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Biomedical subjects

A R Wickremasinghe

Publications and source records attributed to A R Wickremasinghe.

At least 19 recordsLinked to original sources
PubMed2006

Anopheline breeding in river bed pools below major dams in Sri Lanka.

Anopheline mosquito larval surveys were carried out from September 2000 to August 2002 in Mahaweli and Kelani river beds, below five major dams in the wet and intermediate zones of Sri Lanka, to study the prevalence of anopheline species in these areas. In each study site, all permanent and semi-permanent pools were surveyed fortnightly by dipping at 6 dips/m(2) surface area of water. Larvae were collected in separate containers, staged and identified at their third and fourth stages. During each survey, the surface area and depth of pools were recorded and each reading was considered as an individual observation. River bed pools below the dams contained stagnant clean water with a little or no aquatic vegetation. The majority of pools were < or =1m(2) in surface area and < or =75 cm in depth. Anopheline mosquito breeding was seen throughout the year in each study site. The average percentage of pools positive for anopheline larvae, the number of larvae per 100 pools and 100 dips were 14.85%, 32.34 and 9.29, respectively. Thirteen anopheline species, including 10 potential vectors, namely, An. barbirostris, An. culicifacies, An. jamesii, An. maculatus, An. nigerrimus, An. peditaeniatus, An. subpictus, An. tessellatus, An. vagus and An. varuna were found breeding in the river bed pools.

Animals↗
PubMed2006

Toxicity due to organophosphorus compounds: what about chronic exposure?

The inappropriate use of toxic chemicals is common in developing countries, where it leads to excessive exposure and high risks of unintentional poisoning. The risks are particularly high with the pesticides used in agriculture, where poor rural populations live and work in close proximity to these compounds, which are often stored in and around the home. It is estimated that 99% of all deaths from pesticide poisoning occur in developing countries. Whilst the acute toxicity of pesticides has been well documented, there is still relatively little known of the effects on health of chronic pesticide exposure. Organophosphate insecticides have been extensively used in agriculture in developing countries, with little protection for the communities and individuals thus exposed. Given the indisputable chronic exposure of vulnerable groups to organophosphate compounds, including pregnant women, the fetus and young children, the potential for widespread adverse effects is considerable. Thus, whilst there is some evidence that chronic exposure may have adverse effects on health, there is an urgent need for high-quality observational and interventional studies of both occupational and environmental exposure to these compounds.

Animals↗
PubMed2006

Larvivorous potential of fish species found in river bed pools below the major dams in Sri Lanka.

Malaria in Sri Lanka is closely associated with the river systems in the country. Construction of major dams across rivers has resulted in year-round pooling and anopheline mosquito breeding in river beds below the dams. This study was carried out to determine the larvivorous activity of fish found in river bed pools below the dams to identify the potential fish species for anopheline larval control in these areas. Fish species in five river beds below the dams, namely, Laxapana, Kotmale, Nilambe, Victoria, and Rantembe, were identified in June 2000. The larvivorous potential of the 12 fish species collected was determined in the laboratory based on the number of larvae consumed per fish within 10 min and an hour. Danio malabaricus Jerdon, Oreochromis mossambicus Peters, Oreochromis niloticus L., and Poecilia reticulata Peters consumed nine or more larvae per fish within 10 min. Aplocheilus dayi Steindachner and Rasbora daniconius Hamilton consumed nine and eight larvae, respectively, within 1 h. O. mossambicus, O. niloticus, and P. reticulata consumed 10 larvae per fish within 10 min. Despite some species having a high larvivorous potential in the laboratory, field studies are required to determine the feasibility of using these fish for anopheline mosquito control in the river bed pools below the dams.

Animals↗
PubMed2006

Anti-tuberculosis drug inducd hepatitis - a Sri Lankan experience.

