Reservoir competence of wildlife host species for Babesia microti

Abstract

Human babesiosis is an increasing health concern in the northeastern United States, where the causal agent, Babesia microti, is spread through the bite of infected Ixodes scapularis ticks. We sampled 10 mammal and 4 bird species within a vertebrate host community in southeastern New York to quantify reservoir competence (mean percentage of ticks infected by an individual host) using real-time PCR. We found reservoir competence levels >17% in white-footed mice (Peromyscus leucopus), raccoons (Procyon lotor), short-tailed shrews (Blarina brevicauda), and eastern chipmunks (Tamias striatus), and <6% but >0% in all other species, including all 4 bird species. Data on the relative contributions of multiple host species to tick infection with B. microti and level of genetic differentiation between B. microti strains transmitted by different hosts will help advance understanding of the spread of human babesiosis.

Figure

Mean reservoir competence of 14 host species (10 mammals and 4 birds) for Babesia microti, southeastern New York, USA, 2008–2010. Error bars indicate SE. Reservoir competence is defined as the mean percentage of ticks infected by any individual host of a given species. Host species with <10 individual hosts sampled are indicated by an asterisk. See Table 1 for sample sizes. Single-letter abbreviations for genera along the left indicate Blarina, Didelphis, Glaucomys, Mephitis, Peromyscus, Procyon, Sciurus, Sorex, Tamias, Tamiasciurus, Catharus, Dumetella, Hylocichla, and Turdus, respectively.