Browsing by Author "Amarasekera, N.D.D.M."

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Allergic sensitization in children
(The Sri Lanka College of Paediatricians, 2008) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Weerasinghe, A.
BACKGROUND :Allergic sensitization is considered a significant risk factor for the development of atopic diseases. Appropriate allergen avoidance measures can be taken only when the pattern of sensitization to allergens in a particular population is known. No data is available regarding allergic sensitization among Sri Lankan children. OBJECTIVE: To identify the common allergens causing sensitization in a selected group of schoolchildren. DESIGN, SETTING AND METHOD: A cross-sectional study was carried out in 640 children in grade 5 (age group 9-11 years), from 17 schools in the Western Province. Data regarding atopic diseases was collected using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Specific IgE was estimated by ImmunoCAP method for five common aeroallergens (the dust mites Dermatophagoides pteronyssinus and Blomia tropicalis, cockroach, cat epithelium and dander, grass pollen) in a sub-sample of 203. RESULTS: Aeroallergen sensitivity was detected in 163 (80.3%) children. No significant difference for sensitization between boys and girls was noted (P= 0.549). The pattern of allergens in the two groups was similar. Mite allergen sensitivity was the most prevalent (B. tropicalis 84.0%, D. pteronyssinus 69.9%), followed by cockroach (67.5%), cat dander (46.0%) and grass pollen (35.6%). Twenty seven (13.3%) children were sensitized to all allergens tested; 28 (13.8%) children were sensitized to only one allergen; and 68.7% were sensitized to both B. tropicalis and D. pteronyssinus. Children with rhinitis or eczema (but not those with asthma) were significantly more likely to show sensitization to cat dander than asymptomatic controls (P=0.02 and P=0.002 respectively), but not to other allergens. The likelihood of being sensitized to one allergen was well correlated with sensitization to other allergens as evident by the significant correlation coefficients. CONCLUSION: Mites and cockroaches were the most common aeroallergens causing sensitization among schoolchildren in the Western Province.
Association between asthma and rhinitis
(Sri Lanka Medical Association, 2010) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Weerasinghe, G.A.K.
INTRODUCTION AND OBJECTIVES: It has been suggested that'both asthma and allergic rhinitis are manifestations of a single disease and they are related epidemiologically and pathophysiologically. The objective was to assess the relationship between asthma and allergic rhinitis in terms of serum total IgE (tlgE) and allergic sensiti-satipn in children. METHODS: Children attending grade 5 in 17 schools in the Western Province of Sri Lanka were recruited to the study. Data were collected using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Their serum total IgE (tlgE) and allergen-specific IgE (slgE) for five common aeroallergens (Dermatophagoides pteronyssinusr Blomia tropicalis, cockroach, cat epithelium and dander, grass pollen) were measured by ImmunoCAP method. RESULTS: A total of 640 schoolchildren were recruited. Their mean age was 10 years (SD ± 0.5) Prevalence (95% CI) of asthma and rhinitis was 17% (13.7-20.3) and 21.4% (17.8-25.1) respectively. Male preponderance was seen for both diseases, but was significant only for rhinitis. Among children with asthma, 44.4% had rhinitis. The geometric mean tlgE level was higher in children with asthma (804.6 kU/L) than with rhinitis (708.9 kU/L), but the difference was not statistically significant. Univariate analysis showed that sensitization to allergens from cat epithelium and dander was strongly associated with rhinitis (OR 2.104, 95% CI 1.1.16 - 3.969, P = 0.022) but not with asthma. CONCLUSION: Asthma and rhinitis appear to be different in our study population with respect to sensitising allergens and gender. The risk factors and development of these two diseases may vary in different populations.
Association between serum total IgE, allergic diseases and geohelminth infections in Sri Lankan children
(BioMed Central, 2007) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Douglass, J.; O’Hehir, R.E.; Weerasinghe, A.
