Conference Papers
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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
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Item Future trends in veterinary public health and emerging viral diseases(Annual Scientific Sessions of the Sri Lanka Veterinary Association., 2012) Sunil-Chandra, N.P.Veterinary Public Health (VPH) is currently defined as "the slim of all contribusions to the physical, melltal and social well-being of humans through an understanding and application of veterinalry science" (WHO 1999). This definition is more consistent with the values. goals and targets of the WHO vision 'Health for all in the 21 st century". Human health is strongly linked to animal health and production. This link between human and animal populations, and with the surrounding environment. is particularly close in developing regions where animals provide transportation. draught power, fuel and clothing as well as proteins (meat, eggs and milk). In both developing and industrialized countries. however, this can lead to a serious risk to public health with severe economic consequences. A number of communicable diseases known as zoonoses are transmitted from animals to humans. Veterinary medicine has a long and distinguished history of contributing to the maintenance and promotion of public health. Approximately 90 percent of the worldwide burden of all causes of death and disability occur in developing regions of the world but only 10 percent of all health care funds are spent in these regions (WIIO & World Bank). Six communicable disease categories that include pneumonia and infiuenza. AIDS. diarrhoeal disease. tuberculosis. malaria and mcasles are responsible for 90 percent of the estimated 13.3 million deaths in children and young aduits worldwide due to major infectious and parasitic diseases. Zoonotic agents contribute in several of these categories. Livestock disease control programmes in developing countries and countries in transition are often established, even though not very critically, on their economic importance. As a result zoonotic control programmes may not be seriously considered, especially if they do not apparently impact animal heahh and produclion. Obviously, there is a need to be¬ter define the economic impact of zoonoses and other veterinary public health problems with ‘burden of disease' analyses, as used by the World Health Organisation (WHO) and the World Bank.Item Enteric pathogens of zoonotic concern in non-human primates in Sri Lanka(European Wildlife Disease Association (EWDA, 2016) Tegner, C.; Sunil-Chandra, N.P.; Ingrid, H.; Perera, V.; Wijesooriya, W.R.P.L.I.; Fahlman, A.Zoonotic disease is a two-way street where humans and other animals are interchanging pathogens. We investigated the occurrence of the potentially zoonotic Campylobacter spp., Salmonella spp. and group A rotaviruses in faecal samples from free-ranging toque macaques and tufted gray langurs in Sri Lanka. Samples were opportunistically collected from primate troops with close human contact at five sites. Standardized culturing was used to detect the bacteria and an ELISA-based dipstick test was used for detection of group A rotaviruses antigens. Genotyping was performed using pulse field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) and the isolates' sensitivity to selected antibiotics was tested with VetMIC TM (National Veterinary Institute, Uppsala, Sweden) panels Camp EU, CLIN GN and GN-mo (version 4). All 98 samples tested negative for rotavirus. The 40 samples from gray langurs were also all negative for Campylobacter spp. and Salmonella spp. Of the 58 samples collected from toque macaques, C. jejuni was isolated from ten, C. coli from four and Salmonella enterica enterica subsp. Virchow from two of the samples. The fact that neither of the bacteria were isolated from tufted gray langur samples could reflect a true difference between the primate species. However, this should be interpreted in the light of a relatively small sample size. Resistance to ampicillin, ciprofloxacin, nalidixic acid and tetracycline was identified in four C. jejuni isolates, of which three were multidrug resistant. In addition, all C. jejuni showed undetectable MIC-values to colistin, while all C. coli were sensitive to the substance. All C. coli were resistant to ampicillin. The S. Virchow isolates were sensitive to all antibiotics tested for. Six strains of C. jejuni were identified using PFGE and MLST clonal complexes were assigned to all isolates. Sequence types were assigned to seven out of ten C. jejuni. The detection of antibiotic resistant zoonotic bacteria in free-ranging toque macaques with close human