Serological evidence for influenza virus activity in Nigeria (1985-1987).
A study to determine the activity of influenza virus among the children population was undertaken between 1985 and 1987 in Nigeria. Paired sera were obtained from children presenting with respiratory diseases at the children emergency and outpatient clinics of the University College Hospital, Ibadan. Forty-two paired sera were examined by haemagglutination-inhibition test to determine HI antibody level of the patients to different serotypes of influenza virus. Ninety percent of the children showed serological evidence of previous contact with influenza A virus subtypes while only 24% were positive when tested against influenza B virus. Twenty-two of the 42 children tested seroconverted to influenza A virus strains while only 2 seroconverted to influenza B virus strain used. Out of the 22 children that seroconverted to influenza A virus, 14 were due to H3N2 A/Mississippi 1/85, 4 to H3N2 A/Leningrad 360/86 and 2 each seroconverted to H1N1 A/Chile 1/83 and H1N1 A/Taiwan 1/180. Two other individuals showed serological conversion to either H3N2 A/Mississippi 1/85 and H1N1 A/Chile 1/83 or H3N2 A/Mississippi 1/85 and H1N1 A/Taiwan 1/86. While cases were seen throughout the year during the period under review, more cases occurred during early (April-May) to peak raining season (September) and during harmattan period (November) in Ibadan area where the study was conducted. It is evident from this study that continuous and synchronous circulation of influenza viruses occur in this environment. There is therefore danger of influenza epidemic under depressed immunity and if the virus is introduced into population with low level of immunity in other parts of the country.
Department of Virology, College of Medicine, University of Ibadan, Nigeria.
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Olaleye
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Omilabu
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Olabode
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Fagbami
D000208:Acute Disease; D000914:Antibodies, Viral / Q000032:analysis*; D002648:Child; D006385:Hemagglutination Inhibition Tests / Q000379:methods; D006760:Hospitalization; D006801:Humans; D009980:Influenza A virus / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology; D009549:Nigeria; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000276:immunology; D012621:Seasons
D000914:Antibodies, Viral