Tag Archives: Ebola

Ebola — an update (25 Oct ’14)

The experiment of nature referred to in a previous post (https://luysii.wordpress.com/2014/10/16/an-experiment-of-nature/) when Amber Vinson, a nurse who had helped care for a fatal case of Ebola, took a commercial flight from Cleveland to Dallas the day she became symptomatic with Ebola is almost over. She was diagnosed 14 October, the day she took the flight, and so far no one on the flight has become ill (presumably the 100+ or so are under surveillance).

However, another experiment of Nature has just begun. An M. D. who’d been in Africa treating Ebola victims was diagnosed with it on the 23rd. He had returned to NYC from Africa 14 October and had been up and about in the city. According to the Times he began to feel sluggish the evening of the 21st, went all over the city on the 22nd, including a 3 mile jog on the west side, and noted a mild temperature (100.3 not 103 as initially reported) the morning of the 23rd — reported it immediately and was hospitalized the same day. New York City chastened by the disastrous response to the first case in Texas, sent 3 guys in Hazmat suits to his apartment to pick the doctor up, according to the NYT of 26 October. Some contacts, such as his fiancee are easy to trace, the people he rode with on the subway are not.

The incubation period is said to be no more than 21 days, so neither experiment of nature is truly over. From this case we now know the incubation period can be as short as 7 – 9 days.

As noted in the previous post — The genome of Ebola is RNA which mutates much more rapidly than DNA genomes. It does this so quickly that at death from AIDS (another RNA virus), there are so many viral variants present that the infecting ensemble is called a quasiSpecies. With a large population infected in Africa there is more Ebola virus extant than at any time in the past.

We have a small handle on just how fast the virus is mutating [ Science vol. 345 pp. 1369 – 1372 ’14 (12 Sep ’14) ]. This is a report of 98 virus genomes from 78 patients from Sierra Leone (all this year). The Ebola genome contains 18,959 to 18,961 nucleotides and codes for at least 7 proteins. Compared to all previously known Ebola genome sequences, the virus from Sierra Leone contains 341 fixed changes (e.g. the changes were present in every virus they sequenced). The changes were present in all 7 proteins.

It isn’t clear (to me) from reading the paper how much variation in the viral genome there is (1) in a given individual (2) between individuals. Note that all samples were obtained from late May to early June this year, so the work is a good baseline.

Why is this scary? Because, as is typical for a virus with a genome made of RNA, Ebola is mutating rapidly. This means that we can’t be sure that its incubation characteristics, or its ability to spread from human to human will remain constant.

Producing the paper, required lots of collaboration between people in the USA and Africa, so there are 58 co-authors of the paper. Showing just how bad the disease is five of the fifty-eight co-authors died of Ebola. R. I. P. Mohamed Fullah, Mbalu Fonnie, Alex Moigboi, Alice Kovoma, S. Humarr Khan.

An experiment of nature

Yesterday’s post https://luysii.wordpress.com/2014/10/15/ebola/ concerned the fact that 2 nurses taking care of a patient in Texas had been infected (presumably even after taking all the recommended precautions). Given that, I was concerned about the possibility of airborne spread.

Bryan wrote in to say the following:

“It seems doubtful airborne spread was involved. Remember, the Texas patient was initially sent home after showing symptoms, yet none of his family members were infected. Only those health workers directly involved in his care (and thus exposed to infected bodily fluids) have been infected, consistent with the idea that the disease can be transmitted only though contact with infected bodily fluids.”

I certainly hope he is right.

In something right out a novel, the possibility of airborne spread is now going to be empirically tested, as one of the two infected nurses flew to Cleveland, and then back to Texas in the 24 hours prior to her diagnosis. She apparently had a slight fever on boarding. So 100+ people were in a confined space with her for a few hours.

It’s why I don’t read fiction — reality is far more fantastic than anything writers can produce.

One more bizarre development. Here in Massachusetts, legislators today are scheduled to hear about the readiness of the state’s hospitals to handle Ebola. Amazingly, they will only get input from hospital CEOs. No nurses, thank you. Naturally the nurses are pissed as they should be (and so should you if you live in the state). If there were ever a time to hear from boots on the ground about Ebola readiness, it is now.

Addendum 17 Oct ’14

The Obama administration has just appointed a former chief of staff for former vice-president Gore and present vice-president Biden as the “Ebola czar”. Presumably, not for his medical expertise but for his ability to coordinate various governmental agencies, which was hardly the problem in the CDC’s response to the Texas cases. Hopefully, this will not be another case of “Brownie, you’re doing a heck of a job,” but I’m not optimistic — http://en.wikipedia.org/wiki/Michael_D._Brown

Now for some molecular biology. The genome of Ebola is RNA which mutates much more rapidly than DNA genomes. It does this so quickly that at death from AIDS (another RNA virus), there are so many viral variants present that the infecting ensemble is called a quasiSpecies. With a large population infected in Africa there is more Ebola virus extant than at any time in the past. There is some reason to hope that natural selection for a more transmissible form of Ebola in the large infected human population will not occur (the AIDS virus hasn’t become more infectious over the years). This is only a hope.

Ebola

This morning (15 October) it was announced that a second health care worker at the Texas hospital where an ebola patient died has ‘tested positive’ for it. If ebola can spread in a hospital environment where presumably precautions were taken, once it gets out into the populace at large it can spread much faster. This had to be human to human transmission — no other animal vector is involved (as it probably is in Africa).

How does it spread? We don’t know, but the two Texas cases probably imply that airborne spread is possible.

What to do?

In our case it means not getting into a confined space with over 100 people we don’t know from all over the world for an 8 – 16 hour period (e.g. an international flight). Have you ever been on a flight where no one had a cold?

For the USA, it should mean banning all flights from endemic countries. This has been the case in the past. My cousin’s wife has a lot of relatives in Brazil, because the people on the boat had lots of pink eye, and the boat was simply turned away over 100 years ago.

It should mean caring for Ebola patients in specialized facilities where only they are cared for –e.g. not in a general hospital since we don’t know how it spreads.

The greatest way to spread the disease (the Hajj — millions of people from all over the world crowded together for days followed by worldwide dispersal) has mercifully just ended before the disease escaped Africa to any extent.

Will ISIS or Al-Qaeda try to bring Ebola to the USA? Of course.

We live in a society where children have supervised play dates, and where walking unattended to school is almost considered child abuse. What will happen to such a risk-averse society when there is actual risk to going out to (the mall, the school, to work)?