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  1. Leptospirosis in Malaya. II. Antigenic analysis of 110 leptospiral strains and other serologic studies
    ALEXANDER AD, EVANS LB, TOUSSAINT AJ, MARCHWICKI RH, McCRUMB FR
    Am J Trop Med Hyg, 1957 Sep;6(5):871-89.
    PMID: 13470208
    Matched MeSH terms: Leptospirosis/immunology*
  2. A preliminary study of the status of leptospirosis in the Malaysian Armed forces
    Tan DS, Lopes DA
    Southeast Asian J. Trop. Med. Public Health, 1972 Jun;3(2):208-11.
    PMID: 5082848
    Matched MeSH terms: Leptospirosis/immunology
  3. Leptospirosis in rural West Malaysia
    Tan DS
    Med J Malaya, 1970 Jun;24(4):261-6.
    PMID: 4248346
    Matched MeSH terms: Leptospirosis/immunology
  4. Fulltext In-house ELISA screening using a locally-isolated Leptospira in Malaysia: determination of its cut-off points
    Tan XT, Amran F, Chee Cheong K, Ahmad N
    BMC Infect Dis, 2014;14:563.
    PMID: 25338815 DOI: 10.1186/s12879-014-0563-7
    Leptospirosis is a zoonotic disease caused by Leptospira species and is distributed globally. Microscopic agglutination test (MAT) is the serological 'gold standard' for diagnosis of leptospirosis but it is time-consuming and labour-intensive. An alternative serological method that is rapid, sensitive and specific is important for early treatment to reduce morbidity and mortality. The use of local Leptospira isolation may improve the sensitivity and specificity of the test because it may varies from one geographical region to another region. The objective of this study was to determine the sensitivity, specificity and cut-off points for an in-house Immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) using a locally isolated Leptospiral strain IMR/175 as the antigen for the detection of anti-Leptospiral IgM.
    Matched MeSH terms: Leptospirosis/immunology
  5. Fulltext Sensitized-erythrocyte-lysis (SEL) test as an epidemiological tool for human leptospirosis serological surveys
    Tan DS
    Bull World Health Organ, 1969;40(6):899-902.
    PMID: 5307602
    Epidemiological studies of human leptospirosis have generally been limited to countries with specialized laboratories employing the microscopic-agglutination (MA) test. The sensitized-erythrocyte-lysis (SEL) test is much simpler for routine hospital laboratories to carry out and it has been found valuable in the diagnosis of human leptospirosis. This paper reports the results of studies of the SEL test as an epidemiological tool in serological surveys.The results showed that the significant SEL titre was 1:80 and that the sensitivity of the test depended possibly on the antigen preparation and the amount of complement used. Most of the SEL antibodies were found to persist at significant titres for about 1 year after active infection, but less than half persisted longer than that. The SEL test is therefore useful for detecting recent infections and for indicating that stability of leptospirosis in an area.The endemicity of leptospirosis in West Malaysia was confirmed by the SEL test, based on the employment of 1:80 as the significant titre.
    Matched MeSH terms: Leptospirosis/immunology
  6. 3D modelling of the pathogenic Leptospira protein LipL32: A bioinformatics approach
    Kumaran SK, Bakar MFA, Mohd-Padil H, Mat-Sharani S, Sakinah S, Poorani K, et al.
    Acta Trop, 2017 Dec;176:433-439.
    PMID: 28941729 DOI: 10.1016/j.actatropica.2017.09.011
    Leptospirosis is a widespread zoonotic disease caused by pathogenic Leptospira species (Leptospiraceae). LipL32 is an abundant lipoprotein from the outer membrane proteins (OMPs) group, highly conserved among pathogenic and intermediate Leptospira species. Several studies used LipL32 as a specific gene to identify the presence of leptospires. This research was aimed to study the characteristics of LipL32 protein gene code, to fill the knowledge gap concerning the most appropriate gene that can be used as antigen to detect the Leptospira. Here, we investigated the features of LipL32 in fourteen Leptospira pathogenic strains based on comparative analyses of their primary, secondary structures and 3D modeling using a bioinformatics approach. Furthermore, the physicochemical properties of LipL32 in different strains were studied, shedding light on the identity of signal peptides, as well as on the secondary and tertiary structure of the LipL32 protein, supported by 3D modelling assays. The results showed that the LipL32 gene was present in all the fourteen pathogenic Leptospira strains used in this study, with limited diversity in terms of sequence conservation, hydrophobic group, hydrophilic group and number of turns (random coil). Overall, these results add basic knowledge to the characteristics of LipL32 protein, contributing to the identification of potential antigen candidates in future research, in order to ensure prompt and reliable detection of pathogenic Leptospira species.
