Leptospirosis: an under-recognised disease in the Pacific

Leptospirosis is a highly prevalent yet under-recognised disease. This zoonotic disease is particularly problematic in developing nations as its incidence increases across the globe (1). The Leptospira bacteria colonise the kidneys of the carrying animals, such as rodents and livestock. Bacteria are then released into the environment through the urine of the host animal (2). Therefore, any contact with either the animal or soil and water contaminated by its urine can result in infection transfer.

One of the reasons the disease is under-recognised is that it can be difficult to diagnose. The symptoms are particularly variable, ranging from very mild to life-threatening (1). Leptospirosis is classically described as a biphasic illness where, after an initial sudden onset of febrile illness, there is a period of mildly symptomatic disease for 10-20 days, before the fever returns. Importantly, the infection causes approximately 60 000 deaths per year around the world, and many more are affected by severe illness (3).

Leptospirosis is particularly problematic in tropical regions, including the Pacific, as the climate is ideal for bacterial survival (4). Outbreaks of the disease are typically linked with climate-related changes, such as flooding or extreme events (4). In Fiji, being of iTaukei ethnicity was found to be a significant risk factor for leptospirosis, as was living in villages or regions without treated water, or close proximity to livestock (5).

Leptospirosis is relatively manageable with antibiotic therapy, although its effectiveness has been brought into question (1). As with many infectious diseases, appropriate hygiene and access to clean water are important factors in mitigating disease transfer, and it is more important to prevent the disease from occurring, particularly in developing nations. Whilst climate-based risks for leptospirosis are unavoidable, such as flooding and natural disaster, raised awareness for the zoonotic disease can assist in reducing transmission in trying times.

Ultimately, leptospirosis is an important infectious disease in Pacific Island Countries and Territories, as it has the potential to lead to significant mortality. Whilst the region is predisposed to Leptospira proliferation due to climate-based factors, addressing modifiable risks for leptospirosis can reduce the impact of the disease.

1.              Bharti AR, Nally JE, Ricaldi JN, Matthias MA, Diaz MM, Lovett MA, et al. Leptospirosis: a zoonotic disease of global importance. The Lancet infectious diseases. 2003;3(12):757-71.

2.              Adler B, de la Peña Moctezuma A. Leptospira and leptospirosis. Vet Microbiol. 2010;140(3-4):287-96.

3.              Costa F, Hagan JE, Calcagno J, Kane M, Torgerson P, Martinez-Silveira MS, et al. Global morbidity and mortality of leptospirosis: a systematic review. PLoS Negl Trop Dis. 2015;9(9):e0003898.

4.              Lau CL, Smythe LD, Craig SB, Weinstein P. Climate change, flooding, urbanisation and leptospirosis: fuelling the fire? Trans R Soc Trop Med Hyg. 2010;104(10):631-8.

5.              Lau CL, Watson CH, Lowry JH, David MC, Craig SB, Wynwood SJ, et al. Human leptospirosis infection in Fiji: an eco-epidemiological approach to identifying risk factors and environmental drivers for transmission. PLoS Negl Trop Dis. 2016;10(1):e0004405.

Leptospirosis is a highly prevalent yet under-recognised disease. This zoonotic disease is particularly problematic in developing nations as its incidence increases across the globe (1). The Leptospira bacteria colonise the kidneys of the carrying animals, such as rodents and livestock. Bacteria are then released into the environment through the urine of the host animal (2). Therefore, any contact with either the animal or soil and water contaminated by its urine can result in infection transfer.

One of the reasons the disease is under-recognised is that it can be difficult to diagnose. The symptoms are particularly variable, ranging from very mild to life-threatening (1). Leptospirosis is classically described as a biphasic illness where, after an initial sudden onset of febrile illness, there is a period of mildly symptomatic disease for 10-20 days, before the fever returns. Importantly, the infection causes approximately 60 000 deaths per year around the world, and many more are affected by severe illness (3).

Leptospirosis is particularly problematic in tropical regions, including the Pacific, as the climate is ideal for bacterial survival (4). Outbreaks of the disease are typically linked with climate-related changes, such as flooding or extreme events (4). In Fiji, being of iTaukei ethnicity was found to be a significant risk factor for leptospirosis, as was living in villages or regions without treated water, or close proximity to livestock (5).

Leptospirosis is relatively manageable with antibiotic therapy, although its effectiveness has been brought into question (1). As with many infectious diseases, appropriate hygiene and access to clean water are important factors in mitigating disease transfer, and it is more important to prevent the disease from occurring, particularly in developing nations. Whilst climate-based risks for leptospirosis are unavoidable, such as flooding and natural disaster, raised awareness for the zoonotic disease can assist in reducing transmission in trying times.

Ultimately, leptospirosis is an important infectious disease in Pacific Island Countries and Territories, as it has the potential to lead to significant mortality. Whilst the region is predisposed to Leptospira proliferation due to climate-based factors, addressing modifiable risks for leptospirosis can reduce the impact of the disease.

1.              Bharti AR, Nally JE, Ricaldi JN, Matthias MA, Diaz MM, Lovett MA, et al. Leptospirosis: a zoonotic disease of global importance. The Lancet infectious diseases. 2003;3(12):757-71.

2.              Adler B, de la Peña Moctezuma A. Leptospira and leptospirosis. Vet Microbiol. 2010;140(3-4):287-96.

3.              Costa F, Hagan JE, Calcagno J, Kane M, Torgerson P, Martinez-Silveira MS, et al. Global morbidity and mortality of leptospirosis: a systematic review. PLoS Negl Trop Dis. 2015;9(9):e0003898.

4.              Lau CL, Smythe LD, Craig SB, Weinstein P. Climate change, flooding, urbanisation and leptospirosis: fuelling the fire? Trans R Soc Trop Med Hyg. 2010;104(10):631-8.

5.              Lau CL, Watson CH, Lowry JH, David MC, Craig SB, Wynwood SJ, et al. Human leptospirosis infection in Fiji: an eco-epidemiological approach to identifying risk factors and environmental drivers for transmission. PLoS Negl Trop Dis. 2016;10(1):e0004405.