Toxoplasma gondii is a zoonotic protozoan parasite that can cause morbidity and mortality in humans, domestic animals, and terrestrial and aquatic wildlife. The environmentally robust oocyst stage of T. gondii is fundamentally critical to the parasite's success, both in terms of its worldwide distribution as well as the extensive range of infected intermediate hosts. Despite the limited definitive host species (domestic and wild felids), infections have been reported on every continent, and in terrestrial as well as aquatic environments. The remarkable resistance of the oocyst wall enables dissemination of T. gondii through watersheds and ecosystems, and long-term persistence in diverse foods such as shellfish and fresh produce. Here, we review the key attributes of oocyst biophysical properties that confer their ability to disseminate and survive in the environment, as well as the epidemiological dynamics of oocyst sources including domestic and wild felids. This manuscript further provides a comprehensive review of the pathways by which T. gondii oocysts can infect animals and people through the environment, including in contaminated foods, water or soil. We conclude by identifying critical control points for reducing risk of exposure to oocysts as well as opportunities for future synergies and new directions for research aimed at reducing the burden of oocyst-borne toxoplasmosis in humans, domestic animals, and wildlife.

Introduction: Toxoplasma gondii is an obligatory intracellular protozoan with a worldwide distribution. We reported here the cerebral toxoplasmosis in an Iranian HIV-positive patient. Case report: A 35-year-old woman that hospitalized at Golestan province, in summer 2016 because of dizziness, fever, and headache. After treatment, she showed severe pain and then paralysis symptoms. Magnetic resonance imaging revealed a small mass in the brain. In the previous analysis, she had shown the presence of HIV antigen using immunocytochemistry. The results of serological tests for toxoplasmosis showed toxoplasma IgG antibodies rate of 1785.6 mg/dl and toxoplasma IgM antibodies rate of 162.4 IU/ml. Conclusion: From public health importance viewpoint, it is a necessity to educate the people about possible transmission risk of T. gondii through contaminated food and drink sources. Unhygienic behaviors such as close contact with stray cats and also consumption of raw or semi-cooked meat must be avoided especially in case of immunosuppressed persons such as HIV-positive patients. On the other hand, detection of HIV/AIDS patients in a community is very important due to following them up with the diagnosis tests for all opportunistic infection especially toxoplasmosis.