Hendra virus
National guidelines for public health units

The Series of National Guidelines have been developed in consultation with the Communicable Diseases Network Australia and endorsed by the Australian Health Protection Committee. Their purpose is to provide nationally consistent advice and guidance to public health units in responding to a notifiable disease event. These guidelines capture the knowledge of experienced professionals, built on past research efforts, and provide advice on best practice based upon the best available evidence at the time of completion.

Page last updated: 24 January 2012

PDF printable version of Hendra: National guidelines for public health units (PDF 184 KB)

Hendra SoNG V2.0 endorsed by CDNA: 9 Nov 2011
Noted by AHPC: 22 Dec 2011
Released by DoHA: 19 Jan 2012

The Series of National Guidelines have been developed in consultation with the Communicable Disease Network Australia and endorsed by the Australian Health Protection Committee. Their purpose is to provide nationally consistent advice and guidance to public health units (PHUs) in responding to a notifiable disease event. These guidelines capture the knowledge of experienced professionals, built on past research efforts, and provide advice on best practice based upon the best available evidence at the time of completion.

The guidelines are necessarily general and readers should not rely solely on the information contained within these guidelines. The information contained within these guidelines is not intended to be a substitute for advice from other relevant sources including, but not limited to, the advice from a health professional. These guidelines are intended for information purposes only. The membership of the Communicable Disease Network Australia (‘CDNA’) and the Commonwealth of Australia (‘the Commonwealth’), as represented by the Department of Health and Ageing, does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, or process disclosed at the time of viewing by interested parties.

The CDNA and the Commonwealth expressly disclaim all and any liability to any person, in respect of anything and of the consequences of anything done or omitted to be done by any person in reliance, whether in whole or in part, upon the whole or any part of the contents of this publication.

1. Summary

Public health priority

Urgent.

Case management

  • Respond to a confirmed human case immediately on notification
    • Ensure appropriate infection control measures are in place.
    • Ensure that liaison with an infectious disease physician occurs
  • Respond to a confirmed equine case, or where heightened suspicion of infection in a horse exists as advised by the relevant animal health agency, immediately on notification.
  • Ensure appropriate infection control measures are in place.
  • Establish a team, including public affairs officer, to manage the public health response for any confirmed human or equine case.
  • Close liaison with animal health agencies is necessary – joint meetings should be held with relevant state or territory animal health agencies to ensure a coordinated response. Initial meeting should be held within 24 hours of notification.

Contact management

  • Assess exposure.
  • If high exposure to body fluids of a confirmed equine case, refer as soon as practicable to an infectious diseases physician for consideration of post-exposure prophylaxis.
  • Advise all contacts to seek early medical advice if they develop fever, respiratory or neurological symptoms within three weeks of exposure.

2. The disease

Infectious agents

Hendra virus (previously called equine morbillivirus) is a paramyxovirus of the genus Henipavirus. The only other agent in this genus is Nipah virus.

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Reservoir

Fruit bats (Pteropus species), also known as flying foxes, are the only known natural reservoir. The distribution of flying fox species in Australia is shown in Figure 1. All species are susceptible – antibody to Hendra virus has been found in 20-50 percent of flying foxes in mainland Australian populations.12 Since 1994, widespread testing involving 46 other species of animals and arthropods has not shown the natural presence of the virus in any species other than flying foxes.
Figure 1: Distribution of Pteropus species (flying foxes) on mainland Australia3
    Map of Australia showing Distribution of Pteropus species (flying foxes) on mainland


    Horizontal hatching = P. alecto (black flying fox)
    Vertical hatching = P. poliocephalus (grey headed flying fox)
    Solid black = P. conspicillatus (spectacled flying fox)
    Broken line = southern inland limit of P. scapulatus (little red flying fox)

    * Note that flying foxes are nomadic animals and changes in distribution may occur, e.g. the range of grey headed flying foxes has historically extended west into parts of South Australia including Adelaide on a periodic basis



    Mode of transmission

    Bat-to-horse

    Spillover from flying foxes to horses is rare (32 documented events from 1994 to October 2011, 9 in NSW and 23 in Queensland), possibly occurring through contamination of horse-feed by infectious fluids from bats, e.g. bat urine/reproductive products. At the time of the original outbreak at Hendra (in Brisbane, Queensland) in 1994, testing of nearly 2,000 horses across Queensland, including 906 within 1 km of the quarantined properties found no seropositive horses apart from those on the quarantined premises, i.e. no evidence of other spillover events.4

    Horse-to-person

    Only seven human cases have been documented (as of September 2011). All seven had a high level of exposure to respiratory secretions and/or other body fluids of horses subsequently diagnosed with Hendra virus infection, or presumed to have Hendra virus infection through review of clinical/epidemiological evidence in the absence of samples for laboratory testing. Three of the cases were exposed to tissues during post mortem examinations on those horses. Two were probably exposed while performing nasal cavity lavage in the days immediately before the horse showed any clinical signs of disease. Further details on these cases are presented in Appendix 1. No cases have been documented in people with medium or lower exposure levels, including anyone appropriately using personal protective equipment,5 and not all people with high exposures have become infected. On the evidence available, the most likely mode of transmission is via substantial direct exposure of mucous membranes (or non-intact skin) to respiratory secretions (including large droplets) or blood from an infected horse. Indirect exposure to respiratory secretions or blood, and direct or indirect exposure to other body fluids, may contribute to overall transmission risk. Current evidence does not support airborne exposure as a significant mode of transmission.

    Horse-to-horse

    Has mainly occurred in situations of close contact. Transmission between horses has been more efficient in stabled situations, with spread between multiple horses occurring in all stabled situations to date – Hendra (1994), Redlands (2008) and Cawarral (2009), all in Queensland (see Appendix 1). It is possible that short-term survival of Hendra virus on environmental surfaces and inadvertent human-assisted fomite transmission (e.g. horse gear or veterinary equipment contaminated with secretions or fluids of an infected horse) may contribute to more efficient transmission in stabled situations. Of the 20 equine cases associated with the 1994 outbreak in Hendra, 18 were from the index property and the other two were from the immediately adjacent property.

