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Naing C, Whittaker MA, Tung WS, Aung H, Mak JW. Prevalence of zoonotic (brugian) filariasis in Asia: A proportional meta-analysis. Acta Trop 2024; 249:107049. [PMID: 37866729 DOI: 10.1016/j.actatropica.2023.107049] [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: 08/28/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 10/24/2023]
Abstract
Lymphatic filariasis is a public health problem and targeted for global elimination. WHO recommends mass drug administration to interrupt transmission of the parasites involved. There are concerns that transmission interruption may be difficult in areas of zoonotic filarial infections. This study aimed to estimate the pooled prevalence of zoonotic brugian filariasis, and to compare the pooled prevalence of brugian filariasis in human and animal populations in the same area based on available studies. A comprehensive literature search was conducted in health-related electronic databases (PubMed, Ovid MEDLINE, Index Medicus, google scholar). A random-effect meta-analysis of the pooled overall prevalence of filariasis in animal populations was conducted. Sixteen studies from four different Asian countries were identified. Studies were conducted most frequently in Thailand (n = 7), followed by Malaysia (n = 5), India (n = 3), and Sri Lanka (n = 1). Regardless of animal group, the pooled overall prevalence of animal Brugia infections was 13% (95%CI: 7-21%, I2:98%, 16 studies). On stratification, the pooled overall prevalence in the animal population was 19% (95%CI: 1-50%, I2: 99%, 3 studies) in India, 8% (95%CI: 2-7%, I2: 97%, 5 studies) in Malaysia, and 13% (95%CI: 7-20%, I2: 94%, 7 studies) in Thailand. The prevalence in the animal population was 17% (95%CI: 13-21%, 1 study) in Sri Lanka. The pooled overall prevalence of Brugia malayi was 13% (95%CI: 7-21%, I2:98%, 12 studies), while for Brugia pahangi this was 12% (95%CI: 7-19%, I2:86%, 7 studies). Regardless of animal group, geographic area, or diagnostic test, the prevalence of B. malayi was consistently high. On stratification by animal category, the pooled overall prevalence was 10% (95%CI: 6-14%, I2:92%, 13 studies) in cats, 12% (95%CI: 2-28%, I2: 99%, 6 studies) in dogs, and 55% (95%CI: 47-63%, 1 study) in leaf-eating monkeys. The findings show the extent of zoonotic Brugiainfections in domestic cats and dogs, suggesting that these animals are potential reservoirs for human brugian filariasis in the study countries. To substantiate this with more accuracy, future well designed whole genomic sequencing of individual mf collected from humans and B. malayi infected animals in the same area are needed.
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Affiliation(s)
- Cho Naing
- Division of Tropical Health and Medicine, James Cook University, Queensland, Australia.
| | - Maxine A Whittaker
- Division of Tropical Health and Medicine, James Cook University, Queensland, Australia.
| | - Wong Siew Tung
- School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Htar Aung
- Institute of Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia
| | - Joon Wah Mak
- Institute of Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia
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Atapattu U, Koehler AV, Huggins LG, Wiethoelter A, Traub RJ, Colella V. Dogs are reservoir hosts of the zoonotic Dirofilaria sp. 'hongkongensis' and potentially of Brugia sp. Sri Lanka genotype in Sri Lanka. One Health 2023; 17:100625. [PMID: 38024272 PMCID: PMC10665175 DOI: 10.1016/j.onehlt.2023.100625] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/25/2023] [Accepted: 08/29/2023] [Indexed: 12/01/2023] Open
Abstract
In 2016, the World Health Organization declared Sri Lanka as having successfully eliminated lymphatic filariasis as a public health concern. However, in recent decades, several infections with subperiodic filarial species suggestive of zoonotic infections have been recorded across the country. The arthropod-borne filarioids Dirofilaria repens, Brugia malayi, Brugia ceylonensis, and Acanthocheilonema reconditum are historically known to be endemic in dogs in Sri Lanka. Despite this, limited information on the prevalence, diversity, and predictors of filarial infections in dogs in the country has resulted in suboptimal control and prevention of these parasites, some of which are known to be zoonotic. To address this, whole blood and metadata were collected and analysed from 423 pet dogs across three geo-climatic zones within Sri Lanka. Blood samples were screened using the Modified Knott's Test (MKT) and PCR followed by Sanger sequencing. Multivariable logistic regression models were used to assess predictors for canine filarial infections. Dirofilaria sp. 'hongkongensis' (Dirofilaria sp. HK) and Brugia sp. Sri Lanka (SL) genotype were identified infecting dogs. The overall prevalence of filarial infection in pet dogs by PCR was 36.9% (95% CI 32.3-41.7%, n = 156), compared to 18.8% (95% CI 15.2-22.9%, n = 79) detected using the MKT. >80% of filarial-positive dogs were infected by Dirofilaria sp. HK, while the remaining dogs were infected by Brugia sp. SL genotype. Increasing age (p < 0.001) and residing in the low-country wet zone (p < 0.001), which includes regions that were endemic for human filariasis in Sri Lanka, were associated with filarial infections in dogs. No clear pathognomonic signs for filarial infection were identified, indicating that dogs act as reservoirs for these potentially zoonotic pathogens. Given the morphological similarity of Dirofilaria HK and Brugia sp. SL microfilariae with those of D. repens and B. malayi, respectively, it is likely that these species have been misidentified in the past. Prevention and control measures of these potentially zoonotic canine filarial infections are highly advocated to safeguard both canine and human health.
