Browsing by Author "Chandrasena, N."

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Abundance and taxonomic characterization of chigger mites (Acari: Trombiculidae and Walchiidae) associated with rodents in selected scrub typhus-prone areas in Southern and Western provinces of Sri Lanka
(University of Kelaniya, 2024) Liyanage, A.; Gunathilaka, N.; Premarathne, R.; Chandrasena, N.; Jacinavicius, F.D.C.; Silva, R.B.
Larval trombiculid mites (chiggers) are the vectors and reservoirs of the potentially lethal infectious disease, scrub typhus (ST) caused by Orientia tsutsugamushi. Small rodents are natural hosts of parasitic larval stage of the chigger mites. This study focused on determining the abundance of chigger mites associated with rodents in Sri Lanka and the taxonomic characterization of field-caught chiggers. Field sampling was conducted in the districts of Galle, and Hambantota of the Southern Province, and Gampaha of the Western Province, in 2019 and 2020. Sampling sites were selected according to the patient distribution. Rodents were captured using baited traps (7.62 cm x 7.62 cm x 25.4 cm) set up just before sunset at peri-domestic or work premises of ST fever patients. A total of 422 traps were placed at identified possible exposure locations in Galle (n=122), Hambantota (n=120) and Gampaha (n=178). A total of 58 small mammals were captured [Galle (n=19), Hambantota (n=7), and Gampaha (n=32)] under three small rodent species, namely; Rattus rattus (Black rat), Rattus norvegicus (Brown rat), Tatera indica (Indian gerbil), Gollunda ellioti (Indian bush rat) and Suncus murinus (Asian house shrew). The trapped rodents were anaesthetized with ketamine (75 mg/kg) /xylazine (10 mg/kg) and examined for larval mites. Mites detected were removed carefully with a brush, collected, and washed individually with 10% PBS and slidemounted in Hoyer’s medium. Chiggers were speciated morphologically by visual inspection and morphometry using a camera-mounted light microscope (x100). A total of 394 life stages of mites were collected. Three different genera were identified, including Leptotrombidium, Schoengastiella, and Microtrombicula. Leptotrombidium imphalum (72.59%; n=286) was the predominant species, followed by Schoengastiella punctata (8.12%; n=32). Some specimens were identifiable only up to genus level, Leptotrombidium sp. (3.55%; n=14) and Microtrombicula sp. (4.82%; n= 19). Some (7.11%; n=28) were not trombiculid mites, while 3.81%; n=15 was damaged beyond identification. Leptotrombidium imphalum was detected for the first time parasitizing the murids - Rattus novergicus and Tatera indica in the district of Galle, a new locality. In addition, S. punctata was recorded in a new locality in the Gampaha district, Western province with a new host association, Golunda ellioti. This study emphasizes the need for further entomological surveys in ST disease-endemic areas. Developing a morphological identification key for chigger mites in Sri Lanka is a top priority to facilitate field surveys.
Canine filaria species in selected lymphatic filariasis endemic and non-endemic areas in Sri Lanka
(Springer International, 2022) Rathnayake, S.; Chandrasena, N.; Wijerathna, T.; Mallawarachchi, H.; Gunathilaka, N.
Subperiodic brugian filariasis and dirofilariasis show a rising trend in Sri Lanka posing a threat to public health. As information was limited on canine filaria species in Sri Lanka, we studied the filaria parasites among dog populations in lymphatic filariasis (LF) endemic and non-endemic regions by microscopy and molecular methods. Thick blood smears (TBSs) were performed among 295 dogs presenting to veterinary clinics for surgical or sterilization procedures in Galle (LF endemic) and Mullaitivu (LF non-endemic) districts, of which 55.6% were positive for any microfilariae. We identified Dirofilaria repens (50.8%) and Brugia spp. (20.6%) by microscopy, which, included mono-infections (D. repens 35.3% and Brugia spp. 5%) and co-infections (15.6%). Infections in Galle and Mullaitivu were 61% and 44.9% respectively. The brugian filariasis rate was significantly higher among canines in LF endemic Galle district (29.9%) than in Mullaitivu (LF non-endemic) (1.1%) (P < 0.001), while D. repens infections were comparable in both districts. Genomic DNA extracted from 10% of microfilariae positive TBSs was amplified using pan-filarial primers targeting the internal-transcriber-spacer region-2 (ITS-2). Sequencing of amplicons confirmed the presence of D. repens (89.28%), Brugia pahangi (7.14%) and B. malayi (3.57%) infections. The phylogeny constructed and analysed in MEGA X indicated genetic variability among D. repens and B. pahangi isolates from Sri Lanka. With this study, we were able to report B. pahangi infections for the first time in Sri Lanka.
