Severe Dengue Epidemic, Sri Lanka, 2017.

In 2017, a dengue epidemic of unexpected magnitude occurred in Sri Lanka. A total of 186,101 suspected cases and 440 dengue-related deaths occurred. We conducted a comprehensive analysis of this epidemic by comparing national surveillance data for 2017 with data from the preceding 5 years. In all Sri Lanka districts, dengue incidence in 2017 increased significantly over incidence during the previous 5 years. Older schoolchildren and young adults were more clinically symptomatic than those at extremes of age. Limited virologic surveillance showed the dominant circulating variant was dengue virus type 2 cosmopolitan genotype in the most affected district. One quarter of total annual cases were reported 5 weeks after the southwest monsoon started. Changes in vector abundance were not predictive of the increased incidence. Direct government expenditures on dengue control activities in 2017 were US $12.7 million. The lessons learned from this outbreak are useful for other tropical nations facing increasing dengue incidence.

Risk prediction for severe disease and better diagnostic accuracy in early dengue infection; the Colombo dengue study.

BACKGROUND: A major challenge in dengue management in resource limited settings is the confirmation of diagnosis. Clinical features of dengue often overlap with other infections and molecular diagnostic tools are not readily accessible to clinicians at hospitals. In addition, the prediction of plasma leakage in dengue is also difficult. Hematocrit level and ultrasound scans (combined with clinical parameters) are helpful to detect plasma leakage once it has happened, not before. METHODS: Colombo Dengue Study (CDS) is a prospective cohort study of clinically suspected adult dengue patients recruited from the National hospital of Sri Lanka (within the first 3 days of fever) that aimed to a) identify clinical and basic laboratory test parameters to differentiate dengue from non-dengue fever, b) evaluate the comparative efficacy of loop-mediated isothermal amplification (LAMP) for dengue diagnosis (vs. NS1 antigen test and RT-qPCR) and c) identify early associations that are predictive of plasma leakage or severe dengue. The basic laboratory tests considered here included hematological parameters, serum biochemistry and inflammatory markers. RESULTS: Only 70% of clinically suspected patients were confirmed as having dengue by either the NS1 antigen test or RT-qPCR. On a Bayesian latent class model which assumes no "gold standard", LAMP performed equally or better than RT-qPCR and NS1 antigen test respectively. When confirmed dengue patients were compared with others, the earlier group had significantly lower lymphocyte counts and higher aspartate aminotransferase levels (AST) within the first 3 days of fever. Confirmed dengue patients with plasma leakage had a lower mean age and a higher median baseline AST level compared to those without plasma leakage (p < 0.05). CONCLUSION: Clinical suspicion overestimates the true number of dengue patients. RT-LAMP is a potentially useful low-cost diagnostic tool for dengue diagnosis. Confirmed dengue patients had significantly higher AST levels and lower lymphocyte counts in early disease compared to others. In confirmed dengue patients, younger age and a higher AST level in early infection were associated with subsequent plasma leakage.

Association of HLA class I and II genes with cutaneous leishmaniasis: a case control study from Sri Lanka and a systematic review.

BACKGROUND: The outcome of leishmaniasis is an interplay between Leishamania and the host. Identifying contributory host genetic factors is complicated by the variability in phenotype, ethnicity and parasite species. Leishmaniasis is caused exclusively by L. donovani in Sri Lanka with localized cutaneous leishmaniasis (LCL) being the predominant form. We report here an association study of human leucocyte antigen (HLA) class I and II genes with LCL in Sri Lanka, the first on HLA associations in cutaneous leishmaniasis in a South Asian population. METHODS: An existing DNA repository of 200 each of patients and controls was typed for HLA-DQ by PCR-SSP. Next generation sequencing-based typing for HLA-A, HLA-B and HLA-DRB1 alleles was done in a subset of 280 samples. Association tests were performed on 28,489 genotyped and imputed SNPs spanning a region of 1.4 Mb across the HLA genes. To compare our results with similar studies, we carried out a systematic review to document all HLA associations reported to-date for cutaneous and muco-cutaneous leishmaniasis. RESULTS: DRB1*04 DQB1*02 (P = 0.03; Pc = 0.09), DRB1*07 DQB1*02 (P = 0.03; Pc = 0.09) haplotypes were absent in patients. B*07 (P = 0.007; Pc = 0.13; OR = 0.36; 95 % CI = 0.17-0.77) allele and DRB1*15 DQB1*06 (P = 0.00; Pc < 0.01; OR = 0.3; 95 % CI = 0.2-.0.6) haplotype were over represented in controls and DRB1*15 (P = 0.002; Pc = 0.01) allele was over represented in patients. Two SNPs (rs281864595/rs1050517) in the antigen recognition region of HLA-B, comprised a haplotype more frequent in controls (P = 0.04). The alleles identified by the systematic review to predispose or to protect from cutaneous/mucocutaneous leishmaniasis remained highly heterogeneous in different populations studied. CONCLUSIONS: Our preliminary findings suggest a role for some class I and class II HLA genes in determining predisposition to LCL in this population which should be corroborated with further studies. The systematic review reiterates this need, as the purported susceptibility or protection gained by certain HLA alleles or haplotypes has rarely been independently verified.

