Characteristics of the initial dengue outbreaks in a region without dengue prior to mid-2009 in a dengue-endemic country.

INTRODUCTION: The present study evaluated the characteristics of the initial dengue outbreaks in the Jaffna peninsula, a region without dengue prior to mid-2009 in dengue-endemic Sri Lanka, a tropical island nation. METHODOLOGY: This is a cross-sectional study conducted using a total of 765 dengue patients' clinical data and samples collected from the Teaching Hospital, Jaffna during the initial dengue outbreaks. Clinical, non-specific, and specific virological laboratory characteristics including the platelet count, NS1 antigen, and anti-DENV IgM/IgG were evaluated as correlates of dengue virus (DENV) infection in the two initial outbreaks of 2009/2010 and 2011/2012 in Northern Sri Lanka. RESULTS: Firstly, affected age and clinical characteristics were significantly different between the outbreaks (p < 0.005). Secondly, NS1 antigen detection in patients with fever days < 5 was statistically significant (p < 0.005). Thirdly, platelet count, detection of NS1 antigen, and anti-DENV IgM/IgG profiles were adequate to diagnose 90% of the patients; hepatomegaly and platelet count of < 25,000/mm3 were identified as predictors of severe disease. Fourthly, secondary DENV infections were detected in the early stages of the illness in many patients. Finally, infecting DENV serotypes were different between the two outbreaks. CONCLUSIONS: Clinical and non-specific laboratory characteristics and the infecting DENV serotypes between the two initial outbreaks in Northern Sri Lanka were significantly different. NS1 antigen, anti-DENV IgM/IgG, and platelet counts were identified 90% of the dengue patients. Hepatomegaly and platelet count of < 25,000/mm3 were able to predict the disease severity in this study.

Saw-scaled viper envenoming complicated with acute myocardial infarction.

The saw-scaled viper (Echis carinatus) is considered to be a venomous snake which is especially seen in Northern Sri Lanka. Systemic manifestations are rare and reported complications include coagulopathy and renal impairment. The cardiac toxicity following snakebites is rare and cardiac involvement following the saw-scaled viper bites is extremely rare. Here, we describe a patient with acute myocardial infarction following systemic envenoming by saw-scaled viper in Northern Sri Lanka, which was successfully managed per ward protocol following national guidelines.

Reassessment of the prevalence of soil-transmitted helminth infections in Sri Lanka to enable a more focused control programme: a cross-sectional national school survey with spatial modelling.

BACKGROUND: In Sri Lanka, deworming programmes for soil-transmitted helminth infections became an integral part of school health in the 1960s, whereas routine antenatal deworming with mebendazole started in the 1980s. A 2003 national soil-transmitted helminth survey done among schoolchildren found an overall prevalence of 6·9%. In our study, we aimed to reassess the national prevalence of soil-transmitted helminth infections to enable implementation of a more focused control programme that targets smaller administrative areas at risk of continued transmission. METHODS: We did a cross-sectional, school-based, national survey using multistage stratified cluster sampling, covering all nine provinces as well as populations at high risk of soil-transmitted helminth infections living in urban slums and in plantation-sector communities. Our study population was children aged 5-7 years attending state schools. Faecal samples were collected and analysed with duplicate modified Kato-Katz smears. We modelled the risk of soil-transmitted helminth infection using generalised linear mixed-effects models, and we developed prevalence maps to enable informed decision making at the smallest health administrative level in the country. FINDINGS: Between Jan 23 and May 9, 2017, we recruited 5946 children from 130 schools; 4276 (71·9%) children provided a faecal sample for examination. National prevalence of soil-transmitted helminth infection was 0·97% (95% CI 0·63-1·48) among primary schoolchildren. Prevalence in the high-risk communities surveyed was higher than national prevalence: 2·73% (0·75-6·87) in urban slum communities and 9·02% (4·29-18·0) in plantation sector communities. Our prevalence maps showed that the lowest-level health administrative regions could be categorised into low risk (prevalence <1%), high risk (prevalence >10%), or intermediate risk (1-10%) areas. INTERPRETATION: Our survey findings indicate that the national prevalence of soil-transmitted helminth infection has continued to decline in Sri Lanka. On the basis of WHO guidelines, we recommend discontinuation of routine deworming in low-risk areas, continuation of annual deworming in high-risk areas, and deworming once every 2 years in intermediate-risk areas, for at least 4 years. FUNDING: Task Force for Global Health and WHO.