contact may have implications for both non-human primate conservation and public health in Sri Lanka and beyondItem The use of serology and PCR in the diagnosis of Mycoplasma pneumoniae(Sri Lanka College of Microbiologists, 2010) Wijesooriya, W.R.P.L.I.; Kok, T.W.; Perera, J.; Thilakarathna, Y.; Sunil-Chandra, N.P.INTRODUCTION: M. pneumoniae is the causative agent of primary atypical pneumonia. Patients mount IgM and IgG antibody responses, which are useful diagnostic markers. Tests for specific DNA by polymerase chain reaction (PCR) in respiratory samples offer rapid and highly sensitive detection for M. pneumoniae diagnosis. AIM: To determine the relationship between serology and PCR in the diagnosis of M. pneumoniae inpatients with respiratory tract infections and a control group. METHODOLOGY: Paired sera from 418 adult patients were enrolled (pneumonia - 97, acute bronchitis -183, acute pharyngitis -138). The control group consisted of 87 paired sera from patients without acute respiratory infections. Isotype specific (IgM, IgG) antibodies were tested by M. pneumoniae specific ELISA (IBL-Hamburg-Germany). PCR for M. pneumoniae DNA was done in respiratory samples of serologically positive and age and gender matched serologically negative patients. RESULTS: M. pneumoniae specific IgG was seen in 9.3% (9/97), 5.4% (10/183) and 1.5% (2/138) in patients with pneumonia, acute bronchitis and pharyngitis respectively. IgM was seen in 4.1 % (4/97) and 2.1 % (2/183) and 0% (0/138) respectively. Both IgM and IgG were observed only in patients with pneumonia (2.1% (2/97)). M. pneumoniae DNA was detected in 52% (13/25) of serology confirmed and 15% (4/26) of serology negative cases. CONCLUSION: M. pneumoniae specific DNA was detected in both serologically positive and negative cases. These discordant results showed that with M. pneumoniae infection, both serology and PCR tests should be performed to maximize diagnosis.Item A Study on the appropriateness of current rabies post-exposure therapy in a government hospital of Sri Lanka(Sri Lanka College of Microbiologists, 2002) Dias, K.P.K.; Sunil-Chandra, N.P.OBJECTIVE: To assess the appropriateness of the use of anti-rabies vaccine and immunogfubulin therapy. DESIGN: A hospital based observational descriptive study conducted prospectively. SETTING: Patients receiving post exposure anti-rabies therapy at the Teaching Hospital, Ragama during the month of December 2000 were studied. METHODS: 500 persons seeking RPEP with a history of animal contact were selected by the non-probability sampling method and individually interviewed using a structured questionnaire. The information on the survival or death of the offending animal was obtained during the 14 day observation period. RESULTS: 500 exposed persons included 418 (83.6%), 61 (12.2%),16 (3.2%), 3 (0.6%) and 2 (0.4% ) due to dog, cat, rat, monkey and squirrel contacts respectively. 383 of 500 (77%) had been exposed due to observable animals and in 322 of 383 (84% ), the animal survived beyond the 14 day observation period. In contrast, only in 44 of 383 (11% ), the animal died. In 17of 383 ( 4%) persons exposed to observable animals, the information on death or survival of the animal was not available. The results show that complete RPEP in 61 of 500 (12.2%) cases could have been avoided based on the nature of exposure. In addition, the 4"1 and 5th vaccine doses of 322 of 500 (64.4%) cases too, could have been withheld as the animals responsible for the exposure cases survived beyond the 14 day observation. CONCLUSION: This study clearly shows that use of RPEP is often unnecessary and the expenditure on anti-rabies vaccines and immunoglubilins could have been minimised considerably by greater compliance with the use of proper RPEP guidelines. Education of doctors on logical implementation of RPEP guidelines and the co-operation by the public could optimise the use of this expensive resource in Sri Lanka.Item Prevalence of antibodies to herpes simplex virus types 1 and 2 (hsv-1 and hsv-2) Amongst non-high risk and High risk populations in Sri Lanka(Sri Lanka College of Microbiologists, 2001) Sunil-Chandra, N.P.; Kumarage, J.; Wijesooriya, W.R.P.L.I.; Jayasinghe, S.M.A.S.INTRODUCTION: HSV-1 and HSV-2 infects both the ora cavity and the genital tract whilst the HSV-i generally causes genital infection. Both c these human herpesviruses cause botl primary and recurrent infections leading ft a lifelong persistence of antibodies. Mol infections of either type are asymptomatic Detection of type specific antibodies hai important implications in the diagnosis of HS' infection in sexually active adults ar> prevention of mother to child transmissiof Recently, problems