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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 Retrospective Study of Leptospirosis in Malaysia

Garba B, Bahaman AR, Khairani-Bejo S, Zakaria Z, Mutalib AR

Ecohealth, 2017 Jun;14(2):389-398.
PMID: 28405850 DOI: 10.1007/s10393-017-1234-0

Leptospirosis is a bacterial disease transmitted to humans and animals by direct or indirect contact with urine or body fluids from infected animals especially rodents. Infection can be associated with wide clinical spectrum varying from asymptomatic to severe multi-organ syndrome with life-threatening consequences. We conducted a review of published studies on incidences, case reports, sero-epidemiological surveys from year 2000 to 2015 using different electronic data bases. Our study revealed that majority of the studies were conducted in Peninsular Malaysia and predominantly among high-risk human groups. Most of the studies on domestic animals were conducted in the 1980s; hence, the current status of leptospirosis among domestic animal population remains largely unknown. There tend to be a sharp rise in incidence rate among human population in the year 2014 which was attributed to flooding and heavy rainfall experienced as well as recreational activities. Several gaps in epidemiological knowledge were also disclosed.

Matched MeSH terms: Leptospira/pathogenicity
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/pathogenicity
Fulltext High incidence of asymptomatic leptospirosis among urban sanitation workers from Kota Kinabalu, Sabah, Malaysian Borneo

Jeffree MS, Mori D, Yusof NA, Atil AB, Lukman KA, Othman R, et al.

Sci Rep, 2020 11 10;10(1):19442.
PMID: 33173153 DOI: 10.1038/s41598-020-76595-0

Leptospirosis is a public health challenge in Sabah State of Malaysian Borneo. Rapid urbanization, rural-to-urban migration, and undocumented immigration in Sabah have increased the pressure on the urban garbage disposal system. Rodents and other small animals thrive under these conditions. We hypothesized that urban sanitation workers would be at risk of developing leptospirosis. In total, 303 urban sanitation workers with a mean age of 42.6 years were enrolled in this study. The serum samples collected from these workers were subjected to the microscopic agglutination test (MAT), PCR and nucleotide sequencing of the amplicons to confirm the presence of Leptospira. The phylogenetic analysis using the neighbor joining method was performed to assess whether they were pathogenic. In this study 43.8% (133/303) of the samples were MAT-seropositive and among them, 29 (21.8%) were positive by PCR. Nucleotide sequencing of the amplicons confirmed the presence of Leptospira. Phylogenetic analysis showed that our strains belonged to the pathogenic group of Leptospira. A high proportion of urban sanitation workers were seropositive for leptospirosis, and a considerable number were PCR positive for Leptospira, thereby indicating asymptomatic infections. Further research is needed to confirm whether this is a transient phenomenon or antibiotic therapy is required.

Matched MeSH terms: Leptospira/pathogenicity
Fulltext Leptospirosis and Workplace Environmental Risk Factors among Cattle Farmers in Northeastern Malaysia

Daud AB, Mohd Fuzi NMH, Wan Mohammad WMZ, Amran F, Ismail N, Arshad MM, et al.

Int J Occup Environ Med, 2018 04;9(2):88-96.
PMID: 29667646 DOI: 10.15171/ijoem.2018.1164

BACKGROUND: Leptospirosis is an emerging zoonosis and its occurrence has been reported to be rising globally. The environment plays an important role in the survival of Leptospira and determines the risk of infection. Those who were exposed to and had contact with contaminated environment through their occupational, recreational and other activities can be infected with the organism.
OBJECTIVE: To determine the seroprevalence of leptospirosis among cattle farmers, prevalence of pathogenic Leptospira, and the workplace environmental risk factors for leptospirosis among cattle farmers in northeastern Malaysia.
METHODS: A cross-sectional study involving 120 cattle farmers was conducted. The participants answered an interviewer-guided questionnaire that consisted of sociodemographic and workplace environment characteristics questionnaire, before having their blood sample taken for microscopic agglutination test (MAT). Seropositivity was determined using a cut-off titer of ≥1:100. 248 environmental samples were also collected from the cattle farms for polymerase chain reaction (PCR).
RESULTS: The overall seroprevalence of leptospiral antibodies was 72.5% (95% CI 63.5% to 80.1%) and the prevalence of pathogenic Leptospira in the cattle farms environment was 12.1% (95% CI 8.4% to 17.0%). The independent factors associated with seropositivity of leptospirosis among cattle farmers were positive pathogenic Leptospira in the environment (Adj OR 5.90, 95% CI 1.34 to 26.01) and presence of garbage dumping in the farm (Adj OR 2.40, 95% CI 1.02 to 5.65).
CONCLUSION: Preventing leptospirosis incidence among cattle farmers necessitates changes in work environment. Identifying modifiable factors may also contribute to the reduction of infection.

