Human avian influenza virus serotypes in a tertiary hospital in Nigeria

Background: Nigeria suffered waves of Highly Pathogenic Avian Influenza (HPAI) outbreaks that peaked twice in February 2006 and February 2007. The outbreaks affected 3,057 commercial and rural household farms causing 1.3 million of the country's poultry destroyed. The burden of Influenza is likely to be under estimated and because of the unstable nature of the virus it call for the mapping of this virus to specific region, this study therefore seeks to identify the types, prevalence, strain, predilection of the organism so as to monitor the occurrence of influenza in this part of the country with the aim of providing a base line level of intervention of influenza virus and find the candidate virus for vaccine selection and production. This study is a cross sectional survey, our target populations were all pediatric and adult patients admitted at the pediatrics and internal medicine department of ATBUTH who has met the criteria for presence of cough, fever (>37 o C), nasal congestion and dyspnoea. Samples were collected and analyzed using the polymerase chain reaction (PCR), for the presence and sub typing of influenza viruses in respiratory specimens. Overall 5% of the samples collected tested positive for human influenza type A and B. During average epidemics, overall attack rates are estimated to be 10-20%, but in certain susceptible populations such as schoolchildren or nursing home residents, attack rates of 40-50% may occur. 60% of the positive results were among the female samples where as 40% from the male samples.