Avian influenza remains a challenge to China in the post-SARS era

To the Editor:

At the beginning of the 21st century, China has faced a set of challenges in controlling newly emerging infectious diseases that are transmitted from animals to humans, such as severe acute respiratory syndrome (SARS) and avian influenza. The novel avian influenza A (H7N9) virus has caused global concern as a potential pandemic threat. It seems that H7N9 avian influenza is the next chapter in a story that began with the SARS epidemic in China.

As wealth has increased in China, the number of animals raised for food, particularly poultry and pigs, has been expanding rapidly. It is estimated that China has a poultry population of 14 billion, 70% to 80% of which is reared in backyards.¹ Densely populated southern China with backyard poultry farming practices has been a breeding ground for new influenza viruses.² At typical wet markets in China, poultry confined in stacked metal cages could facilitate the transmission of avian influenza viruses. Furthermore, open-air butchering could expose the workers and consumers to avian influenza viruses more easily. However, China is immature in implementing animal disease detection and monitoring. Moreover, obstacles to the timely reporting of animal disease outbreaks still exist.² It is true that individual farmers have few incentives to report sick or dead poultry. The fragmented nature of the agricultural sector makes regulation implementation difficult, as a number of food safety scandals have demonstrated in the last years.³

There is no denying the fact that avian influenza remains a challenge to China during the post-SARS period. Even though China has learned a lot in the last 10 years, it is far from enough. The surveillance and reporting system for avian influenza in poultry has yet to be further improved.