Swine flu is an example of nature’s ingenuity in remaining one step ahead of medical science. Its the classical Darwinian theory of evolution at play. Simply put, organisms develop variations that increase their probability of survival and its the differential survival of variants that fuel the epidemics.
They ceaselessly roam the blue earth, seeking red blood. They are among us, yet forever apart. They are legion, yet invisible. They are undead”
Historically, viruses have been perceived as enigmatic organisms transcending the boundary between living and non living, evoking fear and hysteria for its mysterious ways.
Why flu epidemics happen anyway?
As a survival strategy, influenza virus undergoes random changes in genetic code producing newer variants every year. These antigenic changes means that the human body is no longer able to mount an adequate response to the newer variant. This is why a new flu vaccine is needed each year. This annual cycle of genetic change ensures that a critical mass of vulnerable population is readily available for sustenance of the virus. The vulnerable population, however, progressively reduces over successive years. Usually after several decades, the pressure on the virus escalates leading to bigger genetic changes, thus producing new sub type of the virus. Such an eventuality renders the entire population susceptible to the new variant within a relatively short window of time, thus triggering pandemics. The most recent genetic shift took place in 2009. In the intervening years, the new H1N1 virus has established itself as the regular circulating sub type of influenza. A detailed history of influenza epidemics can be accessed here.
Where do swines come into the picture
Different viral strains capable of infecting different animal species, when present at the same time in a single species, undergo genetic re-assortment. Pigs are excellent reservoirs for this natural mixing of flu virus sub types. That is why the genetic shift leading to global pandemics are generally derived from pigs and are, therefore, colloquially referred to as swine flu.
To be or not to be: The scramble for vaccination and Tamiflu
Much can be learned from the history of pandemics. Historical data on influenza outbreaks have shown that by the time a type-specific vaccine comes on the ground it is often too late for it to have any benefit. Moreover, development of immunity after vaccination takes up to 3 weeks, by which time the peak of transmission is already over. (Related news on flu vaccine limitations below). Indiscriminate use of antiviral treatment is also not recommended owing to the risk of development of newer drug-resistant variants. Restricting unnecessary exposure and personal prophylaxis, then, is a practical way to prevent getting infected in the ongoing swine flu. epidemic. Indiscriminate vaccination and off the counter use of Tamiflu can do more harm than good. There is no substitute for medical consultation for assessing one’s risk and taking recourse to specific interventions. Compliance with the government guidelines is a key imperative if we are to ward off the ongoing threat of swine flu.
.…to be concluded
Link: National Health Portal (NHP) of India website for updated information on swine flu