Abstract

• Avian influenza viruses are zoonotic influenza viruses. However, they are different from human influenza viruses and are not readily transmissible from person to person;
• The main route of human infection of avian influenza is direct contact with infected birds or their secretions and excretions, or contact with contaminated environments;
• There is no evidence of human infection of avian influenza from consumption of thoroughly cooked food to date;
• To further ensure food safety, use designated utensils when preparing raw poultry or eggs to avoid cross-contamination of viruses on raw poultry with other food, heat the poultry to a core temperature of 70°C or above, cook eggs thoroughly and maintain good hygiene practices;
• Since the implementation of the “separation between humans and poultry” measure in Macao in May 2017, the spread of avian influenza has been controlled and the recurrence of human infection of avian influenza in Macao has been prevented, thus the health of the public and the stable socio-economic development of Macao have been effectively safeguarded;
• In accordance with the current legislation in Macao, all live and fresh food is required to pass mandatory testing and inspection upon importation into Macao. The Municipal Affairs Bureau (IAM) continuously monitors applications for importation of products of animal origin from all regions and takes corresponding preventive and control measures in accordance with the announcements of the World Organisation for Animal Health (WOAH). 

Introduction

In February 2023, the World Health Organization (WHO) reported two cases of human infection caused by the Avian Influenza Type A (H5N1) virus in Cambodia. As one of the many types of avian influenza viruses, the H5N1 virus is spreading widely among poultry around the world and the number of infections in mammals, including humans, is increasing, making the global spread of H5N1 avian influenza worrying.

About Avian Influenza

Avian influenza is an infectious disease contracted by poultry and caused by the influenza A virus. Depending on the combination of haemagglutinin (H) and neuraminidase (N) proteins in influenza A viruses, avian influenza can be classified into different subtypes, such as H5N1, H5N6 and H7N7 viruses. Depending on the pathogenicity in birds, avian influenza can be classified into highly pathogenic and low pathogenic avian influenza.

Avian influenza viruses are zoonotic influenza viruses, although they are different from human influenza viruses and do not spread easily from person to person. The main route of human infection is through direct contact with infected birds or their secretions and excretions, or contact with contaminated environments. According to the WHO, whenever the avian influenza virus is transmitted among poultry, there is a risk of spread of infection and outbreak of human cases on a small scale if humans come into contact with infected poultry or contaminated environments.

Cases of human infection of avian influenza have been reported in many countries and regions around the world. Symptoms can range from flu-like symptoms (e.g. fever, cough, sore throat, etc.) to severe respiratory infections (e.g. pneumonia). More severe forms of infection (e.g. H5N1, H5N6, H7N9 or H10N8 viruses) can lead to respiratory failure, multiple organ failure and even death.

Avian Influenza and Food Safety

According to the WHO, in the process of preparing poultry for consumption, the slaughtering of live infected poultry poses the highest risk of human infection of avian influenza. There is no evidence that humans can be infected with avian influenza through the consumption of thoroughly cooked food to date. Although all parts of the infected poultry and its eggs (including the white, yolk and surface of the eggshell) may carry the virus, cooking poultry (e.g. chicken, duck, goose, turkey, etc.) and eggs thoroughly is a safety measure to kill the avian influenza virus. In an area where there is no outbreak, there is no risk of human infection through the handling or consumption of poultry.

When preparing raw poultry or eggs, use designated utensils to avoid cross-contamination of viruses on raw poultry with other food, heat the poultry to a core temperature of 70°C or above, cook eggs thoroughly (until the yolks and whites are completely solidified) and maintain good hygiene practices to further ensure food safety.

Regulation in Macao

Since the emergence of avian influenza outbreaks in various regions, the Macao SAR Government has been monitoring the development of avian influenza outbreaks in various regions and Macao and has adopted a series of preventive and control measures. Between February 2016 and February 2017, five cases of avian influenza viruses in live poultry, as well as the first confirmed case of human infection with avian influenza A (H7N9), were detected in Macao. Based on public health considerations and practical epidemic prevention needs, the Macao SAR Government decided to officially implement the “separation between humans and poultry” measure in Macao with effect from 1 May 2017 to stop all trading and selling of live poultry for consumption purposes in Macao. This was done to break the transmission chain of avian influenza between humans and live poultry effectively, so that the possibility of community outbreak of avian influenza can be reduced and the threat of avian influenza to Macao residents can be minimised.

Since the implementation of the “separation between humans and poultry” measure, the spread of avian influenza has been effectively controlled and the recurrence of human infection of avian influenza in Macao has been prevented, effectively safeguarding the health of the public and the stable socio-economic development of Macao.

Under the current legislation in Macao, all live and fresh food must undergo mandatory inspection and quarantined upon importation. At the time of inspection, a valid health certificate issued by the competent authorities of the place of origin must be produced to prove that the product did not originate from an infected area and is appropriate for human consumption. The product must pass the inspection before it can be imported. In the event of an outbreak in a particular region, it is not possible for the local health authorities to issue a health certificate. At the same time, IAM will also continue to monitor applications for importation of products of animal origin from all regions and take preventive and control measures in accordance with the announcements of the World Organisation for Animal Health (WOAH) to ensure that the public can consume the products safely. In addition, the “International News” page of the Food Safety Information website (www.foodsafety.gov.mo) of IAM contains food animal epidemic prevention information from around the world, including information on avian influenza and bovine spongiform encephalopathy (commonly known as “mad cow disease”), etc., for the reference of the food sector in Macao.