects the host’s immune responses by causing a bias towards an anti-inflammatory response and a regulatory response chronically. The host’s fecal microbiome composition and diversity are also affected by schistosomiasis via the former’s dysbiosis towards an inflammatory composition. In addition, recent research has shown that helminths, including schistosomes, impair third-party vaccine responses in the infected hosts. Even though schistosomiasis can be treated chemotherapeutically, recurrent infections are a common problem in schistosome-endemic countries. In addition, the distribution of the medication can be limited in endemic areas where other infectious diseases are also prevalent such as HIV. The research presented here focuses on the longer term of enhancing vaccine responses in individuals immunocompromised because of helminth infections. To do so, this project has two main aims, one being to evaluate fecal microbiome and S. mansoni interactions to identify the presence or absence of global changes. The second aim confirms the effect of fecal microbiota transplants and antibiotics on mice infected with S. mansoni (2A). The second part of aim 2 records vaccine responses in infected mice subjected to fecal microbiota transplants to observe the role of microbiome on Schistosoma-caused vaccine failure.