A surveillance system for lymphatic filariasis after its elimination in Sri Lanka.

Lymphatic filariasis (LF) has been declared eliminated in Sri Lanka in September 2016. To maintain elimination status, a surveillance system to detect hidden endemic foci or LF resurgence is of highest priority. In this paper, we have reported an investigation of LF transmission in Trincomalee district where a surveillance program was not carried out due to 30 years of civil unrest. Proposed surveillance system included, measurement of anti-filarial IgG4 in urine of schoolchildren in areas where LF transmission could exist and assessment of circulating filarial antigen (CFA) and microfilaria (mf) in all urine antibody positive schoolchildren, their family members and 10-15 neighbours of each urine antibody positive household. Spatial distribution of the anti-filarial antibody titers in urine in a high antibody suspected area was analyzed using GPS logger data. Among 2301 school children from 11 schools studied, 41 (1.8%) urine antibody positives were found. The antibody positive rates of the schools ranged between 0 and 4.0%. Nine of the 630 (1.4%) examined became positive for CFA but were negative for mf. Although there were no mf positives, positive CFA and antibody results indicated the existence of Wuchereria bancrofti in Trincomalee. Highest antibody titres in an area correlated with the prevalences of urine antibodies and CFA. Spatial analysis showed LF transmission foci. Therefore, a combination of the non-invasive methods, urine ELISA and GPS mapping, will be a new effective surveillance system to identify hidden LF transmission foci.

Leukotoxin of Bibersteinia trehalosi Contains a Unique Neutralizing Epitope, and a Non-Neutralizing Epitope Shared with Mannheimia haemolytica Leukotoxin.

Bibersteinia trehalosi and Mannheimia haemolytica, originally classified as Pasteurella haemolytica biotype T and biotype A, respectively, under Genus Pasteurella has now been placed under two different Genera, Bibersteinia and Mannheimia, based on DNA-DNA hybridization and 16S RNA studies. While M. haemolytica has been the predominant pathogen of pneumonia in ruminants, B. trehalosi is emerging as an important pathogen of ruminant pneumonia. Leukotoxin is the critical virulence factor of these two pathogens. While the leukotoxin of M. haemolytica has been well studied, the characterization of B. trehalosi leukotoxin has lagged behind. As the first step towards addressing this problem, we developed monoclonal antibodies (mAbs) against B. trehalosi leukotoxin and used them to characterize the leukotoxin epitopes. Two mAbs that recognized sequential epitopes on the leukotoxin were developed. One of them, AM113, neutralized B. trehalosi leukotoxin while the other, AM321, did not. The mAb AM113 revealed the existence of a neutralizing epitope on B. trehalosi leukotoxin that is not present on M. haemolytica leukotoxin. A previously developed mAb, MM601, revealed the presence of a neutralizing epitope on M. haemolytica leukotoxin that is not present on B. trehalosi leukotoxin. The mAb AM321 recognized a non-neutralizing epitope shared by the leukotoxins of B. trehalosi and M. haemolytica. The mAb AM113 should pave the way for mapping the leukotoxin-neutralizing epitope on B. trehalosi leukotoxin and the development of subunit vaccines and/or virus-vectored vaccines against this economically important respiratory pathogen of ruminants.

Epidemiology and factors associated with amoebic liver abscess in northern Sri Lanka.

