Leptospirosis is a naturally occurring pathogen in Singapore. It is caused by bacteria that is transmitted from animals (e.g. rodents and dogs) to humans through direct contact of the skin (especially if broken) or mucous membranes (e.g. mouth, nose, eyes) with the urine of infected animals. Contact with contaminated soil, water or vegetation may also cause infection. From 2012 till end 2017, there have been 289 documented cases of leptospirosis, of which nine were SAF servicemen. For public health reasons, leptospirosis was gazetted by the Ministry of Health as a notifiable disease in Sep 2016. 

3SG Nigel Loh Kai Wen, a full-time national serviceman, contracted leptospirosis and passed away at Changi General Hospital on 24 May 2017. A comprehensive investigation was conducted to determine the possible sources of infection. This included environmental audits and sampling of 3SG Loh's working environment to determine the epidemiological and clinical details, possible source and mode of transmission of the infection. No causative agent and no rodent activities were detected in his camp. There were also no other cases of leptospirosis reported among his platoon or company soldiers. It was concluded that 3SG Loh's leptospirosis was not acquired during SAF training.

Although 3SG Loh's death was not due to training, MINDEF provided financial support, including a Benevolent Grant, to assist with the family's financial needs following the death.