Prophylactic efficacy of milbemycin D against multiple infection of Dirofilaria immitis in dogs

In order to examine the prophylactic effects of mylbemycin D (MD) against Dirofilaria immitis (D. immitis) infection, the experiment was carried out under the conditions mimicking natural infection of D. immitis. Fifteen filaria free beagles of age 3 to 9 months were inoculated with a total number of 110-250 larvae divided into 5-10 times over a period of 4- to 7-month, and doses of MD at 1.0mg/kg were given once every month for the same period. The infection rate of the medicated group was zero suggesting complete protection, while that of the non-medicated control groups ranged from 26.5 to 45.3% (mean, 32.7%).