Browsing by Author "Fernando, D."

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Anaphylaxis: the “killer allergy”
(Ceylon College of Physicians, 2016) Wijekoon, C.N.; Undugodage, C.; Fernando, D.; Atapattu, P.; Malavige, G.N.; Ranawaka, U.K.
Aspirin is associated with low oral pH levels and antacid helps to increase oral pH
(Biomed Central, 2018) Ediriweera, D.S.; Dilina, N.; Saparamadu, V.; Fernando, I.; Kurukulasuriya, B.; Fernando, D.; Kurera, J.
OBJECTIVE: Aspirin is a commonly used medicine for primary and secondary prevention of cardiovascular diseases. It is an acidic medicine associated with gastric irritation and acid reflux, which in turn can lead to low oral pH levels. Therefore, it is important to understand the association between aspirin and oral pH levels in order to achieve an optimum oral health condition among patients who take aspirin on prescription. RESULTS: Out of 373 patients, 162 (44%) were males and 245 (66%) were on aspirin. 71% of aspirin taking patients and 29% of non-aspirin taking patients had oral pH less than 6.5 (P < 0.01). Aspirin showed a significant association with low oral pH levels (odds ratio = 1.91, 95% CI 1.23-2.99, P < 0.01). 78 patients were given antacids and followed up for 4 weeks, 63 of them (81%) showed an improvement in oral pH and the improvement was marked in the group who had oral pH between 5.5-6.0 compared to the group who had oral pH between 6.0-6.5 (P = 0.03). The results show that aspirin therapy is associated with low oral pH and administration of an antacid with aspirin helps to increase the oral pH level.
Biology, bionomics and life-table studies of Anopheles stephensi (Diptera: Culicidae) in Sri Lanka and estimating the vectorial potential using mathematical approximations
(Elsevier, 2023) Jude, J.; Gunathilaka, N.; Udayanaga, L.; Fernando, D.; Premarathne, P.; Wickremasinghe, R.; Abeyewickreme, W.
Background: Anopheles stephensi is an invasive mosquito in Sri Lanka that can potentially transmit malaria. The transmission intensity is linked with biology, bionomic and behavioral aspects of a vector that are associated with the Vectorial Capacity (VC). However, the influence of larval conditions eventually affects the vectorial potential of An. stephensi are not well understood. Methods: A colony of An. stephensi was established at the Regional Centre of the Open University of Sri Lanka, Jaffna District. The colony was maintained under confined conditions according to standard protocols. Biotypes of An. stephensi were characterized by referring to the number of egg ridges. Information on (a) biological aspects of eggs (duration for egg hatching, egg development and hatchability), (b) larval development time, larval survivorship pupation success, resting depth of larvae), (c) pupae (adult emergence rate, average time for adult emergence) and (d) adults (biting frequency, mating success gonotrophic cycle, fecundity, duration for egg-laying, percentage of sexes, adult survival/longevity) were evaluated under life-table analysis. Further, selected morphometric characters of each life cycle stage were recorded from the eggs (length and breadth), larvae (head length, width of head, length of thorax, width of thorax, length of abdomen, width of abdomen, and the total length of larvae), pupae (cephalothoracic length and width) and adults (length & width of wing, thorax and abdomen). The VC was calculated using a mathematical-based approach. Descriptive statistics, General Linear Model (GLM) and independent-sample t-test were used for the statistical analysis. Results: All three biotypes were identified based on egg morphology. Mysorensis biotype (47%; n = 470) was predominant followed by type (38.1%; n = 381) and intermediate (14.9%; n = 149). The mean egg length (F(2,997) = 3.56; P = 0.029) and breadth (F(2,997) = 4.57; P = 0.011) denoted significant differences among the three biotypes. The mating success of females observed was 80.7 ± 4.45%. The mean hatching period was 1.9 ± 0.03 days, with a hatching rate of 86.2 ± 0.77%. Overall, 8.0 ± 0.14 days were required for larval development and 30.3 ± 0.14 h were spent in the pupal stage. The pupation success was 94.5 ± 0.37%, and the majority were males (53.1 ± 0.73%). The mean fecundity was 106.5 ± 6.38 eggs and a gonotrophic cycle of 3.4 ± 0.06 days. The female survival rate was 43.2 ± 2.4%, with a mean biting frequency of 66.6 ± 3.5%. The average VC of adult An. stephensi was estimated to be 18.7. Conclusions: The type biotype, which is an effective vector in the Indian subcontinent is present in Sri Lanka. According to the mathematical approximation, An. stephensi found locally has a vectorial capacity of over 18. Therefore, this study warrants the health authorities and vector control programmes to continue the entomological surveys, monitoring of vector densities and implementing appropriate vector control interventions based on biology and bionomic information of vectors.
