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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #383763

Research Project: Detection and Control of Foodborne Parasites for Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Toxoplasmosis

item LAPPIN, M - Colorado State University
item Dubey, Jitender

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/30/2021
Publication Date: 3/15/2022
Citation: Lappin, M.R., Dubey, J.P. 2022. Toxoplasmosis. In: Sykes, J.E., editor. Greene's Infectious Diseases of the Dog and Cat. 5th Edition. St. Louis, MO: Elsevier. p.1151-1162.

Interpretive Summary: Toxoplasmosis is a worldwide zoonosis. The USDA provided the veterinary, clinical, and public health communities an indispensable resource by disseminating up to date scientific information on toxoplasmosis and its prevention. Humans become infected mostly by ingesting food and water contaminated with oocysts or by eating infected under cooked meat. Toxoplasmosis can cause serious illness in humans and animals. Here, the authors provide information on toxoplasmosis in companion animals, written for small animal practioners.This information will be useful to parasitologists, biologists and public health workers. No experiments or surveys were performed since the redirection of USDA’s program on toxoplasmosis.

Technical Abstract: Overview of Toxoplasmosis First Described: The organism that was ultimately named Toxoplasma gondii was first described in France in 1908 (Nicolle and Manceaux).1 Cause: Toxoplasma gondii, a coccidian protozoan parasite (phylum Apicomplexa). Affected Host Species: Cats are the definitive host and are the only species known to complete the sexual phase of T. gondii culminating in the passage of oocysts in feces. Cats and most other vertebrates can serve as intermediate hosts; invertebrates can serve as transport hosts by mechanical carriage of T. gondii oocysts. Geographic Distribution: T. gondii has a worldwide distribution except in the absence of cats Major Clinical Signs: Fever, ocular inflammation, ataxia, seizures, muscle pain, and respiratory distress are the most common clinical signs in cats; dogs have similar signs but develop illness less frequently than cats. Differential Diagnoses: In the dog, Neospora caninum induces the most similar clinical signs; many other chronic intracellular bacterial infections and fungal infections in dogs and cats need to be considered as differential diagnoses for many of the clinical and laboratory abnormities induced by T. gondii. Human Health Significance: There is significant risk to the fetus after transplacental infection and to any immunocompromised person; whether significant effects on human behavioral abnormalities are induced by infection is still debated.