Hendra Virus and Nipah Virus

Transcription

1 Hendra Virus and Nipah Virus MANAGEMENT AND CONTROL September 2000 Department of Health, Social Services & Public Safety An Roinn Sláinte. Seirbhísí Sóisialta agus Sábháilteacht Phoiblí

2 Contents FOREWORD 2 1. BACKGROUND 3 Recognition of Hendra and Nipah viruses 3 Geographical distribution 4 Clinical features 4 Transmission 5 2. ASSESSING THE RISK 6 Differential diagnosis 6 3. MANAGEMENT OF A PATIENT INFECTED WITH HENDRA OR NIPAH VIRUS 7 Treatment and care 7 Protection of health care professionals 8 Laboratory diagnosis 8 Disinfection 9 Clinical waste 9 Post-mortem examination 9 Disposal of corpses PUBLIC HEALTH ACTIONS 11 Responsibility 11 Surveillance of contacts 11 Planning 12 Incident control team 12 Veterinary action where there is a suspect case of animal Hendra or Nipah virus in the UK 14 Media relations 14 Flowchart 15 APPENDICES 1. Laboratory Containment Level High Security Infectious Disease Units and Laboratories Transportation of patients Isolation procedures and facilities The carriage of dangerous goods Laboratory investigations Clinical waste Health and safety law 33 1

3 Foreword This document has been prepared in light of the recent characterisation by the Advisory Committee on Dangerous Pathogens of two Hazard Group 4 agents - Hendra virus and Nipah virus - that caused zoonotic disease in horses (1994) and pigs (1998) respectively. As these animals are frequently traded or mix with animals from other countries during international events, for example Olympic equestrian events, transmission of these viruses is an increasing possibility, both to other animals and those who care for them. The Department of Health, in conjunction with the Ministry of Agriculture, Fisheries and Food, the Public Health Laboratory Service, the Health and Safety Executive and independent experts, has prepared these guidelines. Both the Advisory Committee on Dangerous Pathogens and the National Zoonoses Group for England have been consulted on the contents. These guidelines are primarily intended to advise health care professionals who may be contacted during exposure incidents. They will wish to take account of the actions described in Chapter 4 in particular. The document is also being made available to others in the medical and allied professions and to anyone else with an interest. It is being published on the Department of Health s website at: Prof Liam Donaldson Chief Medical Officer for England Dr H Campbell Chief Medical Officer for Northern Ireland Sir David Carter Chief Medical Officer for Scotland Dr Ruth Hall Chief Medical Officer for Wales 2

4 1. Background Recognition of Hendra and Nipah Viruses 1. Both Hendra virus (formerly called equine morbillivirus) and Nipah virus are newly recognised zoonotic viruses that have caused disease in animals and, via contact with infectious animals, in humans. The viruses are named after the locations where they were first isolated, in Australia and Malaysia respectively. 2. Both viruses are members of the Paramyxoviridae family, and are classified as Hazard Group 4 agents on the Approved List (approved by the Health and Safety Commission) made under Section 15 of the Health and Safety at Work etc. Act The Control of Substances Hazardous to Health (COSHH) Regulations, impose particular requirements for the handling of biological agents on the Approved List. These viruses have been brought together for the purposes of these guidelines. The definition of a Hazard Group 4 agent is a biological agent that causes severe human disease and is a serious hazard to employees; it is likely to spread to the community and there is usually no effective prophylaxis or treatment available. Distinctions between the viruses, for example in the diseases that they cause, have been made clear wherever possible within this guidance. Hendra virus 3. Human cases of Hendra virus infection have been associated with two outbreaks to date. 2 Hendra virus was first isolated from horses during an outbreak in Brisbane, Queensland, Australia, in September Of the 20 horses that suffered from severe respiratory disease, 13 died. Two people looking after the index horse case developed the disease, and one of them died. In 1995, a third human case (also fatal) was recorded, and thought to be associated with an earlier outbreak in another part of Queensland. The patient had assisted in the post-mortem examinations of two horses in August These three cases are the only known occurrences of Hendra virus infection in humans. 4. The most recently reported animal case of Hendra disease was an isolated confirmed case of a horse in Cairns, North Queensland, in January 1999, which later died. Nipah virus 5. Nipah virus was first isolated in 1999, during an outbreak of viral encephalitis in the Malaysian regions of Perak, Negeri Sembilan and Selangor, between September 1998 and April The total number of suspected human cases was 265, of which 105 were fatal. 3 Those mainly affected were pig farmers, who had had close contact with infected and sick pigs. The outbreak was initially thought to be Japanese encephalitis, but was later confirmed as Nipah virus infection. 1 Control of Substances Hazardous to Health Regulations (1999). In Northern Ireland Control of Substances Hazardous to Health (COSHH) Regulations (Northern Ireland) 2000 apply. General COSHH ACOP (Control of substances hazardous to health) and Carcinogens ACOP (Control of carcinogenic substances) and Biological agents ACOP (Control of biological agents). HSE Books (ISBN ). 2 Mackenzie JS (1999). Emerging viral diseases: An Australian perspective. Emerging Infectious Diseases 5(1): Chua KB, Bellini WJ, Rota PA et al. (2000). Nipah virus: A recently emergent deadly paramyxovirus. Science 288:

5 Hendra Virus and Nipah Virus 6. During March 1999, 11 abattoir workers in Singapore developed a febrile illness (1 fatality) caused by Nipah virus, following close contact with pigs imported from Malaysia. No new cases have been documented in Singapore since restrictions on pig importation were imposed. Geographical Distribution 7. The exact geographical distribution of both Hendra and Nipah viruses has not yet been defined, although, on the basis of known incidents, Australia and South East Asia should be considered as endemic areas. Fruit bats of the genus Pteropus, (also known as the flying fox ), are the suspected natural host of both Hendra and Nipah viruses. 4 They are distributed across an area encompassing North, East and South-East areas of Australia, Indonesia, Malaysia, the Philippines and some of the Pacific Islands. Fruit bats infected with Hendra virus have also been reported in Papua New Guinea. 8. There have been no suspected or confirmed cases of human infection with either Hendra virus or Nipah virus in the United Kingdom to date. In January 1999, five horses imported from Australia were under surveillance having been in contact with a suspected animal case of Hendra virus infection. Laboratory investigations finally excluded Hendra virus infection from the differential diagnosis of the index case. 9. On 26 July 1999 a decision was made by the European Commission (99/507/EC) to restrict the entry of cats and dogs into the EU from Malaysia, and cats from Australia until shown to be negative for Hendra virus and Nipah virus, and officially certified as such. This follows similar import restrictions for both bats and horses. Clinical Features 10. The incubation period for Hendra and Nipah virus infection is generally between 4 and 18 days, although some reports suggest that the incubation period may, in exceptional circumstances, be up to twelve months (as evidenced by the events described in paragraph 3). 11. Of the human cases reported to date, clinical symptoms have ranged in severity from mild to fatal. Onset of disease is usually influenza-like with high fever and myalgia. Sore throat, dizziness, drowsiness and disorientation have also been described. The case fatality rate for clinical cases is about 50%, and subclinical infections may be common. Hendra virus 12. In the first two human cases of Hendra virus infection described, the patients displayed respiratory symptoms, and eventually respiratory failure due to pneumonitis, causing death in one. The other recovered slowly over a 6 week period. In the third, mild meningoencephalitis progressed to severe encephalitis with convulsions, and eventually led to a coma and death. Nipah virus 13. The symptoms of disease associated with Nipah virus in humans have been described as febrile encephalitis and respiratory illness. Later stages of the disease may be accompanied by autonomic instability with fluctuating blood pressure and body temperature. 4 Young PL, Halpin K, Selleck PW et al. (1996) Serological evidence for the presence in Pteropus bats of a paramyxovirus related to equine morbillivirus. Emerging Infectious Diseases 2(3):

6 Background Transmission Reservoir host 14. Fruit bats are thought to be the natural host of both Hendra and Nipah viruses. Infection is widespread and asymptomatic in this animal. Despite frequent contact between fruit bats and humans, studies have shown no serological evidence of infection in bat carers. 5 Hendra virus 15. Laboratory investigations have found that animals other than horses are susceptible to Hendra virus. Horses, cats and guinea pigs all suffer severe disease, and can excrete the virus in their urine. Fruit bats become infected but do not become ill. Nipah virus 16. The first cases of porcine Nipah virus infection occurred on a farm in which fruit trees, frequented by fruit bats, were planted close to pigpens. During the outbreak, antibodies to the virus were detected in other domestic and wild animals dogs, horses, cats and goats. The role of these animals in the spread of infection has not yet been determined. Mode of transmission 17. It is unlikely that either of these viruses are easily transmitted to man, although previous outbreak reports suggest that Nipah virus is transmitted more readily than Hendra virus (see paragraph 5). The risk of transmission from horse to human is thought to be very low. 6 Human-to-human transmission of both Hendra and Nipah viruses has not been reported. The mode of transmission from animal to animal, and from animal to human is uncertain, but appears to require close contact with contaminated tissue or body fluids from infected animals. 18. Experimental studies with both viruses have confirmed the possibility of transmission via close contact with infected body fluids (through cuts and abrasions). Aerosol transmission does not seem to be significant. 7, It should be noted that animals may incubate the virus for up to 18 days and although asymptomatic, are infectious during this period. 20. Those in close contact with animals from endemic areas should wear appropriate personal protective equipment (PPE), such as disposable impermeable gloves, disposable gowns and face visors (which provide both face and eye protection). 5 Selvey L, Taylor R, Arklay A, and Gerrard J (1996). Screening of bat carers for antibodies to equine morbillivirus. Communicable Diseases Intelligence 20: McCormack JG, Allworth AM, Selvey LA et al. (1999). Transmissibility from horses to humans of a novel paramyxovirus, equine morbillivirus (EMV). Journal of Infection 38: Williamson MM, Hooper PT, Selleck PW et al. (1998). Transmission studies of Hendra virus (equine morbillivirus) in fruit bats, horses and cats. Australian Veterinary Journal 76: Middleton D, Westbury H, Morrissy C et al. (1999). Experimental transmission of Nipah virus infection to pigs and cats. In: Programme and abstracts of the XII International Congress of Virology (Sydney, Australia). International Union of Microbiological Societies, 39. 5