Descriptive Investigation of Strongyloidiasis Infection and Characterization of Strongyloides stercoralis Using Morphological and Molecular-Based Methods
(Hindawi Pub. Corp., 2020) Gunathilaka, N.; Chandrasena, N.; Wijerathna, T.; Fuji, Y.; Gunasekara, D.; Gunatilaka, R.P.; Premaratna, R.
ABSTRACT: Strongyloidiasis is caused by the nematode Strongyloides stercoralis which has the unique ability to reproduce and complete its entire life cycle within the human host through its autoinfection cycle. Diagnosis of this infection is important because of its potential to cause fatal hyperinfection syndrome or disseminated infections in those with defective cellular immunity. Parasitological methods based on faecal microscopy and culture often fail to detect low-intensity infections. A multiplex polymerase chain reaction (PCR) assay was developed for the detection of S. stercoralis, Ascaris lumbricoides, and Enterobius vermicularis by designing primers specific for the ITS1 region of ribosomal DNA of S. stercoralis and A. lumbricoides and 18S region of rRNA of E. vermicularis. A 61-year-old patient presented with chronic gastrointestinal and respiratory symptoms and weight loss with a stool microscopy positive for helminth larvae. Stool cultures with the Harada-Mori technique yielded L3 larvae which were identified as S. stercoralis based on morphology. The multiplex PCR performed on DNA extracted from stool elicited the expected band at 129 bp on gel electrophoresis of the PCR yield providing molecular evidence of intestinal strongyloidiasis. The patient's gastrointestinal symptoms improved with a six-day course of albendazole (400 mg twice daily). Negative posttreatment stool microscopy, culture, and PCR confirmed successful clearance of infection. Molecular-based PCR assay is a promising tool to diagnose and assess the therapeutic efficacy of anthelmintics in intestinal helminthiases such as strongyloidiasis.
Hospital-based study of the severity and economic burden associated with rotavirus diarrhea in Sri Lanka
(IOS Press, 2009) Chandrasena, N.; Rajindrajith, S.; Ahmed, K.; Pathmeswaran, A.; Nakagomi, O.
An investigation of a new cutaneous leishmaniasis endemic area in Western Sri Lanka
(Oxford University Press, 2021) Mallawarachchi, C.H.; Chandrasena, N.; Wijerathna, T.; Dalpadado, R.; Mallawarachchi, M.S.M.N.S.; Gunarathna, D.G.A.M.; Gunathilaka, N.
BACKGROUND: The aim was to investigate an emerging focus of cutaneous leishmaniasis (CL) in Gampaha district, Western Sri Lanka. METHODS: Sociodemographics of CL patients in Mirigama, Gampaha district, were compared with controls using a structured questionnaire. Clinical data and geographic positioning system coordinates of patients were recorded. Sandflies collections were performed in four selected sites using indoor hand collection (162 units) and cattle-baited net traps (n=3). RESULTS: Of 73 patients (mean age 43.6 y; SD 20), 58.9% were males. Lesions consisted of nodules (52.1%) and ulcers (47.9%). Single lesions were seen in 69.9% of patients, while 30.1% had multiple lesions. Except for one mucosal lesion, all the others were cutaneous. Treatment consisted of sodium stibogluconate and cryotherapy (46.6%), sodium stibogluconate (45.2%) or cryotherapy (8.2%). Multiple lesions were more likely to receive combination therapy (p=0.013). The majority of those employed (81.1%; 27/33) were engaged in outdoor work. Male gender, low education attainment and poor disease awareness were significant risk factors for CL (p<0.05). Four households reported multiple cases. Phlebotomus argentipes was detected in all cattle-baited net traps and 35.3% of indoor hand collection units. CONCLUSIONS: CL is emerging in Gamapha district with Mirigama as the epicentre. Case distribution indicates local transmission, with P. argentipes as the probable vector. KEYWORDS: Sri Lanka; cutaneous leishmaniasis; emerging infectious diseases.
Molecular characterization of culturable aerobic bacteria in the midgut of field-caught Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera mosquitoes in the Gampaha district of Sri Lanka
(Hindawi Pub. Co., 2020) Gunathilaka, N.; Ranasinghe, K.; Amarasinghe, D.; Rodrigo, W.; Mallawarachchi, H.; Chandrasena, N.
Background: Larval and adult mosquito stages harbor different extracellular microbes exhibiting various functions in their digestive tract including host-parasite interactions. Midgut symbiotic bacteria can be genetically exploited to express molecules within the vectors, altering vector competency and potential for disease transmission. Therefore, identification of mosquito gut inhabiting microbiota is of ample importance before developing novel vector control strategies that involve modification of vectors. Method: Adult mosquitoes of Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera were collected from selected Medical Officer of Health (MOH) areas in the Gampaha district of Sri Lanka. Midgut lysates of the field-caught non-blood-fed female mosquitoes were cultured in Plate Count Agar medium, and Prokaryotic 16S ribosomal RNA partial genes of the isolated bacteria colonies were amplified followed by DNA sequencing. Diversity indices were used to assess the diversity and richness of the bacterial isolates in three mosquito species. The distribution pattern of bacterial isolates between different mosquito species was assessed by Distance-Based Redundancy Analysis (dbRDA). Results: A total of 20 bacterial species (Staphylococcus pasteuri, Bacillus megaterium, Staphylococcus cohnii, Pantoea dispersa, Staphylococcus chromogenes, Bacillus aquimaris, Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus warneri, Moraxella osloensis, Enterobacter sp., Klebsiella michiganensis, Staphylococcus hominis, Staphylococcus saprophyticus, Streptomyces sp., Bacillus niacin, Cedecea neteri, Micrococcus luteus, Lysinibacillus sphaericus, and Bacillus licheniformis) were identified. All of these species belonged to three phyla, Proteobacteria, Firmicutes, and Actinobacteria, out of which phylum Firmicutes (71.1%) was the most prominent. The least number of species was recorded from Actinobacteria. The relative distribution of midgut microbes in different mosquito species differed significantly among mosquito species (Chi-square, χ 2 = 486.091; df = 36; P ≤ 0.001). Midgut microbiota of Cx. tritaeniorhynchus and Cx. gelidus indicated a similarity of 21.51%, while Ma. annulifera shared a similarity of 6.92% with the cluster of above two species. The gut microbiota of Cx. tritaeniorhynchus was also significantly more diverse and more evenly distributed compared to Ma. annulifera. Simpson's diversity, Margalef's diversity, and Menhinick's diversity indices were higher in Cx. gelidus. Of the recorded species, P. dispersa and strains of nonpathogenic species in Bacillaceaefamily (B. megaterium, B. niacini, B. licheniformis, and L. sphaericus) can be recommended as potential candidates for paratransgenesis. Conclusion: The relative distribution of midgut microbes in different mosquito species differed significantly among the three studied adult mosquito species. The present data strongly encourage further investigations to explore the potential usage of these microbes through paratransgenic approach for novel eco-friendly vector control strategies.
Morbidity management and disability prevention for lymphatic filariasis in Sri Lanka: Current status and future prospects
(Public Library of Science, 2018) Chandrasena, N.; Premaratna, R.; Gunaratne, I.E.; de Silva, N.R.
BACKGROUND: Sri Lanka was acknowledged to have eliminated lymphatic filariasis (LF) as a public health problem in 2016, largely due to its success in Mass Drug Administration (MDA) to interrupt disease transmission. Analysis of the Strengths, Weaknesses, Opportunities and Threats (SWOT) of the national Morbidity Management and Disability Prevention (MMDP) program, the other pillar of the LF control program, was carried out with the objective of evaluating it and providing recommendations to optimize the use of available resources. METHODOLOGY: A situation analysis of the MMDP activities provided by the state health sector was carried out using published records, in-depth interviews with key informants of the Anti Filariasis Campaign, site-visits to filariasis clinics with informal discussions with clinic workforce and personal communications to identify strengths and weaknesses; and opportunities to overcome weaknesses and perceived threats to the program were explored. The principal strength of the MMDP program was the filariasis clinics operational in most endemic districts of Sri Lanka, providing free health care and health education to clinic attendees. The weaknesses identified were the low accessibility of clinics, incomplete coverage of the endemic region and lack of facilities for rehabilitation. The perceived threats were diversion of staff and resources for control of other vector-borne infections, under-utilization of clinics and non-compliance with recommended treatment. Enhanced high level commitment for MMDP, wider publicity and referral systems, integration of MMDP with other disease management services and collaboration with welfare organizations and research groups were identified as opportunities to overcome weaknesses and challenges. CONCLUSIONS: The recommended basic package of MMDP was functional in most of the LF-endemic region. The highlighted weaknesses and challenges, unless addressed, may threaten program sustainability. The identified opportunities for improvement of the programme could ensure better attainment of the goal of the MMDP program, namely access to basic care for all affected by lymphatic filarial disease.
