No human infection reported in Korea

The spread of H5N8 avian influenza (AI) that broke out in mid-January has not been eradicated yet, causing enormous damages to farmers and related industries. The consumption of chicken and duck meat has been decreasing, while the cost for AI quarantine activities has been increasing. Problems are not limited to economic damages as concerns over human infection are rising among the Korean people.

Human infection occurs with complicated conditions that involve numerous factors such as the experience of virus infection, protective immunity of human body, preventative measures for infection and disease control. In other words, it cannot be concluded based on some simple factors. Rather, it requires a comprehensive judgment. When taking all these factors into account, the chance for human infection with H5N8 is very slim at this point.

Avian influenza has occurred in Korean chicken and ducks five times since 2003. Unlike the previous four involved with the strain of H5N1, the influenza of this year is the strain of H5N8. H5N1 infected about 650 people in 15 countries including Southeast Asian countries, China and Egypt over the past 10 years. This is why the strain was considered a candidate for “pandemic” that is likely to spread rapidly and cause critical damages.

During a pandemic, the disease is spread by people-to-people infection. However, there has been no such signal for H5N8 as of now. Even during the outbreak of H5N1 AI, no human infection was reported in Korea. Only a few “infected people without symptoms” were found. According to the World Health Organization, people are categorized as patients only when they have been exposed to virus, have acute respiratory symptoms and are tested positive. Infected people who develop no symptoms are not considered patients.

Then, why does human infection with H5N1 occur often in Southeast Asia and China? It is because the source of infection such as chicken and ducks are raised in an environment different from that of Korea. Farmers in Southeast Asia and China still raise chicken and ducks in an open yard around their houses as Korea did in the 1960s and 1970s. This kind of practice raises the chances of people being exposed to animal feces or other discharges. The case in point of H7N9 has infected over 300 people so far since its outbreak in China in 2013. Consumers were infected with the virus in the process of cooking chicken or ducks that they bought alive in a traditional market.

In Korea, poultry are raised in a segregated farm and meat is processed sanitarily. Thus people are not directly exposed to the risk of infection. To prevent the spread of AI, people participating in slaughtering wear quarantine clothes and take anti-viral medicine for just in case. They also take other preventive measures such as vaccination.

Korea is globally recognized as an AI-free nation that has successfully eradicated the spread of AI. It cannot be compared to countries in Southeast Asia where AI has become an endemic.

Lastly, H5N8 strain was found in Chinese ducks but not in human bodies. The Korea Centers for Disease Control and Prevention analyzed the H5N8 virus but did not find any genetic mutation related to human infection or resistance to antiviral agents. So the bottom line is that there is little chance for human infection with H5N8 AI. What we should do now is to make all-out efforts in putting the epidemic under control and eliminating it while stimulating the consumption of chicken and duck meat to help farmers in trouble.

Korea is positioned in the route of migratory birds that move from Siberia in winter. Besides, many of its poultry farms are located in the southwest part of the nation, which is geographically close to China where AI has become an endemic. This means Korea is at high risk of AI epidemic. The Korean government should find fundamental measures to prevent the occurrence of AI to make this year`s H5N8 strain of bird flu become the last AI in Korea. Supports from experts will also be necessary.