Background: Hepatitis B (HB) infections are a global public health concern, which carry high morbidity and mortality. Immunization is the safe and effective intervention to prevent transmission. Currently, the Hepatitis B vaccine is given to children at two, four and six months of age in Sri Lanka. However, the capability of this regimen in providing long term protection up to adolescence and beyond remains a concern. The current study was conducted to assess the HB immune status of children, ten years after vaccination during infancy. Methods: Antibody status of 150 children who received HB vaccine at two, four and six months of age was assessed 10 years after the last dose of vaccination. Some of these children had received liquid monovalent HB vaccine, while others were vaccinated with the Hexavalent vaccine. Children with HB antibody levels below the protective level were given a booster dose of monovalent recombinant HB vaccine, and antibody levels were reassessed in one month. Results: At the initial assessment, 128 children (85%) had protective levels of antibodies. Type of vaccine and gender had no significant effect on the prevalence of HB antibody levels (p>0.05). All children who received the booster dose developed protective levels of antibodies. Conclusions: Most of the children immunized against HB during infancy maintain protective antibody levels at 10 years of age. Children with antibody levels below protective levels produced a rapid anamnestic response following a booster dose.

The COVID-19 pandemic created numerous issues, particularly in Southeast Asia, and the recovery needs strong actions with new economic paths. The Sri Lankan government is also trying to help those who have lost their sources of income. Involving with the trade of medical and aromatic plants (MAPs) bearing unique medical properties will be important in that aspect. Extracted and isolated some secondary metabolites from plants developed life-saving medicine, flavonoids, repellents, cosmetics, and scents with enormous economic potential. India, China, and other Asian countries dominate the global MAP trade. However, Sri Lanka is yet to enter the global MAP market by utilising its abundant plant life. Determining rural communities’ willingness to participate in such programmes is crucial. The same authors identified 127 lesser-known potential MAPs as insect repellents by interviewing traditional ayurveda practitioners and subject experts. The current study investigated the willingness of the rural sector in six districts in Sri Lanka (Matara, Rathnapura, Kurunegala, Badulla, Hambanthota, and Batticaloa) using a structured questionnaire survey for 480 households. Cinnamomum verum, Citrus aurantifolia, C. sinensis, C. reticulata, Aegle marmelos, and Ocimum tenuiflorum Sub-type Rama were the most abundant top five plant species. The questionnaire also sought information on respondents' demographics, the availability of agronomic plants, MAPs, in their homegardens and their willingness to cultivate and supply medicinal plants. Binomial logistic regression was used to determine the effects of the respondent’s district, gender, age, education, total family revenue, availability of agronomic crops, land space available for the cultivation of MAPs, number of non-income-generating family members, members contribute to agriculture, external employees recruited as labourers. Hosmer-Lemeshow test indicated that the model reasonably fits with the data (p=0.77). In this case, district (p<0.05) and gender (p<0.05) were statistically significant while the other variables were not. Compared to Badulla District, the odds of willingness to grow and supply MAPs are approximately five times greater in Batticaloa District, four times greater in Hambantota, Kurunegala, and Matara districts and three times greater in Rathnapura District. Subsequently, the odds of the willingness of males to grow and supply MAPs was greater than females. Finally, it can be concluded that encouraging MAPs cultivation in rural areas will benefit post-pandemic populations while facilitating global trade, which is expected to reach USD 5 trillion by 2050. Keywords: Medicinal aromatic plants, Bioeconomy, Post-pandemic economic future, Rural economy, Indigenous knowledge