    Matched MeSH terms: Leptospirosis/immunology*
  7. Leptospirosis in human: Biomarkers in host immune responses
    Vk C, Ty L, Wf L, Ywy WS, An S, S Z, et al.
    Microbiol Res, 2018 Mar;207:108-115.
    PMID: 29458845 DOI: 10.1016/j.micres.2017.11.015
    Leptospirosis remains one of the most widespread zoonotic diseases caused by spirochetes of the genus Leptospira, which accounts for high morbidity and mortality globally. Leptospiral infections are often found in tropical and subtropical regions, with people exposed to contaminated environments or animal reservoirs are at high risk of getting the infection. Leptospirosis has a wide range of clinical manifestations with non-specific signs and symptoms and often misdiagnosed with other acute febrile illnesses at early stage of infection. Despite being one of the leading causes of zoonotic morbidity worldwide, there is still a gap between pathogenesis and human immune responses during leptospiral infection. It still remains obscure whether the severity of the infection is caused by the pathogenic properties of the Leptospira itself, or it is a consequence of imbalance host immune factors. Hence, in this review, we seek to summarize the past and present milestone findings on the biomarkers of host immune response aspects during human leptospiral infection, including cytokine and other immune mediators. A profound understanding of the interlink between virulence factors and host immune responses during human leptospirosis is imperative to identify potential biomarkers for diagnostic and prognostic applications as well as designing novel immunotherapeutic strategies in future.
    Matched MeSH terms: Leptospirosis/immunology*
  8. Fulltext Production and characterization of a polyclonal antibody of anti-rLipL21-IgG against leptospira for early detection of acute leptospirosis
    Seenichamy A, Bahaman AR, Mutalib AR, Khairani-Bejo S
    Biomed Res Int, 2014;2014:592858.
    PMID: 24860824 DOI: 10.1155/2014/592858
    Leptospirosis is one of the zoonotic diseases in animals and humans throughout the world. LipL21 is one of the important surface-exposed lipoproteins in leptospires and the most effective cross protective immunogenic antigen. It is widely considered as a diagnostic marker for leptospirosis. In this study, we evaluated the serodiagnostic potential of LipL21 protein of Leptospira interrogans serovar Pomona. We have successfully amplified, cloned, and expressed LipL21 in E. coli and evaluated its specificity by immunoblotting. Purified recombinant LipL21 (rLipL21) was inoculated into rabbits for the production of polyclonal antibody. Characterization of the purified IgG antibody against rLipL21 was performed by cross reactivity assay. Only sera from leptospirosis patients and rabbit hyperimmune sera recognized rLipL21 while the nonleptospirosis control sera showed no reaction in immunoblotting. We confirmed that anti-rLipL21-IgG antibody cross reacted with and detected only pathogenic leptospiral species and it did not react with nonpathogenic leptospires and other bacterial species. Results observed showed that anti-rLipL21-IgG antibody has high specificity and sensitivity to leptospires. The findings indicated that the antibody could be used in a diagnostic assay for detection of leptospires or their proteins in the early phase of infection.
    Matched MeSH terms: Leptospirosis/immunology*
  9. Fulltext Work Environment-Related Risk Factors for Leptospirosis among Plantation Workers in Tropical Countries: Evidence from Malaysia
    Mohd Ridzuan J, Aziah BD, Zahiruddin WM
    Int J Occup Environ Med, 2016 07;7(3):156-63.
