Investigation of an outbreak of acute respiratory disease in Côte D’Ivoire in April 2007

Abstract

Background: This study aim was to investigate an outbreak of human  cases of unexplained influenza-like illness and fatal acute respiratory infection (ARI), with simultaneous poultry illness and high mortality raising concerns of possible influenza A (H5N1), virus in Cote d’Ivoire in February and March 2007.
Materials and Methods: To investigate the outbreak, we conducted active surveillance in the community and reviewed health registries. Persons meeting the case definition were asked to provide nasopharyngeal  specimens. On the basis of clinical and epidemiological information, specimens were tested using conventional RT-PCR for the M gene of the influenza viruses and hemagglutinin H5 of avian influenza A (H5N1), virus;
negative samples were tested for other respiratory viruses. Specimens from healthy animals were also collected.
Results: Between October 2006, and February 2007, 104 suspected cases of Acute Respiratory Disease that included; 31 deaths recorded. We
collected and tested 73 nasopharyngeal specimens; of which, 2, were positive for human Coronavirus OC43 and 1 for influenza C virus. No
pathogens were identified in animal specimens.
Conclusions: The investigation quickly ruled out influenza A (H5N1), virus as the cause and found laboratory-confirmed cases of influenza C virus and human Coronavirus OC 43 for the first time in both Côte d’Ivoire and in a Sub-Saharan African country. However we were not able to show that these viruses caused the outbreak. Monitoring of influenza viruses must be a priority but other respiratory viruses and non-viral causes may be of interest too.

Key words: influenza virus, human Coronavirus OC 43, epidemic,  respiratory viruses.