Background: Mosquitoes borne diseases have become a major health issue in Sri Lanka. Regardless of the high diversity of medically important mosquitoes, in depth studies that attempt to investigate their diversity and abundance are limited in Sri Lanka. Lentic water bodies that are largely associated with lotic aquatic systems such as rock pools, sand pools, mud pools, provide ideal breeding grounds for such mosquitoes, aggravating the risk imposed by such vectors. Therefore, the current study evaluated the diversity and abundance of medically important mosquitoes, which is of paramount importance for successful vector control programs. Methods and materials: The present study was conducted at 20 sentinel sites located in the Daduru Oya river basin located in the District of Kurunagala from November, 2018 to April, 2019. Different medically important mosquitoes present in potential lentic water habitats were collected using standard dipping and siphoning methods at monthly intervals. Collected larvae were microscopically identified using taxonomic keys. Results: A total of 158 rock pools and sand pools were monitored along the river basins. A total of 542 larvae belonging to four genera, namely, Aedes (10.68%), Anopheles (53.84%), Culex (34.33%) and Aedeomyia (1.15%) were found in the river basin. An. culicifacies (35.60%), the primary vector malaria in Sri Lanka, was the most prominent mosquito species, followed by Cu. gelidus (23.80%), a major vector of Japanese encephalitis. Cu. quinquefasciatus (9.04%), the vector of Filarisis and Cu. tritaeniorhynchus (2.76%), Cu. pseudovishnui (2.58%) and Cu. vishnui (4.42%) which are considered as major vectors of Japanese encephalitis were also found as medically important vectors. Relatively lower levels of Aedes vittatus (1.29%) and Aedeomyia catasticta (35.60%) were recorded from rock pools, which are not of any proven medical importance in Sri Lanka. The abundance of mosquito species differed significantly throughout the study period (p < 0.05 at 95% level of confidence) as suggested by the statistics of Chi square test. Conclusion: A higher abundance level of medically important vector mosquitoes were found during the study, suggesting that routine entomological surveillance is important especially since the primary vectors of malaria, Japanese encephalitis and Filarisis were recorded.

Background & objectives: Understanding the effect of biotic and abiotic factors on the biology and ecology of immature stages of anopheline larvae is very important in controlling malaria vector mosquitoes. Therefore, this study was focused on the monitoring of ecological factors affecting the distribution, dynamics, and density of malaria vector mosquitoes in the District of Trincomalee, Sri Lanka. Methods: Permanent and temporary breeding habitats were identified and selected from five possible malaria sensitive sites in the district of Trincomalee. Anopheles larvae and macro-invertebrates were collected using standard methods for 16 months (from October 2013 to January 2015) and they were identified microscopically. Eight physico-chemical parameters of the breeding habitats were measured. Results: Overall, a total of 4815 anopheline larvae belonging to 13 species were collected from 3,12,764 dips from 18 permanent and temporary breeding habitats. The abundance of anopheline larvae showed a significant positive correlation (p <0.05) with physico-chemical parameters in breeding habitats, such as temperature, dissolved oxygen, and turbidity. A total of 35 macro-invertebrate taxa were collected from the anopheline mosquito breeding habitats. Interpretation & conclusion: This study represents the first systematic update of water quality parameters, macro-invertebrate communities associated with Anopheles mosquito oviposition sites in the District of Trincomalee, Sri Lanka. Rainfall intensity and wind speed are critical meteorological factors for the distribution and abundance of malaria vectors. Knowledge generated on the ecology of Anopheles mosquitoes will help to eliminate malaria vectors in the country.

Malaria is one of the most widespread Vector-BorneDiseases (VBDs) in the world causing serious losses to the health and economy. Out of many factors, meteorological parameters effects on malaria distribution significantly. Conditions including higher temperature, lower relative humidity and higher wind velocity are found to be affecting on mosquito oviposition, propagation and survival. In Sri Lanka, Batticaloawas considered as one of the malaria endemicdistrictsduring recentpast. Control and effective management in these areas had been difficult due to the lack of reliable data, human resource and the deterioration of the infrastructure caused by years of armed conflict. This study was carried out to identify the relationships exist between different malaria vectors and meteorological parameters in the district of Batticaloa.Entomological surveillance was carried out in three potential malaria sensitive areas (Vakarai, Vakaneri and Mandur) with a radius of 20km in the district of Batticaloa from April 2013 to July 2014. Adult mosquito samples were collected monthly by WHO standard method; Cattle Baited Net Collection (CBNT). Monthly meteorological parameters (T: mean temperature, RF: total rainfall, WS: wind speed and RH: Relative humidity) during the study period were also collected from the Department of Meteorology. Data were analyzed using SPSS version 15.0. Pearson’s correlation coefficients (r) at 0.05 probability were used to investigate the relationships among meteorological variables of the current month along with lag time period of two months and vector densities. The most dominant mosquito species in the area was An. subpictuswith a relative abundance of 31.56% while An. nigerrimuswas the second highest (21.22%). Significant relationships were only observed with RH and WS where, An. nigerrimus showed a negative moderate relationship (r=0.372; p=0.03) while An. subpictus showed a positive relationship (r= 0.375; p=0.029) with RH. In addition, An. subpictusalsoshowed a negative relationship with one month lagged time of WS. The findings of the study reveal that the relationships that exist between the vector and the meteorological parameters are complicated and unpredictable. Neither patterns nor consistencies were observed in these relationships. The adaptation of vector and the influence of other environmental and anthropological factors on the vector mosquito could be the reason for this behaviour.Keywords:Malaria, Vector, Abundance, Relative humidity, Wind speed