associated with commo epitopes which elicit cross reactiv antibodies in infected individuals have bee overcome by new HSV type specif! serological assays using the gG1 protein < HSV-1 and gG-2 of HSV-2 as antigens. Th study determine the burden and the epidemiology of type specific HSV infection amongst Sri Lankan populations. OBJECTIVE: To estimate and compare age and gender specific seroprevalences of HSV-1 and HSV-2 amongst non-high risk and high risk populations from Sri Lanka. DESIGN: A prospective study among selected target groups. Setting: Children (aged 1-12 years) and non-high risk adults (aged 13-89 years) and blood donors (aged 15-54 years) reported to Teaching Hospital, Ragama, expectant mothers (aged 14-44 years) of Kelaniya Medical Officer of Health (MOH) division, and the patients attended Central STD Clinic Colombo (aged 4-79 years) during the years 2000 and 2001 were included in this study. METHODS: Single sample of blood was obtained from each of 433 children, 757 ante-natal women, 1374 non-high risk adults, 929 blood donors, and 676 STD clinic attendees. Samples were tested for IgG class antibody responses to HSV infections using FDA approved type specific ELISA assay (MRL) at the Dept . of Microbiology, Faculty of Medicine , University of Kelaniya. RESULTS: Overall seroprevalence of HSV-1 among children, ante-natal women, blood donors, adult patients and STD attendees was 51.3%, 75.2%, 79.3%, 75.9% and 78.7% respectively whilst the seroprevalence of HSV-2 was 4.6%, 8.3%, 10.9%, 19.8% and 39.6% respectively. Age and gender specific differences in seroprevalence were observed within study groups.Item The usefulness of rapid screening tests in discriminating normal and infected urine specimens under Sri Lankan conditions(Sri Lanka College of Microbiologists, 2003) Athhukorala, G.I.D.D.A.D.; Nilaweera, T.H.W.T.; Sunil-Chandra, N.P.INTRODUCTION: Tropical climate and improper specimen collection can lead to contamination of urine by the commensal flora and their rapid multiplication prior to the culture. In Sri Lanka, some laboratories use the centrifuged urine for estimating pus cell counts whilst others use the un-centrifuged urine. OBJECTIVE: To assess the usefulness of rapid and simple screening tests for UTI currently available in Sri Lanka STUDY DESIGN: A prospective study over a three months period. SETTINGS: Urine specimens referred to University laboratory from wards of the Teaching Hospital, Ragama. METHODS: Midstream urine specimens from 100 patients presenting with a history of UTI, collected prior to antibiotic therapy were examined within one hour of collection for the determination of urine pus cell and organism counts, nitrate reduction (NR) and leukocyte esterase (LE) activity and the significant bacteriuria. Organism and pus cell counts of un-centrifuged and centrifuged urine using a Neubauer haemocytometer and per high power field (PHF) were examined by microscopy. RESULTS: 28 out of 100 patients enrolled in the study, had significant bacteriuria (>105 colony forming units (CFU) /ml) whilst 17/100 had 'may be significant1 (104'105 CFU/ml) and 55/100 had <104 CFU/ml bacteriuria. The sensitivity and specificity of using the pus cell count /ml of un-centrifuged urine using a Neubauer haemocytometer, compared to the culture positive samples was 71.42%(20/28) and 89.09% (49/55) respectively, at the cut off point of 10s pus cells/ml. The sensitivity and specificity of pus cell count /HPF in un-centrifuged urine was 14.3% (4/28) and 96.4% (53/55) respectively whilst the counts /HPF in centrifuged urine was 57% (16/28) and 91% ( 50/55) respectively. The sensitivity and specificity of the presence of both NR and LE activity in relation to culture was 82.1% and 27.3 % respectively. CONCLUSIONS: The pus cell count/ml of un-centrifuged urine is a better indicator of UTI at the cut off point of 105 pus cells/ml compared to the count per HPF or urine NR and LE activity. Pus cell counts/HPF or organism counts in both un-centrifuged and centrifuged urine were found to have a lower co-relation with the culture positive samples. However, amongst the screening tests assessed, the pus cell count/ml of un-centrifuged urine is superior in terms of sensitivity, specificity and the reliability.Item An epidemiological study on a varicella outbreak among initial entry trainees of the Sri Lankan Army and the cost-effectiveness of vaccinating susceptible individuals(Sri Lanka College of Microbiologists, 2003) Dias, K.P.K.; Sunil-Chandra, N.P.INTRODUCTION: Varicella which is a disease burden to the Sri Lankan Army. VZV immunization of susceptible recruits is limited due to its high cost and therefore, recommendation of vaccination should be evaluated from a cost effectiveness perspective. OBJECTIVE: To study : 1. Spread of a varicella outbreak among initial entry trainees. 