BACKGROUND: Elevated levels of total IgE (tIgE) in serum are characteristic of allergic diseases. Levels of tIgE are influenced by genetic predisposition, age, sex and helminth infections. However, the association between tIgE and allergic diseases in children living in areas endemic for helminth infections is not clear. The aim of our study was to assess the relationship between tIgE, allergic diseases and geohelminth infections in children. METHODS: A total of 640 schoolchildren 9Y11 years of age was selected by stratified random sampling. Data regarding allergic diseases (asthma, rhinitis and eczema) were collected by a standard questionnaire given to the parent or guardian. Screening for helminth infections was done by examining their fresh stool samples by modified Kato-Katz technique. Serum tIgE was measured by Fluoroenzymeimmunoassay in 67 geohelminth-positive subjects and in a comparable group of geohelminth-negative subjects. RESULTS: The mean age in the study population was 10 years (SDT0.3). The prevalence of geohelminth infection was 15.5%. Trichuris trichiura (14.3%) was the most common followed by Ascaris lumbricoides (4.2%) and hookworm (0.2%). Mixed infection was detected in 20.3% of infected children. Infection intensity was light in 68.9% of infected children while 28.4% and 2.7% showed moderate and heavy infection respectively. The cumulative prevalence of allergic diseases was 33.7%. Prevalence of asthma, rhinitis and eczema was 17%, 21.4% and 5% respectively. Serum tIgE concentrations showed a positively skewed distribution. Geometric mean (GM) for tIgE for the geohelminth infected group (1039.9kU/L) was significantly higher than that of the non-infected group (575.4kU/L) (p = 0.004). It was also higher in the allergic group (933.3kU/L) than in the non-allergic group (639.7kU/L) but the difference was not statistically significant (p = 0.068). The GM for tIgE for non-allergic children in the study population was much higher than that seen in non-allergic children in developed countries. CONCLUSION: Serum tIgE concentration was strongly associated with the presence of geohelminth infections in children. Serum tIgE may not be a useful marker for allergic diseases in children living in areas endemic for geohelminth infections. © 2007 World Allergy Organization
Atopy, allergic diseases and soil transmitted nematode infections in children in Sri Lanka
(University of Kelaniya, 2009) Amarasekera, N.D.D.M.
Allergic diseases in children are a common paediatric problem affecting approximately one third of children worldwide. Attempts have been made to explain the rising prevalence of allergic diseases, of which the "Hygiene Hypothesis" gained much attention. Though an inverse association between a variety of infection and allergy has been demonstrated, the relationship between helminth infections and allergy remains unclear. A cross-sectional study was carried out in 640 school children selected by stratified random sampling from schools in the Western Province. Data regarding allergic diseases was collected using a validated questionnaire. Children were assessed for intestinal helminth infections by examining their stool samples using the modified Kato-Katz technique. Total IgE and specific IgE for a panel of five allergens (Dermatophagoides pteronyssinus, Blomia tropicalis, cockroach, cat dander and grass pollen) were studied using ImmunoCAP technique in a sub sample of 203. Prior exposure to Toxocara was determined using a commercially available ELISA kit, which detected IgG antibodies. A prevalence of 33.7% for allergic diseases (asthma, rhinitis and eczerna) was observed. Rhinitis was the commonest disease (21.4%). 15.5% of children had one or more intestinal nematode infections. 66.7% of children had antibodies indicative of prior exposure to Toxocara, while 30.6% had evidence of recent infection with Toxocara. Total IgE levels in our study population were intermediate between African and Western populations, but higher than other Asians. The levels were higher in children with intestinal nematode infections and those who were exposed to Toxocara. Total IgE correlated poorly with allergic disease status in the presence of helminth infections. 80.3% of children were found to be sensitized to one or more of the allergens tested; most commonly to dust mites. Children with rhinitis or eczema (but not asthma) were more likely to be sensitized to cat dander. No association was found between sensitization and helminth infections in our study population. Multivariate analysis using logistic regression showed that after adjusting for sex and atopy, children with intestinal nematode infections (especially trichuriasis) had a lower risk of having atopic diseases, especially asthma. Seropositivity for Toxocara spp. was not found to be associated with any atopic disease or atopy.
