Elimination of malaria from Sri Lanka and beyond; lessons for other countries in elimination phase

Elimination of malaria in 2012 was a major achievement in post-independent Sri Lanka. Sri Lanka missed a golden opportunity in 1963 when only 17 cases of malaria were reported in the country, but could not sustain the momentum resulting in a major resurgence in 1967/69. With the resurgence, the then malaria eradication programme was reverted back to a control programme that lasted for another 30 years. The WHO's Roll Back Malaria Initiative launched in 1998 provided a renewed interest in malaria control and subsequent elimination. With targeted control activities, the burden of malaria started to decrease since year 2000. Although Sri Lanka had reached pre-elimination status as early as 2004, the ongoing separatist war at that time prevented a country-wide elimination drive being implemented. With cessation of hostilities in 2009 and Global Fund financing, both of which were crucial inputs, an elimination drive was launched in September 2009 which eventually eliminated indigenous malaria in November 2012 with malaria-free certification by WHO being obtained in September 2016. Since malaria elimination, the country forged on to the prevention of re-establishment phase primarily focusing on good public practice that included intensified surveillance, both parasitological and entomological; quality assured diagnostic and treatment services; and advocacy at various level including doctors. Despite these measures, an introduced case and an induced case of malaria have been reported. A new vector of urban malaria, Anopheles stephensi, was reported in December 2016. Prevention of re-establishment of malaria should be kept in the radar of public health until malaria is eradicated.

Prevalence of asthma and its symptoms in Sri Lankan adults

BACKGROUND

Data on adult asthma is scarce in Sri Lanka. The objective of this study was to estimate the prevalence of asthma and its symptoms in adult Sri Lankans.  METHODS: A cross-sectional study using a translated version of the European Community Respiratory Health Survey screening questionnaire on subjects ≥ 18 years from 7 provinces in Sri Lanka was conducted. The asthma was defined as "wheezing in the past 12 months (current wheeze)", self-reported asthma attack in the past 12 months or on current asthma medication use.

RESULTS

Among 1872 subjects (45.1% males, 48.8% between 18-44 years of age), the prevalence of current wheeze was 23.9% (95%CI: 22.0%-25.9%), self-reported asthma was 11.8% (95%CI: 10.3%-13.2%) and current asthma medication use was 11.1% (95% CI: 9.6%-12.5%). The prevalences were higher in adults > 44 years, 31.4% positively responded to any of the above questions (95%CI: 29.3%-33.4%) and 60.9% of current wheezers did not report having asthma whilst 38.2% used asthma medication. Among current wheezers, 80.1% had at least one other symptom, cough being the commonest. Those with no current wheeze, self-reported asthma and on current asthma medication use, 30%, 35.9% and 36.6%, respectively, reported at least one other symptom. Smokers comprises 22% current wheezers, 20.6% of self-reported asthmatics and 18.7% of current asthma medication users.

CONCLUSIONS

The prevalence of asthma in Sri Lankan adults is higher than the other South Asian countries and higher in the older age group. A significant percentage of symptomatic individuals did not report having asthma or being on medication.

Validation of the World Health Organization/ International Society of Hypertension (WHO/ISH) cardiovascular risk predictions in Sri Lankans based on findings from a prospective cohort study

Introduction and objectives

There are no cardiovascular (CV) risk prediction models for Sri Lankans. Different risk prediction models not validated for Sri Lankans are being used to predict CV risk of Sri Lankans. We validated the WHO/ISH (SEAR-B) risk prediction charts prospectively in a population-based cohort of Sri Lankans.

Method

We selected 40–64 year-old participants from the Ragama Medical Officer of Health (MOH) area in 2007 by stratified random sampling and followed them up for 10 years. Ten-year risk predictions of a fatal/non-fatal cardiovascular event (CVE) in 2007 were calculated using WHO/ISH (SEAR-B) charts with and without cholesterol. The CVEs that occurred from 2007–2017 were ascertained. Risk predictions in 2007 were validated against observed CVEs in 2017.

