Suburban white-Tailed deer seropositive for Toxoplasma gondii from Chicago, Illinois

Authors: HOLLIS-ETTER, KARMEN - University Of Michigan; ANCHOR, CHRISTOPHER - Forest Preserve District Of Cook County; CHELSVIG, JAMES - Forest Preserve District Of Cook County; Dubey, Jitender; WARNER, RICHARD - University Of Illinois

Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2019
Publication Date: 5/17/2019
Publication URL: http://handle.nal.usda.gov/10113/6498326
Citation: Hollis-Etter, K.M., Anchor, C.L., Chelsvig, J.E., Dubey, J.P., Warner, R.E. 2019. Suburban white-Tailed deer seropositive for Toxoplasma gondii from Chicago, Illinois. Parasitology Research. 118:2271–2276. https://doi.org/10.1007/s00436-019-06347-1.
DOI: https://doi.org/10.1007/s00436-019-06347-1

Interpretive Summary: Toxoplasma gondii is estimated to chronically infect one third of the world’s human population, causing ocular toxoplasmosis in immunocompetent individuals and often-fatal encephalitis in the immunocompromised, as well as birth defects and mortality following vertical transmission to developing fetuses. Humans become infected postnatally by eating undercooked meat infected with T. gondii tissue cysts or by ingesting oocysts from the environment. Cats (domestic and wild) are the main reservoir of infection because they are the only hosts that can excrete the environmentally resistant stage, the oocyst. Oocysts are highly infectious for people and animals. White- tailed deer (WTD) are important in the epidemiology of toxoplasmosis for several reasons. They are a source of T. gondii infections for wild cats that can further spread infection. Humans can become infected by eating undercooked venison. Additionally, WTD are a sentinel for soil and herbage contamination by oocysts because they are herbivores and become infected only by ingesting Toxoplama oocysts. In the present study, T. gondii infection was found in 55.9% of 443 deer deer in the wild sampled in Illinois. The results will be of interest to biologists, parasitologists, public health workers, and hunters.

Technical Abstract: The presence and abundance of vertebrates influences the circulation of zoonotic diseases. White-tailed deer (Odocoileus virginianus) are widely distributed in North America and deer densities are frequently high in unhunted areas, including most major metropolitan regions. This study investigated the seroprevalence for Toxoplasma gondii from live-captured and culled deer sampled in two suburban forest preserves around Chicago, Illinois from 1995-99. Seroprevalence for T. gondii was 55.9% (n=443) and was significantly higher at the northern study site, Des Plaines (DP). Seroprevalence for T. gondii varied by year and month. Multivariate logistic regression (LR) screened main effects variables (age, sex, site, year, and month) by backward stepwise elimination. The final LR model for T. gondii contained all main effects variables. Deer served as effective wildlife sentinels for this serological investigation; deer inhabit the same environment as disease hosts and humans who recreate in suburban forest preserves. This study provides baseline data comparisons for future T. gondii suburban deer studies and information to public health and wildlife officials regarding the prevalence a parasitic pathogen present in two public forest preserves in Chicago, Illinois.