Avian influenza

Avian influenza

Pertaining to owners of livestock Analisa Aguirre, Emily Serrano, Paris Alba

Start

What is Avian Influenza?

• Avian infleunza (bird flu), is a contagious viral disease of domestic and wild birds caused by influenza A viruses
• Cause sporadic human infections worldwide
• Very different from human seasonal influenza virus
• Most human cases in the U.S. have been mild
• Major threat to the poultry industry, animal health trade, and economy

History

1878

1971

1955

Hosts

Natural Hosts

• Wild aquatic birds: gulls, terns, shorebirds
• Wild waterfowl: suck, geese, swans
• Some wild birds can be infected and show no signs of illness

Other Hosts

• Mammals: dairy cows, raccoons, skunks, foxes
• Marine mammals: seals, sea lions
• Domesticated animals: dogs and cats

Trasmission

Virus can be spread through:

• Close contact between infected and healthy birds
• Most common means of bird-to-bird transmission

• Biological secretions and/or excretions from birds
• Nares, mouth, & eyes
• Contact with contaminated equipment/animal by-products
• Clothing, boots, vehicles, etc.
• Humans can become infected by touching surfaces contaminated with bird mucus, saliva, or feces & then touching their eyes

Transmission cont.

• Airborne secretions
• Especially in poultry houses
• Cannot travel long distances in the air
• Small dust particles containing the virus get expelled in the air
• Movement of infected animals

• Mammalian species may become infected by eating sick/dead infected birds
• The closer a human is to a live, sick, or dead, bird, cow, or other animal, the more likely they are to become infected
• Humans can get the virus by not wearing proper PPE
• No person-to-person spread has been identified in the U.S.
• Concerns that virus may mutate
• Public health risk is low, CDC is monitoring
• ZOONOTIC!

Subtypes

• Subtypes of avian influenza A viruses known to cause human infections include: H5, H6, H7, H9, and H10 viruses
• Can be further divided based on two proteins on the surface of the virus: hemagglutinin (HA) and neuraminidase (NA):
• Many different combinations of HA and NA proteins are possible
• In birds, 16 HA and 9 NA substypes have been identified

Why is it important?

Owners of Livestock

Overall

• The current global outbreak of HPAI is causing high mortality rates in poultry
• Population effects
• Widespread in wildlife birds worldwide

• Threatening food security and global food supply chains
• Egg shortages
• Potential for the virus to mutate to easily spread from person-to-person

• In the event of an outbreak, policy often results in the slaughtering of all poultry
• Results in measures being taken, especially within mass production agencies

• Causes massive economic losses for farmers who are affected

Signs and Symptoms: in birds

Highly Pathogenic Avian Influenza A Virus (HPAI):

• Cause severe disease and high mortality
• 90-100% mortality in 48 hours
• Deadly to domestic poultry and can kill an entire flock within days
• Symptoms:
• Sudden death
• Lack of energy/appetite
• Drop in egg production
• Difficulty breathing
• Nasal discarge, coughing, sneezing
• Lack of coordination
• Hemorrhages on unfeathered parts of legs
• Diarrhea

Signs and Symptoms: in birds cont.

Low Pathogenic Avian Influenza A Virus (LPAI):

• Causes either no signs of disease or mild disease
• Most influenza A(H5) and A(H7) viruses among birds are LPAI
• Symptoms:
• May see respiratory distress

• Decreased egg production
• Ruffled feathers
• Decreased feed production

Signs and Symptoms: in humans

Mild signs and symptoms:

• Conjunctivitis
• Mild fever (100° or higher)
• Cough, runny nose
• Sore throat
• Muscles/body aches
• Fatigue

Moderate to severe signs and symptoms:

• High fever
• Shortness of breath
• Seizures

Complications

• Pneumonia
• Respiratory failure
• Multi-organ failure
• Sepsis
• Inflammation of brain

Signs and Symptoms: dairy cattle

• Low appetite
• Reduction in milk production
• Abnormal appearance of milk (discolored)
• Clear nasal discahrge
• Loose feces
• Dehydration
• Fever
• Lethargy

