The disease is spread among pigs by direct and indirect contact, aerosols, and from pigs that are infected but do not have symptoms. In many parts of the world, pigs are vaccinated against swine flu.
Most commonly, swine flu is of the H1N1 influenza subtype. However, swine flu viruses can sometimes come from other subtypes, such as H1N2, H3N1, and H3N2.
The 2009 outbreak of swine flu that infected humans was of the H1N1 subtype. It is important to note that, although it developed in swine, the 2009 pandemic virus was not completely derived from swine. The virus contains a combination of flu genes from bird, swine, and human flu types.
Here are some key points about swine flu.
- Swine flu was normally of the H1N1 influenza subtype. However, since 2017, the H3N2 subtype has become the dominant strain.
- The most common way for a human to catch swine flu is through contact with a pig.
- There is currently a vaccine for swine flu that is included with the standard seasonal flu shots.
- Symptoms of swine flu include coughs, chills, and aches, similar to seasonal flu.
Swine flu is spread to humans primarily through contact with infected pigs.
The symptoms of swine flu in humans are quite similar to those of regular flu, and include:
Less commonly, a person with swine flu may experience vomiting and diarrhea
Symptoms can be managed with similar treatments to regular flu. However, a doctor should examine the patient for confirmation of swine flu and advise how to relief individual symptoms.
A vaccine has been produced to protect humans against the H1N1 strain of swine flu. This was introduced following a pandemic of swine flu in 2009 and 2010.
The status of swine flu has changed from a pandemic to a seasonal type of human influenza. The specialized vaccine has now been replaced by more general seasonal flu shots.
People who are over 10 years old only require one shot of the vaccine. The U.S. Food and Drug Administration (FDA) recommends two shots for children under this age, to be taken four weeks apart.
People with an egg allergy and children with severe asthma are at risk of an adverse reaction to this vaccine and should discuss the shot with a healthcare professional. There are special regimens designed to help the bodies of people who experience these reactions accept the vaccine.
There are some drugs available that can effectively treat swine flu.
The two main treatments are adamantanes, including amantadine and rimantadine, and medications that inhibit the influenza neuraminidase protein, such as oseltamivir and zanamivir.
However, most people with swine influenza recover completely without the need for medical attention.
There are only a few causes of swine flu in humans. They are:
Contact with infected pigs: This is the most common way of catching swine flu. Any contact with infected pigs makes transmission more likely.
Contact with infected humans: This is a much less common way of catching swine flu, but is a risk, especially for those in close contact with an infected person.
In cases where humans have infected other humans, close contact was necessary with the infected person, and it nearly always occurred in closed groups of people.
Some people are more at risk of catching swine flu than others; including:
- people aged over 65 years
- children under 5 years
- people with chronic diseases
- pregnant women
- teenagers receiving long-term aspirin therapy
- anyone with a compromised immune system
Swine flu is mostly diagnosed through noting the symptoms.
There is also a quick test called the rapid influenza diagnostic test that can help identify swine flu. However, these vary in effectiveness and may show a negative result even though influenza is present. More accurate tests are available in more specialized laboratories.
However, in a similar way to seasonal flu, symptoms are often mild and self-resolve. Most people do not receive a test for swine flu as treatment would be the same, regardless of the outcome.
If symptoms are mild, it is extremely unlikely that any connection to swine influenza is found, even if the virus is there.
As there is no known single cure, steps can be taken at home to prevent swine flu and reduce symptoms if a person does contract the virus.
- washing hands regularly with soap
- getting plenty of sleep
- exercising often
- managing stress
- drinking liquids
- eating a balanced diet
- refraining from touching surfaces that may have the virus
Do not get close to people who are sick. Be sure to stay away from crowds if there is a swine flu outbreak in your area.
How to reduce the spread of infection?
If a person is infected, it is important they follow these rules to prevent any further spread:
- Limit contact with other people.
- Do not go to work or school.
- When coughing or sneezing cover the mouth with a tissue. If there is no tissue available, cover the mouth and nose.
- Put used tissues in a trash can.
- Wash the hands and face regularly.
- Keep all surfaces that are touched clean.
- Follow all doctors' instructions.
It is still perfectly safe to eat pork products, so long as they are cooked properly.
Viruses from pigs do occasionally cause outbreaks of human infection.
Because swine flu symptoms are similar to those of seasonal flu, swine flu in humans is often not detected. If it is found, it is normally during seasonal influenza surveillance.
Examples of swine flu infecting humans
Since the World Health Organization's (WHO's) implementation of IHR (2005) in 2007, they have been notified of swine influenza cases from the United States and Spain. In March to April 2009, human cases of influenza A swine fever (H1N1) were first reported in California and Texas.
Other states also reported cases later on. A significant number of human cases during the same period were also reported in Mexico - starting just in Mexico City, but then throughout various parts of the country.
More cases are being reported in Canada, Europe, and New Zealand, mainly from people who have been in Mexico.
Can I eat pork meat and pork products?
If pork meat and pork food products have been handled properly, transmission of swine influenza to humans is not possible. Cooking pork meats to a temperature of 160°F (70°C) kills the virus.
Pork meat and pork food products are safe to eat.
Where have pigs been infected with swine flu?
As swine influenza infection among pigs is not an internationally notifiable disease, it is not completely clear. Swine influenza infection among pigs is known to be endemic to the U.S.
Outbreaks have also occurred in other parts of North America, South American, Europe, Africa, China, Japan, and other parts of Asia.
Is there the risk of another pandemic?
People who are not in close contact with pigs generally have no immunity to the swine influenza viruses. They are less likely to be able to prevent a viral infection. If the virus infects enough people in a given area, the risk of an influenza pandemic is significantly greater.
It is very hard to predict what impact another swine flu pandemic would have on the global human population. This would depend on how aggressive the virus is, the existing immunity among humans, the strain behind the pandemic, and a number of other factors.
Will current vaccines work against swine flu?
Swine flu is now included in the seasonal flu shots.
Influenza viruses adapt and change all the time. The WHO says it needs access to as many viruses as possible so that it can isolate the most appropriate candidate for a vaccine.
Current vaccines are effective against many strains of swine flu.