Host condition, seasonality and environmental factors explain parasite
community differences between urban and rural foxes
Abstract
Wildlife parasite communities are important for an OneHealth approach.
The external environment impacts host-associated communities directly
and via the hosts. Hosts in poor body condition are more susceptible to
infection and parasite mode of transmission will affect occurrence:
rural environments with better availability of intermediate hosts favour
trophic transmission, while urban environments, often with dense host
populations, favour direct transmission. We here study helminth
communities within their synanthropic red fox (Vulpes vulpes)
hosts (155 intestinal samples) using DNA metabarcoding of multiple
marker genes (18S rRNA, 28S rRNA, COI). Controlling for sampling bias by
incorporating DNA quantity and quality into models, we analysed the
effect of environmental (urbanisation, seasonality) and host-intrinsic
(weight, age, sex) variables on helminth communities. Helminth diversity
was increased in younger hosts, in foxes with lower body weight and in
those found in winter and spring. Host intrinsic drivers had smaller
effects on the composition of the community, which was impacted by
urbanisation, dependent on parasite transmission mode: surprisingly,
transmission in two-host lifecycles was more pronounced in urban Berlin
than in rural Brandenburg. Our results disagree with the prevailing
hypothesis that trophically transmitted helminths are less prevalent in
urban areas than in rural areas. Environmental drivers, i.e.
urbanisation, affected each helminth species in the community
differently, and we cannot generalise from helminth traits to their
occurrences in urbanised areas. Finding co-infestations with multiple
helminths and high infection intensity associated with poor body
condition, however, might be relevant for a OneHealth approach.