Microbial Top Facts: Influenza H1N1

We are back with our microbial top facts blog series! Today, our microbiologists are taking a closer look at Influenza H1N1 flu, otherwise known as ‘Swine flu’.

Influenza H1N1 flu is a communicable viral disease caused by the Influenza A H1N1 virus strain. It got its name due to its common infections in pigs. The H1N1 Influenza A strain can cause infections in humans as well, especially people who work closely with pigs, although transmission from person to person can be inefficient. However, over the years the virus has been seen to evolve and readily change its genetic material (RNA) resulting in a more efficient transmission from person to person.

In 1918, the H1N1 influenza pandemic also known as the ‘Spanish Flu’ occurred due to rapid transmission from pigs to humans. As a result, 50 to 100 million deaths worldwide were attributed to the virus. In 2009, the mutant strain of H1N1 influenza virus spread again with high efficiency in transmission from a human to a human, with a CDC estimation of up to 60.8 million cases in the United States alone.

The 2009 H1N1 influenza pandemic was declared over by the World Health Organisation on August 10, 2010, but the swine flu virus remains and continues to be found around the globe as a seasonal virus causing cases of flu. Keep reading for facts about the Influenza virus A H1N1.

Where can we find Influenza H1N1

Despite being referred to as swine flu, the H1N1 flu virus is not caught by eating pork. Like other flu viruses, it is contracted from another person via droplets of mucus or saliva that contain the virus. The infected person breathes the droplets out and the other person breathes them in.

What makes it thrive

Flu viruses can mutate. The influenza virus A H1N1 genetic material changes readily which keeps the virus one step ahead of vaccine development. Vaccines are developed against known types of viruses but when the virus mutates into a completely new strain, a vaccine can become redundant. For example, the seasonal flu vaccine first issued in the autumn of 2014 was barely able to protect people from the main strain of flu circulating in the UK that winter, protecting only 3 out of every 100 vaccinated people from developing symptoms.

What can it cause?

The symptoms of flu caused by the H1N1 virus include a fever, body aches and chills, tiredness, headache and fatigue, diarrhoea, nausea and a runny nose. Infections can spread rapidly because the virus is highly contagious.

Swine flu, Avian flu – what’s the difference?

Avian flu does not easily infect humans because the virus has not mutated in a way that makes it transmissible by humans to other humans Swine flu seems to have made this step and can be transmitted readily from human to human.