Results

Of 2517 participants, the mean age was 53.7 year (SD: 6.7) and 1132 (45%) were males. Using WHO/ISH chart with cholesterol, the percentages of subjects with a 10-year CV risk <10%, 10–19%, 20%-29%, 30–39%, ≥40% were 80.7%, 9.9%, 3.8%, 2.5% and 3.1%, respectively. 142 non-fatal and 73 fatal CVEs were observed during follow-up. Among the cohort, 9.4% were predicted of having a CV risk ≥20% and 8.6% CVEs were observed in the risk category. CVEs were within the predictions of WHO/ISH charts with and without cholesterol in both high (≥20%) and low(<20%) risk males, but only in low(<20%) risk females. The predictions of WHO/ISH charts, with-and without-cholesterol were in agreement in 81% of subjects (ĸ = 0.429; p<0.001).

Conclusions

WHO/ISH (SEAR B) risk prediction charts with-and without-cholesterol may be used in Sri Lanka. Risk charts are more predictive in males than in females and for lower-risk categories. The predictions when stratifying into 2 categories, low risk (<20%) and high risk (≥20%), are more appropriate in clinical practice.

Assessing mental well-being in a Sinhala speaking Sri Lankan population: validation of the WHO-5 well-being index

Purpose

The WHO-5 well-being index is a widely used, short rating scale that measures subjective well-being. We translated the WHO-5 index into Sinhala and tested its psychometric properties including measurement invariance among diverse groups in a community sample in Sri Lanka.

Methods

The sample of 267 persons aged between 16 and 75 years was recruited from a semi-urban area. 219 completed a paper-based questionnaire and 48 responded to an online survey. Construct validity was tested for factorial validity (Confirmatory Factor Analysis -CFA), convergent validity and known group validity. Composite reliability for congeneric measures and test-retest reliability were also tested. Multi-group CFA (MG-CFA) was used to test measurement invariance.

Results

The translated Sinhala version demonstrated good content and face validity. Internal consistency reliability of the five items had a Cronbach’s alpha of 0.85 and test-retest reliability over 2 weeks was satisfactory (Pearson r = 0.72, p < 0.001, ICC = 0.82). Confirmatory factor analysis supported factorial validity with a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\chi}_5^2 $$\end{document}χ52 =4.99 (p = 0.28), a RMSEA of 0.03 (90% C.I. =0.00–0.10), a SRMR of 0.02, a TLI of 0.99 and a CFI of 0.99; factor loadings were between 0.55 and 0.89. Measurement invariance was acceptable for configural, metric and scalar invariance for gender.

WHO-5 scores were significantly negatively correlated with the Patient Health Questionnaire (PHQ-9) (Pearson’s r = − 0.45, p < 0.001) scores and the Kessler Psychological Distress Scale (K10) scores (Pearson’s r = − 0.56, p < 0.001).

Conclusion

The Sinhala translation of WHO-5 well-being index has shown acceptable psychometric properties and can be used for assessing mental well-being in the community in Sri Lanka. Further testing of the measure with larger and diverse (including different ethnic/cultural) groups are indicated to test measurement invariance of the measure.

Antenatal Care Provided and its Quality in Field Clinics in Gampaha District, Sri Lanka

A descriptive cross-sectional study was carried out in the Gampaha District in Sri Lanka to assess the quality of care provided at antenatal field clinics. Checklists were used to assess the structure and process attributes of quality. An interviewer administered questionnaire assessed the quality of information provided to the clients and client satisfaction. The findings indicated that several resource components need upgrading in the district. The majority of clinics did not have adequate seating arrangements, lacked a footstool, a height measuring instrument and Vitamin C. Less than 50% of the staff were present at 8.00 a.m. in eight clinics. Health education material was substandard in nine clinics. No supervisory notes were made during the preceding year in fourteen clinics. Testing urine for sugar and albumin was substandard in 11 and eight clinics, respectively. Physical examination of pregnant females was substandard in all 20 clinics. No information was provided on some routine procedures carried out at the clinic such as blood pressure monitoring, weight gain and vaccines given. Client satisfaction exceeded 95% in all aspects except building and infrastructure and time spent at the clinic. Asia Pac J Public Health 2007; 19(3): 38-44.

