Secondary data analysis of national influenza reference laboratory, Abuja, Nigeria, May, 2015

Abstract

Purpose: Iinfluenza viruses A/B are responsible for epidemic of respiratory illnesses associated with increased rate of hospitalization while the highly pathogenic avian influenza causes huge economic loss/death. Objectives of the analysis are: To describe the seasonality of influenza, determine the circulating virus strains, determine the trend of the virus in Nigeria and provide recommendations. Methods & Materials: The primary sources of data are the four sentinel sites (Abuja, Kano, Nnewi and Lagos). Influenza surveillance data collected from April 2008 to July 2014 was cleaned and analyzed using Epi-Info version 3.5.1. Analysis of result by age-group, sex, site, trend, and influenza types, subtypes and type of case was conducted. Results: A total record of 11199 collected from April 2008-July 2014 documented. Influenza virus type A (FluA) was 662 (5.9%), (FluB) was 392 (3.5%) and negatives were 10185 (90.9%). The subtype of Influenza Apdm(09), AH1N1 was 261(2.30%), A/H1 is 15(0.10%), A/H3 277(2.50%), subtyped were 48(0.40%), unsubtypeable were 413 (3.70%). Female had 460 (0, 46%) both FluA/B, male had 539 (0.54%) FluA/B. Type of case were ILI 9011 (80%), SARI 2096 (18%), Novel H1N1 27 (0.2%%), and AI 4 (0.04%). Age-group with the highest number of positive was 1-10 with 853. State with the highest positive was Abuja 3325(29.8%) followed by Kano 3507(31.4%), Lagos 2729 (2729%) and Nnewi 1604(14.4%). The highest peak of Influenza activity with a subtype A/H3 was in 2012, while pdm (09) AH1N1 was the highest in 2010, while A/H1 has diminished with little activity in 2009 and 2010. Conclusion: Thus, surveillance is effective in picking the circulating and trend of virus. The need for collaboration between the animal and human aspect of influenza surveillance to be fully integrated is highly recommended to enable track new strain of influenza virus. Sharing of data gathered between ministry of Agriculture and Health will also help in future planning.