7 2. Assessing the Risk 21. The risk of transmission of either Hendra or Nipah virus from sick animals to humans is thought to be low. Because of the paucity of information, there is no means to identify those at low, medium or high risk of infection. However, all those who come into either regular or occasional contact with sick horses (for Hendra virus) or sick pigs (for Nipah virus), should be considered to be at risk of infection, particularly if the animal has been in an area where the virus is known to be endemic, or in an area inhabited by fruit bats. 22. It is thought that humans at greatest risk of infection are those who have been in an endemic area within the previous 28 days and who have had close contact with either a horse suspected of being infected with Hendra virus, or a pig suspected of being infected with Nipah virus. 23. A clinical case definition may include: acute viral, flu-like illness; neurological/respiratory involvement; encephalitis/pneumonitis; an incubation period of 4 to 18 days. As there may be a longer incubation period (e.g. 12 months), suspected cases may not show clinical symptoms. Differential Diagnosis 24. If a patient has been in the North, East or South-East areas of Australia, Indonesia, Malaysia, the Philippines, Papua New Guinea and some of the Pacific Islands during the past month, infection with Hendra or Nipah virus should be included in the differential diagnosis. However, because of the limited knowledge about this disease, it is important that other countries should not necessarily be excluded. 25. Although initial presentation is usually with respiratory disease, it is possible that Hendra virus infection may be confused with Herpes encephalitis or measles encephalitis. 26. Initial confusion of Nipah virus with Japanese encephalitis virus was probably because Japanese encephalitis virus is also associated with pigs, and is endemic in South East Asia including Malaysia. Therefore, laboratory diagnosis may include investigations for Japanese encephalitis virus in addition to Nipah virus. 9,10 9 Goh KJ, Tan CT, Chew NK et al. (2000). Clinical features of Nipah virus encephalitis among pig farmers in Malaysia. New England Journal of Medicine 342 (17): Lim CC, Sitoh YY, Hui F et al. (2000). Nipah viral encephalitis or Japanese encephalitis? MR findings in a new zoonotic disease. American Journal of Neuroradiology, 21(3):

8 3. Management of a Patient Infected by Hendra or Nipah Virus Treatment and Care 27. Treatment is generally a matter of providing intensive supportive care, although there is some evidence that early treatment with an antiviral drug, such as ribavirin, can reduce both the duration of feverish illness and the severity of disease. However, the effectiveness of this treatment is still uncertain. Initial management of patients 28. The risk of transmission of both Hendra virus and Nipah virus from sick animals to humans is thought to be low, and transmission from person to person has not yet been documented. Therefore, the risk of transmission of Hendra and Nipah viruses to health care workers is thought to be extremely low. However, transmission is theoretically possible, as secretions contain the viruses. This is why they have been categorised as Hazard Group 4 agents (see Appendix 1). For the purposes of these guidelines, the risk is managed at Containment Level 4, bearing in mind that appropriate precautions need to be taken in accordance with a local risk assessment. Those assessing the risk may find the Advisory Committee on Dangerous Pathogens (ACDP) Microbiological Risk Assessment: an interim report 11 helpful. 29. Patients suspected of being infected by either Hendra or Nipah virus should be admitted (or transferred if already in hospital) either to an intermediate isolation facility, or to a High Security Infectious Disease Unit (HSIDU) (see Appendix 2), after consultation with the physician in charge. Such discussions are particularly important if it is thought that movement will have a detrimental effect on the patient. Discussions with specialist laboratories at the Central Public Health Laboratory (CPHL) and the Centre for Applied Microbiology and Research (CAMR) (see Appendix 2) may also help with a decision whether to move a patient whilst awaiting confirmation of laboratory diagnosis. Appendix 3 gives guidance on the transportation of patients, and Appendix 4 describes isolation facilities. 30. In the context of caring for a suspected or confirmed case of infection with Hendra or Nipah virus, it is recommended that close contact with body fluids and infected tissues is avoided. Transportation of patients 31. Health authorities are responsible for securing suitable arrangements for the transportation of patients known to be or suspected of being infected with Hendra or Nipah virus. Local policies should include details of such arrangements. There are at present two HSIDUs in England, in London and Newcastleupon-Tyne (see Appendix 2). Patients should be transported at Ambulance Category 3, which signifies that special precautions are required. Qualified ambulance personnel should use appropriate PPE including disposable gloves, face and eye protection, as well as a disposable impermeable gown/apron. More information on the transportation of patients can be found in Appendix Advisory Committee on Dangerous Pathogens (1996). Microbiological Risk Assessment: an interim report. HMSO (ISBN ) 7