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Affiliation(s)
- Ushani Atapattu
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
| | - Anson V. Koehler
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
| | - Lucas G. Huggins
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
| | - Anke Wiethoelter
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
| | - Rebecca J. Traub
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
| | - Vito Colella
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, VIC 3010, Australia
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Chandrasena NTGA, Gunaratna IE, Ediriweera D, de Silva NR. Lymphatic filariases and soil-transmitted helminthiases in Sri Lanka: the challenge of eliminating residual pockets of transmission. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220280. [PMID: 37598710 PMCID: PMC10440162 DOI: 10.1098/rstb.2022.0280] [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: 10/25/2022] [Accepted: 04/06/2023] [Indexed: 08/22/2023] Open
Abstract
Sri Lanka has successfully met the challenge of controlling both lymphatic filariasis (LF) and soil-transmitted helminthiases (STH) as public health problems. The primary public health strategy for combatting both conditions has been preventive chemotherapy. The national programme for the elimination of LF implemented five annual rounds of mass chemotherapy in the endemic districts from 2002 to 2006 using a combination of diethylcarbamazine and albendazole. The overall microfilaria rate declined from 0.21% in 2001 before the mass chemotherapy, to 0.06% in 2016, at declaration of elimination of LF as a public health problem by the World Health Organization. Currently Sri Lanka is in the phase of post-validation surveillance. Achieving control of STH has been more difficult. Mass deworming programmes have been implemented for nearly a century, and national-level surveys reported prevalence rates declining from 6.9% in 2003 to 1% in 2017. However, neither of these infections has been completely eliminated. A situation analysis indicates continued transmission of both among high-risk communities. This paper explores the reasons for persistence of transmission of both LF and STH in residual pockets and the measures that are required to achieve long-term control, or perhaps even interrupt transmission in Sri Lanka. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
| | - I. E. Gunaratna
- Anti-Filariasis Campaign, Ministry of Health, Elvitigala Mawatha, Colombo 00500, Sri Lanka
| | - Dileepa Ediriweera
- Health Data Science Unit, University of Kelaniya, Talagolla Road, Ragama 11010, Sri Lanka
| | - N. R. de Silva
- Department of Parasitology, Faculty of Medicine, University of Kelaniya, Talagolla Road, Ragama 11010, Sri Lanka
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Bhoj P, Togre N, Khatri V, Goswami K. Harnessing Immune Evasion Strategy of Lymphatic Filariae: A Therapeutic Approach against Inflammatory and Infective Pathology. Vaccines (Basel) 2022; 10:vaccines10081235. [PMID: 36016123 PMCID: PMC9415972 DOI: 10.3390/vaccines10081235] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 02/04/2023] Open
Abstract
Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-term survival in a host. These strategies include regulation of pattern recognition receptors, mimicry with host glycans and immune molecules, manipulation of innate and adaptive immune cells, induction of apoptosis in effector immune cells, and neutralization of free radicals. This creates an anti-inflammatory and immunoregulatory milieu in the host: a modified Th2 immune response. Therefore, targeting filarial immunomodulators and manipulating the filariae-driven immune system against the filariae can be a potential therapeutic and prophylactic strategy. Filariae-derived immunosuppression can also be exploited to treat other inflammatory diseases and immunopathologic states of parasitic diseases, such as cerebral malaria, and to prevent leishmaniasis. This paper reviews immunomodulatory mechanisms acquired by these filariae for their own survival and their potential application in the development of novel therapeutic approaches against parasitic and inflammatory diseases. Insight into the intricate network of host immune-parasite interactions would aid in the development of effective immune-therapeutic options for both infectious and immune-pathological diseases.
