Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item The use of recombinant K39, KMP11, and crude antigen-based indirect ELISA as a serological diagnostic tool and a measure of exposure for cutaneous leishmaniasis in Sri Lanka(Springer International, 2024) Karunathilake, C.; Alles, N.; Dewasurendra, R.; Weerasinghe, I.; Chandrasiri, N.; Piyasiri, S.B.; Samaranayake, N.; Silva, H.; Manamperi, N.; Karunaweera, N.Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani, a parasite widely known to cause visceral leishmaniasis. Despite the fact that CL is not generally believed to elicit serological immune responses, recent studies show the presence of antibody responses against this atypical form of CL. This study assesses the potential of using recombinant K39 (rK39), KMP11, and crude parasite antigen-based indirect ELISAs as serological diagnostic tools and measures of exposure for CL in Sri Lanka. The study used serum samples from confirmed CL patients (n = 266) and apparently healthy individuals from endemic settings (n = 411). Serum samples from individuals residing in non-endemic areas were used as negative controls. In-house indirect ELISAs were optimized and validated for recombinant antigens. Previously validated crude parasite extract-based indirect ELISA was performed for comparison. The statistical analyses were performed using SPSS v26.0. The rK39 (sensitivity = 71.2%, specificity = 64%) and KMP11 (sensitivity = 79.2%, specificity = 71.4%) based indirect ELISA were shown to be less suitable for the diagnosis of CL, while crude parasite extract-based indirect ELISA (sensitivity = 82.4%, specificity = 85.7%) might be a better method of diagnosis. All 03 ELISAs seemed to be good methods as measures of exposure since correlations were observed between the seropositivity of all 03 ELISAs (rK39: p = 0.037, KMP11: p = 0.007, CrudeAg: p = 0.000) with provincial case incidences. The findings will be important in identifying the disease hotspots in order to design the control measures for CL induced by L. donovani in Sri Lanka.Item The establishment of a population-specific reference value for the ruler drop test for the clinical assessment of reaction time(Elsevier, 2023) Rajapaksha, S.; Kitulwatte, I.; Senarathne, U.; Edirisinghe, A.; Perera, P.BACKGROUND: Reaction time (RT) is the interval between a stimulus and an appropriate voluntary response in an individual. Alcohol is known to result in delayed RT. In Sri Lanka, an alleged drunken driver is legally subjected to a medico-legal examination to confirm or exclude impairment. The guideline for examining a drunk person in Sri Lanka includes the ruler drop test (RDT) as a test of RT. RDT is a simple test of visual reaction time in which the subject attempts to stop a falling ruler, and the height fallen is used to determine the time taken to react to the event. However, a formal study has yet to be carried out to establish population-specific reference values to interpret RDT results. METHODS: A cross-sectional descriptive study was conducted using 903 adults ≥18 years. A nonparametric approach was applied for deriving the reference values based on an inter-percentile interval. RESULTS: The study population consisted of 56.6% females, and the mean age of the participants was 41.6 years. Most (95%) of the study population could catch the ruler at or less than 40.0 cm of average height. The average height on RDT increased from younger to older age groups. However, subgrouping based on other variables, including sex, age, and alcohol consumption, did not show any statistically significant difference. CONCLUSIONS: The population-specific cut-off limit to identify alcohol intoxication by RDT in a Sri Lankan adult is 'average height' >40 cm.Item Double-trouble: A rare case of co-infection with melioidosis and leptospirosis from Sri Lanka(Sage, 2023) Gunasena, J.B.; de Silva, S.T.Melioidosis and leptospirosis are two emerging tropical infections that share somewhat similar clinical manifestations but require different methods of management. A 59-year-old farmer presented to a tertiary care hospital with an acute febrile illness associated with arthralgia, myalgia and jaundice, complicated by oliguric acute kidney injury and pulmonary haemorrhage. Treatment was initiated for complicated leptospirosis but with poor response. Blood culture was positive for Burkholderia pseudomallei and microscopic agglutination test (MAT) for leptospirosis was positive at the highest titres of 1:2560, confirming a co-infection of leptospirosis and melioidosis. The patient made a complete recovery with therapeutic plasma exchange (TPE), intermittent haemodialysis and intravenous (IV) antibiotics. Similar environmental conditions harbour melioidosis and leptospirosis, making co-infection a very real possibility. Co-infection should be suspected in patients from endemic areas