Bird Flu: Symptoms, Diagnosis, and Treatment

Bird flu is a disease that can cause severe respiratory issues, sometimes even leading to death. Fortunately, human cases are very rare. Learn more in this article!
Bird Flu: Symptoms, Diagnosis, and Treatment

Last update: 27 May, 2022

Viruses are infectious agents capable of invading most living organisms. Birds can be affected by influenza viruses that are transmitted among birds and remotely to humans. That’s where bird flu comes in.

Are you interested in learning about bird flu, or avian influenza?

Today, we’ll talk about its symptoms, diagnosis, and treatment.

Bird flu, or avian influenza, is a disease caused by the Type A influenza virus. It spreads among poultry through saliva, mucous secretions, and feces. However, there have also been reports of human cases. The World Health Organization (WHO) recorded 2 cases in China in 2017.

Currently, experts have identified more than 12 different strains of the virus, but only three of them have affected humans. However, continued mutations could increase the rate of infection in humans in the long term.

What are the symptoms of bird flu?

Clinical manifestations usually appear 2 to 7 days after exposure to the avian influenza virus. Symptomatology varies from mild to severe and life-threatening conditions.

In most cases, it usually resembles the common flu, presenting the following symptoms:

  • Cough
  • Respiratory distress
  • Fever
  • General malaise
  • Sore throat
  • Nasal congestion
  • Muscle and joint aches
  • Unexplained tiredness
  • Red eyes with increased tearing

Mild cases usually include gastrointestinal symptoms, such as nausea, vomiting, diarrhea, and abdominal pain. At the same time, a smaller proportion of patients with avian influenza may have an unfavorable course and present with the following conditions:

  • Acute respiratory failure
  • Pneumonia
  • Altered state of consciousness
  • Convulsions
A woman lying in bed with a fever, taking her temperature.
The most characteristic flu symptoms are fever and extreme fatigue with muscle pain.

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What’s the cause of bird flu?

The agent responsible for avian influenza is the type A influenza virus in its different mutagenic variants. Experts have identified the H5N1, H7N9, and H5N6 strains in humans, H5N1 is the most studied. More than 165 cases of avian influenza were attributed to the latter between 2003 and 2006, with a case fatality rate of more than 50%.

Infection in humans occurs when the virus comes into contact with the mucous membranes of the eyes, nose, or mouth, or through inhalation of droplets or dust containing the virus. In addition, direct contact with infected birds greatly increases the likelihood of infection.

Likewise, studies have shown that person-to-person transmission is very low and usually occurs through intrafamilial contact. On the other hand, the great capacity of the virus to adapt to humans creates concern about the possible incidence of a new, more contagious strain in the future.

Risk factors

The main risk factors that experts have associated with the occurrence of bird flu in humans have to do with continuous exposure to infected domestic and wild birds. These include chickens, turkeys, ducks, and geese.

Therefore, the incidence of this disease is higher in the following scenarios:

  • Work and activities with poultry
  • Overcrowding and insalubrity in stores and markets selling poultry products
  • Travel to Middle Eastern countries where there’s a higher incidence
  • Contact with secretions, feces, and feathers of infected birds
  • Consumption of poultry meat and eggs that haven’t been properly cooked

In addition, according to estimates, 90% of patients with avian influenza are under 40 years of age, with a higher mortality rate in young people between 10 and 19 years of age.

Diagnosis of avian influenza

Identification of avian influenza infection in humans requires the assessment of symptoms and signs associated with laboratory diagnostic tests. The Center for Disease Control and Prevention (CDC) recommends taking nose and throat swabs in the first few days.

Specialized laboratories will receive these samples, where they’ll identify the agent by molecular testing or virus culture. Similarly, in patients with severe manifestations, doctors should take lower respiratory tract samples to confirm the viral etiology.

In some patients, the determination of antibodies against influenza virus type A is useful. For this purpose, specialists take two blood samples; one at the onset of symptoms and another after 3 or 4 weeks. It’s important to take into account that the results take several days.

The specialist can rely on imaging methods, such as chest radiography, to determine the involvement of the bronchopulmonary tree. Likewise, this study allows them to evaluate what attitude and the therapeutic protocol to follow.


The treatment of bird flu aims at alleviating the symptoms and eliminating the viral agent responsible. The use of neuraminidase inhibitor antivirals is effective in some cases. These drugs block the release of the virus from infected cells and its colonization of the rest of the cells.

Most strains of influenza virus type A and B are susceptible to oseltamivir or Tamiflu®, peramivir and zanamivir or Relenza®. However, the CDC has reported some resistance to these drugs by some mutations of H5N1 and H7N9 strains in Asian patients.

Therapeutics include adequate fluid replacement and the use of antipyretic and analgesic drugs to reduce associated symptoms.

Recovery from bird flu

The course of the disease will depend on the strain of the virus affecting the individual and the degree of respiratory involvement. In general, patients usually have a good prognosis. However, some experience complications and require special measures.

During the course of infection by avian influenza, it’s advisable to follow the indications below:

The disease usually subsides after a couple of weeks of treatment. However, if the patient notices any new signs or worsening of symptoms, it’s crucial to seek immediate medical attention.

A dehydrated woman in a hospital bed.
Severe cases require hospitalization for the support of basic vital signs and the administration of antivirals.

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Prevention of avian influenza

When it comes to the prevention of avian influenza, methods aim at reducing or eliminating the risk factors associated with infection. In this regard, the main measure’s to avoid any form of exposure to the virus.

For this purpose, the following recommendations can be followed:

  • Avoid contact with wild poultry or aquatic birds.
  • Don’t touch surfaces or objects that may contain bird feces or secretions.
  • Wash hands with plenty of soap and water when touching contaminated surfaces or items.
  • Use masks and protective suits when working with birds, especially in enclosed areas.
  • Avoid consuming eggs without proper hygiene and cooking.
  • Also, cook poultry meat to a minimum internal temperature of 167 degrees Fahrenheit.

At the same time, people who decide to visit countries with a potential risk of avian influenza infection should avoid open-air and unsanitary markets. In addition, poultry products that are poorly processed shouldn’t be consumed.

As for vaccines, the administration of seasonal influenza immunization doesn’t prevent the risk of infection, but it does reduce the incidence of viral co-infection. For example, the United States currently has a stockpile of a vaccine against the H5N1 strain of Asian origin; however, it wouldn’t be effective against possible mutation.

Don’t underestimate a bird flu infection

To conclude, the symptoms of bird flu are usually diffuse and tend to be confused with those present in other forms of flu or influenza. However, it’s vital to see a medical specialist early to determine the positive course of the disease.

In some patients who don’t receive treatment in time or receive inadequate treatment, lethal complications may appear. If there’s evidence of severe respiratory distress or worsening of symptoms, you should consult an emergency center as soon as possible.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.