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Affiliation(s)
| | - Namdev Togre
- Department of Biological Sciences, University of Texas, El Paso, TX 79968, USA
- Correspondence: (N.T.); (K.G.)
| | | | - Kalyan Goswami
- All India Institute of Medical Sciences, Saguna, Kalyani 741245, India
- Correspondence: (N.T.); (K.G.)
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Canine filaria species in selected lymphatic filariasis endemic and non-endemic areas in Sri Lanka. Parasitol Res 2022; 121:2187-2191. [PMID: 35614145 DOI: 10.1007/s00436-022-07555-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/16/2022] [Indexed: 10/18/2022]
Abstract
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.
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Rogers MJ, McManus DP, Muhi S, Gordon CA. Membrane Technology for Rapid Point-of-Care Diagnostics for Parasitic Neglected Tropical Diseases. Clin Microbiol Rev 2021; 34:e0032920. [PMID: 34378956 PMCID: PMC8404699 DOI: 10.1128/cmr.00329-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Parasitic neglected tropical diseases (NTDs) affect over one billion people worldwide, with individuals from communities in low-socioeconomic areas being most at risk and suffering the most. Disease management programs are hindered by the lack of infrastructure and resources for clinical sample collection, storage, and transport and a dearth of sensitive diagnostic methods that are inexpensive as well as accurate. Many diagnostic tests and tools have been developed for the parasitic NTDs, but the collection and storage of clinical samples for molecular and immunological diagnosis can be expensive due to storage, transport, and reagent costs, making these procedures untenable in most areas of endemicity. The application of membrane technology, which involves the use of specific membranes for either sample collection and storage or diagnostic procedures, can streamline this process, allowing for long-term sample storage at room temperature. Membrane technology can be used in serology-based diagnostic assays and for nucleic acid purification prior to molecular analysis. This facilitates the development of relatively simple and rapid procedures, although some of these methods, mainly due to costs, lack accessibility in low-socioeconomic regions of endemicity. New immunological procedures and nucleic acid storage, purification, and diagnostics protocols that are simple, rapid, accurate, and cost-effective must be developed as countries progress control efforts toward the elimination of the parasitic NTDs.
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Affiliation(s)
- Madeleine J. Rogers
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Donald P. McManus
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Stephen Muhi
- Victorian Infectious Diseases Service, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Catherine A. Gordon
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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Molecular Characterization of a Reemergent Brugia malayi Parasite in Sri Lanka, Suggestive of a Novel Strain. BIOMED RESEARCH INTERNATIONAL 2021; 2021:9926101. [PMID: 34414239 PMCID: PMC8370822 DOI: 10.1155/2021/9926101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 07/28/2021] [Indexed: 12/03/2022]
Abstract
Sri Lanka achieved elimination status for lymphatic filariasis in 2016; still, the disease remains a potential public health issue. The present study is aimed at identifying a subperiodic Brugia sp. parasite which has reemerged in Sri Lanka after four decades via molecular-based analysis. Polymerase chain reaction performed with pan-filarial primers specific for the internal transcribed spacer region-2 (ITS-2) of the rDNA of Brugia filarial parasites isolated from human, canine, and feline blood samples yielded a 615 bp band establishing the species identity as Brugia malayi. Comparison of the ITS2 sequences of the reemerged B. malayi isolates with GenBank sequences revealed a higher sequence homology with B. pahangi than B. malayi with similar phylogenetic evidence. However, the mean interspecies Kimura-2-parameter pairwise divergence between the generated Brugia sequences with B. malayi and B. pahangi was less than 3%. During the analysis of parsimony sites of the new ITS2 sequences, substitutions at A36T, A296G, T373A, and G482A made the sequences different from both B. pahangi and B. malayi suggesting the possibility of a new genetic variant or a hybrid strain of B. malayi and B. pahangi. Mosquito dissections and xenomonitoring identified M. uniformis and M. annulifera as vectors of this novel strain of B. malayi circulating among cats, dogs, and humans in Sri Lanka.
