The highly pathogenic avian influenza (H5N1 subtype) recurred in Nigeria after 9 months period of no reported case. A critical look at possible sources of the re-occurrence was desirable. The objective of this study was to determine whether avian influenza viruses were present at reasonably detectable levels (0.5%) in possible “bridge” species of wild and domestic birds. The study was conducted in 8 Nigerian states. A total of 403 birds from 40 species were sampled. Virus isolation was done in embryonated chicken eggs according to standard protocols. The test results were all negative for avian influenza viruses. The overall confidence interval (CI) calculated in R using the exact binomial confidence interval function was 0–0.007406. Tawny Eagle (Aquila rapax) was the lowest sampled 0.3% (1/403) and Red-billed Firefinch (Lagonosticta senegala) the highest 11.7% (47/403). The limitations of the sample size and possibly designing effects on the study, as to make concrete conclusions were acknowledged. Species of wild birds, so identified in the study could be useful in future surveys. Furthermore, multidisciplinary and community oriented approach, blending targeted and passive surveillances was suggested. This approach was envisaged to bring about wider coverage of “bridge” species and clearer insight of their possible roles in avian influenza re-occurrences and spread in Nigeria. 1. Introduction Avian influenza (AI) is a highly contagious disease primarily of birds, and caused by influenza A viruses. Influenza A viruses in poultry can be grouped into 2. The exceptionally virulent viruses cause highly pathogenic avian influenza (HPAI), with mortality in affected flock as high as 100%. This group belongs to subtypes H5 and H7, but it is worth noting that not all H5 and H7 viruses’ infection lead to HPAI. All other subtypes cause a milder, primarily respiratory, disease, that is, low pathogenic avian influenza (LPAI) unless exacerbated by secondary infections [1]. Avian influenza is one of the greatest concerns for public health that has emerged from the animal reservoir [2]. The spread of HPAI (H5N1) to countries in which hygienic standards are deficient increases the virus’s pandemic potential and raises concerns about food security particularly in rural villages [2]. Aquatic birds are the sources of avian influenza viruses [3, 4]. Aquatic birds like ducks, geese, swans (Anseriformes), and gulls, terns (Charadriiforms) are thought to be natural reservoirs for avian influenza viruses and are capable of shading the viruses asymptomatically [5, 6]. HPAI
References
[1]
J. D. Brown, D. E. Stallknecht, J. R. Beck, D. L. Suarez, and D. E. Swayne, “Susceptibility of North American ducks and gulls to H5N1 highly pathogenic avian influenza viruses,” Emerging Infectious Diseases, vol. 12, no. 11, pp. 1663–1670, 2006.
[2]
I. Capua and S. Marangon, “Control and prevention of avian influenza in an evolving scenario,” Vaccine, vol. 25, no. 30, pp. 5645–5652, 2007.
[3]
M. J. Pantin-Jackwood and D. E. Swayne, “Pathogenesis and pathobiology of avian influenza virus infection in birds,” Revue Scientifique et Technique, vol. 28, no. 1, pp. 113–136, 2009.
[4]
S. Krauss and R. G. Webster, “Avian influenza virus surveillance and wild birds: past and present,” Avian Diseases, vol. 54, no. 1, pp. 394–398, 2010.
[5]
T. R. Kelly, M. G. Hawkins, C. E. Sandrock, and W. M. Boyce, “A review of highly pathogenic avian influenza in birds, with an emphasis on asian H5N1 and recommendations for prevention and control,” Journal of Avian Medicine and Surgery, vol. 22, no. 1, pp. 1–16, 2008.
[6]
B. Olsen, V. J. Munster, A. Wallensten, J. Waldenstr？m, A. D. M. E. Osterhaus, and R. A. M. Fouchier, “Global patterns of influenza A virus in wild birds,” Science, vol. 312, no. 5772, pp. 384–388, 2006.
[7]
S. Desvaux, N. Marx, S. Ong, et al., “Highly pathogenic avian influenza virus (H5N1) outbreak in captive wild birds and cats, Cambodia,” Emerging Infectious Diseases, vol. 15, no. 3, pp. 475–478, 2009.
[8]
FAO, “Wild birds and avian influenza,” in Wild Birds and Avian Influenza: An Introduction to Applied Field Research and Disease Sampling Techniques, D. Whitworth, S. Newman, T. Mundkur, and P. Harris, Eds., pp. 13–32, FAO, Rome, Italy, 2007.
[9]
A. T. Peterson, S. E. Bush, E. Spackman, D. E. Swayne, and H. S. Ip, “Influenza A virus infections in land birds, People's Republic of China,” Emerging Infectious Diseases, vol. 14, no. 10, pp. 1644–1646, 2008.
[10]
A. C. M. Boon, M. R. Sandbulte, P. Seiler et al., “Role of terrestrial wild birds in ecology of influenza A virus (H5N1),” Emerging Infectious Diseases, vol. 13, no. 11, pp. 1720–1724, 2007.
