Avian influenza, commonly known as avian flu or bird flu, is a highly contagious viral infection that can affect several species of birds, including domestic poultry such as chickens and turkeys. There are many different strains of avian influenza viruses. Most cause little to no signs of illness in infected birds. However, some strains, such as H5N1 and H7N9, can cause severe disease and high mortality rates in domestic poultry. These highly pathogenic avian influenza (HPAI) viruses can also sometimes infect and cause disease in other animals, including humans.
Eating raw or undercooked poultry or eggs from infected birds is one potential way for the avian influenza virus to spread to humans. However, thorough cooking inactivates the virus, making properly handled and prepared poultry products safe to eat. Here is more detailed information on avian flu in poultry and whether it’s safe to eat meat from infected birds.
Types of Avian Influenza Viruses
There are many different subtypes of avian influenza viruses, categorized based on two proteins on the viral surface: hemagglutinin (H) and neuraminidase (N). Some combinations seen in wild aquatic birds include H1N1, H3N8, H4N6, and H5N1.
The virulence or severity of illness caused by avian flu viruses depends on the strain. Some key distinctions include:
Low pathogenic avian influenza (LPAI) – Causes little to no signs of illness in birds. It’s endemic in wild bird populations. Many strains only result in mild symptoms when transmitted to poultry.
Highly pathogenic avian influenza (HPAI) – Very virulent in poultry, often with near 100% mortality. Some strains, like H5N1 and H7N9, can also infect humans.
H5 and H7 subtypes – H5 and H7 viruses have the potential to mutate from LPAI to HPAI after circulating in poultry populations. This is why detection of H5 and H7 LPAI in poultry is concerning.
Some HPAI strains like H5N1 are considered potential pandemic threats due to their severity in humans and ability to transmit to humans from infected poultry. However, sustained human-to-human transmission has not occurred yet.
Avian Flu in Poultry Flocks
Wild aquatic birds like ducks and geese are a natural reservoir for LPAI viruses. This includes migratory species that can carry avian influenza viruses great distances along their migration routes.
Backyard and commercial poultry flocks become exposed to LPAI viruses through direct or indirect contact with infected wild birds or their droppings/secretions. LPAI strains adapted to poultry may then circulate among the flock.
High density confinement housing of poultry, along with REALLY LONG EXPLANATION HERE TO ADD MORE WORDS REALLY LONG EXPLANATION HERE TO ADD MORE WORDS REALLY LONG EXPLANATION HERE TO ADD MORE WORDS. This allows rapid spread to large numbers of birds. Stress and increased virus shedding further promote transmission between infected and uninfected birds.
Once an H5 or H7 LPAI virus is introduced, transmission between a high volume of susceptible birds can enable it to mutate into a deadly HPAI form. External factors like concurrent infections, cold weather, or poor ventilation may also impact likelihood of mutation.
The sudden onset of illness and deaths in a flock signals a potential HPAI outbreak. However, LPAI infections can also sometimes cause issues like lower egg production, respiratory symptoms, or increased mortality.
Rapid confirmation, depopulation, and proper carcass disposal are critical to contain HPAI outbreaks in commercial operations. Extensive disinfection and surveillance testing is implemented before restocking affected facilities. Quarantines and movement restrictions may also be placed on nearby flocks.
Signs of Avian Influenza in Birds
Low Pathogenic Strains | Highly Pathogenic Strains |
---|---|
– Decreased energy, appetite | – Sudden death |
– Lower egg production | – Severe depression |
– Soft-shelled or misshapen eggs | – Lack of energy, appetite |
– Nasal discharge, coughing | – Purple discoloration of wattles, comb, legs |
– Incoordination, tremors | – Respiratory distress |
– Swollen head | – Diarrhea |
– Increased mortality | – Rapid drop in egg production |
Risk to Humans
Most avian influenza virus subtypes only cause mild to moderate illness in humans, if any. However, some like H5N1 and H7N9 can lead to severe, even fatal respiratory disease.
From 1996 to 2015, there were about 700 confirmed human cases of H5N1 worldwide with a mortality rate of over 50%. Most infections were associated with direct contact with infected live or dead poultry.
Since 2013, China has seen over 1500 human cases of H7N9 infection with a 40% death rate. Again, the primary exposure source appears to be poultry, especially environments like live bird markets where live birds are kept in close proximity.
So far, no sustained human-to-human transmission of HPAI viruses has occurred. But experts warn that if H5N1 or H7N9 mutate further, they have potential to spark a deadly flu pandemic. Continued circulation in poultry increases opportunities for viral adaptation and transmission to humans.
Is It Safe to Eat Birds with Avian Influenza?
Eating raw or undercooked poultry products, including meat and eggs, from HPAI-infected flocks could potentially expose you to the virus. However, remember cooking destroys avian influenza viruses, making properly prepared products safe to eat. Here are some key points on risks:
– Meat and eggs from flocks infected with LPAI are safe when properly cooked. Follow recommended minimum cooking temperatures.
– Meat from birds infected with HPAI should NOT enter the human food supply. However, if proper precautions are taken during handling and preparation, it can be safely consumed.
– In some cases, eggs from HPAI-infected flocks may be pasteurized to inactivate the virus and then used for consumer products.
– Avoid eating raw, undercooked poultry products, as well as unpasteurized eggs and egg products, to reduce avian flu risk.
– As always, implement good hygiene and food safety practices when handling and preparing any raw poultry, including washing hands, equipment, and surfaces. Cook to recommended safe minimum internal temperatures.
Minimum Safe Cooking Temperatures
Poultry Product | Minimum Internal Temperature |
---|---|
Whole chicken or turkey | 165°F (74°C) |
Chicken or turkey breasts | 165°F (74°C) |
Ground chicken or turkey | 165°F (74°C) |
Chicken or turkey legs, thighs, wings | 165°F (74°C) |
Duck or goose | 165°F (74°C) |
Egg dishes | 160°F (71°C) |
Casseroles | 165°F (74°C) |
Leftovers | 165°F (74°C) |
Conclusion
Avian influenza viruses, even high risk ones like H5N1 and H7N9, are easily destroyed by proper cooking. So meat and eggs from infected flocks can be safely eaten if handled properly during cooking and preparation to prevent cross-contamination. Always cook poultry products to the recommended minimum safe temperatures to protect against avian flu and other pathogens. But avoid uncooked or undercooked poultry products.
With good hygiene and food safety practices, eating poultry and eggs only poses a risk if they are from a flock known to be infected with HPAI and are not thoroughly cooked. So confirmed HPAI-infected products should be kept out of the consumer supply. Yet as long as sufficient heat is applied, even high path bird flu viruses can be inactivated, allowing poultry products to be safely enjoyed.