A Clinical guide for dengue detection, appropriate timing of investigations and hospital admissions
(Sri Lanka Medical Association, 2005) Premaratna, R.; Pathmeswaran, A.; Amarasekera, N.D.D.M.; Motha, M.B.C.; Perera, K.V.H.H.K.; de Silva, H.J.
Abstract Available.
A Clinical guide for early detection of dengue fever and timing of investigations to detect patients likely to develop complications
(Oxford University Press, 2009) Premaratna, R.; Pathmeswaran, A.; Amarasekera, N.D.D.M.; Motha, M.B.C.; Perera, K.V.H.K.K.; de Silva, H.J.
We aimed to identify clinical features that would be useful for case detection and the appropriate timing of investigations and hospital admissions in patients with short-duration fever, suspected to be dengue fever (DF). Of 928 adult patients with short-duration fever admitted to Colombo North Teaching Hospital, Sri Lanka during February-June 2004, one in four were randomly selected for assessment of the severity of six clinical features: headache, body aches, vomiting, retro-orbital pain, generalised weakness (scale 0-9) and skin erythema (grade 1-5). There were 148 DF patients (95 males, mean age+/-SD: 28+/-12 years) and 54 non-DF patients as controls (44 males, mean age+/-SD: 25+/-11 years). All symptoms assessed (cut-off >or=5) and skin erythema (>or=grade 2) had a good positive predictive value for DF. However, erythema had the best negative predictive value, helping to differentiate DF from other short-duration fevers. More than 95% of patients with dengue had a platelet count above 50000/microl until the third day of illness. The platelet counts were significantly reduced when erythema, fever, vomiting and generalised weakness were persistent. In conclusion, erythema elicited by hand impression may help in the prediction of DF, and follow-up blood counts are indicated when symptoms persist.
The Effect of intestinal nematode infections on atopic diseases in children
(Allergy and Immunology Society of Sri Lanka, 2009) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Douglas, J.; O'Hehir, R.; Weerasinghe, A.
BACKGROUND : The effect of helminth infections on atopic diseases and allergic sensitization is controversial. Little is known about the effect of infection on atopic diseases in children living in areas where both intestinal nematodes and Toxocara infections are prevalent. OBJECTIVE : To examine the association between atopic diseases and helminth infection among children exposed to both intestinal nematodes and Toxocara. METHODS: Children attending grade 5 (age group 9-11 years) in 17 schools in the Western Province of Sri Lanka were recruited. The association of atopic diseases (asthma, rhinitis, eczema) with active intestinal nematode infections (excreting eggs in faeces) and with exposure to Toxocara (specific IgG antibodies in serum) was investigated. A child was deemed sensitized if positive for at least one of the allergens tested (Dermatophagoides pteronyssinus, Blomia tropicalis, cockroach, cat epithelium, grass pollen), based on specific IgE levels in serum. RESULTS: A total of 640 children participated in the study; serum analysis was done in 203. Active intestinal nematode infection appeared to reduce the risk of atopic diseases (OR 0.47, P=0.016) whereas Toxocara exposure did not (OR 0.85 P=0.602). When specific IgE levels against Blomia tropicalis, the most common allergen in the study group (67.5%), were expressed as percentages of the total IgE levels for each child, infected children had significantly lower levels compared to uninfected children (P=0.001). CONCLUSIONS : Intestinal nematode infections seem to protect against atopic diseases in children in Sri Lanka. Polyclonal IgE synthesis may be involved in this protection.