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Colella V, Nguyen VL, Tan DY, Lu N, Fang F, Zhijuan Y, Wang J, Liu X, Chen X, Dong J, Nurcahyo W, Hadi UK, Venturina V, Tong KBY, Tsai YL, Taweethavonsawat P, Tiwananthagorn S, Le TQ, Bui KL, Watanabe M, Rani PAMA, Annoscia G, Beugnet F, Otranto D, Halos L. Zoonotic Vectorborne Pathogens and Ectoparasites of Dogs and Cats in Eastern and Southeast Asia. Emerg Infect Dis 2021; 26:1221-1233. [PMID: 32441628 PMCID: PMC7258489 DOI: 10.3201/eid2606.191832] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To provide data that can be used to inform treatment and prevention strategies for zoonotic pathogens in animal and human populations, we assessed the occurrence of zoonotic pathogens and their vectors on 2,381 client-owned dogs and cats living in metropolitan areas of 8 countries in eastern and Southeast Asia during 2017–2018. Overall exposure to ectoparasites was 42.4% in dogs and 31.3% in cats. Our data cover a wide geographic distribution of several pathogens, including Leishmania infantum and zoonotic species of filariae, and of animals infested with arthropods known to be vectors of zoonotic pathogens. Because dogs and cats share a common environment with humans, they are likely to be key reservoirs of pathogens that infect persons in the same environment. These results will help epidemiologists and policy makers provide tailored recommendations for future surveillance and prevention strategies.
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Evans CC, Burkman EJ, Dzimianski MT, Garner B, Moorhead AR. The Course of Brugia malayi Microfilaremia in Experimentally Infected Cats. Vector Borne Zoonotic Dis 2021; 21:586-592. [PMID: 34129397 DOI: 10.1089/vbz.2020.2761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
As one of the causative agents of lymphatic filariasis in humans, Brugia malayi has been established as the laboratory model of choice for studying this infection owing to its viability in small animal hosts, with the domestic cat being significant among these. The usefulness of individual feline infections is highly dependent on the levels of circulating microfilariae in the blood; thus, characterizing the course of microfilaremia benefits our understanding of this model. In B. malayi-endemic regions, cats are also known reservoirs of infection, and describing microfilaremia in a controlled setting may improve transmission modeling. We followed the course of B. malayi infection in 10 experimentally infected cats from inoculation to ultimate resolution. Seven cats developed patency, with a peak microfilaria concentration of 6525/mL. In addition, to identify cellular responses with potential value as predictors of patency, we measured the peripheral blood leukocyte counts during the first 8 months of infection and tested for correlations with lifelong microfilaria production. No strong relationships were observed, though cell values did appear to shift with the maturation phases of the parasite. The data we present reflect the course of microfilaremia in an important laboratory model under controlled conditions.
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Affiliation(s)
- Christopher C Evans
- Department of Infectious Diseases and College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Erica J Burkman
- Department of Infectious Diseases and College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Michael T Dzimianski
- Department of Infectious Diseases and College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Bridget Garner
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Andrew R Moorhead
- Department of Infectious Diseases and College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
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Assessing the Filariasis Causing Parasites in Adult Mosquitoes and the Vector Mosquito Larval Breeding in Selected Medical Officer of Health Areas in Gampaha District, Sri Lanka. J Trop Med 2021; 2021:6643226. [PMID: 33927771 PMCID: PMC8053054 DOI: 10.1155/2021/6643226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 11/18/2022] Open
Abstract
The present study was conducted to determine the prevalence of filariasis causing parasites in adult mosquitoes and vector mosquito larval breeding in four Medical Officer of Health (MOH) areas in Gampaha district, Sri Lanka. Adult female mosquitoes at their resting places were collected using a prokopack aspirator operated twice a day from 7.00 am to 8.00 am and 8.00 pm to 9 pm in predetermined dates. Microfilarial worms in dissected mosquitoes were morphologically identified. Nine species of mosquitoes, namely, Culex quinquefasciatus, Cx. pipiens, Cx. fuscocephala, Cx. gelidus, Armigeres subalbatus, Mansonia uniformis, Ma. annulifera, Aedes aegypti, and Ae. Albopictus, were captured. A total of 1194 mosquito larvae were collected that belonged into three genera, namely, Culex (62.73%), Armigeres (25.62%), and Mansonia (11.64%), from blocked drains, polluted drains, blocked canals, large polluted water bodies, stagnant water bodies, marsh lands, rice field mudflats, and concrete pits. Large polluted water bodies (Shannon-Wiener diversity index/H' = 1.5591) were the most diversed habitat type. In breeding water, average pH mainly lied in between 6 and 8 and average dissolved oxygen ranged from 3 to 7 mg/L. Cx. quinquefasciatus and Armigeres subalbatus adult female mosquitoes captured from Kelaniya MOH area were positive for microfilariae and were identified as Wuchereria bancrofti and Dirofilaria repens, respectively. This study concludes possible lymphatic filariasis situation is in extremely very low level persistent (0.06%) where transmission cannot be sustained and is restricted only to isolated pockets in the study area. The zoonotic strains of filariasis causing subcutaneous dirofilariasis in humans by Dirofilaria repens is continuing to survive due to the presence of stray dogs that serve as reservoir hosts.
