|
|
|
|
|
Avian Influenza: Egg
Economics, Transmission, Prevention Approaches |
|
Author:
Madeline M. Roberts, MPH, PhD
Low pathogenicity avian influenza (LPAI) has minimal or no clinical signs among infected poultry. By contrast, Highly Pathogenic Avian Influenza (HPAI) is severe and often fatal among poultry; it is also highly contagious and necessitates rapid intervention to mitigate impact. Over the past two decades, outbreaks of several different strains of avian influenza (both LPAI and HPAI) have occurred. For H5N1 specifically, a total of 868 human infection cases and 457 deaths were reported globally from 2003-2022 for a sobering case fatality rate of 53%. One case was reported in the United States by Colorado in late April 2022. This individual was directly involved in the depopulating of presumptively infected poultry, was treated with oseltamivir, and recovered. It was subsequently reported that this may not have been a systemic infection, but rather nasal passages contaminated with the virus. Early this month, a nine-year-old girl with no known comorbidities in Ecuador was admitted to the ICU in critical care and placed on a mechanical ventilator after developing a severe case linked to contact with infected poultry in her backyard.
As for the grocery store
sticker-shock on a carton of eggs, this household staple has been subject
to a confluence of factors—inflation,
increased feed and transportation costs, and of course the fallout of
the avian influenza that has been surging since 2022. U.S.
egg inventories dropped 29% from the beginning of 2022 to its close.
Inflation is beginning to decelerate, and
egg prices per dozen are down from the 2023 high, so our eyes are on
how long it takes to replenish flocks (some estimate
four to six months), and the bigger question, how the current outbreak
trends. There is at least
one account of a Colorado facility euthanizing its flock due to viral
infection then restocking its flock, only to again detect the virus, which
necessitated euthanizing the new flock. It is difficult to overstate the
impact on this sector. As a reference point, the economic impact of the
Highly Pathogenic Avian Influenza (HPAI) 2014-2015 U.S. outbreak was
estimated in excess of
$3 billion |
|
|
|
Briefly, a few approaches to curb the impact of avian flu include antivirals, poultry vaccination programs, selective breeding for disease resistance, and in more experimental contexts, genetic engineering. Antivirals, while effective, can be cost-prohibitive for entire flocks and may facilitate drug-resistant mutations. Poultry vaccination programs, utilized in several countries such as Egypt and Nepal, are helpful for mitigating spread. Large-scale poultry vaccination presents implementation challenges and also necessitates regular updates as viruses mutate. Vaccination can also can have economic implications as some countries prohibit imports of vaccinated poultry. Perhaps the most controversial approach, which has a growing body of research, is genetic modification to engineer poultry resistant to Influenza A virus (IAV). A somewhat more moderate alternative is selective breeding for IAV-resistant poultry. Selective breeding for other traits (for example, higher egg yield) is already current practice within the industry for many facilities. Poultry-to-Human Transmission Poultry-to-human transmission typically occurs through direct contact with the bodily fluids (feces, mucus, saliva) of infected birds, though transmission is also possible via dust or droplets in the air. Find a helpful infographic on poultry-to-human transmission here. The virus is heat-sensitive thus, appropriately cooked (165˚F internal temperature) poultry and game birds are safe for consumption. Transmission Among Mammals Avian influenza remains relatively ill-suited to humans, and person-to-person spread is uncommon and unsustained. Risk among humans has been and continues to be assessed as low. However, there have been recent reports, within the U.S. and globally, of transmission to mammals including bears, mink, otters and foxes. Virus mutation always remains a reality, and as such, epidemiologists may be holding our collective breath as this situation continues to play out. In the meantime, the World Health Organization advises surveillance and thorough investigation of all zoonotic infections, as well as preparedness planning. ■ |
|
|
|
|
