Swine influenza, "swine flue", or "swine flu" refers to influenza cases that are caused by Orthomyxoviruses endemic to pig populations. Swine flu infects people every year and is found typically in people who have been in contact with pigs, although there have been cases of person-to-person transmission.
2009 Swine Flu Outbreak
The 2009 Swine Flu outbreak is a new strain of influenza, which appears to be human flu (subtype H1N1) combined with two strains of swine flu and a strain of avian flu.
In April both the WHO and CDC expressed serious concerns about this new strain, because once it made the jump from pigs to people, it seemed to transmit from human to human, has had a relatively high mortality rate in Mexico, and because it has the potential to become a flu pandemic. Because we have learned a great deal about epidemiology and public health since the last great epidemic (the "Spanish flu" of 1918), international health bodies are better prepared for such a pandemic and may be able to prevent it from becoming widespread if it turns out to be a strain as dangerous as the 1918 virus. It may not -- a 1976 swine flu outbreak in humans prompted widespread vaccinations but only took one life.[1]
Several people in Mexico and the United States have become infected with this new strain, with unconfirmed cases in Canada, New Zealand, Spain, France, and Colombia. It has caused at least 20 confirmed deaths in Mexico. It's not clear why there are more deaths in Mexico than in other areas, as there are multiple variables, such as a stronger strain of the virus or more exposure to it.[2] No definite conclusion can be reached, however the CDC reported today that swine flu viruses in the US and Mexico match.[3]
Symptoms
- Adapted from: the CDC
The symptoms of swine flu in people are expected to be similar to the symptoms of regular human seasonal influenza and include fever, lethargy, lack of appetite and coughing. Some people with swine flu also have reported runny nose, sore throat, nausea, vomiting and diarrhea.
Transmission
Swine Flu viruses can be directly transmitted from pigs to people, and from people to pigs. Human infection is most likely to occur when people are in close proximity to infected pigs. Human-to-human transmission of swine flu can also occur, thought to be in the same way as seasonal flu occurs in humans. This would be mainly through the coughs or sneezes of infected people. People may become infected by touching something with flu viruses on it, and then touching their mouth or nose.
You can not get swine flu from eating pork. Cooking destroys the influenza virus. The name of "swine flu" does not refer to how you get it, but where it came from.
The exchange of proteins among flu viruses from humans, birds, and pigs is very common, and happens every year (and has nothing to do with genetic engineering). However, these combinations are usually only transmitted across the species barrier, so the number of people at risk is limited to those who work directly with pigs or poultry.
Prevention
Washing your hands regularly, preferably with an alcohol-based hand disinfectant, will significantly reduce the risk of contamination. If you are in a high-risk area, you should avoid directly touching well-touched surfaces (such as door handles). Surgical masks can also reduce the risk of contaminants reaching the mouth or nose, however these need to be well-fitting to the skin to give maximum protection, stopping any contaminants floating around the edges.
- See more at How can I protect my family
Diagnosis
If you are concerned that you (or someone you) know may have flu, you should seek the advice of a medical professional. This gives the best chance of accurate diagnosis and early treatment.
To diagnose swine influenza A infection, a respiratory specimen (mucus/saliva) would generally need to be collected within the first 4 to 5 days of illness. This is when an infected person is most likely to be infectious. However, some persons, especially children, may shed virus for 10 days or longer. Identification as a swine flu influenza A virus requires sending the specimen for laboratory testing, such as to CDC.
Mutation
The influenza virus can be carried by migratory birds, who are not usually affected. The bird droppings can infect pigs, where the virus may mutate. New strains may be able to infect humans.