Effects of modifying the World Health Organization standard operating procedures for malaria microscopy to improve surveillance in resource poor settings.

BACKGROUND: Individuals with fever are screened for malaria in specially-established malaria diagnostic laboratories set up in rural hospitals in the Northern and Eastern Provinces of Sri Lanka. Large numbers of blood smears negative for malaria parasites are being screened daily. Good quality smears are essential to maintain a high diagnostic competency among the technical staff. The modifications made to the World Health Organization (WHO) standard operating procedures to improve the quality of smears have been studied. METHODS: A blinded, controlled, interventional study was conducted in 22 intervention and 21 control malaria diagnostic laboratories. Changes were made to the WHO standard operating procedure protocols to prepare, stain and examine blood smears for malaria parasite detection which were implemented in intervention laboratories. These included wipe-cleaning slides, preparing both thick and thin smears on the same slide, reversing the order of collecting blood for thick and thin smears, dry fixing thick smear for 20-25 minutes under table lamp, polishing the edge of spreader slide with sand paper and fixing the thin smear with methanol if not stained within four hours. Parameters with respect to quality of the smear as per WHO criteria were studied using randomly selected slides, and time taken for the report to be issued was recorded in both groups before and after the intervention. RESULTS: There were no significant differences observed in the parameters studied at baseline between the two groups or pre and post intervention in the control group. In the intervention group streak formation in thin smears was reduced from 29.4% to 5.0%. The average fixing time of thick smears was reduced from 2.4 hours to 20 minutes. Inappropriate thickness of thick smears reduced from 18.3% to 1.5%. Overall quality of thick smears and thin smears increased from 76.1% to 98.0% and 81.7% to 87.0%, respectively. The quality of slides bearing both thick and thin smears increased from 60.0% to 87.0%. CONCLUSIONS: New protocols with amendments to the WHO standard technical procedures ensure that good quality blood smears are prepared rapidly to diagnose malaria and the time required to issue the reports was reduced.

Genetic polymorphisms associated with anti-malarial antibody levels in a low and unstable malaria transmission area in southern Sri Lanka.

BACKGROUND: The incidence of malaria in Sri Lanka has significantly declined in recent years. Similar trends were seen in Kataragama, a known malaria endemic location within the southern province of the country, over the past five years. This is a descriptive study of anti-malarial antibody levels and selected host genetic mutations in residents of Kataragama, under low malaria transmission conditions. METHODS: Sera were collected from 1,011 individuals residing in Kataragama and anti-malarial antibodies and total IgE levels were measured by a standardized ELISA technique. Host DNA was extracted and used for genotyping of selected SNPs in known genes associated with malaria. The antibody levels were analysed in relation to the past history of malaria (during past 10 years), age, sex, the location of residence within Kataragama and selected host genetic markers. RESULTS: A significant increase in antibodies against Plasmodium falciparum antigens AMA1, MSP2, NANP and Plasmodium vivax antigen MSP1 in individuals with past history of malaria were observed when compared to those who did not. A marked increase of anti-MSP1(Pf) and anti-AMA1(Pv) was also evident in individuals between 45-59 years (when compared to other age groups). Allele frequencies for two SNPs in genes that code for IL-13 and TRIM-5 were found to be significantly different between those who have experienced one or more malaria attacks within past 10 years and those who did not. When antibody levels were classified into a low-high binary trait, significant associations were found with four SNPs for anti-AMA1(Pf); two SNPs for anti-MSP1(Pf); eight SNPs for anti-NANP(Pf); three SNPs for anti-AMA1(Pv); seven SNPs for anti-MSP1(Pv); and nine SNPs for total IgE. Eleven of these SNPs with significant associations with anti-malarial antibody levels were found to be non-synonymous. CONCLUSIONS: Evidence is suggestive of an age-acquired immunity in this study population in spite of low malaria transmission levels. Several SNPs were in linkage disequilibrium and had a significant association with elevated antibody levels, suggesting that these host genetic mutations might have an individual or collective effect on inducing or/and maintaining high anti-malarial antibody levels.