Effect of mass chemotherapy for filariasis control on soil-transmitted helminth infection in Western Province of Sri Lanka
(The Royal Society of Tropical Medicine and Hygiene, 2007) Gunawardena, N.K.; Amarasekera, N.D.D.M.; Pathmeswaran, A.; de Silva, N.R.
In July 2006, Sri Lanka completed five rounds of annual mass drug administration (MDA) with diethylcarbamazine citrate and albendazole as part of its national programme for elimination of lymphatic filariasis. Albendazole is also highly effective against soil-transmitted helminths (STH). This study was carried out to assess the impact of repeated annual MDA on STH infections in the Western Province of Sri Lanka, an area that is co-endemic for lymphatic filariasis and STH. A total of 17 schools in the Western Province were selected because they were included in a national survey of the health of school children in Grade 5 in 2003, when one round of MDA had been completed. Faecal samples were obtained again in 2006 (after five rounds of MDA), from one randomly selected class of Grade 5 students in the same schools. In both surveys, faecal samples were examined using the modified Kato-Katz technique. The prevalence and intensity of roundworm, whipworm and hookworm infections in 2003 and 2006 were compared using chi-square or Z-test for a difference between two percentages. Faecal samples from 255 children were examined in 2003; 448 were examined in 2006. Roundworm prevalence was marginally lower in 2006 (4.0%) than in 2003 (4.7%), as was hookworm (0.2% vs 0.4%) whereas whipworm prevalence was higher (13.8% vs 9.4%). Mean egg counts for all three infections were marginally higher in 2006. However, none of these differences were statistically significant. Compliance with MDA in 2006, as reported by the school children examined, was only 59%. These results indicate that four annual roundsof MDA with diethylcarbamazine and citrate and albendazole had virtually no impact on STH infections in the study area. It is likely that inclusion of of albendazole in MDA for lymphatic filariasis does not have much impact on STH infections in areas of low endemicity, unless very high coverage rates are achieved.
Effect of repeated mass chemotherapy for filariasis control on soil-transmitted helminth infections in Sri Lanka
(Sri Lanka Medical Association, 2008) Gunawardena, N.K.; Amarasekera, N.D.D.M.; Pathmeswaran, A.; de Silva, N.R.
BACKGROUND: In July 2006 Sri Lanka completed 5 rounds of annual mass drug administration (MDA) with diethylcarbamazine citrate (DEC) and albendazole as part of its national programme for elimination of lymphatic filariasis (LF). Albendazole is highly effective against soil-transmitted helminths (STH). This study was carried out to assess the effect of repeated annual MDA on STH infections in the Western Province of Sri Lanka, an area co-endemic for LF and STH. METHODS: Faecal samples were obtained (during August-September 2006), from grade 5 students in 17 schools in the Western Province that were included in a national survey of schoolchildren's health in 2003, and examined using the modified Kato-Katz technique. The prevalence and intensity of roundworm, whipworm and hookworm infections in 2003 and 2006 were compared. RESULTS: Faecal samples from 255 children were examined in 2003; 448 were examined in 2006. Roundworm prevalence was marginally lower in 2006 (4.0%) than in 2003 (4.7%), as was hookworm (0.2% vs 0.4%), whereas whipworm prevalence was higher (13.8% vs 9.4%). These differences as well as that between the geometric mean egg counts were not statistically significant. Compliance with MDA in 2006, as reported by the schoolchildren examined, was only 59%. CONCLUSIONS: Four annual rounds of MDA with DEC and albendazole had virtually no effect on STH infections in the study area.
High serum total IgE in children in geohelminthic endemic setting
(Sri Lanka Medical Association, 2008) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Weerasinghe, A.
