Select Committee on Science and Technology Written Evidence


Annex 4

Additional information from the Natural Environment Research Council (NERC)

  1.  NERC is one of the UK's eight Research Councils. It funds and carries out impartial scientific research in the sciences of the environment. NERC trains the next generation of independent environmental scientists. Its priority research areas are: Earth's life-support systems, climate change, and sustainable economies.

  2.  NERC's research centres are: the British Antarctic Survey (BAS), the British Geological Survey (BGS), the Centre for Ecology and Hydrology (CEH) and the Proudman Oceanographic Laboratory (POL).

  3.  NERC's contribution to the present submission comes from CEH.

  4.  In addition to addressing two of the Committee's specific questions in the main body of the present submission, we here present our opinions of further research required in the UK.

What benefits might be expected from studying avian influenza in UK wildlife species?

  5.  The most obvious answer to this question is that there is very little information at the moment and we really cannot accurately predict the risk of avian influenza to humans in the UK. The benefits would be improved understanding of the possible risks, greater knowledge of the factors that determine viral epidemiological success and the possibility of controlling the pandemic at the virological level.

  6.  A few years ago avian influenza viruses re-emerged and they are now causing major epidemics involving high numbers of fatalities amongst wild and domestic avian species in Asia. In the late 1990's these epidemics appeared to be confined to Hong Kong and nearby regions but by 2003 they had spread to Vietnam and China and are the epidemics currently being recorded amongst avian species throughout southern and northern Asia including Russia. There is every reason to believe that this virus dispersal will continue in a westerly direction into Europe as infected birds migrate during the autumn of 2005. Whilst this in itself presents a major threat to avian species, it is of even more concern since humans exposed to infected birds, particularly poultry, have also been fatally infected. One strain of influenza virus in particular, ie H5N1, referred to as ­highly pathogenic avian influenza (HPAI)" virus, is believed to pose the most likely threat of changing its preference for birds to become a human pathogen, ie a virus that could spread efficiently amongst humans. Such a change could occur either by HPAI virus exchanging appropriate genes with human, porcine or equine strains of influenza virus or by mutation of genes within HPAI virus. If such changes do occur it is believed that a novel virus might arise that could cause an influenza pandemic equivalent to the devastating Spanish flu of 1918-19 which is estimated to have killed up to 40 million humans globally.

  7.  For these reasons, and also because there is a significant lack of information on the presence of these viruses in the UK, we believe it is important to investigate the current situation with regard to avian influenza virus in wildlife species, particularly but not exclusively birds, in the UK. If co-ordinated properly, such an investigation would provide us with the information required to make meaningful predictions as to the risk of pandemic influenza in the UK. Moreover, by co-ordinating the derived information with that currently being obtained throughout Europe and Asia, a deeper understanding of the factors that are most important in determining pathogenicity for humans and other mammalian species would be obtained. Hopefully, this would improve our ability to control influenza virus dispersal and pandemicity in the future.

VIRUSES IN BIRDS IN THE UNITED KINGDOM

  8.  Scientists at CEH and others in Europe have demonstrated that several different pathogenic arthropod-borne viruses circulate in the UK and Europe. Many of these viruses have been introduced by migrant birds from Africa, eastern Europe and Asia. They have been shown to cause a wide variety of clinical manifestations from fever to encephalitis or arthritis. In contrast, there is little information concerning the presence of type A avian influenza viruses in wildlife species in the UK and we have no idea if such viruses could provide a genetic reservoir for exchange with viruses such as highly pathogenic avian influenza (HPAI) virus to create novel human pathogens. Moreover, the HPAI virus is classified as a hazard group 3 pathogen. Therefore, if it is introduced into the UK, it can only be studied in laboratories with appropriate high-containment facilities.

  9.  This potential technical problem has effectively been circumvented by the development of a genetically engineered strain of influenza virus designated NIBRG-14 which will be used for the studies proposed herein. NIBRG-14 virus was engineered by Dr John Wood at NIBSC (Potters Bar, Herts) with a view to its use as a human influenza vaccine. NIBRG-14 is based on the PR8 strain of influenza A virus modified by substituting the haemagglutinin (H5) and the neuraminidase (N1) from the HPAI strain of influenza. However to ensure that this vaccine strain is safe both as a vaccine and also for laboratory diagnostic studies, the haemagglutinin has been modified (by Dr Wood) so that it lacks the polybasic cleavage site in the haemagglutinin gene. Without this cleavage site influenza viruses are of much lower virulence than the strains that contain the cleavage site. This modification reduces the efficiency of release and spread of the virus from cell to cell and host to host.

RECOMMENDATIONS FOR FUTURE STUDY

  10.  Specific information is required relating to the presence of avian influenza virus in UK wildlife species - particularly birds, but not excluding other species such as bats and possibly pigs.

  11.  We suggest to:

    -   look for specific antibodies to the highly pathogenic avian influenza (HPAI) virus using plaque reduction neutralisation tests on the sera of avian and other wildlife species;

    -   look for the presence of specific viral RNA (from HPAI) in the sera and/or tissues of healthy birds and, if positive samples are obtained, identify the viruses by sequencing;

    -   look for the presence of antibodies and/or specific viral RNA to related strains of influenza virus and, if positive results are obtained, identify the viruses by sequencing;

    -   attempt to isolate strains of influenza virus from healthy birds, sequence them and determine whether they contain the basic cleavage site in the haemagglutinin protein that determines virus pathogenicity.

  12.  This approach will have to include the collection and analysis of samples taken from a wide range of areas of the UK, and should cover a wide range of avian species. Advantage should be taken of any ongoing studies by other investigators who are currently sampling bird populations and possibly maintaining stocks of frozen avian blood sera, as these will provide both current and historical perspectives.




 
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