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)... ... October 13, 2017 , ... Dickinson Insurance and ... and financial preparation services, is providing an update on a charitable event that ... City Rescue is a locally recognized nonprofit that provides shelter and care for ...
(Date:10/13/2017)... ... , ... PurhealthRX , a leading Health and Nutrition Company, is announcing ... full spectrum CBD oil will revolutionize the rapidly growing CBD market by reducing the ... incorporated into liquid products, while reducing costs to end users. , The team of ...
(Date:10/13/2017)... ... October 13, 2017 , ... The Visiting Nurse Association (VNA) of ... collection of specialty vendors and unique items from across the nation, this holiday-themed event ... wellness services offered by the VNA. The boutique will be open Saturday, November ...
(Date:10/13/2017)... ... October 13, 2017 , ... ... Agile Software Development, has been awarded a contract by the Center for Medicare ... (BPA) aims to accelerate the enterprise use of Agile methodologies in a consistent ...
(Date:10/12/2017)... , ... October 12, 2017 , ... Planet Fitness, one ... U.S., announced today its plans to open a flagship location in Covington, LA at ... former Rooms To Go store next to Office Depot in the Holiday Square shopping ...
Breaking Medicine News(10 mins):
(Date:10/12/2017)... Divoti USA will engrave and process all non-coated ... latest FDA requirements, which stipulates new criteria regarding medical device manufacture ... Medical ID jewelry such as Medical ID Bracelets, can rest assured ... of the new FDA requirements . ... Divoti offers this dark mark fiber laser engraving process ...
(Date:10/11/2017)...  Caris Life Sciences ® , a leading innovator ... precision medicine, today announced that St. Jude Medical Center,s ... (POA) as its 17 th member. Through participation ... Cancer Institute will help develop standards of care and ... making cancer treatment more precise and effective. ...
(Date:10/10/2017)... received FDA 510(k) clearance in May 2017 for its highly anticipated ... for endoscopy environments. An innovative secondary monitor solution, ZeroWire Mobile ... the improvement of patient outcomes, procedural efficiency, and the lowering of ... ... By ...
Breaking Medicine Technology: