Posted on 10/30/2007 6:00:23 PM PDT by CutePuppy
Researchers could be a step closer to a cure for malaria after discovering people with blood group O are naturally protected from its most severe forms.
Edinburgh University has found blood type O people are significantly less likely to experience the most life-threatening effects of malaria.
It is hoped the discovery will help develop drugs which mimic the properties of red cells.
Red cells in O group blood prevent malaria worsening.
"We may be able to reduce the number of children dying from severe malaria in sub-Saharan Africa"
Dr Alex Rowe
Edinburgh University
Scientists at Edinburgh University and researchers in the US, Mali and Kenya studied African children and found that those with blood type O were two-thirds less likely to experience unrousable coma or life-threatening anaemia.
Both conditions are characteristic of severe malaria. Their findings are published in the journal PNAS.
In fatal malaria, it is often found that red blood cells which are infected by parasites block blood vessels which supply oxygen to the brain.
Malarial parasites arm the blood cell's surface with proteins which stick to blood vessel walls.
Malaria parasites
These proteins recruit healthy red blood cells to stick to the parasite, encasing the infected red blood cell inside a so-called rosette. It makes the blockage, and the disease, worse.
However, the team's latest findings suggest that group O red blood cells do not easily join rosettes as the cell's surface structure prevents it from sticking fully.
The researchers found that the process of rosetting is associated with severe malaria in all blood groups except O, and that rosettes are less well formed in group O red blood cells.
They suggest that reduced rosetting of malaria parasites is the reason why people with group O blood are less likely to suffer severe malaria.
It is estimated that malaria claims up to two million lives annually around the world.
Dr Alex Rowe, of Edinburgh University's School of Biological Sciences, said: "This discovery explains why some people are less likely to suffer from life-threatening malaria than others, and tells us that if we can develop a drug or a vaccine to reduce rosetting and mimic the effect of being blood group O, we may be able to reduce the number of children dying from severe malaria in sub-Saharan Africa."
The research was funded by the Wellcome Trust and the National Institutes of Health.
5.56mm
O blood type ping
Naive question...
so is blood type “O” enriched in the human population in the areas
subject to lots of mosquitos that carry malaria?
Of course, there’s the compounding factor that the disease has effects
that range over a spectrum...but I’m just curious if this has played
out over millions of years in a higher rate of type “O” in malaria-ridden areas.
DDT
Lucky me!
This guy is a voice in the wilderness. Your blood type determines most things. It’s good to be O, bad to be A.
It’s not a naive question at all, it’s a good one.
I don’t have the data or how they came to looking at this, but I would assume that, in part, it may have been a result of data mining process where they discovered higher than “normal” occurance of Type O in [previously] affected areas.
FTA: ... “researchers in the US, Mali and Kenya studied African children” ...
I would think that part of the future research might include the study of blood type binomial distribution and/or histogram in the [previously] affected areas. If medical data is available (which is unlikely) it would be interesting to see the blood type distribution changes over time in those areas.
True, and it does not care about blood type. Still, this discovery is very interesting, along the lines of [natural] immunization.
Blood type O is by far the most common blood type in humans.
'Indigenous' populations for the maps.
link.
This is for severe malaria. Type Os can still contract malaria; the odds that the malaria will put them into a coma or give them extreme anemia are just less than for the other blood groups.
I’ve read that in South America, almost everyone is A or O. B just disappeared from the population.
Type AB makes you immune to cholera. I wonder if that is the only reason types A and B are still around.
Shoud we let natural selection do its work with malaria or should we override it with new cures? Always an interesting question.
Are the cures allowing weaker genetic lines to survive?
Or, maybe there’s something to this thing about acquired traits actually being passed on that allow or even help weaker genetic lines get stronger.
Research was done mostly in Mali and Kenya - per your maps, it was in the areas / continent with 70 to 90 percent of population with Type O. It just might explain why malaria did not wipe out more of a population of Africa, while being a serious problem there, since they didn't widely use DDT in Kenya or Mali, as far as I know (at least not until recently).
It also might help explain the postulate by VOA in post #4.
From Malaria Site, here are the maps of the risk of malaria for North/Central and South Americas, where blood Type 0 is predominant (90-100%) :
I’ve got O+ and have had Malaria twice. Wasn’t VERY bad either time, most like the intestinal flu.
For blood type/disease, the advent of modern medicine has kept people alive who would have otherwise been killed. And that is a good thing. As for blood type and genetic 'defects' (or disadvantages), gene therapy or other genetic alteration could work on that.
Also, according to maps in post #11, most of us in Americas are Type O, so we are mostly "good"...
Mike, thanks for the ping.
Annecdotal evidence but not really supportive: My husband and I have O+ blood. We have only suffered from the tersiana and tropica forms of the disease, never the cerebral and thankfully not the “blackwater” form.
Perhaps we haven’t yet been exposed to those forms.
I am not sure what the blood types of the indigenous population are. I do know that the government will not let a white person donate to a local. We supposedly don’t have compatible types.
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