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Summary of Assessment of Public Health Risk to Canada Associated with H7N9 Avian Influenza Human Infections in China
Current as of April 10, 2013
Risk Assessment
Sequencing of the A(H7N9) virus by the World Health Organization (WHO) Chinese National Influenza Centre in Beijing revealed HA and NA genes from A(H7N9) and remaining genes from A(H9N2), identifying this virus as a novel reassortant virus (2, 3). The novel A(H7N9) virus does not appear to cause severe illness in birds, and is different from previously identified A(H7N9) viruses in birds although all genes clearly are related to genes from recent Eurasian influenza A viruses from wild birds and poultry. Presently, this influenza A(H7N9) virus is considered a Foreign Animal Disease (FAD) agent as there may be consequences if this pathogen were to circulate in avian populations in Canada.
Recommendations for Canada
Surveillance
Health care professionals are encouraged to maintain vigilance for cases of avian influenza infection, and notify the appropriate Public Health Departments in your jurisdiction of any suspected cases. Provinces and Territories are asked to continue to report cases of severe respiratory illness to the Agency using the Emerging Respiratory Pathogens and Severe Respiratory Illness Case Report Form, and note any travel history to China within 10 days of illness onset. Cases are to be reported through Canada?s National Surveillance System ? FluWatch.
Travel Advisory
A travel health advisory is posted on the Agency?s website. It does not recommend any restrictions on travel but encourages travellers to take routine precautions.
Infection Control
Recommendations for infection prevention and control measures for patients presenting with suspected or confirmed infection or co-infection with the H7N9 in acute care settings:
<TABLE class=alignBoxCenter border=1 summary="Summary of Assessment of Public Health Risk to Canada Associated with H7N9 Avian Influenza Human Infections in China" cellPadding=5><THEAD><TR><TH>Type of Precautions</TH><TH>Infection Prevention and Control Measures</TH></TR><CAPTION>Infection Prevention and Control Measures</CAPTION><TBODY><TR><TD>Routine Practices</TD><TD>For all patients, at all times, in all health care settings.</TD></TR><TR><TD>Contact and Droplet Precautions</TD><TD>Includes gloves and a gown upon entering the patient?s room.
A mask and face/eye protection should be worn when the health care workers will be entering the patients room, or working within two metres of the patient.
</TD></TR><TR><TD>Airborne Precautions</TD><TD>For performing aerosol-generating medical procedures (Medical procedures that can generate aerosols as a result of artificial manipulation of a person?s airway. Procedures include: intubation and related procedures (e.g. manual ventilation, open endotracheal suctioning), cardiopulmonary resuscitation, sputum induction, nebulized therapy, surgery, autopsy, and noninvasive positive pressure ventilation (CPAP, BiPap).)
Ensure that aerosol-generating medical procedures (AGMPs) are carried out using a process and in an environment that minimizes the exposure risk for healthcare workers, ensuring that non-infected patients, visitors and others in the healthcare settings are not unnecessarily exposed to H7N9.
The number of personnel in the room should be limited to those required to perform the aerosol-generating medical procedure.
Aerosol-generating medical procedures should be performed in airborne infection isolation rooms whenever feasible.
</TD></TR></TBODY></TABLE>
The importance of use of goggles/eye protection cannot be over-emphasized for this virus. Historically H7 influenza A viruses have shown a marked ocular tropism and have been associated with conjunctivitis in humans, with occasional cases leading to more severe illness.
Refer to the Agency Guideline Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings (2013, in press) for more information.
This guidance will be updated as new evidence becomes available.
Biosafety
Based on the clinical presentation of severe respiratory illness and death in humans, the potential for this virus to be a pandemic agent, and that the virus is currently considered a foreign animal disease agent, this influenza A(H7N9) virus is classified as a Risk Group 3 human and animal pathogen requiring Containment Level 3 for all proliferative in vitro or in vivo activities. Non-proliferative diagnostic/clinical activities can be conducted at Containment Level 2 with additional requirements, as specified below. In the event of a non-negative human sample, it is strongly recommended that the work with the sample be stopped and the sample be transferred to the National Microbiology Laboratory (NML). In the event that a veterinary diagnostic laboratory detects a non-negative sample, the work is to be stopped and the sample be transferred to the National Centre for Foreign Animal Disease (NCFAD) as per the policy in the Foreign Animal Disease Diagnostic Laboratory Containment Standard. The biosafety advisory can be found on the PHAC website.
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Date Modified: 2013-04-10
Current as of April 10, 2013
Risk Assessment
- The public health risk posed by H7N9 from China to Canada is considered low at this time. The cases reported to date have been limited to a particular geographic area within China, and there has been no confirmed human to human transmission of H7N9. Updated risk assessments will be made available based on any new evidence.
- H7 viruses have not to date shown evidence of sustained human-to-human transmission, and have not evolved into pandemic strains.
- On March 31, 2013 health authorities in China notified the World Health Organization (WHO) that avian influenza A (H7N9) virus infection was causing severe respiratory illness in humans. This is the first time this virus has been identified as causing illness in humans.
- As of April 10, 2013, WHO is reporting 28 confirmed human cases, including 9 deaths, 14 severe cases, and 5 mild cases in Shanghai, Anhui, Jiangsu and Zhejiang provinces. The median age of cases is 61.5 years; ages range from 4 to 87 years. There are no epidemiologic links among the cases. More than 600 close contacts of confirmed cases are being closely monitored, with no evidence of human to human transmission identified.
- The source, reservoir, communicability, and incubation period of the H7N9 is currently unknown; this virus has been found in chickens, pigeons and quails in China. Canada does not import poultry from China.
- The WHO is working closely with the national authorities to better understand the situation and will communicate important updates as it becomes available. The Agency will provide any updated documentation or guidance from the WHO as they become available.
- No vaccine is currently available for this subtype of the influenza virus, although preparatory work is underway should this become necessary.
- The H7N9 virus, based on preliminary test results provided by the WHO Collaborating Centre in China, suggest that the virus is susceptible to the neuraminidase inhibitors (oseltamivir and zanamivir), both of which are held in the National Antiviral Stockpile and National Emergency Stockpile System.
- The Agency's National Microbiology Laboratory (NML) has access to the H7N9 whole genome sequence which provides the NML with the capability to rapidly detect the H7N9 virus. NML has refined diagnostic assays and has supported provincial laboratories with the ability to test for this virus.
Sequencing of the A(H7N9) virus by the World Health Organization (WHO) Chinese National Influenza Centre in Beijing revealed HA and NA genes from A(H7N9) and remaining genes from A(H9N2), identifying this virus as a novel reassortant virus (2, 3). The novel A(H7N9) virus does not appear to cause severe illness in birds, and is different from previously identified A(H7N9) viruses in birds although all genes clearly are related to genes from recent Eurasian influenza A viruses from wild birds and poultry. Presently, this influenza A(H7N9) virus is considered a Foreign Animal Disease (FAD) agent as there may be consequences if this pathogen were to circulate in avian populations in Canada.
Recommendations for Canada
Surveillance
Health care professionals are encouraged to maintain vigilance for cases of avian influenza infection, and notify the appropriate Public Health Departments in your jurisdiction of any suspected cases. Provinces and Territories are asked to continue to report cases of severe respiratory illness to the Agency using the Emerging Respiratory Pathogens and Severe Respiratory Illness Case Report Form, and note any travel history to China within 10 days of illness onset. Cases are to be reported through Canada?s National Surveillance System ? FluWatch.
Travel Advisory
A travel health advisory is posted on the Agency?s website. It does not recommend any restrictions on travel but encourages travellers to take routine precautions.
Infection Control
Recommendations for infection prevention and control measures for patients presenting with suspected or confirmed infection or co-infection with the H7N9 in acute care settings:
<TABLE class=alignBoxCenter border=1 summary="Summary of Assessment of Public Health Risk to Canada Associated with H7N9 Avian Influenza Human Infections in China" cellPadding=5><THEAD><TR><TH>Type of Precautions</TH><TH>Infection Prevention and Control Measures</TH></TR><CAPTION>Infection Prevention and Control Measures</CAPTION><TBODY><TR><TD>Routine Practices</TD><TD>For all patients, at all times, in all health care settings.</TD></TR><TR><TD>Contact and Droplet Precautions</TD><TD>Includes gloves and a gown upon entering the patient?s room.
A mask and face/eye protection should be worn when the health care workers will be entering the patients room, or working within two metres of the patient.
</TD></TR><TR><TD>Airborne Precautions</TD><TD>For performing aerosol-generating medical procedures (Medical procedures that can generate aerosols as a result of artificial manipulation of a person?s airway. Procedures include: intubation and related procedures (e.g. manual ventilation, open endotracheal suctioning), cardiopulmonary resuscitation, sputum induction, nebulized therapy, surgery, autopsy, and noninvasive positive pressure ventilation (CPAP, BiPap).)
Ensure that aerosol-generating medical procedures (AGMPs) are carried out using a process and in an environment that minimizes the exposure risk for healthcare workers, ensuring that non-infected patients, visitors and others in the healthcare settings are not unnecessarily exposed to H7N9.
The number of personnel in the room should be limited to those required to perform the aerosol-generating medical procedure.
Aerosol-generating medical procedures should be performed in airborne infection isolation rooms whenever feasible.
</TD></TR></TBODY></TABLE>
The importance of use of goggles/eye protection cannot be over-emphasized for this virus. Historically H7 influenza A viruses have shown a marked ocular tropism and have been associated with conjunctivitis in humans, with occasional cases leading to more severe illness.
Refer to the Agency Guideline Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings (2013, in press) for more information.
This guidance will be updated as new evidence becomes available.
Biosafety
Based on the clinical presentation of severe respiratory illness and death in humans, the potential for this virus to be a pandemic agent, and that the virus is currently considered a foreign animal disease agent, this influenza A(H7N9) virus is classified as a Risk Group 3 human and animal pathogen requiring Containment Level 3 for all proliferative in vitro or in vivo activities. Non-proliferative diagnostic/clinical activities can be conducted at Containment Level 2 with additional requirements, as specified below. In the event of a non-negative human sample, it is strongly recommended that the work with the sample be stopped and the sample be transferred to the National Microbiology Laboratory (NML). In the event that a veterinary diagnostic laboratory detects a non-negative sample, the work is to be stopped and the sample be transferred to the National Centre for Foreign Animal Disease (NCFAD) as per the policy in the Foreign Animal Disease Diagnostic Laboratory Containment Standard. The biosafety advisory can be found on the PHAC website.
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Date Modified: 2013-04-10