2. Usefulness of taking the past history of varicella for screening of susceptible individuals. 3. Cost effectiveness of VZV vaccination of initial entry trainees of the Sri Lankan Army. DESIGN: A hospital based descriptive study conducted prospectively over a period of three months during an outbreak. SETTING: 682 initial entry trainees aged 18-24 years who entered the Volunteer Force Training School of the Sri Lankan Army, Diyatalawa on 21!d July 2002 from various parts of the country were enrolled in this study. They were either hospitalized for varicella at the Army Base Hospital or billeted in the Camp. METHODS: Details of the index, secondary and tertiary cases, and preventive and management measures carried out for varicella patients were recorded. The rate of contracting varicella amongst immune and non-immune recruits based on past history were analyzed. A sample of blood was collected from some patients for the serological confirmation of varicella and rubelSa. Cost effectiveness of VZV vaccination at the Sri Lankan Army Hospital was analyzed. RESULTS: 263 (38.6 %) of all new recruits had a past history of chicken pox and only 9 (3.4%) of them re-infected. A total of 271 recruits were hospitalized for chicken pox during the outbreak and 262 (96.7%) of them did not have a past history. In addition to the varicella, there was also clinical and serological evidence of an outbreak of rubella Vaccination of recruits was found to be cheaper (Rs. 4293.00 or US$ 43.00) compared to the cost of 14 days of hospital stay (Rs. 7265.00 or US$ 72.00). CONCLUSIONS: Hospitalization and treatment of patients with varicella in the Army Hospital found to be more costly compared to the vaccination of susceptible recruits against VZV. Past history of varicella will be useful to identify susceptible new recruits for VZV immunization. Proper isolation of the patients and segregation of susceptible individuals at the index and secondary case levels will minimise the spread.Item Transmission of atypical Myeobacteria by a fiberoptic bronchoscopc leading to a pseudo-outbreak of tuberculosis(Sri Lanka College of Microbiologists, 2003) Somasiri, D.A.D.H.; Wijesinghe, C.K.; Sunil-Chandra, N.P.INTRODUCTION: Failure to eradicate contamination of bronchoscopes that occur during use may lead to person-to-person transmission of Mycobacterium tuberculosis or pseudo-outbreaks from environmental microbes such as nontuberculous mycobacteria. OBJECTIVE: To determine the rate of detection of Mycobacterium strains from sputum and bronchial wash preparations of patients, and the extent of nosocomial transmission of Mycobacterium strains following bronchoscopy, and to determine whether results of smear examination for acid fast bacilli (AFB) can mislead the diagnosis and management of patients. DESIGN ANDSETTING: 107 sputum and 60 broncho alveolar lavage (BAL) samples received from patients suspected of tuberculosis and microbiological specimens from the fiberoptic bronchoscope at the Teaching Hospital, Ragama from January 2001 to October 20027 . METHODS: All samples were stained for AFB with Ziehl-Neelsen stain. Samples which were positive by the stain were inoculated into the Lowenstein-Jensen medium and Para-nitro benzoic acid (PNB) containing medium for culture. RESULTS: 13 of 107 patients' sputum and 39 of 60 patients' BAL samples and the saline wash specimen of the bronchoscope were positive for AFB stain. Sputum of 12/13, BAL samples of 22/39 patients and the saline wash specimen were cultured, 1/12 sputum and 8/22 BAL and the saline wash specimen yielded a growth of an atypical CONCLUSIONS: This study reveals a pseudo-outbreak of acid fast bacilli amongst patients with respiratory disease due to the transmission of non-tuberculous mycobacteria by a fiberoptic bronchoscope indicating the value of positive AFB in BAL for predicting pulmonary tuberculosis is questionable.Item A study on the bio-burden of doctors' and other health care workers' hands, stethoscopes and other medical devices in a Sri Lankan set up - Potential risk of nosocomial infections?(Sri Lanka College of Microbiologists, 2003) Thusharika, M.M.P.; Somasiri, D.A.D.H.; Athukorala, G.I.D.D.A.D.; Sunil-Chandra, N.P.OBJECTIVE: To assess the potential risk of nosocomial infection DESIGN: Descriptive, prospective controlled study over a period of 17 days in November 2002. SETTING: Special care baby unit, labour room, surgical wards 1 and 2. theatre and the intensive care unit of the Teaching Hospital, Ragama. METHODS: Thirty hand imprints including 13 doctors, 17 other health care workers and 85 swabs from 6 stethescopes and 31 medical equipment were taken randomly. Six health care workers and 3 stethoscopes were included for a control study. Cultures were identified and antibiotic sensitivity tests were performed. RESULTS: 97% (29/30) of hand imprints were contaminated. The main pathogen isolated was Staphylococcus aureus (43%). 