Fleas, hosts and habitat: What can we predict about the spread of vector-borne zoonotic diseases

Vector-borne diseases of humans and wildlife are experiencing resurgence across the globe. I examine the dynamics of flea borne diseases through a comparative analysis of flea literature and analyses of field data collected from three sites in New Mexico: The Sevilleta National Wildlife Refuge, the Sandia Mountains and the Valles Caldera National Preserve (VCNP). My objectives were to use these analyses to better predict and manage for the spread of diseases such as plague (Yersinia pestis).;To assess the impact of anthropogenic disturbance on flea communities, I compiled and analyzed data from 63 published empirical studies. Anthropogenic disturbance is associated with conditions conducive to increased transmission of flea-borne diseases. Most measures of flea infestation increased with increasing disturbance or peaked at intermediate levels of disturbance. Future trends of habitat and climate change will probably favor the spread of flea-borne disease.;Rodents, including Gunnison's prairie dogs (Cynomys gunnisoni ), were trapped for three years (2004-2006). Blood and flea samples were tested for the presence of plague and another bacterial pathogen, Bartonella. I conduct two analyses with this data. The first examines prairie dogs and their flea communities in the VCNP. Prairie dogs experienced a plague epizootic in fall 2004, after which we found plague positive fleas and positive antibody titers in three prairie dogs. We noted an increased tendency for flea exchange opportunities in the spring before flea abundance peaked. Spring conditions, which favor presence and exchange of certain flea species, may be just as important for determining plague outbreaks as the summer conditions, which lead to build up in flea populations.;In the second analyses, I found 38% of the rodents of 30 species and 60% of fleas of 24 species positive for Bartonella. Bartonella infections typically lasted two months and the prevalence of Bartonella . Changes in prevalence related to host density and environmental gradients, point to the importance of both fleas and rodents in Bartonella transmission cycles.;This research shows environment influences the risk of flea-borne disease spread. It is likely that future trends of habitat and climate change will favor the spread of flea-borne diseases, including plague and Bartonella .