Flu: be alert and a little alarmed

I long ago wearied of correcting patients - or friends - who complain  ‘I’ve got the flu’, when clearly what they have is the common cold.  People tend to use the terms ‘flu’ and ‘cold’ interchangeably, and if they want to be more dramatic (and perhaps justify coming to the doctor or taking time off work), they tend to coin the word ‘flu’.

However, if you have ever had the ‘flu yourself, you will be very certain of the difference.

I’ve had it once, during the last ‘pandemic’.  This was the so-called Hong Kong flu, which was around in 1968-1970 and killed about one million people worldwide.  I was still at school, so having to spend almost three weeks off didn’t seem like the end of the world. But since the first week was spent shivering and shaking, spiking fevers and enduring muscle aches and pains, and the subsequent two trying to remain upright and alert for at least a few hours per day, it is certainly not something I would put my hand up for again.   Since then, I have had a flu vaccination virtually every year, and avoided anything worse than a bad cold.

On a practical level, 'flu is not a cost effective way for any self-employed person to have some time off work.  Just as inconvenient is having your staff get the 'flu:  the average person with 'flu needs an average of 5 days off work, and is infectious for up to two days even before they develop symptoms.  If they soldier on (or, more likely, if you do), work efficiency is estimated to be reduced by about 50%.

About 20-30% of Australians are infected each winter, and around 4000 of us die.  The ordinary 'flu (as opposed to pandemic strains) tends to infect the old and frail and chronically ill, but no one is immune.  Those who work in health related industries are more vulnerable and are therefore encouraged by the Dept of Health to be vaccinated. That includes dental health professionals, who are exposed to gaping buccal cavities on a daily basis.  'Flu is also highly infectious, so even if you, as the vaccinated person, avoid getting infected (and the vaccine is over 70% effective), one of your staff may get it and transmit it to others.  This year’s vaccine is available now.

'Flu is transmitted very effectively between people by what microbiologists call ‘droplet contamination’.   Every time someone within 10 metres of you coughs or sneezes, they generate a high velocity aerosol, which envelops you.  If they are carrying bugs, such as the flu virus, you are drenched in a fine mist of the virus.  Even if the person covers their nose/mouth with a tissue (and how many people manage it in time?), the number of viruses spread is in the millions.  The best way to spread viruses is by employing a cloth handkerchief or using a pre-used tissue. If you see someone get a crumpled handkerchief out of their pocket and give it a little shake, run for cover. That movement alone causes all the desiccated bugs from previous use to be propelled in all directions. And because they are dried, they can fly further.  Once they make contact with a warm moist mucosal surface (your nasal passages, throat, mouth), they can flourish. Handkerchiefs may seem like a good idea ecologically and aesthetically, but they are a microbiological disaster.

There are always one or two 'flu bugs circulating at any time, but we tend to get infected in autumn and winter.  This is largely because we crowd together more then, in warm buses, trains or pubs, and breathe in shared air and get repeatedly sprayed with aerosols of human nasopharyngeal secretions. We do not catch bugs because we got caught out without a coat, or sat in a draught or on a wet rock.  Poor old Pasteur spent years proving his germ theory but it seems to have passed many people by.

'Flu has always been around and occurs as types A, B and C.  Type C rarely infects humans, Type B causes mild human epidemics and Type A, found only in birds, causes more serious infections if it mutates to infect humans.

Bird' flu (or avian influenza) is a Type A.  There are about 15 types of these and they are easily passed from wild migratory birds to domestic poultry, killing them quickly.  Animal to human infection is rare, but the strain H5N1, first identified in 1997, is capable of this, and is the one getting all the attention now.  About 200 people have been infected worldwide in the past 12 months and half of these have died.  It is feared that H5N1 will be the cause of our next pandemic.