    Bat-to-person

    No evidence that this occurs. A study of 128 bat carers, the majority of who reported daily contact with bats and/or a history of bat bites, found no individuals with antibodies to Hendra virus.6

    Person-to-person

    No evidence that this occurs. Serological testing in 169 health care worker contacts and four household contacts of the first three human cases found no individuals with antibodies to Hendra virus.7Testing of contacts of the subsequent four human cases also produced uniformly negative results.8 However it is desirable to avoid close contact with respiratory secretions and other body fluids of symptomatic human cases. Standard, contact and droplet precautions9 should be implemented for management of suspected or confirmed human cases.

    Person-to-horse

    No evidence that this occurs. However it is desirable for suspected human cases to avoid close contact with horses until the diagnosis has been clarified.

    Experimental

    Disease has been induced under experimental conditions in cats, ferrets, hamsters, guinea pigs, horses and pigs. Experimentally infected horses can excrete viral RNA in nasal secretions for at least two days before showing clinical signs of disease.510 This underpins recommendations that any procedures on apparently healthy horses that may cause aerosolisation or splashes should be performed with appropriate infection control precautions including personal protective equipment.

    Other

    A single dog developed antibodies to Hendra virus on a property where three horses developed Hendra virus infection in July 2011. Although the source of exposure for the dog cannot be definitively ascertained, horse-to-dog transmission is the most plausible scenario given the dog had potential opportunity for exposure to infected horses. There is no evidence that bat-to-dog or dog-to-person or dog-to-horse transmission occurs.

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    Incubation period

    Humans

    Current limited evidence suggests that the incubation period in humans is between 5 and 21 days.

    Horses

    The incubation period in horses appears to be 5-16 days, although the incubation period in one horse in the 2009 Bowen event may have been 31 days (personal communication, Steven Donohue [Queensland Health] and Hume Field [Biosecurity Queensland] November 2009).

    Infectious period

    Humans

    Unknown in humans, as no evidence of person-to-person transmission to date. While the risk of transmission is probably negligible, for public health purposes human cases should be considered potentially infectious while symptomatic.

    Horses

    For human public health purposes, horses should be considered potentially infectious from 72 hours prior to onset of clinical signs of disease until death (by disease or euthanasia) and safe disposal of the carcase.5 Careful assessment is required of how closely the horse was observed for the onset of illness. It is unclear whether horses recovered from illness are infectious or are capable of permanently clearing the virus.

    Clinical presentation and outcome

    Humans

    The documented human cases to date have presented with:
    • self-limiting influenza-like illness (two cases)
    • influenza-like illness complicated by severe pneumonic illness contributing to death (one case)
    • aseptic meningitis with apparent recovery, then death from encephalitis 13 months later (one case)
    • acute influenza-like illness followed by encephalitis and seroconversion, followed by recovery (one case) and death (two cases).
    Further detail on these seven cases is included in Appendix 1.

    No cases of asymptomatic infection have been identified from extensive testing of human contacts associated with Hendra virus events up to September 2011.

    Horses

    In horses, Hendra virus has a clear predisposition for targeting endothelial cells of blood vessels, with clinical signs dependent on the sequence in which organs are affected. Documented equine cases to date have typically presented with acute onset of clinical signs, including increased body temperature and increased heart rate, and rapid progression to death associated with either respiratory or neurological signs or a mix of these; some horses have also shown evidence of multi-organ involvement. The clinical signs, particularly of early Hendra disease, may be non-specific, although progression from onset to death is typically rapid, over a couple of days. Less severe infections have been identified in horses being monitored during an outbreak; these horses are typically second or third generation cases. From figures to date, approximately 75% of infected horses can be expected to die. Those that survive often have mild signs and seroconvert during the recovery period. The current AUSVETPLAN policy for Hendra virus infection prescribes euthanasia for all horses that test positive,11 as they may be infectious or relapse and become infectious. Refer to the Biosecurity Queensland Guidelines for veterinarians handling potential Hendra virus infection in horses5 for more information on clinical presentation.

    Persons at increased risk of disease

    People who are more likely to be exposed to infected horses may be at increased risk e.g. veterinarians, horse trainers, stable workers.

    Disease occurrence and public health significance

    The number of equine and human cases in the 32 events known to have occurred up to September 2011 are summarised in Appendix 1. All of these events have occurred in Queensland or New South Wales. However given the distribution of flying foxes (Figure 1) and frequency of horse movements between states and territories, cases could occur anywhere in Australia.

    3. Routine prevention activities

    • Veterinary practitioners and staff handling confirmed or suspected equine cases or conducting post mortem examinations on the carcase of a confirmed or suspected case should wear appropriate personal protective equipment and take preventive hygiene measures (refer to the Biosecurity Queensland guidelines for veterinarians handling potential Hendra virus infection in horses5).
    • Horse owners or carers should minimise unnecessary human contact with sick horses and take appropriate preventive hygiene measures (refer to the Workplace Health and Safety Queensland document Hendra virus - information for horse properties and other horse related businesses12).
    • Horse owners and carers can take steps to protect horses from becoming infected with Hendra virus by reducing exposure to bats, e.g. by placing feed bins and water troughs under cover and away from areas where bats feed or roost (refer to the Workplace Health and Safety Queensland document Hendra virus - information for horse properties and other horse related businesses12 and the Queensland Horse Council website at http://www.qldhorsecouncil.com/default.aspx).

    4. Surveillance objectives

    • To identify equine and human cases so that appropriate contact tracing and public health measures can occur.
    • To collect information about new human cases in order to broaden understanding of this high profile emerging infectious disease.
    Surveillance for equine cases is primarily the responsibility of animal health agencies. Appropriate processes should be in place to ensure relevant surveillance information is shared promptly at state and territory level between animal and human health agencies.

    5. Data management

    In states and territories where Hendra virus infection is notifiable, confirmed human cases should be entered onto the notifiable diseases database, ideally within one working day following notification.