Matched MeSH terms: Leptospira/pathogenicity*
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/pathogenicity
Fulltext Revisiting the taxonomy and evolution of pathogenicity of the genus Leptospira through the prism of genomics

Vincent AT, Schiettekatte O, Goarant C, Neela VK, Bernet E, Thibeaux R, et al.

PLoS Negl Trop Dis, 2019 May;13(5):e0007270.
PMID: 31120895 DOI: 10.1371/journal.pntd.0007270

The causative agents of leptospirosis are responsible for an emerging zoonotic disease worldwide. One of the major routes of transmission for leptospirosis is the natural environment contaminated with the urine of a wide range of reservoir animals. Soils and surface waters also host a high diversity of non-pathogenic Leptospira and species for which the virulence status is not clearly established. The genus Leptospira is currently divided into 35 species classified into three phylogenetic clusters, which supposedly correlate with the virulence of the bacteria. In this study, a total of 90 Leptospira strains isolated from different environments worldwide including Japan, Malaysia, New Caledonia, Algeria, mainland France, and the island of Mayotte in the Indian Ocean were sequenced. A comparison of average nucleotide identity (ANI) values of genomes of the 90 isolates and representative genomes of known species revealed 30 new Leptospira species. These data also supported the existence of two clades and 4 subclades. To avoid classification that strongly implies assumption on the virulence status of the lineages, we called them P1, P2, S1, S2. One of these subclades has not yet been described and is composed of Leptospira idonii and 4 novel species that are phylogenetically related to the saprophytes. We then investigated genome diversity and evolutionary relationships among members of the genus Leptospira by studying the pangenome and core gene sets. Our data enable the identification of genome features, genes and domains that are important for each subclade, thereby laying the foundation for refining the classification of this complex bacterial genus. We also shed light on atypical genomic features of a group of species that includes the species often associated with human infection, suggesting a specific and ongoing evolution of this group of species that will require more attention. In conclusion, we have uncovered a massive species diversity and revealed a novel subclade in environmental samples collected worldwide and we have redefined the classification of species in the genus. The implication of several new potentially infectious Leptospira species for human and animal health remains to be determined but our data also provide new insights into the emergence of virulence in the pathogenic species.

Matched MeSH terms: Leptospira/pathogenicity*
Fulltext Isolation of Leptospira kmetyi from residential areas of patients with leptospirosis in Kelantan, Malaysia

Mohd Ali MR, Mohamad Safiee AW, Yusof NY, Fauzi MH, Yean Yean C, Ismail N

J Infect Public Health, 2017 12 23;11(4):578-580.
PMID: 29277333 DOI: 10.1016/j.jiph.2017.12.008

BACKGROUND: Environmental sampling provides important information that enhances the understanding of the leptospiral human-environment-animal relationship. Several studies have described the distribution of Leptospira in the environment. However, more targeted sites, that is, areas surrounding leptospirosis patients' houses, remain under-explored. Therefore, this study aims to detect the presence of Leptospira spp. in the residential areas of patients with leptospirosis.
METHODS: Soil and water samples near leptospirosis patients' residences were collected, processed and cultured into EMJH media. Partial 16S rRNA gene sequencing was performed to confirm the identity of Leptospira.
RESULTS: EMJH culture and partial 16S rRNA gene sequencing revealed predominant growth of pathogenic Leptospira kmetyi (17%, n=7/42). All tested locations had at least one Leptospira sp., mostly from the soil samples.
CONCLUSION: More than one species of Leptospira may be present in a sampling area. The most common environmental isolates were pathogenic L. kmetyi.

Matched MeSH terms: Leptospira/pathogenicity
Pathogenic and saprophytic Leptospira species in water and soils from selected urban sites in peninsular Malaysia

Benacer D, Woh PY, Mohd Zain SN, Amran F, Thong KL

Microbes Environ, 2013;28(1):135-40.
PMID: 23363618

Leptospira species were studied in water and soils from selected urban sites in Malaysia. A total of 151 water (n=121) and soil (n=30) samples were collected from 12 recreational lakes and wet markets. All samples were filtered and inoculated into semi-solid Ellinghausen and McCullough modified by Johnson and Harris (EMJH) media supplemented with additional 5-fluorouracil. The cultures were then incubated at 30°C and observed under a dark field microscope with intervals of 10 days. A PCR assay targeting the rrs gene was used to confirm the genus Leptospira among the isolates. Subsequently, the pathogenic status of the isolates was determined using primer sets G1/G2 and Sapro1/Sapro2, which target the secY and rrs genes, respectively. The isolates were identified at serogroup level using the microscopic agglutination test (MAT) while their genetic diversity was assessed by pulsed field gel electrophoresis (PFGE). Based on dark field microscopy, 23.1% (28/121) water and 23.3% (7/30) soil cultures were positive for Leptospira spp. Of the 35 positive cultures, only 8 were pure and confirmed as Leptospira genus by PCR assay. Two out of 8 isolates were confirmed as pathogenic, 5 were saprophytic and one was intermediate. These 8 isolates were negative for the 25 reference hyperimmune rabbit sera tested in the MAT. PFGE showed that all 8 of these environmental Leptospira spp. were genetically diverse. In conclusion, the presence of pathogenic Leptospira spp. in the urban Malaysian environment may indicate and highlight the importance of water screening, especially in recreational lakes, in order to minimize any chance of Leptospira infection.

