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Ireland - LPNAI H5N2 avian influenza at pheasant farm in Cork in March 2012 - Epi-Insight report

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  • Ireland - LPNAI H5N2 avian influenza at pheasant farm in Cork in March 2012 - Epi-Insight report

    Epi-Insight
    volume 13 issue 5 May 2012

    Avian influenza outbreak in Cork
    Influenza viruses circulating in animals can cause illness in humans. The primary risk factor for human infection appears to be direct or indirect exposure to infected live or dead animals or contaminated environments. We describe an outbreak of avian influenza that occurred in Ireland in March 2012.

    On Friday 30th March, 2012, the HSE Health Protection Surveillance Centre was notified by the Senior Veterinary Inspector from the Department of Agriculture, Food and the Marine, of avian influenza in samples taken from sick and dead pheasants in an open air pen in Clonakilty, Cork, which were part of a group of 153 pheasants being reared for release. There were three dead and five sick, and post mortem examination had shown signs of pneumonia. At time of notification, the laboratory results available were H5 positive via matrix & H5 PCR, and N1 negative via PCR. Results on whether this was highly pathogenic (HP) or low pathogenic (LP) avian influenza (AI) would not be available for another 72 hours.

    In accordance with the Pandemic Influenza Expert Group’s “Guidance on the public health actions to be taken on notification of avian influenza in birds in Ireland”, the following actions were taken in relation to human health1:

    HSE South were notified so that prompt public health actions could be taken
    Protective measures were implemented for contacts, i.e. persons with significant exposure to infected pheasants or their droppings and for all persons involved in carrying out outbreak control activities (sampling, culling, cleaning etc). The so-called “strict approach” to public health management was taken, pending pathogenicity results. The strict approach included keeping the number of humans exposed to a minimum, providing oseltamivir post-exposure prophylaxis where appropriate, and following up those who had been exposed. For those who had not been vaccinated against seasonal flu, vaccination was offered, in an attempt to avoid dual infection with human and avian influenza, with the theoretical possibility of emergence of a novel flu virus.
    The fact that this was an animal health problem and the low risk to the general public was emphasised in press communications.
    Local Public Health Actions

    Following notification by HPSC and liaison with the local Senior Veterinary Inspector (SVI), local public health actions commenced. The SVI provided a list of those initially identified as contacts of the avian source. Further information was obtained from the SVI and gun club members, where the birds were located, on how the birds were housed. They were kept in an outdoor pen, surrounded by wire with netting over the top. Within the pen there were a number of wooden shelters. A decision was taken that all those identified would be contacted and a risk assessment of their level of contact undertaken – all those who had handled the birds or had significant contact with droppings within the last seven days would be offered Oseltamivir prophylaxis. In practice the vast majority of contacts had directly handled the birds.

    Contacts of the Avian Source

    The contacts fell into two main groups, the gun club members and the Department of Agriculture Food and the Marine staff involved in the examination or culling of the affected birds.

    Gun Club members

    An initial list of 15 contacts was provided by the SVI. Of these, ten were identified as requiring prophylaxis and five were assessed as not requiring it. An additional three contacts requiring prophylaxis were identified by other gun club members. In summary, 18 potential gun club contacts were identified, of which 13 were given prophylaxis.

    Department of Agriculture, Food and the Marine Staff

    Staff identified as contacts included those involved in the examination of sick birds, performance of post mortems or euthanasia on dead birds. In all, five Veterinary Officers and three technical agricultural officers/laboratory staff were given prophylaxis.

    In total, 26 potential contacts were assessed and 21 were identified as requiring prophylaxis.

    All those requiring prophylaxis were given an “Avian Influenza pack”, the contents of which are given in the box below. The contacts’ GPs were contacted and informed of the situation.



    Animal health measures

    On the infected premises, all poultry (pheasants) were culled on confirmation of H5. The carcasses were destroyed by rendering. An investigation was undertaken to identify the possible source of infection and all contact premises. The premises was cleaned and disinfected, with final cleaning and disinfection taking place on 2nd April. There was a restriction on re-stocking for 21 days following cleaning and disinfection.

    An initial temporary control zone (TCZ) of 1 km radius around the infected premises was set up, within which poultry and captive birds were confined. Moving hatching eggs, table eggs, poultry meat, poultry carcases, waste, droppings, slurry, used litter, manure of poultry or other captive birds, poultry feed, utensils, materials or anything likely to transmit avian influenza from poultry holdings (except under authorisation) was prohibited. There was disinfection at entrances to poultry holdings and bird houses.

    On Monday 2nd April the avian influenza was identified as low pathogenic notifiable avian influenza (LPNAI), H5N2. In the absence of symptoms in contacts, and the confirmation of LPNAI, the response was scaled down to the “standard approach”. All contacts given prophylaxis were contacted, informed of the results, advised to contact public health if symptoms developed, and to stop Oseltamivir.

