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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #382860

Research Project: Detection and Control of Foodborne Parasites for Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Unusual disseminated toxoplasmosis in an adult backyard chicken

item KULSHRESHTHA, VIKAS - Louisiana State University
item Dubey, Jitender
item VERMA, SHIV - Non ARS Employee
item RINALDI, MAX - Louisiana State University
item CORNAX, INGRID - Louisiana State University
item WAKAMATSU, NOBUK0 - Louisiana State University

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2021
Publication Date: 7/1/2021
Citation: Kulshreshtha, V., Dubey, J.P., Verma, S., Rinaldi, M., Cornax, I., Wakamatsu, N. 2021. Unusual disseminated toxoplasmosis in an adult backyard chicken. Veterinary Parasitology. 35(1):11-15.

Interpretive Summary: Food safety research is of paramount importance for agriculture and the public. Foodborne protozoon infections are a leading cause of death from foodborne illness in the United States, especially for individuals with weak immune systems such as children and HIV patients. USDA research in this area has borne undeniable results – including helping to cut the prevalence of Toxoplasma gondii by as much as 50 percent in the United States. The USDA provided the veterinary, clinical, and public health communities an indispensable resource by disseminating up to date scientific information on toxoplasmosis and its prevention. Humans become infected mostly by ingesting food and water contaminated with oocysts or by eating infected under cooked meat. Free range chickens (Gallus domesticus) are an important intermediate host for Toxoplasma gondii because they are preyed upon by cats that in turn excrete environmentally resistant oocysts. Although T. gondii is widely prevalent in free range/backyard chickens, clinical toxoplasmosis is rare. Here, the authors report a rare case of blindness and encephalitis because of toxoplasmosis in a chicken from Louisiana. This research was accomplished in 2017 before the redirection of Toxoplasma research by ARS in 2018

Technical Abstract: A female adult chicken was presented with one-week history of blindness and ataxia. Postmortem examination revealed that the right eye was covered with mucus and the cornea was cloudy. Upon microscopic examination, variable sized Toxoplasma gondii-like tissue cysts and tachyzoites were detected in various tissues including brain, spinal cord, right eye, optic nerve and heart, along with necrosis and mixed inflammatory infiltrates of lymphocytes, plasma cells and macrophages. The largest numbers of parasites were observed in the brain section. Immunohistochemistry with Toxoplasma-specific antibodies confirmed diagnosis. Limited genetic typing using the DNA extracted from the paraffin-embedded brain section of the chicken and 6 PCR-restriction fragment length polymorphism (RFLP) genetic markers revealed mixed type I and type III genotypes at SAG2, alt.SAG2, SAG3, GRA6, c22-8 and L358 loci. No apparent concurrent viral infection such as Marek’s disease or other bacterial and parasitic infectious diseases was seen, which is very unusual.