Vasanthi Thevanesam

Leptospirosis Outbreak in Sri Lanka in 2008: Lessons for Assessing the Global Burden of Disease

Global leptospirosis disease burden estimates are hampered by the lack of scientifically sound data from countries with probable high endemicity and limited diagnostic capacities. We describe the seroepidemiologic and clinical characteristics of the leptospirosis outbreak in 2008 in Sri Lanka. Definitive/presumptive case definitions proposed by the World Health Organization Leptospirosis Epidemiology Reference Group were used for case confirmation. Of the 404 possible cases, 155 were confirmed to have leptospirosis. Highest titers of patient seum samples reacted with serovars Pyrogenes (28.7%), Hardjo (18.8%), Javanica (11.5%), and Hebdomadis (11.5%). Sequencing of the 16S ribosomal DNA gene identified six infections: five with Leptospira interrogans and one with L. weilli. In this patient population, acute renal failure was the main complication (14.8%), followed by myocarditis (7.1%) and heart failure (3.9%). The case-fatality rate was 1.3%. This report strengthens the urgent need for increasing laboratory diagnostic capabilities to determine the causes of epidemic and endemic infectious diseases in Sri Lanka, a finding relevant to other tropical regions.

Antibacterial activity of xanthones from Garcinia mangostana (L.) and their structure–activity relationship studies

Antibacterial activities of prenylated xanthones from Garcinia mangostana and their synthetic analogues were investigated, and their structure–activity relationships have been studied. γ-Mangostin has shown antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-sensitive Enterococcus (VSE) strains at MICs 3.13, 6.25, 6.25 and 6.25 µg mL−1, respectively. In these experiments, gentamicin was used as the positive control. Further, some analogues of γ-mangostin and α-mangostin were synthesised and their activity was tested against MRSA and VRE strains. The analysis of the bioassay results above indicated that, the combination of C-6 and C-3 hydroxyl groups along with the prenyl side chain at C-2 in the 1,3,6,7-tetraoxygenated xanthones from G. mangostana is essential to have a high antibacterial activity.

Detection of Rickettsioses and Q fever in Sri Lanka

Current serological evidence suggests the presence of scrub typhus and spotted fever group (SFG) rickettsiosis in Sri Lanka. Our objective was to identify rickettsial agents/Q fever as aetiological causes for patients who were presumed having rickettsioses by the presence of an eschar or a rash. Sera from patients with unknown origin fever from Matara were tested by immunofluorescence for SFG rickettsial antigens, typhus group rickettsiae, Orientia tsutsugamushi, and Coxiella burnetii antigens. Thirteen (7.3%) of the patients presented with a rash, 11 (6.1%) had an inoculation eschar, and 16 patients recalled a tick or flea bite. We found that 25 (14%) patients had scrub typhus, 6 (3%) SFG rickettsioses, 3 (1.6%) acute Q fever, 3 (1.6%) murine typhus, and 3 (1.6%) were infected by Rickettsia felis. In addition to already described scrub and murine typhus, we found that R. felis and C. burnetii infections should be considered in Sri Lanka.

Seroepidemiololgy of rickettsioses in Sri Lanka: a patient based study

BackgroundRickettsioses are emerging infections in Sri Lanka as shown by the increase in the number of clinically diagnosed rickettsial patients being reported to the Epidemiology Unit, Sri Lanka. However, mapping the disease for the whole island with laboratory confirmed cases has not been previously carried out.Methods615 samples received from 23 hospital representing 8 provinces were tested using ELISA or IFA methods and clinical data was collected using a validated questionnaire.ResultsRash was found among more spotted fever seropositive patients than scrub typhus seropositive patients while the opposite was true for the presence of eschar. Spotted fever and scrub typhus was found in a geographically restricted manner. Consistent temporal patterns were seen for the presentation of patients with rickettsioses in Kandy and Kurunegala districts for 2009 and 2010.ConclusionsThis study expanded knowledge on the distribution of rickettsioses in Sri Lanka and their clinical profiles which in turn helps in the clinical diagnosis of these infections.

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 (Fishers 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.

Molecular characterization of Mycobacterium tuberculosis isolates from Kandy, Sri Lanka

Abstract Objective To determine tuberculosis epidemiology in Kandy, Sri Lanka. Methods IS 6110 RFLP and spoligotyping analyses were performed on 100 Mycobacterium tuberculosis ( M. tuberculosis ) clinical isolates from Kandy district, Sri Lanka. RFLP hybridization patterns ( n =73) were analysed by the software GeneDirectory. Spoligotypes ( n =110) were compared with the international database SPOTCLUST. Results The majority of the circulating M. tuberculosis strains in Kandy belong to a single family, but the degree of IS 6110 DNA polymorphism was high. 71 (80%) of the strains displayed distinct RFLP patterns and 63 (71%) were clustered into one main family. Within the family three isolates were grouped into one cluster while the rest isolates were grouped into one. The copy number varied from 1 to 17 while single copy strains were predominant (12) and 15 lacked the IS 6110 element. Spoligotyping revealed a total of 24 families including the 9 major families. Strains were distributed among all the three principle genetic groups PGG1, PGG2, and PGG3. Except for two strains, the rest were not defined in the latest spoligotype database SpolDB4/SITVIT. Conclusions The first study of RFLP and spoligotyping of M. tuberculosis strains in Sri Lanka demonstrates the applicability of the genetic marker IS 6110 to differentiate strains and the heterogeneity and predominance of several worldwide-distributed spoligotypes.

