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1. Introduction
Leptospirosis-a neglected zoonotic disease caused by pathogenic Leptospira strains-is now becoming a global threat for causing significant morbidity and mortality in humans in both rural and urban settings worldwide [1,2,3,4,5]. Recently, more than 300 serovars and 20 species of these pathogenic strains have been identified and mammals, including rodents, are among the important reservoirs known to harbor these spirochetes [6,7,8]. Human leptospirosis is acquired through direct or indirect contact with water or soil contaminated by the urine, blood or tissues of infected mammals [3,9]. The disease has a wide clinical spectrum ranging from asymptomatic to hemorrhagic phenomenon and even death [2]. Nonetheless, the clinical manifestations of human leptospirosis possess a significant challenge to clinicians in managing the disease, since other tropical diseases such as dengue and malaria rather share similar symptomatology and epidemiology, albeit the pathogenesis pathways are different [10,11].
Globally, leptospirosis is considered as a re-emerging infectious disease and more than one million cases have been reported every year with the estimated incidence of 0.1 to 975 cases per 100,000 population annually [1,12]. The disease burden is largely centered in tropical and subtropical regions such as Southeast Asia and also in Central and South America regions [13,14,15,16]. Several contributing factors have been highlighted for high morbidity and mortality rates in these regions. The geographical location with frequent rainfall and floods, climate change, high number of animal reservoirs, human activities and other socio-epidemiological influences are attributable to the high incidence of leptospirosis [13,17,18,19,20].
Several outbreaks have been reported following climate change and human activities in Malaysia. For instance, an Eco-Challenge held in Borneo Island has recorded 29 of 304 athletes from 26 countries contracted leptospirosis [21]. Another outbreak has been reported involving 46 boys and young adults aged 8 to 19 years old who swam in a creek in Sabah with one succumbed to leptospirosis [22]. As for the natural disasters, 20 human leptospirosis cases with two deaths were reported following the prolonged flood during monsoon season that hit Johor, Malaysia [23]. Recently, a few north-eastern states of Malaysia such as Kelantan and Selangor recorded a high number of human leptospirosis cases in 2014 due to flood as well [24].
With the wealth of scientific data, our understanding of leptospirosis in Malaysia seems...