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  1. Evaluation of Leptospira biflexa antigens for screening human sera by the microscopic agglutination (MA) test in comparison with the sensitized-erythrocyte-lysis (SEL) test
    Tan DS, Welch QB
    Southeast Asian J Trop Med Public Health, 1974 Mar;5(1):12-6.
    PMID: 4839075
    Matched MeSH terms: Leptospira/immunology*
  2. Fulltext A hospital-based study on seroprevalence of leptospirosis among febrile cases in northeastern Malaysia
    Rafizah AA, Aziah BD, Azwany YN, Imran MK, Rusli AM, Nazri SM, et al.
    Int J Infect Dis, 2013 Jun;17(6):e394-7.
    PMID: 23357246 DOI: 10.1016/j.ijid.2012.12.012
    To determine the seroprevalence of leptospirosis among febrile inpatient cases in northeastern Malaysia.
    Matched MeSH terms: Leptospira/immunology
  3. Leptospirosis in a caver returned from Sarawak, Malaysia
    Mortimer RB
    Wilderness Environ Med, 2005;16(3):129-31.
    PMID: 16209467
    This article describes a case of leptospirosis in a man who returned from caving in Sarawak, Malaysia, and includes a discussion of epidemiology, pathophysiology, diagnosis, prevention, and treatment. The patient presented with symptoms of leptospirosis, which was confirmed by microhemagglutination titers. He became infected despite taking doxycycline daily for malaria prophylaxis. Leptospirosis is an important consideration in any returned traveler with fever. The spirochete spreads from animals to humans via water. Caving in tropical endemic zones may increase exposure risk due to the combination of multiple skin abrasions with immersions. Water in caves may increase infection risk because of increased water pH. Standard prophylaxis may be inadequate in cases of high-risk exposures.
    Matched MeSH terms: Leptospira/immunology
  4. 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: Leptospira/immunology
  5. 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: Leptospira/immunology*
  6. 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: Leptospira/immunology*
  7. Seroprevalence of Leptospirosis in Working Dogs
    Lau SF, Wong JY, Khor KH, Roslan MA, Abdul Rahman MS, Bejo SK, et al.
    Top Companion Anim Med, 2017 Dec;32(4):121-125.
    PMID: 29525230 DOI: 10.1053/j.tcam.2017.12.001
    Working dogs are canine animals that have been trained to assist human beings in carrying out various tasks. They help in guarding property, performing rescues, assisting the visually impaired or physically handicapped, searching for drugs, explosives, and others. Leptospirosis is one of the most widespread zoonotic diseases in the world and a commonly occurring disease of the tropics and subtropics. In Malaysia, all working dogs are normally vaccinated with serovars, Pomona, Icterohaemorrhagiae, Canicola, and Grippotyphosa based on protocols recommended from other countries. The duration of immunity in vaccinated dogs for Leptospira can last up to 13 months; however, there is no full crossprotection between the different serovars. Five representative canine units from different government agencies in Malaysia (n = 96 dogs) were recruited in this study. For detection, the microscopic agglutination test was performed by incubating the serum from dogs with various serovars of leptospires, namely, Icterohaemorrhagiae, Canicola, Pomona, Grippotyphosa, Australis, Bataviae, Javanica, Tarassovi, Hebdomadis, Lai, and Pyrogenes. The plasma obtained was used for polymerase chain reaction (PCR) analysis, for the detection of 16S rRNA, and lipL 32 genes of Leptospira. Out of the 96 dogs sampled, only 3 dogs were positive toward serovars, Australis, Bataviae, and Javanica, based on the cutoff point at 1:80. The seroprevalence of canine leptospirosis in this population was 3.1% (n = 3/96). However, all 96 blood samples of working dogs tested negative for both pathogenic and nonpathogenic Leptospira genes. The results revealed that, by vaccination alone, working dogs were not fully protected against leptospirosis and could pose a risk to dog handlers. A preventative and control protocol for leptospirosis is warranted, and its implementation should be monitored and improved accordingly from time to time, in order to maintain a healthy condition in both working dogs and their handlers.
    Matched MeSH terms: Leptospira/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: Leptospira/immunology*
  9. Acute renal failure after a holiday in the tropics
    Guron G, Holmdahl J, Dotevall L
    Clin. Nephrol., 2006 Dec;66(6):468-71.
