Understanding the cholera epidemic, Haiti

Abstract

After onset of a cholera epidemic in Haiti in mid-October 2010, a team of researchers from France and Haiti implemented field investigations and built a database of daily cases to facilitate identification of communes most affected. Several models were used to identify spatiotemporal clusters, assess relative risk associated with the epidemic's spread, and investigate causes of its rapid expansion in Artibonite Department. Spatiotemporal analyses highlighted 5 significant clusters (p<0.001): 1 near Mirebalais (October 16-19) next to a United Nations camp with deficient sanitation, 1 along the Artibonite River (October 20-28), and 3 caused by the centrifugal epidemic spread during November. The regression model indicated that cholera more severely affected communes in the coastal plain (risk ratio 4.91) along the Artibonite River downstream of Mirebalais (risk ratio 4.60). Our findings strongly suggest that contamination of the Artibonite and 1 of its tributaries downstream from a military camp triggered the epidemic.

Figure 1

Location of health centers reporting cholera cases in communes along the Artibonite River on October 20, 2010, Haiti. MINUSTAH, United Nations Stabilization Mission in Haiti.

Figure 2

Cholera cases by date of onset of the epidemics and major related events, Haiti. A) Cases in Mirebalais, commune hosting the first cases of cholera; B) cases in seven communes simultaneously struck on October 20 (St-Marc, Dessalines, Desdunes, Grande Saline, Lestere, Petite-Rivière-de-l’Artibonite, Verrettes); C) cases in other communes. Timeline at bottom indicates 1) cholera outbreak in Kathmandu, Nepal; 2) first arrival of newly incoming Nepalese soldiers in Meille; 3) first cases in Meille; 4) first death registered in Mirebalais hospital (patient from Meille); 5) initiation of epidemic investigations and spread into the Artibonite delta; 6) epidemiologic confirmation of cholera cases in Meille; 7) United Nations camp sanitary dysfunction no longer observed.

Figure 3

Spatiotemporal clusters of cholera cases, Haiti (results of SaTScan [Kulldorf, Cambridge, UK] analysis). The first cluster covered 1 commune, Mirebalais, October 16–19; the second cluster covered a few communes in or near the Artibonite delta during October 20–28; the next 3 clusters appeared in the North-West Department (A) during November 11–29, in the West Department (B) during November 14–30, and in the North and North-East Departments (C) during November 21–30. Other departments were affected later.