Researchers have decoded the genomes of two different malaria parasites that plague people in Southeast Asia and South America, and say the new information will boost efforts to find a vaccine for the mosquito-borne disease. The work builds on the sequencing of the first malaria genome six years ago, when scientists tackled the most deadly malaria parasite, Plasmodium falciparum, which is endemic in Africa. By comparing the genetics of Plasmodium falciparum to that of the newly sequenced species, P. knowlesi and P. vivax, the two teams have begun to identify the different mechanisms by which each species maximizes its chances of evading the host immune system [The Scientist].
P. vivax is the main cause of malaria in Latin America and Southeast Asia, and although it’s rarely deadly researchers say it still causes plenty of misery. It’s also challenging to eradicate because it can lie dormant in the liver for months. “It makes people very sick,” says lead researcher Jane Carlton…. “It can come out of the liver weeks or months after the initial mosquito bite. That makes it a very serious risk to human health.” Vivax malaria is so debilitating that sufferers, most of whom are poor, can’t support themselves or their families. “Vivax is one of the stealth reasons that poor people can’t escape poverty,” says [tropical disease expert] Peter Hotez [USA Today].
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A warmer world will also be a sicklier place for both animals and humans, according to a new report from the Wildlife Conservation Society (WCS). Dubbed the “deadly dozen,” sicknesses such as Lyme disease, yellow fever, plague, and avian influenza, or bird flu, may skyrocket as global shifts in temperature and precipitation transform ecosystems. Babesia, cholera, Ebola, intestinal and external parasites, red tides, Rift Valley fever, sleeping sickness and tuberculosis round out the list [National Geographic News].
The report spells out how global warming is changing the ranges and habitats of animals that carry these infectious diseases, bringing the ticks that transmit Lyme disease and the mosquitoes that carry yellow fever and Rift Valley fever into contact with new human populations. “We’ve seen Lyme disease work its way up from the US into Canada, and West Nile fever as well,” said William Karesh, director of WCS’s global health programmes. “Basically what you have now are fewer frozen nights in this region, and that allows the ticks and mosquitoes that carry these diseases to survive further north” [BBC News].
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Finally, the U.S. Department of Defense is working on a bomb that even peaceniks can get behind — a bug bomb!
Motivated by the need to protect soldiers in the field from biting pests, the Defense Department teamed up with the Department of Agriculture to search for a longer-lasting and more effective insect repellent. “That was the principal motivation, the usability for the military,” says USDA investigator Ulrich Bernier. “You don’t want your soldiers reapplying every 15 to 20 minutes” [Science News].
Researchers have already identified several chemical compounds that seem far more effective than the current standard-bearer, DEET. In one test, a cloth soaked with a particularly promising compound repelled mosquitoes for 73 days, while DEET-soaked cloth lasted only 13 days.
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