The effect of eustigmaeus johnstoni trombid mite on the transmission and development of leishmania major parasite by philebotomous duboscqi
Inanga, Josphat Kaunga
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The development of Phlebotomus duboscqi (Diptera Psychodidae) has not been observed in its natural habitats, Therefore most information on Phlebotomus duboscqi has been derived from studies carried out under laboratory conditions. Laboratory rearing of Phlebotomus duboscqi (sand fly) vectors is a pre-requisite to understanding their life cycles, mechanisms of disease acquisition, parasite development, transmission dynamics, and the effects of parasites on the life cycle of the sand fly. In their natural habitats, sand flies are usually infested by ectoparasite articularly Eustigmaeus johnstoni,a trombid mite of the order Prostigrnata. It has been observed that mite infestation affects the established sand fly colonies in captivity. Controlling these mites has proved to be difficult because of their free-living and parasitic life cycles. They have been observed clinging on adults sand flies and feeding on their eggs and larvae. This is thought to adversely affect the development of sand fly and hence Leishmania major parasite acquisition and transmission. This study was carried out in the Leishmania laboratory at the Centre for Biotechnology Research and Development (CBRD) in Kenya Medical Research Institute (KEMRI). The study aimed at determining the developmental stages of E. johnstoni trombid mites and investigated the effects of its feeding, fecundity, longevity, mortality and transmission of Leishmania major by Phlebotomus.duboscqi. The longevity of mites fed on different diets was investigated. A group of sand flies was infested with mites and the fecundity, longevity and mortality were compared with that of the control un infested group. The results obtained from this study showed that the number of exposed female sand flies laid a mean number of 28 .19 eggs which was significantly higher than the mean number of 10.35 eggs which were laid by sandflies which were not exposed to Ejohnsoni. Chi -square analysis of the number of sandflies that laid eggs and those which did not lay eggs in the two groups was (x2=10.53, df=1) <0.05.Analysis of the difference of mean number of eggs laid by the two groups was(x2=24.44, df=l) P<0.05 which showed a significant difference. The life cycle of Ejohnstoni (Egg, larva, nymph and adult).In another experiment, the mites infested sand flies and the control group was fed on mice infected with L. major and the development of the L. major was studied in the sand fly. The developmental pattern was compared I' with that of the controls. It was observed that in both groups the bites caused lesions on he hind footpads of the clean BALB/c mice.Understanding the life cycle of these mites will help in controlling them.
- MST-Zoological Sciences