Bird Flu: Symptoms, Causes And Cure
Bird flu has high public health concerns. Humans get infections from diseased birds with certain conditions. So, know the symptoms, causes, and cure for this disease.
Written by Dr Sonia Bhatt
Last updated on 3rd Jul, 2025
Bird flu, or avian influenza, is a viral disease that primarily affects birds, and it has the potential to infect human beings in certain conditions. Primarily found in wild water birds, this virus has been responsible for various outbreaks across the world, affecting domestic poultry and human lives. With strains like H5N1 and H7N9 posing severe health risks, bird flu has negatively impacted public health and global economies. This disease was first identified in the late 19th century in Europe, and later, multiple variants and mutations were uncovered across the world. The first human case of bird flu was observed in Southern China in 1996. Since then, several cases have been found across the world.
Understanding Bird Flu Transmission
Generally, bird flu spreads rapidly among birds, making it a highly contagious disease. Although the cases of human contamination have been relatively lower, it is a possibility. In most cases, human beings in contact with infected birds or animals or in a contaminated environment suffer from this disease.
Transmission to humans typically happens when the virus enters the body through the nose, mouth, eyes, or respiratory system. This can occur through inhaling airborne virus particles, particularly in areas with infected birds, or by touching virus-contaminated surfaces and subsequently touching the face. Such modes of transmission emphasise the importance of maintaining strict hygiene and protective measures to minimise exposure risks.
There are different subtypes of avian influenza. The most common subtypes that caused infection among people in the past are influenza A(H5N1) and influenza A(H7N9). Also, several cases of influenza A(H5) have been found in the USA. Also, other subtypes such as A(H5N6), A(H3N8), A(H9N2), A(H10N3), A(H7N4) of avian influenza viruses have been found too.
Additionally, the risk factors for transmission include:
The bird flu viruses survive for a long duration.
Infected birds can spread viruses with them for up to 10 days.
Symptoms of Bird Flu in Humans
During the early stage of the disease, people suffer from mild symptoms. But the situation became worse without timely treatment. The early symptoms include:
Redness and irritation (conjunctivitis) in the eyes
Cough
Headaches
Mild fever
Sore throat
Muscle or body aches
Runny or stuffy nose
Severe symptoms and complications include:
Respiratory failure
Acute respiratory distress syndrome
Pneumonia
Multi-organ failure
Inflammation of the brain (meningoencephalitis)
Sepsis, septic shock
Causes and Risk Factors
Bird flu primarily originates from avian hosts like ducks and geese, acting as natural sources of this virus. Moreover, these birds usually carry this virus without showing any symptoms, spreading to other living beings of the same category. Environmental and occupational hazards also play a significant role in the transmission of bird flu. Individuals working in poultry farms, live bird markets, or slaughterhouses remain at a higher risk due to their frequent and close interaction with birds. Additionally, contaminated water, soil, and surfaces in areas with infected birds increase the risk of spreading this virus.
Diagnosis of Bird Flu
The Centres for Disease Control and Prevention (CDC) approved a diagnostic test for bird flu. The test is known as the influenza A/H5 virus real-time RT-PCR primer and probe set. However, the test only provides preliminary results. Thus, the doctor may recommend other tests to identify the presence of bird flu in individuals. The tests include chest X-ray, white blood cell differential, nasopharyngeal culture, and auscultation.
Additionally, doctors may prescribe tests to assess liver, heart, and kidney functionalities.
Treatment Options for Bird Flu
Numerous symptoms of bird flu include varying treatments based on the symptoms. For instance, in the case of mild symptoms, treatment continues with antiviral medications such as zanamivir (Relenza) or oseltamivir (Tamiflu). These medications protect the patient from developing severe symptoms.
On the other hand, the symptomatic treatment of bird flu includes treating high fever with relevant medications. The doctors also ask the patients to focus on hydration and consume enough liquid in case of high fever and diarrhoea. Additionally, the doctors can also suggest oxygen therapy for patients experiencing breathing difficulties or respiratory distress.
Preventive Measures
There are certain guidelines and vaccination procedures to prevent the disease from being spread.
The health authorities are considering vaccination against seasonal influenza as research on the avian influenza virus is still ongoing. Though the seasonal influenza vaccine doesn't completely protect humans against the bird flu virus, it can help eliminate the co-infection of seasonal and avian influenza.
Also, individuals must obey the protective measurement guidance provided by the World Health Organisation (WHO).
Global Response and Public Health Strategies
Individuals should follow these guidelines by WHO to protect themselves:
Personal Protective Equipment (PPE) is mandatory. PPE includes an apron or surgical gown with long sleeves, rubber gloves, goggles, well-fitted surgical masks or N95 respirator masks, and rubber or polyurethane boots.
Be aware of the early symptoms of bird flu.
A regular health checkup is mandatory to evaluate any symptoms during regular exposure to suspected birds or animals, and it should be continued after 14 days of the last exposure.
The suspected person should stay in isolation.
If required, serum and epidemiological data should be collected from people exposed to the birds/animals for laboratory testing.
WHO monitors avian and other influenza viruses closely through its Global Influenza Surveillance and Response System (GISRS). WHO conducts this surveillance with the World Organisation for Animal Health (WOAH) and the Food and Agriculture Organisation of the United Nations (FAO) and their mission is to assess the risks and responses related to zoonotic influenza (a disease caused by animal influenza viruses that can infect humans).
Research and Advances
As there is no specific vaccination available for bird flu, healthcare providers recommend seasonal influenza vaccines for bird flu patients. However, different pharmaceutical companies and research institutes across the globe are trying to develop a feasible vaccine for bird flu.
In 2024, a new project was initiated to develop an advanced mRNA (messenger RNA) vaccine against the human avian influenza (H5N1) virus. The project is known as the mRNA Technology Transfer Program. WHO and the Medicines Patent Pool (MPP) have jointly developed this project. This project aims to help low- and middle-income countries leverage their research and development efforts. Also, under this project, an Argentinian manufacturer named Sinergium Biotech developed H5N1 vaccines to confirm proof-of-concept for the preclinical models. The researchers and scientists are optimistic about the project. They are looking to produce a high-quality bird flu vaccine through this initiative in future.
Conclusion
Bird flu poses significant concerns for public health and can also impact other mammals. Moreover, the unpredictable nature of the virus makes it a serious threat, often leading to substantial economic losses. In response, ongoing vigilance and research have been instrumental in uncovering crucial details of its transmission and control and researchers are actively working to develop effective vaccines for bird flu. Meanwhile, public awareness remains crucial as a clear understanding would prepare people to minimise its spread and reduce the risk of infection.
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Dr. Lakshmi Sindhura Kakani
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Apollo Clinic Bellandur, Bangalore
