Swine Flu (H1N1 Flu Virus): A Short Commentary

Himabindhu Gude^*
*Correspondence: Himabindhu Gude, Department of Biotechnology, India, Tel: +918143389651, Email:

H1N1 Flu Virus

H1N1 flu is also called as swine flu. It is caused due to Influenza virus which belongs to the family Orthomyxoviridae. The influenza viruses are classified into three types A, B and C depending on the core proteins. Only types A and B cause human disease.

Humans are mostly infected by viruses of the subtypes H1, H2 or H3, and N1 or N2.

A human respiratory infection which is caused by an influenza strain that started in pigs. Swine flu was first recognised in 1919 pandemic and circulates as a seasonal flu virus still. It is caused by the H1N1 virus strain.

Influenza viral infection is an acute respiratory infection varies on the severity of infection from asymptomatic to fatal disease. Typical influenza infection symptoms includes fever with abrupt onset, chills, non-productive cough, sore throat, and often accompanied by headache, coryza, myalgia and prostration. Complications of influenza infection includes: primary influenza viral pneumonitis, bacterial pneumonia, otitis media and exacerbation of underlying chronic conditions. Illness tends to be most severe in the elderly, in infants and young children, and in immunocompromised hosts. Death occurs mainly in elderly and in the individuals with pre-existing chronic diseases. Influenza type A (H1N1) is similar to seasonal influenza characterized by the higher activity during the summer season; fatality rates are higher among the healthy young adults and higher incidence of viral pneumonia.

Influenza occurs all over the world, with an estimated rate of 20–30% in children and 5–10% in adults. In temperate regions, influenza is a seasonal disease occurs in winter months: it affects the southern hemisphere from April to September and from November to April in the northern hemisphere. Tthereis no clear seasonal pattern in tropical areas, and it circulates throughout the year, typically with several peaks during rainy seasons.

Travellers are at high risk in any country during the influenza season. In addition, groups of travellers that include individuals from areas affected by seasonal influenza (e.g. cruise ships) may experience out-of season outbreaks. Travellers visiting countries in the opposite hemisphere during the influenza season are at special risk, particular if they do not have some degree of immunity through recent infection or regular vaccination. The elderly, people with pre-existing chronic diseases and young children are most susceptible to complications.

Avoid crowded enclosed spaces and close contact with people suffering from acute respiratory infections if possible. Frequent hand-washing, after direct contact with ill persons or their environment, may reduce the risk of acquiring illness. Ill persons should be encouraged to practise cough etiquette (maintain distance, cover coughs and sneezes with disposable tissues or clothing, wash hands).

On 10^th August 2010, WHO Director-General Dr. Margaret Chan announced H1N1 influenza virus has moved into the post-pandemic period.