Matched MeSH terms: Leptospira/pathogenicity
Fulltext Knowledge, Attitude, and Practices regarding Leptospirosis among Visitors to a Recreational Forest in Malaysia

Shafie NJ, Abdul Halim NS, Nor Zalipah M, Mohd Amin NAZ, Syed Esa SM, Md-Nor S, et al.

Am J Trop Med Hyg, 2021 Jan 18;104(4):1290-1296.
PMID: 33534768 DOI: 10.4269/ajtmh.20-0306

Leptospirosis is a zoonotic disease and a worldwide public health problem that affects mainly high-risk groups. Characterizing knowledge, attitude, and practice (KAP) among high-risk groups is important to develop appropriate prevention programs. Here, we performed a cross-sectional study among 300 visitors of a recreational forest in Malaysia to examine leptospirosis KAP and demographics. These variables were integrated to create knowledge and practice scores for each respondent. All respondents had heard about leptospirosis, and 87% of them correctly identified it as a disease. The majority of respondents had high knowledge (63%), positive attitude, and good practice (68%) toward prevention of the disease. However, there were gaps in knowledge, with 78% of the respondents indicating eating without washing hands as the major cause of leptospirosis transmission. Our final model identified that higher knowledge score was associated with higher practice score. Our results indicate that it is important to increase knowledge, especially on transmission routes of leptospirosis, among visitors in recreational areas. Moreover, more attention needs to be paid to promote good practice habits among visitors, targeting those at higher risk of being infected by leptospirosis to prevent potential outbreaks in the recreational areas.

Matched MeSH terms: Leptospira/pathogenicity
Fulltext Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland

Nally JE, Arent Z, Bayles DO, Hornsby RL, Gilmore C, Regan S, et al.

PLoS Negl Trop Dis, 2016 12;10(12):e0005174.
PMID: 27935961 DOI: 10.1371/journal.pntd.0005174

The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira.

Matched MeSH terms: Leptospira/pathogenicity
Fulltext Leptospira interrogans and Leptospira kirschneri are the dominant Leptospira species causing human leptospirosis in Central Malaysia

Philip N, Bahtiar Affendy N, Ramli SNA, Arif M, Raja P, Nagandran E, et al.

PLoS Negl Trop Dis, 2020 Mar;14(3):e0008197.
PMID: 32203511 DOI: 10.1371/journal.pntd.0008197

BACKGROUND: Leptospirosis, commonly known as rat-urine disease, is a global but endemic zoonotic disease in the tropics. Despite the historical report of leptospirosis in Malaysia, the information on human-infecting species is limited. Determining the circulating species is important to understand its epidemiology, thereby to strategize appropriate control measures through public health interventions, diagnostics, therapeutics and vaccine development.
METHODOLOGY/PRINCIPLE FINDINGS: We investigated the human-infecting Leptospira species in blood and serum samples collected from clinically suspected leptospirosis patients admitted to three tertiary care hospitals in Malaysia. From a total of 165 patients, 92 (56%) were confirmed cases of leptospirosis through Microscopic Agglutination Test (MAT) (n = 43; 47%), Polymerase Chain Reaction (PCR) (n = 63; 68%) or both MAT and PCR (n = 14; 15%). The infecting Leptospira spp., determined by partial 16S rDNA (rrs) gene sequencing revealed two pathogenic species namely Leptospira interrogans (n = 44, 70%) and Leptospira kirschneri (n = 17, 27%) and one intermediate species Leptospira wolffii (n = 2, 3%). Multilocus sequence typing (MLST) identified an isolate of L. interrogans as a novel sequence type (ST 265), suggesting that this human-infecting strain has a unique genetic profile different from similar species isolated from rodents so far.
CONCLUSIONS/SIGNIFICANCE: Leptospira interrogans and Leptospira kirschneri were identified as the dominant Leptospira species causing human leptospirosis in Central Malaysia. The existence of novel clinically important ST 265 (infecting human), that is different from rodent L. interrogans strains cautions reservoir(s) of these Leptospira lineages are yet to be identified.

Matched MeSH terms: Leptospira/pathogenicity

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