Parasitological screening of vector mosquitoes and molecular biological identification of larval filarial parasites among the wildcaught Mansonia mosquito species at selected areas in the district of Gampaha, Sri Lanka, a re-emerging focus of Brugian filariasis
(University of Kelaniya, 2024) Gunathilaka, N.; Wimalasiri, U.; Chandrasena, N.; Dalpadadu, R.
Brugian filariasis, a disease caused by the Protozoan parasiteBrugia malayi has re-emerged in Sri Lanka after nearly four decades of quiescence. The Brugia malayi that prevailed in Sri Lanka in the past was the nocturnal periodic human strain transmitted by mosquitoes of the genus Mansonia. The objective of the present study was the precise identification of vector mosquitoes and parasites of the current onset of the disease. Entomological surveys were performed during September/October 2021 in Ragama Medical Officer of Health area using cattle-baited net traps. Mansonia sp. mosquitoes were dissected to detect the presence of larvae of the parasite. The lysate of dissected mosquitoes positive for larvae was used for the extraction of genomic DNA of the parasite, which was subjected to Polymerase Chain Reactions (PCR) aimed at molecular speciation using pan-filarial primers specific for the internal transcribed spacer region two (ITS2) of the ribosomal DNA. A total of 1060 mosquitoes were tested, and that included seven mosquito species belonged to four genera. Culex gelidus (n=602; 56.8%) was detected as the predominant mosquito species followed by Armigeres subalbatus (n=420; 39.6%) Cx. tritaeniorynchus (n=2; 0.2%) and Anopheles nigerrimus (n=4; 0.4%). Mansonia spp. accounted for 2,7% of the total mosquito sample and among them, the presence of Mansonia annulifera was 1,2% of the total (n=20), Ma. uniformis was 0.9% (n= 10) and Ma. Indiana was 0.2% (n= 2). About 18.7% (n=6) of Mansonia mosquito collection was positive for filarial larvae. Among them, 15.6% (n=5) was Mansonia annulifera while (3.1%; n=1) was Ma. uniformis. The PCR products of all tested samples corresponded to the band size of 625 bp, specific to B. malayi confirming the identity of the parasite. Mansonia annulifera and Ma. uniformis were confirmed as vectors of the re-emerged B. malayi (nocturnally sub-periodic) in Gampaha district. The role of other mosquito vector species would require investigation by vector incrimination and xenomonitoring-based approaches.
A preliminary community survey of selected dengue patient households in the Ragama MOH, Gampaha District
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Wijegunawardana, N.D.A.D.; Gunathilaka, N.; Udayanga, L.; Gunawardene, N.; Dassanayake, R.; Chandrasena, N.; Bourtzis, K.K.; Abeyewickreme, W.
