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Classification of leptospiral isolates from Malaya, Thailand and North Borneo

ALEXANDER AD, WETMORE PW, EVANS LB, JEFFRIES H, GLEISER CA

Am J Trop Med Hyg, 1955 May;4(3):492-506.
PMID: 14376775
Matched MeSH terms: Leptospira*
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: Leptospira*; Leptospirosis/immunology*
Fulltext Environmental risk factors of leptospirosis in urban settings: a systematic review protocol

Abdul Mutalip MH, Mahmud MAF, Lodz NA, Yoep N, Muhammad EN, Ahmad A, et al.

BMJ Open, 2019 01 21;9(1):e023359.
PMID: 30670512 DOI: 10.1136/bmjopen-2018-023359

INTRODUCTION: Leptospirosis is the most common zoonotic disease that causes morbidity and mortality worldwide. The disease can cause sporadic epidemics and recent epidemics have become more apparent in urban localities. There is lack of documented evidence on the specific risk factors of leptospirosis infection among the urbanites, thereby impeding initiatives for prevention in urban settings. We aim to systematically search published articles and synthesise evidence on the risk factors associated with leptospirosis infection among the susceptible populations in urban localities, particularly to identify the risk factors of non-recreational leptospirosis infection.
METHODS AND ANALYSIS: We will conduct a systematic review of observational studies that investigated environmental risk factors of leptospirosis in urban localities. The search will be performed for any eligible articles from selected electronic databases from 1970 until May 2018. The study will include any studies that investigated risk factors of confirmed leptospirosis cases who acquired the infection in urban locality, particularly exposures from the non-recreational and non-water-related activities. Study selection and reporting will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Meta-Analysis of Observational Studies in Epidemiology guideline. All data will be extracted using a standardised data extraction form and quality of the studies will be assessed using the Newcastle-Ottawa Scale guideline. Descriptive and meta-analysis will be performed by calculating the standardised median ORs and risk ratios for types of the non-recreational risk factors stratified by social, living conditions and environmental exposures, types of reservoirs and transmissions and types of activities and employments associated with leptospirosis infection in urban locality.
ETHICS AND DISSEMINATION: No primary data will be collected thus no formal ethical approval is required. The results will be disseminated though a peer-reviewed publication and conference presentation.
PROSPERO REGISTRATION NUMBER: CRD42018090820.

Matched MeSH terms: Leptospira/isolation & purification
Fulltext Rapid diagnosis of leptospirosis by multiplex PCR

Ahmed SA, Sandai DA, Musa S, Hoe CH, Riadzi M, Lau KL, et al.

Malays J Med Sci, 2012 Jul;19(3):9-16.
PMID: 23610544 MyJurnal

Traditionally, the most common diagnostic approach used for diagnosing leptospirosis was the demonstration of immune-seroconversion in acute and convalescent patient serum samples. Recently, a variety of molecular techniques, including conventional and real-time polymerase chain reaction (PCR), have been developed for the specific detection of pathogenic bacteria from the genus Leptospira. PCR is a sensitive, specific, and rapid technique that has been successfully used to detect several microorganisms; including those of clinical significance.

Matched MeSH terms: Leptospira
Fulltext First report of pathogenic Leptospira spp. isolated from urine and kidneys of naturally infected cats

Alashraf AR, Lau SF, Khairani-Bejo S, Khor KH, Ajat M, Radzi R, et al.

PLoS One, 2020;15(3):e0230048.
PMID: 32155209 DOI: 10.1371/journal.pone.0230048

Leptospirosis is one of the most widespread zoonotic diseases and can infect both humans and animals worldwide. Healthy cat, as a potential source of exposure to humans, are likely underestimated owing to the lack of overt clinical signs associated with Leptospira spp. infection in this species. The aim of the study was to determine the exposure, shedding, and carrier status of leptospires in shelter cats in Malaysia by using serological, molecular, and bacteriological methods. For this study, 82 healthy cats from two shelters were sampled. The blood, urine, and kidneys were tested using the microscopic agglutination test (MAT), polymerase chain reaction (PCR), and bacterial culture. On the basis of serological, molecular, and/or culture techniques, the total detection of leptospiral infection was 29.3% (n = 24/82). Through culture techniques, 16.7% (n = 4/24) of the cats that tested positive were carriers with positive kidney cultures, and one cat was culture positive for both urine and kidney. The Leptospira spp. isolates were identified as pathogenic L. interrogans serovar Bataviae through serological and molecular methods. Through serological techniques, 87.5% (n = 21/24) had positive antibody titers (100-1600) and most of the Bataviae serogroup (n = 19/21). Using PCR, 16.7% (n = 4/24) of cats were shown to have pathogenic Leptospira spp. DNA in their urine. Furthermore, three out of four culture positive cats were serology negative. The present study reports the first retrieval of pathogenic leptospires from urine and kidneys obtained from naturally infected cats. The results provide evidence of the potential role of naturally infected cats in the transmission of leptospires. Additionally, leptospiral infection occurs sub-clinically in cats. The culture isolation provides evidence that healthy cats could be reservoirs of leptospiral infection, and this information may promote the development of disease prevention strategies for the cat population.