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Bizhani N, Hashemi Hafshejani S, Mohammadi N, Rezaei M, Rokni MB. Lymphatic filariasis in Asia: a systematic review and meta-analysis. Parasitol Res 2021; 120:411-422. [PMID: 33415391 PMCID: PMC7790732 DOI: 10.1007/s00436-020-06991-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/25/2020] [Indexed: 12/02/2022]
Abstract
Lymphatic filariasis (LF) is an important neglected parasitic disease according to the World Health Organization. In this study, we aimed to determine the prevalence of human LF in Asia using a systematic review and meta-analysis approach. Records from 1990 to 2018 in reputable databases including PubMed, Science Direct, Embase, and Cochrane Library were searched using a panel of related keywords. All 48 countries of Asia were searched one by one in combination with the keywords. In all, 41,742 cases identified in this study were included in the analysis. According to our findings, the pooled prevalence of LF in Asia was estimated at 3% (95% CI: [1.7, 5.2]). There was no major trend in the cumulative prevalence of LF over time. Some countries in Asia including China, Japan, Vietnam, and South Korea succeeded in eliminating LF as a public health problem, but others still need to monitor the disease. Based on the initiative of the WHO starting in 2000, some countries in Asia succeeded in eliminating LF as a public health problem. Other countries have taken steps to eliminate the disease with variable degrees of success. These efforts might be affected by issues such as climate change.
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Affiliation(s)
- Negar Bizhani
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeideh Hashemi Hafshejani
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Neda Mohammadi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Rezaei
- Department of Forestry and Landscape Architecture, Konkuk University, Seoul, Republic of Korea
| | - Mohammad Bagher Rokni
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Das NC, Patra R, Gupta PSS, Ghosh P, Bhattacharya M, Rana MK, Mukherjee S. Designing of a novel multi-epitope peptide based vaccine against Brugia malayi: An in silico approach. INFECTION GENETICS AND EVOLUTION 2020; 87:104633. [PMID: 33181335 DOI: 10.1016/j.meegid.2020.104633] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/18/2020] [Accepted: 11/06/2020] [Indexed: 01/19/2023]
Abstract
In spite of the tremendous efforts of the World Health Organization, scientific and medical community to eradicate lymphatic filariasis (LF) within 2020, the disease is still taking a huge toll on mankind throughout the globe. The current therapeutic strategies and solution measures against this alarming condition are suffering from a number of limitations such as inadequate effectiveness of the drugs against the adult-stage parasites, low bioavailability, and emergence of resistance. Considering this situation, development of the new therapeutics are urgently needed to combat human LF, especially targeting the adult filarial nematodes. Brugia malayi, the causative parasite for the human brugian filariasis majorly found in the countries of the South-Asia. In this study, we have designed a vaccine candidate using B-cell and T-cell epitopes derived from the aspartic protease of B. malayi (BmASP-1) and found to display significant humoral and cell mediated immune responses using in-silico approaches. Protein-protein docking between the human Toll-like receptor 4 (TLR4) and the vaccine candidate helped us to predict the way of inductive signaling that leads to immune-response. Molecular dynamics (MD) simulation studies further confirmed the proper docking between the TLR4 and vaccine candidate. Moreover, in-silico cloning of the vaccine element within the expression vector was found useful to optimize the restriction sites as well as to determine the primer location. Taken together, the in-silico vaccine candidate depicted in this study promises could be a useful therapeutic option for treating LF and experimental validation of this study is expected to strengthen the candidature of the said vaccine in the future.
