What is H1N1 virus?
H1N1 flu is a subtype of influenza A virus (a communicable viral disease), which causes upper, and potentially, lower respiratory tract infections in the host it infects.
Why H1N1 virus is also known as swine flu virus?
H1N1 swine influenza is a common infection in pigs worldwide, and that is why it is also known as swine flu. H1N1 swine flu leads to respiratory disease that can potentially infect the respiratory tract of pigs.
What does H and N stand for in H1N1?
Swine flu virus is an orthomyxovirus that contains the glycoproteins hemagglutinin (H) and neuraminidase (N), antigens whose subtypes are used to classify the strains of the virus as H1N1, H1N2 etc.
Hemagglutinin causes red blood cells to clump together and binds the virus to the infected cell.
Neuraminidase is a type of glycoside hydrolase enzyme which helps to move the virus particles through the infected cell and assist in budding from the host cells.
Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a small fraction of all seasonal influenza. Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza).
How humans get swine flu?
Sometimes, people who are closely associated with pigs or in the proximity of pigs have developed swine flu (zoonotic swine flu). Swine influenza viruses can potentially cause infections in humans if antigenic characteristics of the virus change through reassortment. When this happens, transmission from person-to-person is usually inefficient. Influenza A pandemics such as the ones in 1918 and 2009 can occur if the transmission from person-to-person becomes efficient.
Despite the name, an individual cannot acquire swine flu from eating pig products such as bacon, ham, and other pig products.
What are the symptoms of swine flu?
H1N1 swine flu is an acute disease that infects the upper respiratory tract and can cause inflammation of the upper respiratory passages, trachea, and possibly the lower respiratory tract.
It results in symptoms such as nasal secretions, chills, fever, decreased appetite, and possibly lower respiratory tract disease.
What were the major outbreaks of swine flu in the past?
In 1918, a deadly influenza pandemic caused by H1N1 influenza virus, also known as the Spanish flu, infected approximately 500 million people around the world and resulted in the deaths of 50 to 100 million people (3% to 5% of the world population) worldwide, distinguishing it as one of the most deadly pandemics in human history.
In 2009, a new strain H1N1 swine flu spread fast around the world among humans, and the World Health Organization (WHO) labeled it a pandemic. However, the 2009 H1N1 virus was not zoonotic swine flu because it was not transferred from pigs to humans. Instead, it spread through airborne droplets from human to human, and potentially, through human contact with inanimate objects contaminated with the virus and transferred to the eyes or nose. This virus caused similar symptoms to those seen in swine, possibly due to reassortment of the viral RNA structure, which allowed human-to-human transfer.
What is the incubation period for H1N1 swine flu?
The known incubation period for H1N1 swine flu ranges from 1 to 4 days, with the average around 2 days in most individuals, but some individuals, it may be as long as 7 days.
PRACTICE QUESTIONS
QUES. H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases? UPSC 2015
(a) AIDS
(b) Bird flu
(c) Dengue
(d) Swine flu
(d) Swine flu
