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Dewasurendra R, Samaranayake N, Silva H, Manamperi N, Senerath U, Senanayake S, de Silva N, Karunanayake P, Zhou G, Karunaweera N. Risk Factor Analysis of Cutaneous Leishmaniasis in Sri Lanka through a Nationwide Survey. Am J Trop Med Hyg 2024; 110:1110-1116. [PMID: 38593788 PMCID: PMC11154038 DOI: 10.4269/ajtmh.23-0623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/16/2023] [Indexed: 04/11/2024] Open
Abstract
Leishmaniasis in Sri Lanka was first reported in the early 1990s. Cutaneous leishmaniasis (CL) cases have markedly increased in recent years, demanding due attention from health authorities. The spatial distribution of CL is not homogeneous. This case-control study investigated factors that may contribute to this heterogeneous distribution through a nationwide study. Information on sociodemographic, economic, and environmental characteristics was collected from study participants (cases, n = 303; controls, n = 2,762). All individuals were followed up for 3 years, and signs of CL or associated complications were recorded. Differences in possible risk factors between cases and controls were analyzed. Individuals <18 years old, electricity supply, spending >2 hours outdoors, visiting jungles/water bodies, and living near CL patients were identified as risk factors. Household members of 1.3% of cases, 2.3% of controls residing within a perimeter of 500 m from a patient, and 0.8% of controls living beyond 2 km from a case developed CL. Thus, CL in Sri Lanka appears intertwined with living environment and host behavior. Common environmental factors may be responsible for the higher risk of CL in individuals living in close proximity to CL patients. This may at least partly explain the clustering of CL cases in selected areas of the country.
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Affiliation(s)
- Rajika Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Nilakshi Samaranayake
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Hermali Silva
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Nuwani Manamperi
- Department of Parasitology, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka
| | - Upul Senerath
- Department of Community Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Sanath Senanayake
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Nissanka de Silva
- Department of Zoology, Faculty of Applied Sciences, University of Sri Jayawardenapura, Nugegoda, Sri Lanka
| | - Panduka Karunanayake
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Guofa Zhou
- Department of Population Health and Disease Prevention, University of California, Irvine, California
| | - Nadira Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
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Deepachandi B, Weerasinghe S, Gunathileka H, Soysa P, Siriwardana Y. In vitro growth of Leishmania parasites from biopsy samples of suspected cutaneous and visceral leishmaniasis cases in Sri Lanka: An observational study. Exp Parasitol 2024; 259:108710. [PMID: 38350521 DOI: 10.1016/j.exppara.2024.108710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 12/19/2023] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
Sri Lanka reports a large focus of Leishmania donovani caused cutaneous leishmaniasis (CL). Subsequent emergence of visceral leishmaniasis (VL) was also reported recently. Expansion of the on-going disease outbreak and many complexities indicate urgent need to enhance early case detection methods. In vitro cultivation (IVC) of parasites causing visceral leishmaniasis (VL) is important for disease confirmation and to obtain sufficient quantities of parasites required in many scientific studies. IVC is carried out as a useful second line investigation for direct microscopy negative patients with CL in this setting. Along with the emergence of VL, current study was carried out to evaluate in vitro growth of local VL parasites and to identify their differences associated with in vitro growth characteristics. Routine parasitological diagnostic methods, i.e., light microscopy (LM), polymerase chain reaction (PCR) were used for confirmation of suspected cases. Lesion samples from 125 suspected CL cases and bone marrow or splenic aspirations from 125 suspected VL patients were used to inoculate IVCs. Media M199 (about 70 μl) supplemented with 15-20% of heat inactivated fetal bovine serum was used for initial culturing procedures in capillaries. Capillary cultures were monitored daily. Total of 44 different compositions/conditions were used for evaluating in vitro growth of VL causing parasite. Daily records on parasite counts, morphological appearance (size, shape, and wriggly movements) were maintained. In vitro transformation of Leishmania promastigotes to amastigotes and outcome of the attempts on recovery of live Leishmania from culture stabilates was also compared between CL and VL parasites. Proportion of cultures showing a transformation of promastigotes were 40/45 (88.9%) and 4/10 (40.0%) for CL and VL respectively. In the transformed cultures, parasites showing typical shape, size and movement patterns were less in VL (1/4, 25.0%) compared to CL (28/40, 70.0%). CL cultures showed a growth up to mass culturing level with mean duration of two weeks while it was about five weeks for VL cultures. Proportion of cultures that reached a parasite density of 1 × 106 cells/ml (proceeded to mass cultures) was significantly low in VL (4/10, 40%) as compared to CL (28/40, 70.0%). None of media compositions/conditions were successful for mass culturing of VL parasites while all of them were shown to be useful for growing CL strains. Also in vitro transformation to amastigote form and recovering of culture stabilates were not successful compared to CL. There were clear differences between in vitro growth of Leishmania parasites causing local CL and VL. Further studies are recommended for optimization of in vitro culturing of VL parasite which will be invaluable to enhance case detection in future.