A case study on the prevailing maintenance and management system of the National Zoological Gardens of Dehiwala, through visitor perspective
(Department of Archaeology, University of Kelaniya, Kelaniya, 2017) Fernando, D.; Wijesundara, E.; De Silva, M.; Misaki, S.P.D.M.
Cognitive performance at school entry of children living in malaria-endemic areas of Sri Lanka
(Oxford University Press, 2003) Fernando, D.; Wickremasinghe, R.; Mendis, K.N.; Wickremasinghe, A.R.
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 suggest that repeated attacks of malaria in children can have an adverse impact on their development.
Comparative analysis of the larvicidal activity of temephos (EC50) and novaluaron (EC10) to control Anopheles stephensi in Sri Lanka
(Elsevier, 2023) Jude, J.; Gunathilaka, N.; Udayanga, L.; Fernando, D.; Premarathne, P.; Wickremasinghe, R.; Abeyewickreme, W.
Background: Anopheles stephensi was first recorded in the coastal area of Mannar District, Sri Lanka, in December 2016. Since then, this vector has been isolated from other districts in the Northern and Eastern Provinces of Sri Lanka. Chemical control is the main arm of vector control that can be used to reduce the vector densities within a short period. Thus, the present study aimed at evaluating the efficacy of using selected insecticides for the control of An. stephensi larvae. Method: The third and fourth instar larval stages of An. stephensi (F2 generation) of field mosquitoes that were caught using cattle baited net trap collections from Columbuthurai, Kurunagar, and Navanthurai areas in Jaffna District, Sri Lanka, were obtained from the laboratory colony established at Jaffna. Batches of 100 larvae were taken for experiments and introduced separately to a concentration series of temephos and novaluron (0.04-400 ppm). A control test was also performed at each setup without introducing insecticides. The mortality rates of An. stephensi larvae exposed to different concentrations of larvicides were recorded at 1, 24 and 48-h intervals. The experiment was replicated five times at individual concentrations for each selected chemical. Data were analyzed using the General Linear Model (GLM) and Probit analysis. Results: The highest mortality rate (100%) at a 1-h exposure period was observed from temephos at >100 ppm. The mortality rates varied significantly for different concentrations and larvicides (p < 0.05). At 24-h of the exposure period, the 100% mortality of An. stephensi larvae were observed from both temephos and novaluron even at 0.04 ppm. Conclusion: Both temephos and novaluron reported 100% mortality rates in An. stephensi larvae at 1-h and 24-h exposure periods. Based on the findings, temephos and novaluron can be recommended as effective larvicides for chemical-based control of An. stephensi in Jaffna, Sri Lanka. Further, it is recommended to conduct a field-based study, where habitat types and water quality are highly heterogeneous and may affect the residual activity.
A Comparative analysis of the outcome of malaria case surveillance strategies in Sri Lanka in the prevention of re-establishment phase
(BioMed Central, 2021) Gunasekera, W.M.K.T.A.W.; Premaratne, R.; Fernando, D.; Munaz, M.; Piyasena, M.G.Y.; Perera, D.; Wickremasinghe, R.; Ranaweera, K.D.N.P.; Mendis, K.
