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.
PLEASE ADD THIS LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.
CITATION: Sa´nchez-Vargas I, Scott JC, Poole-Smith BK, Franz AWE, Barbosa-Solomieu V, et al. (2009) Dengue Virus Type 2 Infections of Aedes aegypti Are Modulated by the Mosquito's RNA Interference Pathway. PLoS Pathog 5(2): e1000299. doi:10.1371/journal.ppat.1000299
This press release refers to an upcoming article in PLoS Pathogens. The release is provided by the article authors and their institution. Any opinions expressed in these releases or articles are the personal views of the journal staff and/or article contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the releases and articles and your use of such information.
About PLoS Pathogens
PLoS Pathogens (www.plospathogens.org) publishes outstanding original articles that significantly advance the understanding of pathogens and how they interact with their host organisms. All works published in PLoS Pathogens are open access. Everything is immediately available subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.