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:10/13/2017)... ... ... Yisrayl Hawkins, Pastor and Overseer at The House of Yahweh, has released a ... books in the Holy Scriptures, Revelation. The Book of Revelation paints a picture of ... have tossed it off as mere rubbish, but Yisrayl Hawkins says that is because ...
(Date:10/13/2017)... ... 2017 , ... “America On The Brink”: the Christian history of the United ... the creation of published author, William Nowers. Captain Nowers and his wife, Millie, ... spent thirty years in the Navy. Following his career as a naval aviator ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... the demand of today’s consumer and regulatory authorities worldwide. From Children’s to Adults ... tested to meet the highest standard. , These products are also: Gluten ...
(Date:10/12/2017)... ... October 12, 2017 , ... Information about the ... to develop to enable prevention of a major side effect of chemotherapy in ... in pediatric patients. For cisplatin, hearing loss is FDA listed on-label as a ...
(Date:10/12/2017)... FL (PRWEB) , ... October 12, 2017 , ... On ... holding a treadmill relay – Miles by Moonlight to raise money for the American ... $300 or more. , Teams will work together to keep their treadmills moving ...
Breaking Medicine News(10 mins):
(Date:9/28/2017)... , Sept. 28, 2017 Hill-Rom Holdings, Inc. ... earnings conference call and webcast on Friday, November 3, ... (EDT) and ending at approximately 8:30 a.m. (CDT) / ... the company,s 2017 financial performance and guidance for 2018, ... initiatives to enhance operational performance, and long-range financial outlook ...
(Date:9/25/2017)...  EpiVax, Inc., a leader in the fields ... announced the launch of EpiVax Oncology Inc., a ... cancer vaccines. EpiVax has provided $500,000 in seed ... technologies to the new precision immunotherapy venture. Gad ... as Chief Executive Officer. Gad brings over 25 ...
(Date:9/19/2017)... , Sept. 19, 2017   ZirMed Inc ., ... analytics, today announced that it has been ranked #1 by ... Black Book™ Rankings 2017 User Survey. ZirMed was recognized ... for large hospitals and medical centers over 200 beds and ... Book,s healthcare technology user survey history. ...
Breaking Medicine Technology: