Most avian influenza viruses do not cause disease in humans. However, some (including H5N1 and H7N9) can infect humans and cause disease. Outbreaks of these avian influenza viruses have heightened international health agencies’ concern about the likelihood of an influenza pandemic occurring.
On this page:
- Avian Influenza A(H7N9) in China
- About Avian influenza
- New Zealand’s preparation for a pandemic
- Case definitions
The Ministry is monitoring the international situation regarding Avian Influenza A(H7N9) and will be keeping the health sector and the public updated should it change.
In March 2013, health authorities in China notified the World Health Organization (WHO) of cases of human infection with avian influenza A(H7N9). The WHO is working closely with Chinese authorities in their intensive surveillance and response to a number of cases where humans have contracted Avian Influenza A(H7N9).
As of 24 October 2013, the WHO advise that:
- the risk of international spread is low
- there were 137 cases, including 45 deaths, reported in China
- there is no evidence of sustained human-to-human transmission
- WHO advises against limiting travel or trade with China.
Read the latest update from the WHO
The Ministry of Health has been updating its advice to the health sector and will continue to do so as the situation changes.
- As of 1 August 2013 Influenza A(H7N9) is notifiable as ‘non-seasonal influenza’ (Schedule 1 of the Health Act 1956).
- Interim clinical and diagnostic guidance has been sent to DHB clinicians and laboratories, and to Medical Officers of Health. This includes advice around possible symptoms from H7N9. (see case definitions below and guidance document attached)
- ESR’s National Influenza Centre in Wellington is able to test for H7N9 – although no cases have been identified
- New Zealand has a pandemic plan which could be activated at short notice, if it was needed. It is a whole-of-government plan with the Ministry of Health as the coordinating agency
- The Ministry of Health maintains a strategic national reserve of critical clinical items that need to be on hand immediately in case of a pandemic in order to reduce the potential impact of pandemic influenza on New Zealanders.
Advice for travellers - on the Safe Travel website.
Avian influenza, or ‘bird flu’ is a contagious disease caused by viruses that normally infect only birds. It has occasionally infected humans who have had close contact with poultry or wild birds. There is currently no evidence of sustainable transmission of avian influenza from person to person.
The most well known example is the avian influenza subtype A(H5N1) virus currently circulating in poultry in parts of Asia and northeast Africa. Small numbers of people have become infected with this virus causing serious illness and/or death. These people contracted the virus after having close contact with infected birds. There is concern that the current A(H5N1) strain of avian influenza may mutate and cause an influenza pandemic.
Another avian influenza virus, A(H7N9) has recently been diagnosed in eastern China, causing sporadic cases of severe respiratory illness in humans. The source of the infection in these people has not yet been confirmed. There is no evidence that the virus is able to spread readily from person to person.
The WHO has a six-phase alert system to respond to pandemics. The current WHO phase for avian flu is Phase Three (Pandemic Alert: no human to human transmission).
At this stage, the WHO is not recommending against travel to any countries affected by avian influenza. See the World Animal Health Information Database for updates.
The risk of contracting avian influenza is believed to be very low, provided you:
- avoid live animal markets, poultry farms and other places where you may come into close contact with domestic, caged or wild birds
- avoid contact with surfaces contaminated with animal faeces or fluids
- avoid eating or handling undercooked or raw poultry, egg or duck dishes
- avoid dishes made with fresh duck blood; and
- wash your hands regularly.
Normal cooking destroys the avian influenza virus. No cases of avian influenza have been linked to the consumption of properly cooked poultry and egg products.
Why health authorities are concerned
The WHO is worried that an avian influenza virus might change and develop the ability to easily spread from person to person.
A new influenza virus that can easily spread from person to person could spread rapidly around the world, infecting many people and resulting in an influenza pandemic.
An influenza pandemic could cause many deaths and could occur at any time. It would not necessarily be a winter illness.
