(swine flu)

April 27, 2009
Swine flu is a respiratory disease of pigs first described in the 1930s and while historic transmissions to people have been "sporadic", the human infection rate is rising.

Before the current spate of cases, there were 12 known transmissions of swine flu to humans across the United States from 2005 to February this year.

This was up from just one person contracting swine flu "every one or two years" across the US up to 2005.

"Swine flu viruses do not normally infect humans, however, sporadic human infections with swine flu have occurred," says the United States' Centers for Disease Control and Prevention (CDC).

The cases commonly involved pig industry workers, the CDC says, or people who came into close contact with infected pigs at country fairs.

In pigs, swine flu symptoms can include a sudden onset of fever, coughing, sneezing and a discharge from the nose or eyes.

Outbreaks in herds tend to occur during the colder months, and vaccines are available to control its spread in pigs.

"In humans, the swine virus exhibits symptoms of regular human flu, including fever, cough, sore throat, body aches, headache, chills and fatigue," the CDC says.

"Some people have reported diarrhoea and vomiting."


Swine flu can also lead to severe infections because it is not recognised by the human immune system, and it is not likely to be stopped by drugs developed to combat human variants of the flu.

It can cause pneumonia or respiratory failure, particularly in people with underlying chronic medical conditions, and human deaths have been reported previously from swine flu cases.

An outbreak of swine flu at a US army base in New Jersey in 1976 resulted in four soldiers being struck down with pneumonia and one of them died before the virus disappeared.

Of the several strains of the swine flu known to be circulating in the world's pig populations, the one labelled H1N1 is the most common and it is a new variant of this strain which is thought responsible for the latest spate of cases.

The concern is this new strain has the ability to pass from person to person, though the CDC also says it has documented cases of human-to-human transmission of swine flu before.

In 1988, a healthy 32-year-old pregnant woman died from swine flu-related pneumonia two weeks after she visited a country fair pig exhibition in the US.

Follow-up studies indicated up to three health care workers who helped to care for the woman later developed a "mild influenza" linked to swine flu.

Aside from swine flu, pigs are also able to catch the flu from humans and birds and it is this intermingling of different viruses from various species which leads to the emergence of new viruses.

The different viruses swap their genes when inside infected pigs and a new mix of swine, human or avian influenza can then emerge.

The CDC warns that a new virulent strain of swine flu, capable of being transmitted from person to person, would be passed on in much the same way as human flu.

"... through coughing or sneezing of people infected with the influenza virus," it says.

"People may become infected by touching something with flu viruses on it and then touching their mouth or nose."

You cannot get swine flu from eating pork as the virus is killed through the cooking process.

AAP
إسلام صلاح(المزارى)