H1N1 flu is a new influenza virus causing illness in people. It has two genes from flu viruses that normally circulate in pigs in Europe and Asia, plus avian genes and human genes. Scientists call this a “quadruple reassortant” virus.

H1N1 flu is contagious. This new virus was first detected in people in the United States in April 2009. The virus is spreading from person-to-person, in the same way that regular seasonal influenza viruses spread.

H1N1 flu is NOT caused by eating pork or pork products. H1N1 flu is not a foodborne disease, it is a respiratory disease.The USDA continues to remind consumers that all meat and poultry products are safe to eat when properly prepared and cooked.

It’s thought that influenza A (H1N1) flu spreads in the same way that regular seasonal influenza viruses spread, mainly through the coughs and sneezes of people who are sick with the virus, but it may also be spread by touching infected objects and then touching your nose or mouth.

H1N1 infection has been reported to cause a wide range of flu-like symptoms, including fever, cough, sore throat, body aches, headache, chills and fatigue. In addition, many people also have reported nausea, vomiting and/or diarrhea.

Illness with the new H1N1 flu virus has ranged from mild to severe. While the vast majority of people who have contracted H1N1 flu have recovered without needing medical treatment, hospitalizations and deaths have occurred.

About 70 percent of people who have been hospitalized with H1N1 flu have had one or more medical conditions that placed them in the “high risk” category for serious seasonal flu-related complications. These include pregnancy, diabetes, heart disease, asthma and kidney disease.

Unlike the seasonal flu virus, adults older than 64 do not yet appear to be at increased risk of H1N1 flu-related complications. Studies have shown that about one-third of adults older than 60 may have antibodies against this virus. It is unknown how much protection may be afforded against H1N1 flu by an existing antibody.

H1N1 flu is spread in the same way that seasonal flu spreads.Flu viruses are spread mainly from person to person through coughing or sneezing by infected persons. Sometimes people may become infected by touching something – such as a surface or object – with flu viruses on it and then touching their mouth or nose.

People infected with the seasonal or H1N1 flu shed virus may be able to infect others from 1 day before getting sick to 5 to 7 days after. This can be longer in some people, especially children or people with weakened immune systems.

Bacterial Co–Infections Common In Fatal Cases of Influenza Many people who have died from 2009 H1N1 influenza in the United States had co-infections with a common bacteria (Streptococcus pneumoniae, or pneumococcus) which likely contributed to their death including some caused by Streptococcus pneumonia, were noted in about a third of those cases.

Seasonal influenza is caused by viruses that have been interacting with humans for many generations. The human immune system is able to mount a quick immune response when encountering the same seasonal strain(s) again. The new 2009 H1N1 influenza, (formerly known as swine flu) emerged in the spring of 2009. Because humans have never been infected with this strain of the influenza virus, the immune system often cannot react as quickly or effectively as it can with familiar viruses.

While seasonal influenza is most threatening to those with weak immune systems, such as the very young and old, the 2009 H1N1 virus appears to be a threat to healthy, young adults, children and pregnant women. Although the populations most affected differ, the symptoms of seasonal and H1N1 influenza are very similar and can only be distinguished by a medical professional.

Oseltamivir is a potent and selective inhibitor of the neuraminidase enzyme of the influenza viruses A and B. The neuraminidase enzyme is responsible for cleaving sialic acid residues on newly formed virions and plays an essential role in the release and spread of progeny virions. When exposed to oseltamivir, the influenza virions aggregate on the surface of the host cell, thereby limiting the extent of infection within the mucosal secretions and reducing viral infectivity.

Oseltamivir pronounced (os el TAM ih veer) is a selective neuraminidase inhibitor. It is an antiviral drug that slows the spread of influenza (flu) virus between cells in the body by stopping the new virus from chemically cutting ties with its host cell. The drug is sold under the trade name Tamiflu and is taken orally in capsules or a suspension. It has been used to treat and prevent Influenza virus A and Influenza virus B infection in over 50 million people since 1999. Oseltamivir is readily absorbed from the gastrointestinal tract following oral administration and is extensively converted to oseltamivir carboxylate. Oseltamivir carboxylate is eliminated in the urine with a half-life of 6 to 10 hours. Oseltamivir becomes active in the body once it passes through the liver.

TAMIFLU (oseltamivir phosphate) is available as capsules containing 30 mg, 45 mg, or 75 mg oseltamivir for oral use, in the form of oseltamivir phosphate, and as a powder for oral suspension, which when constituted with water as directed contains 12 mg/mL oseltamivir base. In addition to the active ingredient, each capsule contains pregelatinized starch, talc, povidone K 30, croscarmellose sodium, and sodium stearyl fumarate. The 30 mg capsule shell contains gelatin, titanium dioxide, yellow iron oxide, and red iron oxide. The 45 mg capsule shell contains gelatin, titanium dioxide, and black iron oxide. The 75 mg capsule shell contains gelatin, titanium dioxide, yellow iron oxide, black iron oxide, and red iron oxide. Each capsule is printed with blue ink, which includes FD&C Blue No. 2 as the colorant. In addition to the active ingredient, the powder for oral suspension contains sorbitol, monosodium citrate, xanthan gum, titanium dioxide, tutti-frutti flavoring, sodium benzoate, and saccharin sodium.

Oseltamivir phosphate is a white crystalline solid with the chemical name (3R,4R,5S)-4­acetylamino-5-amino-3(1-ethylpropoxy)-1-cyclohexene-1-carboxylic acid, ethyl ester, phosphate (1:1). The chemical formula is C16H28N2O4 (free base). The molecular weight is 312.4 for oseltamivir free base and 410.4 for oseltamivir phosphate salt.