    6. Communications

    • As soon as practicable and ideally within one hour of notification, notify the state or territory communicable diseases branch (CDB) of confirmed human or equine cases.
    • As soon as practicable and ideally within four hours of notification, state/territory CDB should notify the relevant animal health agency of any confirmed human case.
    • As soon as practicable and ideally within one working day, the state/territory CDB should notify case details and response plan to the CDNA secretariat.

    7. Case definition

    Hendra virus infection in humans is not currently nationally notifiable and there is no national case definition. The following is based on the Queensland case definition as of October 2011.

    Confirmed case

    A confirmed case requires laboratory definitive evidence
    OR
    laboratory suggestive evidence and epidemiological evidence and clinical evidence.

    Laboratory definitive evidence

    Isolation of Hendra virus
    OR
    detection of Hendra virus by nucleic acid testing

    Laboratory suggestive evidence

    Detection of antibody to Hendra virus by microsphere immunoassay, confirmed by specific immunofluorescent assay
    OR
    Detection of antibody to Hendra virus by virus neutralisation test

    Epidemiological evidence

    Exposure, within 21 days prior to onset of symptoms, to a horse with confirmed Hendra virus infection, or where heightened suspicion of Hendra virus infection exists as advised by the relevant animal health agency.

    Clinical evidence

    Clinically compatible acute illness (see clinical presentation section above)

    NB: For case definitions in horses see Guidelines for veterinarians handling potential Hendra virus infection in horses. Biosecurity Queensland, 2010. Available at: http://www.dpi.qld.gov.au/4790_13371.htm

    8. Laboratory testing

    Human testing may be indicated when:
    • There has been exposure to confirmed or suspected equine cases; or
    • There is compatible human illness and testing is performed after consultation with an infectious diseases physician.
    As of October 2011, Queensland Health Forensic and Scientific Services (QHFSS) is the only human health laboratory in Australia able to test for Hendra virus. Tests available include nucleic acid testing (NAT) and serology. Virus isolation is usually attempted on acute phase specimens, particularly when NAT is positive.

    Testing of human samples is also available, on request, from the Australian Animal Health Laboratory (AAHL) in Geelong, and may be available on request from some state animal health laboratories. Tests available from AAHL include NAT, virus isolation and virus neutralisation test (VNT).

    Nucleic acid testing

    NAT can be performed on respiratory samples (deep nasal swab or nasopharyngeal aspirate), serum (preferable to blood), cerebrospinal fluid, urine and tissue samples.

    Minimum CSF, serum, liquid respiratory or urine sample volume is 0.5ml.

    Tissue samples (minimum rice grain size) should be in viral transport medium, not fixed. Respiratory swab samples should be in viral transport medium. Chill all samples immediately upon collection (4oC) and transport cool (4oC), not frozen, within 24 hours.

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    Serology

    QHFSS currently performs a screening microsphere immunoassay (MIA) for IgM and IgG and has the capability of differentiating individuals with natural antibodies from those administered therapeutic monoclonal antibodies. If positive, this is followed by a confirmatory immunofluorescence assay (IFA) that can be quantified. As with all serological tests, false positive results can occur. If MIA and IFA are positive in the absence of positive NAT, and there is any question as to whether this represents true infection, specimens may be referred to AAHL for VNT. Where serological testing is indicated, a baseline sample should ideally be collected as early as possible after exposure and stored for testing in parallel with subsequent samples. Minimum sample volume of CSF or serum is 0.2ml. Transport cool (4oC) within 24 hours.

    The earliest laboratory evidence of infection in human Hendra virus cases has been positive nucleic acid testing in blood, respiratory specimens, then urine, with serology becoming positive two to five days after onset of symptoms.

    Recommendations:

    For suspected human cases
    • As a minimum, collect blood and urine for NAT.
    • Additional tests, depending on clinical picture may include deep nasal swab, nasopharyngeal aspirates and/or CSF for NAT. Tissue samples can be collected post-mortem (or by pre-mortem biopsy where relevant) for NAT.
    • Serology should be considered whenever there is a high index of suspicion (e.g. high level exposure to a confirmed equine case) or where NAT could potentially be less reliable e.g. due to duration of symptoms greater than one week.
    For human contacts of an equine case
    • If high exposure level, collect baseline serology and store for testing in parallel with follow up samples at 3 and 6 weeks after last exposure.
    • If medium or lower exposure level, assess if symptoms develop and test as for suspected cases above where indicated.

    9. Case management

    Response times

    Commence investigation immediately on notification of a confirmed human or equine case, or where notified by an animal health agency of heightened suspicion of infection in a horse on clinical and epidemiological grounds.

    Response procedure

    Case investigation – confirmed or suspected equine case

    On notification of a confirmed equine case, or where an animal health agency has heightened suspicion on clinical and epidemiological grounds:
    • Liaise with the animal health agency to:
      • Ensure appropriate infection control measures5 including cessation of other than absolutely necessary human contact are in place for all confirmed equine cases and any horses that have been in contact with equine cases.
      • Clarify timeline for results of laboratory testing when not already confirmed.
      • Establish whether/what communication has occurred with potential human contacts.
    • Identify and manage human contacts.

    Case investigation – confirmed or suspected human case

    On notification of a confirmed human case, or where a public health unit considers there is heightened suspicion on clinical and epidemiological grounds:
    • Liaise with the treating clinician to:
      • Ensure appropriate infection control measures (see Isolation and Restriction section below) are in place.
      • Ensure liaison with an infectious diseases physician occurs.
    • Facilitate urgent laboratory testing where not already confirmed.
    • Identify any exposures to known equine cases, and other equine exposures where relevant.
    • Identify and manage human contacts.
    • Liaise with senior staff in the relevant state or territory animal health authority to:
      • Alert them to the human case.
      • Discuss need for testing of relevant horses, where appropriate.
      • Establish whether/what communication has occurred with potential human contacts of relevant horses.