Socio-economic aspects of the local population has been found to directly influence the emergence of dengue epidemics. Thus, a preliminary community survey was conducted among 30 randomly selected dengue positive patient households in the Ragama Medical Officer of Health (MOH) area, in Gampaha District to assess the socio-economic and demographic level of the patients. Study premises were selected randomly based on the MOH records during the year of 2015 and the selection of the premises was purposely limited to Narangodapaluwa Public Health Inspector area that has reported the highest number of dengue cases. An interviewer administrated questionnaire was used for the collection of socio-economic and demographic aspects of the patient households. Among the selected households; 40% (n=12) had at least more than 2 dengue positive patients among the occupants, while 42 dengue positive patients were interviewed in total. Age distribution of positive patients ranged from 1 - 70 years, while mean and mode represented 35 and 19 years, respectively. Relative distribution of male to female ratio remained as 1:1. Around 50% of the patients had an educational level higher than intermediate school education (O/L). Based on the indirect questions regarding the possible factors affecting the DF transmissions, it was noted that only participants 26 out of 42 (61.90%), have been infected with DF more than once in their life time regardless of living in the same study area since birth. Twenty-two patients (52.38%) claimed that they believe, that the DF infection has acquired at home. Meanwhile others claimed (n=20, 47.68%) that possible DF infection acquired site could be outside environments, probably schools or the place of work. Cleanliness of the surroundings was maintained well at almost all households, while waste disposal was properly maintained at weekly intervals by urban council in 14 premises. Others practiced open ground burning twice a week. Most of the respondents were willing to support Aedes control measures and follow mosquito bite prevention methods (n=28, 93.33%). Majority of the households (n=21) were not satisfied with the government vector controlling activates within the area. There is no significant association between socio demographic and economic data with DF transmission within the study population. Relative abundance of Aedes mosquito population in existing rubber plantation could be a reason for the occurrence of high rate of DF cases. Thus, practice of effective integrated vector control measures within the study area is highly recommended for the controlling of dengue.
Prevalence of ectoparasitic infections and other dermatological infections and their associated factors among school children in Gampaha District, Sri Lanka
(Hindawi Publishing Corporation, 2019) Gunathilaka, N.; Chandrasena, N.; Udayanga, L.
Skin disorders are one of the commonest conditions among school children in developing countries. There are only a few published studies available from Sri Lanka on the prevalence of skin disorders. A community-based cross-sectional study was carried out among five government-run schools randomly selected from the district of Gampaha, Sri Lanka, during 2016-2017. A total of 41 students between 5 and 16 years of age were randomly selected from each school. Sociodemographic profile and hygienic behaviors of selected students were assessed using a pretested interviewer-administered questionnaire. Students were examined by a medical officer for the presence of different skin disorders. The chi-squared test of association and binary logistic regression were used for the identification of the significance of socioeconomic factors and hygienic practices among the study participants. A total of 205 school children participated in the study. The commonest skin disorder was pediculosis (42.0%; n=86), followed by dandruff (8.3%; n=17), fungal infections (6.8%; n=14), and scabies (1.5%; n=3). Almost one-fourth of the study participants (22.9%; n=30/131) had more than one disorder, majored by Pediculus captis infestation with dandruff. Over one-third (36.1%; n=74) were free of any skin disorders. The prevalence of skin disorders was significantly high among females (87.3%; n=110), compared to males (26.6%; n=21). Presence of long hair, higher family size, and limited number of rooms in the house were risk factors associated with the prevalence of skin disorders. The commonest skin disorder was pediculosis, while scabies and fungal infections were scarce among school children in the district of Gampaha, Sri Lanka. Implementation of health education and monitoring programs at the school level for maintaining the dermal health status of school children is recommended.
Public knowledge, practices and perceptions on typhus fevers in Southern Sri Lanka
(Wolters Kluwer Medknow Publications, 2022) Liyanage, A.; Chandrasena, N.; Gunathilaka, N.; Sanjeewa, R.; Premaratna, R.
Objective: To assess public knowledge, practices and perceptions on typhus fevers in Sri Lanka. Methods: A descriptive study was done in four selected typhus- prone areas in Southern Sri Lanka. A mixed-method was employed using face-to-face interviews and questionnaire-based surveys among confirmed cases of typhus and at-risk populations, respectively. Frequencies, percentages, and means were used to characterize socio-demography and evaluate disease awareness. Results: The lay terms for typhus fevers reported in the studied region were “peacock fever”, “tick fever” and “bird fever”. A total of 499 subjects participated [mean±SD, (45±16) years] in the questionnaire-based survey, and 13.6% (n=68) reported past experience of typhus fever, 1.2% (n=6) identified the disease as “typhus” while 58.7% (n=293) and 11.8% (n=59) knew it as ‘peacock fever’ and ‘tick fever’, respectively. The etiological agent was unknown to 95.2% (n=475), but 53.5% ((n=267) were aware that it was vector-borne. Fever (57.3%, n=286), eschar (35.7%, n=178), headache (22.0%, n=267) and myalgia (19.2%, n=96) were identified as key symptoms. Past disease experience was significantly associated with higher awareness of the main disease symptoms (fever: χ2=15.713, P<0.001; headache: χ2=19.447, P<0.001; lymphadenopathy: Fisher’s exact test, P=0.023; eschar: χ2=12.049, P<0.001). None knew of any disease prevention methods. Participants with a past history of typhus fever had sought treatment at state hospitals (55.9%, 38/68) and private sector hospitals (5.9%, 4/68). Conclusions: Public awareness on preventive practices for typhus fevers was rare among the participants though vector-borne aspect was known to many. Clinical disease awareness was deficient among those without past experience of typhus fever. Community sensitization on vector avoidance strategies is highly recommended.
