Research into the relative importance of Tabanidae (Diptera) in mechanical disease transmission. III. The epidemiology of anaplasmosis in a Dar-es-Salaam dairy farm.

Studies were made on a herd of 300 dairy cattle near Dar-es-Salaam, Tanzania from July 1967 to June 1970. Ticks were excluded by weekly spraying of insecticides. Berenil was injected every 4 weeks to prevent trypanosomiasis. During the first 1 1/2 years, 55 cases of infection with Anaplasma marginale occurred. Many of these were due to needle transmission during the Berenil injections but there was a seasonal increase during the 3 months when Tabanus taeniola became common, and 44% of the infections may have been transmitted by tabanids. When the needle transmission was stopped, some cases of infection by tabanids still continued but these were few because there was no longer any large reservoir of infection available for transmission.