with water and soil exposure. Using two antibiotics to cover both pathogens effectively is prudent. IV penicillin with IV ceftazidime is one such effective combination.Item Community perceptions on intimate partner violence: A qualitative study from Sri Lanka(SAGE Publications, 2023) Reyal, H.P.; Perera, M.N.; Guruge, D.Although plenty of research is conducted to explore the causes of intimate partner violence (IPV), findings are inadequate about the community members' perceptions on IPV. This qualitative study was conducted in a health administrative area of Sri Lanka to explore IPV as perceived by community members in terms of what is IPV, what causes IPV, and what are the responses to prevent IPV. Five focus group discussions and 11 in-depth interviews were conducted with 34 women and eight men. Data were thematically analyzed, and a model on community perception of IPV was developed. It incorporated the individual, relationship, community, and societal levels of the existing ecological framework on causes of interpersonal violence. Perceived apparent and underlying determinants were operating directly and indirectly with complex interactions for the occurrence and continuation of IPV. Pathways of preventing or responding to IPV were identified. Findings on determinants can be incorporated into IPV interventions.Item Time series analysis of leishmaniasis incidence in Sri Lanka: evidence for humidity-associated fluctuations(Springer Verlag, 2023) Wijerathna, T.; Gunathilaka, N.Leishmaniasis is a vector-borne disease of which the transmission is highly influenced by climatic factors, whereas the nature and magnitude differ between geographical regions. The effects of climatic variables on leishmaniasis in Sri Lanka are poorly investigated. The present study focused on time-series analysis of leishmaniasis cases reported from Sri Lanka with selected climatic variables. Variance stabilized time series of leishmaniasis patients of entire Sri Lanka and major districts from 2014 to 2018 was fitted to autoregressive integrated moving average (ARIMA) models. All the possible models were generated by assigning different values for autoregression and moving average terms using a function written in R statistical program. The top ten models with the lowest Akaike information criterion (AIC) values were selected by writing another function. These models were further evaluated using RMSE and MAPE error parameters to select the optimal model for each area. Cross-autocorrelation analyses were performed to assess the associations between climate and the leishmaniasis incidence. Most associated lags of each variable were integrated into the optimal models to determine the true effects imposed. The optimal models varied depending on the area. SARIMA (0,1,1) (1,0,0)12 was optimal for the country level. All the forecasts were within the 95% confidence intervals. Humidity was the most notable factor associated with leishmaniasis, which could be attributed to the positive impacts on sand fly activity. Rainfall showed a negative impact probably as a result of flooding of sand fly larval habitats. The ARIMA-based models performed well for the prediction of leishmaniasis in the short term.Item The epidemiological trend of cutaneous leishmaniasis in Kegalle district, Sri Lanka: A newly established disease focus and assessment of bioclimatic suitability for disease establishment using ecological niche modelling(Elsevier, 2023) Wijerathna, T.; Wickramasinghe, K.; Gunathilaka, N.; Perera, A.; Bandara, S.Cutaneous leishmaniasis is prevalent in Sri Lanka since 1992. It remains as a health issue with increasing numbers and spreading from endemic to non-endemic areas in the county. Kegalle district is a new disease focus, which notified the first case in 2016. However, there is no documented evidence of the vector distribution, abundance and potential risk factors in this district. Two Medical Officer of Health (MOH) areas (Rambukkana and Warakapola) that had reported the highest numbers of cases in the Kagalle district was selected and recorded cases (2016-2020) were obtained. The patients were visited and socio-economic, demographic, environmental and awareness-related information was collected using an interviewer-administered questionnaire. Entomological surveys were conducted from July 2019- July 2020 using three standard entomological techniques. Bioclimatic suitability for the disease transmission was evaluated using ecological niche modelling. A total of 107 patients were reported from both MOH areas and 88 were recruited for the study. The study showed that leishmaniasis in the Kegalle district progressed to an outbreak level within 3 years after reporting the first case. School students (n = 22, 25%, P < 0.05) and individuals between 11 and 20 years of age (n = 33, 37.5%, P<0.05) were identified as the main risk