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Affiliation(s)
- Nabarun Chandra Das
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol 713 340, West Bengal, India
| | - Ritwik Patra
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol 713 340, West Bengal, India
| | - Parth Sarthi Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Berhampur 760 010, Odisha, India
| | - Pratik Ghosh
- Department of Zoology, Vidyasagar University, Midnapore 721102, West Bengal, India
| | - Manojit Bhattacharya
- Department of Zoology, Fakir Mohan University, Vyasa Vihar, Balasore 756020, Odisha, India.
| | - Malay Kumar Rana
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Berhampur 760 010, Odisha, India
| | - Suprabhat Mukherjee
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol 713 340, West Bengal, India.
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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. BIOMED RESEARCH INTERNATIONAL 2020; 2020:8732473. [PMID: 33083488 PMCID: PMC7556092 DOI: 10.1155/2020/8732473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/08/2020] [Accepted: 09/17/2020] [Indexed: 01/09/2023]
Abstract
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 Bacillaceae family (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.
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Breeding Habitat Distribution of Medically Important Mosquitoes in Kurunegala, Gampaha, Kegalle, and Kandy Districts of Sri Lanka and Potential Risk for Disease Transmission: A Cross-Sectional Study. J Trop Med 2020; 2020:7915035. [PMID: 32934657 PMCID: PMC7484687 DOI: 10.1155/2020/7915035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 08/20/2020] [Indexed: 11/29/2022] Open
Abstract
Some arbovirus infections, especially dengue, have increased rapidly over the last few decades in Sri Lanka. Prevalence and distribution of different mosquito species have been limitedly documented, which remains grossly inadequate in providing evidence for potential health risks. In this study, the diversity and species composition of mosquitoes in four selected districts in Sri Lanka (Kurunegala, Gampaha, Kegalle, and Kandy) were investigated. Entomological surveys were conducted from a total of 160 temporary and permanent mosquito breeding habitats identified in the study area from June 2017 to October 2018. Mosquito immature stages were sampled using standard dipping, siphoning, or pipetting methods and identified up to the species level. Percentage relative abundance and habitat characteristics such as species richness, dominance, and Shannon–Weiner diversity were calculated for each surveyed habitat type. Associations between co-occurring species were estimated by Hulbert's coefficient of interspecific association (C8). A total of 4663 mosquito larvae belonging to seven genera and fifteen species of mosquitoes were collected. The relative distribution of mosquito species differed significantly among the four studied districts (X2 = 143.248; df = 33; P < 0.001). According to Kruskal–Wallis statistics (P < 0.05 at 95% of significance), all diversity indices for immature stages of medically important mosquitoes varied significantly across different breeding sites. Paddy fields had the significantly highest species richness of 4.0 ± 2.82. The coefficients of interspecific association among all the recorded medically important vector mosquitoes were found negative during the present study. The findings of the current study would be useful to identify the entomological potential for disease transmission and facilitate the implementation of appropriate vector control interventions. This would ultimately provide an avenue to improve the personal skills of health staff rather than limiting their knowledge to specified disease vectors, under which the control program is concerned.
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Turner JD, Marriott AE, Hong D, O' Neill P, Ward SA, Taylor MJ. Novel anti-Wolbachia drugs, a new approach in the treatment and prevention of veterinary filariasis? Vet Parasitol 2020; 279:109057. [PMID: 32126342 DOI: 10.1016/j.vetpar.2020.109057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 02/09/2023]
Abstract
Filarial nematodes are tissue-dwelling parasitic worms that can cause a range of disfiguring pathologies in humans and potentially lethal infections of companion animals. The bacterial endosymbiont, Wolbachia, is present within most human and veterinary filarial pathogens, including the causative agent of heartworm disease, Dirofilaria immitis. Doxycycline-mediated drug targeting of Wolbachia leads to sterility, clearance of microfilariae and gradual death of adult filariae. This mode of action is attractive in the treatment of filariasis because it avoids severe host inflammatory adverse reactions invoked by rapid-killing anthelmintic agents. However, doxycycline needs to be taken for four weeks to exert curative activity. In this review, we discuss the evidence that Wolbachia drug targeting is efficacious in blocking filarial larval development as well as in the treatment of chronic filarial disease. We present the current portfolio of next-generation anti-Wolbachia candidates discovered through phenotypic screening of chemical libraries and validated in a range of in vitro and in vivo filarial infection models. Several novel chemotypes have been identified with selected narrow-spectrum anti-Wolbachia specificity and superior time-to-kill kinetics compared with doxycycline. We discuss the opportunities of developing these novel anti-Wolbachia agents as either cures, adjunct therapies or new preventatives for the treatment of veterinary filariasis.
