Chitchat Asian strain of Zika

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An honorable member of the Coffee Shop Has Just Posted the Following:

I pulled this off the net.

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Source: http://www.nytimes.com/interactive/2...ika-virus.html

The virus is thought to have reached Asia from Africa at least 50 years ago. While it may have caused spikes in microcephaly as it first spread, there was no testing to pin down which of many possible causes was to blame.

In 2007, a Southeast Asian strain of the Zika virus began leapfrogging the South Pacific, sparking rapid outbreaks on islands where no one had immunity to it. Because island populations are small, rare side effects did not occur often enough to be noticed. But in 2013, during an outbreak in French Polynesia, which has 270,000 residents, doctors confirmed 42 cases of Guillain-Barrê syndrome, which can cause paralysis. That was about eight times the normal number and the first hint that the Zika virus can attack the nervous system, which includes the brain.

French Polynesia is the only area outside Brazil to be affected by a Zika outbreak in which public health officials have identified an increase in the number of fetuses and babies with unusually small heads. There is “very high suspicion” of a link between the Zika virus and microcephaly in French Polynesia, said Dr. Didier Musso, an infectious disease specialist at the archipelago’s Institut Louis Malardé – though he said additional research was needed.

In November, French Polynesian officials took another look at an outbreak of the Zika virus that lasted from October 2013 to April 2014. They reported finding an unusual increase – from around one case annually to 17 cases in 2014-15 – of unborn babies developing “central nervous system malformations,” a classification that includes microcephaly.

There were no investigations at the time to determine whether the mothers were infected with the Zika virus during pregnancy. Four of the mothers were tested later, and the results indicated they may have been infected. Additional research is underway, Dr. Musso said.

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Source: https://www.sciencedaily.com/release...0901125057.htm

Scientists have revealed molecular differences between how the African and Asian strains of Zika virus infect neural progenitor cells. The results could provide insights into the Zika virus' recent emergence as a global health emergency, and also point to inhibitors of the protein p53 as potential leads for drugs that could protect brain cells from cell death.

Zika virus was first discovered in Uganda in the 1940s, and two distinct lineages of Zika diverged sometime in the second half of the 20th century: African and Asian. The strains currently circulating in the Western Hemisphere, which have been linked to microcephaly in infants and Guillain Barre syndrome in adults, are more closely related to the Asian lineage.

The research team catalogued and compared genes turned on and off by Asian and African strains of Zika virus, as well as dengue virus, in human neural progenitor cells. The authors describe dengue as inducing more robust changes in gene expression than either strain of Zika. Although they show that dengue can infect neural progenitor cells like Zika can, dengue infection does not stunt the cells' growth or lead to cell death.

"This shows that the differences between Zika and dengue are not at the level of being able to infect neural progenitors, but more about the harm Zika causes when it does infect those cells," says senior author Peng Jin, PhD, professor of human genetics at Emory University School of Medicine.

In comparison with African strains, infection by the Asian strain of Zika virus more potently affected the p53 gene and genes connected with cells' responses to viral infection, such as interferons. Both Zika strains were able to infect and cause cell death in neural progenitor cells.


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