EFFECT OF NEEM EXTRACT AND IVERMECTIN ON MITE (SARCOPTES SCABIEI) IN EXPERIMENTALLY INFECTED RABBITS

Forty New Zealand male rabbits were used in this study and then classified into four equal groups (10 rabbits per each). The first group was designated as healthy control group (Non-infested and non-treated). The rabbits of second, third and fourth groups were experimentally infested with 50 mites (S. scabiei var. cuniculi) per each rabbit. The second group was not treated and served as positive control. The third group was subcutaneously injected with ivermectin 1 % (200 µg / kg bw) three times within a week interval. The fourth group was topically painted with a crude aqueous neem extract (20%) every three days for three consecutive weeks. Macro and microscopic lesions on the rabbits were scored weekly after last treatment. The number of live mites (larvae, nymphs and adults) on each rabbit was counted on the 14th , 28th and 42th day post treatment (PT). Blood samples were taken from ear veins of 5 rabbits from each group two times at 28th and 42th day PT for estimation of Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) enzymes activity, cholesterol and creatinine, total protein, albumin and globulins in serum. The averages of body weight and cumulative body weight gain were recoded. In vitro, the mortality % of S. scabiei var. cuniculi larvae was 100 % 48 h after exposure to crude aqueous neem extract (20 %) or ivermectin (1 %). The crude aqueous neem extract (20 %) was highly efficient against the mite's larvae resulted in 100 % mortality after 48 h. After exposure for 48 h, LC50 value was 11.680 % and the LT50 value was 33.307 h, after treatment with 10 %. In vivo, at 42th day PT, the index scores of rabbits infested with S. scabiei var. cuniculi and treated locally with crude aqueous neem extract (20 %) or ivermectin (1 %) were significantly decreased when compared with the infested and non-treated ones (positive control). Also, the efficacy of ivermectin (1 %) and crude aqueous extract of neem (20 %) was 100 % to control the infestation of S. scabiei on the rabbits. At 42th day PT, the levels of ALT, AST enzymes, creatinine and total cholesterol in rabbits treated with crude aqueous neem extract were decreased than those treated with ivermectin. However, the total protein, albumin and globulin in rabbits treated with crude aqueous neem extract (locally) were significantly increased when compared with those treated with ivermectin. Histopathologically, the liver of rabbits treated with ivermectin showed some degenerative changes, individual necrosis of hepatocytes and free RBCs in the sinusoids. The kidney of rabbits with ivermectin showed some degenerative changes and casts in renal tubules and glomeruli. However, the rabbits treated with neem extract showed normal histological architectures in both liver and kidney. The body weight and body weight gain in rabbits treated with crude aqueous neem extract (locally) were significantly increased when compared with those treated with ivermectin after 42 days PT. It could be concluded that the crude aqueous extract of neem (20 %) has acaricidal efficiency similar to ivermectin without side effect on liver and kidney. In addition, neem improves growth performance of rabbits infested with S. scabiei var. cuniculi.