BACKGROUND: Sri Lanka sustained its malaria-free status by implementing, among other interventions, three core case detection strategies namely Passive Case Detection (PCD), Reactive Case Detection (RACD) and Proactive Case Detection (PACD). The outcomes of these strategies were analysed in terms of their effectiveness in detecting malaria infections for the period from 2017 to 2019. METHODS: Comparisons were made between the surveillance methods and between years, based on data obtained from the national malaria database and individual case reports of malaria patients. The number of blood smears examined microscopically was used as the measure of the volume of tests conducted. The yield from each case detection method was calculated as the proportion of blood smears which were positive for malaria. Within RACD and PACD, the yield of sub categories of travel cohorts and spatial cohorts was ascertained for 2019. RESULTS: A total of 158 malaria cases were reported in 2017-2019. During this period between 666,325 and 725,149 blood smears were examined annually. PCD detected 95.6 %, with a yield of 16.1 cases per 100,000 blood smears examined. RACD and PACD produced a yield of 11.2 and 0.3, respectively. The yield of screening the sub category of travel cohorts was very high for RACD and PACD being 806.5 and 44.9 malaria cases per 100,000 smears, respectively. Despite over half of the blood smears examined being obtained by screening spatial cohorts within RACD and PACD, the yield of both was zero over all three years. CONCLUSIONS: The PCD arm of case surveillance is the most effective and, therefore, has to continue and be further strengthened as the mainstay of malaria surveillance. Focus on travel cohorts within RACD and PACD should be even greater. Screening of spatial cohorts, on a routine basis and solely because people are resident in previously malarious areas, may be wasteful, except in situations where the risk of local transmission is very high, or is imminent. These findings may apply more broadly to most countries in the post-elimination phase. KEYWORDS: Active case detection; Malaria case surveillance; Malaria in Sri Lanka; Passive case detection; Prevention of re-establishment of malaria; Proactive case detection; Reactive case detection; Spatial cohorts; Travel cohorts; Yield.
Developmental responses and survival of Anopheles stephensi larval stages at different salinity levels
(Royal Society of Tropical Medicine and Hygiene, 2022) Jude, J.; Gunathilaka, N.; Udayanaga, L.; Fernando, D.; Premarathne, P.; Wickremasinghe, R.; Abeyewickreme, W.
BACKGROUND: Anopheles stephensi is a newly invaded vector in Sri Lanka. It has been identified in coastal areas in the northern and eastern parts of the country and evidences the ability to breed in brackish water environments. METHODS: Laboratory investigations were conducted with batches of 100 first and third instar larvae exposed to a salinity gradient (0-40 ppt). Survival rates at 1 h, 24 h and until pupation were recorded for first and third instar larvae at different salinity levels. The experiment was repeated four times for both instars. Data were analysed using the general linear model and probit analysis. RESULTS: Significant variations in adult emergence were observed from both larval stages at different salinity levels (p<0.05). The highest pupation rates were observed at 2.5 ppt salinity. The survival rate of first instar larvae after 24 h of salinity exposure was >80% up to 12.5 ppt, while 100% mortality was observed for from the ≥25 ppt level of salinity. More than 90% of the third instar larvae pupated from salinity levels <15 ppt. The lowest survival rate was reported as 15.8±2.47% at 25 ppt. CONCLUSIONS: This indicates a high potential of increasing density of A. stephensi in coastal ecosystems in lagoons and other saline water bodies. Hence it is high time to redesign vector control interventions for vector breeding in coastal ecosystems.
Distribution and seasonal variation of malaria vectors in the Mannar and Jaffna Districts; an entomological investigation during the phase of prevention of re-establishment of malaria in Sri Lanka
(Springer Link, 2024) Jude, J.; Gunathilaka, N.; Wijerathna, T.; Fernando, D.; Wickremasinghe, R.; Abeyewickreme, W.
Sri Lanka has been declared “malaria-free” since 2016. The presence vectors and the cent establishment of new vectors are key challenges. This study documents the distribution of malaria vectors in previously high malaria endemic areas in Sri Lanka. Three locations were selected in Mannar and Jaffna districts. Entomological surveillance was carried out during January 2019 to January 2020 in both districts using cattle baited net (CBNT), hand collection (HC), and larval collection. The variation of mosquito abundance with selected climatic variables were evaluated using Pearson’s correlation. A total of 44,526 anophelines belonging to 12 species was encountered from both districts. The CBNT was the most productive technique that represented 78.65% (n = 35,022) of the total collection. Anopheles subpictus was the predominant species among adult collections in both districts, while in larval surveys, An. stephensi (60.1%; n = 2963) and An. varuna (40.9%; n = 1026) were observed in Jaffna and Mannar districts, respectively. The adult density indicated significantly strong positive correlations to the rainfall (r = 0.619, P < 0.05) and humidity (r = 0.524, P < 0.05) in both Jaffna and Mannar (rainfall: r = 0.553, P < 0.05; humidity: r = 0.553, P < 0.05). The number of larvae was not directly correlated with climatic variables. The present study reports the presence of An. culicifacies, An. subpictus and An. stephensi. Considering the fact that imported malaria cases are reported across the country the fact that there is an entomological risk to transmit malaria locally is a challenge. This warrants the continuous monitoring of vector population and seasonal variation, especially in previous malaria endemic regions.
