Researchers determine how mosquitoes survive dengue virus infection
Colorado State University researchers have discovered that mosquitoes that transmit deadly viruses such as dengue avoid becoming ill by mounting an immediate, potent immune response. Because their immune system does not eliminate the virus, however, they are able to pass it on to a new victim. In a study published February 13 in the open-access journal PLoS Pathogens, the researchers show that RNA interference – the mosquito immune response -- is initiated immediately after they ingest blood containing dengue virus, but the virus multiplies in the mosquitoes nevertheless. Dengue fever and dengue hemorrhagic fever are major global public health burdens, with up to 100 million cases occurring annually, yet no vaccines or specific preventative medicines are currently available. The Aedes aegypti mosquito transmits dengue virus. Determining how the virus evades the mosquito's defense is an important next step in research that aims to fight disease by interrupting the growth of dengue virus within the mosquito before it can be transmitted.
RNA interference is an evolutionarily ancient antiviral defense used by mosquitoes and other invertebrates to destroy the RNA of many invading arthropod-borne viruses. This team of researchers previously showed that ramping up the RNA interference response in mosquitoes prevented dengue infection, and now they show that temporarily impairing this immune response increased virus transmission.
The investigators analyzed RNA from adult mosquitoes, finding that both the trigger and initiator molecules for RNA interference were formed after infection, yet viral RNA could readily be detected in the same mosquitoes. They also measured infectious virus rates in the mosquitoes' saliva, which revealed levels whereby the mosquitoes could transmit the disease to humans.
These findings indicate that genetic manipulation of RNA interference could be a significant weapon in stopping dengue virus transmission by Aedes aegypti.
Source: Public Library of Science
Related
- New understanding of dengue virus points way to possible therapies for dengue feverWed, 22 Apr 2009, 13:45:22 EDT
- Visualizing virus replication in three dimensionsThu, 7 May 2009, 13:44:20 EDT
- Virginia Tech researchers discover how mosquitoes avoid succumbing to viruses they transmitMon, 1 Dec 2008, 17:36:33 EST
- Mosquito parasite may help fight dengue feverFri, 1 May 2009, 0:23:51 EDT
- Study shows paradoxical relationship between dengue hemorrhagic fever and its carrier mosquitoesThu, 17 Jul 2008, 11:43:09 EDT
Other sources
- Researchers determine how mosquitoes survive dengue virus infectionfrom PhysorgFri, 13 Feb 2009, 8:42:38 EST
- Researchers determine how mosquitoes survive dengue virus infectionfrom Science CentricFri, 13 Feb 2009, 4:21:49 EST
- Molecules help the immune system to detect cells infected with West Nile virusfrom Biology News NetTue, 10 Feb 2009, 9:57:31 EST
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