Epidemiological Update - Cholera - 6 August 2018

Summary of the situation

In 2017, a total of 13,803 suspected cases of cholera were reported on the island of Hispaniola: 13,681 cases (including 159 deaths) in Haiti and 122 cases (including 4 deaths) in the Dominican Republic.

Although the number of cases reported in both Haiti and the Dominican Republic decreased in 2017 compared to 2016, there was a greater decline in the Dominican Republic given that the rate per 100,000 population decreased from 11.5 to 1.20. The rate in Haiti decreased from 374 to 112 cases per 100,000 population between 2016 and 2017.

Similarly, comparing 2016 and 2017, the number of deaths related to cholera decreased by 64% in Haiti (from 446 to 159 deaths) and by 85% in the Dominican Republic (from 27 to 4 deaths).

Up to epidemiological week (EW) 29 of 2018, 2,883 cholera cases were reported on Hispaniola; 99% occurred in Haiti (2,843 cases, including 34 deaths). In addition, Mexico reported a cholera case (Vibrio cholerae O1 toxigenic) in a 43-year-old female patient who acquired the infection in Sinaloa. Symptom onset was on 16 June. Additional laboratory analysis is underway to characterize the strain, and no additional cases have been reported.

The following is a summary of the situation on Hispaniola.

In Haiti between EW 1 and EW 29 of 2018, 2,843 suspected cases were reported, including 34 deaths. The incidence rate for 2018 (until EW 29) is 24 cases per 100,000 population, which is the lowest recorded incidence since the beginning of the outbreak. In the last 8 weeks (EW 22 to EW 29), an average of 103 suspected cases were reported following a peak with 184 cases reported in EW 19. This year, great effort has been made to ensure laboratory characterization of the cases. In 2018, samples for laboratory confirmation were available for 69% of cases; the rate of confirmation varied between 10% and 80% per epidemiological week and department (22% on average).

The cumulative case-fatality rate (CFR) has remained around 1% since 2011.

Most of the cases have occurred in the departments of Artibonite (854 cases), Centre (774), and Ouest (561, which includes the capital city of Port-au-Prince). A similar situation was observed in 2017 in which most of the cases were reported in these same departments, indicating that the focus of circulation persists in these areas.

In the Dominican Republic between EW 1 and EW 29 of 2018, 41 suspected cases of cholera were reported, representing a decrease of 57% compared to the total reported during the same epidemiological period in 2017 (96 cases). No deaths have been reported in 2018. Between EW 28 and EW 29, 20 suspected cases of cholera were reported, of which 19 were reported in the municipality of La Descubierta, Independencia Province (bordering Ouest Department in Haiti). Samples were collected for 5 of the cases: 3 were negative for V. cholerae and results are pending for the remaining 2 cases.