Characterisation of cutaneous leishmaniasis in Matara district, southern Sri Lanka: evidence for case clustering

Abstract

Leishmaniasis is a neglected tropical disease transmitted by Phlebotomus spp. sand flies. Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani. Transmission patterns are different in Southern and Northern Sri Lanka. Current study examined the prevalence, risk factors and distribution of CL in Matara District, Southern Sri Lanka. Total of 2260 individuals from four District Secretariat divisions (DSDs) were screened by house to house surveys using an interviewer administered questionnaire. The study population had an age range of 1-90 years (median 5 43 + 17.31), low monthly income (v20 000 LKR, 52.8%) and a male to female ratio of 1 : 2. Thirty eight patients were diagnosed by light microscopy, culture and/or PCR with a disease prevalence of 1.68%. Spatial mapping provided evidence for significant case clustering, which tended to be more prominent with proximity to forest areas. The risk factors identified were un-plastered brick walls, absence or low usage of protective measures against insect bites, low income and excessive time (w4 hours/day) spent outdoors. However, exposure of limbs while outdoors, unawareness about the disease, type of occupation, common water source as the mode of water supply and presence of animal shelters within 200 m were not associated with the risk of acquiring the disease. Peri-domestic transmission is likely to contribute to the observed case clustering with all age groups at risk of acquiring the infection. Human behavioural habits coinciding with that of the vector, sand fly are likely to enable host-vector contact promoting its spread. Appropriate vector control measures, improvement of housing conditions, public education regarding preventive measures are required to contain the spread of disease.

Polymerase chain reaction detection of LeishmaniaDNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani

“…In this context, 1% SSS positive newly diagnosed CL case incidence was reported in a cross sectional study in a high CL endemic area in the north-central province of Sri Lanka ( Ranasinghe et al 2013 ), indicating the need for active case detection measures. A recent study described the successful application of a PCR method along with SSS and culture for active case detection in another CL endemic area in southern Sri Lanka ( Kariyawasam et al 2015 ). Furthermore, limited data on epidemiology show evidence of geographical overlap of cutaneous TB, leprosy, and CL in Sri Lanka ( Ranawaka et al 2010 , Yasaratne & Madegedara 2010 , MS Sri Lanka 2014 , 2015a ).…”

Literature review and a preliminary study on leishmaniasis to inform community awareness campaigns in Sri Lanka

“…Household's ownership of animals, the presence of animal shelters in the home compound, the frequency of visits to animal sheds and the type of roof were not found to have any significant effect on the risk of CL. 8 Another study with a sample size of 2260 done in the Matara district 16 showed a higher number of affected females (60.5%, p< 0.05) than males. They identified un-plastered brick walled houses (p<0.05) and excessive time (>4 hours/day) spent outdoors (P<0.05) as significant factors for CL.…”

“…Occupation, common water source as the mode of water supply and presence of animal shelters in their gardens within 200 m were not associated with the risk of acquiring the disease in this study. 16 In a cross sectional study done with 834 participants in Thalawa MOH, Anuradhapura district 19 , distance to paddy fields from the residencies of CL patients was significant (p=0.01) whereas distances to forest, marsh, scrub jungles, and water bodies were not. Contradictory findings were presented in another study conducted using 57 patients attending the Anuradhapura Teaching Hospital 20 , in which existence of scrub jungles around the residence or occupational places (p=0.003), presence of sandflies (p=0.021) and working outside for more than 6 hours per day (p=0.001) were significant.…”

“…Dickwella DS in the Matara district of southern Sri Lanka is "a notable hotspot for CL" as it has shown a concentration of CL cases. 16 This descriptive cross sectional study was conducted in the Dickwella DS division which consists of 48 GNDs.…”

Fatores de risco ambientais e socioeconômicos associados com a leishmaniose

“…In Mediterranean regions, cutaneous and visceral leishmaniasis are considered reemergent diseases due to vector adaptation to urban environments (Steffens 2010). In tropical and arid regions the transmission cycle of CL remains in rural, forest and peri-domestic areas, but the transmission cycle of VL presented an urban adaptation (Nasser et al 2009;Kariyawasam et al 2015). Socioeconomic conditions influence the incidence of both leishmaniasis worldwide.…”