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Annex F Health AND Safety Implications of an Outbreak of Avian Influenza or Newcastle Disease

Guiding principles

1. There are few or no human health or safety implications of Newcastle Disease. This Annex will concentrate on the health and safety aspects of staff dealing with an outbreak of Avian Influenza and with the wider public health aspects which could arise from it.

2. The State Veterinary Service is responsible for the management and eradication of disease in the event of an outbreak of AI, whether low pathogenic or high pathogenic in nature. However, many of the operations carried out in an outbreak will involve other staff, who may be employees of poultry companies or contractors. Exposure to infected birds may be particularly intense during catching, culling and disposal operations and it is important that these are managed with a view to protecting the health of staff. There are two main concerns to be addressed:

(a) protection of the health of individual workers by reducing exposure to material contaminated by the virus and ensuring access to appropriate preventive medication

(b) protection of public health by reducing the likelihood of genetic re-assortment of the virus which could occur if a worker is simultaneously exposed to both human influenza and HPAI. This would involve protecting the individual both from infection with Avian Influenza and immunising them against human influenza.

3. Overall responsibility for protecting public health in the event of an Avian Influenza outbreak in Scotland rests with the NHS Boards. Because of the potential risk to public health (due to concurrent infection with human influenza and the risk of genetic re-assortment and the creation of a pandemic strain of the virus), the local NHS Board will define a local outbreak of Avian Influenza among poultry as an incident presenting actual or potential harm to the public health and establish an Incident Control Team ( ICT) chaired by the Consultant in Public Health Medicine (communicable disease and environmental health) ( CPHM( CDEH)). This team will coordinate aspects to protect human and public health, linking with the Divisional Veterinary Manager and Local Authority. Practical aspects of preventive actions such as ensuring arrangements are in place for the administration of antiviral drugs and influenza vaccine will be coordinated by the CPHM ( CDEH) via the ICT. Health Protection Scotland ( HPS) has produced and circulated guidelines for NHS Boards on the actions to be taken in the event of such an incident, and is reviewing these guidelines in light of the experiences in Orkney, Cellardyke and Norfolk in Spring 2006. Detailed arrangements, however, are likely to vary from area to area based on local circumstances.

SVS Staff and Contractors

4. The SVS retains its responsibilities as employer under Health and Safety legislation to protect employees and contractors against infection with Avian Influenza virus, and it is expected that this will involve use of Personal Protective Equipment ( PPE) of a design and specification suitable for the tasks undertaken, as well as other personal protective measures such as antiviral therapy. The responsibilities of the SVS (and its Occupational Health Provider) will link with the actions identified as necessary by the NHS Board ICT, based on HPS guidelines, to ensure that there is coordination across the whole system.

5. The remainder of this Annex details the advice to SVS veterinary and technical staff on the risks to human health from Avian Influenza ( AI) in poultry, the guidance on wearing personal protective equipment ( PPE) and to outline the recent developments in the provision of antiviral drugs and human flu vaccine to staff engaged in on-farm disease control activities. The guidance is equally applicable to low pathogenic ( LPAI) and highly pathogenic ( HPAI) strains of AI.

Risk of transmission

6. Transmission of Avian Influenza viruses to people remains relatively rare and is associated with direct contact with infected poultry or other birds or their faeces. Faecal material can contaminate dust, soil, water, feed, equipment and clothing and feathers. Transmission to people only occurs with certain strains of Avian Influenza. Symptoms of avian flu in people range from mild conjunctivitis to typical flu-like illness, which can lead to acute respiratory illness, viral pneumonia and can be fatal. Infection with Avian Influenza virus A/H5N1 has been characterised by sudden onset with cough and high fever. There is currently no vaccine for the prevention of avian flu in people, though one is being developed. There is however good evidence that avian flu viruses respond to antiviral drugs, and in the UK oseltamivir (Tamiflu®), or other appropriate antiviral agent would be used for the treatment and prevention of avian flu in people.

7. Avian Influenza has two significant implications for human health:

• the severity of illness that may follow infection with avian flu virus; and

• the potential for adaptation of the Avian Influenza virus A into a strain, that both causes severe disease in humans and spreads easily from person to person, or its transformation, through exchange of genes with a human flu virus, into a novel virus capable of spreading easily between people and causing severe illness on a pandemic scale.

