Cultivation at 37°C of a Trypanosome (Trypanosoma theileri) from Cows with Depressed Milk Production.

SYNOPSIS. Cultures of Trypanosoma theileri were obtained at 36° and at 37.5°C. in a blood‐lysate medium inoculated with blood from three dairy cows showing subnormal milk production. The organisms were first seen after 4 days in the first subculture, reached a maximum number of about 500,000 per ml. on the 4th day of the second subculture, and attained about this same number on the 4th day of subsequent transfers. Crithidial forms predominated but trypanosomes of the blood‐stream type were also numerous. Cultures were not obtained from cows with normal milk production. The infected cows, although free from helminth parasites, showed a marked eosinophilia.