groups, while the presence of composting sites (n = 65, 73.9%, P < 0.05), abandoned lands (n = 63, 71.6%, P < 0.05) in the surrounding and suboptimal (dark or normal) lighting conditions (n = 87, 98.8%, P < 0.05) in the house were identified as main risk factors. Areas closer to the adjacent district (Kurunegala), which is a known endemic district for leishmaniasis indicated a high probability (0.3-0.5) for disease transmission. Sergentomyia zeylanica (n = 164, 56.94%), was identified as the predominant sand fly species followed by Phlebotomus argentipes (n = 121, 42.01%), Sergentomyia babu insularis (n = 2, 0.69%) and Sergentomyia punjabensis (n = 1, 0.35%). Phlebotomus argentipes was captured mostly for outdoor resting sites and S. zeylanica was recoded from both indoor and outdoor. The presence of vectors that can transmit leishmaniasis in these areas along with the potential risk factors could increase the transmission risk and disease establishment in new areas that are ecologically favourable for disease transmission. Therefore, vector control entities should undertake immediate measures to stop spreading the disease into new areas.Item Susceptibility to malaria during the prevention of re-establishment phase in Sri Lanka(BioMed Central, 2022) Jeevatharan, H.; Wickremasinghe, R.BACKGROUND: Sri Lanka eliminated malaria in November 2012 and was certified malaria-free by the World Health Organization (WHO) in September 2016 but is facing a challenge to prevent re-establishment of malaria. Influx of travellers from malarious countries and the presence of malaria vectors in formerly endemic areas make the country both receptive and vulnerable. Susceptibility to malaria, the predisposition of populations to be infected by malaria parasites, is influenced by biologic and generic factors such as the age-sex composition, socio economic status, and the migration history of the population. The aim of this study was to assess susceptibility to malaria during the prevention of re-establishment phase in Sri Lanka. METHODS: A national survey was conducted among 3454 households. A multistage cluster sampling technique was used to select the households. Susceptibility was assessed based on pre-defined variables by interviewing heads of households using an interviewer-administered questionnaire. Basic socio-demographic information, travel history, history of fever and past malaria infections in the preceding three years were collected. Data were analysed using SPSS version 20 package. RESULTS: The percentage of the population who had been overseas within the last 3 years in the urban sector (4.5%, n = 99) was higher than that of the rural (2.8%, n = 288) and estate sectors (0.2%, n = 2) (p < 0.001); it also declined with the wealth index up to the 4th quintile with a slight rise in the 5th quintile (p < 0.001). The likelihood of travel overseas was 1.75 times (95% CI: 1.38-2.22) higher for urban residents as compared rural estate residents; it was 1.46 times (95% CI: 1.16-1.92) higher for persons from the upper wealth index quintile as compared to persons from the 1st and 2nd quintiles after controlling for sex, age and area of residence. 177 persons had fever within the past 2 weeks of the survey. There was no association between presence of fever within the last 2 weeks and sector or travel abroad. CONCLUSIONS: Urban residents, upper socioeconomic class persons and males are more likely to travel overseas and bring the parasite into the country. Social vulnerability and risk of re-establishment of malaria can be assessed by combining susceptibility with resilience and receptivity.Item Young patients with colorectal cancer have poor survival in the first twenty months after operation and predictable survival in the medium and long-term: analysis of survival and prognostic markers(BioMed Central, 2010) Chan, K.K.; Dassanayake, B.; Deen, R.; Wickramarachchi, R.E.; Kumarage, S.K.; Samita, S.; Deen, K.I.OBJECTIVES: This study compares clinico-pathological features in young (<40 years) and older patients (>50 years) with colorectal cancer, survival in the young and the influence of pre-operative clinical and histological factors on survival. MATERIALS AND METHODS: A twelve-year prospective database of colorectal cancer was analysed. Fifty-three young patients were compared with forty-seven consecutive older patients over fifty years old. An analysis of survival was undertaken in young patients using Kaplan Meier graphs, non-parametric methods, Cox's Proportional Hazard Ratios and Weibull Hazard models. RESULTS: Young patients comprised 13.4 percent of 397 with colorectal cancer. Duration of symptoms and presentation in the young was similar to older patients (median, range; young patients; 6 months, 2 weeks to 2 years, older patients; 4 months, 4 weeks to 3 years, p > 0.05). In both groups, the majority presented without