Browsing by Author "Gunathilaka, P.A.G.N."

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Awareness of Rickettsial Infections (Typhus Fever) in a High Endemic Community in Hambantota District, Sri Lanka
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Ashani, M.L.S.; Chandrasena, T.G.A.N.; Gunathilaka, P.A.G.N.; Premaratna, B.A.H.R.
Rickettsial infections are re-emerging in Sri Lanka with an average annual incidence of 1500 patients. Low awareness and the scarcity of proper diagnostic tools has resulted in delayed disease diagnosis and negligence towards the disease leading to extended morbidity in Sri Lanka. Community awareness of the disease is important for timely diagnosis and control. Hambantota district in Southern Province of Sri Lanka, which records the fourth highest incidence of typhus, was selected for the study. Households (n= 204) situated around index cases of typhus fevers were randomly selected for the survey. An interviewer-administered questionnaire was used to gather data on illness awareness (disease aetiology, symptoms, transmission, disease associations) by selecting a consenting representative from each household. Descriptive and inferential analysis of the data was carried out using SPSS IBM statistical software. Of the 204 interviewed, only one (0.5%) identified the illness as “typhus”. Majority identified the disease as “Peacock fever” (43.12%; n= 88) followed by “tick fever” (14.71%; n=30). It is interesting to note that 41.67% (n=85) of the households were not aware of the disease even though they are living in a disease endemic area. None were aware of the etiological agents of typhus fever. Among those with awareness, 65.55% (n=78), believed that infection was tick-borne and the vector ticks were harbored by peacocks. About 27.73% (n=33) believed that the transmission was directly from peacocks, followed by other birds (2.52%; n=3). Majority 82.35 %, (n=98) were unaware of symptomatology while only 1.77%, (n=14) recognized it only as a febrile illness and myalgia (4.20%; n=5). Of those who were aware, 73.95 %, (n=88) had received information through acquaintances, 25.21% (n=30) from health personnel and one through mass media. None were aware of preventive measures. The results of the present study highlight the lack of proper awareness of the disease condition, which may adversely impact on disease control efforts
Scrub Typhus, Its potential zoonotic hosts and vectors in Sri Lanka: A preliminary report
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Ashani, M.L.S.; Chandrasena, T.G.A.N.; Gunathilaka, P.A.G.N.; Premaratna, B.A.H.R.
Scrub typhus or tsutsugamushi disease is an acute febrile infectious disease endemic in the “tsutsugamushi triangle” of Southeast Asia, the Asian Pacific rim, and Northern Australia, with approximately one billion individuals at risk of infection. Currently one million new infections occur annually. The term scrub typhus is descriptive of the typical habitat endemic to the vector, although its existence is not limited to such niches. It is caused by a Gram-negative, obligate intracellular bacterium Orientia tsutsugamushi, of the Rickettsiaceae family, transmitted to humans following an accidental bite by an infected larval trombiculid mite commonly known as chiggers. Chiggers are a group of ectoparasites prevalent on a variety of mammals, mainly small mammals like rodents. Clinical cases of scrub typhus are documented in almost all ecological zones including both rural and urban Sri Lanka, as year-round sporadic cases or as outbreaks. However, the reservoir hosts in Sri Lanka and transmitting vector species are yet to be identified. Such knowledge is important for effective implementation of control measures of this re-emerging infection. Therefore, this study was designed to live capture small rodent/mammal hosts and identify chigger mite species present in the country. Traps designed to live capture small rodents/mammals were placed in peri-domestic areas of clinically confirmed scrub typhus patients in southern province, Sri Lanka. Traps baited with fried coconut were placed around residences and in pre-selected sites with scrubby vegetation and rodent burrows, one hour before sunset and were retrieved the next day morning. The captured animals were anaesthetized with ketamine/xylazine and inspected for the presence of vector mites. Collected mites were preserved in 70% alcohol and identified by microscopy using standard morphological keys. Collected data were analyzed using chi square test, MINITAB 17 statistical software. Rodents belonging to Rattus norvegicus (n=15; 56%), Rattus rattus (n= 10; 37%) and shrews of Suncus murinus (n=2, 7.4%) were captured during the study over 6 months and a total of 147 mites were isolated. Isolated chigger mites belonged to genus Leptotrombidium (n=90; 67%), Eutrombicula (n=31; 23%), Helenicula (n=24,17 %) and species Leptotrombidium lagone (n=2; 1.5 %). Majority were potential vectors for Orientia tsutsugamushi. It is noted that Rattus norvegicus harbored significantly more chigger mites (mean of 7 per individual; χ2 = 110.35; p <0.001] compared to other species captured. We are currently in the process of molecular speciation of sampled chigger mites and molecular detection of Orientia tsutsugamushi in collected mites in order to determine their vectorial potential.