Swine influenza (also called swine flu, hog flu, and pig flu) is an infection of a host animal by any one of several specific types of microscopic organisms called ‘swine influenza virus’. A swine influenza virus (SIV) is any strain of the influenza family of viruses that is usually hosted by (is endemic) in pigs. At present, the known SIV strains are the Influenza C Virus and the subtypes of the influenza A virus known as H1N1, H1N2, H3N1 H3N2, and H2N3. Swine influenza is common in pigs in the midwestern United States (and occasionally in other states), Mexico, Canada, South America, Europe (including the United Kingdom, Sweden, and Italy), Kenya, China, Taiwan, Japan and other parts of eastern Asia.

Novel influenza A (swine flu) is a new flu virus of swine origin that was first detected in April, 2009. The virus is infecting people and is spreading from person-to-person, sparking a growing outbreak of illness in the United States. An increasing number of cases are being reported internationally as well. In India also several cases of swine flu have been detected, with over 20 people losing their lives. A majority of them have been affected by tourists and travellers coming from outside the subcontinent.

It is thought that swine flu spreads in the same way that regular seasonal influenza viruses spread; mainly through the coughs and sneezes of people who are sick or prey of the virus. It’s uncertain at this time how severe this swine flu outbreak will be in terms of illness and death, compared with other influenza viruses. Because this is a new virus, most people will not have immunity to it, and illness may be more severe and widespread as a result. In addition, currently there is no vaccine to protect against this swine flu virus for which it is anticipated that there will be more cases, more hospitalizations and more deaths associated with this new virus in the coming days and weeks to come.

Early surveillance data from this outbreak suggest that the novel influenza A (H1N1) virus has the potential for efficient, rapid spread among countries. Although the illness associated with infection generally seems self-limited and uncomplicated, a substantial number of cases of severe disease and death has been reported in previously healthy young adults and children. Several characteristics of this outbreak appear unusual compared with a typical influenza seasonal outbreak.

Summertime influenza outbreaks in temperate climates have been reported in closed communities such as prisons, nursing homes, cruise ships, and other settings with close contact. Such outbreaks typically do not result in community-wide transmission, but they can be important indicators of viruses likely to circulate in the upcoming influenza season. The H1N1 virus has been circulating in North America largely after the peak influenza transmission season. For that reason, the epidemiology and severity of the upcoming influenza season in the southern hemisphere or in the northern hemisphere cannot be predicted.

The imminent onset of the season for influenza virus transmission in the southern hemisphere, coupled with detection of confirmed cases in several countries in the southern zone, raise concern that spread of H1N1 virus might result in large-scale outbreaks during upcoming months. Countries in the southern hemisphere that are entering the influenza season should anticipate outbreaks and enhance surveillance accordingly. Influenza virus can circulate year round in tropical regions; therefore, these countries should maintain enhanced surveillance for novel influenza A virus.

Studies in countries affected by the novel influenza A virus should help guide surveillance, case management, and prevention strategies in countries not yet affected. Effective control measures will depend on the ability of national governments to quickly gather and share virologic, epidemiological, and clinical information from multiple sources as new cases appear.

The novel H1N1 flu virus is causing illness in infected persons in the United States and countries around the world. Common symptoms include fever, headache, tiredness, cough, sore throat, runny nose, body aches, diarrhoea, and vomiting. The high risk groups for novel H1N1 flu are not known at this time but it’s possible that they may be the same as for seasonal influenza. People at higher risk of serious complications from seasonal flu include people aged about 65 years and more, children younger than five years old, pregnant women, people of any age with chronic medical conditions (such as asthma, diabetes, or heart disease), and people who are immune-suppressed (e.g., taking unsuppressed medications, infected with HIV).

If a person is sick, they may be ill for a week or longer. Therefore, the concerned person should stay home and avoid contact with other persons, except to seek medical care. If one leave the house to seek medical care, one should wear a mask or cover one’s coughs and sneezes with a tissue. In general, one should avoid contact with other people as much as possible to keep from spreading the illness. Seasonal flu studies have shown that people may be contagious from one day before they develop symptoms to up to seven days after they get sick. Children, especially younger ones, might potentially be contagious for longer periods.

There are two influenza antiviral medications that are recommended for use against H1N1 flu. The drugs that are used for treating H1N1 flu are called oseltamivir (trade name Tamiflu®) and zanamivir (Relenza®). As the H1N1 flu spreads, these antiviral drugs may be in short supply. Therefore, the drugs will be given first to those people who have been hospitalized or are at high risk of complications. The drugs work best if given within two days of becoming ill, but may be given later if illness is severe or for those at a high risk for complications.

If one becomes ill and experiences any of the following warning signs, one should seek emergency medical care.

In children, emergency warning signs that need urgent medical attention includes:

• Fast breathing or trouble in breathing.

• Bluish or gray skin colourization

• Not drinking or inability in drinking enough fluids.

• Severe or persistent vomiting.

• Not waking up or not interacting.

• Being so irritable that the child does not want to be held.

• Flu-like symptoms improves but then return with fever and worse cough.

In adults, emergency warning signs that need urgent medical attention includes:

• Difficulty in breathing or shortness of breath

• Pain or pressure in the chest or abdomen

• Sudden dizziness

• Confusion

• Severe or persistent vomiting

• Flu-like symptoms improve but then return with fever and worse cough

Some measures of protecting oneself, one’s family, and the community.

• One should stay informed. Health officials will provide additional information as it becomes available. One should receive treatment only from a government hospital or public health centre.

• One should cover one’s nose and mouth with a tissue when one coughs or sneezes. Throwing the tissue in the trash or a bin is very mush essential.

• Washing one’s hands often with soap and water, especially after one coughs or sneezes is very important. Alcohol-based hand cleaners are also effective in this purpose.

• Avoiding touching one’s eyes, nose or mouth is essential. Germs do spread this way.

• One should try to avoid close contact with sick people.

• If a person is sick with a flu-like illness, one should stay home for seven days after the symptoms begin to surface. Stay in until one becomes symptom-free.

• One should keep away from other household members as much as possible. This is to keep one from infecting others and spreading the virus further.

• Follow public health advice regarding school closures, avoiding crowds, and other social distancing measures.

• If one is not affected still one considers developing a family emergency plan as a precaution. This should include storing a supply of extra food, medicines, and other essential supplies.

Bedabrata Das