    Response management – confirmed equine or human case

    For all confirmed human or equine cases, a team should be established to manage the public health response. Involve a public affairs officer early and develop clear and consistent public messages. Unless the event is confined to a small property and there are very few human contacts the public health actions are likely to be resource intensive for several weeks.

    Close liaison with the relevant state or territory animal health agency is necessary and regular interagency meetings should be held to ensure a coordinated response. The initial meeting should be held within 24 hours of notification. Relevant state or territory workplace health and safety agencies should be involved early if the event occurs in a workplace.

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    Case treatment

    Responsibility of the treating medical practitioner. Advice should be sought from an infectious diseases physician.

    Education

    Cases should be informed about the nature of infection, mode of transmission and other relevant information. Refer to general fact sheet for disease (Appendix 2).

    Isolation and restriction

    • While there is no evidence of human to human transmission, standard, contact and droplet precautions9 should be applied for symptomatic persons suspected or known to be infected with Hendra virus. Additional precautions may be ordered at the discretion of the treating infectious diseases physician.
    • Confirmed cases, for the duration of acute illness, should avoid close contact with animals.
    • Confirmed cases should never subsequently donate blood or any other tissue, even if they fully recover.

    10. Environmental evaluation

    Measures to ensure the cessation of further inadequately protected equine or human contact with confirmed or potential equine cases on an affected property are the responsibility of the relevant state or territory animal health agency. As per the Biosecurity Queensland guidelines for veterinarians handling potential Hendra virus infection in horses,5 such measures include isolation/euthanasia of infected horses with appropriate disposal of carcases, and quarantine of horses from relevant properties. A log of people visiting or working on the property should be maintained by the animal health agency.

    In human health care facilities environmental cleaning procedures should be conducted in accordance with Australian infection control guidelines.9

    11. Contact management

    Identification of contacts

    The aim of identifying contacts is to:
    • Assess their exposure and provide advice about their level of risk and other relevant information.
    • Refer for consideration of post-exposure prophylaxis where appropriate.

    Contact definition

    Contact of equine case


    People who have had direct or indirect exposure of skin or mucous membranes to body fluids of a horse determined by the relevant state or territory animal health agency to be a confirmed case of Hendra virus infection,5 or of a horse where heightened suspicion of infection exists on clinical and epidemiological grounds as advised by the relevant animal health agency.

    Contact of human case

    • People who have had close contact with a symptomatic confirmed human case or person where heightened suspicion of infection exists on clinical and epidemiological grounds as determined by the relevant public health unit (including household or household-like contacts, sexual partners, and anyone with direct or indirect exposure of skin or mucous membranes to body fluids).

    Investigation

    Exposure assessments of human contacts are required in relation to all confirmed equine cases of Hendra virus infection, and where heightened suspicion of infection in a horse exists on clinical and epidemiological grounds as advised by the relevant animal health agency. Exposure assessment of human contacts of confirmed human cases is also recommended – although risk is generally likely to be negligible, assessment and reassurance will often be of benefit.

    Obtain from relevant state or territory animal health agency information on all horses with confirmed Hendra virus infection, and any epidemiologically linked equine cases where heightened suspicion of Hendra virus infection exists on clinical and epidemiological grounds (this may include previously sick horses associated with affected properties). ‘Trace back’ investigations by the animal health agency of horse movements from affected properties may generate considerable workload for public health units by identifying other humans requiring follow up as contacts of additional equine cases.

    Urgent priorities are to obtain a line listing of all people who may have been in contact with confirmed equine cases, or where heightened suspicion of infection in a horse exists on clinical and epidemiological grounds as advised by the relevant animal health agency (contacts of human cases are a lower priority as they are likely to be at negligible risk), and then to:
    • Assess exposure (using exposure assessment form, Appendix 4) and current health status.
    • If high exposure to body fluids of a confirmed equine case, liaise with an infectious diseases physician as soon as practicable for consideration of post-exposure prophylaxis.
    • If assessed as medium exposure, discuss as soon as practicable with other appropriately experienced public health practitioners and infectious diseases physician/s to reach consensus on exposure assessment.
    • Refer any symptomatic people to appropriate care.
    • Provide information about Hendra virus.
    • Counsel about risk.
    • Provide advice about testing recommendations (see Laboratory Testing section above).
    • Provide advice about self-monitoring of their health, and to seek early medical advice if they develop fever or respiratory or neurological symptoms within three weeks of exposure, phoning ahead of the visit so that appropriate infection control measures can be put in place (see ‘Isolation and Restriction’ section and fact sheet for contacts ‘Hendra virus – information for people who have been exposed to a horse or human infected with Hendra virus’ – Appendix 3).
    The urgency of response to illness in contacts depends on the assessed level of exposure; clinically compatible illness (respiratory or neurological symptoms) in a person with high exposure to body fluids of an equine case should be urgently assessed by an infectious diseases physician.

    Instructions for exposure assessment:
    • It is best to refer to horses by their popular (or most commonly used) name, to minimise confusion.
    • Determine the level and type of contact between the person and the equine (or human) case/s.
    • Assessment of exposure should review activities with any equine cases up to three days prior to the onset of illness in the horse, and with symptomatic human cases.
    • Reinterviewing contacts of equine cases may identify useful new information.
    As psychological stress and exacerbation of existing health issues can occur due to a Hendra virus event, people involved in the event should be strongly encouraged to access their usual health care practitioner to assess need for ongoing physical and psychological support, medical or workers compensation certification and referral to other services as necessary (see below). GPs should be provided with appropriate information and resources and public health unit contact details. Initial contact with GPs should preferably be by telephone where feasible.

