Human Health Issues related to Avian Influenza in Canada

Footnotes

[1] Although all birds are thought to be susceptible, not all species are equally susceptible or affected by avian influenza viruses (e.g., pigeons resist infection with avian influenza)

[2] It is expected that these recommendations may also be applicable to outbreaks of influenza in pigs that result in human illness, with consideration given to the unique aspects of such an outbreak at the time.

[3] If efficient human to human transmission occurs and the outbreak is not contained through the use of the recommended control measures, then all jurisdictions should use the measures outlined in the Canadian Pandemic Influenza Plan to respond to the potential pandemic threat.

[4] This finding highlights the importance of basing the risk assessment on the specific virus subtype/strain as recommended in section 7.2.1.

'[5] Recently a single case of H7N2 infection was retrospectively identified in an individual who had recovered from a respiratory illness (including chest x-ray changes) that occurred in the United States in November 2003. This case was reported to the WHO on April 19, 2004 after it was laboratory confirmed by the CDC, Atlanta.

[6] See the Canadian Pandemic Influenza Plan for more details on the WHO and Canadian Pandemic Phases.

[7] Each employer is responsible for the occupational health and safety of their own employees. However CFIA could provide PPE to non-CFIA employed individuals who visit CFIA designated work sites. Occupational health personnel may be involved in case detection / surveillance activities however the case and contact follow-up and management would be the responsibility of local public health.

[8] Note; the provincial veterinary service in most P/Ts operates a veterinary diagnostic laboratory that is used by veterinary practitioners, and may play a significant role in an outbreak (as was the case in the British Columbia 2004 outbreak of H7N3), both in testing of specimens and liaising with local producers.

[9] With the exception of this source (i.e. an infected human), all other sources are considered "avian/animal sources".

[10] The "site" would be defined at the time by the authority involved in the animal side of the response. It would depend on the specific situation but the affected site would not involve entire flight paths of wild birds.

[11] An H3 and H6 were also reported with no N information available.

[12] This notification should occur directly between P/Ts to avoid delays and should include (as permitted by P/T legislation) the individual's name and contact information as well as the status of the individual with respect to their clinical illness and any required ongoing treatment and monitoring.

[13] Similarly if contacts are being actively managed (e.g. daily active surveillance) as part of the outbreak response, these individuals should also be notified to their respective jurisdiction if the monitoring period has not been completed by the time the individual is leaving the outbreak jurisdiction.

[14] During the outbreak of H7N7 in the Netherlands in 2003, only 6% of farmers reported consistent use of facial masks and 1% reported consistent use of goggles while working with infected poultry. In cullers, compliance was only slightly better; 25% consistently used facial masks and 13% used goggles. (17)

[15] Contacting of individuals exposed to an avian source of virus, may be indirect through staff supervisors or occupational health authorities. The necessity of individual contact should be determined by the local public health authority depending on the epidemiology of the outbreak and efficient human resource allocation.

[16] List of possible sources can be found in the Terminology section of this document (section 4.2)

[17] With the exception of visiting a health care provider, individuals recommended to be on self-isolation should stay home for 24 hours after symptom resolution and avoid close contact with unexposed household members, unless an alternative diagnosis is established.

[18] Frequency of active surveillance should be determined by the public health authority with consideration given to reasonable resource allocation and severity of the illness (especially if the outbreak is large).

[19] Hand hygiene is the most important measure in preventing the spread of infection after contact with infected or potentially infected birds, contact with contaminated surfaces, or after removing gloves. Workers or other persons are at risk of exposure should be educated on the importance of strict adherence to and proper use of hand hygiene.

[20] Fit testing and training is necessary prior to use of a N-95 or better respirator. This type of respirator is being recommended for these individuals since the process of culling or environmental decontamination (e.g. in affected barns) may cause contaminated materials (e.g. sawdust soiled with manure) to be suspended in the air, creating a risk potentially akin to an aerosol generating procedure in a hospital setting.

[21] It is expected that similar recommendations would be made if the source of the outbreak was in pigs/swine as opposed to in poultry/avian, however this would need to be re-visited based on the epidemiology of the outbreak.

[22] Since oseltamivir is only approved for post-exposure prophylaxis, "seasonal" or "pre-exposure" use would be considered an off-label use.

[23] As per the Canadian Pandemic Influenza Plan the recommended usage may be more broad for Pandemic Phases 4 and 5 where prophylaxis of household contacts may be implemented as part of containment activities.

[24] This recommendation is meant to apply specifically to the avian influenza situation where relatively small numbers of human cases are expected and there is evidence of prolonged viral replication suggesting that the use of antivirals is therefore potentially beneficial.

[25] Dose adjustment may be necessary with renal impairment

[26] For a maximum duration of 6 weeks

[27] RISC includes F/P/T epidemiologists and representatives from the National Microbiology Laboratory and the Canadian Public Health Laboratory Network.

[28] During the H7 outbreak in the Netherlands in 2003, it was found that conjunctival swabs, even from individuals with no eye-related symptoms, had a superior yield of H7 viruses and therefore were an important specimen to collect for virus isolation.

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