The Relation between Host and Parasite Abundance Along an Urban-Rural Gradient

Among the many zoonotic diseases, cryptosporidiosis is often of high importance because of its prevalence in industrialized countries. This disease is a result of a gastro-intestinal parasite, Cryptosporidium. Traditionally, aquatic mammalian hosts, such as beaver, were recognized as the primary vectors for Cryptosporidium; however, recent studies have suggested that terrestrial small mammals may also be important hosts. Environmental changes, natural or through human intervention, alter ecological interactions and host-parasite relations tending towards higher infestation rates in fragmented areas. We predict that host-parasite abundance will fit a density-dependent model. Four different landscape types were identified from the Greater Chicago region: urban, suburban, agricultural, and rural. Within each of these four regions the abundance of Peromyscus leucopus (white-footed mouse), the main terrestrial competent host, was estimated using mark-and-recapture. DNA from fecal material collected from Peromyscus is purified and isolated then subjected to Quantitative PCR. A total of 429 individuals were captured during the fall of 2014 and 2015. The rural region clearly had the greatest host abundance, with suburban and agricultural being low, and urban areas having intermediate host abundance. A large group of interconnected preserves in the rural region has sufficient open green land to support high densities of hosts. The intermediate host numbers in urban areas could be attributed to habitat fragmentation, reduction in predation, and food-provisioning by humans. Positive samples from qPCR will be sent to the CDC for genomic analysis of the parasite to determine the prevalent strains among regions