8. Public health control measures in any outbreak of Avian Influenza in poultry in this country will therefore aim to protect people against Avian Influenza and also protect against the risk of genetic re-assortment of the virus. Poultry workers who have not received seasonal flu vaccinations would be offered it as a protection against the possibility of re-assortment with human flu virus. Antiviral therapy, as appropriate, to protect against the development of avian flu will be given to those who may be exposed to the infection through close contact with infected birds.

9. Anyone in contact with diseased birds must follow the precautions detailed in the relevant risk assessments ( SVS staff should refer to guidance in VIPER chapter 46 and chapter 4). Because of the possible different strains and varying infectivity of each strain of Avian Influenza virus to people, a precautionary approach should be taken. Anyone with medical conditions that may increase the risk of infection with Avian Influenza, such as respiratory disease or a reduced immuno-competence will be advised to stay away from poultry farms, avoid all contact with infected birds and seek appropriate medical advice.

10. All SVS staff and contractors who have had, or are likely to have contact with infected birds will be provided with information as to how to protect themselves and their families from infection. To protect against infection, a hierarchy of control measures are needed which include:

• safe working practice in accordance with the risk assessment
• the wearing of all appropriate personal protective equipment by poultry workers/handlers/cullers/veterinarians;
• safe disposal of used personal protective clothing and equipment;
• use of the antiviral oseltamivir (Tamiflu®) or other appropriate antiviral agent for the prescribed period by all who are considered to be at risk of infection and for whom antiviral therapy is not contraindicated;
• vaccination with seasonal flu vaccine of all those considered to be at risk of infection and for whom vaccine is not contraindicated;
• monitoring of health status of persons exposed to infected birds; and
• guidance to those at risk of infection on the personal hygiene measures to be taken to protect their health and to prevent the spread of infection.

Safe Working Practices & Personal Protective Equipment

11. SVS staff should refer to the detailed guidance in Appendix A12 of VIPER chapter 46. It contains information and advice to SVS staff that may be involved in dealing with an infectious disease of poultry and details the precautions they should take to avoid zoonotic infection. It deals with the risk from respiratory and non-respiratory zoonotic infections of poultry. The measures described will reduce the risk of infection from both groups of agents. In addition, physical and chemical hazards may also be encountered whilst working on poultry premises. Details of the relevant Risk and COSHH Assessments on the SVS web site: http://intranet/svsweb/wsdd/h-s/risk_assess.asp

12. Each premises will be different so the initial veterinary inquiry should include an assessment of the risk, based on the information above. Depending on the level of risk, some or all of the measures listed below may be required.

a) Limiting exposure by using methods of inspection, sampling, valuation, slaughter and disposal which minimise the exposure to potentially contaminated environments, infected birds and materials.

b) High standards of personal hygiene will help prevent ingestion and inhalation of infective material and reduce the risk of transmission to others. Thorough washing with soap and water is an effective method of decontamination and may usefully be enhanced by the use of anti-viral hand wash / wipes following effective washing. Further information is in Section H of Chapter 46.

c) If exposure to a contaminated environment is necessary, PPE must be worn, even though under health and safety legislation, the use of PPE would normally be considered as a last resort. To reduce the respiratory risks from the agents involved, suitable and appropriate Respiratory Protective Equipment ( RPE) and eye protection must be worn.

In the event of emergency agencies being required to access an area where SVS believe PPE will be required, it is for SVS to provide suitable PPE.

13. Experience from Holland in their outbreak in 2003 is that the failure to use PPE in accordance with best practice or the failure to wear it at all, was the main reason for the incidences of direct infection in front line workers and close contacts. All SVS staff and people employed as contractors who are considered to be at significant risk of exposure must, as a minimum, use PPE / RPE as follows:

Respiratory protection / Eye protection

• Disposable FFP 3 face piece respirator, with exhalation valve in conjunction with close fitting goggles; or
• Other equipment which gives similar levels of protection includes; half-mask reusable respirators fitted with a P3 filter in conjunction with close fitting goggles, full-face reusable respirator fitted with a P3 filter.
• PPE must be in working order and fit correctly. Training will be provided in the fitting, use and maintenance of RPE. Where a good seal cannot be achieved with other respirators e.g. because of facial hair, a full hood powered respirator should be considered.
• If goggles are worn they must be good quality, comply with EN standards and be of the anti-mist type to allow prolonged periods of use.

