Sero-Detection of Avian Influenza A/H7 in Nigerian Live-Bird Markets in Plateau State

Avian influenza has been reported in domestic birds in Nigeria since 2006 and subtype H5 of the Gs/Gg lineage has continued to be detected up till date. It has been suggested that waterfowls and local birds sold in live-bird markets may be natural reservoir and source of reinfection of different subtype of avian influenza in poultry farms. This study aims at serodetection of avian influenza virus in waterfowls and local birds at live-bird markets in Plateau State, Nigeria. A total of three hundred and nine (309) blood samples were collected over a period of three months and two hundred and ninety-two (292) sera were analysed by c-ELISA for influenza A nucleoprotein using standard protocols. Haemagglutination Inhibition (HI) specific for subtypes H5, H9, and H7 was also carried out using standard protocols on ELISA positive samples. The results showed seroprevalence of 5.14% (n=15) for influenza A. Serotype H7 was thereafter detected by HI in 5 of the 15 influenza A positive samples. The H7 positive sera also reacted with H7N3, H7N4, H7N1 and H7N7 virus strains with HI titre ranging between 1:32 to 1:512. This investigation for the first time showed serological evidence of influenza A subtype H7 in local birds and waterfowls sold at the live bird market in Nigeria. Further virological surveillance to isolate the virus is important in order to better understand influenza virus epidemiology in Nigeria and the potential risk that other subtypesof influenza poses to poultry production and public health. Keywords: Influenza A, subtype H7, serological detection, live bird market, Nigeria.

The epidemiology of seasonal influenza after the 2009 influenza pandemic in Africa: a systematic review

Background: Influenza infection is a serious public health problem that causes an estimated 3 to 5 million cases and 250,000 deaths worldwide every year. The epidemiology of influenza is well-documented in high- and middle-income countries, however minimal effort had been made to understand the epidemiology, burden and seasonality of influenza in Africa. This study aims to assess the state of knowledge of seasonal influenza epidemiology in Africa and identify potential data gaps for policy formulation following the 2009 pandemic. Method: We reviewed articles from Africa published into four databases namely: MEDLINE (PubMed), Google Scholar, Cochrane Library and Scientific Research Publishing from 2010 to 2019. Results: We screened titles and abstracts of 2070 studies of which 311 were selected for full content evaluation and 199 studies were considered. Selected articles varied substantially on the basis of the topics they addressed covering the field of influenza surveillance (n=80); influenza risk factors and co-morbidities (n=15); influenza burden (n=37); influenza vaccina- tion (n=40); influenza and other respiratory pathogens (n=22) and influenza diagnosis (n=5). Conclusion: Significant progress has been made since the last pandemic in understanding the influenza epidemiology in Africa. However, efforts still remain for most countries to have sufficient data to allow countries to prioritize strategies for influenza prevention and control. Keywords: Influenza; epidemiology; review; Africa; post pandemic.

Amino acid replacements of the polymorphic locuses of the hemaglutinin, neuraminidasa and nucleoprotein genes of the influenza virus A strains H1N1 and H7N9

Aim. Significant variability contributing to the formation of highly virulent variants, widespread distribution in natural reservoirs, the ability to overcome interspecific barriers and the ease of the airborne pathway contribute to the development of epidemics and pandemics of respiratory infections. Determination of polymorphic sites and type of polymorphism of the investigated virus subtype gene sequences will allow to determine amino acid substitutions and to establish RNA targets for genotyping. Methods. The analysis was performed on the nucleotide sequences of genes HA, NA and NP of strains H1N1 and H7N9 of avian influenza A virus obtained from the NCBI base. Amino acid sequences of genes were obtained by translation of nucleotide gene sequences using MEGA 6. Polymorphic loci and cluster analysis were performed using MEGA 6 using the ClustalW algorithm.Results. The nucleotide sequences of HA, NA and NP genes were investigated, as well as their translation products inavian influenza A strains H1N1 and H7N9. The polymorphic regions and type of polymorphism of the sequences were determined. Conclusions. Polymorphism regions were detected on the nucleotide sequences of the HA, NA, and NP genes (H1N1 and H7N9 strains) and their translation products. The polymorphism of the HA, NA, and NP genes (strain H1N1) is shown to be higher than the polymorphism of HA, NA, and NP (strain H7N9) due to the presence in the first significant number of synonymous triplets. Keywords: influenza A virus, hemagglutinin, neuraminidase, nucleoprotein, polymorphism.

Pandemic (H1N1) 2009 Cases in Nepal

We analyzed the data available in Nepal during this pandemic in order to determine the epidemiological, clinical and virological characteristics of pandemic influenza A in 2009. The test was conducted by real-time Reverse Transcription – Polymerase Chain Reaction on sample from patients with suspected influenza-like illnesses. Out of 538 cases were tested, 32 % were positive for pandemic influenza A 2009 and the infection rate was highest for cases of 11-20 years and lowest in >50 years of age. Keywords: Influenza A ; pandemic; RT-PCR; surveillance.

Effectiveness of the Brazilian influenza vaccination policy, a systematic review

Since 1999, Brazil has undertaken annual influenza vaccine campaigns, free of charge, targeting the elderly population, health professionals, and immune-deficient patients. We conducted a systematic review of literature in order to evaluate the effectiveness of the initiative. We used the keywords influenza, vaccine, Brazil and effectiveness to search the main databases. Thirty-one studies matched our inclusion and exclusion criteria. Influenza vaccine coverage among the elderly is high, though not as high as suggested by the official figures. Estimates on effectiveness are scarce. The majority come from ecological studies that show a modest reduction in mortality and hospital admissions due to influenza-related causes. Such reduction is not evident in the North and Northeastern states of Brazil, a finding that is probably related to the different seasonal pattern of influenza in equatorial and tropical regions. Brazilian epidemiologists still owe society better-designed studies addressing the effectiveness of influenza vaccine campaigns.