The Fraser Valley in British Columbia is currently experiencing resurgence of Highly Pathogenic Avian Influenza (HPAI) among birds.
The most affected sites are commercial poultry farms in areas around Abbotsford and Chilliwack. However, all commercial poultry farms, and all backyard bird flocks are susceptible to this virus.
What is the human health risk?
- Highly Pathogenic Avian Influenza (HPAI) is a type of Influenza A. It causes bird flu but can also spread to humans. The currently circulating strain in North America is H5N1.
- Increased HPAI activity among birds and mammals increases the potential for human exposure.
- There have been increased detections of avian influenza spillover to several mammalian species in B.C. and throughout the Americas. In several large marine mammal outbreaks animal-to-animal transmission has not been ruled out.
- Increased number of detections of the current H5N1 strain among mammals raises concerns that the virus might adapt to infect humans more easily.
- Concurrent infection with human and avian influenza in a human host could provide an opportunity for genetic re-assortment. This could facilitate human adaptation and associated pandemic risk.
Who is at increased risk for HPAI?
- Commercial Poultry Farm workers: Individuals with insufficient Personal Protective Equipment (PPE) and very close exposure to a flock or group of sick or dead animals infected with HPAI, or to birds that have been directly implicated in human cases (e.g., farm family member or worker who handled sick animals)
- People involved in handling sick animals or exposed to affected environments (including animal disposal) as part of outbreak control efforts (e.g., cullers), and where consistent use of PPE cannot be assured.
- Household/family contacts of or unprotected face to face interaction with a suspected or confirmed human HPAI patient during the expected period of communicability.
What are signs and symptoms of human HPAI infection?
Symptoms may range from no symptoms or mild illness to severe Influenza-like illness and can be non-specific. Common signs and symptoms include:
- Fever or feverishness, malaise, fatigue, myalgia, arthralgia.
- Cough, rhinorrhea, headache, sore throat.
- Conjunctivitis symptoms including redness to sclera, eyelid/conjunctival inflammation, excessive tearing, pruritus, eye pain/burning, discharge, photosensitivity.
- Gastrointestinal symptoms including abdominal pain, nausea, diarrhea, vomiting.
- Respiratory complications including shortness of breath, chest pain, pneumonia, respiratory failure and death.
How to test for HPAI?
Clinicians should have a low threshold for HPAI virus testing of individuals with clinically compatible symptoms (see above) who report sick bird or other exposures of concern within the ten days prior to onset.
- Nasopharyngeal and throat swab should be collected as close to the onset of illness as possible. When testing is indicated it should be done preferably within five days of symptom onset.
- However, clinicians should have a low threshold for testing beyond this period as detection can occur up to three weeks, particularly in children and the immunocompromised individuals.
- Please send all specimen for testing directly to the BCCDC Public Health Laboratory (PHL).
- The BCCDC PHL eLab Handbook provides testing information, including: ordering procedures, process information, specimen collection instructions, and handling and transport instructions.
- Lab requisitions should specify exposure to avian influenza virus with wording such as “High-risk for AIV”. The BCCDC Medical Microbiologist on-call should be notified of the case and testing request at 604-661-7033.
What constitutes an exposure to HPAI?
- Close exposure (within two meters) to birds, animals or humans with confirmed HPAI virus infection.
- Exposures include, but are not limited to, being in the same close airspace, touching or handling infected animals; consuming under - or uncooked poultry or egg products from an affected farm; direct contact with contaminated surfaces; being exposed to manure or litter containing high concentration of virus or being in a contaminated air space or environment; visiting a live poultry market with confirmed bird infections or associated with a case of human infection.
What PPE is required in health care setting for HPAI?
During assessment, testing and care or procedures, clinicians should implement appropriate protective measures. For novel influenza viruses, these include airborne, droplet and contact precautions unless otherwise advised. Refer to the PICNET guidance.
What does Fraser Health Public Health do?
- Fraser Health Communicable Diseases teams follows up with commercial operations that the Canadian Food Inspections Agency (CFIA) identifies as affected by HPAI. We also follow individuals who have backyard flocks or are otherwise identified as exposed to infected birds or wildlife.
- The protocols and processes have been in place for several years. They have been iteratively refined and improved with changing virus, testing, and biosecurity practices.
- Fraser Health Communicable Diseases team contacts commercial poultry farms and obtains information about individuals working at the affected locations.
- All the individuals identified by the poultry farm owners as working on the farm are contacted, their personal risks assessed and post-exposure prophylaxis offered when indicated.
How to reduce the risk of HPAI for humans?
- Influenza vaccine: Getting the seasonal influenza vaccine reduces the risk of coinfections and genetic re-assortment. It is strongly recommended for people working with live poultry.
- Treatment: If avian influenza infection is suspected, antiviral treatment with Oseltamivir should be provided without delay. Waiting for lab confirmation is not recommended.
- Post-exposure Prophylaxis: Fraser Health Communicable Diseases team and the Medical Health Officers are available for consultation to clinicians for individuals you may be considering for post-exposure prophylaxis for Avian Influenza.
- Biosecurity: Poultry farmers and workers should follow strict Biosecurity Standards when working with live poultry. This i) minimizes exposures to potentially infected animals, ii) mitigates the risk of acquiring infection, and iii) helps monitor to ensure timely identification of human cases.