Evaluation of surveillance case definition in the diagnosis of leptospirosis, using the Microscopic Agglutination Test: a validation study

Background  

Leptospirosis is endemic in both urban and rural areas of Sri Lanka and there had been many out breaks in the recent past. This study was aimed at validating the leptospirosis surveillance case definition, using the Microscopic Agglutination Test (MAT).     

Incidence and effects of Varicella Zoster Virus infection on academic activities of medical undergraduates - a five-year follow-up study from Sri Lanka

Background  

The adult population in Sri Lanka is having high level of susceptibility for Varicella Zoster Virus (VZV) infection. Among medical undergraduates, 47% are VZV seronegative. The purpose of the present study was to determine the incidence of VZV infection in medical undergraduates in Sri Lanka, and to describe the effects of VZV infection on their academic activities.     

Manifestations and outcomes of leptospirosis during local outbreaks in high endemic districts of Sri Lanka: A retrospective multi-center study

Objective: To determine the clinical presentations and disease outcomes of suspected and confirmed cases of leptospirosis from 3 high endemic districts of Sri Lanka, during outbreaks reported between 2013 and 2017. Methods: The retrospective multi-center study was carried out during 2013-2017 in 5 selected hospitals representing 3 high endemic districts in Sri Lanka. Clinically suspected leptospirosis patients were recruited according to the Communicable Disease Epidemiology Profile Sri Lanka, WHO. Leptospirosis was confirmed by either single microscopic agglutination test titre 1: 400 or by positive polymerase chain reaction(PCR) test result. Results: Out of 372 clinically suspected cases, 29.00% were confirmed as leptospirosis cases by either microscopic agglutination test(50.00%) or positive polymerase chain reaction(52.77%) and 12.90% were presumptively identified as leptospirosis. Clinical symptoms(headache, vomiting, jaundice and dyspnoea) and variations in haematological parameters(haemoglobin, platelet count) and biochemical parameters(serum creatinine, serum urea, serum bilirubin and C-reactive protein) were associated with confirmed leptospirosis(P0.05). Acute kidney injury, meningitis, myocarditis, pulmonary haemorrhage and acute liver failure was seen among 21.30%, 12.04%, 6.48%, 6.48%, 5.56%, respectively with 4.63% fatality among the leptospirosis confirmed patients. The sensitivity, specificity, positive predictive value and negative predictive value of the case definition of Ministry of Health, Sri Lanka were 96.29%, 9.09%, 31.13%and 85.71%, respectively, when benchmarked against either positive polymerase chain reaction or microscopic agglutination test as the gold standard. Conclusions: Acute kidney injury is the predominant complication observed among the leptospirosis confirmed patients. However, pulmonary haemorrhage is predominantly associated with mortality. The case definition of Ministry of Health, Sri Lanka is found to have higher sensitivity and enabled the screening of all probable cases of leptospirosis.     

Synchronous liver metastasis in colorectal cancer in Sri Lanka

Objective  

To assess the incidence of synchronous colorectal liver metastasis in patients referred to a tertiary referral center in Sri Lanka and to evaluate the differences in the clinicopathological features of patients with and without synchronous metastasis.     

The influenza pandemic of 1918–1919 in Sri Lanka: its demographic cost,timing, and propagation

Background

As an island and a former British colony, Sri Lanka is a case of special interest for the study of 1918–1919 influenza pandemic because of its potential for isolation from as well as integration into the world epidemiologic system.

Objectives

To estimate population loss attributable to the influenza pandemic and weekly district-level excess mortality from the pandemic to analyze its spread across the island.

Methods

To measure population loss, we estimated a population growth model using a panel of 100 district-level observations on population for five consecutive censuses from 1891 to 1931, allowing for a one-time drop in population in 1918–1919. To estimate weekly excess mortality from the pandemic, we estimated a seasonally adjusted weekly time series of district-specific mortality estimates from vital registration records, ranked them, and plotted the ranks on weekly maps to create a picture of the geographic pattern of propagation across Sri Lanka.

Results

Total loss of population from the influenza pandemic was 307 000 or approximately 6·7% of the population. The pandemic peaked in two discrete (northern and southern) regions in early October of 1918 and in a third (central) region in early March 1919.

Conclusions

The population loss estimate is significantly higher than earlier estimates of mortality from the pandemic in Sri Lanka, suggesting underreporting of influenza-attributable deaths and a role for influenza-related fertility declines. The spatial pattern of peak mortality indicates the presence of two distinct entry points and three distinct epidemiologic regions, defined by population density and ethnicity, in colonial Sri Lanka.     

