H5N1- Potental WMD

Attended an intriguing lecture on the 'Facts about Bird Flu' today by Dr. Shahid Jameel, Group Leader, Virology, ICGEB (International Centre for Genetic Engineering and Biotechnology), New Delhi in my centre. Learnt a lot.

Since 2003, 173 people have been infected and out of them 93 have died, so the mortality rate for those testing positive for the virus is pretty HIGH. What the good doctor wanted to bring out was the fact that the majority are NOT testing positive or remain asymptomatic.

Now heading towards the biology of it, ever so fascinating a topic for me( I wish to think that one of the parallel 'me' in another universe is definitely a genetic engineer or something taking a cue from Richard Bach's reflections). Anyways, it is a known fact that all varieties of influenza - Type A (see picture)- are found in birds. It is the Type B and C that infects only mammals and which differs substantially from the former.


If you look closely at the adjoining image, the virus has two significant proteins on its surface, hemagglutinin (HA) and neuraminidase (NA). There are 15 subtypes of HA and 9 subtypes of NA proteins, so in all 135 different strains of influenza Type A known to exist. However, kudos to our endeavours in this field, the speaker was duly corrected by another scientist who has devoted three and a half decades to the field, that now we know the respective figures are 16, 9 and 144. RNA (Ribonucleic Acid) is the genetic material of the virus and it is because of the segmented nature of its genome (eight different segments instead of one long strand of nucleic acids) that it mutates often and remains a MYSTERY.

We now reach the root of the problem - MUTATION. The genetic material of this seemimgly casual virus is RNA which replicates without any proof reading. Needless to say that errors are thus introduced galore. This is referred to as 'antegenic drift' and there is no escaping it. Then there is 'antegenic shift' which refers to the inter-mixing between two or more viruses feasting on the same innocent cell. (trying to make biology a bit fun to read with oxymorons, kindly excuse.) So say if H2N2 and H3Nx virus fool around, we get H3N2 virus. They say pigs being susceptible to both bird and human infuenza virus, are most likely to play the perfect host (or mixing vessel) to them.

On an average, we expect three such major outbreaks per century and the last one we endured was in 1968. So, if one does the math, we are practically sitting on a virtual TIMEBOMB. As of now there is no reason to panic but due to the forces of mutation at work, we fear that the virus could one day mutate its way to become a type capable of conveniently jumping from one human to another.

Animal Husbandary practices in China and South-east Asia, where humans, pigs and poultry live in close proximity, are being blamed for this outbreak unlike the mechanized farms in the west. Migratory birds are the natural reservoirs which means that they aid the tranmission of the virus without itself being falling prey to it. Next in the chain are domestic ducks, followed by poultry (pigs in particular- the mixing vessels remember) and they may finally act as a bridge across to get to US. As of now, the human to human tranference is extremely rare with only one such case reported to date that of a child to mother spread in ctober, 2004 in Thailand.

The incubation period of the virus is between 2-8 days and it spreads in the form of large droplets. Primary symptoms include fever (threshold 38 degree centigrade), cough with sputum, sore throat, rhinitis (inflammation of the nasal mucous membranes), muscle aches (geez have all of that right now!!!!), diarrhoea followed by (God forbid) the eventual cause of death -breathlessness caused by pneumonia (accumulation of fluids in the lungs).

Now to the testing facilities available. They say the timing of the antigen test is very crucial in detecting the virus (should be done in the first 2-3 days)as the viral load (its amount) gradually decreases in an infected person. RNA (genetic) testing is more sound in this regard. Thanks to the indiscriminate use of drugs developed for humans in poultry by overzealous animal husbands :), the virus is now resistant to the majority of them. Oseltamivir (popularly known as Tamiflu) is one of the vaccines available but indiscriminate exposure to it may make the virus resistant to the former in no time as well. On an average once an outbreak takes place, a minimum of 4-6 months are required to develop an egg-based vaccine (wherein a lab flu virus and the killer virus are injected into an egg and allowed to fool around yet again to obtain what we call an atenuated virus). The trouble with H5N1 virus is that it is highly pathogenic to eggs so probably working at the molecular level (Genetic engineering to the rescue) seems like a better bet.

The question arises 'Why did India join the bandwagon only recently?' Thankfully, we don't import poultry at all (so blanket bans do work wonders at times), the east Asian bird migration paths go around India and majority of our farmers relish a cow in their backyards not poultry. However, poor surveillance, live bird markets and a high population density do not augur well for our chances of beating this menace.

The speaker wrote an article titled 'The Birds are coming. Are we Ready?' in the Indian Journal of Medical Research in October, 2005 where he enlisted a To-Do list for the government. It was heart-warming indded to hear him praise the government's prior surveillance and response once the birds did land (so to speak). Cipla has already started the production of generic drugs and reiterated that India possesses good manufacturing and testing capabilities. Do you know that 90% of measles vaccine in the world are produced in India!

February 18, 2006 saw the confirmation of the presence of the virus in Navapur, Maharashtra followed by Surat, Gujarat. The two places (fairly close to each other) are near major wetlands (resting places for the migratory birds).

The speaker stressed upon the fact that perceptions are more important than actions and expressed his shock on learning that the Health Secretary ate chicken on TV while the government ordered removal of chicken off the menu in Parliament, railways and the national airlines (recently christened as Indian). The Press, he believed, had a crucial responsibility in allaying public's fears and reducing the highly prevalent PANIC. A proper chain of command in releasing the much needed information was idispensable as well. The Union Government's Department of Animal Husbandry, Darying and Fisheries has prepared an Action Plan which states that once an outbreak is confirmed, culling must take place upto 3 km diameter and vaccination started from the 10 km from outside - in. 3-10 km from the epicentre is designated as the surveillance zone where as of now culling instead of vaccination is taking place owing to allegedly lesser number of poultry involved.

He left the audience after voicing a warning of sorts. The presentation screen portrayed a foggy night with a sign which read 'FLU AHEAD'. In the background, there were a couple of lights and he said, "We do not know whether that is light at the end of the tunnel or the headlights of a truck heading directly towards us."

N.B- President Bush on his recent visit to India welcomed the latter's offer to host the International Partnership on Avian and Pandemic Influenza Meeting in 2007. Way to go!