Parasites in the city: degree of urbanization predicts poxvirus and coccidian infections in House Finches (Haemorhous mexicanus)

Publication Type:

Journal Article

Authors:

Giraudeau, Mathieu; Mousel, Melanie; Earl, Stevan; McGraw, Kevin

Source:

PLoS ONE, PLoS ONE, Volume 9, Issue 2, p.e86747 (2014)

Call Number:

A14GIR01IDUS

URL:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0086747

Keywords:

Avipoxvirus, coccidians, Haemorhous mexicanus, House Finch, Isospora sp, poxvirus

Abstract:

Urbanization can strongly impact the physiology, behavior, and fitness of animals. Conditions in cities might also promote the transmission and success of animal parasites and pathogens. However, no studies have examined variation in the prevalence or severity of several distinct pathogens/parasites along a gradient of urbanization in animals or whether these infections increase physiological stress in urban populations. The authors measured the prevalence and severity of infection with intestinal coccidians (Isospora sp.) and the canarypox virus (Avipoxvirus) along an urban-to-rural gradient in wild male house finches (Haemorhous mexicanus). They also quantified an important stress indicator in animals (oxidative stress) and several parameters of urbanization, including human population density and land-use patterns within a 1-km radius of each trapping site. Prevalence of poxvirus infection and severity of coccidial infection were significantly associated with the degree of urbanization, with an increase of infection in more urban areas. The degrees of infection by the two parasites were not correlated along the urban–rural gradient. Levels of oxidative damage in plasma were not associated with infection or with urbanization metrics. These results indicate that the physical presence of humans in cities and the associated altered urban landscape characteristics are associated with increased infections with both a virus and a gastrointestinal parasite in this common songbird resident of North American cities. Though elevations in urban- or parasite/pathogen-mediated oxidative stress were not found, humans may facilitate infections in these birds via bird feeders (i.e., horizontal disease transmission due to unsanitary surfaces and/or elevations in host population densities) and/or via elevations in other forms of physiological stress (e.g., corticosterone, nutritional).