Navigation Links
Geneticists at the American Museum of Natural History trace the evolution of St. Louis encephalitis
Date:5/15/2008

Before West Nile virus arrived in this country, we had (and still have) a home-grown relative of this pathogen. An epidemic of unknown origin exploded around St. Louis, Missouri in the autumn of 1933, a disease that is now known to be transmitted by mosquitoes from birds to people. Now, a new analysis of the genome of St. Louis encephalitis completed at the Sackler Institute for Comparative Genomics at the American Museum of Natural History (AMNH) is shedding light on the evolution of this virus.

Under the direction of Susan Perkins, Assistant Curator of Microbial Genomics, postdoctoral fellows Gregory Baillie, Sergios-Orestis Kolokotronis, and Eric Waltari sequenced the entire genetic code of 23 strains of the virus that cause St. Louis encephalitis, all from the genus Flavivirus. Previous research had found that recombination (the cutting and pasting of strands of genetic material, in this case RNA) explained the evolution of this virus, but these studies sequenced just a single gene of the virus. Because the whole-genome approach turned a microscope on the entire set of instructions for St. Louis encephalitis, the AMNH researchers were able to determine that a single mutation in the coding for an envelope protein rather than recombination most likely caused changes that made the virus pathogenic to humans. Recombination is important for disease; it makes novel proteins or genes that the immune system has never seen before, explains Perkins. But in this case, it was population dynamics combined with slight changes in the form of point mutations that have been important in the evolution of this virus.

Genetic analysis also allowed Perkins and colleagues to trace the evolutionary path of the Flavivirus virus. They determined that the older, less derived strains, or more ancestral strains, are from South America. The North American and Haitian strains were passed from common bird hosts such as finches, robins, blue jays, and doves into humans by the Culex mosquito after the virus exploded into a new continent. To time this event, researchers again turned to the genomic code: by determining the rate of mutation in the virus, Perkins found that the division between the South and North American strains happened about 116 years ago. St. Louis encephalitis is a perfect storm between infected bird hosts coming into a new area and the mosquito vectors transferring the virus to humans, says Perkins. It is the North American version of West Nile.

St. Louis encephalitis is currently found throughout the United States, and, according to the Centers for Disease Control, there were 4,651 cases between 1964 and 2005. Symptoms range from a mild headache to high fever and tremors. Mortality is between 5 and 30% and is higher among the elderly.


'/>"/>

Contact: Kristin Phillips
kphillips@amnh.org
212-496-3419
American Museum of Natural History
Source:Eurekalert

Related medicine news :

1. Destruct triggers may be jammed in tumor cells, UF geneticists say
2. Many Older Americans Have Active Sex Lives
3. Despite grumbling, most Americans say they are happy at work
4. Record Number of Americans Lack Health Insurance
5. Longaberger Expands Horizon of Hope Campaign to Build Support for American Cancer Societys Breast Cancer Initiatives
6. AUDIO from Medialink and Pfizer: Number of Uninsured Americans Grows to 47 Million
7. New Survey Shows Americans are Still Concerned About Food Safety, Yet Still Not Smart About What They Like to Eat
8. Novo Nordisk Appoints New Leader of North American Business
9. Amid Improving Life Expectancy Rates, Risk of Premature Death is Still Significant for Americans, New Study Shows
10. Primary biliary cirrhosis more severe in African-American and Hispanic patients
11. AOA President Calls on Congress to Reauthorize SCHIP and Take Action to Ensure Health Care Coverage for All Americans
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... June 26, 2016 , ... On June 10-11, 2016, A ... 2016 Cereal Festival and World’s Longest Breakfast Table in Battle Creek, MI, where the ... history as home to some of the world’s leading providers of cereal and other ...
(Date:6/26/2016)... ... June 26, 2016 , ... Many women ... diagnosed with endometriosis. These women need a treatment plan to not only alleviate ... that can help for preservation of fertility and ultimately achieving a pregnancy. The ...
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... "With 30 ... their specific project," said Christina Austin - CEO of Pixel Film Studios. , ... and all within Final Cut Pro X . Simply select a ProHand generator ...
(Date:6/25/2016)... ... June 25, 2016 , ... On Friday, June 10, Van Mitchell, ... at Work award to iHire in recognition of their exemplary accomplishments in worksite health ... annual Maryland Workplace Health & Wellness Symposium at the BWI Marriott in Linthicum Heights. ...
(Date:6/24/2016)... , ... June 24, 2016 , ... June 19, 2016 ... dangers associated with chronic pain and the benefits of holistic treatments, Serenity Recovery ... are suffering with Sickle Cell Disease. , Sickle Cell Disease (SCD) is a disorder ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... , June 23, 2016  Guerbet announced today that ... Supplier Horizon Award . One of ... was recognized for its support of Premier members through ... clinical excellence, and commitment to lower costs. ... this recognition of our outstanding customer service from Premier," ...
(Date:6/23/2016)... , June 23, 2016 Research ... "Surgical Procedure Volumes: Global Analysis (United States, China, Japan, ... report to their offering. ... tool for healthcare business planners, provides surgical procedure volume ... surgery trends with an in-depth analysis of growth drivers ...
(Date:6/23/2016)... -- The Biotechnology industry might still be ... opportunities to investors. Stock-Callers.com assesses the recent performances of ... XON ), Vertex Pharmaceuticals Inc. (NASDAQ: ... ), and Regeneron Pharmaceuticals Inc. (NASDAQ: REGN ... complimentary trade alerts at: http://stock-callers.com/registration ...
Breaking Medicine Technology: