Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Extrathymic T cells in human malaria patients(Elsevier, 1998) Watanabe, W.; Weerasinghe, A.; Miyaji, C.; Sekikawa, H.; de Silva, N.R.; Gunawardena, S.; Ratnayake, H.; Kobayashi, J.; Thoma, H.; Sato, Y.; Abo, T.Item Clinical diagnosis of uncomplicated malaria in Sri Lanka(SEAMEO Regional Tropical Medicine and Public Health Project, 1998) van der Hoek, W.; Premasiri, D.A.; Wickremasinghe, A.R.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.Item Malaria risk factors in an endemic region of Sri Lanka, and the impact and cost implications of risk factor-based interventions(American Society of Tropical Medicine and Hygiene, 1998) Gunawardena, D.M.; Wickremasinghe, A.R.; Muthuwatta, L.; Weerasingha, S.; Rajakaruna, J.; Senanayaka, T.; Kotta, P.K.; Attanayake, N.; Carter, R.; Mendis, K.N.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 percent reduction of the malaria incidence in the overall population and a 43 percent 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 percent reduction in the incidence rates in the whole population and a 76 percent 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.Item Early diagnosis and treatment of malaria in a refugee population in Sri Lanka(SEAMEO Regional Tropical Medicine and Public Health Project, 1997) van der Hoek, W.; Premasiri, D.A.; Wickremasinghe, A.R.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 populationItem The ParaSightT-F dipstick test as a routine diagnostic tool for malaria in Sri Lanka(Oxford University Press, 1997) Kodisinghe, H.M.; Perera, K.L.R.L.; Premawansa, S.; Naotunne, T. de S.; Wickremasinghe, A.R.; Mendis, K.N.Blood from 1053 persons who presented for treatment at outpatient clinics of government health institutions in Sri Lanka, and 250 who took part in a blood survey for malaria, was examined by thick blood film microscopy under routine field conditions, and by the ParaSight-F dipstick method. All the samples were also examined microscopically under laboratory conditions when 4 times the number of microscope fields were examined. Compared with this reference standard, the sensitivity and specificity of the ParaSight-F test were 90.2% and 99.1%, and those of microscopy in the field were 92.4% and 98.4% respectively, there being no statistically significant difference between the 2 methods. The ParaSight-F test reading correlated significantly and positively with the intensity of clinical disease of patients but not with their peripheral parasitaemia, indicating that it may be a more accurate measure of the true parasite load than microscopy, which detects only parasites which are in the peripheral blood and not those which are sequestered in deep organs. The ParaSight-F test, however, failed to detect Plasmodium falciparum infections with only gametocytes in the blood (19.6% of the infected blood samples in this study). The time taken for a patient to revert to negativity by the ParaSight-F test was also significantly longer, up to 14 d. This would make the test unsuitable for checking the response to antimalarial treatment within 14 d. In an endemic area it would therefore fail to detect drug resistant populations of parasites.Item Optimizing the malaria data recording system through a study of case detection and treatment in Sri Lanka(Blackwell Scientific Publications, 1997) Abeysekera, T.; Wickremasinghe, A.R.; Gunawardena, D.M.; Mendis, K.N.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 percent 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 percent 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.Item Reversal of chloroquine resistance in malaria(The Kandy Society of Medicine, 1994) de Silva, H.A.No Abstract AvailableItem Unusual meuromuscular complications falciparum malaria(CAB International, 1994) de Silva, H.J.; de Silva, N.R.The involvement of the nervous system in Plasmodium falciparum malaria is a complex problem, and several mechanisms including mechanical obstruction of the microcirculation and immune mediated damage probably play a role in the pathogenesis. This review focuses attention on some of the more unusual neurological complications of falciparum malaria. Several neuropsychiatric manifestations have been reported during attacks of malaria and following use of antimalarial drugs.Item Absence of anti-Purkinje cell antibodies in patients with cerebellar ataxia following falciparum malaria(SEAMEO Regional Tropical Medicine and Public Health Project, 1994) de Silva, H.J.; Senanayake, N.Immunological mechanisms have been implicated in the pathogenesis of delayed cerebellar ataxia following falciparum malaria (DCA). We tested serum and CSF samples obtained from 39 Sri Lankan patients with DCA for the presence of antibodies (Ab) directed against cerebellar Purkinje cells by an immunofluorescence (IF) technique and Western blot analysis. For the IF test 7 mu thick frozen sections of histologically normal cerebellum obtained at post mortem were used. Proteins obtained from crude preparations of Purkinje cells isolated from the cerebellum were used for Western blot analysis. Sera obtained from patients known to have antineuronal antibodies associated with cerebellar degenerations and paraneoplastic disorders (anti-Hu and anti-Yo Ab) and sera from normal blood donors served as positive and negative controls, respectively. All serum and CSF samples obtained from patients with DCA were negative for Ab directed against cerebellar Purkinje cells. Humoral mechanisms are, therefore, unlikely to be important in the pathogenesis of this delayed complication of falciparum malaria.Item Possible chloroquine resistant P.vivax malaria in Sri Lanka(The Kandy Society of Medicine, 1993) de Silva, H.A.; de Silva, D.G.H.; Kodikaraarachchi, D.