Hand protection

• As a minimum, the disposable surgical type rubber/vinyl gloves should be worn. Where available, toughened, tear resistant brands are preferred. Because of the possibility of sensitization latex gloves must not be provided or used.
• Lightweight cut resistant, e.g. 'Kevlar' gloves worn under industrial weight rubber gloves, e.g. 'Marigold' is a good combination for handling birds.

Whole body protection

• Lightweight disposable overalls with hoods- e.g. 'Tyvec (style 1431N) Pro Tech or similar should be worn to prevent contamination of personal clothing.

• Wellington boots - those normally issued to SVS staff will do in most circumstances.

• Mob cap or hair net.

14. PPE must be of good quality, properly maintained and issued individually. Where appropriate, a range of sizes should be available. The 'one size fits all' principle is not an option, badly fitting PPE is at best, inconvenient and at worst, ineffective and potentially dangerous. Note: Current advice is that all-in-one suits (often described as SARS suits) are not required as long as the PPE/ RPE described above is fitted and used according to best practice. This policy is however under constant review.

Medical Intervention & Prophylaxis

15. Individuals with existing respiratory infections should not be exposed to the risk of contracting Avian Influenza and will be deployed on low risk activities. Individuals who have asthma should not work in dusty or other situations that may aggravate their condition and should take medical advice if they are unsure about what work they can do. Staff must seek early medical attention if they experience symptoms of infection and report to their line manager any illness they suspect of being work related.

Vaccination

16. As noted earlier those working with poultry will be offered seasonal flu vaccine as a further protection against the possibility of re-assortment with human flu virus. Vaccine will be given as soon as possible, either before or at time of exposure, and at least within 48 hours of initial exposure. There is no evidence to suggest that the administration of human flu vaccine predisposes an individual to infection with Avian Influenza. The vaccine will be delivered and administered to by clinical staff, coordinated by the local NHS Board outbreak control team chaired by the CPHM ( CDEH). Actions will be based on the guidelines produced by Health Protection Scotland ( HPS) taking local health service circumstances into account.

17. Antiviral therapy will be given as soon as possible, either before or at the time of exposure, and is effective as long as it is administered within 48 hours of initial exposure. The choice of antiviral therapy will be based on the medical advice at the time of the outbreak. The agreement is that stocks will be drawn from the Scottish Executive Health Department ( SEHD) emergency stocks. Current advice is that oseltamivir (Tamiflu®) is the likely product of choice. Arrangements for administration of antivirals may again vary from location to location but the NHS Board outbreak team and the CPHM ( CDEH) will maintain an overview of the arrangements in place.

18. These products are prescription only medicines and can only be prescribed by suitably qualified medical practitioners. Oseltamivir should be prescribed with caution in persons with renal impairment, or who are pregnant or breast feeding. In such cases, or in cases of doubt, staff are advised to consult their General Practitioner and to inform their line manger (in-confidence) of any potential issues or concerns that may prevent them from taking these products. Staff unable to take antiviral therapy will not be expected to undertake on-farm disease control duties on infected, potentially Infected Premises or other high-risk premises. It may be necessary for veterinary and technical staff to stop on-farm duties for a period of time between courses of antiviral therapy. The length of the course and the lay-off period will depend on the product used and medical advice at the time. Staff will be assigned to office duties or non-poultry work during any such lay-off period.

19. Persons not employed by the SVS or SEERAD will be advised to seek health and safety guidance from their employer's Health and Safety adviser or medical practitioner. The local outbreak control team will take an overview of the arrangements in place for such persons and for close family contacts considered to be at risk to ensure that both their personal health is protected and any risk to the public health is avoided. Advice is also available from the Health and Safety Scottish Executive on their website: http://www.hse.gov.uk/biosafety/diseases/influenza.htm

Official Signage for Closure of Footpaths and Outdoor Access

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