Clinical toxoplasmosis in zoo animals and its management

Authors: Dubey, Jitender

Submitted to: Elsevier
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2022
Publication Date: 3/28/2022
Citation: Dubey, J.P. 2022. Clinical toxoplasmosis in zoo animals and its management. Elsevier. https://doi.org/10.1016/j.eas.2022.100002.
DOI: https://doi.org/10.1016/j.eas.2022.100002

Interpretive Summary: Among these zoonotic pathogens, the protozoan parasite Toxoplasma 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. Certain species of zoo animals, particularly the Australian marsupials (wallabies), New World Non-human primates (squirrel monkeys, lemurs), and some avian species are highly susceptible to clinical toxoplasmosis. In this invited review, Toxoplasma infections are reviewed. The results will be of interest to zoo workers, veterinarians, parasitologists and public health workers. No animals were experimentally infected and only published information in public domain was reviewed.

Technical Abstract: Infections by the protozoan parasite, Toxoplasma gondii, are widely prevalent in humans and animals worldwide. Toxoplasmosis in several animal species in zoos is of both clinical and public health importance. Among captive animals, T. gondii infections in Australasian marsupials (kangaroos, wallabies), New World non-human primates (squirrel monkeys, lemurs), certain wild felids (Pallas cats), and certain avian species (canaries and finches) can be devastating. Excretion of environmentally resistant oocysts by captive felids can contaminate the zoo environment and can be source of infections for visitors to zoo, zoo personnel, and animals in the zoo. Here, these aspects of T. gondii infections are reviewed, including prevention strategies.