    PMID: 17176921 DOI: 10.5414/cnp66468
    A 20-year-old, previously healthy woman, presented with high fever, headache and myalgia 3 days after her return from a holiday in Southeast Asia. Laboratory data on admission demonstrated a pronounced increase in plasma creatinine, marked thrombocytopenia and moderately elevated liver aminotransferases. After having ruled out malaria, dengue fever was primarily suspected and supportive intravenous fluid therapy was initiated. Still, 1 day after admission, platelet counts dropped even further and she became anuric although she did not appear hypovolemic. On day 2 after admission, urine production commenced spontaneously and the patient slowly recovered. All laboratory test results had returned to normal approximately 2 months later. Serological analysis for dengue fever was negative. It turned out that the patient had been trekking in the jungle while in Thailand and we, therefore, analyzed serology for Leptospira spirochetes which was clearly positive. The patient was diagnosed with leptospirosis which is a serious condition associated with a high mortality when complicated by acute renal failure. Differential diagnoses in patients with acute renal failure and tropical infections are reviewed. The importance of early recognition of leptospirosis, and prompt treatment with antibiotics in suspected cases, is emphasized.
    Matched MeSH terms: Leptospira/immunology
  10. 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: Leptospira/immunology
  11. Detection and distribution of anti-leptospiral antibody among dogs and their handlers
    Goh SH, Khor KH, Ismail R, Megat Abdul Rani PA, Mohd Mohidin TB, Bahaman AR, et al.
    Trop Biomed, 2020 Dec 01;37(4):1074-1082.
    PMID: 33612759 DOI: 10.47665/tb.37.4.1074
    The incidence of leptospirosis seems to be on the rise and could be an alarming indirect indication of a global re-emergence. It is a potential public health threat when dogs are speculated to be involved in the transmission of leptospirosis through possible subclinical harbouring of Leptospira spp. and subsequent shedding into the environment. This study aimed to detect anti-leptospiral antibodies among dogs and their handlers using the microscopic agglutination test (MAT). Blood samples from 266 apparently healthy dogs and 194 dog handlers were collected at four working dog organisations and four dog shelters. Serum samples were tested using MAT against 20 leptospiral serovars with a cut-off titre >=1:100 (dog) and >=1:50 (dog handlers). Seventy dogs (70/266; 26.3%) were seropositive mainly against serovars Icterohaemorrhagiae, Ballum, Bataviae and Javanica (titres ranged: 1:100-1:800). Sixty-seven dog handlers (67/194; 34.5%) were seropositive mainly against serovars Grippotyphosa, Icterohaemorrhagiae and Malaysia (titres ranged: 1:50-1:200). Dogs were seropositive due to exposure, vaccination or active infection. Seropositive dog handlers could indicate exposure or active infection. This shows the potential of dogs in maintaining and spreading the infection in Malaysia. Due to the occupational risk as a result of frequent contact with dogs and exposure to contaminated environments, dog handlers should be made aware of the presence of this zoonotic disease.
    Matched MeSH terms: Leptospira/immunology
  12. Serological and bacteriological study of leptospiral infection in a cattle herd in Malaysia
    Bahaman AR, Ibrahim AL
    Vet Rec, 1986 Sep 27;119(13):325-6.
    PMID: 3776042
    Matched MeSH terms: Leptospira/immunology
  13. Serological Prevalence of Leptospirosis Among Rural Communities in the Rejang Basin, Sarawak, Malaysia
    Suut L, Mazlan MN, Arif MT, Yusoff H, Abdul Rahim NA, Safii R, et al.
    Asia Pac J Public Health, 2016 07;28(5):450-7.
    PMID: 27183976 DOI: 10.1177/1010539516648003
    Leptospirosis is an important zoonotic disease globally and is endemic in Malaysia. A study was conducted in the Rejang basin of Sarawak from June 2011 to May 2013 to determine the seroprevalence of leptospirosis among the communities and dominant infecting Leptospira serovars. A total of 508 human sera were analyzed using ELISA and the microscopic agglutination test (MAT). The seroprevalence of leptospirosis in the study area was 37.4%, with the highest prevalence in Kapit division. More women were positive for leptospirosis (59.5%), and the mean age of seropositive individuals was 42.2 (SD = 18.7) years. Antibody titers between 1:50 and 1:1600 were reported, and serovars djasiman (22.1%), shermani (13.2%), and pomona (7.9%) predominated, with varied distribution between geographical locations. This study highlighted the endemicity and diversity of existing Leptospira serovars within the community. This information should be communicated to local health personnel and communities at risk, and rapid diagnostic capability should be made available to local health facilities.
    Matched MeSH terms: Leptospira/immunology
  14. The bacteriological prevalence of leptospiral infection in cattle and buffaloes in West Malaysia
    Bahaman AR, Ibrahim AL, Stallman ND, Tinniswood RD
    Epidemiol Infect, 1988 Apr;100(2):239-46.
