‘Swine’ is not a nice word. We use it in a derogatory sense to describe people we don’t much like. ‘Pig’ on the other hand is fairly neutral. It could indicate a likeable animal. “The three little swine and the big bad wolf someone does not seem appropriate. Hence it is not surprising that the influenza pandemic, which no one can help but hear about, has been labelled ‘swine’ and not ‘pig’ flu.
It is caused by a virus that originally infected pigs and was labelled ‘H1’. This occasionally infected humans but, importantly, did not spread from person to person. As most of us are less likely to meet a pig than another human being, this meant the virus had a limited chance of spreading.
Viruses, which are one of the most basic of living beings, essentially consist of strings of DNA or RNA, which are the building blocks of all life. Viruses can change their DNA (or RNA) sequence fairly easily during replication, helping them evade the immune system of their hosts. This change can sometimes alter the character of the virus. The HI virus, which infected mainly pigs, did just that. The new avatar had the important characteristic of spreading from human to human; this change was of sufficient importance for it to acquire a new addition to its label.
Thus was born the H1n1 virus. Its DNA sequence is a mix of DNAs from three different viruses, affecting birds, pigs, and humans. Occasionally a human could infect a pig with H1N1 but the infection is predominantly among humans. The first time the H1N1 virus infected humans was in 1918. Over the years, several epidemics have occurred by similar strains, which were also called Human Influenza A (seasonal) and were also H1N1. The current pandemic probably resulted from cross transmission from pigs again, the first case occurring in a 17-year-old in Wisconsin, USA in 2008. This strain is sometimes referred to as S-OIV.
Viruses produce a wide range of diseases. Influenza, common cold, polio, small pox, chicken pox, encephalitis, rabies, and measles are some of the well known ones. Many viruses are yet to be identified and named but can still cause serious disease. Hundreds and possibly thousands of children die everyday in India from acute respiratory infections and acute gastroenteritis, often caused by viruses. Overcrowding, poor hygiene, and malnutrition increase the chances of not only getting infected but also dying of it.
The swine flu, like most flu, affects mainly the respiratory system. This facilitates its spread as the viruses travel through droplets dispersed while sneezing or coughing. The typical symptoms are fever, cough, body pain, lethargy and, in severe cases, mental obtundation and respiratory failure. When the patient dies, the virus dies. Hence, overtime, the more virulent strains die out and subsequent infections are milder. The flu viruses generally spread, almost inevitably, to infect large sections of the population in the course of a few months unless effective vaccines are developed and deployed quickly for the entire population. But vaccines can cause problems and the occasional fatality too.
For milder infections like the common cold and the milder forms of flu, it may be better to allow the spread of sub-clinical or mild infection for natural immunity to develop in the community. The H1N1 (S-OIV) virus is estimated to have infected about 2.5 million people in the United States. Previous epidemics of similar viral infections have left behind sufficient innate immunity in many, protecting them from fresh infection with the current pandemic.
Antibiotics have no effect against viruses. Specific anti-viral agents, namely Ostelamivir (Tamiflu), are effective against H1N1 if used early, preferably within the first two days. However, as early symptoms are non-specific, potentially millions of people with ordinary viral infections like the common cold will have to be tested and/or treated with anti-viral agents. Such a strategy may be impractical and without established benefit.
Swine Flu (H1N1 S-OIV) is one among many infections caused by viruses and bacteria. Many of these infections are more infections and dangerous than swine flu in India. TB kills a thousand people in India every day.
1. Most cases of swine flu are likely to recover with or without Tamiflu.
2. The virus may get less virulent with time.
3. Many may already have natural immunity against the virus.
4. In course of time, a significant proportion of the population will test positive for swine flu due to swine flu infection without disease. Because of this, there may be a danger of misdiagnosing many other conditions for swine flu.
Possible beneficial outcomes:
1. Greater awareness of the nature of infections and their spread. Better hygiene and preventive methods for all infections may evolve.
2. Preventive methods may curb the spread of their infections like TB.
3. The government and the public may become more aware of the lacunae in health care delivery and corrective steps may be taken.
Possible deleterious effects of excessive publicity:
1. Mass hysteria and panic, leading to inappropriate and useless actions.
2. Diversion of scarce funds from other badly needed areas to activities with little benefit.
3. False expectations of medical interventions from doctors and institutions.