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Affiliation(s)
- Bhagya Deepachandi
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, 00800, Sri Lanka; Department of Biomedical Science, Faculty of Science, NSBM Green University, Homagama, 10206, Sri Lanka
| | - Sudath Weerasinghe
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, 00800, Sri Lanka
| | - Himali Gunathileka
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, 00800, Sri Lanka
| | - Preethi Soysa
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, Colombo 00800, Sri Lanka
| | - Yamuna Siriwardana
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, 00800, Sri Lanka.
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Riyal FH, Samaranayake TN, Amarathunga P, Munidasa D, Karunaweera ND. Histological findings associated with treatment response in cutaneous leishmaniasis: a clinicopathological correlation study. Int J Dermatol 2023; 62:1237-1247. [PMID: 37723978 PMCID: PMC10516507 DOI: 10.1111/ijd.16826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 07/04/2023] [Accepted: 08/14/2023] [Indexed: 09/20/2023]
Abstract
BACKGROUND Treatment responses to cutaneous leishmaniasis (CL) observed in Sri Lanka show variability, ranging from quick healing to delayed or failed responses to routine medication. The determinants of these differences in treatment response are not well defined. This study aimed to identify predictive features of treatment response and outcome in localized CL caused by Leishmania donovani, focusing on both clinical and histopathological findings in the patients. METHODS Tissue sections (n = 103) derived from 3 mm punch biopsies of parasitologically confirmed patients were assessed. Patients were followed up weekly until complete healing of skin lesions and were reviewed at the end of 6 months and 1 year. RESULTS Healing required 7-21 weekly doses of intralesional sodium stibogluconate (IL-SSG) (mean = 12.2 ± 0.622). Twenty-nine (28.1%) patients were identified as delayed responders. None had recurred at the end of 1 year. The demographic or clinical features (age, gender, lesion type, size, location, and lesion duration) did not significantly influence the treatment response. A heavy parasite load and acanthosis were significant predictors of a delayed response to treatment (P < 0.001). Higher parasite loads were associated with inflammation of the entire dermis (P = 0.008), more intense infiltration of macrophages (p = 0.001), and epidermal atrophy (P = 0.033). Well-formed granulomas were inversely proportional to parasite loads. CONCLUSIONS Histology findings proved to be better prognostic markers than clinical features for delayed responders to treatment and will aid in targeted patient management when tissue biopsies are performed in the initial diagnosis of CL.
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Affiliation(s)
- F. Hasna Riyal
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | - Priyani Amarathunga
- Department of Pathology, Faculty of Medicine, University of Colombo, Sri Lanka
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Deepachandi B, Weerasinghe S, Soysa P, Chatterjee M, Siriwardana Y. Serological studies on rK39 negative Visceral Leishmaniasis in an endemic focus of Leishmania donovani induced Cutaneous Leishmaniasis. Diagn Microbiol Infect Dis 2023; 105:115873. [PMID: 36543026 DOI: 10.1016/j.diagmicrobio.2022.115873] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022]
Abstract
Sri Lanka reports a focus of L. donovani induced cutaneous leishmaniasis (CL). Our more recent parasite and clinical studies and historical evidence point towards long term existence of Leishmania in the country, indicating a possible evolution leading to antigenic heterogenicity as well. In-house enzyme-linked immunosorbent assay (ELISA) that was developed during phase 1 study indicated >80% sero-positivity in local CL, while visceral leishmaniasis (VL) remained very rare with majority being negative when tested with rK39 assay. A novel serological tool was developed and sero-positivity of VL was assessed for the first time. The assay showed 100.0% sensitivity and 98.3% specificity for detection of VL. Samples were showed less positivity with established direct agglutination test (DAT) and rK39 strip test. The assay was less expensive than that of established rapid diagnostic tests (RDTs), culture and PCR assays. This assay may be useful in diagnosing clinical VL infections, detection of light microscopy (LM) negative patients, tracking post treatment stages, field screening of asymptomatic cases and in further serological studies.
