A black-backed gull infected with a highly pathogenic virus was found to be the cause
Experts Emphasize Bird Behavior Study
“In order to prepare for the spread of the virus, we must invest in related research”
Avian influenza (AI) is spreading in the United States. According to the World Health Organization (WHO), it is estimated that 383,000 wild birds from 100 species died from AI between October last year and June this year. Analysts suggest that the number will increase if poultry such as chickens and ducks are included. As there are concerns regarding human and mammalian infections, there are growing calls for the need to closely monitor AI.
○ Rapid spread of highly pathogenic AI
According to the AI monitoring system of the US Department of Agriculture (USDA) on the 23rd, in the US, cases of AI infection have been confirmed in 36 states, including Texas, Georgia, Wisconsin, Minnesota, and Iowa. AI infection was confirmed in a total of 372 bird flocks, and it is estimated that regarding 40.09 million birds were infected.
AI is an acute viral infectious disease that occurs when birds such as chickens, ducks, and migratory birds are infected with the ‘H5N1’ virus. It is spread through the air, is respiratory, and rarely in humans. According to the severity of the disease, it is divided into high pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI). This is because the rapid propagation speed causes great damage to birds.
HPAI was first discovered in a Chinese goose in 1996 and has since evolved through hosts around the world. It caused a large-scale outbreak in China in 2005 and first appeared in North America in 2014. Now, it has become an epidemic that occurs frequently in the United States, and is occurring every one to three years, including in Korea. In Korea, since the first outbreak of HPAI in 2003, millions to tens of millions of chickens have been culled with each epidemic. No vaccine or treatment has been developed. That is why bird killing is the only way to combat HPAI. However, recently, the scale of the HPAI epidemic has grown to the extent that it cannot be dealt with only by killing, and the concerns of quarantine authorities are deepening.
○ Threats even to humans… AI monitoring system needs to be overhauled
The AI that is spreading in the United States this time is blamed for a black-backed gull that flew from Europe to eastern Canada last winter. This is the first time that a black-backed gull has been confirmed to be infected with a highly pathogenic virus. With a wingspan of 2.5 m, the black-backed gull can cross the Atlantic Ocean in one day. This means that the virus can spread easily. The scientists analyzed that the pattern of spread is complicated by the exposure of more and more bird species to the infection. In addition, as highly pathogenic viruses evolve in a direction favorable to infection, it is believed that the scale of the epidemic is growing. Nicola Hill, a professor of biology at the University of Massachusetts, USA, and his research team said, “The spread of highly pathogenic viruses in wild birds is increasing as the number of cases in which they are infected increases.”
Cases of infection in humans and mammals are also increasing. The Wisconsin Department of Natural Resources announced on the 31st of last month that a population of red foxes tested positive for HPAI. In addition to Wisconsin, infected foxes have also been identified in Minnesota, Iowa, Michigan and Ontario, Canada. It is believed that the virus was transmitted following eating infected birds. As a result, other bird-eating species, such as rabbits and skunks, are expected to be infected.
On April 28, a case was reported in the United States of a person infected with HPAI following contact with birds. Including this case, there have been 880 human infections worldwide since 2003. The U.S. Centers for Disease Control and Prevention said, “The virus is spread by the saliva, mucus, and feces of birds infected with HPAI. he explained.
Experts stress the need for greater investment in research into bird behavior. It is necessary to preemptively prevent infection and spread of highly pathogenic viruses by identifying behavioral patterns. “In order to improve our understanding of HPAI and prevent its spread, we need to study the behavior of wild birds and establish a monitoring system,” said Professor Hill.
Ko Jae-won, staff reporter for Donga Science jawon1212@donga.com
