The Influenza Viruses Group researches influenza in poultry with a view to achieving better control measures (e.g. vaccination) and understanding the potential of these viruses to cause disease in other species, including humans. There are three main questions the group, which is led by Dr Holly Shelton, is interested in answering:
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Which subtypes of influenza pose threats to poultry?
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What factors affect the virulence of avian influenza?
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Are there subtypes of avian influenza that can resist human anti-viral drugs and could they become able to infect humans?
Dr Shelton’s team works closely with other avian influenza researchers at the Institute for Animal Health, with Professor Wendy Barclay at Imperial College London, and in collaboration with international laboratories that specialise in avian influenza.
Potential PhD opportunity in the Influenza Viruses Group: Is PB1-F2 a virulence factor for avian influenza virus in poultry? More information here:
http://www.iah.ac.uk/students/2012Spec/IRIS_2012-1.pdf
About influenza
Influenza viruses infect a wide range of hosts, including humans, but the normal origin of flu viruses is in populations of wild aquatic birds such as ducks and swans. Often the influenza virus does not cause anything more than a mild illness in these birds, making them an important reservoir from which virus can infect other species such as commercial poultry.
There are many types of influenza, described by a two letter and two number combination e.g. H5N1. The H and the N correspond to characteristic structures on the virus and in the wild there are 16 H’s and 9 N’s, which can potentially exist in all possible combinations i.e. 144 possible strains. Each strain is also designated as highly pathogenic or low pathogenic depending on how they affect their host. Highly pathogenic avian influenza (HPAI) H5N1 hit the news in 1997 when 6 people died from the infection they caught from birds. Sporadic human cases of H5N1 continue with the virus causing up to 60% mortality in those it infects. HPAI of the subtypes H5 and H7 have been observed in nature and cause up to 100% mortality in infected chickens.
In some parts of the world low pathogenic avian influenza is endemic in the poultry populations, for example the H9N2 virus is highly prevalent in the Middle East and H5 viruses are widely spread in South East Asia. Vaccination strategies are in place as both prophylactic and post diagnosis protection for birds in some affected areas which can be a severe financial drain on poultry farmers.
Airway epithelium infected with influenza viruses. (Left) Human influenza virus of the subtype H3N2. (Right) Avian influenza virus of the subtype H5N1. The virus infection is shown in red and the cilia on the airway epthelium is indicated in green.
Selected references
van Doremalen, N., H. Shelton, et al. (2011). "A single amino acid in the HA of pH1N1 2009 influenza virus affects cell tropism in human airway epithelium, but not transmission in ferrets." PLoS One 6(10): e25755.
Roberts, K. L., H. Shelton, et al. (2011). "Lack of transmission of a human influenza virus with avian receptor specificity between ferrets is not due to decreased virus shedding but rather a lower infectivity in vivo." J Gen Virol 92(Pt 8): 1822-1831.
Shelton, H., G. Ayora-Talavera, et al. (2011). "Receptor binding profiles of avian influenza virus hemagglutinin subtypes on human cells as a predictor of pandemic potential." J Virol 85(4): 1875-1880.
Loureiro, S., J. Ren, et al. (2011). "Adjuvant-free immunization with hemagglutinin-Fc fusion proteins as an approach to influenza vaccines." J Virol 85(6): 3010-3014.
Ayora-Talavera, G., H. Shelton, et al. (2009). "Mutations in H5N1 influenza virus hemagglutinin that confer binding to human tracheal airway epithelium."
PLoS One 4(11): e7836.