    PMID: 27393322 DOI: 10.15171/ijoem.2016.699
    BACKGROUND: Leptospirosis is a zoonotic disease that is recognized as a re-emerging global public health issue, especially in tropical and subtropical countries. Malaysia, for example, has increasingly registered leptospirosis cases, outbreaks, and fatalities over the past decade. One of the major industries in the country is the palm oil sector, which employs numerous agricultural workers. These laborers are at a particularly high risk of contracting the disease.

    OBJECTIVE: To identify the work environment-related risk factors for leptospirosis infection among oil palm plantation workers in Malaysia.

    METHODS: A cross-sectional study involving 350 workers was conducted. The participants were interviewed and administered a microscopic agglutination test. Seropositivity was determined using a cut-off titer of ≥1:100.

    RESULTS: 100 of 350 workers tested positive for leptospiral antibodies, hence, a seroprevalence of 28.6% (95% CI 23.8% to 33.3%). The workplace environment-related risk factors significantly associated with seropositive leptospirosis were the presence of cows in plantations (adjusted OR 4.78, 95% CI 2.76 to 8.26) and the presence of a landfill in plantations (adjusted OR 2.04, 95% CI 1.22 to 3.40).

    CONCLUSION: Preventing leptospirosis incidence among oil palm plantation workers necessitates changes in policy on work environments. Identifying modifiable factors may also contribute to the reduction of the infection.

    Matched MeSH terms: Leptospirosis/immunology
  10. Leptospirosis: Molecular trial path and immunopathogenesis correlated with dengue, malaria and mimetic hemorrhagic infections
    Priya SP, Sakinah S, Sharmilah K, Hamat RA, Sekawi Z, Higuchi A, et al.
    Acta Trop, 2017 Dec;176:206-223.
    PMID: 28823908 DOI: 10.1016/j.actatropica.2017.08.007
    Immuno-pathogenesis of leptospirosis can be recounted well by following its trail path from entry to exit, while inducing disastrous damages in various tissues of the host. Dysregulated, inappropriate and excessive immune responses are unanimously blamed in fatal leptospirosis. The inherent abilities of the pathogen and inabilities of the host were debated targeting the severity of the disease. Hemorrhagic manifestation through various mechanisms leading to a fatal end is observed when this disease is unattended. The similar vascular destructions and hemorrhage manifestations are noted in infections with different microbes in endemic areas. The simultaneous infection in a host with more than one pathogen or parasite is referred as the coinfection. Notably, common endemic infections such as leptospirosis, dengue, chikungunya, and malaria, harbor favorable environments to flourish in similar climates, which is aggregated with stagnated water and aggravated with the poor personal and environmental hygiene of the inhabitants. These factors aid the spread of pathogens and parasites to humans and potential vectors, eventually leading to outbreaks of public health relevance. Malaria, dengue and chikungunya need mosquitoes as vectors, in contrast with leptospirosis, which directly invades human, although the environmental bacterial load is maintained through other mammals, such as rodents. The more complicating issue is that infections by different pathogens exhibiting similar symptoms but require different treatment management. The current review explores different pathogens expressing specific surface proteins and their ability to bind with array of host proteins with or without immune response to enter into the host tissues and their ability to evade the host immune responses to invade and their affinity to certain tissues leading to the common squeal of hemorrhage. Furthermore, at the host level, the increased susceptibility and inability of the host to arrest the pathogens' and parasites' spread in different tissues, various cytokines accumulated to eradicate the microorganisms and their cellular interactions, the antibody dependent defense and the susceptibility of individual organs bringing the manifestation of the diseases were explored. Lastly, we provided a discussion on the immune trail path of pathogenesis from entry to exit to narrate the similarities and dissimilarities among various hemorrhagic fevers mentioned above, in order to outline future possibilities of prevention, diagnosis, and treatment of coinfections, with special reference to endemic areas.
    Matched MeSH terms: Leptospirosis/immunology
  11. Role of 72 kDa protein of Leptospira interrogans as a diagnostic marker in acute leptospirosis
    Riazi M, Zainul FZ, Bahaman AR, Amran F, Khalilpour A
    Indian J Med Res, 2014 Feb;139(2):308-13.