Effectiveness of passive case detection for imported malaria in a hospital setting in Sri Lanka during the prevention of re-introduction phase of malaria
(Oxford University Press, 2019) Dharmawardena, P.; Premaratna, R.; Mendis, K.; Wickremasinghe, A.R.; Rodrigo, C.; Harintheran, A.; Fernando, D.
INTRODUCTION: The effectiveness of the passive case detection (PCD) system for imported malaria was assessed in government hospitals in Sri Lanka post-elimination of malaria. METHODS: In 18 medical wards (test wards) in four government hospitals, the referral for malaria testing and the diagnosis of malaria by the ward physicians were monitored. Concurrently, in-ward febrile patients were assessed independently for their eligibility for referral for malaria diagnosis and were tested for malaria. The malaria incidence in 16 other wards (control wards), which the study did not screen, served as controls. RESULTS: Four imported malaria patients were diagnosed within the PCD system among 25 874 febrile patients admitted during the 14-month study period, two of whom were diagnosed in the test wards and two in the control wards. The study's screening programme did not detect any more malaria patients than detected by the routine PCD system of the wards. However, far fewer patients were screened for malaria (1.3%) than were eligible for screening (29.4%), and some infections were detected incidentally, rather than by a request for a malaria test. CONCLUSION: A continuous effort to maintain awareness of the disease among physicians would be required if the PCD system is to be effective for the detection of imported malaria, post-elimination.
Epidemiological profile of imported malaria cases in the prevention of reestablishment phase in Sri Lanka
(Taylor & Francis, 2022) Dharmawardena, P.; Premaratne, R.; Wickremasinghe, R.; Mendis, K.; Fernando, D.
ABSTRACT: Sri Lanka reported the last case of indigenous malaria in October 2012, and received malaria-free certification from WHO in September 2016. Malaria cases have since, shifted from indigenous to imported, and the country remains receptive and vulnerable to malaria. A case-based epidemiological study was conducted on all imported malaria cases reported in the country in 2015 and 2016 with the aim of profiling imported malaria to improve the effectiveness of the surveillance and case management system for malaria. Data were obtained from case reports of the Anti Malaria Campaign, hospital records and laboratory registers. Over the 2 years, 77 imported malaria infections were diagnosed in 54 Sri Lankans and 23 foreign nationals. A majority of the infections were reported among males (93%) in the age group of 21-50 years (85.8%), and all were recent travelers overseas. Most patients were detected by passive case detection, but 10% of cases were detected by Active Case Detection. Only 25% of patients were diagnosed within 3 days of the onset of symptoms. In 32% of patients, the diagnosis was delayed by more than 10 days after the onset of symptoms. Plasmodium falciparum infections manifested significantly earlier after arrival in Sri Lanka than did P.vivax infections. The majority of patients (74%) were diagnosed in the Western Province, which was not endemic for malaria. A third of patients were diagnosed in the private sector. The shift in the epidemiology of malaria infection from before to after elimination has implications for preventing the reestablishment of malaria. KEYWORDS: Imported malaria; case surveillance; delayed diagnosis; epidemiology; prevention of reestablishment; receptivity; risk factors.
Filarial antigens detected in urine using the immunochromatographic card test
(Sri Lanka Medical Association, 2006) Adikaram, N.D.; de Silva, N.R.; Fernando, A.; Fernando, D.; Lamabadasuriya, S.; Reid, C.B.
No Abstract Available.
First co-infection of malaria and hepatitis E diagnosed in Sri Lanka
(Sri Lanka Medical Association, 2023) Senarathne, S.; Rajapakse, S.; de Silva, H.J.; Seneviratne, S.; Chulasiri, P.; Fernando, D.