OBJECTIVE: To assess the incidence of anti-tuberculosis (TB) drug induced hepatitis (AIH) in Sri Lankan patients, determine risk factors of AIH, and to address management options in AIH. DESIGN: A prospective study. SETTING: Chest Hospital, Welisara, Sri Lanka, from April 2001 to April 2002. PATIENTS: Seven hundred and eighty three patients with a confirmed diagnosis of TB and resident in the Colombo and Gampaha districts who presented to Chest Hospital, Welisara, Sri Lanka. METHODS: WHO recommended treatment was commenced in all cases. AIH was diagnosed when patients complained of decreased appetite with nausea or vomiting and elevated serum bilirubin (SB; >1.1 mg/dL) or elevated serum alanine transferase (ALT; > 3 times upper limit of normal). RESULTS: Of 783 enrolled patients, 74 (9.5%) developed AIH, the majority (58%) developing AIH within the first 2 weeks of the intensive phase of treatment. AIH was more common among patients over 60 years (p = 0.018), who developed pulmonary TB (p = 0.028), and in patients weighing 33-55 kg (p = 0.004). Age, weight and rifampicin overdosage were significant predictors of AIH. Of the 74 AIH patients, standard treatment was restarted in 60, treatment modified in six, two defaulted and six died. CONCLUSIONS: The incidence of AIH in Sri Lanka is 9.5% in treated patients. AIH was associated with age, low body weight and rifampicin overdosage.

Adolescent↗
PubMed2005

Malarial vectors in an irrigated rice cultivation area in southern Sri Lanka.

Entomological surveys were carried out from March 1998 to December 1999 to study the prevalence, distribution and abundance of malarial vectors in relation to selected environmental factors and potential mosquito breeding sites in irrigation channels in 15 villages in the Lunugamvehera Irrigation and Settlement Project, a malaria-endemic area of southern Sri Lanka. Mosquito collections were made at monthly intervals using four sampling methods. Thirteen anopheline species were collected. Following monsoonal rains, anopheline breeding took place primarily in rainwater accumulations. During the inter-monsoonal period, pools formed in the irrigation system, semi-permanent pools formed as a result of rainfall and permanent ground pools were the major breeding sites of anophelines. Very little anopheline breeding took place within the irrigation channels. Amongst the seven anopheline species collected from human dwellings, Anopheles subpictus was the most prevalent, followed by A. culicifacies; together these two species comprised more than 99% of the indoor resting population. The number of days of rain was an important macro-epidemiological factor influencing the density of malarial vectors. There was no consistent trend between the amount of water released or the number of days of water release from the reservoir and the outdoor or indoor resting densities of anophelines.

Agriculture↗
PubMed2005

ABO-blood-group types and protection against severe, Plasmodium falciparum malaria.

Although the ABO blood group of the human host has been reported to influence malarial infection, there have been few clinical observations on this effect. A hospital-based, comparative study was therefore performed to investigate the relationship between blood-group type and severe disease i nPlasmodium falciparum malaria. Overall, 243 cases of malaria (163 uncomplicated and 80 severe) and 65 patients with severe, non-malarial infections were studied. In terms of ABO-blood-group composition, the patients with severe malaria were significantly different from the patients with the uncomplicated disease (P<0.001) and also from a population control described previously (P<0.0001). The patients with uncomplicated malaria or severe but non-malarial disease were, however, similar to the population control. The cases of severe malaria were significantly less likely to be of blood group O (P=0.0003), and significantly more likely to be of group AB (P<0.0001), than the patients with nonsevere malaria. It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection.

ABO Blood-Group System↗
PubMed2005

Hospitalisation trends due to selected non-communicable diseases in Sri Lanka, 2005-2010.

OBJECTIVES: To project hospitalisation trends due to selected non-communicable diseases (NCD) from 2005 to 2010. DESIGN: Morbidity data, maintained at the Medical Statistics Unit of the Ministry of Health, from 1981 to 2000, were used to model trends of hospitalisation due to diabetes mellitus, hypertensive disease and ischaemic heart disease. Linear and quadratic trends were used to model morbidity trends. RESULTS: For all three diseases considered, the increase in the incidence of hospitalisation is exponential. An increase is estimated in the incidence of hospitalisation by 36%, 40% and 29% due to diabetes mellitus, hypertensive disease and ischaemic heart disease, respectively, in 2010 as compared to 2005. The greatest burden and the largest increase in the rate of hospitalisation will be due to hypertensive disease. CONCLUSIONS: There will be an exponential increase in hospitalisation due to diabetes, hypertension and ischaemic heart disease. The health sector should provide additional resources to meet the demand.