Translational research for Diabetes Self-Management in Sri Lanka: A randomized controlled trial

AIMS

The study tested the hypothesis that a theory driven Diabetes Self-Management (DSM) intervention delivered by trained nurses would result in a clinically significant improvement in glycaemic control.

METHODS

Patients with an HbA1c >7.5% (58mmol/mol) and free of diabetes complications were enrolled into a randomized controlled trial (n=85). Intervention consisted of four sessions and monthly follow up for 6 months. Biochemical tests, and diet and physical activity assessments were done in both groups. Analysis of covariance was used to test the effectiveness of the intervention.

RESULTS

At 6 months, there was a significant difference (P=0.001) in HbA1c between the groups controlling for baseline values and other variables. Based on the primary outcome, 28% in the intervention group achieved the target value of 6.5% HbA1c, compared to 8% in the "usual care" group (P<0.001; η(2)=0.65). The reduction in total energy intake and increase in physical activity was significant in the intervention group between baseline and follow up.

CONCLUSIONS

The DSM intervention has resulted in a clinically significant impact on glycaemia, change in diet and physical activity, and has demonstrated the feasibility of using it within existing care arrangements in a developing country setting.

Knowledge and perceptions of filariasis in Colombo, Sri Lanka, among patients with chronic filarial lymphoedema

Knowledge of filariasis and perceptions of the disease were explored among 413 lymphoedema cases attending two filariasis clinics in the Colombo district of Sri Lanka. The information was collected in interviews based on a pre-tested, interviewer-administered questionnaire. Only 15% of the patients had initially attributed their limb swelling to filariasis. Most knew that filariasis resulted from mosquito bites (81.1%) and that the disease is transmissible (59.8%) and preventable (74.3%). The majority did not know, or were uncertain, whether filariasis causes swelling of the breasts in females (68.5%), scrotal swelling (60.7%) or dry cough/breathlessness (62.7%). Most (60%) of the interviewees wrongly believed that chronic filarial lymphoedema could be cured, primarily by long-term treatment with diethylcarbamazine. Knowledge of filariasis was significantly associated with level of education (P<0.05). Curiously, compared with the male interviewees, the females interviewed were much less likely to say that filariasis was the cause of their initial swelling (P<0.001). Those who had suffered with the disease for more than 1 year were not significantly more knowledgeable about the disease than the interviewees who had developed symptomatic filariasis more recently. Knowledge about the symptoms of filariasis was generally poor in the study population. In order to dispel several common myths about the disease, health-education programmes, that are targeted both at the community in general and at primary-care providers, are clearly needed.

Community mobilization and household level waste management for dengue vector control in Gampaha district of Sri Lanka; an intervention study

Introduction

Waste management through community mobilization to reduce breeding places at household level could be an effective and sustainable dengue vector control strategy in areas where vector breeding takes place in small discarded water containers. The objective of this study was to assess the validity of this assumption.

Methods

An intervention study was conducted from February 2009 to February 2010 in the populous Gampaha District of Sri Lanka. Eight neighborhoods (clusters) with roughly 200 houses each were selected randomly from high and low dengue endemic areas; 4 of them were allocated to the intervention arm (2 in the high and 2 in the low endemicity areas) and in the same way 4 clusters to the control arm. A baseline household survey was conducted and entomological and sociological surveys were carried out simultaneously at baseline, at 3 months, at 9 months and at 15 months after the start of the intervention. The intervention programme in the treatment clusters consisted of building partnerships of local stakeholders, waste management at household level, the promotion of composting biodegradable household waste, raising awareness on the importance of solid waste management in dengue control and improving garbage collection with the assistance of local government authorities.

Results

The intervention and control clusters were very similar and there were no significant differences in pupal and larval indices of Aedes mosquitoes. The establishment of partnerships among local authorities was well accepted and sustainable; the involvement of communities and households was successful. Waste management with the elimination of the most productive water container types (bowls, tins, bottles) led to a significant reduction of pupal indices as a proxy for adult vector densities.

Conclusion

The coordination of local authorities along with increased household responsibility for targeted vector interventions (in our case solid waste management due to the type of preferred vector breeding places) is vital for effective and sustained dengue control.

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.

A Comparison between Revised NCEP ATP III and IDF Definitions in Diagnosing Metabolic Syndrome in an Urban Sri Lankan Population: The Ragama Health Study

Background. The prevalence of metabolic syndrome (MetS) within individual cohorts varies with the definition used. The aim of this study was to compare the prevalence of MetS between IDF and revised NCEP ATP III criteria in an urban Sri Lankan population and to investigate the characteristics of discrepant cases. Methods. 2985 individuals, aged 35-65 years, were recruited to the study. Anthropometric and blood pressure measurements and laboratory investigations were carried out following standard protocols. Results. Age and sex-adjusted prevalences of MetS were 46.1% and 38.9% by revised NCEP and IDF definitions, respectively. IDF criteria failed to identify 21% of men and 7% of women identified by the revised NCEP criteria. The discrepant group had more adverse metabolic profiles despite having a lower waist circumference than those diagnosed by both criteria. Conclusion. MetS is common in this urban Sri Lankan cohort regardless of the definition used. The revised NCEP definition was more appropriate in identifying the metabolically abnormal but nonobese individuals, especially among the males predisposed to type 2 diabetes or cardiovascular disease. Further research is needed to determine the suitability of the currently accepted Asian-specific cut-offs for waist circumference in Sri Lankan adults.

Musculoskeletal pain in four occupational populations in Sri Lanka

BACKGROUND

Factors influencing work-related musculoskeletal disorders might differ in developing and developed countries.

AIMS

To assess the prevalence and determinants of musculoskeletal pain in four occupational populations in Sri Lanka.

METHODS

As part of the international Cultural and Psychosocial Influences on Disability study, samples of postal workers, sewing machinists, nurses and computer operators were interviewed about pain at each of six anatomical sites in the past month, and about possible physical and psychosocial risk factors. Associations with prevalent pain were assessed by binomial regression.

RESULTS

Analysis was based on 852 participants (86% response rate). Overall, the lower back was the most common site of pain, with 1-month prevalence ranging from 12% in computer operators to 30% in nurses. Postal workers had the highest prevalence of shoulder pain (23%), but pain in the wrist/hand was relatively uncommon in all four occupational groups (prevalence rates ranged from 8% to 9%). Low mood and tendency to somatize were consistently associated with pain at all six sites. After adjustment for psychosocial risk factors, there was a higher rate of low back pain in nurses and postal workers than in computer operators, a higher rate of shoulder pain in postal workers than in the other occupational populations, and a relatively low rate of knee pain in computer operators.

CONCLUSIONS

Rates of regional pain, especially at the wrist/hand, were lower than have been reported in Western countries. As elsewhere, pain was strongly associated with low mood and somatizing tendency. Differences in patterns of pain by occupation may reflect differences in physical activities.

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.

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.

Costs and effectiveness of application of Poecilia reticulata (guppy) and temephos in anopheline mosquito control in river basins below the major dams of Sri Lanka

In this study we examined the costs and effectiveness of using larvivorous fish, Poecilia reticulata, and a chemical larvicide, temephos, in anopheline mosquito control in the riverbeds below the major dams in Sri Lanka. Five riverbeds below the dams, namely Laxapana, Kotmale 1, Kotmale 2, Nilambe, Rantembe and Victoria, were selected. Riverbed pools in Laxapana and Kotmale 1 were treated with P. reticulata; Rantembe and Victoria were treated with temephos; and Kotmale 2 and Nilambe were kept as controls. In each area, the anopheline larval density, before and after application of fish/temephos, was estimated. The cost of application of fish/temephos was estimated by activities involved for each treatment. After intervention, there was a significant reduction in anopheline larval density in the fish-treated areas compared with the temephos-treated and control areas. Application of P. reticulata was 2.67 times less costly than that of temephos. The cost of fish application can be further reduced if the community is involved in the application.

Efficacy of a limb-care regime in preventing acute adenolymphangitis in patients with lymphoedema caused by bancroftian filariasis, in Colombo, Sri Lanka

The efficacy of a programme of community home-based care (CHBC) for lymphoedematous limbs was evaluated among 163 lymphoedema patients attending two filariasis clinics in Colombo. Each patient was interviewed and examined and his or her lymphoedema was graded during a baseline assessment, before the CHBC programme, and again, during a post-intervention assessment, after the patient had been in the programme for 1 year. The number of patients having entry lesions was 24% lower at the post-intervention assessment than at the baseline (P<0.001), with a reduction in the frequency of each type of entry lesion investigated. In the year the patients were in the CHBC programme, 30% fewer of them experienced at least one attack of adenolymphangitis (ADL; P<0.001), the mean number of ADL attacks/patient was lower (P<0.001), and the mean duration of each ADL attack suffered was slightly shorter (5.70 v. 5.84 days; P>0.05) than in the year before the baseline assessment. The reduction in the incidence of ADL attacks was greatest in the patients with the higher grades of lymphoedema. Approximately 66% of the patients perceived an improvement in their swollen limb post-intervention. Eleven patients had grade-II lymphoedema at baseline but only grade-I lymphoedema after being on the CHBC programme for a year (P=0.012). The programme appeared to increase the frequencies with which patients followed each of the limb-care measures considered and most of the measures for the home management of ADL attacks that were investigated. It is recommended that the CHBC programme be implemented as a national programme in Sri Lanka.

Physical disability and psychosocial impact due to chronic filarial lymphoedema in Sri Lanka

Background

Information on the physical and psychosocial disability of lymphatic filariasis in Sri Lanka is scarce. Therefore this study was carried out to describe the physical disability and psychosocial impact associated with chronic lymphoedema in patients attending filariasis clinics in the Colombo district, Sri Lanka.

Methods

Four hundred and thirteen patients with lymphoedema of limbs attending filariasis clinics in Werahera and Dehiwala in the Colombo district were enrolled in the study after obtaining informed written consent. Data were collected using a pre-tested, interviewer-administered questionnaire and analyzed using SPSS.

Results

Majority (95%) of patients had lower limbs affected and there was a significant association with difficulty in walking (p = 0.023). The swollen limb affected the work of 87 (52 %) of employed patients and 26 persons reported loss of job. Approximately 25 % and 6 % reported having problems interacting with the community and family, respectively and 8.7 % felt that they were rejected by society. The swollen limb was perceived as a major problem by 36.8 % of patients. Of the married persons, 5.7 % and 6.2 % reported sexual and marital problems respectively, due to their swollen limb/s. Of those who had marital problems, 77.3% reported sexual problems as well (p < 0.001).

Conclusion

Lymphoedema significantly affects physical, psychological and social functioning in affected individuals. Morbidity control, in addition to control of physical disability, should target the psychosocial consequences.

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.

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.

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.

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.

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.

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.

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.

Cognitive performance at school entry of children living in malaria-endemic areas of Sri Lanka

In a cross-sectional study, carried out in January 1997 at the beginning of the school year, the impact of repeated attacks of malarial infection on the cognitive performance of children at school entry in moderate malaria-endemic areas of Sri Lanka was investigated. The cognitive performance of 325 schoolchildren in grade 1 (mostly aged 5-6 years) in 2 districts of Sri Lanka which are endemic for malaria (Anuradhapura and Moneragala) was assessed by an entry performance test developed by the National Institute of Education, Sri Lanka. The indices assessed included writing, language and mathematical skills. There was no difference in any of the cognitive performance indices between children from Anuradhapura and Moneragala districts. The scores of most of the indices decreased as the number of malaria infections experienced by a child increased and the ability to identify letters was significantly impaired by the number of malaria infections a child had experienced after controlling for socio-economic and nutritional status. These findings suggests that repeated attacks of malaria in children can have an adverse impact on their development.

