Toxoplasma gondii - The Facts

Authors: CASTRO, PABLO DAVID JIM - University Of Georgia; Dubey, Jitender

Submitted to: The Veterinary Nurse
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2019
Publication Date: 5/24/2019
Citation: Castro, P.E., Dubey, J.P. 2019. Toxoplasma gondii - The Facts. The Veterinary Nurse. 10(4). https://doi.org/10.12968/vetn.2019.10.4.182.
DOI: https://doi.org/10.12968/vetn.2019.10.4.182

Interpretive Summary: Among these zoonotic pathogens, the protozoan parasite T. gondii is perhaps the most ubiquitous, having been identified in the tissues of a variety of animal hosts, including both mammalian and avian species. 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. Veterinary staff that care for sick animals are concerned about the danger of getting toxoplasmosis from animals. This paper is specially written for humans who care for animals, especially cats.

Technical Abstract: The protozoan parasite, Toxoplasma gondii was initially isolated from the rodent, Ctenodactylus gundi, and it has been found worldwide from Alaska to Australia with nearly one third of the human population having been exposed to this parasite. All warm-blooded hosts, including humans, can be infected by any one of its three infective stages: tachyzoites, bradyzoites, and sporozoites. Felids are the definitive hosts of this intracellular pathogen. Although it usually causes mild disease or asymptomatic infection in immune competent adults, this parasite can cause devastating disease in congenitally infected children and those with depressed immunity. Because of its zoonotic potential, toxoplasmosis triggers the interest of the diverse medical and veterinary specialties. Consciousness needs to be increased that this disease can produce clinical cases not only in immunocompromised patients or through vertical transmission, but also in healthy patients. In this article, we will review the biology and the epidemiology of this parasite.