9 Hendra Virus and Nipah Virus Protection of Health Care Professionals 32. Hendra virus and Nipah virus are biological agents to which requirements of the Control of Substances Hazardous to Health (COSHH) Regulations 1999 apply. 12 Both are classified as Hazard Group 4 biological agents. 13 The COSHH Regulations require assessments to be made of the risks to health from work activities, and prevention of exposure to risks, or adequate control measures to be put in place if prevention is not possible. All health care workers should be provided with sufficient information, instruction and training about the risks of exposure, and the precautions to be taken if they are likely to be exposed to Hendra or Nipah virus. 33. The number of persons attending a patient should be kept to a minimum. Nursing and medical staff should be informed of the potential risks (see paragraph 32) particularly during periods of intensive care. Suitable PPE, including disposable impermeable gloves, disposable gowns and face visors (which provide both face and eye protection) should be used. Laboratory Diagnosis 34. Diagnosis should be undertaken as quickly as possible. Specimens from suspected Hendra or Nipah virus infected cases should be sent to a High Security Infectious Disease (HSID) reference laboratory, either CPHL or CAMR (see Appendix 2 for contact details). 35. Tests for diagnosis include enzyme-linked immunosorbant assay, immunofluorescence, polymerase chain reaction, virus neutralisation assays and tissue culture. Although none of the above assays is currently available in the UK, the designated specialist laboratories are sufficiently experienced to undertake preliminary virus isolation studies and a PCR system of identification with confirmation by experts in Australia, Malaysia and at The Centres for Disease Control and Prevention (CDC), Atlanta, USA. 36. All work involving the propagation of Hendra virus or Nipah virus must be done in Containment Level 4 facilities. Details on the requirements of Containment Level 4 can be found in Appendix Once the diagnosis has been confirmed, all specimens should be correctly labelled, packed and stored. Their handling should be tracked and audited. 38. The local laboratory should discuss with the HSID reference laboratory whether to send or dispose of any isolates or specimens taken before confirmation of the diagnosis or transportation of the patient to an HSIDU. Any equipment involved should be disinfected or autoclaved as appropriate. Each case should be discussed with staff in the laboratory first, so that specimens are transported correctly (UN 602 compliant packaging). 39. Transport of Hendra virus or Nipah virus, other than in material for diagnostic purposes only, requires prior notification to the Health and Safety Executive (HSE). COSHH Regulations 1999, The Carriage of Dangerous Goods (Classification, Packaging and Labelling) and the Use of Transportable Pressure Receptacles Regulations apply to Hazard Group 4 agents. Specimens cannot be sent by post due to Post Office conditions of carriage. Further details on the carriage of dangerous goods can be found in Appendix Control of Substances Hazardous to Health Regulations (1999). SI 1999/437. Stationery Office. In Northern Ireland Control of Substances Hazardous to Health (COSHH) Regulations (Northern Ireland) 2000 apply. General COSHH ACOP (Control of substances hazardous to health) and Carcinogens ACOP (Control of carcinogenic substances) and Biological agents ACOP (Control of biological agents). HSE Books (ISBN ). 13 Advisory Committee on Dangerous Pathogens (1995). Categorisation of biological agents according to hazard and categories of containment. Fourth edition. HSE Books (ISBN ). 14 In Northern Ireland the Carriage of Dangerous Goods (Classification, Packaging and Labelling) and the Use of Transportable Pressure Receptacles Regulations (Northern Ireland) 1997 apply. 8

10 Management of a Patient Infected by Hendra or Nipah Virus 40. In exceptional circumstances, to preserve the life of a patient, general hospitals without immediate access to a HSID laboratory may be obliged to conduct emergency tests to manage critically ill, high risk patients. In such circumstances, advice should be sought from HSID specialists at an early stage, to agree on what emergency tests may be undertaken (none of which should involve or allow replication of the virus). Risks to hospital and laboratory staff must be minimised. This is strictly an emergency arrangement and is not intended for continuing patient management, as specimen taking and handling are the activities which could most likely lead to mishap and cross-infection. Further details on laboratory investigation can be found in Appendix 6. Disinfection 41. Hendra and Nipah viruses are not known to be particularly resistant to heat or chemicals. Areas and equipment which have not obviously been contaminated with blood, body fluids or laboratory specimens, can be adequately treated by routine washing and cleaning methods. 42. Objects that are soiled by infective or potentially infective secretions or excretions may be disinfected by autoclaving or boiling. Where heat cannot be used, detergents or chemical disinfectants may be used. Normal disinfection procedures can be applied for spillages of potentially infective material. Disinfectants containing 10,000 ppm of available chlorine are recommended for spillages. The use of sodium dichloroisocyanurate (NaDCC) granules is also generally recommended for clinical waste spillages, because made-up solutions lose activity with time and require regular replacement Extreme methods of decontamination, such as the use of powerful chemicals or fumigation, are not recommended. 44. Spilled waste, and any absorbent material used to mop up waste, must be placed in a clinical waste container for disposal as outlined in Appendix 7. Clinical Waste 45. Procedures for the safe disposal of specimens and decontamination of any equipment used, or areas potentially contaminated, must be in accordance with the Schedule 3 of COSHH 16 (see Appendix 7). Post-Mortem Examination 46. Under the hierarchy of controls required by COSHH, exposure to biological agents should be prevented where reasonably practicable. A post-mortem examination on a person suspected or known to have died from Hendra or Nipah virus exposes staff to unwarranted risk and should not be performed. 47. Suspected cases would be those patients who have died from acute respiratory disease or acute encephalitis where an alternative definitive diagnosis has not been made. If the diagnosis is in doubt, a HSIDU (see Appendix 2 for contact details) can be contacted for advice. 48. Needle necroscopy tests should also be discouraged. If thought essential, arrangements can be made for experts to perform tissue sampling. 15 Public Health Laboratory Service (1993). Chemical disinfection in hospitals. HSMO (ISBN ). 16 Control of Substances Hazardous to Health Regulations (1999). In Northern Ireland Control of Substances Hazardous to Health (COSHH) Regulations (Northern Ireland) 2000 apply. General COSHH ACOP (Control of substances hazardous to health) and Carcinogens ACOP (Control of carcinogenic substances) and Biological agents ACOP (Control of biological agents). HSE Books (ISBN ). 9

11 Hendra Virus and Nipah Virus Disposal of Corpses 49. Training and adherence to agreed protocols for safe procedures for body disposal are essential. Standard procedures for burial or cremation apply, although the bodies of patients known or suspected to be infected with Hendra virus or Nipah virus should not be embalmed. Embalming carries significant risk to the operator, as sharp instruments need to be used and a substantial amount of blood is drawn. 10

12 4. Public Health Actions 50. Those thought to be at greatest risk of infection are those who have been in an endemic area within the previous 28 days and who have had close contact with either a horse suspected of being infected with Hendra virus, or a pig suspected of being infected with Nipah virus. See case definition at paragraph 23. Responsibility 51. Consultants in Communicable Disease Control (CCDCs), and Consultants in Public Health Medicine for Communicable Disease and Environmental Health (CPHM (CD & EH)) in Scotland, are responsible for leading the local public health response to known or strongly suspected human cases of Hendra or Nipah virus infection. The State Veterinary Service (SVS) 17 will deal with known or suspected animal cases of Hendra or Nipah virus infection. There will be close liaison between the CCDC/CPHM (CD & EH) and the SVS 17 at all times. Surveillance of Contacts 52. If a horse is suspected of being infected with Hendra virus, or a pig suspected of being infected with Nipah virus, possible human contacts should be traced and informed. The incubation period for Hendra virus infection in a horse is 8 10 days. Horses with transit fever may be mistaken for Hendra virus cases, although transit fever responds to antibiotic therapy within hours. If there is no response to therapy, an animal should be treated as a suspected case of Hendra virus infection. 53. Hendra virus is a notifiable disease under the Specified Animal Pathogens Order Any person who suspects or knows that an animal or carcass is infected with viable Hendra virus must report that fact to a veterinary inspector. Nipah virus is not a notifiable disease. 54. Hendra virus and Nipah virus infections in humans are not notifiable diseases under the Public Health (Infectious Diseases) Regulations Nonetheless, it is advisable that CCDCs assume the responsibility to ensure that all possible human cases are identified, and that surveillance is undertaken. In Scotland, the CPHM (CD & EH) should inform the Scottish Centre for Infection and Environmental Health (SCIEH) and the Scottish Executive of the identification of a probable or confirmed case. The Director of Public Health (DPH) or Divisional Veterinary Manager (DVM) should approach the CCDC / CPHM (CD & EH) who should keep a register of possible contacts. Those individuals should be approached, interviewed, be given reassuring advice and provided with a basic advice sheet. It is important to tell suspected cases that the likelihood of transmission is low, and that person-to-person transmission has not been recorded for either Hendra or Nipah virus. Where possible General Practitioner s (GP) should be informed by the CCDC in writing with a fact-sheet so that they are aware of the symptoms of this infection. 17 In Northern Ireland the Department of Agriculture and Rural Development (DARD) Veterinary Service. 11

13 Hendra Virus and Nipah Virus 55. Contacts of a suspected human case should be advised to visit their GP if they develop relevant symptoms (feverish illness) in the following 3-6 weeks. They should inform their GP that they are under clinical surveillance for either Hendra virus or Nipah virus infection, and take any relevant background information and fact-sheets with them to their GP. 56. Potential cases should be monitored for 2-3 weeks from the last possible date of exposure to infection, and enquires made about the presence of any suspicious symptoms. 57. If a person wishes to go abroad during a period of surveillance, the Public Health Laboratory Service, Communicable Disease Surveillance Centre (CDSC) should be consulted before advice is given. Planning 58. CCDCs and local authorities should work together to prepare joint contingency plans for the control of infectious diseases such as Hendra and Nipah virus, and work out details of local liaison with those concerned. This should include involvement of local veterinary services. 59. Although Hendra and Nipah virus infections are not notifiable diseases (see paragraph 54), all local doctors should be advised to inform their local CCDC immediately, by telephone, if one of their patients is suspected to be suffering from Hendra or Nipah virus infection. Incident Control Team When to form a team 60. The CCDC should convene an Incident Control Team (ICT) when there is a suspected or confirmed case of human infection with Hendra or Nipah virus. The SVS will co-ordinate the veterinary aspects of control centrally, liaising closely with the ICT and providing veterinary representation. In Northern Ireland the DARD Veterinary Service will co-ordinate the veterinary aspects of control. Who to include on the team 61. The ICT should seek support from the Regional Epidemiologist and CDSC in England and Wales, the SCIEH in Scotland and the Regional Epidemiologist, CDSC (NI) in Northern Ireland. The team should include expert representatives from veterinary and human health agencies. Where occupational transmission is suspected, the Health and Safety Executive and the Local Authority Environmental Health Officer should be informed (see Figure 1). When there is a suspected or confirmed case of Hendra or Nipah virus in an animal in Great Britain, the SVS should be represented on the ICT. In Northern Ireland the DARD Veterinary Service should be represented on the ICT. If infection occurred abroad, there should be liaison with the authorities in that country. 12

14 Management of a Patient Infected by Hendra or Nipah Virus Actions for the incident control team 62. The ICT, led by the CCDC, should implement an action plan as follows, adapted in accordance with local needs. Incident Control Team Action Plan (to be adapted to local needs) To provide appropriate care of the patient Ensure that the patient is admitted to a High Security Infectious Disease Unit (HSIDU) or other appropriate isolation facility. Confirm that all categories of staff likely to have contact with the patient, their clinical specimens, or their body fluids, have been advised about appropriate control measures, including protective clothing. To protect contacts of human or animal cases Assess the risk of infection to those who have been exposed to a suspected or confirmed case of human or animal Hendra or Nipah virus infection, arranging clinical surveillance where appropriate. Ensure, in co-operation with the laboratories concerned, that any specimens connected with the patient from tests that may result in propagation of the viruses, and which are not held in a HSID laboratory, are located and retrieved. These may have been sent out before the diagnosis of Hendra virus or Nipah virus was suspected. Consider post-exposure anti-viral treatment (ribavirin) for those at risk of infection with Hendra virus or Nipah virus. However, it should be noted that the efficacy of ribavirin in such situations is yet to be established. When there is a suspected or confirmed human case of Hendra or Nipah virus infection, arrange for the disinfection of articles contaminated by the patient in the domestic setting before they were admitted to hospital. To communicate with others Liaise with appropriate local health and veterinary services. Inform all general medical practitioners, medical directors of all Trusts and the Accident and Emergency Departments in the district, for appropriate cascade according to local plans. Inform the Department of Health (DH) or relevant UK Health Department. Inform the Regional Health Authority under the Untoward Incident or similar arrangements. Liaise with CDSC, who will liaise with the DH in ensuring appropriate communications in the UK and internationally. Co-ordinate a response to media and public enquiries. When there is a suspected or confirmed animal case Co-ordinate a response to media and public enquiries. Ensure that the appropriate Divisional Veterinary Managers and the Ministry of Agriculture, Fisheries and Food (MAFF) are informed of the circumstances of the case as a matter of urgency. In Northern Ireland the appropriate Divisional Veterinary Officer (DVO) and DARD should be informed. 13

