What is the causative agent of toxoplasmosis?

The causative agent of toxoplasmosis is a protozoan called Toxoplasma gondii. This single-celled organism can infect various hosts, including humans and animals, particularly cats, which are the definitive hosts. Infection occurs through several routes, such as ingestion of oocysts from contaminated food or water, transplacental transmission from mother to fetus, or consumption of undercooked meat containing tissue cysts.

Understanding that toxoplasmosis is caused by a protozoan is crucial for appropriate diagnosis and treatment, as well as for implementing preventive measures, especially in vulnerable populations such as pregnant women and immunocompromised individuals. The other choices—hookworms, bacteria, and viruses—represent different groups of pathogens that cause various diseases but are not responsible for toxoplasmosis. Each group has distinct characteristics and modes of transmission, underscoring the importance of identifying the correct pathogen in clinical veterinary and human medicine.