Prevalence and carrier status of leptospirosis in smallholder dairy cattle and peridomestic rodents in Kandy, Sri Lanka

Leptospirosis is an important bacterial zoonotic disease globally and one of the notifiable diseases in Sri Lanka. Other than human leptospirosis, little information is available on leptospirosis in domestic and feral animals in Sri Lanka. Thus, this study attempted to determine the prevalence and carrier status of leptospirosis in smallholder dairy cattle and peridomestic rodents to understand the impact of the disease on public health in Kandy, Sri Lanka. Cattle and rodent samples were collected from the Yatinuwara and Udunuwara divisional secretaries in Kandy. Serum samples were analyzed for the presence of antileptospiral antibodies using microscopic agglutination test. DNA was extracted from cattle urine and rodent kidney tissue samples, in which polymerase chain reaction was carried out to detect the Leptospira flaB gene. The cattle in 19 (38.8%) of the 49 farms harbored antileptospiral antibodies. Out of 113 cattle serum samples, 23 (20.3%) were positive; 17 (73.9%) and 6 (26.1%) reacted with serogroups Sejroe and Hebdomadis, respectively. Out of the 74 rodent samples, 13 (17.5%) were positive; 8 (61.5%) and 4 (30.8%) had reactions to serogroups Javanica and Icterohaemorrhagiae, respectively. Leptospiral DNA was detected in one cattle urine sample and identified as Leptospira interrogans. This study revealed a high prevalence of leptospirosis in cattle and rodents in Kandy. These animals were infected with a wide array of leptospiral serogroups, which are consistent with the research findings observed in humans in Kandy. Overall, serological data indicate that relative to rodents, cattle may be a more significant reservoir for human transmission and a greater source of potential risk to local agricultural communities.     

Serological evidence of Thailand virus-related hantavirus infection among suspected leptospirosis patients in Kandy, Sri Lanka

A cross-sectional study was undertaken to determine the current prevalence of leptospirosis and hantaviral infections, and the socio-demographic characteristics and risk factors of infected patients, in Kandy, Sri Lanka. This report discusses the serological evidence of hantavirus infections among 105 suspected leptospirosis patients, 8 of whom had hantavirus antibodies. Serotyping ELISA showed that these 8 patients had high optical density values for Thailand virus. Most of the sera showed that the focus reduction neutralization test titer against Thailand virus was higher than that against Seoul virus, thereby suggesting that the hantaviral antibodies found in Sri Lanka are different from Seoul virus but closely related to Thailand virus. These findings imply that the hantaviral infection found in Kandy, Sri Lanka appears to be due to a virus similar to Thailand virus. Epidemiological analysis revealed that the association between hantavirus infection and socio-demographic characteristics was not statistically significant.     

The burden of diabetes mellitus and impaired fasting glucose in an urban population of Sri Lanka

Aims

To describe the burden of diabetes mellitus and impaired fasting glucose in middle‐aged residents (35–64 years) in an urban area of Sri Lanka.

Methods

A cross‐sectional survey was conducted in the Ragama Medical Officer of Health area, from which 2986 participants (1349 men and 1637 women) were randomly selected from the electoral registry between January and December 2007. The participants underwent a physical examination and had their height, weight, waist and hip circumferences and blood pressure measured by trained personnel. Fasting blood samples were taken for measurement of glucose, HbA_1c and lipids. The prevalence of diabetes (fasting plasma glucose > 7 mmol/l) and impaired fasting glycaemia (fasting plasma glucose 5.6–6.9 mmol/l) and major predictors of diabetes in Sri Lanka were estimated from the population‐based data.

Results

Age‐adjusted prevalence of diabetes mellitus in this urban population was 20.3% in men and 19.8% in women. Through the present screening, 263 patients with diabetes and 1262 with impaired fasting glucose levels were identified. The prevalence of newly detected diabetes was 35.7% of all patients with diabetes. Among patients with diabetes, only 23.8% were optimally controlled. In the regression models, high BMI, high waist circumference, high blood pressure and hypercholesterolaemia increased the fasting plasma glucose concentration, independent of age, sex and a family history of diabetes.

Conclusions

Our data demonstrate the heavy burden of diabetes in this urban population. Short‐ and long‐term control strategies are required, not only for optimal therapy among those affected, but also for nationwide primary prevention of diabetes.     

Thrombocytopenia in the experimental leptospirosis of guinea pig is not related to disseminated intravascular coagulation

Background  

Thrombocytopenia is commonly observed in severe leptospirosis. However, previous studies on coagulation alterations during leptospirosis resulted in inconsistent conclusions. Some findings showed that the prominent levels of thrombocytopenia observed in severe leptospirosis did not reflect the occurrence of disseminated intravascular coagulation (DIC) syndrome, while the others reached the conclusion that the hemorrhages observed in leptospirosis were due to DIC. The aim of this study is to elucidate whether DIC is an important feature of leptospirosis.     