15 Hendra Virus and Nipah Virus Veterinary Action when there is a Suspect Case of Animal Hendra or Nipah Virus in the UK 63. The control of an outbreak of Hendra or Nipah virus involving animal cases and human contacts requires the concerted efforts of animal and human health services working in close liaison. The CCDC should ensure that the Divisional Veterinary Manager (MAFF contact) or in Northern Ireland, the Divisional Veterinary Officer (DVO, DARD contact) has been informed. Media Relations 64. Enquiries from the media may be expected at an early stage when there is a suspected or confirmed case of Hendra or Nipah virus infection. It is essential that there should be close co-operation between press offices involved, to ensure accuracy and consistency in the information and advice provided. 65. The ICT should include an experienced press officer. Local outbreak plans should identify (before the event) a named individual to act as press officer, and ensure, as far as possible, that all public statements are made by one person, preferably the CCDC or the press officer, speaking for the health authority, the local authority and the hospital. All enquiries from the media should be referred to this person. 66. Close liaison between the CCDC, press officer, regional health authority and the DH is important. A draft of any local press release should be sent electronically to the DH for consideration before issue. The DH will also liaise with the MAFF, Public Health Laboratory Service and CAMR press officers. CPHMs in Scotland should follow the equivalent procedure. 67. Statements should as far as possible be factual, confirming the number of suspected and/or confirmed cases. It is most important to make strenuous efforts to preserve the anonymity of patients and their families, contacts and neighbourhood. At the same time, everything should be done to allay the fears of the general public, in particular by pointing out the unlikelihood of any spread in the community. 68. Given the importance of such an occurrence, a full report should be written up by the ICT and submitted to the relevant UK Health Department. 14

16 Management of a Patient Infected by Hendra or Nipah Virus Flow Chart 69. Figure 1 outlines the steps to be taken by the CCDC in the event of a suspected or confirmed case of Hendra or Nipah virus infection in an animal or human. Figure 1: Local public health control of a Hendra or Nipah virus incident Clinician, vet or laboratory informs CCDC of strongly suspected or confirmed case of human Hendra/Nipah virus or animal Hendra/Nipah virus with known or suspected human contact Form Incident or Outbreak Control Team Inform LA/PHLS (CDSC, CPHL)/RE/DH/HSE Trace, investigate and provide anti-viral treatment for appropriate contacts of the case Advise on safety of animal/health care professionals Ensure retrieval of laboratory specimens Disinfect home Liaise with press Yes Is the suspected source an animal in the United Kingdom? No Liaise with MAFF Assess safety of workers Discuss with VRD CPHL/CAMR Discuss with local clinicians Liaise with CVO Trace animal overseas Inform DH/CDSC for follow up and animal tracing abroad Please note that this chart reflects public health control in England. For the devolved administrations, equivalent bodies should be notified where necessary 70. Key to abbreviations used in Figure 1: CCDC Consultant in Communicable Disease Control; CVO Chief Veterinary Officer; LA local authority; PHLS Public Health Laboratory Service; CDSC Communicable Disease Surveillance Centre; CPHL Central Public Health Laboratory; RE Regional Epidemiologist; DH Department of Health; HSE Health and Safety Executive; MAFF Ministry of Agriculture, Fisheries and Food; VRD Virus Reference Division; VLA Veterinary Laboratories Agency. 15

17 bg

18 Laboratory Containment Level 4 APPENDIX 1 Laboratory Containment Level 4 (Extract from Advisory Committee on Dangerous Pathogens (1995) Categorisation of biological agents according to hazard and categories of containment. Fourth edition. HSE Books. (ISBN )) Laboratory Containment Level 4 must be used for all work with biological agents in Hazard Group 4. 1 A detailed code of practice should be prepared for the laboratory and a safety officer should be appointed and be directly accountable to the person identified as responsible for the work. Personnel should be over the age of 18 and must be provided with suitable and sufficient information, instruction and training on working in the laboratory. The work should be closely supervised. A list must be kept of employees engaged in work with biological agents in Hazard Group 4 indicating the type of work done and, where known, the agent(s) to which they are exposed. This must include, as appropriate, a record of exposures (for example resulting from accidents and incidents). In general, this list must be kept for at least ten years but Schedule 3 in COSHH shows that for some infections an extended period of up to 40 years may be necessary. Specific requirements for Containment Level 4 laboratories 1 The laboratory must be separated from any other activities in the same building (see point 15 below). 2 The laboratory must be maintained at an air pressure negative to atmosphere (see point 23 below). Input air must be HEPA-filtered (or equivalent) and extract air double HEPA filtered (or equivalent) (see point 24 below). 3 Access to the laboratory must be restricted to authorised personnel and a key procedure established so that entry is restricted at all times. Entry must be through an airlock. 4 The laboratory must be sealable to permit disinfection (see point 31 below). 5 There must be specified disinfection procedures. 6 Efficient control measures must be taken against insect and rodent vectors. 7 The laboratory must be easy to clean. Bench surfaces, floors, walls, and ceilings must be impervious to water and resistant to acids, alkalis, solvents and disinfectants. 8 There must be secure storage of biological agents. 9 There must be an observation window or alternative so that the occupants can be seen. 10 The laboratory must contain its own equipment. 11 Infected materials must be handled in a Class III safety cabinet (see point 27 below), isolator or other suitable containment offering an equivalent level of protection. 12 There must an incinerator on site for the disposal of animal carcasses. 1 Some agents in this group may be pathogens of animals (see ACDP Categorisation, 1995, Appendix 20). Certain additional control measures specified by Agriculture Departments may be necessary to prevent their release to the environment. 17