    Prophylaxis

    No drug or product is of proven benefit in humans, although monoclonal antibodies show the most promise (as of October 2011). Monoclonal antibodies have been shown to protect ferrets from serious disease when given 10 hours after exposure to Nipah virus13 and when given 10-12 hours after exposure to Hendra virus (personal communication, Deborah Middleton, CSIRO, 20 September 2011). They have also been shown to protect African green monkeys from severe fatal infection when given 72 hours after exposure to a lethal dose of Hendra virus.14 As the evidence base to inform use of PEP is rapidly evolving, and relates to small scale in vitro and animal model studies and empirical experience in exposed humans, the infectious disease physician (IDP) involved should consult with other IDPs who have experience in Hendra PEP and knowledge of the current evidence base. Wherever possible, an expert panel of public health practitioners and IDPs with appropriate experience should be convened as part of the incident management process to review all contacts identified as high and medium exposures and advise on provision of monoclonal antibody and logistic issues. The only stock of monoclonal antibodies, as of October 2011, is held in Queensland. Access to this stock for contacts with high level exposures can be sought via the Senior Director, Communicable Diseases Branch, Queensland Health.

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    Education

    Provide information about the disease to all contacts of confirmed human and equine cases, and contacts of horses or humans where heightened suspicion of infection exists on clinical and epidemiological grounds, as respectively advised by the relevant animal health agency or determined by the relevant public health unit.

    If an equine case is confirmed, it may be appropriate for human health agency officers to visit the property to provide information and support to key people (e.g. owners and managers), and to assist animal health agency staff in providing information to the local community. Any site visit should complement and not delay the full public health response, which focuses on the timely assessment of exposure and current health status of all people who may have been exposed to infected horses, including animal health practitioners, many of whom may not be available on site.

    A Hendra event can be extremely stressful for people exposed or otherwise involved. Contributors to the stress responses include:
    • Hendra is a rare disease with high mortality rate.
    • It is poorly understood with no proven treatment or prophylaxis.
    • It is subject to intense and sensationalist media scrutiny.
    • The disease is unfamiliar to GPs and local health practitioners.
    • It is subject to widespread myths and online misinformation.
    • The potential for devastating effects on the business/livelihood of those involved.
    • The death or euthanasia of horses and, rarely, other animals.
    Horse owners are likely to see animal health agency staff with high level personal protective equipment e.g. full length splash-proof overalls, face shields and respirators. Despite reassurance that these are conservative precautions, they may still infer incorrectly that Hendra virus is highly infectious and that they are at high risk of infection and death.

    Therefore, contacts and other closely involved persons, such as family members, owners, and others who may have minimal exposure, may require repeated reassurance and information.

    Isolation and restriction

    • No restrictions are required on the movements or activities of asymptomatic human contacts of an infected animal or human.
    • Symptomatic contacts should be managed with standard, contact and droplet<sup>]9 precautions.
    • Contacts of an infected animal or human should not donate blood or any other tissue until cleared by absence of illness over three weeks since last exposure (and negative test results where indicated).

    12. Special situations

    Nil

    13. References and additional sources of information

    1. Australian Biosecurity CRC for Emerging Infectious Disease. Hendra virus research [updated 2009; cited 4 Nov 2010]. Available from:
    2. Field H. The ecology of Hendra virus and Australian bat lyssavirus [PhD thesis]. University of Queensland, 2004. Available at: http://espace.library.uq.edu.au/eserv/UQ:13859/field_thesis_05.pdf
    3. Hall L, Richards G. Flying foxes: Fruit and Blossom Bats of Australia. University of New South Wales Press Ltd: Sydney 2000.
    4. Murray K, Rogers R, Selvey L, Selleck P, Hyatt A, Gould A, et al. A novel morbillivirus pneumonia of horses and its transmission to humans. Emerg Infect Dis; 1995, 1(1):31-33.
    5. Biosecurity Queensland. Guidelines for veterinarians handling potential Hendra virus infection in horses. Brisbane, 2011. Available from: http://www.dpi.qld.gov.au/4790_13371.htm" http://www.dpi.qld.gov.au/4790_13371.htm
    6. Selvey L, Taylor R, Arklay A, Gerrard J. Screening of Bat Carers for Antibodies to Equine Morbillivirus. Commun Dis Intell; 1996, 20(22):477-78.
    7. McCormack JG, Allworth AM, Selvey LA, Selleck PW. Transmissibility from horses to humans of a novel paramyxovirus, equine morbillivirus (EMV). J Infect; 1999, 38(1):22-3.
    8. Playford EG, McCall B, Smith G, Slinko V, Allen G, Smith I, et al. Human Hendra virus encephalitis associated with equine outbreak, Australia, 2008. Emerg Infect Dis; 2010, 16(2):219-23.
    9. National Health and Medical Research Council. Australian Guidelines for the Prevention and Control of Infection in Healthcare. Canberra, 2010. Available from: http://www.nhmrc.gov.au/guidelines/publications/cd33
    10. Middleton D. Initial experimental characterisation of HeV (Redland Bay 2008) infection in horses. CSIRO: 2009. Available from: http://www.dpi.qld.gov.au/documents/Biosecurity_GeneralAnimalHealthPestsAndDiseases/HeV-Initial-experimental-characterisation.pdf
    11. Primary Industries Ministerial Council. AUSVETPLAN Response Policy Briefs. 2009. Available from: http://www.animalhealthaustralia.com.au/wp-content/uploads/2011/04/RPB3.3-05FINAL27Jul11.pdf
    12. Workplace Health and Safety Queensland. Hendra virus - Information for horse properties and other horse related businesses. [updated June 2010; cited 10 August 2011]. Available from: http://www.deir.qld.gov.au/workplace/publications/alerts/hendra_virus_horse/index.htm
    13. Bossart KN, Zhu Z, Middleton D, Klippel J, Crameri G, Bingham J, et al. A Neutralizing Human Monoclonal Antibody Protects against Lethal Disease in a New Ferret Model of Acute Nipah Virus Infection. PLoS Pathog; 2009, 5(10):e1000642.
    14. Bossart KN, Geisbert TW, Feldmann H, Zhu Z, Feldmann F, Geisbert JB, et al. A neutralizing human monoclonal antibody protects african green monkeys from hendra virus challenge. Sci Transl Med; 2011, 3(105):105ra03.
    15. Selvey L, Wells RM, McCormack J, Ansford A, Murray P, Rogers R, et al. Infection of humans and horses by a newly described morbillivirus. Med J Aust; 1995, 162:642-45.
    16. O'Sullivan JD, Allworth AM, Paterson DL, Snow TM, Boots R, Gleeson LJ, et al. Fatal encephalitis due to novel paramyxovirus transmitted from horses. Lancet; 1997, 349(9045):93-5.
    17. Hanna JN, McBride W, Brookes DL, Shield J, Taylor CT, Smith IL, et al. Hendra virus infection in a veterinarian. Med J Aust; 2006, 185(10):562-64.

