Research from Harvard Medical School reveals how western equine encephalitis (WEEV) has evolved, losing its ability to infect humans due to changes in its spike proteins, which now fail to target human receptors but can still infect birds
in past outbreaks, hundreds of humans got sick and about 15 percent died.
it has to do with the ability of their spike protein to latch onto cells.
The team observed that the strains circulating during the years of frequent outbreaks could use multiple receptors that are expressed on brain cells of humans and horses, including proteins known as PCDH10 and VLDLR. Although the virus still circulates between birds, mosquitoes, and other animals, the most recent outbreak in the United States in humans was in 1987, according to the Centers for Disease Control and Prevention. Since then, there have been only five cases identified in the United States.
By contrast, when the researchers tested more recently isolated strains recovered from mosquitos in California in 2005, they found that the viral spike protein failed to recognize the human receptors, but could still interact with similar proteins found in birds.
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