Community ecology and disease risk: lizards, squirrels, and the Lyme disease spirochete in California, USA

Vector-borne zoonotic diseases are often Maintained in complex transmission cycles involving multiple vertebrate hosts and their arthropod vectors. In the state of California, USA. the spirochete Borrelia burgdorferi, which causes Lyme disease, is transmitted between vertebrate hosts by the western black-legged tick, Ixodes pacificus. Several mammalian species serve as reservoir hosts of the spirochete, but levels of tick infestation, reservoir competence, and Borrelia-infection prevalence vary widely among Such hosts. Here, we model the host (lizards, Peromyscus mice, Californian meadow voles. dusky-footed wood rats. and western gray squirrels), vector, and pathogen community of oak woodlands in northwestern California to determine file relative importance of different tick hosts. Observed infection prevalence of B. burgdorferi in host-seeking I. pacificus nymhs was 1.8-5.3%, and our host-community model estimated an infection prevalence of 1.6-2.2%. The western gray squirrel (Sciurus griseus) was the only source of infected nymphs. Lizards, which are refractory to Borrelia infection, are important in feeding subadult ticks but reduce disease risk (nymphal infection prevalence). Species identify is therefore critical ill understanding and determining the local disease ecology.