Azadirachta indica (A. Juss.) reduces circulating Dirofilaria immitis microfilariae in vivo

The present study enumerates the effectiveness of ethanolic leaf extract of A. indica against circulating microfilariae (mf) of D. immitis in vivo of Canis familiaris. An ethanolic extract was prepared from the leaves of A. indica (EEA) and treated on dogs infected with the filarial nematode Dirofilaria immitis, the causative agent of canine cardiopulmonary dirofilariasis. Before treatment, all the infected dogs were vigilantly supervised for any natural fluctuation of mf count. Two doses; 25 and 50 mg/kg body weight/twice a day; both for 15 days were selected for in vivo tests along with a control group which received an empty capsule during the study period. The highest reduction of circulating mf was counted on day 60, showing mf reduction of 77.9% and 86.7% respectively for the two doses. Thereafter mf density increased with a minor change and maintained reduction of 49.5% and 64.1% on day 180 respectively. Additionally, no appreciable side effects in the treated dogs were recorded as evident from serum toxicity parameter analyses. In conclusion, the ethanolic formulation of A. indica leaves possesses considerable effectiveness against D. immitis in vivo with no toxic modification in the host after exposure. Thus, EEA appears to be a good alternative remedy against heartworm infection in infected dogs.