Pandemic refers to the emergence of a new strain of a disease which no one has prior immunity to, and which infects 25% or more of the population.  It refers only to diseases affecting humans and which are easily spread.  It is an epidemic on a global scale, an epidemic being when more cases than expected of a disease occur, confined to one area or country

'Flu pandemics appear to have been occurring since we have been living together in groups, and generally every 30-40 years.  Three pandemics occurred last century: the so-called 'Spanish 'flu' in 1918-1819, now thought to have actually originated in the USA. The deaths caused by this one are estimated at up to 50 million.  Next was the  ‘Asian flu’ pandemic of 1957-58, which killed about 2 million worldwide, and the Hong Kong flu, which I have mentioned.  Vaccines became available in the 1960s, and supportive medical care and hygeine have improved exponentially over the last century, but the main reason that so may died from the Spanish flu is that it was a bird flu.  This explains why planning for a potential bird flu pandemic is taking such a priority with world governments at the moment.  The WHO website has at least one up -date daily on the current status of H5N1.  It is probably a bigger world threat than terrorism and therefore more worthy of a fridge magnet. 

The H5N1 strain does not seem to have developed the ability to jump from person to person as yet, but suspicions are that it is getting very close.  Once we have been able to isolate a mutant of the strain that has this ability, we will be racing to develop a vaccine.  This will take up to three months at the most accelerated rate, so that will be the critical period for avoiding getting infected.   If it does eventuate it will make SARS look like a small controlled exercise in disease control, which in retrospect it probably was, but it still cost the world economy $60 billion and caused 600 deaths.  The problem is people tend to shrug this off, and  complacently lump it in the same category of false alarms as the 2000 IT fears.  Or dismiss it as being a way for  people to make money out of  generating fear.

I attend regular updates on bird flu, as I am an advisor on preparedness to several companies.   Every time I leave one, I feel like going home and stockpiling baked beans, face masks and Tamiflu.  After a few days, I begin to relax again and feel reassured that the predicted likelihood of a pandemic in the next two years is currently only 10%, which viewed optimistically is not too bad. However, the WHO estimated it to be 1% just three years ago.

H5N1 is carried inside birds’ intestines and is distributed to the environment via bird faeces.  Migratory birds infected with the virus can therefore potentially spread the virus to any of the countries they visit.  Wild birds rarely die of the disease, but it has a high mortality amongst domestic birds.  A sick bird sheds the virus in its faeces, feathers, mucous and saliva.  Virus is present in its blood and flesh for a number of hours after its death.  Thorough cooking destroys it.  People who have close contact with sick birds are most at risk of infection, by faecal or saliva contamination or by eating improperly cooked flesh.  People who tend to live in close contact with poultry are generally those whom are most dependent on them for survival and so may be reluctant to report sick birds or family illness to the authorities, as this will result in wholesale slaughter.  And every time there is a ‘scare’ , such as the outbreak amongst poultry in England a few months ago, the sale of poultry plummets

The worrying thing about H5N1 is that it has a predilection for healthy young adults.  It has a long incubation period (up to ten days), and has about a 50% fatality rate.  Its symptoms are similar to the regular 'flu, but it tends to cause serious complications such as pneumonias, encephalitis, pericarditis and acute respiratory distress.

If a pandemic does occur, with say up to 40 or 50% of our adult workers being affected, the scenario being painted is bleak.  Hospitals full to overflowing, limited emergency services, no travel beyond one’s immediate vicinity, schools and businesses closed indefinitely, petrol rationing and no public transport.  Time to get to love baked beans.

The Australian Government is actually at the forefront of pandemic planning.  We have a Federal Government Action Plan for Pandemic Influenza and each state has it’s own plan, and these are being continually refined.  We have been stockpiling anti-viral medications for the past two years (Relenza and Tamiflu).  These are not a preventative, but if taken early enough in the infection can help to abort the infection or shorten the course.  They are not 100% effective and are a generic anti 'flu viral, not specific to H5N1, but are about the best antidote we have at the moment.  Only people in key front line positions will be issued with the medication, but individuals can obtain their own supplies on prescription.  There was a eight months wait to obtain it about 18 months ago, but now supples are readily available, but at about $80, it is not an option for most people to keep in their cupboard ‘just in case’.  (Confession:I have two lots in the sock drawer).

There is a little bit of evidence emerging that having the ordinary 'flu vaccine may confer some cross-immunity to  H5N1. However, the  most important thing that everyone can do is to get into the habit of  washing their hands, avoiding coughing and sneezing in public and throwing away their handkerchiefs.