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Affiliation(s)
- Joseph D Turner
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Amy E Marriott
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David Hong
- Department of Chemistry, University of Liverpool, UK
| | - Paul O' Neill
- Department of Chemistry, University of Liverpool, UK
| | - Steve A Ward
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Mark J Taylor
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Chandrasena TGAN, Premaratna R, Mallawaarachchi CH, Gunawardena NK, Gunathilaka PADHN, Abeyewickrama WY, de Silva NR. The Diversity of Human Dirofilariasis in Western Sri Lanka. BIOMED RESEARCH INTERNATIONAL 2019; 2019:9209240. [PMID: 31139659 PMCID: PMC6500613 DOI: 10.1155/2019/9209240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/25/2019] [Accepted: 04/04/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Human dirofilariasis is an emerging zoonosis in many countries. Dirofilariasis caused by Dirofilaria repens may present with diverse clinical manifestations in humans due to aberrant localization of worm lesions causing diagnostic dilemmas. The aim of this retrospective study was to describe and update the demography and clinical spectrum of human dirofilariasis in western Sri Lanka. Nematode or nematode fragments isolated from excision biopsies that were confirmed as D. repens at the Department of Parasitology, Faculty of Medicine, University of Kelaniya, Sri Lanka, between 2012 and 2018 were included. Data on age, gender, and clinical details were obtained from case files. Identity of worms was established by morphometry and cuticle characteristics on wet-mount preparation. Specimens from unusual case presentations were further analyzed by PCR with specific primers for internal transcribed spacer region 2 (ITS2) of the ribosomal DNA. RESULTS Sixteen nematode specimens isolated from subconjunctiva (n=2), subcutaneous (n=13) and intramuscular (n=1) locations were identified as D. repens by morphometry (average length 11.5 cm) and the characteristic longitudinal striations on cuticle visualized by microscopy. The age distribution of cases ranged from 1 to 65 years with a mean of 21.5. Females were more frequently affected (n=10, 62.5%) and worm locations were commonest in the orbital region (5/16) and scrotum (3/16). Imaging techniques were of use in detecting infections in deeper tissue levels. PCR analysis of DNA extracted from a worm in an intramuscular granuloma of the temporal region elicited the expected band at 484bp for D. repens. CONCLUSIONS Human dirofilariasis is on an upward trend in incidence. Imaging techniques were of use in clinical diagnosis and molecular speciation in establishing the species identity in unusual case presentations. We suggest a more conservative approach in the management of human dirofilariasis and recommend a one health approach for control.
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Affiliation(s)
| | - R. Premaratna
- Department of Medicine, Faculty of Medicine, University of Kelaniya, Sri Lanka
| | | | - N. K. Gunawardena
- Department of Parasitology, Faculty of Medicine, University of Kelaniya, Sri Lanka
| | | | | | - N. R. de Silva
- Department of Parasitology, Faculty of Medicine, University of Kelaniya, Sri Lanka
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Nochot H, Loimek S, Priyavoravong P, Wongkamchai S, Sarasombath PT. Therapeutic efficacy of doxycycline in domestic cats naturally infected with Brugia malayi in field condition. Exp Parasitol 2019; 200:73-78. [PMID: 30953626 DOI: 10.1016/j.exppara.2019.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/11/2019] [Accepted: 03/26/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVE The aim of this study was to evaluate the efficacy of oral doxycycline treatment for Brugia malayi as measured by microfilarial and filarial DNA clearance in naturally infected domestic cats. METHODS This study included 8 domestic cats that lived with families that resided in Tak Bai District of Narathiwat Province, which is located in Southern Thailand. The study area is a known B. malayi endemic area. All study cats received doxycycline treatment doses by their respective owners according to a previously described protocol. Briefly, doxycycline (VibraVet@) was given orally once a day during weeks 1-4, 10-11, and 16-17. Blood collections were performed at baseline before treatment, and then every month for 12 months after the initial dose of doxycycline to assess microfilaraemia by Giemsa stain, and filarial DNA detection by high-resolution melt (HRM) real-time polymerase chain reaction (PCR). RESULTS One month after the start of doxycycline treatment, five of eight cats were negative for microfilaraemia, and 4 of those were negative for filarial DNA. All cats receiving doxycycline treatment were negative for microfilaria by Giemsa stain, and for filarial DNA by HRM real-time PCR within 8 months after receiving the initial dose of doxycycline treatment. CONCLUSION Administration of oral doxycycline to domestic cats naturally infected with B. malayi in disease endemic areas can significantly reduce microfilaraemia at 1 month and filarial DNA was undetectable by 8 months after the initial dose of doxycycline treatment. No recurrence of microfilaraemia or filarial DNA was observed in study cats at 1 year after the start of doxycycline. Included cats appeared to tolerate doxycycline (VibraVet@) well, with no adverse drug reactions reported by any study cat owner.
