Abstract
Prophylactic effect of levamisole hydrochloride to the developing stages of Dirofilaria immitis was studied in both the experimental and the field trials.
Experimental trials: Dogs were medicated orally with 2.5mg/kg/day of levamisole hydrochloride for 30days after experimental infection. They were sacrificed on the 143rd day of infection, but no worms were recovered from their right ventricles or pulmonary arteries. In non-medicated controls the mean recovery rate was 40.9%.
Field trials: Dogs were exposed to natural infection throughout the infectious season and additionally inoculated once with infective larvae to establish the infection steadily. They were divided into two groups. One group of nine dogs were orally given 2.5mg/kg/day of the drug every day for 6months, from June to November. The other group of three dogs were medicated in the same manner, except the drug was given every other day. Both groups were sacrificed at 151 or 152days after inoculation. Of them, 12 dogs had no worms. Three controls had 15 to 66worms, showing a mean recovery rate of 72.7%. No adverse reaction of this drug was recognized in any dogs.
