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Australian scientists breed mosquitoes that resist dengue fever virus

Skeeters help fight disease

Australian scientists have made a promising advance for controlling dengue fever, a tropical disease spread by mosquito bites that sickens 50 million people a year in tropical and subtropical regions. Scientists infected Aedes aegypti mosquitoes, the chief carriers of the dengue virus, with a bacteria that made them resistant to the virus. Offspring of resistant females are also resistant. Offspring of ordinary females that mate with a resistant male do not survive. Scientists released more than 140,000 resistant mosquitoes in two isolated communities. Two months later, they found that resistant mosquitoes made up 90 percent to 100 percent of the wild population. The research was published in Thursday's issue of the journal Nature.

Weather lowers sea levels

The global sea level this summer is a quarter of an inch lower than last summer, in contrast to the gradual rise the ocean has experienced in recent years. The change stems from two strong weather cycles over the Pacific Ocean — El Niño and La Niña — which shifted precipitation patterns, according to scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif. The two cycles brought heavy rains to Brazil and the Amazon region, along with drought to the southern United States. Strong evaporation at sea, which preceded the heavy rains, caused global sea levels to fall. Long-term, according to computer climate models, sea levels are expected to rise as melting glaciers and ice sheets in Greenland and Antarctica contribute to global sea levels.

Survival hope for rare croc

One of the world's rarest crocodile species has moved a little bit further from extinction with the hatching of 20 wild eggs plucked from a nest found in southern Laos. Experts believe there could be as few as 300 Siamese crocodiles remaining in the world's swamps, forests and rivers, so the discovery of the nest — the first found in the mountainous, jungle-clad country since 2008 — is a significant step in the rehabilitation of a species that was declared extinct in the wild in 1992. Since then, tiny populations have been discovered in remote corners of its range, which used to include most of Southeast Asia. The New York-based Wildlife Conservation Society is working to save the species in Laos.

Australian scientists breed mosquitoes that resist dengue fever virus 08/26/11 [Last modified: Friday, August 26, 2011 9:05pm]
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