Necrotizing fasciitis involving the chest and abdominal wall caused by Raoultella planticola

Background

Dengue is considered one of the most common mosquito borne illnesses in the world. Although its clinical course is usually uneventful, complications have rarely been known to arise. These include neurological manifestations such as neuropathies.

Case presentation

We report a middle aged patient from urban Sri Lanka who developed diaphragmatic paralysis secondary to phrenic neuropathy a month after recovering from dengue fever. He was managed conservatively and made a full recovery subsequently.

Conclusion

Isolated phrenic nerve palsy causing diaphragmatic paralysis should be considered a recognized complication of Dengue fever. A patient usually gains full recovery with conservative management.     

Glucose-lowering drug use in migrants and native Danes with type 2 diabetes: Disparities in combination therapy and drug types

Aim

To examine disparities in glucose-lowering drug (GLD) usage between migrants and native Danes with type 2 diabetes (T2D).

Materials and Methods

In a nationwide, register-based cross-sectional study of 253 364 individuals with prevalent T2D on December 31, 2018, we examined user prevalence during 2019 of (i) GLD combination therapies and (ii) individual GLD types. Migrants were grouped by origin (Middle East, Europe, Turkey, Former Yugoslavia, Pakistan, Sri Lanka, Somalia, Vietnam), and relative risk (RR) versus native Danes was computed using robust Poisson regression to adjust for clinical and socioeconomic characteristics.

Results

In 2019, 34.7% of native Danes received combination therapy, and prevalence was lower in most migrant groups (RR from 0.78, 95% confidence interval CI 0.71-0.85 [Somalia group] to 1.00, 95% CI 0.97-1.04 [former Yugoslavia group]). Among native Danes, the most widely used oral GLD was metformin (used by 62.1%), followed by dipeptidyl peptidase-4 inhibitors (13.3%), sodium-glucose cotransporter-2 inhibitors (11.9%) and sulphonylureas (5.2%), and user prevalence was higher in most migrant groups (RR for use of any oral GLD: 0.99, 95% CI 0.97-1.01 [Europe group] to 1.09, 95% CI 1.06-1.11 [Sri Lanka group]). Furthermore, 18.7% of native Danes used insulins and 13.3% used glucagon-like peptide-1 receptor agonists (GLP-1RAs), but use was less prevalent in migrants (RR for insulins: 0.66, 95% CI 0.62-0.71 [Sri Lanka group] to 0.94, 95% CI 0.89-0.99 [Europe group]; RR for GLP-1RAs: 0.29, 95% CI 0.22-0.39 [Somalia group] to 0.95, 95% CI 0.89-1.01 [Europe group]).

Conclusions

Disparities in GLD types and combination therapy were evident between migrants and native Danes. Migrants were more likely to use oral GLDs and less likely to use injection-based GLDs, particularly GLP-1RAs, which may contribute to complication risk and mortality among this group.     

Characteristics of Rural Leptospirosis Patients Admitted to Referral Hospitals during the 2008 Leptospirosis Outbreak in Sri Lanka: Implications for Developing Public Health Control Measures

To determine the exposure risk factors of highly endemic rural leptospirosis in tropical setting, we conducted a prospective, hospital-based case control study in Sri Lanka. A conceptual hierarchy of variables was used to analyze the data. Case patients included 38 (34%) females and 73 (66%) males with a mean age of 36 yr (SD 12.7 yr). Using piped, chlorinated water for drinking/general purposes (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.16–0.67), paddy fields in the vicinity of home (OR 1.77, 95% CI 1.06–2.97), sighting dogs at home yard/dog ownership (OR 1.79, 95% CI 1.11–2.91), sighting cattle at home yard/cattle ownership (OR 1.69, 95% CI 1.00–2.84), and work in a paddy field (OR 3.02, 95% CI 1.68, 5.41) were the main predictors of leptospirosis among febrile patients. In high endemic tropical settings with rural leptospirosis, risk factors in residential environments, rather than individual exposures, seemed to play a major role in leptospirosis disease transmission.     