    PMID: 24718408
    Leptospirosis is a widespread zoonotic disease and a public health problem, particularly in tropical and subtropical countries. Varied clinical manifestations of the disease frequently lead to misdiagnosis resulting in life-threatening multi-organ complications. Therefore, early laboratory investigation using an appropriate diagnostic approach is crucial. In the present study, a potential protein marker was identified and evaluated for its usefulness in the serodiagnosis of acute leptospirosis.
    Matched MeSH terms: Leptospirosis/immunology
  12. Fulltext Seroprevalence of Anti-Leptospira IgG and IgM Antibodies and Risk Assessment of Leptospirosis among Urban Poor Communities in Kuala Lumpur, Malaysia
    Sahimin N, Sharif SA, Mohd Hanapi IR, Nai Chuan S, Lewis JW, Douadi B, et al.
    Am J Trop Med Hyg, 2019 12;101(6):1265-1271.
    PMID: 31628737 DOI: 10.4269/ajtmh.19-0003
    Leptospirosis is a zoonotic bacterial disease caused by pathogenic species of the genus Leptospira. Disease incidence is known to be attributed to environmental and social conditions which promote the spread of reservoir hosts, primarily rodents. A well-being program was conducted to determine the seroprevalence and risk factors associated with leptospirosis in urban poor communities occupying low-cost flat accommodation and squatter settlements in the vicinity of Wilayah Persekutuan, Kuala Lumpur. Blood samples from a total of 532 volunteers were screened for the detection of IgG and IgM antibodies against leptospirosis using ELISA. Demographic data were collected for each participant through a questionnaire survey before blood collection. The overall seroprevalence was low (12.6%, n = 67/532; 95% CI: 9.9-15.7%), with 8.1% (n = 43/532) being seropositive for anti-Leptospira IgG, indicating previous infection, and 4.9% (n = 26/532) for anti-Leptospira IgM, indicating current infection. Two significant factors such as host age (P ≤ 0.01) and knowledge of disease transmission (P = 0.017) significantly influenced the presence of anti-Leptospira IgM, whereas the detection of anti-IgG indicated the presence of clean drinking water sources (P = 0.043). Despite the low prevalence, the transmission of leptospirosis does occur among urban poor communities, suggesting the need for undertaking public awareness programs.
    Matched MeSH terms: Leptospirosis/immunology*
  13. Antigenic potential of a recombinant polyvalent DNA vaccine against pathogenic leptospiral infection
    Garba B, Bahaman AR, Zakaria Z, Bejo SK, Mutalib AR, Bande F, et al.
    Microb Pathog, 2018 Nov;124:136-144.
    PMID: 30138761 DOI: 10.1016/j.micpath.2018.08.028
    Leptospirosis is a serious epidemic disease caused by pathogenic Leptospira species. The disease is endemic in most tropical and sub-tropical regions of the world. Currently, there is no effective polyvalent vaccine for prevention against most of the circulating serovars. Moreover, development of an efficient leptospiral vaccine capable of stimulating cross-protective immune responses against a wide range of serovars remains a daunting challenge. This, in part, is associated with the extensive diversity and variation of leptospiral serovars from region to region. In this study, a multi-epitope DNA vaccine encoding highly immunogenic epitopes from LipL32 and LipL41 was designed using in-silico approach. The DNA encoding antigenic epitopes was constructed from conserved pathogenic Leptospira genes (LipL32 and LipL41). Immunization of golden Syrian hamsters with the multi-epitope chimeric DNA vaccine resulted in the production of both agglutinating and neutralizing antibodies as evidence by MAT and in-vitro growth inhibition tests respectively. The antibodies produced reacted against eight different serovars and significantly reduced renal colonization following in vivo challenge. The vaccine was also able to significantly reduce renal colonization which is a very important factor responsible for persistence of leptospires among susceptible and reservoir animal hosts. In conclusion, the leptospiral multi-epitope chimeric DNA vaccine can serve as a potentially effective and safe vaccine against infection with different pathogenic leptospiral serovars.
    Matched MeSH terms: Leptospirosis/immunology
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