A review of the surveillance systems of influenza in selected countries in the tropical region

Abstract

Influenza viruses cause annual epidemics of respiratory tract disease that affect all age groups. Many developing countries do not have an influenza surveillance system or adequate laboratory capacity for  virus detection. The objective of this study was to describe the influenza surveillance systems in the  different countries in the tropics and to identify outstanding research needs. A questionnaire was designed and sent to 52 NICs and MoHs in the different countries in tropical Asia and Africa to gather information on the surveillance systems, sentinel sites, specimen and data collection, and laboratory testing. Replies were received from 32 NICs and MoHs (61.5% response) – 17 were located in tropical Asia and 15 in  Africa. There are 20 WHO recognized NICs in tropical Asia and 14 in tropical Africa, all with virus isolation and polymerase chain reaction (PCR) testing capacity. Of the Asian countries, only Hong Kong and Singapore reported that the patient population from the sites represents the broader community. In tropical Africa, only Senegal has sentinel sites distributed all over the country contributing to the  geographic representativeness of the surveillance system. The rest of the countries in Africa have just  established their influenza surveillance system in the past decade  and are working toward geographic expansion of the ILI and SARI sites. Limited laboratory capacity or  infrastructure to perform influenza surveillance makes difficult to justify the importance of influenza vaccine or  other influenza control measures as a strategy for improving population health in the tropical region.

Key words: Tropical region, influenza surveillance, epidemics of respiratory