Toxoplasmosis can be an acute or chronic disease that results from infection by the Toxoplasma gondii organism. T. gondii is transmitted by exposure to contaminated soil or water, infective cat feces, cysts in infected meat, or blood containing the proliferating form. It is estimated that 30 percent of cats and up to 50 percent of humans have been exposed to T. gondii; however, clinical illness is not common. Immunosuppressed cats and unborn kittens growing within a recently infected mother cat are at an increased risk of infection. The human fetus is at high risk if the mother is infected during pregnancy.
The manifestations and severity of the illness depend on the degree of tissue damage and the location of the T. gondii organisms. Sudden widespread infection usually is not fatal but may affect multiple organs such as the eye, central nervous system, and heart. Low grade, chronic tissue cysts usually cause no clinical signs unless the animal becomes immunosuppressed, allowing the organisms to proliferate and cause acute disease. Cats infected by feline leukemia virus (FeLV) or feline infectious peritonitis (FIP) are more likely to show clinical disease when infected with Toxoplasma organisms. The majority of cats that are infected with Toxoplasma have evidence of inflammation within the eye.
There are treatments available for toxoplasmosis but success will vary. Although residual effects of infection cannot be predicted prior to the course of treatment, eye problems generally respond better to treatment than advanced muscular or neurological disorders.
