Supplemented nutrition decreases helminth burden and increases drug efficacy in a natural host-helminth system

Gastrointestinal helminths are common parasites of humans, wildlife, and
livestock, causing chronic infections. In humans and wildlife, poor
nutrition or limited resources can compromise individuals’ immune
response, predisposing them to higher helminth burdens. This relationship
has been tested in laboratory models by investigating infection outcomes
following reductions of specific nutrients. However, much less is known
about how diet supplementation can impact susceptibility to infection,
acquisition of immunity, and drug efficacy in natural host-helminth
systems. We experimentally supplemented the diet of wood mice (Apodemus
sylvaticus) with high quality nutrition and measured resistance to the
common gastrointestinal nematode Heligmosomoides polygyrus. To test
whether diet can enhance immunity to reinfection, we also administered
anthelmintic treatment at random in both natural and captive populations.
Supplemented wood mice were more resistant to H. polygyrus infection,
cleared worms more efficiently after treatment, avoided a post-treatment
infection rebound, produced stronger general and parasite-specific
antibody responses, and maintained better body condition. In addition,
when applied in conjunction with anthelmintic treatment, supplemented
nutrition significantly reduced H. polygyrus transmission potential. These
results show the rapid and extensive benefits of a well-balanced diet and
have important implications for both disease control and wildlife health
under changing environmental conditions.