Implementation of an alert and response system in Haiti during the early stage of the response to the cholera epidemic

Abstract

The start of the cholera epidemic in Haiti quickly highlighted the necessity of the implementation of an Alert and Response (A&R) System to complement the existing national surveillance system. The national system had been able to detect and confirm the outbreak etiology but required external support to monitor the spread of cholera and coordinate response, because much of the information produced was insufficiently timely for real-time monitoring and directing of a rapid, targeted response. The A&R System was designed by the Pan American Health Organization/World Health Organization in collaboration with the Haiti Ministry of Health, and it was based on a network of partners, including any institution, structure, or individual that could identify, verify, and respond to alerts. The defined objectives were to (1) save lives through early detection and treatment of cases and (2) control the spread through early intervention at the community level. The operational structure could be broken down into three principle categories: (1) alert (early warning), (2) verification and assessment of the information, and (3) efficient and timely response in coordination with partners to avoid duplication. Information generated by the A&R System was analyzed and interpreted, and the qualitative information was critical in qualifying the epidemic and defining vulnerable areas, particularly because the national surveillance system reported incomplete data for more than one department. The A&R System detected a number of alerts unrelated to cholera and facilitated rapid access to that information. The sensitivity of the system and its ability to react quickly was shown in May of 2011, when an abnormal increase in alerts coming from several communes in the Sud-Est Department in epidemiological weeks (EWs) 17 and 18 were noted and disseminated network-wide and response activities were implemented. The national cholera surveillance system did not register the increase until EWs 21 and 22, and the information did not become available until EWs 23 and 24, when the peak of cases had already been reached. Although many of the partners reporting alerts during the peak of the cholera epidemic have since left Haiti, the A&R System has continued to function as an Early Warning (EWARN) System, and it continues to be developed with recent activities, such as the distribution of cell phones to enhance alert communication.

Figure 1.

Structure of the A&R System network in Haiti from 2010 to 2011.

Figure 2.

Number of alerts related to public health events by week of receipt (N = 863; from November 8, 2010 to November 6, 2011 in Haiti).

Figure 3.

Distribution of alerts (in percentages) by department based on available data from the A&R System (N = 859); from November of 2010 to November of 2011; Haiti.

Figure 4.

Number of observed cholera cases by department (N = 491,096); from November of 2010 to November of 2011; Haiti.

Figure 5.

Geographical distribution of cholera alerts by department for EWs 17 and 18 of 2011. Data source: PAHO–MSPP Alert and Response System Graph: PAHO/HSD-IR.

Figure 6.

Geographical distribution of cholera alerts by department for EWs 19 and 20 of 2011. Data source: PAHO–MSPP Alert and Response System Graph: PAHO/HSD-IR.

Figure 7.

Geographical distribution of cholera alerts by department for EWs 21 and 22 of 2011. Data source: PAHO–MSPP Alert and Response System Graph: PAHO/HSD-IR.