What started as an epidemic of swine flu in Mexico in March 2009 has now spread to 100 countries. The World Health Organization (WHO) has been alerting countries for the past eight years to get prepared for a major influenza outbreak. It seems to have finally arrived.

H1N1 virus moved from pigs and went on to infect humans, facilitated by crowded living conditions. From Mexico it spread to the United States, then to Europe and Asia. In the US, swine flu has so far killed 436 people and infected about 100,000 people. The situation will get worse as winter approaches parts of the world.

India has seen 21 deaths so far and this is causing panic among the populace. The good news is that the vast majority of the people who contract swine flu influenza are going to recover completely after going through a period of body aches, sore throat and fever.

If the Mexican experience is any guide, the H1N1 swine flu is sometimes lethal in children and young adults. This seems to be the pattern in India also. People born before 1957 appear to have some protection from the current pandemic. In the 1918 pandemic, it is estimated that close to 50 million people perished in different parts of the world.

In 2009, healthcare is very advanced compared to 1918. Tamiflu tablets if taken early may minimise the severity of the disease. But if Tamiflu is used indiscriminately, the virus will adapt and become resistant to the drug. Governments have stock piled millions of tablets to be used in a major outbreak.

The influenza virus sometimes settles down in the lungs and can cause severe respiratory distress requiring mechanical ventilatory support. Of the 2,155 cases of viral pneumonia reported from Mexico, 821 required hospitalisation and 100 died of respiratory failure in spite of mechanical ventilation. Not all viral pneumonia cases need ventilatory support.

Pharmaceutical companies are racing to bring a vaccine that could be effective against the swine flu virus. Pilot clinical studies are going on in America.