Today, the United Nation Food and Agriculture Organization (FAO) warned of a possible major resurgence of H5N1 Highly Pathogenic Avian Influenza due to the spread of a mutant form of the virus in Asia and beyond. The mutation defeats the current avian influenza vaccination, taking away an important weapon in the battle to prevent H5N1’s spread. FAO is calling for “heightened readiness and surveillance.”
FAO reports that Vietnam’s veterinary services are on “high alert” for the disease. The presence of the mutated H5N1 in Vietnam poses a threat to nearby countries like Cambodia, Thailand, Malaysia as well as Korea and Japan. Wild birds may carry the mutated strain along migration routes and thereby spread this dangerous virus throughout Asia.
After its identification in 2003, H5N1 spread to birds in 63 countries, but aggressive culling of infected flocks eliminated it from many of those locations. Despite these efforts the virus remained endemic in Bangladesh, China, Egypt, India, Indonesia and Vietnam. Mutated H5N1 has been found in China and Vietnam. Since 2008, the outbreaks in wild and domestic birds has been increasing and expanding; H5N1 has been detected recently in Israel and the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia.
On 14 August, a six-year-old in Cambodia became the most recent fatality, the eighth case there this year; all eight died. Cambodia has had 18 confirmed cases since 2005, and 16 were fatal. Of the 565 known human cases worldwide, over half have died. In addition to the human toll, H5N1 has caused $20 billions in economic damage worldwide. Its spread could also threaten food security for vulnerable populations.
Q&A on Avian Influenza
Is all bird flu scary?
There are different strains of influenza circulating at any given time. Just like people can get “seasonal flu” (which is actually a few different strains) or “swine flu/H1N1” (a single strain that appeared in 2009), birds can get different types of influenza. The H5N1 strain that FAO is concerned about is very contagious and causes high death rates among birds. It has also killed more than half of the people who caught it. This strain is very concerning and the FAO’s call for more surveillance is prudent. When newspaper headlines refer to “bird flu,” they normally mean H5N1 specifically.
Is H5N1 an immediate threat to my family?
Almost certainly not. Studies show that risk factors for H5N1 infection involve close contact with infected birds (preparing sick or dead poultry or having sick or dead poultry in the household). The people at risk for this disease are those who live in countries where the disease in endemic (entrenched) and handle poultry regularly. See the map above (or click here) to see what countries have had H5N1 deaths in humans.
I heard about a farm having a low-path bird flu outbreak.
What does that mean? When veterinarians or farmers talk about infections in a flock, they may talk about low-path and high-path strains. Path is short for pathogenicity. A low-path strain just gives the birds a mild cold while a high-path strain may kill 90-100% of the birds.
Low-pathogenicity H5N1 is also called “‘North American’ H5N1.” It is common in wild birds, is not a significant threat to humans, and almost never appears in newspaper articles. High-pathogenicity H5N1 is also called “‘Asian’ H5N1” and is often fatal to poultry. This type of H5N1 is the one that can also infect humans.