Background: In special circumstances, establishing public private partnerships for malaria elimination may achieve targets faster than the state sector acting by itself. Following the end of the separatist war in Sri Lanka in 2009, the Anti Malaria Campaign (AMC) of Sri Lanka intensified malaria surveillance jointly with a private sector partner, Tropical and Environmental Diseases and Health Associates Private Limited (TEDHA) with a view to achieving malaria elimination targets by 2014. Methods: This is a case study on how public private partnerships can be effectively utilized to achieve malaria elimination goals. TEDHA established 50 Malaria Diagnostic Laboratories and 17 entomology surveillance sentinel sites in consultation with the AMC in areas difficult to access by government officials (five districts in two provinces affected by war). Results: TEDHA screened 994,448 individuals for malaria, of which 243,867 were screened at mobile malaria clinics as compared to 1,102,054 screened by the AMC. Nine malaria positives were diagnosed by TEDHA, while the AMC diagnosed 103 malaria cases in the same districts in parallel. Over 13,000 entomological activity days were completed. Relevant information was shared with AMC and the data recorded in the health information system. Conclusions: A successful public-private partnership model for malaria elimination was initiated at a time when the health system was in disarray in war ravaged areas of Sri Lanka. This ensured a high annual blood examination rate and screening of vulnerable people in receptive areas. These were important for certification of malaria-free status which Sri Lanka eventually received in 2016.

BACKGROUND:Leptospirosis is an important emerging infectious disease in Sri Lanka. Rats are the most important reservoir of Leptospira but domestic and wild mammals may also act as important maintenance or accidental hosts. In Sri Lanka, knowledge of reservoir animals of leptospires is poor. The objective of this study was to identify potential reservoir animals of Leptospira in the District of Gampaha, Sri Lanka.FINDINGS:Blood and kidney samples were collected from 38 rodents and mid-stream urine samples were randomly collected from 45 cattle and five buffaloes in the District of Gampaha. Kidney and urine samples were tested by real-time polymerase chain reaction (PCR) and serum samples were tested by the microscopic agglutination test (MAT). Of the 38 rodent kidney samples, 11% (4/38) were positive by real-time PCR. The prevalence of leptospiral carriage was 11% (3/26) and 8% (1/12) in female and male rodents, respectively. Three rodent serum samples were positive by MAT. Of the 50 cattle/buffalo urine samples tested, 10% (5/50) were positive by real-time PCR. The prevalence of leptospiral carriage was 9% (4/45) and 20% (1/5) in cattle and buffaloes, respectively.CONCLUSION:Results of PCR and MAT showed that Leptospira were present in a significant proportion of the rodents and farm animals tested in this study and suggest that these (semi-) domestic animals form an infection reservoir for Leptospira. Therefore, there is a potential zoonotic risk to public health, most notably to farmers in this area.