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.

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.

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.

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.

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.

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.

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.

Clinical diagnosis of uncomplicated malaria in Sri Lanka

To assess the possibility of developing a protocol for the clinical diagnosis of malaria, a study was done at the regional laboratory of the Anti-Malaria Campaign in Puttalam, Sri Lanka. Of a group of 502 patients, who suspected they were suffering from malaria, 97 had a positive blood film for malaria parasites (71 Plasmodium vivax and 26 P. falciparum). There were no important differences in signs and symptoms between those with positive and those with negative blood films. It is argued that it is unlikely that health workers can improve on the diagnosis of malaria made by the patients themselves, if laboratory facilities are not available. For Sri Lanka the best option is to expand the number of facilities where microscopic examination for malaria parasites can take place.

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.

Optimizing the malaria data recording system through a study of case detection and treatment in Sri Lanka

The potential of using malaria incidence data routinely collected from endemic regions for disease control and research has increased with the availability of advanced computer-based technologies, but will depend on the quality of the data itself. We report here an investigation into the relevance of malaria statistics provided by the routine data collection system in Moneragala, a rural malaria-endemic region in Sri Lanka. All patients (n = 321) treated for malaria in 2 clusters of health care centres (HCCs) of both the private and the public sector in the administrative regions of Moneragala and Buttala Divisional Secretariat (D.S.). Divisions were studied in December 1995/ January 1996. The catchment area of these HCCs included a population resident in 53 Grama Niladhari (GN) areas, the smallest administrative units of the country. Almost equal numbers of malaria patients were detected and treated at Government and private health care institutions, and in 70% of them treatment was based on a diagnosis confirmed by microscopy. The routine data recording system, however, included only statistics from the Government sector, and only of patients whose diagnosis was microscopically confirmed. In compiling data, the origin of a case of malaria is attributed to the D.S. Division in which the institution (at which the patient was treated) was located, rather than the area in which the patient was resident, which was inaccurate because 90% of malaria patients sought health care at institutions located closest to their residence, thus crossing administrative boundaries. It also led to a loss of resolution of spatial data because patients' addresses recorded at the Government HCCs to the village-level are replaced in the statistics by the D.S. Division, which is a coarse spatial unit. Modifications to the system for malaria case recording needed to correct these anomalies are defined here. If implemented, these could result in major improvements to the quality of data, a valuable resource for the future of malaria control. The paper reiterates the call for the use of a standard spatial unit within a country to facilitate exchange of data among health and other sectors for the control of tropical diseases.

Early diagnosis and treatment of malaria in a refugee population in Sri Lanka

To provide early diagnosis and prompt treatment for malaria, two interventions were compared in refugee camps in Kalpitiya, Sri Lanka. Community health volunteers (HV's) were trained in diagnosis and management of malaria on clinical grounds, while a field laboratory was established in another group of camps providing treatment after laboratory confirmation of a malarial infection. Patients with fever sought treatment from HV's on average after 2.74 days and from the field laboratory after 3.20 days. Although acceptance of both interventions was high, the effective catchment areas, especially of the HV's were small. Large numbers of health volunteers would be needed to cover all families, making it difficult to sustain supervision and necessary logistic support. For every malaria patient treated by HV's, three others would receive anti-malarial drugs unnecessarily. The maintenance of a field laboratory with a microscopist of the Anti-Malaria Campaign is not an economically viable option. Training of HV's in microscopy with a mechanism for cost recovery should be given serious consideration. HV's and diagnosis and treatment centers should be able to handle a wide spectrum of common diseases. A better option for Sri Lanka in the short term might be to improve existing general health facilities that are accessible to the refugee population.