New Zealand has been planning for this for some time. The Ministry of Health is working with the health sector and other Government agencies to ensure New Zealand is as prepared as possible for a potential pandemic.
The Ministry of Health has a national pandemic plan, New Zealand Influenza Pandemic Plan: A framework for action (2010), and district health boards have local plans.
Application of these case definitions
- These case definitions apply to the current phase of pandemic alert (phase 3).
- Probable and confirmed cases will be notified to WHO.
- The case definitions are intended to standardise reporting. They do not provide complete descriptions of clinical disease.
- The clinical spectrum of Avian Influenza A H5N1and H7N9 disease is broad. Clinicians should exercise their judgment for the treatment, care and triage of persons who may have H5N1 or H7N9 infection.
- For additional information on laboratory testing refer to the National Laboratory Guidelines for Pandemic Influenza: Collection and handling of human specimens for laboratory diagnosis of influenza with pandemic potential.
Influenza A (H5N1) Case definition
Rapid onset of respiratory and generalised signs and symptoms of influenza, which can include fever, chills, sweating, a cough and a sore throat.
Laboratory tests for diagnosis
Laboratory confirmation requires identification of H5N1 virus by at least one of the following:
- real-time reverse transcriptase polymerase chain reaction (RT-PCR)
- viral culture
- four-fold rise in H5N1 virus-specific neutralising antibodies.
- Under investigation: A person who has been referred to the public health service for investigation of possible highly pathogenic avian influenza (HPAI) infection.
- Suspected: A clinically compatible illness in a person who, in the 7 days before the onset of symptoms, did one or more of the following:
– was in an area where HPAI infections (in animals or humans) have been suspected or confirmed in the last month
– consumed raw or undercooked meat from known source animals in an area where HPAI infections have been suspected or confirmed in the last month
– had close contact with suspected or confirmed HPAI-infected animals
– was working in a laboratory that is handling samples from people or animals that are suspected of HPAI infection.
- Probable: A clinically compatible illness with a strong epidemiological link to a confirmed case or defined cluster.
- Confirmed: A person with laboratory-confirmed HPAI infection.
- Not a case: A case that has been investigated and subsequently found not to meet the case definition.
Influenza A(H7N9) case definition
- Suspect case (under investigation): A person with a Severe Acute Respiratory Infection (SARI)1 AND with one or more of the following exposures during the two weeks prior to the onset of symptoms:
– Travel to a country2 where human cases of H7N9 influenza have recently been reported, especially if there was recent direct or close contact with animals (e.g. wild birds, poultry or pigs).
– Close contact3 with a laboratory-confirmed case.
- Probable case: A person fitting the definition of a suspect case but with no possibility of laboratory confirmation for H7N9 influenza, either because the patient or samples are not available for testing AND not already explained by any other infection or aetiology, including all clinically indicated tests for community acquired pneumonia according to local management guidelines.
- Confirmed case: A person with laboratory confirmation of infection with H7N9 influenza by the Institute of Environmental Science and Research (WHO National Influenza Centre).
- An acute respiratory illness with a history of fever or measured fever of ≥38°C, AND cough, AND onset within the past two weeks, AND requiring inpatient hospitalisation (defined as a patient who is admitted under a medical team and to a hospital ward or assessment unit).
- Currently, China (excluding Hong Kong) is the only country that has recently reported human cases of H7N9 influenza.
- Close contacts include:
- Any person who provided care for the patient or who had other similarly close physical contact in the two weeks before symptom onset; this includes health care workers or family members.
- Any person who stayed in the same place (eg, household, office) as a probable or confirmed case while the case was symptomatic.
Note: Although most of the cases to date have presented with a severe acute respiratory illness, mild cases have been reported. If doctors are concerned about patients presenting with milder illness, they should discuss this with the local Medical Officer of Health.
For further information on Influenza A(H7N9) please see the attached document H7N9 Influenza: Important interim information for Medical Officers of Health, Clinicians and Laboratories (27 July 2013) (doc, 80.5 KB)