    14. Appendices

    Appendix 1 – Summary of human cases of Hendra virus infection and Hendra virus infection events, 1994-2011 (as at October 2011).
    Appendix 2 – General fact sheet
    Appendix 3 – Fact sheet for contacts
    Appendix 4 – Exposure assessment form – see separate form
    Appendix 5 – PHU checklist

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    15. Jurisdiction specific issues

    Links to State and Territory Public Health Legislation, the Quarantine Act and the National Health Security Act 2007.

    http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-state-legislation-links.htm

    Appendix 1 – Summary of human cases of Hendra virus infection and Hendra virus infection events, 1994-2011 (as at October 2011).



    Case 1 and 2
    In Hendra (a suburb of Brisbane) in 1994, a 49 year old horse trainer died after a fulminating pneumonic illness, and a 40 year old stable worker survived an influenza-like illness. These two cases occurred following a sudden outbreak of an acute respiratory syndrome among thoroughbred horses in a training complex. Both human cases had extensive close contact with respiratory secretions and other body fluids of several very ill horses.15 The incubation periods of the two cases were estimated to be five and six days. Surveillance of about 90 other people exposed to infected horses identified no other human cases.15

    Case 3
    In Mackay, north Queensland, in 1995, a 36 year old horse trainer died from severe encephalitis caused by Hendra virus. Subsequent investigations indicated he had been exposed to Hendra virus 13 months earlier whilst assisting a veterinarian to undertake a post mortem examination on two horses. He also had direct ante-mortem exposure to their respiratory secretions.16 (personal communication, Simon Bewg, Biosecurity Queensland, September 2006) Of note, he was hospitalised with aseptic meningitis shortly after exposure to the horses, with recovery at the time. This is considered to have been a seroconversion illness. The veterinarian who conducted the post mortem examination remained well.

    Case 4
    In Cairns, north Queensland, in late 2004, a veterinary practitioner aged in her 20s performed a post mortem examination on a horse subsequently presumed, based on clinical and epidemiological evidence, to have died of Hendra virus infection. The veterinarian had also attended to the horse in the last few minutes of its life and was extensively exposed to respiratory secretions and blood. About seven days later she developed a mild influenza-like illness and showed evidence of seroconversion to Hendra virus. At follow up four years later she remained well. Three other people who were also exposed remained well and did not seroconvert.17

    Case 5 and 6
    In July 2008, a veterinary hospital at Redlands (a suburb of Brisbane) was quarantined after four horses with neurological signs tested positive to Hendra virus. Another horse developed infection while under quarantine. Two of the staff members caring for the horses developed an acute influenza-like illness followed by encephalitis at seroconversion to Hendra virus. One of them subsequently died. One case was exposed during post mortem examination of a horse subsequently confirmed as infected with Hendra virus (possible 16 days incubation period) and both cases were exposed while performing nasal cavity lavage in the days immediately before the onset of clinical signs of disease in another horse (possible incubation periods of nine and 11 days).8

    Case 7
    In August 2009 at an equine nursery at Cawarral near Rockhampton, central Queensland, a 55 year old veterinarian performed a nasal endoscopy on a horse that was subsequently presumptively diagnosed (based on both clinical signs and exposure to a laboratory-confirmed equine case) with Hendra virus infection. The procedure was performed without respiratory protection or gloves while the horse had a fever and respiratory distress. Endoscopic examination showed visible petechiae and ecchymoses in the respiratory tract. The veterinarian was given a five-day course of ribavirin from day 14 post-exposure but developed an influenza-like illness 21 days post exposure followed by encephalitis and death. Three other people with extensive exposure to the blood and respiratory secretions of the horse (and a second horse involved in the same outbreak and confirmed as having Hendra virus infection) remained well and did not seroconvert. These three people were also given ribavirin prophylaxis.

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    Table: Summary of Hendra virus infection events with numbers of equine cases, and human cases and deaths, 1994-2011 (to October 2011).

    LocationState/TerritoryMonthYearHorsesHumansHuman deaths
    MackayQueenslandAugust
    1994
    2
    1
    1
    HendraQueenslandSeptember
    1994
    20
    2
    1
    CairnsQueenslandJanuary
    1999
    1
    0
    0
    CairnsQueenslandNovember
    2004
    1
    1
    0
    TownsvilleQueenslandDecember
    2004
    1
    0
    0
    PeachesterQueenslandJune
    2006
    1
    0
    0
    MurwillumbahNew South WalesOctober
    2006
    1
    0
    0
    PeachesterQueenslandJune
    2007
    1
    0
    0
    Clifton BeachQueenslandJuly
    2007
    1
    0
    0
    RedlandsQueenslandJune-July
    2008
    5
    2
    1
    ProserpineQueenslandJuly
    2008
    3
    0
    0
    CawarralQueenslandAugust
    2009
    4
    1
    1
    BowenQueenslandSeptember
    2009
    2
    0
    0
    TewantinQueenslandMay
    2010
    1
    0
    0
    BeaudesertQueenslandJune
    2011
    1
    0
    0
    WollongbarNew South WalesJuly
    2011
    2
    0
    0
    BoonahQueenslandJuly
    2011
    3
    0
    0
    Park RidgeQueenslandJuly
    2011
    1
    0
    0
    MacksvilleNew South WalesJuly
    2011
    1
    0
    0
    LismoreNew South WalesJuly
    2011
    1
    0
    0
    KurandaQueenslandJuly
    2011
    1
    0
    0
    BoondallQueenslandJuly
    2011
    1
    0
    0
    Logan ReserveQueenslandJuly
    2011
    1
    0
    0
    Hervey BayQueenslandJuly
    2011
    1
    0
    0
    ChinchillaQueenslandJuly
    2011
    1
    0
    0
    MullumbimbyNew South WalesJuly
    2011
    1
    0
    0
    BallinaNew South WalesAugust
    2011
    1
    0
    0
    MullumbimbyNew South WalesAugust
    2011
    1
    0
    0
    South BallinaNew South WalesAugust
    2011
    2
    0
    0
    North BallinaNew South WalesAugust
    2011
    1
    0
    0
    Currumbin ValleyQueenslandAugust
    2011
    1
    0
    0
    BeachmereQueenslandOctober
    2011
    2
    0
    0
    Total: 32
    66
    7
    4



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    Appendix 2 – General fact sheet
    Hendra Virus

    What is Hendra virus?

