Swine Flu – What is it and How to Avoid It

Basic Knowledge

Swine Flu is caused by Influenza virus A (H1 N1). We need first to explain what’s type A and what are H & N. Influenza viruses are divided into 3 main categories A,B&C ; A virus causes world wide epidemics (pandemics) of influenza , B virus causes major outbreaks while C virus only causes mild respiratory tract infection. The pandemics caused by influenza A virus occur nearly every 10-20 years, but major outbreaks caused by this virus occur virtually every year in various countries.

The key to the persistence of the influenza virus is its genetic material and antigenic composition. It’s major surface antigens are hemagglutinin (H) and neuraminidase (N). The H antigen is used to bind to host cells, while N Antigen cleaves budding viruses from infected cells. Hemagglutinin has 4 subtypes (H1, H2, H3 and H5) and N antigen has 2 (N1 and N2) that have caused human disease. The surface antigens can change or (shift) over time. H & N Antigens change continuously reflecting mutations in their genetic material where antigenic shift occurs when a major change occurs in the antigens and this shift often triggers a pandemic, because humans often have little or even no pre-existing immunity to the new strain.

Mode of infection

Swine flu virus spread like any other influenza virus by droplets or aerosols.

Incubation period

1-4 days ( The period before appearance of symptoms).

Clinical manifestations

Unfortunately swine flu has the same symptoms like usual human flu and this includes:

Sudden increase of body temperature, cough, malaise , anorexia ,