Leptospirosis has a major impact on health in Sri Lanka but is probably grossly under-recognized due to difficulties in clinical diagnosis and lack of diagnostic laboratory services. The objective of this study was to establish and evaluate a SYBR Green-based real-time Polymerase Chain Reaction (rt-PCR) assay for early, rapid and definitive laboratory diagnosis of leptospirosis in Sri Lanka. The rt-PCR assay was established and analytical specificity and sensitivity were determined using reference DNA samples. Evaluation of the assay for diagnosis of clinical samples was performed using two panels of serum samples obtained from 111 clinically suspected adult patients. Patients were confirmed as leptospirosis (n = 65) and non-leptospirosis (n = 30) by the Patoc - MAT. Other 16 samples gave ambiguous results. The analytical sensitivity of the rt-PCR was approximately 60 genome copies and no cross-reactivity was observed with saprophytic Leptospira spp. and other pathogenic microorganisms. Based on confirmation with Patoc-MAT on paired samples this corresponds to a diagnostic sensitivity and specificity of 67.7% (44/65) and 90.0% (27/30), respectively. This study showed that rt-PCR has the potential to facilitate rapid and definitive diagnosis of leptospirosis during early phase of infection in Sri Lanka.

Leptospirosis is a zoonostic infectious disease, caused by a pathogenic species of the Genus Leptospira. In recent years, a markedly increased number of leptospirosis cases have been reported in the District of Gampaha, in the Western Province of Sri Lanka. Typically, the risk of the disease in the district is seasonal with a small spike occurs in March to May and a large spike occurs during October to December. Objectives of this study were to analyze spatial and seasonal patterns of human leptospirosis and to predict the leptospirosis epidemic trend in the District of Gampaha, Sri Lanka. All Divisional Secretariats (DS) of the district of Gampaha were selected for the study. Epidemiological data were obtained from the Regional Epidemiological Unit, Gampaha. The leptospirosis cases were georeferenced according to DS in where these cases were reported. The cumulative incidence and the fatality were calculated for each DS. Of the georeferenced data, highest mean (±S.E.) of number of leptospirosis cases (72.60 ±15.54) were observed from DS of Mirigama. The highest mean cumulative incidence (4.97±1.10) and case fatality rate (3.88±2.42) were observed from DS of Divulapitiya and Katana respectively. According to past 10 years data on leptospirosis, highest mean numbers of leptospirosis cases were reported in March (51.00±12.99) and November (56.80±8.27). A predictive model for clinically confirmed human leptospirosis was designed for the district by using TSA package of the statistical software R. This study provides an evidence base for reducing disease burden by improving the understanding of the dynamic patterns of the disease in the District of Gampaha, Sri Lanka.

Conference Abstract, 2nd Pan Asian Conference on Haemoglobinopathies and Rare Anaemias, 26-27 September 2015, Ha Noi, Vietnam

Chikungunya fever swept across many South and South-east Asian countries, following extensive outbreaks in the Indian Ocean Islands in 2005. However, molecular epidemiological data to explain the recent spread and evolution of Chikungunya virus (CHIKV) in the Asian region are still limited. This study describes the genetic Characteristics and evolutionary relationships of CHIKV strains that emerged in Sri Lanka and Singapore during 2006-2008. The viruses isolated in Singapore also included those imported from the Maldives (n=1), India (n=2) and Malaysia (n=31). All analysed strains belonged to the East, Central and South African (ECSA) lineage and were evolutionarily more related to Indian than to Indian Ocean Islands strains. Unique genetic characteristics revealed five genetically distinct subpopulations of CHIKV in Sri Lanka and Singapore, which were likely to have emerged through multiple, independent introductions. The evolutionary network based on E1 gene sequences indicated the acquisition of an alanine to valine 226 substitution (E1-A226V) by virus strains of the Indian sublineage as a key evolutionary event that contributed to the transmission and spatial distribution of CHIKV in the region. The E1-A226V substitution was found in 95.7 % (133/139) of analysed isolates in 2008, highlighting the widespread establishment of mutated CHIKV strains in Sri Lanka, Singapore and Malaysia. As the E1-A226V substitution is known to enhance the transmissibility of CHIKV by Aedes albopictus mosquitoes, this observation has important implications for the design of vector control strategies to fight the virus in regions at risk of chikungunya fever.