An outbreak of leptospirosis among reserve military recruits, Hulu Perdik, Malaysia

Abstract

Here, we investigated an outbreak of leptospirosis among reserve military recruits that occurred following a survival exercise in the Hulu Perdik forest within the Hulu Langat district, Kuala Lumpur, Malaysia. Blood samples from the 12 patients that presented symptoms for febrile illness on clinical examination were subjected to laboratory investigation, comprising Lepto IgM rapid test, IgM ELISA, and microscopic agglutination test (MAT). All these patients were interviewed for possible risk factors for leptospirosis. Rodent trapping and environmental sampling for possible isolation of leptospires in the outbreak site was performed. The isolated leptospires were genetically characterized and investigated for the potential epidemiological link with human leptospirosis. Among the 12 patients, two (2/12; 16.6%) were confirmed positive for leptospirosis by microscopic agglutination test (MAT with titers 400-800; serovar autumnalis and hardjobovis). Two Leptospira species from rodents (L. interrogans and L. borgpetersenii) and two from the environment (L. kmetyi and L. wolffii) were identified. The possible epidemiological link between human serovars and animal Leptospira species indicates rodents as the potential reservoir while the environment (soil and water) serves as a transmission route. This investigation highlights the robust presence of pathogenic leptospires on Malaysian environment and rodents which may present the risk of infection, especially among high-risk individuals. Hence, occupational risk individuals are cautioned to observe appropriate preventive measures including prophylaxis and seek immediate medical attention for any illness following similar activities.

Leptospira interrogans and Leptospira kirschneri are the dominant Leptospira species causing human leptospirosis in Central Malaysia

“…Although leptospirosis can affect all age groups and both genders, active involvement in outdoor activities increases its incidence in adults and males. More than half (54.3%) of the patients had a history of contact with rats indicating that exposure to rats increases their risk of getting the disease [30]. Secondly, we found outdoor activities as the major risk factor which is in agreement with our earlier finding and also elsewhere [30][31][32][33].…”

“…All three species have been previously isolated and identified from humans, animals or the environment in Malaysia. L. kirschneri and L. interrogans, the most common and widely distributed Leptospira species from rodents and small mammals [13,30,[47][48][49][50][51] were identified as the main human-infecting Leptospira species in Malaysia based on our study. L. wolffii, an intermediate species was detected in the blood of two patients.…”

High incidence of asymptomatic leptospirosis among urban sanitation workers from Kota Kinabalu, Sabah, Malaysian Borneo

“…Therefore, determining the types of Leptospira present in a given area could have great public health, diagnostic, and epidemiological implications. Over 200 Leptospira serovars have been identified in Malaysia, mostly in rodents, thereby making them the most important sources of human infections and environmental contamination 34 . In Malaysia, various serovars have been detected in different areas.…”

Leptospirosis and Coinfection: Should We Be Concerned?

“…Direct contact with water, soil and vegetation contaminated with of 16 pathogenic leptospires during water-related incidence has been widely documented as the risk factor for leptospirosis [8][9][10]. Occupational activities that place individuals at high risk of infection include farming, agriculture, mining, sewage maintenance, and military action [11][12][13][14][15].…”