Influenza or the common flu is commonly known as `Flu` in most parts of the world. It is infectious and is caused by a virus called RNA. It belongs to the family of Orthomyxoviridae and affects birds and mammals.

The commonest indicators of this disease are chills, sore throat, fever, muscle pains, coughing, severe headache, general weakness and discomfort. In its severe form, influenza can also cause pneumonia and this can prove to be fatal, especially for those who are young and also the elderly. Influenza can also lead to nausea which may lead to vomiting in children, though these are symptoms in case of `stomach flu` only.

As a general rule, influenza is spread by air through a patient`s coughs and sneezes, which creates aerosols holding the virus. Bird flu can also spread due to bird droppings, saliva, feces, nasal secretions or blood. A person can get infected by coming in close contact with these bodily fluids or through contact with polluted surfaces. Most infections are a result of airborne aerosols, though which form of spread is most deadly is not completely clear till now. Common flu viruses are easily inactivated using detergents, disinfectants and sunlight.

Common flu spreads all over the world as seasonal epidemics, and results in thousands of deaths annually, sometimes the figure may touch the million mark too in a pandemic year. During the 20th century itself, 3 influenza pandemics occurred and millions of people died due to it. Each of the pandemic was a result of a unique species of virus in the humans. This generally happens when a prevalent virus is transmitted to humans from some other animal.

An avian virus by the name of H5N1 did ring an alarm bell as a new flu pandemic in Asia during the 90s, but till now it hasn`t evolved as a form which can spread easily between two people. Again in April 2009 a new strain of flu has evolved that has merged genes from pig, human, and the deadly bird flu. Dubbed as `swine flu`, it popped up in Mexico, US and also some other nations.

Symptoms of influenza tend to start all of a sudden, just one or two days after catching the infection. In most cases the initial symptoms are chills and a chilly sensation, though fever is also quite common from the early period only. Many people feel so ill and weak that they have to be confined to their beds for several days, with complaints of pains and aches throughout their bodies, especially in backs and legs. Other symptoms of common flu include aches in throat and joints, feeling very cold, fatigue, irritation in eyes or watering of eyes, headache, reddening of eyes, mouth, skin, nose and throat.

According to the WHO, every year tens of millions of people catch the common flu. For most people it is just means missing one week of work but elderly people run a high risk of death due to this. The worldwide death count due to this is nearly a few hundred thousand people. Common flu can affect even perfectly healthy people and at any age. But old people, children and people with chronic medical conditions can develop complications such as bronchitis, pneumonia, sinus or ear infections easily.

All over the world, common flu produces direct costs because of loss in productivity and related medical treatment, and also indirect costs due to preventative measures taken. In US alone it costs about $10 billion per year. Preventative costs can be quite high too. Worldwide governments have to spend billions of. dollars in preparation and planning for a probable avian flu pandemic in terms of drugs and vaccines along with developing disaster exercises and improving strategies on border controls.

What is swine flu?

Swine is the biological name that refers to pigs. Swine flu or swine influenza is a common viral infection that affects pigs all over the world. The influenza virus strains are responsible for all swine flu infections.

Symptoms in pigs

Swine flu causes fever and severe weight loss along with breathing problems in pigs. Though the flu is deemed to be severe, it rarely results in the death of the pigs. In most of the cases when the affected pig is pregnant, it results in the death of the baby pigs.

Since the flu has a very high proficiency of spreading quick and in large numbers, it results in huge monetary loss for the farm owners in terms of medical expenses and in the sale price of the pigs after cure.

Spreading of the disease among pigs

Once a pig is affected by the disease, it easily transmits the disease causing virus to the other pigs through various means. The most common is through direct contact with the healthy ones by touching each others’ noses. This along with sneezing or coughing directly spreads the virus through the atmosphere. It takes a maximum of only a couple of days to affect a whole farm of five hundred pigs. Once the existence of the disease is confirmed in a farm, the farm owners take utmost care to check each and every pig and segregate the healthy ones from the affected pigs.

Swine flu in humans

There have been very few occurrences of swine flu in humans in the past. When they did, the most probable infectors were the workers in the swine farms, especially those who directly work on the pigs. Though it is rumored that swine flu spreads through consumption of pork, scientists and researchers have confirmed that the probability of such occurrences are minimal. In addition, the disease very rarely spreads from humans to humans.

Symptoms in humans

Swine flu in humans causes acute fever, diarrhea sudden weight loss, dry coughing, pain in the muscles and joints and frequent dizziness as a result of weakness of the body.
Occurrences of swine flu in the world

There have been only a few occurrences of the original swine flu since the past century. The global outbreak of flu in 2009 that was suspected to be swine flu though is not actually the actual swine flu. The virus responsible for this pandemic disease is a result of a mixture of strands of the normal swine virus, human influenza virus and avian influenza virus. Since this is not a normal swine flu virus, it has the tendency of spreading from one man to another. This was first detected in parts of the United States and Canada. Within a matter of a week or two, the disease had managed to spread to almost all countries of the world. The WHO had released a worldwide alert on the spread of the disease and has also directed the countries to take the necessary measures to prevent it from spreading further.