19 Hendra Virus and Nipah Virus 13 Personal protective equipment, including protective clothing, must be: (a) (b) (c) stored in a well-defined place; checked and cleaned at suitable intervals; when discovered to be defective, repaired or replaced before further use. 14 Personal protective equipment which may be contaminated by biological agents must be: (a) (b) (c) removed on leaving the working area; kept apart from uncontaminated clothing and equipment; decontaminated and cleaned or, if necessary, destroyed. 15 The laboratory unit should be a separate building or form an isolated part of a building. 16 There should be adequate space (24m 3 ) in the laboratory for each worker. 17 The clean side of the airlock (see point 3 above) should be separated from the restricted ( dirty ) side by changing and showering facilities and preferably by interlocking doors. The outer door should be labelled with a work in progress sign. 18 At all times during work in the laboratory/laboratory suite or unit there should be a second competent person present to assist in the case of emergency. 19 High performance respiratory protective equipment (two or more units) should be available in the clean side of the laboratory unit for use in an emergency. 20 There should be a telephone or other means of outside communication in the laboratory/laboratory suite. 21 A complete change of clothing should be worn in the laboratory unit. After work is finished, clothing should be removed in the dirty side of the changing area and placed in a container for autoclaving. A shower should be taken before leaving the laboratory. 22 All effluent, including that from the shower, should be rendered safe before discharge. 23 The room in which the cabinet system is sited must be maintained at an air pressure negative to atmosphere. Atmosphere in this context may be taken to mean the external air and/or other parts of the laboratory suite or building depending on the circumstances. In effect, this means arranging engineering controls such that a continuous inward airflow into the laboratory is to be maintained but this is necessary generally only when work with biological agents is actually in progress. Provision should be made for comfort factors, i.e. supply of fresh air, temperature control. 24 The usual practice is to ventilate the laboratory unit through independent ducting by a plenum and a total-loss exhaust air system. The exhaust air from the laboratory and the cabinet/cabinet system (see point 27 below) must pass through two HEPA filters (or equivalent) mounted in series before it leaves the laboratory unit. Use of twin filters for incoming air is also recommended as an additional safeguard against filter or filter-seal failure. 25 A negative pressure of at least 70 Pascals (7 mm of water) should be maintained in the laboratory and a negative pressure of about 30 Pascals (3 mm of water) in the airlock. An alarm system should be fitted to detect any unacceptable change in air pressure and manometers should be displayed which can be read from both inside and outside the laboratory. 18

20 Laboratory Containment Level 4 26 The supply and extract airflows should be interlocked to prevent positive pressurisation of the laboratory in the event of a failure of extract fans. 27 In practice, a sophisticated cabinet system or cabinet line rather than a single Class III cabinet is generally used in order to provide the necessary space for working safely and having direct access to equipment such as a refrigerator, incubator and autoclave all of which are generally built into the structure. The system, therefore, amounts to a series of interconnected Class III safety cabinets with control and indicator devices built in. The integrity of such a complex installation must be most carefully and regularly monitored to ensure that there are no leaks and that the specification, and airflows through the system, are at least equivalent to those specified in BSEN 12469: There should be a programme of regular validation of the continuing safe operation of control systems (for example, checks on airflows, filter integrity, sensors, indicators, interlocks) coupled with routine servicing and maintenance of all safety equipment and plant. COSHH Regulation 9 in referring to maintenance, examination and test of control measures and specifically to local exhaust ventilation must be observed. This means for example, that HEPA filters and their fittings and seals must be thoroughly examined and tested at intervals not exceeding 14 months. In practice, depending on the frequency of use, these tests are commonly carried out at shorter intervals, for example, six monthly. 29 An emergency electricity supply should be provided to cut in automatically in the event of a power failure. 30 An additional ventilated airlock may be required for bringing in larger items of equipment that cannot pass through the personnel airlock or the autoclave. Larger equipment to be removed from the laboratory should not be passed through the airlock until the laboratory and the equipment in it has been decontaminated by fumigation or other measures appropriate to the circumstances. 31 COSHH requires that the Containment Level 4 laboratory is to be sealable to permit disinfection. While the definition of disinfection may be widely interpreted, in practice, it may be necessary to decontaminate by fumigating the accommodation when, for example, a major spillage has occurred or when maintenance work is to be carried out. 32 A double ended autoclave with interlocking doors with entry in the laboratory and exit in a clean area should be provided. It is preferable that the autoclave is built into the cabinet system. 33 Eating, chewing, drinking, taking medication, smoking, storing food and the application of cosmetics should be forbidden. 34 Mouth pipetting should be forbidden. 35 All infectious material must be stored in the laboratory unit and nowhere else. 36 All material should be made safe or safe to handle before removal from the laboratory. A double-ended dunk tank filled with an effective disinfectant, or a safe alternative system, may be required for the removal of materials that cannot be autoclaved. The methods chosen for the removal of infected materials, including all waste for incineration, should be authorised by the safety officer and specified in the local code of practice. If a dunk tank is used, it should be sealed during fumigation if the disinfectant it contains is likely to react with the fumigant to form toxic compounds. 37 All accidents and incidents (spills and other forms of exposures to infective materials) should be immediately reported to and recorded by the safety officer who should take the appropriate measures specified in the local code of practice, which must include the requirements for informing employees in accordance with Schedule 3 of the COSHH Regulations. 19

