Ebola virus does a total shutdown to hide before new strike

[cronus]

https://www.newscientist.com/article/20 ... sh-strike/

Ebola virus does a total shutdown to hide before a fresh strike

Ebola refuses to die. Affected West African countries have repeatedly stopped transmission of the virus, only for fresh outbreaks to appear, seemingly out of nowhere. The most recent outbreak was in Liberia, where a 10-year-old boy in Monrovia was diagnosed with Ebola earlier this month. He had no known exposure to the virus, and the World Health Organization suspects he caught it from a survivor.

At least seven of these outbreaks were triggered by the virus lingering silently in people who have recovered from Ebola. By tracing its evolution, researchers have now discovered how the virus does this: it completely shuts down and doesn’t even replicate – something never seen before in this type of virus.

In January, the WHO declared that there had been no cases of Ebola in Liberia, Guinea and Sierra Leone for 42 days – twice the maximum time it takes an infected person to show symptoms. That should normally mean that a virus is gone.

But the West African epidemic has shown that the Ebola virus can hide in organs that are sheltered from the immune system, such as the eye and testes, and then re-emerge – as happened in case of Pauline Cafferkey, a British nurse who fell ill again nine months after recovering from Ebola.

Jason Ladner at the US Army Medical Research Institute of Infectious Diseases in Fort Detrick, Maryland, and his team examined a flare-up of Ebola in Liberia in June 2015. At that time, Liberia had experienced no Ebola cases for three months, but then a 17-year-old in the town of Needowein died and tested positive for the virus.

Seven of his contacts also tested positive, and one of them died. When the team sequenced their viral strains, they found that they were genetically similar to others that had been seen in the Liberian epidemic, meaning Ebola had not been newly contracted from host animals or another country.

The sequences also revealed a virus caught in a time warp. RNA viruses like Ebola make mistakes as they replicate their genes. But the virus from the Needowein outbreak showed no new mistakes compared with samples taken 10 months earlier.

To slow its mutation rate to a standstill, the virus must effectively have stopped replicating, the team say. This has been seen before in a more complex DNA virus, but never in an RNA virus.

The researchers think the Needowein outbreak probably began with a woman who had cared for people with Ebola in a neighbouring village – 10 months earlier. She developed unusual symptoms but didn’t suspect Ebola, and later moved to Needowein.

The team have identified similar patterns in other Ebola outbreaks. In March 2015, a survivor infected his wife via semen, and the virus looked like those that were circulating months earlier when her husband was ill.

Analysing 294 more sequences, the team found 15 that were similarly out of sync with their times.

According to the WHO, Ebola can lurk undetected for 15 months – half a year longer than previously thought. This means unknown numbers of the 17,000 people who survived the West African epidemic could pose an infection risk for some time.

In March this year, 10 people in Guinea got Ebola after a man who had recovered from it 15 months earlier infected his wife via semen.

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[laklak]

The take away from this is don't get Ebola.

[piscator]

Tick Tick Tick...

[pErvinalia]

Tricksy virus..

[JimC]

A good design feature for the product of a biowar lab...



I'm turning into Galaxian...

[cronus]

A good design feature for the product of a biowar lab...



I'm turning into Galaxian...

If ET were to attack with certainty of result he'd use Ebola and Zika as the pincers for human extinction. We'll know within five years.