INTRODUCTION: Imported malaria cases continue to be reported in Sri Lanka. Similarly, hepatitis E is also considered a travel associated imported disease in Sri Lanka. This is a report of the first co-infection of malaria and hepatitis E in Sri Lanka. OBJECTIVES: A 21-year-old European who visited Sri Lanka after a 2 months stay in India, was admitted to hospital with fever, vomiting, abdominal pain, and dark-coloured urine on the 4th day after his arrival. On examination, he had splenomegaly but no hepatomegaly. He had thrombocytopaenia; 89% neutrophils; 9% lymphocytes; elevated liver enzymes and hyperbilirubinaemia. Urine was positive for bile pigment. METHODS: Considering his travel history to India, he was tested for malaria. The rapid diagnostic test became positive for Plasmodium falciparum while microscopy showed P. falciparum ring stages with a parasite density of 120/μl. He was treated as for uncomplicated P. falciparum malaria with oral Artemisinin-based Combination Therapy. The patient became fever-free and blood smears became negative after 13 hours following 2 doses of antimalarials. RESULTS: However, his liver functions were further deranged with apparent jaundice (ALT: 250 U/L; AST: 175 U/L; ALP: 130 U/L; GGT: 179 U/L; total bilirubin: 10.65 mg/dL; direct bilirubin: 8.08 mg/dL; indirect bilirubin: 2.57 mg/dL). Further blood tests detected hepatitis E-specific IgM antibodies. He was treated with oral ursodiol but no specific antiviral was given. Following the completion of antimalarials, he was discharged from the hospital upon clinical recovery. CONCLUSION: Clinicians should be vigilant on travel-associated co-infections in patients who are diagnosed with imported malaria.
The first introduced malaria case reported from Sri Lanka after elimination: implications for preventing the re-introduction of malaria in recently eliminated countries
(BioMed Central, 2019) Karunasena, V. M.; Marasinghe, M.; Koo, C.; Amarasinghe, S.; Senaratne, A.S.; Hasantha, R.; Hewavitharana, M.; Hapuarachchi, H.C.; Herath, H.D.B.; Wickremasinghe, R.; Mendis, K.N.; Fernando, D.; Ranaweera, D.
BACKGROUND:There has been no local transmission of malaria in Sri Lanka for 6 years following elimination of the disease in 2012. Malaria vectors are prevalent in parts of the country, and imported malaria cases continue to be reported. The country is therefore at risk of malaria being re-established. The first case of introduced vivax malaria in the country is reported here, and the surveillance and response system that contained the further spread of this infection is described.METHODS:Diagnosis of malaria was based on microscopy and rapid diagnostic tests. Entomological surveillance for anophelines used standard techniques for larval and adult surveys. Genotyping of parasite isolates was done using a multi-locus direct sequencing approach, combined with cloning and restriction fragment length polymorphism analyses. Treatment of vivax malaria infections was according to the national malaria treatment guidelines.RESULTS:An imported vivax malaria case was detected in a foreign migrant followed by a Plasmodium vivax infection in a Sri Lankan national who visited the residence of the former. The link between the two cases was established by tracing the occurrence of events and by demonstrating genetic identity between the parasite isolates. Effective surveillance was conducted, and a prompt response was mounted by the Anti Malaria Campaign. No further transmission occurred as a result.CONCLUSIONS:Evidence points to the case of malaria in the Sri Lankan national being an introduced malaria case transmitted locally from an infection in the foreign migrant labourer, which was the index case. Case detection, treatment and investigation, followed by prompt action prevented further transmission of these infections. Entomological surveillance and vector control at the site of transmission were critically important to prevent further transmission. The case is a reminder that the risk of re-establishment of the disease in the country is high, and that the surveillance and response system needs to be sustained in this form at least until the Southeast Asian region is free of malaria. Several countries that are on track to eliminate malaria in the coming years are in a similar situation of receptivity and vulnerability. Regional elimination of malaria must therefore be considered a priority if the gains of global malaria elimination are to be sustained.
The first reported case of co-infection of imported hepatitis E and Plasmodium falciparum malaria in Sri Lanka
(Sri Lankan Society for Microbiology, 2023) Senarathne, S.; Rajapakse, S.; de Silva, H.J.; Seneviratne, S.; Chulasiri, P.; Fernando, D.
Global travel and tourism, especially across tropical countries, may lead to importation of malaria and other infectious diseases into Sri Lanka. This case report describes the first co-infection of imported hepatitis E and Plasmodium falciparum malaria in a tourist diagnosed in Sri Lanka. The patient was initially diagnosed with uncomplicated P. falciparum malaria and was started on treatment with oral Artemisinin-based Combination Therapy (ACT). Deterioration of hepatic enzymes and hyperbilirubinaemia despite the rapid parasitological response to antimalarials led to further investigation and diagnosis of co-infecting hepatitis E in this patient. The importance of clinicians being vigilant on travel associated co-infections is highlighted to ensure early diagnosis and better patient management.
Genetic diversity of Leishmania donovani isolates from cutaneous lesions of military personnel in the Mullaitivu and Kilinochchi districts of the Northern Province, Sri Lanka
(Wolters Kluwer, 2022) Wijerathna, T.; Gunathilaka, N.; Semege, S.; Pathirana, N.; Rodrigo, W.; Fernando, D.
