| August 17th, 2010 | By: Bijoy Bora | Category: Health/Lifestyle

What is Swine flu (H1N1)?Swine flu is a respiratory disease which infects pigs. Caused by influenza type a virus, there are regular outbreaks among herds of pigs, where the disease causes high levels of illness but is rarely fatal.

It tends to spread in autumn and winter but can circulate all year round.

There are many different types of swine flu and like human flu, the infection is constantly changing.

Swine flu does not normally infect humans, although sporadic cases do occur usually in people who have had close contact with pigs.There have also been rare documented cases of humans passing the infection to other humans.

Human to human transmission of swine flu thought to spread in the same way as seasonal flu – through coughing and sneezing.

The outbreak in Mexico seems to involve a new type of swine flu that contains DNA that is typically found in avian and human viruses.the World Health Organization has confirmed at least some of the cases are caused by this new strain of H1N1.

What are the symptoms of swine flu (H1N1)?Symptoms of swine flu are similar to most influenza infections: fever (100F or greater), cough, nasal secretions, fatigue, and headache, with fatigue being reported in most infected individuals. some patients also get nausea, vomiting, and diarrhea. In Mexico, many of the patients are young adults, which made some investigators speculate that a strong immune response may cause some collateral tissue damage.

Some patients develop severe respiratory symptoms and need respiratory support (such as a ventilator to breathe for the patient). Patients can get pneumonia (bacterial secondary infection) if the viral infection persists, and some can develop seizures. Death often occurs from secondary bacterial infection of the lungs; appropriate antibiotics need to be used in these patients. the usual mortality (death) rate for typical influenza a is about 0.1%, while the 1918 “Spanish flu” epidemic had an estimated mortality rate ranging from 2%-20%. Swine flu in Mexico (as of April 2009) has had about 160 deaths and about 2,500 confirmed cases, which would correspond to a mortality rate of about 6%, but these initial data have been revised and the mortality rate currently in Mexico is estimated to be much lower.

How is swine flu (H1N1) diagnosed?Swine flu is presumptively diagnosed clinically by the patient’s history of association with people known to have the disease and their symptoms listed above. Usually, a quick test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza a or B virus.

Most of the tests can distinguish between a and B types. the test can be negative (no flu infection) or positive for type a and B. If the test is positive for type B, the flu is not likely to be swine flu (H1N1). If it is positive for type a, the person could have a conventional flu strain or swine flu (H1N1).

However, the accuracy of these tests has been challenged, and the U.S. Centers for Disease Control and Prevention (CDC) has not completed their comparative studies of these tests. However, a new test developed by the CDC and a commercial company reportedly can detect H1N1 reliably in about one hour; as of October 2009, the test is only available to the military.

What treatment is available for swine flu (H1N1)?The best treatment for influenza infections in humans is prevention by vaccination. Work by several laboratories has recently produced vaccines. the first vaccine released in early October 2009 was a nasal spray vaccine. It is approved for use in healthy individuals ages 2 through 49.

This vaccine consists of a live attenuated H1N1 virus and should not be used in anyone who is pregnant or immunocompromised. the injectable vaccine, made from killed H1N1, became available in the second week of October. This vaccine is approved for use in ages 6 months to the elderly, including pregnant females. Both of these vaccines have been approved by the CDC only after they had conducted clinical trials to prove that the vaccines were safe and effective. However, caregivers should be aware of the vaccine guidelines that come with the vaccines, as occasionally, the guidelines change. please see the sections below titled “Can novel H1N1 swine flu be prevented with a vaccine?” and the timeline update for the current information on the vaccines.

Two antiviral agents have been reported to help prevent or reduce the effects of swine flu. they are zanamivir (Relenza) and oseltamivir (Tamiflu), both of which are also used to prevent or reduce influenza a and B symptoms. These drugs should not be used indiscriminately, because viral resistance to them can and has occurred. Also, they are not recommended if the flu symptoms already have been present for 48 hours or more, although hospitalized patients may still be treated past the 48-hour guideline. Severe infections in some patients may require additional supportive measures such as ventilation support and treatment of other infections like pneumonia that can occur in patients with a severe flu infection. the CDC has suggested in their interim guidelines that pregnant females can be treated with the two antiviral agents.