Public Health Significance of Human Toxoplasmosis

Abstract

Toxoplasmosis is a significant food-borne zoonotic disease that causes a wide range of clinical syndromes in humans, including pregnant women, immunosuppressed individuals, land and sea mammals, and various bird species. Felidae is the only definitive host that excretes a million oocysts of T. gondii in their feces, polluting the environment. T. gondii has a complex life cycle, with sexual reproduction occurring in cats, where oocysts are formed and excreted with feces. The meiosis of oocysts in the environment leads to the formation of sporozoites that are infectious to intermediate hosts, such as rodents and livestock animals. In these intermediate hosts, rapidly replicating tachyzoites are disseminated throughout the body, forming tissue cysts containing bradyzoites. Infected individuals become infected by ingesting oocysts from contaminated soil, water, or food. The transmission of toxoplasmosis is recognized as zoonotic transmission, with the primary route being through the ingestion of contaminated food or water, particularly undercooked or raw meat, and unwashed fruits and vegetables that have come into contact with the parasite’s oocysts. The signs and symptoms of toxoplasmosis can vary widely, with most healthy individuals having a normal immune system and mild symptoms resolving on their own.