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Affiliation(s)
- Bhagya Deepachandi
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Sudath Weerasinghe
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Preethi Soysa
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Mitali Chatterjee
- Department of Pharmacology, Institute of Postgraduate Medical Education and Research, Kolkata, West Bengal, India
| | - Yamuna Siriwardana
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
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Deepachandi B, Ejazi SA, Bhattacharyya A, Ali N, Soysa P, Siriwardana Y. Measuring the sero-prevalence of Leishmania donovani induced cutaneous leishmaniasis: A method comparison study. Parasitol Int 2023; 92:102660. [PMID: 36038060 DOI: 10.1016/j.parint.2022.102660] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 07/30/2022] [Accepted: 08/23/2022] [Indexed: 10/15/2022]
Abstract
An in-house enzyme-linked immunosorbent assay (ELISA) based on crude antigen of Leishmania reported a high sero-prevalence (82.0%) in Leishmania donovani induced cutaneous leishmaniasis (CL) in Sri Lanka. ELISA was further compared with established serological tools to identify a suitable point of care diagnostic tool. Sero-prevalence of 100 CL samples were analyzed using in-house ELISA, Indian dipstick test and rK39 strip test. Results obtained were further compared with direct agglutination test (DAT) for 40 CL. Test performance was evaluated using Kappa index value. Clinico-epidemiological characteristics of patients were analyzed using SPSSv25.0. Cost analysis of tests was carried out. ELISA showed a high sero-positivity of 81.0% (n = 81/100) while DAT (57.5%,n = 23/40), Indian dipstick test (22.0%,n = 22/100) and rK39 test (15.0%,n = 15/100) showed a comparatively less sero-positivity. According to Kappa index values, there were no perfect agreement between tests. Among ELISA positive patients (n = 81/100), DAT, Indian dipstick test and rK39 demonstrated sero-positivity rates of 61.3% (n = 19/31), 25.9% (n = 21/81) and 16.0% (n = 13/81) respectively. Among ELISA negative patients (n = 19/100), three assays demonstrated sero-positivity rates of 44.4% (n = 4/9), 5.3% (n = 1/9) and 10.5% (n = 2/19) respectively. DAT can be used as an alternative test when ELISA is not available or negative. Clinico-epidemiological profiles of patients that showed sero-positivity by each assay were different. Cost per patient was approximately 5.5 USD for DAT and 3.0 USD for each other tests. Established serological tests demonstrated different and relatively lower detection rates. Species, strain and antigen heterogeneity, inconsistency in amount of used antigens, sera, antibody expression patterns and testing methodologies could be responsible. This study highlighted the importance of designing an in-house serological assay based on local parasite.
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Affiliation(s)
- Bhagya Deepachandi
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 00800, Sri Lanka
| | - Sarfaraz A Ejazi
- CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal 700032, India
| | | | - Nahid Ali
- CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal 700032, India
| | - Preethi Soysa
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, Colombo 00800, Sri Lanka
| | - Yamuna Siriwardana
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 00800, Sri Lanka.
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Nuwangi H, Weerakoon KG, Agampodi TC, Price HP, Dikomitis L, Agampodi SB. Rewriting the history of leishmaniasis in Sri Lanka: An untold story since 1904. PLoS Negl Trop Dis 2022; 16:e0010918. [PMID: 36480521 PMCID: PMC9731464 DOI: 10.1371/journal.pntd.0010918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Leishmaniasis is widely considered a disease that emerged in Sri Lanka in the 1990s. However, a comprehensive case report from 1904 suggests that the presence of Leishmaniasis was well demonstrated in Sri Lanka long before that. The Annual Administration Reports of Ceylon/Sri Lanka from 1895 to 1970 and the Ceylon Blue Book from 1821 to 1937 are official historical documents that provide an annual performance, progress, goals achieved, and finances of Sri Lanka during that time. Both these documents are available in the National Archives. The Ceylon Administrative Report of 1904 reports a full record of observation of Leishman-Donovan bodies in Sri Lanka for the first time. These reports contain a total of 33,438 cases of leishmaniasis in the years 1928 to 1938, 1953, 1956, 1957, 1959, 1960, and 1961 to 1962. Up to 1938, the term "cutaneous leishmaniasis" was used, and after 1938, the term "leishmaniasis" was used in these reports. "Kala-azar" was also mentioned in 11 administrative reports between 1900 and 1947. In 1947, an extensive vector study has been carried out where they reported kala-azar cases. This well-documented government health information clearly shows that the history of leishmaniasis is almost the same as the global history in which the first case with Leishman-Donovan bodies were reported in 1903.
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Affiliation(s)
- Hasara Nuwangi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
- * E-mail:
| | - Kosala Gayan Weerakoon
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Thilini Chanchala Agampodi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
| | - Helen Philippa Price
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
| | - Lisa Dikomitis
- Kent and Medway Medical School, University of Kent and Canterbury Christ Church University, Canterbury, United Kingdom
| | - Suneth Buddhika Agampodi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Sri Lanka
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Lypaczewski P, Matlashewski G. Leishmania donovani hybridisation and introgression in nature: a comparative genomic investigation. THE LANCET MICROBE 2021; 2:e250-e258. [DOI: 10.1016/s2666-5247(21)00028-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 01/19/2021] [Accepted: 01/27/2021] [Indexed: 01/17/2023] Open
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First Evidence from Sri Lanka for Subphenotypic Diversity within L. donovani-Induced Classical Cutaneous Leishmaniasis. BIOMED RESEARCH INTERNATIONAL 2021; 2021:3537968. [PMID: 33575327 PMCID: PMC7861938 DOI: 10.1155/2021/3537968] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 01/10/2021] [Accepted: 01/19/2021] [Indexed: 11/22/2022]
Abstract
Sri Lanka reports a large focus of Leishmania donovani-induced cutaneous leishmaniasis (CL) with CL as the main clinical entity. Two independent, long existed, and clinicoepidemiologically different transmission foci in the northern region (NR) and southern region (SR) were recently reported. Current project is an extension to this previous study. Clinical diversity within a profile of classical cutaneous leishmaniasis (CCL) in a focus of L. donovani-induced CL is described for the first time. Patients with laboratory confirmed CCL (n = 550) from NF and SF were evaluated. Lesions in both foci were found to have all classical developmental stages (small and large nodules, ulcerating nodules, and ulcers) and other identified changes (multiplication, ulceration, and enlargement). Main difference was in the proportions of lesions progressing in to each different stages, proportions of lesion undergoing the main changes, and in timing of these changes during the course of a lesion. Northern focus reported a smaller proportion of lesions showing enlargement and ulceration, and a longer period of time was also required for these changes when compared to same in southern focus. In northern focus, most lesions remained small and nonulcerating and showed a higher tendency to multiply while most lesions reported in southern focus enlarged and ulcerated rapidly and remained single. Current study also evidenced a wider spectrum in the rate and pattern of progression of a skin lesion and high individual variation which could mask these region-based differences. Parasitic, vector-related, or a host etiology is suggested. Slow progressing nonulcerating infections in North may be the result of a well-adopted parasite strain that coevolved with its host for a long period while inducing only a minimal host response. This could be one among many reasons for previously observed silent expansion in northern focus while southern focus remained more confined and stable over time. Small nonprogressive, nondisturbing lesions can play a major role as silent parasite reservoirs in a community. In addition, the laboratory detection rate declined significantly when lesions multiplied and enlarged indicating the need for early laboratory confirmation. Usefulness of identified features in clinical screening and management needs to be considered.
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First Serological Study Revealing High Humoral Response and Evidence for Antigenic Heterogeneity in Leishmania donovani Induced CL in Sri Lanka. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5271657. [PMID: 33145352 PMCID: PMC7599090 DOI: 10.1155/2020/5271657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/15/2020] [Indexed: 01/24/2023]
Abstract
Posing a threat to the ongoing leishmaniasis elimination efforts in the Indian subcontinent, L. donovani-induced cutaneous leishmaniasis (CL) has been recently reported in many countries. Sri Lanka reports a large focus of human cutaneous leishmaniasis (CL) caused by Leishmania donovani, a usually visceralizing parasite. Enhanced case detection, early treatment, and in-depth understanding of sequalae are required to contain the spread of disease. Visceralizing potential of dermotropic strains has not been fully ruled out. Sri Lankan strains have shown a poor response to established serological assays. The present concern was to develop an in-house serological assay and to determine the seroprevalence of CL for identifying visceralizing potential and its usefulness in enhancing case detection. Crude cell lysate of dermotropic L. donovani promastigotes-based indirect enzyme-linked immunosorbent assay (ELISA) was previously optimized. Assay was evaluated using sera from 200 CL patients, 50 endemic and 50 nonendemic healthy controls, 50 patients with other skin diseases, and 50 patients with other systemic diseases. Seroprevalence and clinicoepidemiological associations were analyzed. Assay was compared with light microscopy (LM) and in vitro culturing (IVC). Cost comparison was carried out. Seroprevalence of CL was 82.0%. The assay had 99.5% specificity, and all healthy controls were negative at 0.189 cut-off. Positive and negative predictive values were 99.4% and 84.7%, respectively. Positivity obtained in ELISA was comparable to LM and higher than that of IVC. Cost per patient was 3.0 USD for both ELISA and LM and 6.0 USD for IVC. Infections occurring in all age groups and both genders demonstrated >75.0% of seropositivity. Patients had lesions with different durations/types/sizes showed >70.0% of seropositivity. Study identified a high seroprevalence of L. donovani-induced CL for the first time, indicating potential for visceralization or transient serological response. This can be used as a second line test in LM-negative CL cases to enhance clinical case detection. Further studies are warranted to examine in-depth correlations, antigen profiles, comparison with other established serological tools, and usefulness in the detection of asymptomatic cases. (National patent LK/P/1/19697).