    PMID: 3356222
    A cross-sectional bacteriological survey of cattle in West Malaysia revealed 14.4% (32/222) had leptospiral infection. Isolates were obtained from all except one herd with prevalence of infection in herds ranging from 0-44.8%. A small number of buffalo urine samples were examined and all of them were found to be negative. A leptospiral isolate obtained from a bovine kidney proved to be a new serovar of Leptospira interrogans and the name unipertama was assigned to it. Six other leptospiral serovars were isolated, namely canicola, australis, javanica, ballum, pomona and hardjo. All six serovars were isolated for the first time in cattle in Malaysia. Cattle in Malaysia appear to be the maintenance host for serovar hardjo. The presence of the other serovars in cattle was probably due to contact with the maintenance hosts, pigs for serovar pomona and rodents for the other three serovars. It appears that the epidemiology of leptospiral infection in cattle in Malaysia is similar to that reported overseas.
    Matched MeSH terms: Leptospira/immunology
  15. An outbreak of leptospirosis among reserve military recruits, Hulu Perdik, Malaysia
    Neela VK, Azhari NN, Joseph N, Mimie NP, Ramli SNA, Mustapha NF, et al.
    Eur J Clin Microbiol Infect Dis, 2019 Mar;38(3):523-528.
    PMID: 30680558 DOI: 10.1007/s10096-018-03450-6
    Here, we investigated an outbreak of leptospirosis among reserve military recruits that occurred following a survival exercise in the Hulu Perdik forest within the Hulu Langat district, Kuala Lumpur, Malaysia. Blood samples from the 12 patients that presented symptoms for febrile illness on clinical examination were subjected to laboratory investigation, comprising Lepto IgM rapid test, IgM ELISA, and microscopic agglutination test (MAT). All these patients were interviewed for possible risk factors for leptospirosis. Rodent trapping and environmental sampling for possible isolation of leptospires in the outbreak site was performed. The isolated leptospires were genetically characterized and investigated for the potential epidemiological link with human leptospirosis. Among the 12 patients, two (2/12; 16.6%) were confirmed positive for leptospirosis by microscopic agglutination test (MAT with titers 400-800; serovar autumnalis and hardjobovis). Two Leptospira species from rodents (L. interrogans and L. borgpetersenii) and two from the environment (L. kmetyi and L. wolffii) were identified. The possible epidemiological link between human serovars and animal Leptospira species indicates rodents as the potential reservoir while the environment (soil and water) serves as a transmission route. This investigation highlights the robust presence of pathogenic leptospires on Malaysian environment and rodents which may present the risk of infection, especially among high-risk individuals. Hence, occupational risk individuals are cautioned to observe appropriate preventive measures including prophylaxis and seek immediate medical attention for any illness following similar activities.
    Matched MeSH terms: Leptospira/immunology
  16. 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: Leptospira/immunology*
  17. Development of monoclonal antibodies against recombinant LipL21 protein of pathogenic Leptospira through phage display technology
    Mohd Ali MR, Sum JS, Aminuddin Baki NN, Choong YS, Nor Amdan NA, Amran F, et al.
    Int J Biol Macromol, 2021 Jan 31;168:289-300.
    PMID: 33310091 DOI: 10.1016/j.ijbiomac.2020.12.062
    Leptospirosis is a potentially fatal zoonosis that is caused by spirochete Leptospira. The signs and symptoms of leptospirosis are usually varied, allowing it to be mistaken for other causes of acute febrile syndromes. Thus, early diagnosis and identification of a specific agent in clinical samples is crucial for effective treatment. This study was aimed to develop specific monoclonal antibodies against LipL21 antigen for future use in leptospirosis rapid and accurate immunoassay. A recombinant LipL21 (rLipL21) antigen was optimized for expression and evaluated for immunogenicity. Then, a naïve phage antibody library was utilized to identify single chain fragment variable (scFv) clones against the rLipL21 antigen. A total of 47 clones were analysed through monoclonal phage ELISA. However, after taking into consideration the background OD405 values, only 4 clones were sent for sequencing to determine human germline sequences. The sequence analysis showed that all 4 clones are identical. The in silico analysis of scFv-lip-1 complex indicated that the charged residues of scFv CDRs are responsible for the recognition with rLipL21 epitopes. The generated monoclonal antibody against rLipL21 will be evaluated as a detection reagent for the diagnosis of human leptospirosis in a future study.
    Matched MeSH terms: Leptospira/immunology*
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