    • Hendra virus is a virus that infects large fruit bats (flying foxes).
    • Occasionally the virus can spread from flying foxes to horses and horses can then pass the infection on to humans. A small number of people who have had very close contact with infected horses have developed Hendra virus infection.
    • A single dog showed evidence of exposure to Hendra virus on a property where three horses developed infection in July 2011.
    • There is no evidence of Hendra virus occurring naturally in any other species.
    • Hendra virus was discovered following an outbreak of illness in a large racing stable in the suburb of Hendra, Brisbane in 1994.

    What are the symptoms?

    Hendra virus signs in horses

    • Hendra virus can cause a range of signs in horses. Usually there is a rapid onset of illness, fever, increased heart rate and rapid deterioration with respiratory and/or neurological (nervous system) signs. For more information on Hendra virus infection in horses, refer to state animal health agency websites at www.dpi.nsw.gov.au and www.dpi.qld.gov.au/home.htm

    Hendra virus signs and symptoms in people

    • Symptoms typically develop between 5 and 21 days after contact with an infectious horse.
    • Fever, cough, sore throat, headache and tiredness are common initial symptoms. Meningitis or encephalitis (inflammation of the brain) can develop, causing headache, high fever, and drowsiness, and sometimes convulsions and coma.
    • Hendra virus infection can be fatal.

    How is it spread?

    • It is thought that horses may contract Hendra virus infection from eating food recently contaminated by flying fox urine, saliva or birth products.
    • The spread of Hendra virus between horses is possible wherever horses have close contact with body fluids from an infected horse.
    • All confirmed human cases to date became infected following high level exposures to body fluids of an infected horse, such as doing autopsies on horses without wearing appropriate personal protective equipment, or being extensively sprayed with respiratory secretions.
    • There is no evidence of human to human, bat to human, bat to dog, or dog to human transmission.

    Who is at risk?

    People who have had close contact (particularly high level exposures as described above) with an infected horse, without wearing appropriate personal protective equipment, are at risk.

    How is it prevented?

    Preventing horse infection

    • Protect horse feed from contamination by flying fox fluids.
    • Contact your local veterinarian if you notice unusual disease symptoms, abnormal behaviour or unexpected deaths in your horses. If you cannot contact your veterinarian, contact your animal health authority or the Emergency Animal Disease Watch Hotline on 1800 675 888 (24-hour hotline).
    • Isolate sick horses from other horses.
    • A vaccine for horse is in development and expected to be available soon.

    Preventing human infection

    • While the greatest risk is with sick horses, infected horses can shed Hendra virus for a few days before they show any sign of illness so it is always important to use good hygiene practices when around horses.
    • Don’t kiss horses on the muzzle (especially if the horse is sick).
    • Cover any cuts or abrasions on exposed skin before handling horses and wash your hands well with soap and water, especially after handling your horse’s mouth or nose (e.g. fitting or removing a bridle) and before eating, smoking or touching your eyes, nose or mouth.
    • If body fluids or manure from a horse gets on unprotected skin the area should be washed with soap and water as soon as possible.
    • If a horse becomes unwell and Hendra virus infection may be a possibility, as few people as possible should care for the horse until the infection is ruled out.
    • Appropriate personal protective equipment which prevents contamination of the skin, eyes, nose and mouth by the horse’s body fluids should be worn if close contact with the sick horse is considered essential.
    • Although there is no evidence of Hendra virus spreading from an infected person to another person or animal, health care workers will take a cautious approach and wear personal protective equipment when caring for people suspected or confirmed to be infected.
      If you have been exposed to Hendra virus, you should not donate blood or any other tissue until you are cleared of infection.
      No human vaccine is currently available.

    How is it diagnosed?

    People with suspected Hendra virus infection will usually have blood and urine tests. Depending on their symptoms they may also have nose/throat swabs and/or other tests. People with high level exposures to horse body fluids may have blood samples collected over six weeks to check if they have developed antibodies to the infection.

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    How is it treated?

    There is no specific treatment for Hendra virus infection and cases are treated supportively in hospital or in intensive care. Antiviral medications have not been found to be effective in treating Hendra virus infection. People who have had high exposures to the body fluids of an infected horse may be offered experimental treatment with a type of antibody that may prevent infection.

    What is the public health response?

    • When a horse is diagnosed with Hendra virus infection, the local public health unit will work closely with the state/territory animal health agency, horse and property owners, and veterinarians to identify people who may have been exposed.
    • Public health unit staff will identify people who may be at risk and contact them to assess their exposure.
    • People who may be at risk of infection will be given information about Hendra virus and asked to monitor their health. Where necessary, arrangements will be made for blood tests to be taken.

    Further information

    For further information on Hendra virus in humans:
    Public health unit contact details
    Qld health website: www.health.qld.gov.au/
    NSW health website: www.health.nsw.gov.au/

    For further information on Hendra virus in horses:
    Biosecurity Queensland: www.dpi.qld.gov.au
    NSW Department of Primary Industry: www.dpi.nsw.gov.au


    Appendix 3 – Contacts fact sheet
    Hendra virus – information for people who have been exposed to a horse or human infected with Hendra virus

    Introduction

    This fact sheet is specifically for people who have been exposed to a horse or human infected with Hendra virus. Please read the general Hendra virus fact sheet first.

