Viruses

What is a virus?

Learning more about the H1N1 virus

Smallpox epidemic; SARS, AIDS and swine flu pandemic… Who does not recognize any of these diseases that have plagued the world? One would find it unimaginable that the single common denominator beneath these atrocities is the smallest infection-causing, protein-made, non-living agent- the virus.
Virus: The Basics
Viruses would only range from 20 to 300 nanometers in diameter. The well-known H1N1 virus, the causative agent behind swine flu, measures only 80-120 nanometers. Viruses can be grouped in a number of ways, the simplest of which is through their nucleic acid core: DNA or RNA. Take note that the H1N1 falls in the latter, the RNA core category.
Why are viruses classified as non-living things? Let us try to go back to elementary science and try to remember differentiating living from non-living things. In order for one to be classified as a “living” thing it must be able to all these requisites: metabolise, grow, reproduce and adapt. Viruses need to thrive inside the cell to live. They are made of single nucleic acid encased by a protein; and may be or may not be further surrounded by a lipid envelope. They use the cell’s machinery to reproduce themselves. They are not activated once outside the cell. However, they could adapt. This viral property is behind the h1n1 swine flu pandemic and other viral epidemics and pandemics.
Sounds complicated? To elaborate further on these interesting, not really human-friendly entities, it would be best to characterise one of the most familiar virus, the h1n1.
H1N1: the backgrounder
Influenza viruses, or the Orthomyxoviridae, are responsible for a significant number of respiratory illnesses world-wide. It is classified into influenza A, B or C based on their internal structural proteins. Only influenza A has subtypes one of which is h1n1. Subtypes are designated according to the type of H or HA (hemagglutinin) and N or NA (neuraminidase) it contain. Therefore h1n1 has HA subtype H1 and NA subtype N1.
Hemagglutinin and neuraminidase make up the viral envelope. They are important in the production of antibodies against the virus, evolution of new strains, reach target respiratory cells and therefore cause h1n1 symptoms. The single stranded RNA nucleic acid is an important property of the H1N1 virus. It would enter the cell’s nucleus in contrast to other RNA viruses within which viral transcription would occur.
The H1N1 virus was discovered last 2009 in the United States, and a swine flu pandemic occurring later the same year. Swine flu has derived its name because of its similarity to the one found in pigs in North America upon laboratory testing.
H1N1 symptoms=swine flu
H1N1 symptoms can range from the common cold to total exhaustion. The usual clinical manifestations would include: fever, sore throat, runny or stuffy nose, cough, body aches, headache, chills and fatigue. Vomiting and diarrhoea can also be present. Some may only have respiratory h1n1 symptoms without fever. Some may need h1n1 treatment, some may recover without any and some may even need hospitalizations, and worse result to death.
Common seasonal flu is very similar with h1n1 symptoms. They also have the same complications like pneumonia, bronchitis, sinus and ear infections. Therefore it is very important to identify risk groups in order to mitigate swine flu symptoms. This would include children younger than five years, elderly older than 65 years, pregnant women, those with chronic medical conditions and obese persons.
H1N1 and humans: the swine flu pandemic
Now that we have identified the important points about viruses, especially H1N1, the occurrence of the swine flu pandemic would be a little bit easier to understand.
As early as 1918, influenza has already wrecked havoc to the world by infecting one third of the world’s population, more or less 500 million people in the famous Spanish influenza. It was only a decade and a half after that isolates were acquired from birds and pigs then humans, thus the name swine flu and avian influenza. The swine flu pandemic on the other hand has caused 17,000 deaths worldwide and that nearly all countries of the world have reported cases in their locality.
Antigens serve as markers for body recognition of the pathogen and subsequent antibody production and immunity. Without the same antigens, antibodies are not produced and therefore the body cannot mount the same immunity to the virus. This would then lead to the manifestation of swine flu symptoms to a susceptible person. This mechanism occurs in influenza viruses. Hemagglutinin undergoes an antigenic shift which is remarkable in between pandemics. Humans who have mounted immunity from influenza A become re-infected and manifest h1n1 symptoms over again or whatever subtype that virus would have become.
Hopeful for H1N1 treatment
Pharmaceuticals have a very small role in H1N1 treatment. Treatment is largely supportive and does not include anti-virals. Supportive H1N1 treatment includes bed-rest, increased water intake, cough suppressants, antipyretics (such as paracetamol) and analgesics (such as mefenamic acid) for fever and muscle pain.
Anti-virals are useful as H1N1 treatment only within the first 48 hours from the onset of symptoms. These would include osetalmivir and zanamivir. Evidence supports that the former significantly decreases the risk for subsequent pneumonia and the need for hospitalization and therefore is vital in H1N1 treatment.
Treatment is also indicated in severe illness even when started beyond 48 hours. This applies to all age groups including pregnant women.
An investigational antiviral drug, Peramivir, has been observed as an effective h1n1 treatment when applied in emergency investigative drug programs in the US. Major recovery from severe swine flu infection was noted in hospitalized patients.
Nothing beats prevention
The good ol’ saying “prevention is better than cure” is best applicable in swine flu and other diseases caused by influenza, especially seasonal flu. The Center for Disease Control or CDC found a way to circumvent the antigenic shift by annual surveillance of existing influenza virus strains and producing the annual flu vaccine. The individuals at risk that were mentioned earlier are highly advised to get their annual flu shot from their friendly physicians to prevent swine flu symptoms.
When you are already sick with flu, one should take note of coughing and sneezing ethics when positive with h1n1 symptoms. Transmission from person to person through coughs and sneezes. The h1n1 virus could also be acquired from surfaces (like doorknobs, computers and phones) so never forget to always wash your hands. It is also very important to stay away from people as you would most likely transmit the virus. Give yourself a break from school or work. You would need bed-rest to recover and minimize the chances of others getting sick with swine flu.

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