Surveillance of Leprosy in Kiribati, 1935-2017

Abstract

In Kiribati, unlike most countries, high and increasing numbers of cases of leprosy have been reported despite the availability of multidrug therapy and efforts to improve case finding and management. Historic records show that 28 cases had been identified by 1925. A systematic population survey in 1997 identified 135 new cases; the mean incidence rate for 1993-1997 was 7.4/10,000 population. After administering mass chemoprophylaxis, the country reached the elimination threshold (prevalence <1/10,000), but case numbers have rebounded. The mean annualized rate of new cases in 2013-2017 was 15/10,000 population, with the highest new case rates (>20/10,000 population) in the main population centers of South Tarawa and Betio. Spread is expected to continue in areas where crowding and poor socioeconomic conditions persist and may accelerate as sea levels rise from climate change. New initiatives to improve social conditions are needed, and efforts such as postexposure chemoprophylaxis should be implemented to prevent spread.

Keywords: Kiribati; Makogai; Mycobacterium leprae; bacteria; crowding; leprosy; tuberculosis and other mycobacteria.

Figure 1

Age-standardized incidence rates (cases/10,000 population) of leprosy recorded, by year and type, from the case register of the National Leprosy Unit, Nawerewere Hospital, Kiribati, 1988–2018. Bars at top indicate timing of passive case finding (A and C), a national screening program (B), active case finding (D), an intensified awareness program (E), and case finding in household contacts (F).

Figure 2

Distribution of cases of leprosy, by age group and type, Kiribati, 1988–2018. Points represent the pooled mean proportion of cases by age. Vertical lines represent bootstrapped 95% CIs.

Figure 3

Age-specific incidence rates (cases/10,000 population) for multibacillary and paucibacillary leprosy, by age group, Kiribati, 1988–2018. A) Age 0–14 years; B) 15–24 years; C) 25–64 years. Points represent the age-specific rate and vertical lines 95% CIs. Solid lines indicate the locally estimated scatterplot smoothing moving average of age-specific incidence rates of paucibacillary leprosy; dashed lines, of multibacillary leprosy.