[11]
A. Fusaro, T. Joannis, I. Monne et al., “Introduction into Nigeria of a distinct genotype of avian influenza virus (H5N1),” Emerging Infectious Diseases, vol. 15, no. 3, pp. 445–447, 2009.
[12]
N. Gaidet, G. Cattoli, S. Hammoumi et al., “Evidence of infection by H5N2 highly pathogenic avian influenza viruses in healthy wild waterfowl,” PLoS Pathogens, vol. 4, no. 8, Article ID e1000127, 2008.
[13]
A. Fusaro, M. I. Nelson, T. Joannis et al., “Evolutionary dynamics of multiple sublineages of H5N1 influenza viruses in Nigeria from 2006 to 2008,” Journal of Virology, vol. 84, no. 7, pp. 3239–3247, 2010.
[14]
W. B. Karesh, R. A. Cook, M. Gilbert, and J. Newcomb, “Implications of wildlife trade on the movement of avian influenza and other infectious diseases,” Journal of Wildlife Diseases, vol. 43, no. 3, pp. S55–S59, 2007.
[15]
T. M. Joannis, C. A. Meseko, A. T. Oladokun et al., “Serologic and virologic surveillance of avian influenza in Nigeria, 2006-7,” Euro Surveillance, vol. 13, article 42, 2008.
[16]
H. Wilking, M. Ziller, C. Staubach, A. Globig, T. C. Harder, and F. J. Conraths, “Chances and limitations of wild bird monitoring for the avian influenza virus H5N1—detection of pathogenshighly mobile in time and space,” PLoS ONE, vol. 4, no. 8, Article ID e6639, 2009.
[17]
U. Hesterberg, K. Harris, D. Stroud et al., “Avian influenza surveillance in wild birds in the European Union in 2006,” Influenza and other Respiratory Viruses, vol. 3, no. 1, pp. 1–14, 2009.
[18]
J. P. Tracey, “Risk-based surveillance of avian influenza in Australias wild birds,” Wildlife Research, vol. 37, no. 2, pp. 134–144, 2010.
[19]
Z. Kou, Y. Li, Z. Yin, et al., “The survey of H5N1 flu virus in wild birds in 14 Provinces of China from 2004 to 2007,” PLoS ONE, vol. 4, no. 9, Article ID e6926, 2009.
[20]
FAO, “Carcass disposal, disinfection,” in Wild Bird Highliy Pathogenic Avian Influenza Surveillance, K. Rose, S. Newman, M. Uhart, and J. Lubroth, Eds., pp. 37–39, FAO, Rome, Italy, 2006.
[21]
N. Gaidet, T. Dodman, A. Caron et al., “Influenza surveillance in wild birds in Eastern Europe, the Middle East, and Africa: preliminary results from an ongoing FAO-led survey,” Journal of Wildlife Diseases, vol. 43, no. 3, supplement, pp. S22–S28, 2007.
[22]
OIE, “Avian influenza: Manual of Diagnostic Tests and Vaccines for Terrestrial Animals,” 2009, http://www.oie.int/eng/normes/mmanual/2008/pdf/2.03.04_AI.pdf.Accessed.
[23]
R. A. M. Fouchier and V. J. Munster, “Epidemiology of low pathogenic avian influenza viruses in wild birds,” OIE Revue Scientifique et Technique, vol. 28, no. 1, pp. 49–58, 2009.
[24]
D. J. Alexander, “An overview of the epidemiology of avian influenza,” Vaccine, vol. 25, no. 30, pp. 5637–5644, 2007.
[25]
I. Capua and D. J. Alexander, “Avian influenza infection in birds: a challenge and opportunity for the poultry veterinarian,” Poultry Science, vol. 88, no. 4, pp. 842–846, 2009.
[26]
V. J. Munster, C. Baas, P. Lexmond, et al., “Spatial, temporal, and species variation in prevalence of influenza A viruses in wild migratory birds,” PLoS Pathogens, vol. 3, no. 5, Article ID 003006, p. e61, 2007.
[27]
P. L. M. Msoffe, D. Bunn, A. P. Muhairwa et al., “Preparation for the prevention and control of highly pathogenic avian influenza in rural Tanzanian village settings,” Avian Diseases, vol. 54, no. 1, pp. 768–771, 2010.
[28]
C. J. Feare, “Role of wild birds in the spread of highly pathogenic avian influenza virus H5N1 and implications for global surveillance,” Avian Diseases, vol. 54, no. 1, pp. 201–212, 2010.
[29]
A. C. Breed, K. Harris, U. Hesterberg et al., “Surveillance for avian influenza in wild birds in the European Union in 2007,” Avian Diseases, vol. 54, no. 1, pp. 399–404, 2010.
[30]
T. J. D. Knight-Jones, R. Hauser, D. Matthes, and K. D. C. St？rk, “Evaluation of effectiveness and efficiency of wild bird surveillance for avian influenza,” Veterinary Research, 2010.
