Avian flu: symptoms, diagnosis and treatment

Viruses are infectious agents capable of invading most living things. Birds can be affected by influenza viruses that are transmitted between birds and remotely to humans. Are you interested in knowing what bird flu is, its symptoms, diagnosis and treatment? Next we will tell you.

Avian flu or avian influenza is a disease caused by the type A influenza virus. It is spread among poultry through saliva, mucous secretions and feces. However, human cases have been reported. The World Health Organization (WHO) recorded 2 cases in China in 2017.

Currently, more than 12 different strains of the virus have been identified, but only 3 of them have affected people. However, ongoing mutations could increase the human infection rate in the long term.

What are the symptoms of bird flu?

Clinical manifestations usually appear 2 to 7 days after exposure to the virus from avian flu. Symptoms vary from mild conditions to serious life-threatening alterations.

In most cases, it tends to resemble the common flu, presenting the following symptoms:

  • Cough.
  • Shortness of breath
  • Fever.
  • General discomfort.
  • Throat pain.
  • Nasal congestion.
  • Muscle and joint pain
  • Inexplicable tiredness
  • Reddened eyes with increased tears.

Mild cases are often accompanied by gastrointestinal manifestationssuch as nausea, vomiting, diarrhea, and abdominal pain. On the other hand, a smaller proportion of patients infected by avian flu may have an unfavorable evolution and present the following conditions:

  • Severe respiratory insufficiency.
  • Pneumonia.
  • Alteration of the state of consciousness.
  • Seizures

The most characteristic flu symptoms are fever and extreme fatigue with muscle pain.

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What is the cause?

The agent responsible for avian flu is the type A influenza virus in its different mutagenic variants. Strains H5N1, H7N9 and H5N6 have been identified in humans, with H5N1 being the most studied. More than 165 cases of bird flu were attributed to the latter between 2003 and 2006, with a 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 by inhaling drops or dust containing it. Furthermore, direct contact with infected birds greatly increases the likelihood of infection.

Similarly, it has been shown that person-to-person transmission is very low and, generally, it occurs through family contact. On the other hand, the great adaptability of the virus to humans raises concern about the possible incidence of a new, more contagious strain in the future.

Risk factor's

The main risk factors associated with the presentation of avian influenza in humans are related to continued exposure to infected domestic and wild birds. Among them are chickens, turkeys, ducks and geese.

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

  • Work and activities with poultry.
  • Overcrowding and unsanitary conditions in shops and markets for poultry products.
  • Travel to Middle Eastern countries where there is a higher incidence.
  • Contact with secretions, feces and feathers of infected birds.
  • Consumption of undercooked poultry and eggs.

In addition, it is estimated that 90% of patients with avian flu are under 40 years of age, with a higher mortality in young people aged 10 to 19 years.

Avian Flu Diagnosis

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

The extracted samples will be sent to specialized laboratories, where the agent will be identified by molecular testing or by culture of the virus. Similarly, in patients with severe manifestations, lower respiratory tract samples should be taken to confirm viral etiology.

In some patients, determination of antibodies against influenza virus type A. For this, two blood samples are taken; one at the beginning of symptoms and another after 3 or 4 weeks. It should be considered 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. Similarly, this study makes it possible to assess the attitude and the therapeutic protocol to be followed.


The treatment of avian influenza is aimed at alleviating the symptoms and eliminating the responsible viral agent. The use of antiviral neuraminidase inhibitors is effective in some cases. These drugs block the release of the virus from the infected cells and the colonization of the rest of the cells.

Most strains of influenza A and B viruses 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 the H5N1 and H7N9 strains in Asian patients.

Similarly, therapy includes adequate fluid replacement and the use of antipyretic and analgesic drugs to reduce associated symptoms.

Recovering from bird flu

The evolution of the disease will depend on the strain of virus that affects the person and the degree of respiratory compromise. As usual, patients usually have a good prognosis. However, some are complicated and require special measures.

During the course of infection with avian flu it is advisable to follow the following guidelines:

  • Consume plenty of fluids.
  • Avoid cold drinks.
  • Ventilate the recovery room or room.
  • Use a mask.
  • Rest and keep complete rest.

The disease usually subsides after a couple of weeks of treatment. However, if the patient observes any new signs or the symptoms worsen, it is crucial to seek medical assistance immediately.

Severe cases require hospitalization for support of basic vital signs and administration of antivirals.

Read also: Flu in older adults: symptoms, treatments and complications

Avian Flu Prevention

Avian flu prevention methods are aimed at reducing or eliminating risk factors associated with infection. In this sense, the main measure is to avoid all forms of exposure to the virus.

For this, the following recommendations can be followed:

  • Avoid contact with poultry or wild aquatic.
  • Do not touch surfaces or objects that may contain bird feces or secretions.
  • Hand washing with plenty of soap and water by touching contaminated surfaces or items.
  • Wear protective masks and suits when working with birds, especially indoors.
  • Avoid eating eggs without proper cooking and hygiene.
  • Cooking poultry until reaching a minimum internal temperature of 75 degrees Celsius.

On the other hand, people who decide to visit countries with a potential risk of infection by bird flu should avoid unhealthy open air markets. In addition, poorly processed poultry products should not be consumed.

Regarding vaccines, the administration of immunization against seasonal influenza does not prevent the risk of contagion, but it does reduce the incidence of viral coinfection. Currently, the United States has a reserve of vaccines against the H5N1 strain of Asian origin, however, it would not be effective in the face of the possible mutation.

Bird flu infection should not be underestimated

Symptoms due to avian flu are usually diffuse and tend to be confused with the present in other forms of flu or influenza. However, it is vital to go to the specialist doctor early to determine the positive course of the disease.

In some patients who are not treated in time or are treated in an inadequate way, lethal complications can appear. Faced with evidence of severe respiratory distress or worsening of symptoms, go to an emergency center as soon as possible.