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Affiliation(s)
- Hathai Nochot
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
| | - Sumat Loimek
- Office of Disease Prevention and Control Region 12 Songkhla, Department of Disease Control, Ministry of Public Health, Songkhla, Thailand.
| | | | - Sirichit Wongkamchai
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
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A preliminary survey of filarial parasites in dogs and cats in Sri Lanka. PLoS One 2018; 13:e0206633. [PMID: 30388188 PMCID: PMC6214534 DOI: 10.1371/journal.pone.0206633] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/16/2018] [Indexed: 11/19/2022] Open
Abstract
Human brugian filariasis has re-emerged in Sri Lanka after a quiescent period of four decades. This study investigated the prevalence of canine and feline filarial parasites in three localities with human sub-periodic brugian filariasis, in order to determine their potential reservoir status. All reachable dogs and cats, both stray and domestic, within a 350m radius of an index case of brugian filariasis in three locations (Madampe, Wattala and Weliweriya) were screened for microfilariae using Giemsa stained thick blood smears. A representative sample of canine and feline blood samples positive for Brugia spp. microfilariae by microscopy, from each of the three locations, were further analyzed by PCR with specific primers for internal transcribed spacer region 2 (ITS2) of the ribosomal DNA. A total of 250 dogs and 134 cats were screened. The overall microfilaraemia rates were high among both dogs (68.8%) and cats (47.8%). The prevalence of microfilaraemia was significantly higher among dogs than cats (p<0.05). Two filarial species were identified based on morphology of microfilariae: Dirofilaria (Nochtiella) repens (dogs, 54.4% and cats, 34.3%) and Brugia spp. (dogs, 51.6% and cats, 30.6%). PCR analysis of canine (n = 53) and feline (n = 24) samples elicited bands in the region of 615bp, which confirmed Brugia malayi infection. Co-infection with D.(N.) repens was detected by PCR with an additional band at 484bp, in 36 canine and 17 feline samples. Overall microfilaraemia rates of dogs (81.8%) and cats (75%) in Madampe (rural) were significantly higher than in urbanized Wattala (dogs, 62.4% and cats, 26.0%) (p<0.05). High rates of zoonotic filarial infections strongly implicate dogs and cats as potential reservoirs for human dirofilariasis and brugian filariasis in Sri Lanka.
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Morbidity management and disability prevention for lymphatic filariasis in Sri Lanka: Current status and future prospects. PLoS Negl Trop Dis 2018; 12:e0006472. [PMID: 29746479 PMCID: PMC5963805 DOI: 10.1371/journal.pntd.0006472] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/22/2018] [Accepted: 04/23/2018] [Indexed: 11/19/2022] Open
Abstract
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. Lymphatic filariasis (LF) is a tropical disease causing swelling of limbs (lymphoedema, elephantiasis) and male genitalia (hydrocele). It is a disabling and deforming disease caused by parasitic worms transmitted by mosquitoes. The Sri Lankan Anti Filariasis Campaign was successful in reducing LF transmission to very low levels by annual mass drug administration, resulting in recent achievement of elimination status. The other pillar of LF elimination is the management of morbidity and disability prevention (MMDP) among those with lymphatic filarial disease. The strengths, weaknesses and threats of the MMDP program were evaluated and opportunities for improvement were explored in June 2017. The filariasis clinics established in the endemic area, providing care for patients with lymphoedema and elephantiasis, were identified as the main strength. Hospital surgical units were important in the treatment of hydrocele. The weaknesses were low accessibility of clinics, incomplete coverage of endemic districts, lack of facilities for rehabilitation and lack of morbidity targets. The threats were diversion of staff and resources, under-utilization of clinics, social stigma and loss of alliances. Enhanced commitment to improve coverage and access to clinics in the endemic areas, wider publicity, referral systems, integration of MMDP into other disease management services, collaborations with welfare organizations and research groups were the opportunities identified.
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