Exposure to Toxoplasma gondii in captive zoo animals in Spain

Authors: CANO-TERRIZA, DAVID - University Of Cordoba; ALMERIA, SONIA - Food And Drug Administration(FDA); CABALLERO-GOMEZ, JAVIOUR - University Of Cordoba; JIMENEZ-MARTIN, DEBRA - University Of Cordoba; CASTRO-SCHOLTEN, SABRINA - University Of Cordoba; Dubey, Jitender; GARCIA-BOCANEGRA, IGNACIO - University Of Cordoba

Submitted to: Preventive Veterinary Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2020
Publication Date: 3/1/2020
Citation: Cano-Terriza, D., Almeria, S., Caballero-Gomez, J., Jimenez-Martin, D., Castro-Scholten, S., Dubey, J.P., Garcia-Bocanegra, I. 2020. Exposure to Toxoplasma gondii in captive zoo animals in Spain. Preventive Veterinary Medicine. 176:104930. https://doi.org/10.1016/j.prevetmed.2020.104930.
DOI: https://doi.org/10.1016/j.prevetmed.2020.104930

Interpretive Summary: Among these zoonotic pathogens, the protozoan parasite T. gondii is perhaps the most ubiquitous, having been identified in virtually all warm blooded animals and humans. 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. Infections in zoo animals, particularly cats, are of particular importance because children visiting zoos can become infected with T. gondii oocysts excreted by cats, including wild felids. This survey of zoos in Spain found evince a wide circulation of T. gondii in zoos, including wild felids. Captive zoo animals can be useful sentinel species to monitor T. gondii circulation in epidemiological scenarios with a close human-wildlife interface. Control measures should be implemented in zoo parks to minimize the risk of exposure of captive zoo species to T. gondii. The results will be of interest to zoo workers, veterinarians, parasitologists and public health workers.

Technical Abstract: A serosurvey was performed to assess exposure to Toxoplasma gondii in captive zoo animals in Spain and to determine the dynamics of seropositivity in some zoo species over time. Sera from 393 captive zoo animals belonging to 91 species were collected in eight zoos in Spain between 2007 and 2019. Additionally, 39 of the 393 animals from five of the analyzed zoos were longitudinally sampled. Anti-T. gondii antibodies were detected in 165 (42.0%; CI95%: 37.1-46.9) of 393 animals by the modified agglutination test (MAT, cut-off=1:25). Antibody titers of 1:25, 1:50, 1:100 and =1:500 were found in 25 (15.2%), 65 (39.4%), 26 (15.8%), and 49 (29.7%) of the seropositive animals, respectively. The feeding habit (carnivorous species) was a risk factor (OR= 5.6; P<0.001; CI95%: 3.8-9.0) potentially associated with T. gondii exposure. Eighteen (46.2%) of the 39 animals longitudinally sampled were always seropositive and five animals (12.8%) (two spotted hyaena [Crocuta crocuta], one blesbok [Damaliscus pygargus], one white rhinoceros [Ceratotherium simum] and one mouflon [Ovis aries musimon]) seroconverted during the study period. Our results evince a wide circulation of T. gondii in zoos, including wild felids in Spain. Captive zoo animals can be useful sentinel species to monitor T. gondii circulation in epidemiological scenarios with a close human-wildlife interface. Control measures should be implemented in zoo parks to minimize the risk of exposure of captive zoo species to T. gondii.