A quantitative PCR (TaqMan) assay for pathogenic Leptospira spp

Background  

Leptospirosis is an emerging infectious disease. The differential diagnosis of leptospirosis is difficult due to the varied and often "flu like" symptoms which may result in a missed or delayed diagnosis. There are over 230 known serovars in the genus Leptospira. Confirmatory serological diagnosis of leptospirosis is usually made using the microscopic agglutination test (MAT) which relies on the use of live cultures as the source of antigen, often performed using a panel of antigens representative of local serovars. Other techniques, such as the enzyme linked immunosorbent assay (ELISA) and slide agglutination test (SAT), can detect different classes of antibody but may be subject to false positive reactions and require confirmation of these results by the MAT.     

Clinical manifestations of dengue and leptospirosis in children in Mumbai: an observational study

Objectives  

The aim of this study was to determine the causes of acute febrile illness in children presenting to our hospital following an extremely heavy rainfall event in the city of Mumbai in 2005. The clinical and laboratory manifestations of leptospirosis and dengue together with their outcomes are also described.     

Clinical features of chikungunya infection in Sri Lanka

Objective

To investigate the clinical features of chikungunya fever (CHIKF) outbreak in Sri Lanka in 2006 and to estimate the relative risk for CHIKF for various demographic factors.

Methods

A total of 885 individuals belonging to 200 families were studied individually for surveillance of this disease, symptoms, contraction order within the family and means of treatments. Relative risks for CHIKF for demographic characters such as gender, age and educational levels were estimated. The associations of symptoms with age and gender were also studied.

Results

The estimated surveillance of CHIKF in the studied population was 89.2%. The duration of suffering due to this disease was 50.9 d (95% CI, 47.3, 53.9 d) with fever for 3.9 d (95% CI, 3.7, 4.1 d). 93% of the CHIKF patients felt at least one type of joint pain and 8% felt joint swellings. Rash was observed in 15.1% of the patients. Buccal bleeding and mouth ulcer were observed in 1.5% and 9.3% respectively. About 22.7% of the CHIKF patients had vomiting. Female had 1.48 folder higher relative risk for CHIKF infection. The duration suffered due to CHIKF, duration of fever and contraction order within family were highly associated with age (P<0.000). Female patients had more than one folder higher relative risks for the symptoms such as rash, vomiting, buccal bleeding and mouth ulcer (P<0.000).

Conclusions

The surveillance of CHIKF in Sri Lanka was a severe outbreak which infected much on female and caused more suffering on aged population. The symptoms such as rash, bleeding from mucosa, mouth ulcer and vomiting were highly associated with gender. The reasons for these observations need to be further explored.     

Sri Lankan National Melioidosis Surveillance Program Uncovers a Nationwide Distribution of Invasive Melioidosis

The epidemiologic status of melioidosis in Sri Lanka was unclear from the few previous case reports. We established laboratory support for a case definition and started a nationwide case-finding study. Suspected Burkholderia pseudomallei isolates were collated, identified by polymerase chain reaction assay, referred for Matrix Assisted Laser Desorption Ionization-Time of Flight analysis and multilocus sequence typing (MLST), and named according to the international MLST database. Between 2006 and early 2014, there were 32 patients with culture-confirmed melioidosis with an increasing annual total and a falling fatality rate. Patients were predominantly from rural communities, diabetic, and male. The major clinical presentations were sepsis, pneumonia, soft tissue and joint infections, and other focal infection. Burkholderia pseudomallei isolates came from all parts of Sri Lanka except the Sabaragamuwa Province, the south central hill country, and parts of northern Sri Lanka. Bacterial isolates belonged to 18 multilocus sequence types, one of which (ST 1137) was associated with septicemia and a single-organ focus (Fisher''s exact, P = 0.004). Melioidosis is an established endemic infection throughout Sri Lanka, and is caused by multiple genotypes of B. pseudomallei, which form a distinct geographic group based upon related sequence types (BURST) cluster at the junction of the southeast Asian and Australasian clades.     

Phylogeography and Molecular Epidemiology of an Epidemic Strain of Dengue Virus Type 1 in Sri Lanka

In 2009, a severe epidemic of dengue disease occurred in Sri Lanka, with higher mortality and morbidity than any previously recorded epidemic in the country. It corresponded to a shift to dengue virus 1 as the major disease-causing serotype in Sri Lanka. Dengue disease reached epidemic levels in the next 3 years. We report phylogenetic evidence that the 2009 epidemic DENV-1 strain continued to circulate within the population and caused severe disease in the epidemic of 2012. Bayesian phylogeographic analyses suggest that the 2009 Sri Lankan epidemic DENV-1 strain may have traveled directly or indirectly from Thailand through China to Sri Lanka, and after spreading within the Sri Lankan population, it traveled to Pakistan and Singapore. Our findings delineate the dissemination route of a virulent DENV-1 strain in Asia. Understanding such routes will be of particular importance to global control efforts.