Malaria news

Artemisia annua

Mostly news to me, rather than news per se:

1. Glaxo releases potential malaria cures to public researchers.
Reported a few months ago, but done as promised a couple of weeks back. Go here to pick one of 13500 compounds with anti-falciparum activity, screened from GSK’s library of 2 million chemicals with medicinal potential, and develop it into a lifesaving anti-malarial drug.

On the face of it this seems a little strange- who’d ever heard of big pharma passing up an opportunity to make money? However the revenue stream from malarial hotspots in sub-Saharan Africa was never going to be huge anyway; with efforts to control malaria in South America and Asia starting to bear fruit, presumably the company is looking ahead and realising that the payoff in “corporate social responsibility” kudos might be more valuable than the limited monetary return from developing the drugs themselves. A good thing, whatever the motives.

2. The problem with western Cambodia.
It was World Malaria Day last month. Various events marked the occasion, including this seminar at the London School of Hygiene and Tropical Medicine, which focussed on the current state of play with anti-malarial drugs. Slide shows and podcasts available via the link.

A big worry is the development of falciparum resistance to artemisinin in western Cambodia, and one of the slide shows suggests why this part of the world functions as a cradle of antimalarial resistance: political turmoil, a weak public health system, and a mobile population combined with a long history of stand-alone artemisinin use (it’s most effective in combination with other drugs- ACT), inadequate dosing, and fake/substandard drugs. Having travelled through Cambodia a few years back, all very believable— yet I’m sure it’s not the only malarious part of the world to which much of the above applies, and it’s still curious that chloroquine and mefloquine resistance also first appeared in the same region.

3. No link between climate change and malaria.
This has been controversial in the past, although I’d assumed that the debate had largely been settled— against the connection— already. Nevertheless, a new study puts the boot in. Gerthing et al quantify the mismatch between rising global temperatures over the last century and changes in malaria incidence, demonstrating that malaria has been in decline despite global warming. All this tells us is that temperature on its own is a poor predictor for malaria incidence, which isn’t altogether surprising- quite apart from all the other climatic influences (rainfall etc), the study confirms that economic development and stronger public health systems swamp any warming effect by an order of magnitude. Again, given that malaria was once widespread in temperate climates (see below) this is hardly news.

Chikungunya and West Nile virus are much more interesting in this context.

4. We used to have malaria here in the UK.
Definitely not news, even to me— but last month I found out that the last indigenous malaria case in Britain was as recent as 1953, when a London resident contracted vivax malaria from mosquitoes breeding in a nearby tree hole. This is much later than I’d thought (imported cases are still a big problem of course- between 1500 and 2000 per annum, of the more dangerous falciparum). Going a century or more further back, apparently the menfolk of the Essex marshes used to go to higher ground every year or two to obtain new wives, who might survive to produce a baby or two for their more-immune husbands before succumbing to the disease. We were all ‘third world’ back then.
(Sources here, here, and my dad.)

Further reading:
Excellent map showing world Plasmodium falciparum endemicity from Oxford’s malaria atlas project.


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