A description of malaria sentinel surveillance: a case study in Oromia Regional State, Ethiopia

Abstract

Background: In the context of the massive scale up of malaria interventions, there is increasing recognition that the current capacity of routine malaria surveillance conducted in most African countries through integrated health management information systems is inadequate. The timeliness of reporting to higher levels of the health system through health management information systems is often too slow for rapid action on focal infectious diseases such as malaria. The purpose of this paper is to: 1) describe the implementation of a malaria sentinel surveillance system in Ethiopia to help fill this gap; 2) describe data use for epidemic detection and response as well as programmatic decision making; and 3) discuss lessons learned in the context of creating and running this system.

Case description: As part of a comprehensive strategy to monitor malaria trends in Oromia Regional State, Ethiopia, a system of ten malaria sentinel sites was established to collect data on key malaria morbidity and mortality indicators. To ensure the sentinel surveillance system provides timely, actionable data, the sentinel facilities send aggregate data weekly through short message service (SMS) to a central database server. Bland-Altman plots and Poisson regression models were used to investigate concordance of malaria indicator reports and malaria trends over time, respectively.

Discussion: This paper describes three implementation challenges that impacted system performance in terms of: 1) ensuring a timely and accurate data reporting process; 2) capturing complete and accurate patient-level data; and 3) expanding the usefulness and generalizability of the system's data to monitor progress towards the national malaria control goals of reducing malaria deaths and eventual elimination of transmission.

Conclusions: The use of SMS for reporting surveillance data was identified as a promising practice for accurately tracking malaria trends in Oromia. The rapid spread of this technology across Africa offers promising opportunities to collect and disseminate surveillance data in a timely way. High quality malaria surveillance in Ethiopia remains a resource intensive activity and extending the generalizability of sentinel surveillance findings to other contexts remains a major limitation of these strategies.

Figure 1

Map of sentinel facilities.

Figure 2

Screen shot of mobile phone displaying data reporting format used in Ethiopia at the health post level.

Figure 3

Bland-Altman plot of total outpatients seen at each facility (health centres and health posts) per week from the SMS system and the paper system during 2011. The difference between the two measures is shown on the y-axis and the average of the two measures is shown on the x-axis.

Figure 4

Plot of differences between paper and SMS reports of confirmed Plasmodium falciparum cases per week over time at all facilities (health centres and health posts).

Figure 5

Results of Laboratory External Quality Assurance for malaria microscopy: proportion of blood slides read correctly for presence of malaria parasites at health centres (black lines are linear trend lines).

Figure 6

Trends in confirmed malaria cases at all sentinel health centres from January 2010 to August, 2013.

Figure 7

Trends in confirmed malaria cases at all sentinel health posts (grouped by their reporting health centre).

Figure 8

Proportion of patients and confirmed malaria cases seen at health centres (as compared to Health Posts) after full scale up of surveillance at Health Post level. (blue line reflects all OPD patients and red line reflects all confirmed cases).