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Friday, 20 March 2015

Why a return of scarlet fever?

Medical authorities in England are reporting a sharp increase in scarlet fever. This disease, which tends to affect children rather than adults, was once common. Many great-grandparents can recall being admitted to “fever hospitals” when they contracted it in the 1930s and 40s. These were special isolation units set up to nurse and isolate children who were suffering from infectious diseases.
It starts with a sore throat caused by a bacterium. The infection then becomes more widespread in the body, causing the rash of scarlet fever. Scarlet fever is potentially dangerous because it can develop into rheumatic fever, a complication that can infect and permanently damage heart valves. It was named “rheumatic” because inflamed joints are often involved. In my copy of the John Bull Family Doctor (first owned Ivor J Rees, in 1933) the page that describes how to nurse a sufferer is the only one with the corner turned down. Aspirin, for the joint pain, was the only medicine available.
Both my parents had rheumatic fever and my father’s heart was so badly damaged that he died at 34. I was only four at the time so I have few memories of him. My mother-in-law also had rheumatic fever, which caused heart problems throughout her life. She was admitted to hospital with rheumatic fever as a small girl (“I couldn’t understand why my mother had left me there.”) and, while there, she contracted diphtheria as well.
In the 1950s and 60s rates of scarlet fever declined sharply, probably because antibiotics became available as a fast and effective treatment for infected throats.
People have been asking why there is a resurgence of this disease, which has been so rare in recent generations. Several possibilities occur to me:
GPs are, quite rightly, trying not to prescribe antibiotics for sore throats, saying things like "come back in 7 days if it’s not better". Most sore throats are viral and do clear up. But some bacterial sore throats might be missed as an unintended consequence of this change in GP behavior and could, in a week, develop into scarlet fever.
Children are getting the antibiotics but the bacteria are becoming resistant. The prescription does not work and the throat develops into scarlet fever.
In some areas GP services are under such pressure that parents may be having difficulty getting an appointment. Again a delay in seeing a doctor may result in a bad throat becoming scarlet fever.
Another factor may be an increase in poverty. Other bacterial diseases, notably TB, were steadily declining in the years before antibiotics were discovered. There is a link between TB and overcrowded, impoverished living conditions. Could the same apply to Scarlet Fever? For instance it may be that (due to changes to housing benefit) there is an increase in families living in bad quality, overcrowded housing. It could also be that there is an increase in families who don't have enough to eat (indicated by the growth of food banks). I remember a few years ago being quite shocked to read that rheumatic fever was not rare in New Zealand. The incidence is higher in Maoris and Pacific Islanders. These groups tend to suffer significantly more poverty and overcrowding, and worse health, than the white population. I wondered if the same picture might be found in Australia, where indigenous ethnic groups do even worse than in New Zealand and, blow me down, I was right.
It is possible that several factors are coming together to cause an upsurge in this unpleasant and potentially dangerous disease. If the incidence continues to rise, UK health officials could do worse than look to Australia and New Zealand to see what could be learned.

Tuesday, 10 March 2015

Why's my virus lingering?

In my previous post, written while in the gloomy grip of a viral illness I was eagerly awaiting the arrival of legions of lymphocytes and antibodies, all perfectly honed to deal with this particular virus. I am now at the “lingering” phase.
Disabling lassitude and gloom receded as my innate immune system retired from the field. My energy levels are nearly recovered but my sinuses are sensitive and my nasal passages and larynx are still decidedly damp.  And everyone I speak to who has had a winter virus seems to have the same complaint – it’s gone, in the main, but not yet forgotten. “It’s lingering” seems to be the common theme.
We should nod with respect to the complex interaction that helps us move into phase two. The innate system obviously “knows” when it can let up with those darn cytokines and let the adaptive system do its work. Hence the big leap forward after 4-7 days.
But why does the miraculous and ultimately effective adaptive immune system take so long to finally get rid of coughs and catarrh?
We have to imagine a numbers game. Viruses “breed” by invading cells and using material in those cells to make a new batch of viruses. The numbers produced are very, very large. Every time an infected cell bursts open they are releasing many thousands of virus particles with the potential to infect nearby cells.

The lymphocytes and antibodies are numerous too, but as they start to do their work, the virus production line is well-established so there is a massive amount of catching up to be done. It’s a bit like weeding a large patch of land on which the weeds are already producing seeds and the seedlings are sprouting almost as fast as the gardener can work. In the end the adaptive immune system always eliminates the last few viral particles. And the bonus prize is that it remembers the unique signature of the virus, so if you encounter it again next year it will be despatched without causing a single symptom.

I have just read a long and detailed account of the interaction between the immune system and the virus during flu (see link, below). As I sit here coughing I am slightly cheered by the thought that the sticky cough-inducing mucus in my larynx is the result of the wholesale death of infected cells.

This little episode has reminded me that influenza and other flu-like illnesses do nothing to enhance life. They can wipe out a week, or three while you wait for them to go. At least when it comes to influenza itself it’s easy to reduce the chances of picking it up by having a flu jab every autumn. It won’t prevent every possible virus – but it increases your chances of having a flu-free winter, and that’s worth having.