Dengue and post-infection fatigue: findings from a prospective cohort-the Colombo Dengue Study.

BACKGROUND: Previous studies on post-infection fatigue in dengue are few but suggest that up to 25% of dengue patients may suffer from fatigue. This study aimed to evaluate the prevalence and associations of post-infection fatigue in dengue patients compared with non-dengue fever patients. METHODS: Post-infection fatigue and its demographic and clinical associations were assessed in adult dengue and non-dengue fever patients 2 months after the acute infection in a prospective cohort study in Sri Lanka. Fatigue at 2 months (primary endpoint) was assessed with the fatigue questionnaire as a dichotomous outcome based on a pre-recommended cut-off (score ≥4) and as the total score from the questionnaire (higher score indicates more fatigue). RESULTS: Of 260 patients, 158 had dengue and, of these, 51 (32%) had fatigue at 2 months. Risk was higher in dengue patients (vs non-dengue; relative risk [RR] 4.93 [95% confidence interval {CI} 2.3 to 10.4]) and more so in female dengue patients (vs male dengue patients; RR 2.45 [95% CI 1.24 to 4.86]). Severe dengue patients had a higher mean fatigue score (p=0.024). CONCLUSIONS: Post-infection fatigue is an underappreciated burden of this widely prevalent infection. Our findings are useful to triage patients at risk of fatigue for follow-up.

The 'hidden' burden of malaria: cognitive impairment following infection.

BACKGROUND: The burden of post-malaria cognitive impairment is often overlooked. Given the large number of infections occurring worldwide, the magnitude of the problem is likely to be substantial. The objectives of this paper are; (i) to assess the evidence on post malarial cognitive impairment or impact on school education; (ii) to assess the possible positive impact of malaria drug prophylaxis on cognition; and (iii) to suggest recommendations on minimizing the burden of post-malarial cognitive impairment. METHODS: PUBMED and SCOPUS were searched for all articles with the key word 'Malaria' in the title field and 'cognitive impairment' in any field. Google Scholar was searched for the same keywords anywhere in the article. The search was restricted to articles published in English within the last 15 years (1995-2010). After filtering of abstracts from the initial search, 44 papers had research evidence on this topic. RESULTS & DISCUSSION: Cognitive abilities and school performance were shown to be impaired in sub-groups of patients (with either cerebral malaria or uncomplicated malaria) when compared with healthy controls. Studies comparing cognitive functions before and after treatment for acute malarial illness continued to show significantly impaired school performance and cognitive abilities even after recovery. Malaria prophylaxis was shown to improve cognitive function and school performance in clinical trials when compared to placebo groups. The implications of these findings are discussed.

Success of malaria chemoprophylaxis for outbound civil and military travellers in prevention of reintroduction of malaria in Sri Lanka.