Objective: To compare the DNA sequences of Leishmania (L.) donovani isolated from individuals in two districts of the Northern Province with other parts of Sri Lanka and neighboring countries. Methods: Samples were collected from military personnel at the Army Hospital, Narahenpita, Sri Lanka from November 2018 to March 2020. A portion of the samples was fixed, stained with Giemsa and observed under the light microscope. The genomic The DNA was extracted from the remaining portion of the samples using DNEasy blood tissue kit (Qiagen, Germany) and amplified using Leishmania genus-specific primers for molecular diagnosis initially. DNA was amplified using L. donovani species-specific primers by PCR and the amplified product was sequenced for comparison of nucleotide sequences. Results: Out of 76 suspected patients, at least one biological sample of 45 (59.2%) was positive for L. amastigotes upon microscopy. Overall, 33 (43.4%) were positive in Leishmania genus-specific PCR, but only 23 (30.3%) were positive in L. donovani specific PCR. The dendrogram indicates that the current sequences clustered together with those from Nepal and Gampaha districts (Western Province), Sri Lanka, while the Indian and Eastern African sequences clustered separately. Conclusions: The genetic diversity was low among the isolates, indicating a single and possibly a local point of origin. However, the similarity of Sri Lankan and Nepal strains indicate a possibility of a shared point of origin, which needs more extensive evidence to confirm.
Genetic Polymorphism in Pvmsp-3a. and Pvcs genes in Plasmodium vivax infections in Sri Lanka
(Sri Lanka College of Microbiologists, 2008) Manamperi, A.; Fernando, D.; Mahawithanage, S.; Wickremasinghe, R*.; Bandara, A.; Wellawatta, C.; Hapuarachchi, C.; Abeyewickreme, W.; Wickremasinghe, R.
INTRODUCTION: Plasmodim vivax malaria accounts for about 70% of all malaria infections in Sri Lanka. There is limited information on the genetic heterogeneity of P. vivax parasites in endemic areas of the country. OBJECTIVE: The objective of this study was to assess the potential of two P. vivax genes, Pvmsp-3v. and Pvcs. as genetic markers for their use in genotyping parasites collected from the field. METHOD: DNA was extracted from 12 Geimsa-stained P. vivax positive slides by phenol/chloroform method. A nested polymerase chain reaction (PCR) approach was adopted for both Pvmsp-3a and Pvcs genes. RFLP analysis ofPvmsp-la nested PCR products was carried out with Hha\ restriction enzyme. RESULTS AND DISCUSSION: Nested amplification of the marker genes resulted in 4 size variants for Pvcs (~ 600-750 bp) and 2 size variants for Pvmsp-3a (1.9 kb and 1.1 kb). Further, all PCR-RFLP products of Pvmsp-3a. Gene showed a major size polymorphism. Three samples showed evidence of infections with mixed genotypes and there was also evidence to identify a relapse infection. Analysis of these two genetic markers revealed 11 distinguishable variant types: 4 for Pvcs and 7 for Pvmsp-3a. CONCLUSIONS: The observed PCR and PCR-RFLP profiles of the Pvcs and Pvmsp-3& genes demonstrate that the P. vivax parasites in Sri Lanka were highly diverse despite the prevailing low transmission levels. It could be concluded that these two genes in combination could be considered suitable genetic markers to analyze P. vivax parasite dynamics in Sri Lanka.
Genotyping of Plasmodium vivax infections in Sri Lanka using Pvmsp-3 alpha and Pvcs genes as markers:a preliminary report
(Malaysian Society of Parasitology and Tropical Medicine, 2008) Manamperi, A.; Sanath, M.; Fernando, D.; Wickremasinghe, R.; Anura, B.; Hapuarachchi, C.; Abeyewickreme, W.; Wickremasinghe, A.R.
Plasmodim vivax malaria accounts for more than 90% of malaria cases in Sri Lanka. There is limited information on the genetic heterogeneity of P. vivax in endemic areas of the country. Here we have assessed the potential of two P. vivax genes as genetic markers for their use in genotyping parasites collected from the field. DNA extracted from Geimsa-stained P. vivax positive slides were genotyped at two polymorphic loci: the P. vivax merozoite surface protein 3- alpha (Pvmsp-3alpha) and circumsporozoite protein (Pvcs). Analysis of these two genetic markers revealed 11 distinguishable variant types from the two genetic markers: 4 for Pvcs and 7 for Pvmsp-3alpha. The results indicate that the P. vivax parasite population is highly diverse in Sri Lanka, despite the low level of transmission.