Matched MeSH terms: Leptospira/isolation & purification*; Leptospira/physiology*
Pathogenic leptospiras isolated from Malaysian surface waters

Alexander AD, Evans LB, Baker MF, Baker HJ, Ellison D, Marriapan M

Appl Microbiol, 1975 Jan;29(1):30-3.
PMID: 1110490

Pathogenic leptospiras (1,424) isolated from natural waters and wet soils in Malaysia comprised 29 different serovars (synonym serotypes). All except two of the serovars had been found previously in Malaysia. The exceptional serovars were werrasingha, an Autumnalis serogroup member originally isolated in Ceylon, and a new serovar designated evansi. Serovar evansi had serological affinities with serovar ranarum which was isolated from the kidney of a frog in Iowa. The large variety of serovars found in jungle areas was consistent with similar previous findings of diverse serovar infections in troops who had operated in Malaysian jungles.

Matched MeSH terms: Leptospira/classification*; Leptospira/isolation & purification; Leptospira/pathogenicity
Fulltext Evaluation of a Commercial Immuno-Chromatographic Assay Kit for Rapid Detection of IgM Antibodies against Leptospira Antigen in Human Serum

Amran F, Liow YL, Halim NAN

J Korean Med Sci, 2018 Apr 23;33(17):e131.
PMID: 29686599 DOI: 10.3346/jkms.2018.33.e131

Leptospirosis is a febrile zoonotic disease. Routine diagnosis of leptospirosis is based on the detection of specific antibodies with serological tests. The aim of our study was to determine the usefulness of immunochromatographic assay (ICA), ImmuneMed Leptospira IgM Duo Rapid test kit from Korea, in rapid screening of acute leptospirosis in emergency cases with limited expertise. A total of 197 serum samples (93 positive, 104 negative) were selected randomly. The test has good diagnostic sensitivity 73% and specificity 90%. With positive predictive value of 87% and negative predictive value of 79%, this reassures patients have higher chance of correct diagnosis. This ICA is acceptable for screening of leptospirosis but confirmation with microscopic agglutination test should follow.

Matched MeSH terms: Leptospira
Draft Genome Sequence of Leptospira interrogans Serovar Bataviae Strain LepIMR 22 Isolated from a Rodent in Johor, Malaysia

Amran F, Mohd Khalid MK, Mohamad S, Mat Ripen A, Ahmad N, Goris MG, et al.

Genome Announc, 2016;4(5).
PMID: 27609924 DOI: 10.1128/genomeA.00956-16

Leptospira interrogans serovar Bataviae was recently identified as one of the persistent Leptospira serovars in Malaysia. Here, we report the draft genome sequence of the L. interrogans serovar Bataviae strain LepIMR 22 isolated from kidney of a rodent in Johor, Malaysia.

Matched MeSH terms: Leptospira; Leptospira interrogans
Fulltext Molecular Characterization of Leptospira spp. in Environmental Samples from North-Eastern Malaysia Revealed a Pathogenic Strain, Leptospira alstonii

Azali MA, Yean Yean C, Harun A, Aminuddin Baki NN, Ismail N

J Trop Med, 2016;2016:2060241.
PMID: 27127522 DOI: 10.1155/2016/2060241

The presence of pathogenic Leptospira spp. in the environment poses threats to human health. The aim of this study was to detect and characterize Leptospira spp. from environmental samples. A total of 144 samples comprised of 72 soil and 72 water samples were collected from markets and recreational areas in a north-eastern state in Malaysia. Samples were cultured on Ellinghausen and McCullough modified by Johnson and Harris media. Leptospires were positive in 22.9% (n = 33) of the isolates. Based on partial sequences of 16S rRNA, a pathogenic leptospire, Leptospira alstonii (n = 1/33), was identified in 3% of the isolates followed by intermediate leptospire (L. wolffii, n = 1/33, and L. licerasiae, n = 7/33) and nonpathogenic leptospire, L. meyeri (n = 22/33) in 24.2% and 66.7%, respectively. This study demonstrates the presence of a clinically significant pathogenic L. alstonii in the environments which could pose health risks to the occupants and visitors.