Diabetes Mellitus↗
PubMed2005

Morbidity pattern and household cost of hospitalisation for non-communicable diseases (NCDs): a cross-sectional study at tertiary care level.

OBJECTIVE: To determine the pattern of morbidity and the demographic and socioeconomic characteristics of patients seeking in-patient services for noncommunicable diseases (NCDs) in medical units of a tertiary care hospital, and to estimate the economic burden imposed by these admissions on the households. METHODS: A descriptive cross-sectional study was conducted in medical units of the Colombo North Teaching Hospital, Ragama. Data were collected using a pre-tested interviewer-administered questionnaire. Morbidity patterns and demographic and socio-economic characteristics of patients with NCDs were determined. Direct and indirect components of the household cost of hospital stay were estimated. RESULTS: Fifty five per cent of the patients men male and the largest age group (11%) was 50-54 years. Seventy per cent were above 40 years of age, and 63% represented social classes 4 and 5. Diseases of the circulatory system were the commonest (31%). Median household cost of the total hospital stay was Rs. 852.00 (inter-quartile range Rs. 351.00-1885.00) of which 70% were direct costs. Median daily cost was Rs. 340.00 (interquartile range Rs.165.00-666.00). Only 44% of patients incurred an indirect cost. Cost of travelling was the main contributor (36%) to the household cost. Laboratory investigations contributed 16%. CONCLUSIONS: Most patients seeking in-patient services were from a poor socioeconomic background. The economic burden imposed by the admission to the household was mainly due to direct costs incurred for travelling and investigations.

Adolescent↗
PubMed2004

A cost analysis of the use of the rapid, whole-blood, immunochromatographic P.f/P.v assay for the diagnosis of Plasmodium vivax malaria in a rural area of Sri Lanka.

Between May 2001 and March 2002, a prospective study was conducted in a malaria-endemic area of Sri Lanka, to determine the cost implications of using the immunochromatographic P.f/P.v test to detect Plasmodium vivax infection. All consecutive subjects aged >5 years who presented with a history of fever were recruited. Each was checked for P. vivax infection by the standard microscopical examination of bloodsmears and by the immunochromatographic test (ICT). The costs of diagnosis using each method and the sensitivity, specificity and predictive values of the ICT (with bloodsmear examination used as the 'gold standard') were estimated, the costs/case detected being simulated for different slide positivity 'rates' and ICT sensitivities. In the detection of P. vivax, the ICT had a sensitivity of 70% and a specificity of 99%. The costs of the ICT per subject investigated and per case detected were, respectively, approximately 14 and 20 times more than those of bloodsmear examination. The costs of the ICT per case detected would fall as the sensitivity of the test increased. The ICT gave relatively few false-positive results. The current, relatively high cost of the ICT is the most important barrier to its routine operational use in the diagnosis of malaria. The test is already useful, however, in specific situations.

Adolescent↗
PubMed2003

Seroprevalence of rubella antibodies among pregnant females in Sri Lanka.

The purpose of this study was to determine the seroprevalence of rubella antibodies among pregnant females in the Kalutara District of Sri Lanka, and to identify factors associated with susceptibility to rubella infection among pregnant females. A cross-sectional clinic-based study was conducted among 620 pregnant women attending antenatal clinics and residing in the district for more than one month. Data on the pregnant females and the socio-economic characteristics of the families were obtained using an interviewer-administered structured questionnaire. Three milliliters of blood was obtained to measure rubella-specific IgG antibody levels by ELISA (enzyme linked immunosorbent assay) tests. Overall, 76% of pregnant females were seropositive for rubella antibodies. Seropositivity in pregnant females increased with age. Susceptibility to rubella was significantly associated with rubella immunization status. Given the high susceptibility rate to rubella infection among pregnant females, it is imperative that any vaccination strategy in the short-term should focus on reducing the number of susceptible women of child-bearing age.

Antibodies, Viral↗
PubMed2003

The impact of repeated malaria attacks on the school performance of children.

