Abstract
BackgroundAlthough Southeast Asia is one of the most leptospirosis afflicted regions, little is known about the diversity and molecular epidemiology of the causative agents of this widespread and emerging zoonotic disease.Methodology/Principal findingsWe used whole genome sequencing to examine genetic variation in 75 Leptospira strains isolated from patients in the Lao PDR (Laos) between 2006 and 2017.Eleven serogroups from 4 Leptospira species and 43 cgMLST-defined clonal groups (CGs) were identified. The most prevalent CG was CG272 (n = 18, 26.8%), composed of L. interrogans serogroup Autumnalis isolates. This genotype was recovered throughout the 12-year period and was associated with deaths, and with a large outbreak in neighbouring Thailand. Genome analysis reveals that the CG272 strains form a highly clonal group of strains that have, for yet unknown reasons, recently spread in Laos and Thailand. Additionally, accessory genes clearly discriminate CG272 strains from the other Leptospira strains.Conclusions/SignificanceThe present study reveals a high diversity of Leptospira genotypes in Laos, thus extending our current knowledge of the pan- and core-genomes of these life-threatening pathogens. Our results demonstrate that the CG272 strains belong to a unique clonal group, which probably evolved through clonal expansion following niche adaptation. Additional epidemiological studies are required to better evaluate the spread of this genotype in Southeast Asia. To further investigate the key factors driving the virulence and spread of these pathogens, more intense genomic surveillance is needed, combining detailed clinical and epidemiological data.
Highlights
It is estimated that one million patients suffer severe leptospirosis each year with nearly 60,000 deaths, mostly in developing tropical countries [1]
Pathogenic Leptospira are the causative agents for leptospirosis, a neglected and emerging zoonosis occurring worldwide
We investigated the genetic diversity of Leptospira strains isolated from patients over a 12-year period in Lao PDR
Summary
It is estimated that one million patients suffer severe leptospirosis each year with nearly 60,000 deaths, mostly in developing tropical countries [1]. The global burden of leptospirosis in terms of disability-adjusted life years (DALYs) is in the same range or even higher than for dengue, rabies, schistosomiasis, leishmaniasis and lymphatic filariasis [2]. It is very likely underestimated because of misdiagnosis and inadequate surveillance systems in place in most countries, where other diseases with similar non-specific presentations, such as dengue and malaria, are prevalent. Pathogenic Leptospira colonize the proximal renal tubules of reservoir hosts and are excreted through urine into the environment. Infections usually occur through contact with water or soil contaminated with the urine of infected animals. Southeast Asia is one of the most leptospirosis afflicted regions, little is known about the diversity and molecular epidemiology of the causative agents of this widespread and emerging zoonotic disease
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
