Vanessa Ezenwa, Assoc Prof, Odum School of Ecology & Dept of Infectious Diseases at the University of Georgia presents:

Helminth-microbe co-infection: insights from a natural system
Co-infection with worms can have profound effects on a host’s response to microbes, and an increasing number of studies are investigating the consequences of worm-microbe co-infection in laboratory settings. To better understand the dynamics of co-infection in natural systems, we used a free-ranging population of African buffalo to explore the consequences of worm infection for bovine tuberculosis (BTB). We followed 200 animals for four years to test the effects of anthelmintic treatment and host resistance on individual and population-level outcomes of BTB infection. We found that de-worming had no effect on individual risk of infection, but enhanced survival of BTB-infected individuals, translating into a higher basic reproductive number for BTB with treatment. Host resistance to worm infection also had no effect on individual risk, but buffalo that were naturally worm-free were more likely to die of BTB infection. The distinct effects of de-worming versus natural resistance on BTB severity arise from differences in BTB dissemination in the body. Our work shows that different ways of being worm-free (i.e. artificial treatment vs. natural resistance) have distinct outcomes for microbial co-infection.