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What is the Hong Kong Flu?

Geisha A. Legazpi
Geisha A. Legazpi

Hong Kong flu is a type of seasonal flu that is caused by a subtype of the influenza virus called H3N2. The H3N2 strain is able to infect birds and mammals, such as humans. It causes symptoms similar to that of a common cold, so people often disregard it until their conditions become worse. Hong Kong flu, however, can cause serious diseases and even lead to death if not addressed properly.

Like any other influenza virus, the H3N2 subtype has two distinct proteins on its surface. These proteins are called hemagglutinin, represented by the letter H, and neuraminidase, represented by the letter N. It is believed to have formed because of an antigenic shift, or a gene reassortment of different existing flu strains. In particular, it has been shown that the H3N2 subtype has genes from existing bird, pig, and human influenza A strains.

The Hong Kong flu can cause a sore throat.
The Hong Kong flu can cause a sore throat.

The H3N2 influenza A virus can cause Hong Kong Flu when it is transmitted from a person who has the virus to a person who is not immune to the virus. Transmission can occur through different routes. The most common routes are through direct contact and respiratory droplets. This means that simply being in the same room with an infected person or touching his or her things could result in the transmission of Hong Kong flu.

Symptoms of the Hong Kong flu typically last for 4-5 days, and can include fever, chills and fatigue.
Symptoms of the Hong Kong flu typically last for 4-5 days, and can include fever, chills and fatigue.

It is also said that the H3N2 virus can be transmitted through the gastrointestinal; hematogenous, or blood; and sexual routes. A person can get infected by eating contaminated food, undergoing a transfusion with contaminated blood, or having sexual contact with an infected person. Fetal transmission may also occur when a pregnant woman gets the virus.

Cases of Hong Kong flu are often initially mistaken for a severe cold.
Cases of Hong Kong flu are often initially mistaken for a severe cold.

Symptoms include runny nose, nasal congestion, cough, and sore throat. Headache, fever, joint and muscle aches, chills, and fatigue may present as well. Symptoms typically last about 4 to 5 days. A patient might feel so sick that he loses his appetite and feels weak. If not properly addressed, the disease can lead to pneumonia and asthma or chronic obstructive pulmonary disease (COPD) exacerbation. In children, it can result in a high fever and seizures. It also can lead to fetal developmental problems during pregnancy.

Taking aspirin is advisable when recovering from the Hong Kong flu.
Taking aspirin is advisable when recovering from the Hong Kong flu.

Bed rest aids in recovery and prevents further transmission of the virus. To relieve fever and pain symptoms, aspirin or paracetamol may be taken. An adequate fluid intake is essential to prevent dehydration. The doctor may give antiviral drugs, such as oseltamivir or zanamivir, if deemed appropriate.

The first world pandemic occurred between 1968 and 1969 and was believed to have caused a million deaths. This disease still holds a pandemic status because it affects multiple countries annually. The World Health Organization (WHO) considers it as a category 2 flu pandemic because it only causes a 0.1- to 0.5-percent case fatality rate. This means that for every thousand people affected by the flu, one to five die from the infection. Therefore, compared to other influenza pandemics, such as severe acute respiratory syndrome (SARS), the Hong Kong flu pandemic is considered mild.

Discussion Comments

ddljohn

@serenesurface-- I think that if we think like that, we will become paranoid. The only thing we can do is see a doctor when we have flu symptoms. With most of these flu strains, they aren't dangerous as long as they're diagnosed quickly and treated. It's a good idea to also mention any recent visits to Asia or contact with birds or other animals to the doctor. Most people do get over flu just fine without complications.

serenesurface

@fify-- As of 2014, the Hong Kong flu doesn't seem to be a major concern. It did cause many deaths during the first emergence, but it is rarely seen these days. So it's not really an issue for you.

Keep in mind though, that it's just one variant of Avian flu and there are new kinds emerging all the time. The recent mutation appears to be the H7N9 flu. I wouldn't be surprised if a new variation came about next year.

Avian flu is a mutation of H1N1 and it can affect different animals and humans. So it doesn't mater that H3N2 isn't around much right now. There are plenty of other mutations occurring and creating risk for humans all the time.

fify

I am thinking of taking a job offer in Hong Kong for one year. Do I need to be worried about Hong Kong flu? It's mostly a thing of the past right?

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    • The Hong Kong flu can cause a sore throat.
      By: absolutimages
      The Hong Kong flu can cause a sore throat.
    • Symptoms of the Hong Kong flu typically last for 4-5 days, and can include fever, chills and fatigue.
      By: Subbotina Anna
      Symptoms of the Hong Kong flu typically last for 4-5 days, and can include fever, chills and fatigue.
    • Cases of Hong Kong flu are often initially mistaken for a severe cold.
      By: emde71
      Cases of Hong Kong flu are often initially mistaken for a severe cold.
    • Taking aspirin is advisable when recovering from the Hong Kong flu.
      By: areeya_ann
      Taking aspirin is advisable when recovering from the Hong Kong flu.
    • The Hong Kong flu can result in high fever and seizures in children.
      By: Zsolt Biczó
      The Hong Kong flu can result in high fever and seizures in children.