Rickettsial disease IFA-IgG titres in Auto-Immune diseases; what do they imply?
(Sri Lanka Medical Association, 2016) Balasooriya, B.L.P.P.; Bandara, N.; Chandrasena, N.; Premaratna, R.
INTRODUCTION: Rickettsial infections are known to present mimicking autoimmune disorders. The gold standard diagnostic test for rickettsial diseases is based on the detection of IgM and or IgG antibodies against these infections by immuno-fluorescent technique (IFA). During the IFA test, patient sera containing anti rickettsial antibodies are made to react with rickettsial antigens that are grown in cell culture media. However, presence of nuclear material in these cell cultures may react with anti-nuclear antibodies that are produced in autoimmune disorders and cause a false positive immunofluorescent signal. OBJECTIVES: To evaluate the reactivity of rickettsial disease among patients with auto immunity diseases. METHOD: In order to evaluate the reactivity of rickettsial disease IFA-IgG test [IFA-IgG-OT (Orientia tsutsugamushi) and IFA-IgG-SFG (spotted fever group)] among patients with autoimmune diseases, an analytical cross-sectional study was carried out using sera of 38 patients with confirmed auto-immune diseases. RESULTS: The 38 patients included 15 systemic lupus erythematosus (SLE), 5 autoimmune-thyroiditis, 13 idiopathic-thrombocytopenia (ITP), 4 autoimmune-haemolytic-anaemia (AIHA), 1 polymyositis, 1 polyglandular syndrome and 1 Anti-phospholipid syndrome. The IFA-IgG reactivity of ≥ 1:128 was noted in 14/38 (37%); IFA-IgG-SFG in 7, IFA-IgG-OT in 3 and for both in 4. Of the 14 patients who had shown reactivity to IFA-IgG 2 had a titre of 1:128, four had a titre of 1:256, five had a titre of 1:512, three had >1: 1024 . 57% among the 14 who had shown reactivity were diagnosed as SLE, 21.4 % had ITP, 14.3% had AIHA, and 7.1% had polymyositis. None were diagnosed with thyroiditis. CONCLUSIONS: There was a significant reactivity of Rickettsial disease IFA-IgG assay in auto-immune diseases. Further studies are needed in order to ascertain whether this is due to recent rickettsial infections, false positive cross reactivity of autoimmune antibodies with rickettsial antigens or with cell culture nuclear antigens.
Rickettsial infection among military personnel deployed in Northern Sri Lanka
(BioMed Central, 2014) Premaratna, R.; Ariyaratna, N.; Attanayake, C.; Bandara, W.; Chandrasena, N.; de Silva, J.
BACKGROUND: Military personnel deployed in field actvities report on frequent tick bites. Therefore they may run the risk of exposure to rickettsial organisms. METHODS: In order to assess the risk of exposure to rickettsial organisms, two groups of military personnel who were deployed in field activities of Nothern Sri Lanka were investigated. The first group was studied in order to assess the sero-prevalence of rickettsioses and consisted of soldiers who were admitted following injuries during field activities. The second group was studied to identify the incidence of acute rickettsioses during their acute febrile presentations. They were tested with IFA-IgG against spotted fever group rickettsioses (SFG), scrub typhus (ST) and murine typhus. RESULTS: In the first group, 48/57 (84%) military personnel had serological evidence of exposure to rickettsioses (in all, IFA-IgG titer ≥ 1:128): 33/50 (66%) to SFG rickettsioses, 1/50 (2%) to ST and 14/50 (28%) had mixed titers for both (in all, titers were higher for SFG). While all of them were in military uniform most of the time and frequently slept on scrub land, 35/57 (61.4%) had never used insect repellents and none were on doxycycline prophylaxis. 48/57 (84%) had experienced tick bites during field activity. In the second group, there were 49 who presented with acute febrile illness with a mean duration of 8.5 days (SD 3.2). 33/49 (67.3%) were serologically positive for acute rickettsioses (IgG ≥1:256); 26 (79%) due to ST and 7 (21%) due to SFG rickettsioses, CONCLUSIONS: Exposure to rickettsial disease was common among soldiers who were deployed in Northern Sri Lanka. Scrub typhus was the predominent species accounting for acute febrile illness. Further studies are needed to understand the reasons for very high sero-prevalence for SFG rickettsioses with no anticedent febrile illness. Use of preventive measures was not satisfactory. The high sero-prevelence of SFG rickettsioses is likely to interfere with serological diagnosis of acute SFG rickettsioses in this population.