Histopathology of cutaneous leishmaniasis caused by Leishmania donovani in Sri Lanka.
(Hindawi Pub. Co., 2020) Wijesinghe, H.; Gunathilaka, N.; Semege, S.; Pathirana, N.; Manamperi, N.; de Silva, C.; Fernando, D.
ABSTRACT: Cutaneous leishmaniasis (CL) is a neglected tropical disease that is gaining importance in Sri Lanka and internationally. The clinical presentation, pathology, and method of parasite elimination in CL vary according to the species. Leishmania donovani is the causative organism for leishmaniasis in Sri Lanka. This collaborative cross-sectional study describes the clinicopathological features of cutaneous leishmaniasis among personnel of the tri-forces serving in the North and East of the country. The histology of fifty cases of CL confirmed by at least two methods (slit skin smear, lesion aspirate, tissue impression, and histology) was reviewed. The parasitic load was assessed semiquantitatively. The histological features were correlated with the clinical presentation and organism load. The majority (89.8%; n = 44) presented with a single lesion mostly located in the upper limb (69.4%). The lesion types included papule (34.7%), nodule (32.7%), and an ulcer (30.6%). The evolution time of lesions averaged 31.55 weeks. Epidermal changes were observed in 49 of the biopsies and included hyperkeratosis (90.0%; n = 45), acanthosis (44.0%; n = 22), atrophy (34.0%; n = 17), and interface change (66%; n = 33). Dermal changes were seen in all cases and were characterized by a lymphohistioplasmacytic inflammatory infiltrate of variable intensity with ill-formed granuloma in 19 cases (38%) and well-formed epithelioid granulomas in 22 cases (44%). Focal necrosis was present in 20% (n = 10). Leishmania amastigote forms were observed in 88% (n = 44). Transepidermal elimination (P = 0.025), granuloma (P = 0.027) formation, and type of lesion (P = 0.034) were significantly associated with the organism load. Granuloma formation was associated with a reduction in organism load, indicating that the macrophage activation played an important role in the control of the organism.
Initial response to SARS-CoV-2 (COVID-19) outbreak in Sri Lanka; views of public health specialists through an International Health Regulations lens
(Public Library of Science, 2023) Caldera, A.; Wickremasinghe, R.; Newby, G.; Perera, R.; Mendis, K.; Fernando, D.
The COVID-19 pandemic affected Sri Lanka despite having developed an International Health Regulations (IHR) steering committee in 2016 and a national action plan for health security following the Joint External Evaluation in 2018. Many steps were taken to improve the disaster management skills of healthcare workers even before the COVID-19 outbreak. We interviewed seven public health specialists to obtain their views on the country's response to the pandemic. A thematic analysis was conducted, leading to the emergence of three major themes and seven subthemes. The major themes included health security preparedness; COVID-19 management; and effects of COVID-19. The subthemes were; preparedness prior to pandemic and gaps in the preparedness (under health security preparedness); dual burden for the curative sector, strategies to reduce transmission and barriers to managing COVID-19 (under COVID-19 management) and negative and positive effects of COVID-19 (under effects of COVID-19). When COVID-19 reached Sri Lanka, healthcare workers, border control authorities and those involved with infectious disease control were overwhelmed by the magnitude of the pandemic. Healthcare workers' hesitation to work amidst the pandemic due to fear of infection and possible transmission of infection to their families was a major issue; the demand for personal protective equipment by health workers when stocks were low was also a contributory factor. Lockdowns with curfew and quarantine at government regulated centers were implemented as necessary. Perceptions of the public including permitting healthcare workers to perform field public health services, logistical barriers and lack of human resources were a few of the barriers that were expressed. Some persons did not declare their symptoms, fearing that they would have to be quarantined. The pandemic severely affected the economy and Sri Lanka relied on donations and loans to overcome the situation. Pandemic also brought about innovative methods to maintain and upgrade health service provision. Individuals with non-communicable diseases received their regular medications through the post which reduced their risk of being infected by visiting hospitals. Improvement of laboratory services and quarantine services, a reduction of acute respiratory infections and diarrhoeal diseases, improved intersectoral coordination and public philanthropic response were other positive effects.