21 Hendra Virus and Nipah Virus High Security Infectious Disease Units and Laboratories High Security Infectious Disease Units and Patient Management Laboratories: Coppetts Wood Hospital Coppetts Road Muswell Hill London N10 1JN Tel: Newcastle General Hospital Westgate Road Newcastle-Upon-Tyne Tyne and Wear NE4 6BE Tel: APPENDIX 2 High Security Infectious Disease Viral Diagnostics Laboratories: Public Health Laboratory Service Virus Reference Division Central Public Health Laboratory Colindale Avenue London NW9 5HT Tel: Centre for Applied Microbiology and Research (CAMR) Porton Down Salisbury SP4 0JG Tel:

22 Transportation of Patients Transportation of Patients Ambulances APPENDIX 3 1. During transportation of patients, good ambulance practices and personal hygiene are the best defence against most infectious diseases. When these alone are not considered sufficient, specific instructions will be given by the senior medical officer at the HSIDU to ensure protection. This will normally be in accordance with the Ambulance Service Infectious Disease Procedure (Ambulance Category III) and the associated guidance. 2. Infectious diseases are classified by the Ambulance Service into three categories (I, II, III) according to the action necessary to safeguard ambulance staff during the ambulance transport. Moderate and highrisk patients, such as those known or suspected to be infected with Hendra or Nipah virus would be classified as Ambulance Category III. 3. Staff transporting patients must be qualified ambulance personnel, who should be adequately trained and practised in the procedure. 4. Regular training exercises with adjacent services and the designated HSIDU are recommended. General guidance for the transport of patients at Ambulance Category III. All Ambulance Category III removals will be taken to a HSIDU, or intermediate isolation facility, after consultation with the physician in charge. Ambulances need not be stripped down completely (resuscitation equipment, oxygen supply etc. should remain). A bag and mask should be used to resuscitate all patients with infectious disease. Under no circumstances should direct oral resuscitation be carried out. Chief Ambulance Officers should ensure that there are clear operational instructions in place, and that all staff, including Control Officers, are aware of: the possible routes of transmission of Hendra and Nipah virus; the importance of taking advice from the designated HSIDU on the provision of, and requirement for, personal protective clothing and, where necessary, patient isolators; arrangements for the journey to the designated HSIDU or intermediate isolation facility; arrangements for disinfection procedures for the ambulance, the crew s clothing, etc., and subsequent personal surveillance procedures. 21

23 Hendra Virus and Nipah Virus 5. In the case of long-distance journeys, an escort vehicle should be provided, but for most instances this will not be necessary. In the event of a vehicle breakdown, the crew should radio the ambulance control unit for a towing vehicle to be despatched. Under no circumstances should members of the crew who have been in contact with the patient leave the vehicle on route. The crew should proceed as directed to the entrance to the HSIDU, and once the patient has been handed over await instructions regarding disinfection and decontamination procedures. Air transportation within the UK 6. Whenever possible road transport should be used in preference to air transport. However, if unavoidable, ambulant and continent patients can travel by air ambulance with trained crews. For those patients who are not ambulant or continent, if the necessary facilities are available, an air transport isolator held by the RAF may transport them. Air ambulance crews should adopt the same protective precautions as road ambulance crews. International arrangements 7. It is generally accepted on public health grounds, that persons suffering from Hendra/Nipah virus infection should be treated locally rather than transported to areas where the diseases do not exist. Nevertheless, instances may arise where it becomes necessary to transport a confirmed or suspected Hendra or Nipah virus infected patient from an endemic to a non-endemic area. In these circumstances, it is essential to minimise the risk to those who come into contact with the patient as part of their work and to the general public health of the receiving country. Normally the air evacuation procedure of a UK national infected with Hendra or Nipah virus would be initiated by the Foreign and Commonwealth Office. The decision to evacuate would be taken in consultation with the DH, CDSC and those responsible for moving the patient. 8. If a case of suspected Hendra or Nipah virus infection is notified to a Port Health Authority, or if the Port Medical Officer has reason to suspect Hendra or Nipah virus infection in a crew member or passenger of an aircraft or ship, action should be taken to assess the patient and to transfer them to appropriate isolation facilities in the same way as if the patient were already in the country. If necessary the powers provided by the Public Health (Aircraft) Regulations 1979 or the Public Health (Ships) Regulations 1979 may be used. 1 1 In Northern Ireland the Public Health (Ships) Regulations (Northern Ireland) 1971 and the Public Health (Aircraft) Regulations (Northern Ireland) 1971 apply. 22