Treatment for toxoplasmosis with a composition comprising a lincosamide and a spiropiperidyl derivative of rifamycik S

A method of reducing the severity of toxoplasmosis resulting from infection of a mammalian host with Toxoplasma gondii, which method comprises:

• administering to a host in need of said treatment, either after infection or before exposure to said infection, a therapeutically effective amount of a lincosamide in combination with a therapeutically effective amount of a compound that is a spiropiperidyl derivative of rifamycin S, wherein said derivative comprises an imidazole ring that includes carbons at positions 3 and 4 of the rifamycin ring, the carbon at position 2 of said imidazole ring also being a ring carbon at position 4 of a piperidine ring system, thereby forming a spiropiperidyl ring system, said spiropiperidyl ring system optionally comprising a lower hydrocarbon substituent on the nitrogen of said piperidine.