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Bird Flu: Causes, Symptoms, Risk Factors, Diagnosis And Treatment

Bird flu also called avian influenza is an infectious disease of birds caused by type A strains of the influenza virus [1]. The infection can result in the development of symptoms in birds, ranging from a mild illness to a rapidly fatal epidemic.

Since February 2020, India has been reporting an increasing number of bird flu cases where the country noted two outbreaks of a highly contagious bird flu virus in the southern state of Kerala [2].

As per reports from the Indian Ministry of Agriculture, the virus killed about 15,000 infected ducks in Kottayam and another 500 in nearby Alappuzha. The report stated the animals died of an H5 strain of the flu virus but did not specify the exact variant.

Government and the Healthcare Ministry are collectively working towards controlling the situation, in the midst of other deadly infections such as Swine flu and COVID-19; Kerala government on Saturday ordered the poultry culling [3]. Recently on March 7, two avian influenza incidents were reported in South Kerala.

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What Is Bird Flu?

Avian influenza, a type of viral infection not only affects birds but also other animals and birds, however, most forms of the virus are restricted to birds [4]. H5N1 is the most common form of bird flu which is deadly to birds and easily affects human beings who come in contact with a carrier [5].

According to the World Health Organization, H5N1 has killed nearly 60 per cent of those infected [6]. The first outbreak of H5N1 bird flu was in December 2003. The virus passes easily between birds, nasal secretions, through their saliva, faeces, and feed [7].

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What Are The Symptoms Of Bird Flu?

An individual with an H5N1 infection will have the following signs and symptoms [8]:

  • Cough, usually dry
  • Sore throat
  • Hoarse voice
  • Fever (over 100.4°F or 38°C)
  • Muscle aches
  • Joint and bone ache
  • Headache
  • Shortness of breath (breathing difficulties)
  • Diarrhoea
  • Runny nose
  • Malaise (a general feeling of discomfort or illness)
  • Cold sweats and chills
  • Loss of appetite
  • Bleeding from the gums
  • Bloody sputum
  • Sleeping difficulties

The incubation period is from 2 to 8 days, and it can take up to 17 days [9]. Initial symptoms include a high fever (38°C) with lower respiratory tract symptoms, and in some rare cases upper respiratory tract symptoms.

Some individuals may pneumonia and breathing difficulties, which usually develops around 5 days after the first symptoms. This can lead to complications such as pneumonia, multiple organ failure, and death [10].

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What Causes Bird Flu?

Humans can become infected and ill after coming into contact with infected birds. Although H5N1 occurs naturally in wild waterfowl but spreads to domestic poultry such as chicken, ducks and geese easily [11]. The feet and bodies of animals can also carry the H5N1 virus.

The following can lead to one catching the strain of virus:

  • Attending markets selling live birds
  • Preparing infected poultry for cooking
  • Slaughtering or butchering infected poultry
  • Touching or breathing in faeces and other secretions of infected birds
  • Touching or defeathering infected birds

Note: Eating cooked poultry or eggs does not cause infection. However, you should cook poultry until the internal temperature is at least 74°C, and eggs until both the white and yolk are firm [12].

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What Are The Risk Factors For Bird Flu?

The H5N1 virus has the ability to survive for extended periods of time causing the affected birds to release the virus through faeces and saliva for a period as long as 10 days [13].

The following are bird flu risk factors [14]:

  • An individual working as a poultry farmer
  • An individual visiting affected areas
  • Exposure to infected birds
  • Eating undercooked poultry or eggs
  • Healthcare worker caring for infected patients
  • Household member of an infected person
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What Are The Complications Of Bird Flu?

People with bird flu may develop life-threatening complications such as [15]:

  • Pink eye (conjunctivitis)
  • Pneumonia
  • Kidney dysfunction
  • Respiratory failure
  • Heart problems
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How Is Bird Flu Diagnosed?

Laboratory tests: Samples of fluids from your nose or throat will be tested for the virus. These samples must be taken within the first few days after symptoms appear.

Imaging tests: X-rays will be taken to assess the condition of your lungs.

The CDC has approved a test called influenza A/H5 (Asian lineage) virus real-time RT-PCR primer and probe set which can help provide preliminary results in only four hours [16]. But due to the limited availability of the test, doctors prefer the following tests:

  • Auscultation (a test that detects abnormal breath sounds)
  • White blood cell differential
  • Nasopharyngeal culture
  • Chest X-ray

Note: Additional tests may be done to assess the functioning of your heart, kidneys, and liver.

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What Is The Treatment For Bird Flu?

According to the WHO, antiviral medications can help suppress viral replication and improve patients' health and can help prevent some cases from becoming fatal [17]. Also, different types of bird flu can cause different symptoms; as a result, treatments may vary.

In most cases, antiviral medications can reduce the severity of the disease. And, the medication must be taken within 48 hours after symptoms first appear [18]. You'll be placed in isolation to avoid spreading the virus to others.

In case of severe respiratory infections, your doctor may place you on a breathing machine.

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Can You Prevent Bird Flu?

It is impossible to prevent bird flu from spreading, but measures can be taken to spread awareness and also by monitoring bird migration patterns. Vaccinations are not available specifically for bird flu that is available to the public [19].

One can limit the onset and reduce the spread of bird flu by considering the following precautions [20]:

  • Wash hands regularly with warm water and soap.
  • While coughing, cough into an elbow or a tissue and carefully dispose of the tissue.
  • Those who are sick should stay away from public places and avoid contact with people.
  • Stay up-to-date especially with the seasonal flu and pneumococcal vaccines.
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On A Final Note…

Currently, the virus isn't known to spread via human-to-human contact. However, scientists see a possibility of the viral infection becoming a pandemic threat to humans. Maintain hygiene and follow the steps as directed by health experts.

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Frequently Asked Questions

Q. Is bird flu dangerous to humans?

A. H5N1 is a highly pathogenic avian influenza (HPAI) virus. It's deadly to most birds and is deadly to humans and to other mammals that catch the virus from birds. But unlike human flu bugs, H5N1 bird flu does not spread easily from person to person.

Q. How do you catch bird flu?

A. Most of the people who get bird flu have had close contact with infected birds or with surfaces that have been contaminated by the birds' saliva, mucous, or droppings. It is also possible to get it by breathing in droplets or dust that contain the virus. Rarely, the virus has spread from one person to another.

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Story first published: Thursday, March 19, 2020, 14:00 [IST]