Medicine
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/12
This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
Browse
5 results
Search Results
Item Sensitive and inexpensive molecular test for falciparum malaria: detecting Plasmodium falciparum DNA directly from heat-treated blood by loop-mediated isothermal amplification(American Association For Clinical Chemistry, 2006) Poon, L.; Wong, B.W.; Ma, E.H.; Chan, K.H.; Chow, L.M.; Abeyewickreme, W.; Tangpukdee, N.; Yuen, K.Y.; Guan, Y.; Looareesuwan, S.; Peiris, J.S.BACKGROUND: Malaria is one of the most important parasitic infections in humans. A sensitive diagnostic test for malaria that could be applied at the community level could be useful in programs to control the disease. The aim of the present work was to develop a simple, inexpensive moleculartest for Plasmodium falciparum. METHODS: Blood was collected from controls (n = 100) and from patients diagnosed with falciparum malaria infection (n = 102), who were recruited to the study. Heat-treated blood samples were tested by a loop-mediated isothermal amplification (LAMP) assay for P. falciparum. Results were interpreted by a turbidity meter in real time or visually at the end of the assay. To evaluate the assay, DNA from these samples was purified and tested by PCR. Results from the LAMP and PCR assays were compared. RESULTS: The LAMP assay detected P. falciparum directly from heat-treated blood. The quantitative data from the assay correlated to the parasite counts obtained by blood-film microscopic analyses. When we used the PCR assay as the comparison method, the sensitivity and specificity of the LAMP assay were 95% and 99%, respectively. CONCLUSIONS: Unlike PCR, the LAMP assay does not require purified DNA for efficient DNA amplification, thereby reducing the cost and turnaround time for P. falciparum diagnosis. The assay requires only basic instruments, and assay positivity can be verified by visual inspectionItem 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 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 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.