The impact of repeated malarial infections on the school performance of children was investigated in 571 school children 6-14 years of age in a malaria-endemic area in southern Sri Lanka where both Plasmodium falciparum and P. vivax infections are prevalent. Malaria infections confirmed by microscopy were monitored over a six-year period. School performance was assessed by two specially designed, school grade-specific, test papers for Sinhala language and mathematics. The scores for Sinhala language and mathematics for each school term test for the year 1997 were obtained. Malarial infections were a major predictor of children's performance in language and mathematics after controlling for parent's education, monthly family income, and house type. The education of the father predicted language scores but not mathematics scores. A child who experienced more than five attacks of malaria scored approximately 15% less than a child who experienced less than three attacks of malaria. The data suggest that repeated attacks of malaria have an adverse impact on the school performance of children.

Adult↗
PubMed2002

Strategies for immunisation against rubella: evidence from a study in the Kalutara District.

OBJECTIVE: To simulate different immunisation programs against rubella and estimate the proportion of the population susceptible to rubella infection of each. METHODS: The impact of 3 immunisation schedules on the susceptibility of women of childbearing age and the community to rubella infection was simulated using a probabilistic approach. The first schedule involved selective immunisation of 12-year old girls, the second immunisation of all children at 3 years of age for different immunisation coverages, and the third comprised a combination of the first two. The proportion of different segments of the population currently susceptible to rubella was obtained from a field study conducted in the Kalutara District in 1999. RESULTS: An immunisation program of 12-year old girls will reduce the susceptibility to rubella in 5 years in only the 15 to 19 year age group. In 10 years, the susceptibility in both the 15 to 19 and 20 to 24 year age groups will be reduced. Immunisation only of children at 3 years will take 20 years for a reduction in the susceptibility to rubella infection in the 15 to 19 year and the 20 to 24 year age groups, and the proportion of the population susceptible to rubella can be reduced to less than 10% in 20 years if 90% coverage is attained. If a combination of the two strategies i.e. selective immunisation of girls at 12 years for 10 years and immunisation of all children at 3 years is adopted, the proportion of the community susceptible to rubella will be less than 14% in 10 years. CONCLUSIONS: The combination of immunising girls at 12 years of age for 10 years and all children at 3 years of age against rubella is recommended for Sri Lanka to reduce the risk of congenital rubella syndrome in the short term and the proportion susceptible to rubella in the community in the long term.

Adult↗
PubMed2002

A safety and efficacy trial of artesunate, sulphadoxine-pyrimethamine and primaquine in P falciparum malaria.

OBJECTIVE: To determine effectiveness and safety of the combination of artesunate, sulphadoxine + pyrimethamine and primaquine in the treatment of P falciparum malaria. DESIGN: A hospital based prospective study. SETTING: Base Hospital, Moneragala. METHODS: In 30 P falciparum infected patients admitted to the hospital, blood was taken for estimation of haemoglobin, white cell counts, and serum levels of aspartate aminotransferase, alanine aminotransferase, bilirubin and creatinine. They were administered artesunate, sulphadoxine + pyrimethamine (S + P) and primaquine on day 0 (artesunate 4 mg/kg, sulphadoxine 25 mg/kg, pyrimethamine 1.25 mg/kg and primaquine 0.75 mg/kg), and only artesunate on days 1 and 2 (artesunate 4 mg/kg each day). Blood was examined for malarial parasites, and patients were assessed on days 1, 2, 7, 14, 21 and 28. Patients assessed the severity of selected symptoms. Biochemical analyses were done on day 0 and repeated on days 7 and 28. RESULTS: Eight patients presented with fever which resolved in 7 patients in 48 hours. Asexual parasites were cleared in 80% of the 30 patients within 24 hours of treatment and in all 30 by day 7. Gametocytaemia cleared in all patients by day 14. There were no adverse effects experienced by the patients. The white cell and differential counts, liver enzymes and creatinine levels were within normal limits on all follow up days. CONCLUSIONS: The combination of artesunate, S + P and primaquine was found to be effective and safe in the treatment of uncomplicated P falciparum malaria.

Artemisinins↗
PubMed2002

Use of routinely collected past surveillance data in identifying and mapping high-risk areas in a malaria endemic area of Sri Lanka.