60% of Staphylococcus aureus strains were methicillin resistant (MRSA) and 33% of MRS A were also resistant to Vancomycin. Vancomycin resistance needs confirmation. There were Klebsiella spp, E. coli and other coliforms in 27%, Pseudomonas spp in 13% and Candida spp in 3%. 73 % (51/85) of equipment were contaminated. There were Staphylococcus aureus in 29%, E. coli, Klebsiella species and other coliforms in 22%, Pseudomonas species in 13%, arid Candida species in 1%. Of the stethescopes. 33% of bells and diaphragms had Staphylococcus aureus. There was complete elimination of organisms from both hands and stethoscopes of the control following the useof4%hibitane CONCLUSION: This study clearly demonstrates the burden of bacterial contamination among hands of healthcare workers in Sri Lanka.Item Evaluation of a rapid whole blood assay for testing dengue patients at point of care(Sri Lanka College of Microbiologists, 2004) Sunil-Chandra, N.P.; Karunasekera, E.W.S.; Somasiri, D.A.D.H.; Samarakoon, S.M.R.M.; Jayawardena, K.A.T.M.; Fernando, W.M.D.; Wijesooriya, W.R.P.L.I.; Garcia, M.INTRODUCTION: Dengue is the most significant mosquito borne viral disease affecting nations from Asia to the Americas. Symptoms associated with dengue infection range in severity. . The presentation of disease is impacted by age, prior exposure to the virus and the infecting strain of virus. The more severe form of the disease (haemorrhagic fever) can lead to mortality are generally associated with Secondary infections. Clinically, the measurement of dengue-specific IgM and elevated IgG, allows for the detection and differentiation of Primary and Secondary dengue infection. This discrimination is particularly important in situations such as outbreaks where the allocation of resources needs to be directed to those at greatest risk. In cities and major regional centers worldwide clinicians have access to traditional serological techniques such as ELISA and HAI that measure IgM and IgG levels. Unfortunately, clinicians in rural and remote areas generally do not have the resources available for this technology. Hence there is high clinical utility in a field diagnostic device which has the ability to rapidly and accurately detect and differentiate dengue infections. OBJECTIVES: To evaluate a novel dengue whole blood assay (PanBio) having the capacity for qualitative detection of both dengue-specific IgM and IgG, and differentiate between primary and secondary dengue with regard to sensitivity and specificity. To meet the demand for testing at the point of care or in the near patient environment, the test was required to have the capacity to detect antibodies in whole blood. DESIGN, SETTING AND METHODS: This assay device was used at the bed site of patients to evaluate its performance. The test is simply performed by adding the specimen to the sample well followed by running buffer to the buffer well, wait 15 minutes and visually reading the results. No additional materials required. 231 hospital inpatients in the Gampaha district of Sri Lanka, using a finger prick drop of blood as the analyte were assessed against PanBio Dengue Capture IgM and IgG ELISA for the period of 6 weeks starting from 10Ih November 2003. The capacity to detect and differentiate presumptive primary and secondary dengue was evaluated. RESULTS: The whole blood dengue cassette was able to detect 151 positive and 80 negative samples where as the ELISA could detect 126 positive samples and 105 negative patients. The detection of IgM and IgG positive samples by the cassette gave a relative sensitivity of 94.5%, specificity of 86% and 87.1% agreement between the assays. The cassette was able to identify 71% of positive samples as primary infections (IgM positive) and 96.7% as secondary infections (IgG positive with or without IgM) compared to ELISA. CONCLUSION: These data indicate that the Whole Blood Dengue Cassette has good utility in the detection of primary and secondary dengue with a very high accuracy in discriminating patients at greatest risk and represents a valuable field based assay to support the clinical evaluation of patients presenting with symptoms suggestive of dengue fever. ACKNOWLEDGEMENTS: PanBio Ltd, Australia for the financial assistance and Directors of Teaching hospital Ragama and Base hospitals of Negombo, Gampaha and Wathupitiwala.