    Once LPNAI was confirmed the measures in the restricted zone were amended to the following:

    Census of all premises containing commercial poultry or captive birds
    Examination and sampling of commercial poultry flocks
    Prohibition on movements of poultry, other captive birds, other animals from poultry farms, eggs and poultry litter/manure (except under certain conditions and under licence)
    Ban of bird gatherings
    Ban of the release of game birds
    Biosecurity measures for people and vehicles moving to and from premises containing poultry or captive birds
    These measures remained in place for 21 days, until 23 April.

    Discussion

    The only outbreak of highly pathogenic avian influenza recorded in Ireland was H5N8 in 1983. The virus was confirmed on three turkey farms and one duck farm 2. The last outbreak of LPNAI was H7N7 in 1998. This outbreak involved 29 farms, and affected 27 commercial turkey flocks, one turkey breeder flock and one broiler breeder flock 3 Although this outbreak of low pathogenic H5N2 in pheasants was the first outbreak in poultry since 1998, active surveillance for avian influenza in wild birds in Ireland has detected low pathogenic avian influenza viruses, including H5 subtypes, in hunted waterfowl (personal communication) 4. Avian influenza surveys in wild birds worldwide regularly detect low pathogenic strains. Active surveillance in hunted wild birds ceased in 2011, with sampling focusing on passive surveillance for highly pathogenic H5N1 in birds found dead.

    This outbreak allowed us to test national guidelines and local protocols for dealing with avian influenza. Local Department of Public Health protocols and action cards, based on the national avian influenza guidelines, had been developed for response to an incident of avian influenza. The existence of these local plans, pre-prepared avian influenza packs and a stockpile of Oseltamivir allowed a rapid local response.

    There was good communication and liaison nationally and locally between HPSC, public health and the Department of Agriculture, Food and the Marine, which facilitated early notification and the prompt identification of contacts.

    Some issues were identified in the outbreak. The current national avian influenza guideline states that active surveillance should be carried out on all contacts - “active follow-up will be done by public health by telephone” for seven days after the last exposure. Experience from the 2009 influenza pandemic containment phase was that phoning contacts daily was extremely difficult and time intensive with poor results, as many people were un-contactable. In this incident the decision was made locally to have passive rather than active surveillance. The contacts were given information on symptoms, a digital thermometer, a temperature recording chart and a number to call the Public Health doctor (including out of hours) if they developed any symptoms or had any concerns. We consider that this is a more appropriate surveillance mechanism. The contacts expressed no concerns with the instruction to contact public health, if required.

    The assessment of contacts included the Veterinary Officers who had performed the post mortems on the birds. Using the Irish guidelines they were assessed as needing chemoprophylaxis, although they had used appropriate PPE. In the UK such contacts are only recommended to have prophylaxis if they have not used PPE during their exposure. The Irish guidance should be reviewed on this issue.

    The avian influenza subcommittee of the Pandemic Influenza Expert Group will be reconvened shortly to consider the learning points from this incident and to update and amend the national guidelines.

    Fiona Ryan, Department of Public Health HSE South, Sally Gaynor, Department of Agriculture, Food and the Marine, Pat Raleigh, Central Veterinary Laboratory, Derval Igoe, HPSC.

    Pandemic Influenza Expert Group. Pandemic Preparedness for Ireland. Supplement 11: Guidance on public health actions to be taken on notification of avian influenza (AI) in birds in Ireland, November 2008. Available here, last accessed 23.04.2012

    Murphy, T.M. (1986). The control and epidemiology of an influenza A outbreak in Ireland.

    Acute Virus Infections of Poultry. Edited by McFerran, J.B. and McNulty, M.S. Martinus

    Nijhoff: Dordrecht, pp.23-28.

    Campbell G. and De Geus H. (1998). Non-Pathogenic Avian Influenza in Ireland in 1998. In Proceedings of the Joint Fifth Annual Meetings of the National Newcastle Disease and Avian Influenza Laboratories of Countries of the European Union. Held in Vienna, 9th-10th November 1998

    P. J. Raleigh, O. Flynn, M. O'Connor, T. O'Donovan, B. Purcell, M. De Burca, V. Regazzoli, D. Minihan, J. Connell, B. K. Markey And D. J. Sammin. Avian influenza viruses detected by surveillance of waterfowl in Ireland during 2003–2007. Epidemiology and Infection (2009), 137: pp 464-472
    Last edited by sharon sanders; May 3rd, 2012, 09:51 PM. Reason: added bolding
    Twitter: @RonanKelly13
    The views expressed are mine alone and do not represent the views of my employer or any other person or organization.
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