H1n1 (swine) Influenza Guide: swine flu

Definition
Swine influenza is flu virus usually found in pigs. The virus occasionally changes (mutates) and becomes infectious in humans. When this happens, the disease becomes a concern to humans, who have little or no immunity against it. This means the virus has the potential to spread quickly around the world. It also may be more difficult to treat than the usual, seasonal human flu viruses.

Causes, Incidence, And Risk Factors
In the spring of 2009, cases of human infection with H1N1 flu were confirmed in Mexico, the United States, and many countries around the world. The H1N1 flu virus is contagious and can spread from human to human. At this time, it is unknown how easily it can spread between people. It is known that flu viruses can spread from pigs to people, and from people to pigs. However, you CANNOT get H1N1 flu virus from eating pork.
Human-to-human infection with the H1N1 flu virus likely occurs the same way as seasonal flu, when an infected person coughs or sneezes into air that others breathe in. People may also get infected by touching something with the virus on it, such as a door knob or counter, and then touching their mouth or nose.

Symptoms
Symptoms of H1N1 flu infection in humans are similar to classic flu-like symptoms, which might include:
* Fever above 100.4 °F
* Cough
* Sore throat
* Headache
* Chills
* Muscle aches
* Diarrhea
* Vomiting
Signs And Tests
If you think you have been exposed to H1N1 influenza, call your health care provider before your visit. This will give the staff a chance to take proper precautions to protect them and other patients during your office visit. If the H1N1 flu becomes widespread, there will be little need to continue testing people, so your health care provider may decide not to test for the flu virus.
Your doctor may perform the following physical exam:
* Auscultation (to detect abnormal breath sounds)
* Chest x-ray
Your doctor can test for the H1N1 flu virus using a nasopharyngeal swab (a swab of the back of the inside of your nose), or grow it in a culture. However, this will likely happen only if:
* You are at high risk for flu complications.
* You are very sick.
Treatment
Most people who get H1N1 flu will likely recover without needing medical care. Doctors, however, can prescribe antiviral drugs to treat people who become very sick with the flu or are at high risk for flu complications. The CDC currently identifies the following people as high risk:
* Children younger than 5 years old, especially those younger than age 2
* Adults 65 years of age and older
* People with:
o Chronic lung (including asthma) or heart conditions (except hypertension)
o Kidney, liver, neurologic, and neuromuscular conditions
o Blood disorders (including sickle cell disease)
o Diabetes and other metabolic disorders
o An immune system that does not work well, such as AIDS patients or cancer patients receiving chemotherapy

Other high risk people include:
* Pregnant women
* Anyone younger than 19 years of age receiving long-term aspirin therapy
* Residents of nursing homes and other chronic-care facilities

Timeline: Swine flu

A chronology of the H1N1 outbreak.

A new strain of swine flu - influenza A (H1N1) - is spreading around the globe. This timeline will be continually updated with key dates, drawing on authoritative information from the World Health Organization (WHO), the US Centers for Disease Control and Prevention (CDC) and other sources. For more on the situation see the Nature News swine flu special, and read updates on The Great Beyond blog.

3 August 2009 : India confirms first death from H1N1, the victim being a 14-year old girl in the city of Pune.

29 July 2009 : Researchers from the US Centers for Disease Control and Prevention warn that pregnant women "might be at increased risk for complications from pandemic H1N1" in a research paper in The Lancet (more on this story).

The UK moves its swine flu response from 'containment' to 'treatment'. "Our national focus should be on treating the increasing numbers affected by swine flu," says health minister Andy Burnham. In the US there are or have been cases in all 50 states, including 17 deaths, according to the CDC. MedImmune, a biotechnology firm in Gaithersburg, Maryland, wins a $90 million contract from the federal government to begin developing a live attenuated vaccine for H1N1. "This virus may have given us a grace period, but we do not know how long this grace period will last," said Margaret Chan, WHO director-general. "No one can say whether this is just the calm before the storm."

Mexico has reported 48 deaths and the United States three. Worldwide, 30 countries have officially reported 4694 cases. A modeling study in Science suggests that the virus spreads at a rate comparable to that of previous influenza pandemics. The latest WHO figures say the virus has now spread to 21 countries. Mexico has reported 590 cases and 25 deaths while the United States has reported 286 cases and one death.

However, the Texas Department of State Health Services has confirmed a second person has died in the United States. The DSHS says a woman with "chronic underlying health conditions" died earlier this week.

The following countries have reported cases but no deaths: Austria, Canada, China (Hong Kong Special Administrative Region), Costa Rica, Colombia, Denmark, El Salvador, France, Germany, Ireland, Israel, Italy, Netherlands, New Zealand, Portugal, Republic of Korea, Spain, Switzerland and the United Kingdom.

Canadian authorities announce that H1N1 has been detected in a swine herd in Alberta. The pigs likely caught the virus from a Canadian who had recently visited Mexico, making this the first known case of human-to-animal transmission.

The WHO raises pandemic alert level to 4 having confirmed human-to-human transmission able to cause 'community-level outbreaks'. "Phase 4 indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion," says the organisation.