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Prevalidation of an ELISA for Detection of a New Clinical Entity: Leishmania donovani-Induced Cutaneous Leishmaniasis. Int J Anal Chem 2020; 2020:9289651. [PMID: 32733568 PMCID: PMC7378632 DOI: 10.1155/2020/9289651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/29/2020] [Indexed: 02/08/2023] Open
Abstract
Human leishmaniasis which is considered a neglected tropical parasitic disease presents in three main clinical forms (i.e., cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL)) that are mainly determined by its causative species. Leishmania donovani, the most virulent and visceralizing parasite, is increasingly reported to cause CL in many countries in the world. Although CL is generally not considered to evoke a humoral immune response except for a nonrobust and a variable response in minority of cases, VL is associated with a clear strong humoral response. However, humoral response in L. donovani-induced CL has not been well evaluated before. A suitable serology-based assay is an essential primary step in such a study. An indirect enzyme-linked immunosorbent assay (ELISA) based on Leishmania promastigote crude antigen (Ag) was designed and optimized in order to utilize in further serological studies on this new clinical entity. Optimization included quantification of crude Ag, checkerboard titration method for determination of optimal concentrations for coating Ag, human sera and secondary antibody (Ab) with suitable coating buffer, blocking buffer, and incubating temperatures. The selected coating buffer was 0.02 M phosphate buffer, pH 6.8, and the blocking buffer was 2% fetal bovine serum with 0.01 M phosphate-buffered saline. At least 1 μg of crude Ag was required for coating the ELISA plate, while 1 : 1000 serum was used as primary Ab. The optimized concentration of secondary Ab was 1 : 64000 which might be altered according to manufacturer recommendations. The assay specificity was pre-evaluated using sera (n = 20 from each category) from confirmed CL patients and controls (other skin diseases which mimic CL, other systemic diseases that mimic VL, nonendemic healthy controls, and endemic healthy controls). This procedure described an optimization procedure of an ELISA technique for detection of anti-Leishmania antibodies in patients with L. donovani caused CL.
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A Comprehensive Review of Cutaneous Leishmaniasis in Sri Lanka and Identification of Existing Knowledge Gaps. Acta Parasitol 2020; 65:300-309. [PMID: 32052240 PMCID: PMC7223001 DOI: 10.2478/s11686-020-00174-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/24/2020] [Indexed: 11/28/2022]
Abstract
Purpose Sri Lanka is endemic to cutaneous leishmaniasis and reported as the latest focus of leishmaniasis in the Asian subcontinent. Annually, the number of leishmaniasis cases is increasing; therefore, more efficient diagnostic tools, treatment methods and effective prevention measures are indispensable. For this reason, many studies were conducted regarding leishmaniasis infections in Sri Lanka; however, some areas need more attention. Thus, in this review, we comprehensively discussed the studies on leishmaniasis carried out in Sri Lanka. Methods Published articles on leishmaniasis in Sri Lanka were searched on PubMed, Google Scholar and ResearchGate databases. Inclusion criteria for the articles were based on keyword searches including ‘Leishmaniasis in Sri Lanka’, ‘Leishmaniasis vector in Sri Lanka’, ‘Sandfly species in Sri Lanka’, ‘Leishmaniasis epidemiology in Sri Lanka’ which are publicly accessible as of 15th July 2019. Results In this study, we evaluated and summarized the leishmaniasis reports in Sri Lanka and mainly focused on clinical presentation of leishmaniasis infection, genetic characteristics of Leishmania donovani Sri Lankan strain, geographical distribution and associated environmental factors, immunological aspects of the infection, vector, reservoir host, risk factors, diagnosis and treatment, and prevention and control. Furthermore, we identified the areas where further research is needed to fill the essential knowledge gaps. Conclusions Leishmaniasis has become a critically important parasitic infection in Sri Lanka, whereas the significant clinical form is cutaneous leishmaniasis. Prevalence of the leishmaniasis infections is reported from all the districts of the country. Therefore, more studies are essential to be carried out to fill the existing knowledge gaps emphasized in this review.
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