BACKGROUND: Clinically diagnosed amoebic liver abscess (ALA) caused by Entamoeba histolytica has been an important public health problem in Jaffna district, northern Sri Lanka for last three decades. In order to draw up a control strategy for elimination of this condition, knowledge of its epidemiology and factors associated with this condition in the local context is vital. METHODS: All clinically diagnosed ALA patients admitted to the Teaching Hospital, Jaffna during the study period were included in the study and the data were collected using an interviewer administered questionnaire. One hundred blood samples from randomly selected toddy (a local alcoholic drink consisting of the fermented sap of the Palmyrah palm) consumers and 200 toddy samples were collected. Toddy samples were cultured in Robinson's medium to establish the presence of Entamoeba histolytica in the sample. Climatic data and the total toddy sales in the district were obtained from the Meteorological and Excise Departments respectively. A sub group of randomly selected 100 patients were compared with 100 toddy consumers who were negative for E. histolytica antibody to explore the potential risk factors. RESULTS: Between July 2012 and July 2015, 346 of 367 ALA patients were enrolled in this study. Almost all patients (98.6%) were males with a history of heavy consumption of alcohol (100%). Almost all (94.2%) were within the age group 31-50 years. None of the cultured toddy samples grew E. histolytica. The monthly incidence of disease peaked in the dry season, matching the total toddy sales in the district. Age, type of alcohol and frequency of drinking were identified as potential risk factors whereas frequency of alcohol consumption and type of alcohol (consuming toddy and arrack) were identified as the independent risk factors. Moreover, the knowledge, attitude and practices towards ALA were poor among participants and the control group. CONCLUSIONS: Though the number of cases has declined in recent years, ALA still remains as an important public health problem in Jaffna district. The transmission route of E. histolytica leading to ALA has to be further explored. Moreover, greater awareness among the public who are at risk would be beneficial in order to eliminate the disease.

Amoebic liver abscess in northern Sri Lanka: first report of immunological and molecular confirmation of aetiology.

BACKGROUND: Since 1985, amoebic liver abscess (ALA) has been a public health problem in northern Sri Lanka. Clinicians arrive at a diagnosis based on clinical and ultrasonographic findings, which cannot differentiate pyogenic liver abscess (PLA) from ALA. As the treatment and outcome of the ALA and PLA differs, determining the etiological agent is crucial. METHODS: All clinically diagnosed ALA patients admitted to the Teaching Hospital (TH) in Jaffna during the study period were included and the clinical features, haematological parameters, and ultrasound scanning findings were obtained. Aspirated pus, blood, and faecal samples from patients were also collected. Pus and faeces were examined microscopically for amoebae. Pus was cultured in Robinson's medium for amoebae, and MacConkey and blood agar for bacterial growth. ELISA kits were used for immunodiagnosis of Entamoeba histolytica infection. DNA was extracted from selected pus samples and amplified using nested PCR and the purified product was sequenced. RESULTS: From July 2012 to July 2015, 346 of 367 clinically diagnosed ALA patients admitted to Jaffna Teaching Hospital were enrolled in this study. Almost all patients (98.6%) were males with a history of heavy alcohol consumption (100%). The main clinical features were fever (100%), right hypochodric pain (100%), tender hepatomegaly (90%) and intercostal tenderness (60%). Most patients had leukocytosis (86.7%), elevated ESR (85.8%) and elevated alkaline phosphatase (72.3%). Most of the abscesses were in the right lobe (85.3%) and solitary (76.3%) in nature. Among the 221 (63.87%) drained abscesses, 93.2% were chocolate brown in colour with the mean volume of 41.22 ± 1.16 ml. Only four pus samples (2%) were positive for amoeba by culture and the rest of the pus and faecal samples were negative microscopically and by culture. Furthermore, all pus samples were negative for bacterial growth. Antibody against E. histolytica (99.7%) and the E. histolytica antigen were detected in the pus samples (100%). Moreover, PCR and sequencing confirmed these results. CONCLUSION: To our knowledge, this is the first report from Sri Lanka that provides immunological and molecular confirmation that Entamoeba histolytica is a common cause of liver abscesses in the region.

Awareness and perceptions on prevention, first aid and treatment of snakebites among Sri Lankan farmers: a knowledge practice mismatch?

BACKGROUND: Snakebite is a global health problem associated with high morbidity and mortality. In Sri Lanka, snakebite is mainly an occupational health hazard associated with farming. Understanding awareness and perceptions in risk populations on the preventive measures, first aid and treatment for snakebite becomes pivotal in designing snakebite prevention and control programs. Using an investigator assisted self completed questionnaire, we assessed the awareness and perceptions of 176 part-time and full-time, Chena and paddy farmers from three dry zone districts of Sri Lanka where agriculture is the main economic activity. FINDINGS: High percentages of the participants were aware of practices that minimize snakebites in houses and outside, available treatments and most of the recommended first aid measures. Western medical treatment was preferred by the vast majority of the farmers over the traditional treatment. CONCLUSION: Some of the protective measures that the farmers were aware of are not practiced generally in Sri Lanka, suggesting a knowledge-practice mismatch. We suggest studies to understand the effects of socioeconomic and cultural determinants on snakebite prevention in Sri Lanka.