BACKGROUND: Elevated levels of total IgE (tlgE) in serum are characteristic of atopic diseases. However, the usefulness of tlgE in diagnosing atopic diseases in children living in areas endemic for helminth infections is not well established. OBJECTIVE: To assess the effect of geohelminth infections on serum tlgE levels in children with atopic diseases. DESIGN, SETTING AND METHODS: A total of 640 children in grade 5 were recruited from 17 schools in the Western Province. Data regarding atopic diseases were collected by a standard questionnaire. Screening for helminth infections was done by examining their stool samples by modified Kato-Katz technique. Serum tlgE was measured by fluoroenzymeimmunoassay. RESULTS: The mean age in the study population was 10 years (SD±0.3). The prevalence of geohelminth infection was 15.5%. Trichuris trichiura (14.3%) was the most common, followed by Ascaris lumbricoides (4.2%) and hookworm (0.2%). Mixed infection was detected in 20.3% of infected children. The cumulative prevalence of atopic diseases was 33.7%. Prevalence of asthma, rhinitis and eczema was 17%, 21.4% and 5% respectively. Geometric mean (GM) for tlgE for the geohelminth infected group (1039.9kU/L) was significantly higher than that of the non-infected group (575.4kU/L) (p=0.004). It was also higher in the allergic group (933.3kU/L) than in the non-allergic group (639.7kU/L) but the difference was not statistically significant (p=0.068). CONCLUSION: In the presence of geohelminth infections, raised IgE may be due to geohelminth infection or atopic diseases or both. Therefore, serum tlgE may not be a useful marker for allergic diseases in children living in areas endemic for geohelminth infections.
Impact of repeated mass chemotherapy for filariasis control on soil-transmitted helminth infections in Sri Lanka
(Sri Lanka Medical Association, 2007) Gunawardena, N.K.; Amarasekera, N.D.D.M.; de Silva, N.R.
INTRODUCTION: Under the national lymphatic filariasis elimination programme, five rounds of mass drug administration with diethylcarbarnazine citrate and albendazole were completed in July 2006. Albendazole is also highly effective against soil-transmitted helminths'^ STH). OBJECTIVE: To assess the impact of repeated annual mass chemotherapy with albendazole on STH infections in a co-endemic area. DESIGN, SETTING AND METHODS: Seventeen schools from among the State schools in the Western Province were selected because they were included in a national survey of the health of school children in Grade 5 in 2003. Fecal samples were obtained from one randomly selected class of Grade 5 students in each school in October 2006, and examined using the modified Kato-Katz technique. The prevalence and intensity of ascariasis, trichuriasis and hookworm infections in 2003 and 2006 were compared. RESULTS: Fecal samples from 448 children were examined in 2006, compared with 255 in 2003. Prevalence of ascariasis had declined marginally (18/448, 4.0% in 2006 vs 12/255, 4.7% in 2003), as had hookworm infection (1/448, 0.2%, vs 1/255, 0.4%), whereas the prevalence of trichuriasis had increased (62/448, 13.8% vs 24/255, 9.4%). Mean egg counts for all three infections were marginally higher in 2006 than in 2003. However, all these differences were not statistically significant. Reported compliance with MDA 2006 was 58.6%. Conclusions: The prevalence and intensity of STH infections among schoolchildren in the Western Province have not improved much despite annual mass drug administration with albendazole.
Prevalence of atopic diseases among school children in Western Province
(University of Kelaniya, 2007) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Weerasinghe, A.
Background : Atopic diseases such as asthma, rhinitis and eczema in children are major public health problems in developed, industrialized countries as well as in some developing countries. Our objective was to assess the prevalence of atopic diseases in schoolchildren in grade 5 in the Western Province of Sri Lanka. Method : Schoolchildren in grade 5 were selected by stratified - random sampling frbm 17 schools in the Western Province. Internationally validated ISAAC (International Study of Asthma and Allergies in Childhood) questionnaire, filled by the parent or guardian was used to collect details regarding atopic diseases. Results : A total of 640 schoolchildren were recruited. Five hundred ~nd eleven (79.8%) returned the completed questionnaire. The mean age was I 0 years (SD ± 0.3) and 55.9% of the study population was boys. Prevalence of asthma, rhinitis and eczema was 17%, 21.4% and 5% respectively, while 33.7% had one or more diseases, Thirty three (21.4%) of the children with an atopic disease was on long term treatment. Only the prevalence of allergic rhinitis showed a statistically significant difference between the two sexes, being more common in boys. Less than 30% of affected children's parents recognized that their child had either asthma or rhinitis, whereas a higher number of parents (54.2%) recognized that their child had eczema. Among children with asthma, 44.4% had rhinitis and wheezing was severe enough to disturb their sleep in 52.4% of children. Conclusion: One in 3 children in grade 5 had either asthma or rhinitis or eczema, but parental recognition of these conditions was poor. Atopic diseases are a significant health problem among schoolchildren in the Western Province.
