AN EPIDEMIOLOGICAL STUDY OF ACUTE RESPIRATORY VIRAL INFECTIONS IN CHILDREN IN IBADAN-NIGERIA.

Abstract

A survey of the aetiological agents of acute respiratory infection (ARI) was carried out In Ibadan in order to determine the relative importance of these agents in the acute respiratory diseases. Three hundred and fifty nasopharyngeal aspirates and two hundred and eighty sera were collected from children suffering from acute respiratory infections at the University College Hospital (U.C.H) and a community health centre at Idikan, both lbadan between 1985 and 1987 for detection of antigens and antibody to six respiratory viruses namely;- Respiratory Syncytial Virus. Influenza A and B, Parainfluenza types 1 and 3 and Adenoviruses. Antigen detection was carried out by an indirect fluorescent antibody technique. In addition, RSV antigens were detected in specimens by ELISA. Sera were assayed for antibody by complement fixation test. Out of 350 children examined 74 (21%), had at least one viral antigen In their nasopharyngeal aspirate. In all, 7% of nasopharyngeal aspirate tested were positive for RSV, 4%, 4%, 3%, 2% and 1% were positive for influenza A. Parainfluenza 3, Parainfluenza 1, Influenza B and Adenovirus respectively. Of the 350 nasopharyngeal aspirates 230 were examined in ELISA for RSV antigen; 18 (8%) out of these contained RSV antigen. In a comparison of FA and ELISA tests for RSV antigens in 100 nasopharyngeal aspirated, 4% were positive by the two methods. Of the 280 sera from children tested for complement fixing antibody for the 6 respiratory viruses, 157 (56%) were positive. The prevalence of complement fixing antibody to the individual viral antigen tested were as follows:- The highest prevalence of antibody was to RSV (28%) followed by Adenovirus 16%, ParainfluenZa type 1, 4%. Only 1% of sera tested had influenza A and B complement fixing antibody. Statistical analysis showed that there was no significant difference in the prevalence of respiratory viral infections among the hospital based and community based patients (P> 0.05). This study showed that viruses were very important agents of acute respiratory infections in Ibadan with Respiratory Syncytial virus as the most prevalent.