Evaluation of leishmania major transmission by phlebotomus duboscqi in balb/c mice during sodium stibogluconate (pentostam) treatment.

Abstract

The mainstay treatment of leishmaniasis is pel tavalcnt antimony III the form of sodium stibogluconate (pentostarn'') and mcglumine antimoniate (glucatime"). The two drugs have been used with relative success for the last 40 years until recently when drug resistance was widely recorded. Other drugs used as a second line for the treatment of leishmaniasis include pentamidine, aminosidine and ampotecirin 13. Just like antimony, toxicity and drug resistance are the major constraints towards their use. In this study it was shown that pentostam when used at a high dosage of 200mg/kg bw/day and 400mg/ kg bw/day was able to reduce the infection rate ill Balb/c mice suffering from Leishmania major infection. The treatment led to a regression in the size of the lesion to O.12S±0.02mm (n=10) and 0.006±O.014mm (n=10) by the sixth week of treatment with 200mg/kg bw/dayand 400J11g/kg bw/duy respectively. Both dosages were able to eliminate most of the parasites from the liver, spleen and foot pad and a few parasites- that remained in these regions were usually disintegrated a sign that the drug had a lethal effect on them. Sand flies preferred feeding on mice that had not received antimony treatment or mice that had low antimony levels in blood. The sand flies preferred feeding far away from the site of antimony infection. feeding preference on the foot pad lesion was lower in those mice that had received treatment as compared to controls that had received 110 treatment (X2=p<O.OS). Transmission of Leishmania 1J1(~j(},. occurred during treatment. The rate of transmission was higher during treatment at a lower dosage of 200mg/kg bw/day as compared to a dosage of 400mg/kg bw/day. Transmission reduced drastically during treatment and there was minimal transmission rates hy the 30th day of treatment. The infectivity of the sand flies after feeding 011 the infected mice Oil treatment also reduced drastically with advanced treatment of the infected mice. The rate of reduction of infectivity was higher 011 sand flies that fed on infected mice at a higher dosage of 400mglkg bw/day as compared to those that fed 011 infected mice at a lower dosage of200mg/kg bw/day. This study shows that although Pentostarn" reduces the level of parasitaemia in Balb/c mice, transmission still occurs, however the level of transmission during treatment is dependent on the dosage of the drug and the time of treatment.