BACKGROUND: Sri Lanka was certified as malaria-free in September 2016. However, the continuous presence of the malaria vector poses serious risks of reintroduction of the disease. Chemoprophylaxis and advice on malaria preventive behaviour for international travellers is a key strategy adopted to reduce the risk of imported malaria. METHODS: We conducted an efficiency study of malaria chemoprophylaxis for civilian and military travellers who requested travel advice from the Anti Malaria Campaign (AMC) prior to departure. The AMC is the only agency that can issue malaria chemoprophylaxis to travellers and hence this sample is representative of all such individuals seeking travel advice in Sri Lanka. RESULTS: A total of 544 (400 civilians and 144 military) travellers were interviewed prior to departure and after return. The majority travelled to African destinations (516/544 [94.8%]) and were prescribed mefloquine (517/544 [95%]). Chemoprophylaxis was well tolerated and discontinuation due to adverse events was minimal. Regular chemoprophylaxis was reported by 505 (92.8%) participants while overseas. The protective efficacy of chemoprophylaxis was 100% among those who complied with the full course. CONCLUSIONS: The compliance with chemoprophylaxis and its protective efficacy were satisfactory in this study. It is an effective tool in preventing imported malaria to post-elimination Sri Lanka.

Clinical features and sociodemographic factors affecting Trichomonas vaginalis infection in women attending a central sexually transmitted diseases clinic in Sri Lanka.

INTRODUCTION: Trichomoniasis is a relatively neglected area of research in Sri Lanka. Given the number of infections observed, an analysis of sociodemographic characteristics of patients would be valuable in prevention. MATERIALS AND METHODS: Data were collected from 359 newly registered women at a tertiary level sexually transmitted diseases clinic over a period of 18 months. Trichomoniasis was diagnosed by culture of vaginal swabs collected from the posterior fornix. RESULTS: The prevalence of trichomoniasis in the sample was 7.2%. Of those who tested positive for trichomoniasis, 76% were in the age group of 21-45 years, 68% were married and living with a spouse and 60% were unemployed. A diagnosis of Trichomoniasis was associated with being married (OR, 1.6; CI, 0.56-4.41), age over 33 years (OR=1.3, CI, 0.55-2.9), being employed (OR, 1.3; CI, 0.56 - 2.94), having an education of less than ten years at school (OR, 3.0; CI 1.28-7.26) and not using condoms during the last sexual act (OR 2.0, CI 0.84-4.86). The risk was less among commercial sex workers (OR, 0.3, CI: 0.14-0.85), those with multiple sexual partners (OR, 0.2; CI; 0.073-0.408) and women reporting extramarital sexual relationships (OR, 0.3; CI, 0.128-0.733). CONCLUSIONS: Education on safe sex and recognition of symptoms is currently targeted at high risk groups such as commercial sex workers. Extending these programmes to the rest of the community will further reduce the risk of transmission of trichomonas.

Improving diagnosis of trichomonas vaginalis infection in resource limited health care settings in sri lanka.

OBJECTIVE: This study was designed to compare diagnosis of trichomoniasis by culture, wet smear examination, and Giemsa stain. A modified technique was used to transport and prepare the specimen to ensure parasite viability prior to Giemsa staining. MATERIALS AND METHODS: A clinic-based prospective study was carried out in association with the National STD/AIDS Control Programme over a period of 18 months. Three swabs were collected from the posterior fornix of 346 newly registered female patients for diagnosis of trichomoniasis. A wet smear was prepared using the first swab. The second swab was placed in 5 mL of 0.9% saline with three drops of 5% glucose at room temperature and centrifuged twice at a low speed prior to preparation of a Giemsa stained smear. The third swab was for culture. The three tests were performed independently. The specificity and sensitivity of the wet smear and Giemsa stain were compared to culture. RESULTS: With culture, the prevalence of trichomoniasis was 6.9% (95% CI: 4.1-9.3%). The Giemsa-stained smear was found to be highly sensitive (100%, 95% CI: 86.2-100%) and specific (99.69%, 95% CI: 98.26-99.95%) compared to culture. The wet smear was less sensitive (95.83%, 95% CI: 79.76-99.26%) but equally specific (100%, 95% CI: 98.82-100%). CONCLUSION: In developing countries, facilities for using culture are limited and wet smear examination in the field is also difficult due to the immediate need for laboratory facilities. Our study demonstrated that, in this setting, using a transport medium prior to Giemsa staining is a feasible alternative, with a high-diagnostic yield.

Malaria is an important differential diagnosis in visitors returning from Sri Lankan National Safari Parks.

Diagnostic confusion may occur between dengue and malaria when febrile patients with thrombocytopenia return from travel to previous malaria endemic areas. Laboratory tests should include blood smear examination for malaria parasites even though current malaria endemicity in Sri Lanka is low.