    Why am I being followed up?

    • You have been identified as someone who has had contact with a horse or human that has been confirmed to have Hendra virus infection.

    What is the risk?

    • Several hundred people have been exposed to Hendra virus infected horses and tested for infection - only a few of these people (seven as of October 2011) have become sick and no one has ever had a ‘silent’ infection without symptoms.
    • The small number of people who have contracted Hendra virus infection all became sick following high level exposures to body fluids of an infected horse, such as doing autopsies on horses without wearing appropriate personal protective equipment, or being extensively sprayed with respiratory secretions.
    • Many people have reported high level exposures to infected horses but have remained well.
    • People are at some risk if they have had exposure to an infected horse’s body fluids and appropriate personal protective equipment, including gloves and a mask, was not worn.
    • People with high level exposures to infected horses are most at risk – no one with a lower level exposure has ever developed Hendra virus infection.
    • Affected horses are thought to be potentially infectious to humans for a few days before they become sick but are most infectious after they become sick.
    • No one has ever developed Hendra virus infection after exposure to an infected human.

    What is the follow up?

    • Public health unit staff identify people who may be at risk and contact them to assess their exposure.
    • People who may be at risk of infection are given information about Hendra virus and asked to monitor their health.
    • Blood tests are not routinely required following most exposures to horses or humans with Hendra virus infection, but arrangements will be made for testing where appropriate.
    • People who have had high exposures to the body fluids of an infected horse may be offered testing and experimental treatment with a type of antibody that may prevent infection.

    What if I get symptoms?

    • Symptoms of Hendra virus infection in humans typically develop between 5 and 21 days after contact with an infectious horse.
    • If you become unwell during this time you should seek medical advice promptly.
    • Fever, cough, sore throat, headache and tiredness are common initial symptoms.
    • Meningitis or encephalitis (inflammation of the brain) can develop.
    • Symptoms of encephalitis include headache, high fever, and drowsiness, and sometimes convulsions and coma.
    • Although there is no evidence of Hendra virus spreading from an infected person to another person, health care workers will take a cautious approach and wear personal protective equipment when caring for people suspected or confirmed to be infected.

    How is it diagnosed?

    • People with symptoms of suspected Hendra virus infection will usually have blood and urine tests. Depending on their symptoms they may also have nose/throat swabs and/or other tests.

    How is it treated?

    • There is no specific treatment for Hendra virus infection and cases are treated supportively in hospital or in intensive care.
    • Antiviral medications have not been found to be effective in treating Hendra virus infection.
    • Antibodies against Hendra virus have been used to treat people with the infection, but this treatment remains experimental.

    Mental health

    This experience may be stressful for you and your family. If you feel worried or concerned it’s a good idea to talk over your concerns with your GP.

    Am I a risk to others?

    • As a precaution you should not donate blood or any other tissue until you are cleared of infection.
    • Whilst you remain well, you are not a risk to other people and you are not restricted from your usual activities.

    Further information


    For further information contact your public health unit or general practitioner.
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    Appendix 4 - Hendra Virus (Confirmed Animal Case) Exposure Assessment From




    Appendix 5 – Public health checklist

    PHU Incident Management Checklist for confirmed equine case of Hendra virus infection, or where state/territory animal health authority advises of heightened suspicion

    Contact relevant state/territory animal health authority to:
    • Clarify timeline for results of laboratory testing, if not already confirmed
    • Ensure appropriate infection control measures are in place
    • Identify potential contacts and establish whether/what communication has occurred
    Contact potential contacts to:
    • Assess horse exposure/s using Exposure assessment form/s
      • If high exposure to body fluids of a confirmed equine case, liaise with an infectious diseases physician as soon as practicable regarding PEP
      • If medium exposure, discuss as soon as practicable with appropriately experienced public health practitioners and infectious diseases physician/s to reach consensus on exposure assessment
    • Assess current health status
      • Refer any symptomatic people to appropriate care
    • Counsel about risk
    • Advise about laboratory testing recommendations
    • Provide Hendra Factsheet for contacts
    • Advise about self monitoring of their health and to seek early medical advice if they develop fever or respiratory or neurological symptoms within 3 weeks of exposure
    • Advise them to access their usual health care practitioner to assess need for ongoing physical and psychological support, medical or workers compensation certification and referral to other services as necessary
    Other issues:
    • Maintain communication with state/territory CDB
    • Establish a team to manage public health response if confirmed equine case
    • Involve state or territory workplace health and safety authority if confirmed transmission has occurred in a workplace


    PHU Case Checklist for suspected or confirmed human case of Hendra virus infection

    Case Name and ID number: ..................................................................................

    For all suspected or confirmed human cases

    Contact the case’s doctor to:
    • Obtain case’s history
    • Confirm results of relevant pathology tests or recommend relevant tests be done
    • Ensure appropriate infection control measures are in place
    If confirmed or heightened suspicion on clinical and epidemiological grounds

    Contact the case’s doctor to:
    • Ensure liaison with an infectious diseases physician occurs
    • Seek contact details for case or carer
    Contact the case or carer to:
    • Confirm onset date and symptoms of the illness
    • Identify any exposures to known equine cases, and other equine exposures where relevant
    • Assess equine exposure/s using Exposure assessment form, where relevant
    • Identify contacts and obtain contact details
    • Provide advice, including on recommended restrictions, and Hendra Factsheet
    Liaise with relevant state/territory animal health authority to:
    • Alert to case
    • Discuss need for testing of relevant horses, where appropriate
    If confirmed human case, contact case’s contacts to:
    • Assess exposure
    • Provide advice and Hendra Factsheet for contacts
    Other issues:
    • Maintain communication with state/territory CDB
    • Establish a team to manage public health response if confirmed human case
    • Involve state or territory workplace health and safety authority if confirmed transmission has occurred in a workplace
    • In states and territories where Hendra virus infection is notifiable, enter case data onto notifiable diseases database