Browsing by Author "Jayanetti, S.R."

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    Effect of The Domestic Characteristic on Colonization of Phlebotomine Sand Flies: A Case Study in Anuradhapura District, Sri Lanka
    (Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Nayakarathna, N.M.N.G.; Ganehiarachchi, G.A.S.M.; Rajapakse, R.P.V.J.; Jayanetti, S.R.
    Cutaneous Leishmaniasis (CL)is an endemic vector-borne disease in Sri Lanka.It is caused by protozoan parasite Leishmania species and transmitted via infective bite of female Phlebotomine sand flies (Diptera: Psychodidae). The public health importance of this disease is positively increasing due to inadequate knowledge of vector biology. The current study is an attempt to uncover the vector biological aspects, focusing on the successful vector control interventions. This study was carried out in Anuradhapura district, Sri Lanka; a district with high disease prevalence of CL. Three sampling localities were selected; Thalawa, Padawiya and Wijayapura. A questioner and field studies were carried out in the sampling areas among CL patients to assess the effect of domestic environment characteristics on colonization of phlebotomine sand flies. Presence of decaying garbage, termite hills, manna grass (Glyceria sp.), water streams, unclear areas, wet soil areas, scrub jungles and gardening areas are the concerned characteristics for the present study. Field studies were conducted every month for seven months continuously. In every visit, Phlebotomine sand fly samples were collected from the study sites mentioned above using yellow sticky trap method. Increment of the mean number of sand fly population alongwith the increment of the number of domestic characteristics was tested with the regression analysis.With the increment of supportive environmental characteristics, sand fly populations were increased linearly (P = 0.000) in each site. This relationship revealed that the maximum sand fly populations were recorded in the places with all the tested characteristics stated above. Accordingly, the surrounding characteristics of the domestic environment have a significant effect on the colonization of sand fly populations. Domestic characteristics such as decaying organic matter, wet soil, unclear areas and water streams around the living environment show higher contribution to the colonization of sand flies. In conclusion, characteristics of the domestic environments have effect on the colonization of sand flies. Increment of the supportive domestic characters intensifies the colonization of sand flies.
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    Influence of humidity and temperature variation of natural breeding sites on abundance of Leishmaniasis vector Phlebotomus argentipes population in Anuradhapura District
    (Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Nayakarathna, N.M.N.G.; Ganehiarachchi, G.A.S.M.; Rajapakse, R.P.V.J.; Jayanetti, S.R.
    Cutaneous leishmaniasis (CL) is an endemic public health problem in Sri Lanka. Leishmania donovani is the suspected causative agent of the disease and this parasite is transmitted by a dipteran fly species; Phlebotomus argentipes. Studies on vector behavioral and ecological aspects, although important for better understanding of disease transmission, are still limited. The present study is an attempt to uncover the vector ecological aspects focusing on the successful vector control interventions. This study is being carried out in Anuradhapura district, Sri Lanka; where there is a high disease prevalence of CL. Three sampling sites; Thalawa, Wijayapura and Padawiya were selected. Adult sand flies were collected monthly over a six months duration using CDC light traps (5) and yellow sticky traps (30). In the meantime, relative humidity and air temperature were measured using hygrometer and thermometer in each site. The collected sand flies were identified up to the species level using standard keys. Percentage composition of each of the species was calculated. Temporal variations of primary vector, Phlebotomus argentipes along with the dynamics of temperature and relative humidity was determined using regression analysis. Phlebotomus argentipes was the dominant sand fly species found in the study sites. The percentage composition of the primary vector exhibited a variation during the study period and maximum percentage composition was recorded during May and June, 2016. The relationship between percentage composition of Ph.argentipes versus mean temperature was significant (P = 0.000, R2 = 97.7%) and elevated percentage composition were recorded under lower temperature. Further, percentage composition of Ph.argentipes exhibited an increasing trend with higher humidity levels (P = 0.000, R2= 98.4%). In conclusion, the primary vector populations of leishmaniasis are increased with lower temperature and higher humidity. As such, this relationship will helpful to predict the variation of vector population with the changes of ecological parameters and finally a successful vector management strategy can be implemented with the thorough knowledge of its life history parameters and behavioral pattern.