Matched MeSH terms: Leptospira
Fulltext Knowledge, attitude and practice about leptospirosis prevention among town service workers in northeastern Malaysia: a cross sectional study

Azfar ZM, Nazri SM, Rusli AM, Maizurah O, Zahiruddin WM, Azwany YN, et al.

J Prev Med Hyg, 2018 Mar;59(1):E92-E98.
PMID: 29938244 DOI: 10.15167/2421-4248/jpmh2018.59.1.776

INTRODUCTION: Many efforts have been done to reduce leptospirosis infections in Malaysia especially among high risk groups including town service workers. Town service workers are more likely to be exposed to the leptospiral infection resulting from their occupational activities.
METHODS: A cross sectional study was conducted in northeastern Malaysia involving 321 town service workers who were subjected to answer an interviewer-guided validated questionnaire which consists of sociodemographic, knowledge, attitude and practice information. Data were entered and analyzed using SPSS Version 20.
RESULTS: All of the respondents were Malay with mean (SD) age of 40.6 (10.28) years old. The mean (SD) duration of employment was 12.1 (9.62) years. Fifty four respondents (16.8%) had never heard of leptospirosis. Among the respondents, 215 (67.0%) of them had poor knowledge on leptospirosis. Meanwhile, 167 (52.0%) and only 128 (39.9%) of them had satisfactory attitude and practice respectively. It was found that knowledge on risk factors for leptospirosis was lacking. There were high risk attitudes such as drinking habit and protective equipment used during working with the favourable answers ranged from 67.3% to 89.1%. The weakest area identified in their practice was also on the use of protective equipment.
CONCLUSIONS: The workers' level of knowledge and practice were relatively poor despite an overall good practice on leptospirosis. This finding might expose them to an increased risk of contracting leptospirosis. Identified weak areas in their knowledge, attitude and practice will assist the policy makers to develop a focused and well-directed intervention program on leptospirosis infection.

Matched MeSH terms: Leptospira/isolation & purification
Molecular characterization of pathogenic Leptospira sp. in small mammals captured from the human leptospirosis suspected areas of Selangor state, Malaysia

Azhari NN, Ramli SNA, Joseph N, Philip N, Mustapha NF, Ishak SN, et al.

Acta Trop, 2018 Dec;188:68-77.
PMID: 30145261 DOI: 10.1016/j.actatropica.2018.08.020

Leptospirosis is caused by the spirochetal bacterium Leptospira of which rodents are considered the most important reservoir. This study aims to determine and characterize virulent Leptospira species among rodents and small mammals found in human settlements and recreational spots within the Hulu Langat and Gombak districts of Selangor, Malaysia; regions that frequently report probable human leptospirosis cases. Molecular analysis revealed an overall Leptospira detection rate of 14.3% among the 266 small mammals captured, and the human settlements were found to have the highest number of isolates (15.1%), followed by recreational sites (14.5%). The molecular characterization conducted based on the lipL32, secY genes and MLST revealed that the strains belonged to four different species, including; Leptospira interrogans (29; 76.3%; ST50, ST238, ST243), L. kirschneri (5; 13.15%; ST110), L. borgpetersenii (3; 8%; ST143) and L. weilii (1; 2.63%; ST242). The study revealed genotypes of circulating strains among small mammals in Malaysia, which include Leptospira locus ST110 L. kirschneri, ST 50 L. interrogans, ST143 L. borgpetersenii and ST242 L. weilii. Among the small mammals studied, 17/105 (16.2%) Rattus norvegicus, 7/59 (11.9%) of Rattus rattus, 5/24 (20.8%) of Maxomys whiteheadi, 4/18 (22.2%) of Sundamys muelleri, 2/22 (9%), Tupaia gliss, 2/16 (12.5%) Rattus tiomanicus and 1/4 (25%) of Suncus murinus carried pathogenic leptospires. The data from the present study may imply that, in addition to rodents, other small mammals also serve as maintenance hosts for Leptospira. Hence, much remains unknown about Leptospira maintenance hosts, and there is need for further investigation to ascertain the prevailing serovars of pathogenic Leptospira in Malaysia. This will assist in the development of efficient diagnostic assays with improved microscopic agglutination test (MAT) panels, and in the implementation of suitable prevention and control measures.

Matched MeSH terms: Leptospira/genetics*; Leptospira/isolation & purification
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; Leptospira/isolation & purification*; Leptospira interrogans/isolation & purification; Leptospira interrogans serovar canicola/isolation & purification
Leptospira interrogans serovar unipertama isolated in Malaysia

Bahaman AR, Ibrahim AL, Stallman ND

Int. J. Syst. Bacteriol., 1990 Jan;40(1):98-9.
PMID: 2223603

A leptospiral isolate from a bovine kidney was found to be antigenically different from all previously recognized serovars of Leptospira interrogans based on the cross-agglutinin absorption test. The new serovar belongs to the Sejroe serogroup, and the name Leptospira interrogans serovar unipertama is proposed for it, with strain K2-1 as the reference strain.

Matched MeSH terms: Leptospira/classification*; Leptospira/isolation & purification
Serological prevalence of leptospiral infection in domestic animals in West Malaysia

Bahaman AR, Ibrahim AL, Adam H

Epidemiol Infect, 1987 Oct;99(2):379-92.
PMID: 3678399

A cross-sectional serological survey of domestic animals in West Malaysia revealed that 25.5% of the animals examined had agglutinating antibodies to one or more antigens belonging to Leptospira interrogans. Significant prevalence of infection was observed in cattle (40.5%), buffaloes (31%) and pigs (16%). The Sejroe serogroup was shown to be the principal one involved in cattle and buffaloes, and to a lesser extent the Tarassovi and Pomona serogroups. Evidence of infection in domestic animals by strains bearing the other seven antigens appeared insignificant and was indicative of sporadic infection. A majority of the large (semi-intensive) cattle and buffalo farms demonstrated a high prevalence of leptospiral infection. In both species of domestic animals mentioned above, the prevalence of infection was significantly higher (P = 0.01) in the semi-intensive farms than in the smallholdings. Amongst cattle, the droughtmasters had the highest prevalence whilst the Kedah-Kelantan (an indigenous breed) had the lowest prevalence of leptospiral infection. In general, the temperate breeds of cattle had a significantly (P = 0.01) higher prevalence of infection than local breeds. Leptospiral infection in goats and sheep was shown to be sporadic, and the Pomona serogroup was the principal leptospiral serogroup involved in these small ruminants. The prevalence of infection in pigs was observed to decline during the study period, and it is suspected that pigs in West Malaysia are the maintenance host for serovar pomona whilst cattle are the maintenance host for serovar hardjo. Overall, it appears that domestic animals in Malaysia will play a bigger role in the epidemiology of leptospiral infection with the advent of sophisticated farming.

Matched MeSH terms: Leptospira interrogans/immunology
Fulltext A review of leptospirosis in Malaysia

Bahaman AR, Ibrahim AL

Vet Res Commun, 1988;12(2-3):179-89.
PMID: 3055663 DOI: 10.1007/BF00362799

This paper reviews the literature on leptospirosis in Malaysia from its first description in 1928 until the present day. Most of the early reports were on investigations of leptospirosis in wildlife and man and up-to-date, thirty-seven leptospiral serovars from thirteen serogroups have been bacteriologically identified. The thirteen serogroups are: Australis, Autumnalis Bataviae, Canicola, Celledoni, Grippotyphosa, Hebdomadis, Icterohaemorrhagiae, Javanica, Pomona, Pyrogenes, Sejroe and Tarassovi. Rats have been ascribed as the principal maintenance host of leptospires in Malaysia. However, serovars from the Pomona, Pyrogenes and Sejroe serogroups have yet to be isolated from rats. It is considered that the majority of leptospirosis cases in man were due to association of man with an environment where rats were plentiful. Recent investigations on domestic animals disclosed a high prevalence of infection in cattle and pigs and they were suspected as being the maintenance host for serovar hardjo and pomona respectively. There is ample scope for research in leptospirosis, particularly in the epidemiology and control of the disease in domestic animals. The strategy to control the infection in domestic animals and man in Malaysia is bound to be different from that of the temperate countries, basically due to the presence of a large number of leptospiral serovars in wildlife, further confounded by geographical and financial constraints.

