[Current options for the diagnosis and therapy of toxoplasmosis in HIV-negative patients]

Infections caused by Toxoplasma gondii follow, in general, a mild or asymptomatic course. However, certain individuals, such as immunocompromised patients or those undergoing immunosuppressive therapy, pregnant women, newborns and patients with chorioretinitis, an ocular forms of toxoplasmosis, are at risk for more severe forms of toxoplasmosis. In these patients, rapid diagnosis and timely initiation of the appropriate treatment is of the utmost importance. The standard therapeutic regimen for the treatment of toxoplasmosis is represented by a combination of pyrimethamine and sulfadiazine. In European countries, this regimen is usually initiated during the 15th week of gestation. Until then, spiramycin is the treatment of choice. In newborns, congenital infection is usually treated with the standard therapeutic regimen which may be alternated with spiramycin. Severe ocular forms of toxoplasmosis are also usually treated with the standard regimen but sulfadiazine may be substituted by clindamycin. The preferred treatment in immunocompromised patients is, once again, the standard combination of pyrimethamine and sulfadiazine. However, due to frequent serious side effects, alternative treatments are possible. In some patients, especially those undergoing immunosuppression due to stem cell transplantation, primary prophylaxis of cerebral toxoplasmosis is achieved by co-trimoxazole. Reduced doses of the standard regimen may be used as secondary prophylaxis during severe immunosuppression in these patients. However, due to an increased risk of myelotoxicity, other therapeutic measures have to be used.