Prevalence of childhood atopic diseases in the Western Province of Sri Lanka
(Sri Lanka Medical Association, 2010) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Weerasinghe, A.
BACKGROUND: Atopic diseases in children are major public health problems around the world and the prevalence is increasing. Our objective was to assess the prevalence of atopic diseases in schoolchildren in the Western Province of Sri Lanka. METHODS: Children attending grade 5 in 17 schools in the Western Province of Sri Lanka were recruited to the study. Data were collected using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, which was filled by the parent/guardian of the selected children. RESULTS: A total of 640 schoolchildren were recruited. Their mean age was 10 years (SD +/- 0.5) and 55.9% of the study population was boys. Prevalence (95% CI) of asthma, rhinitis and eczema was 17% (13.7-20.3), 21.4% (17.8-25.1) and 5% (3.1-7.0) respectively, while 33.7% (29.6-37.9) had one or more diseases. Only the prevalence of allergic rhinitis showed a statistically significant difference between the two sexes, being more common in boys. Less than 30% of affected children's parents recognised that their child had either asthma or rhinitis, whereas a higher number of parents (54.2%) recognised that their child had eczema. Among children with asthma, 44.4% had rhinitis. CONCLUSIONS: The prevalence of atopic diseases in schoolchildren in grade 5 in the Western Province of Sri Lanka is as common as in other countries in the south Asian region. Parental recognition of these conditions was not satisfactory
Reduced risk of atopic diseases among schoolchildren infected with intestinal Nematodes
(Federation of Immunology Societies of Asia-Oceania, 2008) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Pathmeswaran, A.; Douglass, J.; O’Hehir, R.; Weerasinghe, A.
BACKGROUND: The effect of helminth infections on atopic diseases and allergic sensitization is controversial. Little is known about the effect of infection on atopic diseases in children living in areas where both intestinal nematodes and Toxocara infections are prevalent. OBJECTIVE : To examine the association between atopic diseases and helminth infection among children exposed to both intestinal nematodes and Toxocara. METHODS: Children attending grade 5 (age group 9-11 years) in 17 schools in the Western Province of Sri Lanka were recruited. The association of atopic diseases (asthma, rhinitis, eczema) with active intestinal nematode infections (excreting eggs in faeces) and with exposure to Toxocara (specific IgG antibodies in serum) was investigate. A child was deemed sensitized if positive for at least one of the allergens tested (Dermatophagoides pteronyssinus, Blomia tropicalis, cockroach, cat epithelium, grass pollen), based on specific IgE levels in serum. RESULTS : A total of 640 children participated in the study; serum analysis was done in 203. Active intestinal nematode infection appeared to reduce the risk of atopic diseases (OR 0.47, P=0.0I6) whereas Toxocara exposure did not (OR 0.85, P=0.602). When specific IgE levels against Blomia tropicalis, the most common allergen in the study group (67.5%), were expressed as percentages of the total IgE levels for each child, infected children had significantly lower levels compared to uninfected children (P=0.001). CONCLUSIONS : Intestinal nematode infections seem to protect against atopic diseases in children in the tropics. Polyclonal IgE synthesis may be involved in this protection.