H9N2 avian influenza virus

H9N2 avian influenza virus

H9N2 is a subtype of the influenza A virus that primarily affects birds, including poultry like chickens. It’s known to cause respiratory illness in birds and has been found in various avian species globally.

Although it primarily circulates among birds, there have been some cases of H9N2 infections in humans. However, these cases are relatively rare. When transmission occurs to humans, it typically results in mild respiratory symptoms. There hasn’t been widespread human-to-human transmission reported for this subtype, which is good news.

Research on H9N2 continues as scientists monitor its potential to mutate or reassort with other influenza viruses. Potentially leading to strains that could pose greater risks to human health. It’s one of several strains of avian influenza that health organizations keep an eye on due to its potential for causing illness in both birds and humans. 

WHO statement on reported clusters of respiratory illness in children in northern China

At a press conference on 13 November 2023, Chinese authorities from the National Health Commission reported an increase in incidence of respiratory diseases in China. Chinese authorities attributed this increase to the lifting of COVID-19 restrictions and the circulation of known pathogens such as influenza, mycoplasma pneumoniae (a common bacterial infection which typically affects younger children), respiratory syncytial virus (RSV), and SARS-CoV-2 (the virus that causes COVID-19).

On 21 November, media reported clusters of undiagnosed pneumonia in children in northern China. It is unclear if these are associated with the overall increase in respiratory infections previously reported by Chinese authorities, or separate events.

On 22 November, WHO requested additional epidemiologic and clinical information, as well as laboratory results from these reported clusters among children, through the International Health Regulations mechanism. We have also requested further information about recent trends in the circulation of known pathogens including influenza, SARS-CoV-2, RSV and mycoplasma pneumoniae, and the current burden on health care systems. WHO is also in contact with clinicians and scientists through our existing technical partnerships and networks in China.

While WHO seeks this additional information, we recommend that people in China follow measures to reduce the risk of respiratory illness, which include recommended vaccination; keeping distance from people who are ill; staying home when ill; getting tested and medical care as needed; wearing masks as appropriate; ensuring good ventilation; and regular hand-washing.

What are the symptoms of H9N2?

The symptoms of H9N2 influenza in humans are similar to those of other types of influenza and often include:

1. Fever
2. Cough
3. Sore throat
4. Muscle aches
5. Fatigue
6. Difficulty breathing in severe cases

These symptoms are typical of respiratory infections, and while H9N2 infections in humans have generally been mild, they can vary from person to person. Some individuals may experience more severe symptoms or complications, especially those with weakened immune systems or underlying health conditions. If anyone suspect then he have been exposed to H9N2 or have symptoms consistent with influenza, then need to  seek medical attention for proper evaluation and care.

What precautions can prevent H9N2?

Preventive measures to reduce the risk of H9N2 influenza, or any influenza strain for that matter, involve basic hygiene practices and some specific precautions:

Good Hygiene: Regularly wash your hands with soap and water for at least 20 seconds, especially after coughing, sneezing, or being in public places. If soap and water aren’t available, use alcohol-based hand sanitizers.

Avoid Close Contact: Try to avoid close contact with individuals who are sick. If you’re feeling unwell, it’s also considerate to limit contact with others to prevent potential transmission.

Cover Mouth and Nose: Use tissues or your elbow to cover your mouth and nose when coughing or sneezing. Dispose of tissues properly and wash your hands immediately.

Use Masks: Wearing masks, especially in crowded or high-risk areas, can help reduce the spread of respiratory droplets.

Vaccination: While there might not be a specific vaccine for H9N2, getting vaccinated against seasonal influenza can reduce the risk of getting sick from various strains of influenza and potentially lessen the severity of symptoms if infected.

Avoid Exposure to Birds: If you live in or visit areas with poultry or birds, take precautions to avoid direct contact with them or their droppings, as these are common carriers of avian influenza viruses.

Food Safety: Ensure that poultry and eggs are properly cooked before consumption to kill any potential viruses.

Remember, these practices not only help prevent H9N2 but also reduce the risk of contracting other contagious diseases and viruses.

Types of influenza

There are four main types of influenza viruses: A, B, C, and D. They belong to the Orthomyxoviridae family.

Influenza A: This type is the most common and versatile. It infects humans, birds, and some other animals. Influenza A viruses are further classified based on the surface proteins they carry: hemagglutinin (H) and neuraminidase (N). There are many subtypes of influenza A viruses, such as H1N1, H3N2, etc. These viruses can cause moderate to severe illness in humans and are responsible for flu pandemics.

Influenza B: This type mostly infects humans and is less variable than influenza A. It causes seasonal outbreaks and can be severe but generally does not lead to pandemics. The virus are not classified into subtypes but can still cause significant illness.

Influenza C: This type also infects humans but typically causes milder respiratory symptoms. This C viruses do not cause regular seasonal flu epidemics and are less common than types A and B.

Influenza D: This type primarily affects cattle and is not known to infect humans easily. It’s more recently discovered compared to the other types and generally causes mild illness in cattle.

Influenza viruses, especially types A and B, are responsible for seasonal outbreaks and can lead to widespread illness. They mutate frequently, which is why new flu vaccines are developed each year to match the most prevalent strains expected to circulate during the upcoming flu season. These vaccines aim to provide protection against the specific strains of influenza viruses that are anticipated to be most common during that year.

Is there any vaccine for h9n2?

As of my last update in January 2022, there isn’t a specific vaccine designed solely for H9N2 influenza in humans. Most vaccines target the prevalent strains of influenza A (like H1N1 and H3N2) and influenza B viruses. These vaccines are formulated based on predictions about the strains likely to circulate in a given flu season.

Research on H9N2 vaccines has been ongoing…

but no widely distributed or approved vaccine specifically targeting H9N2 in humans existed at that time. However, scientists continually monitor and study these strains to understand their behavior and develop potential vaccines or improve existing ones to offer broader protection against various influenza strains, including H9N2, should the need arise in the future.

Is it dangerous for human body?

H9N2 influenza viruses have primarily caused mild respiratory illness in humans when infections occur. However, their potential to cause severe illness or complications in humans is a concern, especially for individuals with weakened immune systems or underlying health conditions.

While human cases of H9N2 influenza have generally been mild, the main concern with influenza viruses, including H9N2, is their ability to mutate and potentially reassort with other influenza viruses. This could lead to the emergence of new strains that might pose a greater risk to human health.

Regular surveillance and research on influenza viruses like H9N2 are essential to understand their behavior and potential threat to human health. Taking precautions to prevent infection, such as practicing good hygiene and getting vaccinated against seasonal influenza, remains important to reduce the risk of illness from various influenza strains, including H9N2.

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