Rarely seen in the United States, bird flu is a type of influenza that can be passed from birds to humans.
Bird flu, or avian flu, is a contagious viral disease that mainly affects birds.
Most bird flu viruses do not infect humans, but some strains – especially H5N1 and H7N9 – can cause severe infections in people in rare cases.
Bird flu is transmitted to humans through direct or indirect exposure to live or dead birds infected with the virus, such as by working with poultry (farming) or by eating raw or undercooked meat, blood, or eggs.
Signs and Symptoms of Bird Flu
According to the World Health Organization (WHO), the H5N1 and H7N9 bird flu viruses cause symptoms 2 to 3 days and 2 to 8 days after exposure, respectively.
In some cases, viruses only cause conjunctivitis (pink eye), but they often cause flu-like symptoms, including:
Fever greater than 100.4 degrees F (38 degrees C)
Cough
Sore throat
Diarrhea
To vomit
Stomach pain
Chest pain
Bleeding from the nose and gums
Headache
In many cases, the virus spreads to the lower respiratory tract, causing pneumonia, which can result in:
Difficulty breathing
A loud voice
Cracking sound while breathing
Coughing up mucus or blood
Bird flu can also cause other infections and complications, such as:
Hypoxemia (blood oxygen)
Respiratory failure
Multiple organ failure and failure
Sepsis (blood infection)
Secondary bacterial and fungal infections, especially bacterial pneumonia
Treatment and Medication Options for Bird Flu
In humans, bird flu is usually treated with one of the few antiviral drugs, including Tamiflu (Ocetamivir), Paramivir, and Zanamvir, which reduce the virus’s ability to replicate.
Oseltamivir is in pill form, while paramyvir is an intravenous (IV) drug, and zanamivir is inhaled as a powder.
However, according to the Centers for Disease Control and Prevention (CDC), some strains of the H5N1 and H7N9 viruses have shown resistance to antiviral drugs.
In 2007, the CDC approved a vaccine for H5N1. But the vaccine is not commercially available to the public, and instead is being stockpiled by the CDC in the event of a national bird flu emergency.
In May 2015, Kansas State University researchers announced the development of H5N1 and H7N9 vaccines for birds, according to the Journal of Virology.
Bird Flu Outbreaks
The H5N1 bird flu virus first infected humans in 1997 during a bird flu outbreak in China, and became widespread in 2003 and 2004.
According to the CDC, in total, it has caused more than 700 infections in 15 countries, with a mortality rate of about 60 percent.
Indonesia, Vietnam and Egypt have the most human H5N1 infections, and no one in the United States.
In 2014, the first human H5N1 infection in Canada occurred in the United States, in a person who recently returned from China.
According to the WHO, the H7N9 bird flu virus first infected three people in China in 2013.
Of the 571 laboratory-confirmed human cases of H7N9 now, 568 occurred inside China, one in a Chinese traveler going to Malaysia, and two in Canada among people returning from China.
Although there have been no human cases of H7N9 or H5N1 in the United States, there have been other types of bird flu infections in humans.
For example, in 2002, a poultry farmer in Virginia became infected with H7N2. In 2003, a man in New York contracted the H7N2 virus.