Diagnosis

• ACAI:
• Effective flock-based screening tool
• Lower sensitivity than molecular assays
• Highly specific when used on clinically ill/dead birds
• Direct RNA detection:
• Involves rRT-PCR to detect influenza A and H5/H7 subtypes in specimens
• Sequencing/virus isolation is then performed
• Virus isolation:
• There may be a delay in obtaining results

Treatment

Birds:

• No treatment for HPAI, the only way to stop the disease is to depopulate
• For LPAI, quarantine animals
• If a poultry flock is affected, quarantine and limmit exposure to birds

Humans:

• People with symptoms might be prescribed antiviral treatment with Oseltamivir
• Tamiflu
• Works best witin 48 of developing symptoms
• Should not be considered a substitute for implementing prevention measures

Vaccine:

• At this time, there is no commercially available vaccine

Prevention

Overall

Farming Methods

Best way to prevent avian influenza is to avoid sources of exposure

• Avoid direct contact with sick/dead wild birds
• Wear recommended PPE
• Do not touch surface materials contaminated with saliva, mucus, or animal feces
• Do not touch or consume raw milk/raw milk products
• Cook poultry, eggs, and beef to a safe internal temperature to kill bacteria and viruses
• Early recognition is important to stop the spread
• Biosecurity is the first line of defense against transmission

In addition to the other provided methods, there are other things to be mindful of if you own poultry

• 6 steps to keep your birds safe

• Keep your distance
• Keep their grazing area clean
• Don't haul disease home
• Don't borrow from your neighbor
• Dnow the signs
• Report sick birds
• Be aware of wild bird migration and prevent interaction with domestic birds
• Always use PPE if ever in the event of the removal of a dead bird

Citations

1. About bird flu. 2024a. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/about/index.html. 2. Avian influenza - background. (n.d.). . Retrieved March 20, 2026, from https://www.osha.gov/avian-flu/background. 3. Avian Influenza. 2026. . Retrieved March 20, 2026, from https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza. 4. Bird flu: Causes and how it spreads. 2025a. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/virus-transmission/index.html. 5. Four reasons why avian influenza should be on your Radar. (n.d.). . Retrieved March 20, 2026, from https://www.fao.org/newsroom/story/four-reasons-why-avian-influenza-should-be-on-your-radar/en. 6. Highlights in the history of avian influenza (bird flu). (n.d.). . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/avian-timeline/index.html. 7.Influenza (avian and other zoonotic). 2026. . World Health Organization. Retrieved March 20, 2026, from https://www.who.int/news-room/fact-sheets/detail/influenza-%28avian-and-other-zoonotic%29. 8. People at increased risk for Bird Flu. 2025b. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/risk-factors/index.html. 9. Preventing bird flu infections. 2025c. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/prevention/index.html. 10. Signs and symptoms of bird flu in people. 2024b. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/signs-symptoms/index.html. 11. Treatment of bird flu. 2025d. . Centers for Disease Control and Prevention. Retrieved March 20, 2026, from https://www.cdc.gov/bird-flu/treatment/index.html. 12. ———. (n.d.). . Retrieved March 20, 2026, from https://www.avma.org/resources-tools/animal-health-and-welfare/animal-health/avian-influenza. !

Citations

Picture Citations

• https://avinews.com/wp-content/webp-express/webp-images/doc-root/wp-content/uploads/2024/04/Portada-ZUCAMI.jpg.webp
• https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs44298-024-00039-z/MediaObjects/44298_2024_39_Fig1_HTML.png
• https://www.abcdcatsvets.org/guideline-for-influenza-virus-infections-in-cats/
• https://www.bivatec.com/blog/avian-influenza-fowl-plague-and-bird-flu-in-poultry
• https://www.drlogy.com/health/bird-flu-symptoms?srsltid=AfmBOopUoyTTJ52pHkvIq7A-1wmxMRRC6tg7M2wGnVWaNjyv2SFVP-Jy
• https://images-provider.frontiersin.org/api/ipx/w=1200&f=png/https://www.frontiersin.org/files/Articles/386938/fimmu-09-01812-HTML/image_m/fimmu-09-01812-g001.jpg
• https://www.poultryworld.net/app/uploads/2023/12/LAMP-test-photo-848x565.jpg
• https://image.slidesharecdn.com/1918-flu-epidemic-210514141119/85/1918-Flu-Epidemic-3-320.jpg