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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 #322917

Title: Seroprevalence and isolation of viable Toxoplasma gondii from raptors in the southeastern USA

item LOVE, DAVID - The Wilds Conservation Center
item Kwok, Oliver
item VERMA, SHIV - Orise Fellow
item Dubey, Jitender
item BELLAH, JAMIE - Auburn University

Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2016
Publication Date: 5/31/2016
Citation: Love, D., Kwok, O.C., Verma, S.K., Dubey, J.P., Bellah, J. 2016. Seroprevalence and isolation of viable Toxoplasma gondii from raptors in the southeastern USA. Journal of Wildlife Diseases. 52:653-656. doi:10.7589/2015-10-269.

Interpretive Summary: Infection with the single celled parasite, Toxoplasma gondii is prevalent worldwide in humans and animals, and can cause serious disease in many species. Cats are the only definitive hosts for T. gondii, whereas all other hosts, including the raptors, are considered intermediate hosts. Ingestion of infected small mammals and birds is considered the most important source of T. gondii infection for cats, with epidemiologic data indicating that most cats become infected at the age after birth when they learn to hunt. A cat can excrete millions of environmentally resistant oocysts, and are the primary source of oocyst contamination in the environment. In humans, the ingestion of uncooked meat and food, as well as consumption of water contaminated with oocysts are the two major modes of transmission postnatally. Surveys for T. gondii infection in the main intermediate hosts, rodents and birds, are labor intensive, and often can be a human health risk due to the variety of zoonotic diseases where rodents act as the reservoir. Raptors, such as owls, may consume 100-300 small mammals and birds yearly depending on species, and are therefore considered a good indicator of the prevalence of T. gondii due to their consumption of other intermediate hosts of T. gondii. In the present study the authors found that several species of owls had antibodies to T. gondii. They genetically characterized a strain of T. gondii from a barred owl, for the first time, and found that it is of the genotype II, commonly found in humans and animals in the USA. These results will be of interest to biologists, parasitologists, and epidemiologists.

Technical Abstract: Raptors are good indicators of the prevalence of Toxoplasma gondii in the environment because they prey on small mammals and birds. These prey species are a major source of infection in felids, which shed the environmentally resistant oocysts. We assessed T. gondii infection in 281 opportunistically available raptors at a rehabilitation facility between 2012 and 2014. Antibodies to T. gondii were assayed by the modified agglutination test (MAT, cut-off 1:25) and found in serum of 22/71 red-tailed hawks (Buteo jamaicensis), 25/54 barred owls (Strix varia), 9/41 red-shouldered hawks (Buteo lineatus), 13/28 great horned owls, 6/20 broad-winged hawks (Buteo platypterus), 2/16 Eastern screech owl (Megascops asio), 12/13 bald eagles (Haliaeetus leucocephalus), 6/12 Cooper's hawks (Accipiter cooperii), 1/8 black vultures (Coragyps atratus), and 1/1 golden eagle (Aquila chrysaetos). Antibodies were not detected in 5 barn owls (Tyto alba), 3 American kestrels (Falco sparverius), 1 Mississippi kite (Ictinia mississippiensis), and 1 osprey (Pandion haliaetus). Viable T. gondii was isolated from the tissues of 1 seropositive barred owl and identified a strain having type II alleles at all 10 loci tested, except one (ToxoDB PCR-RFLP genotypes #3). Type II strain is the most common strain in the USA. Results of the present study indicate a high prevalence of T. gondii in some raptor species and the first reported genotyping from a barred owl. Key Words: genotype, isolation, raptor, serology, Toxoplasma gondii, type II