H1N1, influenza A virus type has been in the news for a long time and it seems as if it is here to stay, because a column in the newspapers still reads the death toll due to this fatal virus. It is most commonly called the Swine Flu. Why is it called the Swine Flu? If the name suggests the natural host of the virus is the Swine, then how are we human beings being affected the most? Why the term pandemic associated with it? The World Health Organization has termed H1N1 pandemic.
What is Pandemic?
The word Pandemic is derived from the Latin word ‘pandemos’, meaning of the people. In other words, it means that it is an epidemic spread over a wide geographical area affecting a large proportion of the population. Epidemics in contrast involve a very small community or a single state or a single village or even as small as a single family.
The WHO has declared the Swine Flu as a pandemic as it has spread over several continents having originated in Mexico. India is one of the countries that have been affected with about 1060 deaths and Gujarat alone has about 250 deaths (Report by Press Trust of India, 7 Feb. 2010) registered due to this deadly virus.
Why is it called Swine Flu?
H1N1 is a swine influenza virus (SIV) endemic in pigs. SIVs are of Influenza C type and some subtypes of Influenza A virus which includes H1N1, H1N2, H3N1, H3N2 and H2N3. Pigs are the natural hosts for these viruses throughout the world and it is very rare that such viruses are transmitted to humans. When transmitted to humans causing influenza, it is called zoonotic (transmission from non-human to human) swine flu. However, there are chances that people frequently exposed to pigs may get infected. Pork eating population may be susceptible but only if it is not cooked properly (J Midwifery Womens Health. 2009; 54(6):517-518. © 2009 Elsevier Science, Inc.).
The ability of viruses to change their hosts is attributed to genetic changes. This is also known as antigenic shift. The flu strain could have originally been present in a bird or a duck or any aquatic animal, which then shifted to a chicken, then to a pig and then finally to a human. This transmission from one host to the other host would have been possible only because of changes in the genetic make up. This is how presumably the swine flu must have infected the humans (Reported by National Institute of Allergy and Infectious Diseases (NIAID). Researchers found that the virus was derived from several viruses circulating in swine, and that the initial transmission to humans occurred several months before recognition of the outbreak (Smith GJ, et al. Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic. Nature. 2009 Jun 25;459(7250):1122-5).
Symptoms of zoonotic swine flu in humans are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. The recommended time of isolation is about five days.
Treatment of Swine Flu
The best treatment for H1N1 is vaccination. The first vaccine introduced in October 2009 was a nasal spray vaccine and contains live attenuated viruses. Attenuated viruses are viruses that are living but with weak virulence and hence not able to cause the disease. However, there is always a risk of its reverting back to its virulent form and hence should not be given to pregnant, immunocompromised and elderly people.
Two antiviral agents have been reported to help prevent or reduce the effects of swine flu. They are Relenza and Tamiflu, both of which are also used to prevent or reduce influenza A and B symptoms. Latest research by scientists at UTAH State University (Funded by NAID) also suggested that a combination of two drugs could be effective in treating Swine Flu. The research was carried out on mouse model and the results suggest that the combined drug treatment is better than an individual drug treatment.