A simple intervention to prevent cutaneous larva migrans among devotees of the Nallur Temple in Jaffna, Sri Lanka.

BACKGROUND: A cross sectional study conducted during the annual festival at Nallur temple in Jaffna, Sri Lanka, in 2010, showed that the prevalence of cutaneous larva migrants (CLM) among the devotees who performed the side roll ritual was 58.2% (95%CI: 51.2%-65.0%). OBJECTIVE: To test the hypothesis that the deworming stray dogs around the temple premises effectively reduces the prevalence of CLM among devotees. METHODOLOGY/PRINCIPAL FINDINGS: All stray dogs (8) in the vicinity of the temple were treated, with mebendazole (100 mg) crushed and filled into sausages, 10 days before the commencement of festival in 2011. The same procedure was repeated a week later to ensure complete coverage. A cross-sectional study was conducted among 200 systematically selected devotees in August 2011 using an interviewer-administered questionnaire and the clinical examination of the skin. Baermann's technique was used for the recovery of nematode larvae from 40 soil samples collected from the temple premises. Ten samples of dog faeces collected from the same premises were also examined for nematode eggs. Prevalence of CLM among devotees in 2010 (Pre intervention) and 2011(Post intervention) were compared to test the hypothesis. Prevalence of CLM declined from 58% to 8% (Chi-square = 112.90, p<0.001) following the intervention. None of the subjects practiced new precautionary measures compared to the previous year. Soil and fecal samples were negative for parasites. CONCLUSIONS/SIGNIFICANCE: Regular dog deworming is an important and effective method for the prevention of CLM among the devotees doing side roll ritual and represents a pragmatic intervention that municipal authorities could perform on annual basis.

Cutaneous larva migrans among devotees of the Nallur temple in Jaffna, Sri Lanka.

BACKGROUND: Many cases of Cutaneous Larva Migrans (CLM) have been observed among devotees, during and immediately after the annual festival at the Nallur Hindu temple in Jaffna. OBJECTIVE: To ascertain the risk factors associated with infestation and devotees' knowledge and practices regarding the condition. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study using an interviewer-administered questionnaire and observation was conducted in August 2010. Out of 200 selected devotees 194(97%) responded. Soil and dog faecal samples were collected from the temple premises and examined for the presence of nematode larva and egg respectively. Among 194 male respondents, 58.2%(95% CI: 51.2%-65.0%) had lesions of CLM. One hundred and thirty (67%) respondents performed the ritual everyday; whereas 33% did so on special days. One hundred and twelve (57.7%) participants performed the ritual before 5.00am and remaining 42.3% performed after 5.00am. Among the participants, 77(36.7%) had the similar condition in previous years. One hundred and fifty seven (80.9%) were aware about this disease and 52(27%) devotees adopted some kind of precautionary measures. Bivariate analysis showed significant association between occurrence of CLM lesions and frequency of performing the ritual (p<0.001, OR-15.1; 95% CI:7.2-32.0), the timing of ritual performance (p = 0.022, OR-1.96; 95% CI:1.10-3.52), similar condition in previous year (p<0.001, OR-6.83; 95% CI: 3.39-13.76) and previous awareness of the condition (p = 0.005; OR-0.59;95% CI:0.43-0.82). Multivariate analysis showed that the frequency of ritual performance (OR-11.75; 95% CI 5.37-25.74) and similar conditions in previous years (OR-4.71; 95% CI: 2.14-10.39) were the independent risk factors. Two of the 20 soil samples were positive for the nematode larvae and three out of five dog faeces were positive for hookworm eggs. CONCLUSIONS/SIGNIFICANCE: Deworming the stray dogs around the temple premises combined with the awareness programs among the public may be the effective and feasible precautionary measures to control similar epidemics in future.