Navigation Links
Mosquito study shows new, faster way West Nile can spread

Researchers at the University of Texas Medical Branch at Galveston (UTMB) have discovered a quick new way that mosquitoes can pass West Nile virus to each other. The new study challenges fundamental assumptions about the virus' transmission cycle and may help explain why it spread so rapidly across North America despite experts' predictions that it would progress more slowly or even die out.

In the conventional understanding of West Nile transmission, mosquitoes acquire the virus when they bite birds with high levels of virus (or "high viremia.") in their blood. Those levels are reached several days after the birds are initially infected by other mosquitoes. But experiments at UTMB show that when infected and uninfected mosquitoes feed simultaneously on previously uninfected laboratory mice, the virus can pass from mosquito to mosquito within an hour.

"We were amazed to see that it could happen," said UTMB associate professor Stephen Higgs, lead author of a paper on the discovery that will be published online in the Proceedings of the National Academy of Sciences the week of June 6. "It is basically a brand-new component of the virus' life cycle."

In the paper, Higgs and his co-authors--UTMB graduate student Bradley S. Schneider, senior research associate Dana Vanlandingham, research assistant Kimberly A. Klingler and Ernest A. Gould of the United Kingdom's Centre for Ecology and Hydrology--note that although such "non-viremic transmission" (that is, transmission before virus can be detected in the blood) has been observed in cases involving viruses transmitted by ticks, it has never before been documented in a virus carried by mosquitoes.

To determine whether West Nile virus could be transmitted non-viremically, the researchers placed an anesthetized, uninfected lab mouse on a mesh-topped container holding infected "donor" mosquitoes, which fed on the mouse through the mesh. Five minutes later, they moved a second mesh-topped containe r in position so that its uninfected "recipient" mosquitoes could feed on the same mouse, allowing the simultaneous feeding by infected and uninfected mosquitoes to continue for an hour. In repeated experiments, tests revealed that between 2 and 6 percent of the recipient mosquitoes acquired the virus. In one trial, a single bite from a donor mosquito was sufficient to infect two out of 87 recipient mosquitoes.

The discovery calls into question the current conception of mosquito transmission of West Nile virus and possibly other viruses such as the one that causes dengue fever. According to that theory, many vertebrates were considered to be "dead-end hosts" that did not pass along the virus. Only birds, which develop much higher levels of the West Nile virus in their blood, were thought capable of passing it on to uninfected mosquitoes.

"None of the models that have attempted to predict the spread of West Nile virus take into account the possibility that mammals such as horses may be involved in the proliferation of this virus. Direct transfer of virus from the infected mosquitoes that initially feed on them to others that feed on them afterwards, could significantly accelerate the spread of the disease," Higgs said. "Instead of only birds infecting mosquitoes, all sorts of animals may be involved, and transmission could be happening much faster because you don't have to wait for a high viremia."


Source:University of Texas Medical Branch at Galveston

Related biology news :

1. Mosquitoes are more attracted to individuals infected with malaria
2. Mosquito spray increases toxicity of pyrethroids in creek, study finds
3. Mosquito genes explain response to climate change
4. Mosquito repellents that emit high-pitched sounds dont prevent bites
5. Bioartificial kidney under study at MCG
6. W.M. Keck Foundation funds study of friendly microbes
7. Yellowstone microbes fueled by hydrogen, according to U. of Colorado study
8. Genome-wide mouse study yields link to human leukemia
9. Clam embryo study shows pollutant mixture adversely affects nerve cell development
10. New imaging method gives early indication if brain cancer therapy is effective, U-M study shows
11. Same mutation aided evolution in many fish species, Stanford study finds
Post Your Comments:

(Date:11/18/2015)... New York , November 18, 2015 ... Market Research has published a new market report titled ... Growth, Trends, and Forecast, 2015 - 2021. According to the ... in 2014 and is anticipated to reach US$29.1 bn ... to 2021. North America ...
(Date:11/17/2015)... LIVERMORE, Calif. , Nov. 17, 2015  Vigilant ... has joined its Board of Directors. ... Vigilant,s Board after recently retiring from the partnership at ... owning 107 companies with over $140 Billion in revenue.  ... performance improvement across all the TPG companies, from 1997 ...
(Date:11/12/2015)... , Nov. 12, 2015  A golden retriever ... Duchenne muscular dystrophy (DMD) has provided a new lead ... Children,s Hospital, the Broad Institute of MIT and Harvard ... Brazil . Cell, pinpoints ... dogs "escape" the disease,s effects. The Boston Children,s lab ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... BETHESDA, Md. , Nov. 30, 2015  Northwest ... biotechnology company developing DCVax® personalized immune therapies for solid ... to adding an additional independent director, and the Company ... investigation of allegations in a recent anonymous internet report ... on both initiatives. Linda Powers stated, ...
(Date:11/27/2015)... , ... November 27, 2015 , ... ... that includes over 2,000 technical presentations offered in symposia, oral sessions, workshops, ... applied spectroscopy, covers a wide range of applications such as, but not limited ...
(Date:11/25/2015)... , Nov. 25, 2015  PharmAthene, Inc. (NYSE ... has adopted a stockholder rights plan (Rights Plan) in ... operating loss carryforwards (NOLs) under Section 382 of the ... --> PharmAthene,s use of its NOLs could ... change" as defined in Section 382 of the Code. ...
(Date:11/25/2015)... 25, 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS; ... and prospects remain fundamentally strong and highlights the ... recently received DSMB recommendation to continue the ZoptEC ... of the final interim efficacy and safety data ... in men with heavily pretreated castration- and Taxane-resistant ...
Breaking Biology Technology: