Sentinel surveillance system for early outbreak detection in Madagascar.
BACKGROUND
Following the outbreak of chikungunya in the Indian Ocean, the Ministry of Health directed the necessary development of an early outbreak detection system. A disease surveillance team including the Institut Pasteur in Madagascar (IPM) was organized to establish a sentinel syndromic-based surveillance system. The system, which was set up in March 2007, transmits patient data on a daily basis from the various voluntary general practitioners throughout the six provinces of the country to the IPM. We describe the challenges and steps involved in developing a sentinel surveillance system and the well-timed information it provides for improving public health decision-making.


METHODS
Surveillance was based on data collected from sentinel general practitioners (SGP). The SGPs report the sex, age, visit date and time, and symptoms of each new patient weekly, using forms addressed to the management team. However, the system is original in that SGPs also report data at least once a day, from Monday to Friday (number of fever cases, rapid test confirmed malaria, influenza, arboviral syndromes or diarrhoeal disease), by cellular telephone (encrypted message SMS). Information can also be validated by the management team, by mobile phone. This data transmission costs 120 ariary per day, less than US$1 per month.


RESULTS
In 2008, the sentinel surveillance system included 13 health centers, and identified 5 outbreaks. Of the 218,849 visits to SGPs, 12.2% were related to fever syndromes. Of these 26,669 fever cases, 12.3% were related to Dengue-like fever, 11.1% to Influenza-like illness and 9.7% to malaria cases confirmed by a specific rapid diagnostic test.


CONCLUSIONS
The sentinel surveillance system represents the first nationwide real-time-like surveillance system ever established in Madagascar. Our findings should encourage other African countries to develop their own syndromic surveillance systems.Prompt detection of an outbreak of infectious disease may lead to control measures that limit its impact and help prevent future outbreaks.
Randrianasolo
Laurence
L
Unité d'Epidémiologie, Institut Pasteur de Madagascar, Antananarivo, République de Madagascar.
Raoelina
Yolande
Y
Ratsitorahina
Maherisoa
M
Ravolomanana
Lisette
L
Andriamandimby
Soa
S
Heraud
Jean-Michel
JM
Rakotomanana
Fanjasoa
F
Ramanjato
Robinson
R
Randrianarivo-Solofoniaina
Armand Eugène
AE
Richard
Vincent
V
D000293:Adolescent; D000328:Adult; D018354:Alphavirus Infections / Q000175:diagnosis / Q000453:epidemiology*; D002646:Chikungunya virus; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000517:prevention & control*; D005334:Fever / Q000209:etiology; D006801:Humans; D007223:Infant; D008270:Madagascar / Q000453:epidemiology; D012308:Risk Management; D018571:Sentinel Surveillance; D017678:Sex Distribution