Malaria parasite 'changes state'4th December 2007
New research has shown how the malaria parasite behaves very differently in human hosts to its observed behaviour in the laboratory.
The mosquito-borne parasite, Plasmodium falciparum, even changes in contact with the different physiological circumstances of each individual it infects, according to researchers from Senegal and the United States.
The study, published in the journal Nature, screened patients at east Senegal's Vekingara Hospital, which lies in a region where malaria is strongly endemic.
They found through genetic analysis of the parasite in each blood sample from 43 children, that each human host had influenced the parasite's physiology, and possibly even its virulence.
Co-author Daouda Ndiaye, of the Le Dantec teaching hospital in Dakar, said the findings could provide a key to understanding why some people are so much more seriously affected by malaria than others.
The researchers described a previously unknown physiological diversity in the biology of malaria in a living organism, which was markedly different from how it has been seen in laboratory observations.
Ndiaye said the findings were a real advance in malaria research. Researchers had identified two new biological states of the Plasmodium falciparum parasite--from just 43 patients.
The two new states were starving, and stressed. Laboratory cultures have previously only observed parasites which were actively growing.
This has led to a whole set of assumptions being based on those observations, which may be of limited applicability in living hosts, according to co-author Elizabeth Winzeler of the Genomics Institute of the Novartis Research Foundation in California.
The study showed that such assumptions might well be faulty, and that the physiology of parasites in people might be very different from their state in a laboratory test tube, Winzeler said.
The problem could point to why certain drugs do not work as they are expected to do during treatment of malaria.
The study will aid malaria drug development and improves the chance of developing a malaria vaccine, and could result in more effective drug combinations which target both physiological states [in human hosts and laboratory conditions] simultaneously, Winzeler said.
Better drug combinations would reduce the threat of drug resistance emerging.
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Title: Malaria parasite 'changes state'
Author: Luisetta Mudie
Article Id: 4968
Date Added: 4th Dec 2007