Leptospira interrogans and Leptospira kirschneriare the dominant Leptospira species causing human leptospirosis in Central Malaysia.

Noraini Philip,Muhamad Yazli Yuhana,Siti Norbaya Masri,Leslie Thian Lung Than,Muhamad Arif,Mithra Seganathirajah,Elanngovan Nagandran,Siti Nur Alia Ramli,Norliza Bahtiar Affendy,Pappitha Raja,Pukunan Renganathan,Niazlin Mohd Taib,Zamberi Sekawi,Vasantha Kumari Neela,Cyrille Goarant,Marga G A Goris

doi:10.1371/journal.pntd.0008197

Abstract

BackgroundLeptospirosis, 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 findingsWe 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/SignificanceLeptospira 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.

Highlights

Leptospirosis is a worldwide, life-threatening zoonotic disease that accounts for an estimated 58,900 deaths and more than one million cases annually [1,2]
Leptospirosis is a zoonotic disease caused by pathogenic Leptospira species
The genus Leptospira contains 64 species isolated from human, animals and environments

Summary

Introduction

Leptospirosis is a worldwide, life-threatening zoonotic disease that accounts for an estimated 58,900 deaths and more than one million cases annually [1,2]. MAT is the gold standard for serological diagnosis of leptospirosis yet has low sensitivity in the early course of infection, as the level of detectable IgM and IgG antibodies are low during this phase [6]. It requires a high level of technical expertise and the maintenance of a large panel of live pathogenic Leptospira representing both international and local serovars. Identification of infecting Leptospira species mainly in clinical specimens is important to determine the clinical significance, the probable source of infection and to distinguish sporadic cases from possible outbreaks. 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

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