Matched MeSH terms: Leptospira/classification; Leptospira/isolation & purification
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; Leptospira/isolation & purification; Leptospira interrogans serovar canicola/immunology; Leptospira interrogans serovar canicola/isolation & purification
Fulltext Vascular pathology associated with Leptospira icterohaemorrhagiae serovar Lai strain Langkawi infection in guinea pigs (Cavia porcellus)

Bahaman, A.R., Fuzina, N.H., Tengku-Azmi, T.I., Tyagita, G.H., Jasni, S.

Jurnal Veterinar Malaysia, 2018;30(1):7-14.
MyJurnal

Fifteen (15) guinea pigs were experimentally infected with Leptospira icterohemorrhagiae serovar Lai strain
Langkawi, a new strain that was isolated from a human leptospirosis patient. Hematoxylin and Eosin ((H&E) staining
showed haemorrhages, congestion and oedema in all internal organs examined (lungs, liver, spleen and kidneys) with
inflammatory cell infiltration characterized by neutrophils, lymphocytes and macrophages. Hydropic degeneration and
cell necrosis were also common in our findings. Leptospires were detected starting Day 2 p.i by silver staining and
Transmission Electron Microscopy (TEM). Rise in antibody titres started on Day 5 p.i and leptospiral DNA was
detected beginning Day 3 in the kidneys and Day 5 in the liver by Polymerase Chain Reaction (PCR) assay. The
findings illustrated the pathogenesis of leptospirosis in guinea pigs which disclosed them as a suitable animal model for
demonstration of clinical symptoms of leptospirosis and pathological changes after being infected with Leptospira
icterohaemorrhagiae serovar Lai strain Langkawi, particularly pulmonary haemorrhages, a leading cause of mortality
in human leptospirosis.

Matched MeSH terms: Leptospira; Leptospira interrogans serovar icterohaemorrhagiae
Pathogenic Leptospira in Malaysian surface waters. I. A method of survey for Leptospira in natural waters and soils

Baker MF, Baker HJ

Am J Trop Med Hyg, 1970 May;19(3):485-92.
PMID: 5446317
Matched MeSH terms: Leptospira/pathogenicity*
Fulltext Advances & challenges in leptospiral vaccine development

Bashiru G, Bahaman AR

Indian J Med Res, 2018 Jan;147(1):15-22.
PMID: 29749356 DOI: 10.4103/ijmr.IJMR_1022_16

Considerable progress has been made in the field of leptospiral vaccines development since its first use as a killed vaccine in guinea pigs. Despite the fact that the immunity conferred is restricted to serovars with closely related lipopolysaccharide antigen, certain vaccines have remained useful, especially in endemic regions, for the protection of high-risk individuals. Other conventional vaccines such as the live-attenuated vaccine and lipopolysaccharide (LPS) vaccine have not gained popularity due to the reactive response that follows their administration and the lack of understanding of the pathogenesis of leptospirosis. With the recent breakthrough and availability of complete genome sequences of Leptospira, development of novel vaccine including recombinant protein vaccine using reverse vaccinology approaches has yielded encouraging results. However, factors hindering the development of effective leptospiral vaccines include variation in serovar distribution from region to region, establishment of renal carrier status following vaccination and determination of the dose and endpoint titres acceptable as definitive indicators of protective immunity. In this review, advancements and progress made in LPS-based vaccines, killed- and live-attenuated vaccines, recombinant peptide vaccines and DNA vaccines against leptospirosis are highlighted.

Matched MeSH terms: Leptospira
Fulltext Isolation and molecular characterization of Leptospira interrogans and Leptospira borgpetersenii isolates from the urban rat populations of Kuala Lumpur, Malaysia

Benacer D, Mohd Zain SN, Amran F, Galloway RL, Thong KL

Am J Trop Med Hyg, 2013 Apr;88(4):704-9.
PMID: 23358635 DOI: 10.4269/ajtmh.12-0662

Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.

Matched MeSH terms: Leptospira interrogans/classification; Leptospira interrogans/genetics; Leptospira interrogans/isolation & purification*

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