bowel obstruction (young--81%, older--94%). Cancer proximal to the splenic flexure was present more in young than in older patients. Synchronous cancers were found exclusively in the young. Mucinous tumours were seen in 16% of young and 4% of older patients (p < 0.05). Ninety-four percent of young cancer deaths were within 20 months of operation. At median follow up of 50 months in the young, overall survival was 70% and disease free survival 66%. American Joint Committee on Cancer (AJCC) stage 4 and use of pre-operative chemoradiation in rectal cancer was associated with poor survival in the young. CONCLUSION: If patients, who are less than 40 years old with colorectal cancer, survive twenty months after operation, the prognosis improves and their survival becomes predictable.Item Alpha thalassaemia and extended alpha globin genes in Sri Lanka(Elsevier-Academic Press, 2013) Suresh, S.; Fisher, C.; Ayyub, H.; Premawardhena, A.; Allen, A.; Perera, A.; Bandara, D.; Olivieri, N.; Weatherall, D.The α-globin genes were studied in nine families with unexplained hypochromic anaemia and in 167 patients with HbE β thalassaemia in Sri Lanka. As well as the common deletion forms of α(+) thalassaemia three families from an ethnic minority were found to carry a novel form of α(0) thalassaemia, one family carried a previously reported form of α(0) thalassaemia, --(THAI), and five families had different forms of non-deletional thalassaemia. The patients with HbE β thalassaemia who had co-inherited α thalassaemia all showed an extremely mild phenotype and reduced levels of HbF and there was a highly significant paucity of α(+) thalassaemia in these patients compared with the normal population. Extended α gene arrangements, including ααα, αααα and ααααα, occurred at a low frequency and were commoner in the more severe phenotypes of HbE β thalassaemia. As well as emphasising the ameliorating effect of α thalassaemia on HbE β thalassaemia the finding of a novel form of α(0) thalassaemia in an ethnic minority, together with an unexpected diversity of forms of non-deletion α thalassaemia in Sri Lanka, further emphasises the critical importance of micro-mapping populations for determining the frequency of clinically important forms of the disease.Item Evaluating spatiotemporal dynamics of snakebite in Sri Lanka: Monthly incidence mapping from a national representative survey sample(Public Library of Science, 2021) Ediriweera, D.S.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Jayamanne, S.F.; Murray, K.; Iwamura, T.; Isbister, G.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.; Diggle, P.J.BACKGROUND: Snakebite incidence shows both spatial and temporal variation. However, no study has evaluated spatiotemporal patterns of snakebites across a country or region in detail. We used a nationally representative population sample to evaluate spatiotemporal patterns of snakebite in Sri Lanka. METHODOLOGY: We conducted a community-based cross-sectional survey representing all nine provinces of Sri Lanka. We interviewed 165 665 people (0.8% of the national population), and snakebite events reported by the respondents were recorded. Sri Lanka is an agricultural country; its central, southern and western parts receive rain mainly from Southwest monsoon (May to September) and northern and eastern parts receive rain mainly from Northeast monsoon (November to February). We developed spatiotemporal models using multivariate Poisson process modelling to explain monthly snakebite and envenoming incidences in the country. These models were developed at the provincial level to explain local spatiotemporal patterns. PRINCIPAL FINDINGS: Snakebites and envenomings showed clear spatiotemporal patterns. Snakebite hotspots were found in North-Central, North-West, South-West and Eastern Sri Lanka. They exhibited biannual seasonal patterns except in South-Western inlands, which showed triannual seasonality. Envenoming hotspots were confined to North-Central, East and South-West parts of the country. Hotspots in North-Central regions showed triannual seasonal patterns and South-West regions had annual patterns. Hotspots remained persistent throughout the year in Eastern regions. The overall monthly snakebite and envenoming incidences in Sri Lanka were 39 (95%CI: 38-40) and 19 (95%CI: 13-30) per 100 000, respectively, translating into 110 000 (95%CI: 107 500-112 500) snakebites and 45 000 (95%CI: 32 000-73 000) envenomings in a calendar year. CONCLUSIONS/SIGNIFICANCE: This study provides information on community-based monthly incidence of snakebites and envenomings over the whole country. Thus, it provides useful insights into healthcare decision-making, such as, prioritizing locations to establish specialized centres for snakebite management and allocating resources based on risk assessments which take into account both location and season.