Development of the VIIIth nerve compound action potential evoked by low-intensity tone pips in the Mongolian gerbil

Maturation of the cochlea and afferent auditory units is reflected by changes in VIIIth nerve compound action potential (CAP) parameters. We studied auditory nerve CAPs evoked by low-intensity stimuli in Mongolian gerbils (Meriones unguiculatus) ranging in age from 22 to 92 days after birth. The gerbil CAP development is characterized by marked changes in latency, threshold, and amplitude during the first few weeks of life. CAP latency and CAP threshold reach adult-like values at about 1 month of age. In contrast, the CAP amplitude continues to grow in size even after 2 months. This dichotomy suggests that the development of afferent auditory nerve function in the gerbil is preceded by maturation of the mechanical processes of the middle ear and cochlea.

Development of contralateral suppression of the VIIIth nerve compound action potential (CAP) in the Mongolian gerbil

We studied whether same-frequency contralateral tones of 65 dB pSPL (peak Sound Pressure Level) suppress the VIIIth nerve compound action potential (CAP) evoked by 40-45 dB pSPL tone pips in the Mongolian gerbil from 22 to 92 days after birth (DAB). The primary stimuli were tone pips of 1, 2, 4, 8, and 10 kHz; only the 1 kHz CAP amplitude was suppressed significantly by tones of the same frequency. The suppression was seen at 22 DAB, and underwent little relative change with development.

Testing specific hypotheses by fitting underlying distributions to categorical data

The problem of estimating parameters and testing hypotheses pertaining to categorical data is well known in statistical analysis. Much of the literature on the subject specifies and fits linear models to multinomial data using methods such as weighted least squares. This article describes maximum-likelihood estimation and likelihood ratio tests for ordered categorical response variates with either discrete or continuous underlying probability distributions. Emphasis is on fitting and making inferences about parameters of mixture distributions, especially mixtures of normal distributions. Goodness-of-fit tests are given to check the adequacy of the fitted distributional models.

Birthweight and sociobiological factors in Ilorin, Nigeria

Social and biological factors influencing birthweight of 3053 Ilorin babies were studied. The mean birth weights were 2.998 kg +/- 0.133 (SD) for males and 2.932 kg +/- 0.154 (SD) for females. Multiple regression analysis showed that maternal weight, height, age, education and ethnicity, and child's sex, significantly affected birthweight of infants. Some quadratic and interaction terms also contributed significantly to the prediction of birthweight. The strategies to control the incidence of low birth weight are discussed.

Adolescent pregnancy: maternal weight effects on fetal heaviness: possible route to improved outcomes

In a previous report of a zinc supplementation trial in pregnant adolescents zinc effect varied according to maternal weight (wt) status--normal (90-110% of expected wt), light or heavy, prompting this analysis of effects of wt status and gestational wt gain on fetal heaviness relative to length and gestational age (GA) and other pregnancy outcomes. One-third of adolescents shifted in or out of normal wt by delivery, creating seven outcome groups--light-light, light to normal, normal to light, normal-normal, normal to heavy, heavy to normal, and heavy-heavy. These wt class change groups varied significantly as to intrauterine growth (SGA, low AGA, high AGA, and LGA); by weekly grams gain per cm height (ht), birth wt, infant wt/length ratio, and occurrence of low birth wt (LBW). Infants with above average intrauterine growth had an advantage in: absolute size, length of hospital stay, rates of LBW, fetal demise, rates of low Apgar score, and "other" complications. This association between intrauterine growth and maternal wt class change suggests that promotion of wt gain might lower rates of LBW. Birthwt varied by quartiles of weekly wt change (gm) per cm ht in women grouped by their percent of expected wt: in the lowest quartile (Q1) only one group in seven reached average Bwt (3025 grams); with Q4 gain all groups did. Thus, the parameter wt gain/wk/cm ht deserves study as a tool for monitoring wt status and gain to identify those pregnant adolescents in greatest need for nutritional counseling and to set wt gain goals.