Avian influenza: What nurses need to know

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What is avian influenza?

Avian influenza, also known as bird flu, is caused by influenza Type A viruses that occur naturally among different bird species. Like human influenza viruses, avian influenza contains two glycoprotein surface antigens, hemagglutinin (H) and neuraminidase (N), responsible for viral entry and dissemination into host cells. Based on disease severity in infected birds, they are either classified as low pathogenic (LPAI) or highly pathogenic avian influenza (HPAI).

Since 2020, a highly pathogenic strain of avian influenza – HPAI A(H5N1) clade 2.3.4.4b – has spread globally, causing unprecedented outbreaks in wild birds, poultry, farmed minks, seals and other mammals. The virus has also been detected in domestic animals such as dogs and cats in several countries. As of March 2024, HPAI A(H5N1) clade 2.3.4.4b virus has spread in dairy cattle across several U.S. states. Non-viable viral particles have also been detected in pasteurized milk samples. Recently, avian influenza A(H5N1) was detected in swine for the first time in the U.S.

How is avian influenza transmitted? 

Avian influenza can be transmitted to other animals and people through close contact with an infected animal or fomites and through infectious aerosols. While avian influenza viruses typically do not infect humans, human cases of HPAI A(H5N1) have occurred, especially with unprotected exposures to infected animals. Human illness may range from asymptomatic or mild infections (e.g., subconjunctival hemorrhage) to severe disease and death. Over the past two decades, approximately 904 human H5N1 infections have been reported globally, 464 of which were fatal (case fatality rate of 51 percent). 

The first documented cow-to-human transmission occurred in a dairy worker, occupationally infected via contaminated hands and/or through infectious aerosols from infected cows or activities in the dairy farm environment. The dairy worker reported wearing gloves when working with cows but did not use any respiratory or eye protection.

What is the risk of sustained human-to-human transmission of avian influenza?

The wide geographic spread of HPAI A(H5N1) virus in birds and mammals increases opportunities for human exposure, which increases the risk of transmission. Farmworkers are at high risk of occupational exposure to avian influenza. However, the number of avian influenza infections among farmworkers is unknown. Poultry and dairy industries largely rely on undocumented immigrants who often face precarious, dangerous working conditions and substandard housing conditions. As a result, workers may be reluctant to seek care and face barriers to accessing health care.

Additionally, the longer the virus persists in animal population, the more mammal species it infects, and the more workers who are exposed, the higher the chances of acquiring mutations that could facilitate efficient human-to-human transmission. 

Investment in preparedness, active surveillance and response, data sharing, vaccine preparedness and personal protective equipment (PPE) stockpiles is urgently needed to control the spread of the highly pathogenic avian influenza A(H5N1) in animals. Nurses know that preparedness is paramount to pandemic response. The United States’ public health response must be rooted in the precautionary principle – to prevent zoonotic spillovers from happening in the first place. Management and control of the HPAI A(H5N1) outbreak also requires a One Health approach – an approach that considers and protects human health, environmental health, and animal health at the same time.

What protections do nurses and other health care workers need when caring for a patient with suspected or confirmed avian influenza?

Health care employers are responsible for providing a safe work and patient care environment. Multilayered infection prevention measures should be implemented in all health care facilities:

  • Patient screening – Screen patients for influenza-like illness who may have been exposed to infected animals.
  • Isolation and source control – Patients with suspected or confirmed avian influenza should be isolated promptly in an airborne infection isolation room (AIIR).
  • Ventilation – Adequate ventilation is also essential for reducing the risk of influenza transmission in lobbies, waiting rooms, and other areas of the facility where a suspected or confirmed case could be present before being identified and isolated.
  • Personal protective equipment – Health care workers caring for patients with suspected or confirmed avian influenza infections should wear a powered air-purifying respirator (PAPR), coveralls impervious to viral penetration with head and shoe coverings and gloves.
  • Exposure notification and contact tracing – Employers should conduct contact tracing and immediately notify staff who were potentially exposed. Exposure should include both direct contact while providing care and sharing air space (e.g., being in the same waiting room, triage station, etc.).
  • Paid precautionary medical removal – Employers should provide paid precautionary medical removal for any health care worker who is removed from the workplace due to occupational exposure or infection with avian influenza.

NNU is leading the campaign to win a national enforceable OSHA infectious diseases standard rooted in the precautionary principle to protect health care workers from aerosol-transmissible diseases like avian influenza.

 

Video: Three things nurses need to know about avian influenza 

See our full series of H5N1 Avian Flu Educational Videos with Rocelyn De Leon-Minch, RN

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