Determinants of leptospirosis in Sri Lanka: Study Protocol

BackgroundLeptospirosis is becoming a major public health threat in Sri Lanka as well as in other countries. We designed a case control study to determine the factors associated with local transmission of leptospirosis in Sri Lanka, in order to identify major modifiable determinants of leptospirosis. The purpose of this paper is to describe the study protocol in detail prior to the publishing of the study results, so that the readership will be able to understand and interpret the study results effectively.MethodsA hospital based partially matched case control design is proposed. The study will be conducted in three selected leptospirosis endemic districts in central Sri Lanka. Case selection will include screening all acute fever patients admitted to selected wards to select probable cases of leptospirosis and case confirmation using an array of standard laboratory criteria. Age and sex matched group of acute fever patients with other confirmed diagnosis will be used as controls. Case to control ratio will be 1:2. A minimum sample of 144 cases is required to detect 20% exposure with 95% two sided confidence level and 80% power. A pre tested interviewer administered structured questionnaire will be used to collect data from participants. Variables included in the proposed study will be evaluated using conceptual hierarch of variables in three levels; Exposure variables as proximal; reservoir and environmental variables as intermediate; socio-demographic variables as distal. This conceptual hierarch hypothesised that the distal and intermediate variables are mediated through the proximal variables but not directly. A logistic regression model will be used to analyse the probable determinants of leptospirosis. This model will evaluate the effect of same level and upper level variables on the outcome leptospirosis, using three blocks.DiscussionThe present national control programme of leptospirosis is hampered by lack of baseline data on leptospirosis disease transmission. The present study will be able to provide these essential information for formulation of better control strategies.

Deployable Laboratory Response to Emergence of Melioidosis in Central Sri Lanka

ABSTRACT A portable molecular diagnostic laboratory was used to provide molecular confirmation of suspected melioidosis cases seen at Peradeniya Hospital, central Sri Lanka. Soil supernatants from rice field and rubber plantation samples also produced PCR-positive results. These procedures could be used for melioidosis field work in other remote locations.

Methicillin resistant Staphylococcus aureus: the scale of the problem in a Shri Lankan hospital

A three month surveillance study of methicillin resistant Staphylococcus aureus (MRSA) was carried out in the male surgical unit of the General Hospital, Peradeniya, Shri Lanka. Nose, throat, axillary, perineal and wound swabs were taken from 251 patients and 35 staff members. Eighty-four (27.5%) of 305 isolates of S. aureus from patients were MRSA. Seventy-three of these isolates were also resistant to penicillin, tetracycline, erythromycin, gentamicin, chloramphenicol and co-trimoxazole. All isolates were sensitive to fusidic acid, clindamycin, vancomycin and rifampicin. The acquisition of MRSA was higher than of methicillin sensitive S. aureus (MRSA). No deaths occurred due to MRSA. Staff carriage was only 6%. The treatment and management of MRSA in hospitals with very poor resources requires further study of interventions which are practicable in this situation.

Acute meningoencephalitis associated with echovirus 9 infection in Sri Lanka, 2009

The aetiology of acute meningoencephalitis in Sri Lankan children and adults is poorly understood. This study was carried out to determine pathogens responsible for meningoencephalitis in Sri Lanka. A hospital‐based cross‐sectional study was performed using cerebrospinal fluid samples (22 adult and 17 pediatric) collected from August to December 2009 from patients clinically diagnosed with acute meningoencephalitis at two tertiary care hospitals in Sri Lanka. Routine microbiology for bacterial pathogens together with in‐house RT‐PCR and PCR assays for the detection of dengue viruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, enteroviruses, mumps virus, measles virus, herpes simplex viruses types 1 and 2, and varicella zoster virus were performed. Bacterial pathogens were not isolated from any patient specimens. However, from nine of the paediatric patients aged 1 month to 10 years (mean age 5.2 years) echovirus 9 (E‐9; family Picornaviridae, genus Enterovirus,species Enterovirus B ) was detected by RT‐PCR. All nine patients presented with fever, six had headache, and seven had vomiting. Neck stiffness indicating meningitis was present in six of the patients. Phylogenetic analysis of partial VP1 and VP4‐VP2 genes showed these E‐9 strains to be most closely related to E‐9 strains detected in CSF from Korea and France in 2005 and 2006. The remaining patients were negative for all other viruses tested. E‐9 was the most common cause of acute meningoencephalitis in the tested paediatric population from Sri Lanka in 2009, which likely reflects circulation of this E‐9 strain between Europe and Asia over several years. J. Med. Virol. 87:2033–2039, 2015.