Talk 3: Winning and Losing the Fight Against Infectious Diseases

September 25, 2013 § Leave a comment

Talk given by Professor Christopher Dye, World Health Organisation, 16th September 2013

I queued for this one, down the steps of the Royal Society and out along Carlton Terrace, watching gentlemen on their way to gentlemen’s clubs like the Carlton and Whites. Smart area. The Royal Society is pretty nice. Turns out lots of people want to hear about infectious diseases. While we waited for the Professor, people chatted.

“What field are you in?”

“I was in chemical engineering but I’m retired now. And you?”

“I work on malaria.”

(Obviously, this wasn’t me.)

Professor Dye, younger than I had imagined, said he was going to give us “a personal view of infectious diseases.” Apparently, Hollywood has much to answer for in terms of how we understand, or misunderstand, the nature of infection – we saw some pictures from Contagion, which I don’t think Prof Dye really enjoyed.

Here are some more things I learned.

1. We should all be frightened of pandemics – H1N1, Spanish Flu, etc. – but most deaths from infectious diseases (IDs) are not caused by pandemics. Fifteen million people a year die from IDs that just inhabit their everyday lives – diarrhoea, HIV, TB, malaria, meningitis. About 20 pathogens account for nearly all deaths from IDs.

2. In the UK, death rates from IDs fell for three centuries from the early 18th Century. This is largely due to better sanitation, more food, and better public health – things like vaccinations. However, in recent years, death rates have finally plateaued at around 13 per 100. The downside is that there has been a steep rise in non-communicable diseases but, as Prof Dye pointed out, we do all have to die of something.

3. There is a link between infectious and non-infectious diseases. For example, being under-weight makes a person more susceptible to TB. In the West, we eat well so TB is not so prevalent. However, because we eat well, we develop diabetes. Having diabetes makes a person more susceptible to TB. Tricky.

Public health campaigns in the 1920s tried to halt the spread of TB.

3. In the developing world, not surprisingly the rates are the other way round.

4. The good news is that control of infectious diseases was one of the Millenium Goals and money spent on controlling IDs has risen from £5b in 1990 to £25b in 2010. However, since 2010 the rate of increase has declined. One reason for this is the growing importance of non communicable diseases.

5. Living in a city is both good and bad news. Since 2007, more of us have been living in urban areas than rural ones and in cities of over 500,000, infections really flourish. On the up side, infant mortality rates are substantially lower in cities than in the countryside, even for people living in slums.

6. It is probable that the 2003 SARS pandemic emerged from bats in South Asia. One in two people infected died. Researchers can follow its spread from five guests in the Metropole Hotel in Hong Kong to 206 other people. It is probable that SARS is no longer in the human population.

7. There is reason to worry about resistant to antibiotics – in the last 40 years, there have been no major developments. On the other hand, researchers don’t really understand why some diseases become resistant while others don’t. For example, syphilis has never become resistant to penicillin, so the case is not completely lost.

drug-resistant-tuberculos

8. Only two diseases have ever been officially eradicated, small pox and rinderpest, a disease in cattle. The major emphasis now is on eradicating polio, which persists in rumbling on in Africa and parts of Asia. Professor Dye asked Paddy Power for odds on eradicating polio and was given 4-1.

9. There are 2.4 billion people in the world without access to piped drinking water, and 1 billion without access to sanitation. Given that we have known how to do both since the 1850s, when James Bazelgette reclaimed the banks of the Thames in order to construct sewers (John Betjeman said, “Our nation stands for democracy and proper drains”), why have those billions had to wait for so long for clean water?

Bazelgette inspects his work.

10. We don’t really understand the connection between infectious diseases and genes. Why do only 1 in 10 people infected by tuberculosis develop the disease?

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