Toxoplasmosis awareness, seroprevalence and risk behavior among pregnant women in the Gampaha district, Sri Lanka
(London, UK : Maney Publishing., 2016) Chandrasena, N.; Herath, R.; Rupasinghe, N.; Samarasinghe, B.; Samaranayake, H.; Kasturiratne, A.; de Silva, N.R.
BACKGROUND: Primary gestational toxoplasmosis can be transmitted to the fetus with deleterious effects on the pregnancy. There is very little information regarding gestational toxoplasmosis in Sri Lanka. This survey was done to determine the prevalence and awareness of toxoplasmosis and to identify risk factors of infection among pregnant women in the Gampaha district, Sri Lanka. METHODS: Women attending obstetric clinics at the Colombo North Teaching Hospital in 2014 were tested for Toxoplasma gondii (T. gondii) specific Immunoglobulins G (IgG) and M (IgM) subtypes using the OnSite Toxo IgG/IgM Rapid Test-Dip Strip®. Disease awareness and risk behaviors of the participants were investigated. RESULTS: Of the 293 participants (mean age 27 years, SD ± 5.92), 38% were primigravidae with a mean gestational age of 16.2 weeks (SD 7). The prevalence of anti-T. gondii IgG and IgM antibodies was 12.3% (n = 36) and zero, respectively. Unadjusted and adjusted odds ratios were calculated to determine risk factors of infection (cat-ownership, handling cats, consumption of meat, commercial meals and unwashed raw vegetables and fruits, handling soil and not washing hands after handling soil). On bivariate analysis, eating commercially prepared meals weekly or more was associated with toxoplasma seroprevalence with marginal statistical significance. On multivariate analysis, none of the considered risk factors were significant. Toxoplasma awareness was 4.4% (n = 13); health personnel (46.2%, n = 6) and media (53.8%, n = 7) being sources of information. CONCLUSIONS: Health education programs to increase awareness of toxoplasmosis is recommended at antenatal clinics.
What clinicians who practice in countries reaching malaria elimination should be aware of: lessons learnt from recent experience in Sri Lanka
(BioMed Central, 2011) Premaratna, R.; Galappaththi, G.; Chandrasena, N.; Fernando, R.; Nawasiwatte, T.; de Silva, N.R.; de Silva, H.J.
Following progressive reduction in confirmed cases of malaria from 2002 to 2007 (41,411 cases in 2002, 10,510 cases in 2003, 3,720 cases in 2004, 1,640 cases in 2005, 591 cases in 2006, and 198 cases in 2007). Sri Lanka entered the pre-elimination stage of malaria in 2008. One case of indigenous malaria and four other cases of imported malaria are highlighted here, as the only patients who presented to the Professorial Medical Unit, Colombo North Teaching Hospital, Ragama, Sri Lanka over the past eight years, in contrast to treating several patients a week about a decade ago. Therefore, at the eve of elimination of malaria from Sri Lanka, it is likely that the infection is mostly encountered among travellers who return from endemic areas, or among the military who serve in un-cleared areas of Northern Sri Lanka. They may act as potential sources of introducing malaria as until malaria eradication is carried out. These cases highlight that change in the symptomatology, forgetfulness regarding malaria as a cause of acute febrile illness and deterioration of the competency of microscopists as a consequence of the low disease incidence, which are all likely to contribute to the delay in the diagnosis. The importance regarding awareness of new malaria treatment regimens, treatment under direct observation, prompt notification of suspected or diagnosed cases of malaria and avoiding blind use of anti-malarials are among the other responsibilities expected of all clinicians who manage patients in countries reaching malaria elimination