Human leptospirosis in the central division of Fiji: a retrospective epidemiological study

Abstract

Background: Leptospirosis is a major cause of human disease in Fiji. However, the epidemiology is poorly defined. This study was conducted to determine the epidemiology of human leptospirosis in the Central Division and to characterize the largest urban outbreak in Fiji.

Methods: A retrospective study was conducted using routine leptospirosis surveillance data collected from 1 January 2012 through 30 June 2020. Descriptive analysis was performed to evaluate changes in demographic characteristics and incidence over time.

Results: A total of 2248 cases were reported over the 8.5-y study period. Average annual incidence was 73.9 cases per 100 000 population, with the annual incidence ranging from 45.6 cases per 100 000 population in 2012 to 177.2 cases per 100 000 population in 2019. Overall, most cases were indigenous Fijians (82.6%) and males (53.3%). The proportion of females increased steadily from 37.8% in 2012 to 50.3% in 2020. On 28 January 2019, an outbreak of leptospirosis was declared in the Central Division. During this outbreak, the proportion of female cases (50.5%) was higher and cases among Fijians of Indian descent also increased (18.3%).

Conclusions: Study findings demonstrate changes in the epidemiology of leptospirosis in the Central Division. Increasing incidence in urban settings and among population groups previously considered low risk (female and Fijians of Indian descent) indicates shifts in risk factors and transmission patterns that warrant review of existing measures and strategies for nationwide disease control.

Keywords: Fiji; climate change; emerging diseases; epidemiology; leptospirosis; outbreak.