Stratification of malaria endemic areas on eco-epidemiological criteria is an important step in planning and implementing malaria control programs. The uses of stratification of malaria endemic areas lead to better targeting of control measures such as residual insecticide spraying in countries where unstable malaria transmission occur. In this study, two methods that can be used for stratification of malaria endemic areas in Sri Lanka using routinely collected surveillance data over a period of 9 years are described. In the first method, the median Annual Parasite Incidence (API) was used as the criterion to classify an area as at risk for malaria while in the second method, the API and the Falciparum Rate (FR) were used as the criteria. Risk maps were produced by plotting the results of the analyses on maps generated by EPIMAP. The potential uses of risk maps are discussed.

Data Collection↗
PubMed2001

Geo-helminth infections in a rural area of Sri Lanka.

School children carry the heaviest burden of morbidity due to intestinal helminth infection. The objective of this investigation was to study geo-helminth infections in 349 school children aged 6 to 13 years living in a rural area of Sri Lanka. Stool samples were examined by direct saline smear in an initial survey to determine the prevalence of intestinal parasitic infections and thereafter the children were followed up over a two year period with cross sectional surveys of stool samples being carried out at yearly intervals. Following collection of a stool sample, all the subjects were treated with mebendazole 500 mg as a single dose. Weights and heights were measured using standardized procedures. 2 ml of venous blood were collected from each subject under aseptic conditions to determine hematological indices. The prevalence of geo-helminth infections was low, and the prevalence declined during the two-year period from 5.4% in 1997 to 2.2% in 1998 and 2.0% in 1999 following yearly mass anti-helminth treatment. The incidence density was 0.021 cases per child year. The reduction in the prevalence from the baseline to the second survey is probably due to the reduction of the reservoir of infection among children as a result of mass treatment at baseline. The prevalence of infection during the second and third surveys were almost the same probably due to infections originating from other segments of the untreated population.

Adolescent↗
PubMed2000

The health and nutritional status of school children in two rural communities in Sri Lanka.

There is growing evidence of considerable burden of morbidity and mortality due to infectious diseases and undernutrition in school children. This study describes the nutritional status and parasitic infections of school children in two areas of rural Sri Lanka. All children in four primary schools in the Moneragala district of Sri Lanka were included in the study. The height and weight of children were measured and anthropometric indices calculated. Stool and blood samples were examined for evidence of intestinal helminthiasis, malaria and anaemia. A greater proportion of boys than girls were underweight, wasted and stunted. Over 80% of the children were anaemic but did not apparently have iron deficiency anaemia according to their blood picture. The prevalence of parasitic infections such as hookworm and Plasmodium spp that may contribute to anaemia was low.

Body Weight↗
PubMed1998

Malaria risk factors in an endemic region of Sri Lanka, and the impact and cost implications of risk factor-based interventions.

In an 18-month study of malaria in a population of 1,875 residents in 423 houses in an endemic area in southern Sri Lanka, the risk of malaria was found to be 2.5-fold higher in residents of poorly constructed houses than in those living in houses of good construction type. In residents of poorly constructed houses but not in others, the risk was even greater when the house was located near a source of water that could act as a potential breeding place for malaria vector mosquitoes (P = 0.0001). Based on previous findings that confirmed that house construction type was itself a risk determinant, and not merely a marker of other behavioral factors, we have estimated the potential impact of two feasible interventions to reduce the risk of malaria: 1) the imposition of a buffer zone of 200 meters around bodies of water from which houses of poor construction were excluded, which was estimated to lead to a 21% reduction of the malaria incidence in the overall population and a 43% reduction in the relocated community; and 2) the conversion of houses of poor construction type located in the buffer zone to those of a good construction type, which was estimated to lead to a 36% reduction in the incidence rates in the whole population and a 76% reduction in the residents of houses whose construction type was improved. Taking into consideration the cost to the Government of malaria prevention, we estimated the worth of a Government's investment in improving house construction type. The investment in housing was estimated to be offset in 7.2 years by savings to the Government on malaria costs alone, and beyond this period, to bring a return on the Government's investment by way of savings to the malaria control program.

Animals↗