Navigation Links
Geneticists at the American Museum of Natural History trace the evolution of St. Louis encephalitis

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
American Museum of Natural History

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:
(Date:12/1/2015)... ... December 01, 2015 , ... Califia Farms , one ... its iconic bottle has won top honors in Beverage World Magazine’s Global Packaging Design ... announced that it has been selected as a 2015 U.S.A. Taste Champion in the ...
(Date:12/1/2015)... ... December 01, 2015 , ... December 1, 2015—Since the start ... scientific research and discoveries, leading us to better understand the disease’s behavior. Globally, ... affected by HIV/AIDS. Mediaplanet’s cross-platform edition of “World AIDS Day” provides insight on ...
(Date:12/1/2015)... ... December 01, 2015 , ... ... optimization of adjunctive imaging is the focus of numerous abstracts accepted for presentation ... 29-December 4, 2015. Nine abstracts highlight the use of Volpara Solutions’ quantitative ...
(Date:12/1/2015)... WA (PRWEB) , ... December 01, 2015 , ... ... today that it has been selected as a finalist in this year’s Fierce ... and FierceMobileHealthcare. Next IT Healthcare was recognized as a finalist in the category ...
(Date:12/1/2015)... ... December 01, 2015 , ... XTC Semifinals 2016 - ... to head to Las Vegas for CES 2016, the world’s largest Consumer Electronic Show, ... Technology Association Gary Shapiro, Founding Partner of Pacific Investments Veronica Serra, and venture capitalist ...
Breaking Medicine News(10 mins):
(Date:12/1/2015)... BANGALORE, India and PITTSBURGH ... TASE: MYL) today announced that it expects to be ... developing country markets funded by international donors, TLE400 (Tenofovir ... Efavirenz 400 mg) for $99 per patient, per year. ... to develop TLE400. The significantly reduced price could generate ...
(Date:12/1/2015)... , Dec. 1, 2015 Breg, Inc ... services, announced today that it has been awarded three ... Members served by Novation will have access to improved ... bracing products and soft goods dedicated to advancing orthopedic ... The aging U.S. population, rising prevalence of chronic ...
(Date:12/1/2015)... N.J. , Dec. 1, 2015 ... against HIV/AIDS, Johnson & Johnson (NYSE: JNJ ... its Janssen Pharmaceutical Companies to significantly reduce the ... who make up 74 percent of new HIV ... Announced on World AIDS Day, these new initiatives ...
Breaking Medicine Technology: