Thursday, October 15, 2015
Human Ebola Virus
Yo, Whas Up?
When scientists want to study Ebolavirus, they usually take a sample and run it through a few generations of a host to get good replication. That is, you grab an unfortunate guinea pig, inoculate the poor thing, pull a sample of the virus out after it is really ill, inoculate another, and so on. Within four to ten cycles, you have a virus that is really good at incubating in guinea pigs. You keep this quiet, because the last thing you need is a bunch of PETA people trying to rescue your Ebola-infected guinea pigs. This is not a joke.
This is what we just did in the Zaire outbreak, only with humans, unintentionally, implying that those infected, say after July or August of 2014 have some strains of a quite mutated virus that is now more specialized for humans, and very probably some strains that are mutated to be a little less virulent, thus leaving more carriers.
Second Verse, Same As The First!
They already knew that it took months for the virus to clear from prior outbreaks. They released these people back into the community, only giving some instructions about avoiding nursing and employing safe sex precautions for a few months. Inevitably, some of these instructions weren't followed, and some sexual transmission occurred. I know Sierra Leone arrested at least two men for not following the safe sex instructions.
Only one case has been fully documented - the six-month transmission in Liberia. Note that the unfortunate carrier did not violate the instructions he was given, so he bears absolutely no moral culpability. Again, this was a public health SNAFU. It still has not been fully corrected.
But there's a whole lot that the public wasn't told. First, that survivor had had sex with another woman several times shortly BEFORE he infected the lady who died, and at least once after. They did get a partial sequence out of later testing on his semen, which appeared to match her strain. This is as close as you can get to the gold standard.
HOWEVER, it probably means that the man wasn't infectious when he slept with the first lady, but was when he slept with the deceased. I.E. clinical recurrence, or a waxing and waning of viral levels. This is somewhat supported by the fact that of two semen samples taken about a week apart after the death of the contact, the first was negative by RT-PCR and the second was weakly positive. Thus, WHO's current instructions to survivors probably aren't adequate either - they now call for indefinite safe sex until two tests one week pr one month apart of the semen test negative. This seems doubtful coverage.
As a consequence of the July confirmation of six month sexual transmission, a follow-up study has been initiated, showing that, indeed, viral traces are found in the sperm of at least some survivors for at least nine months. Indeed, for as long as they have been checking:
The preoccupation is still heavily about avoiding stigma, but failure to give adequate early precautions must now have ensured that the public doesn't trust the experts, so more of the same is perhaps not advisable. In fact, it is only the "prejudice" of the local populations affected that have probably prevented quite a bit of potential numbers of infections, and indeed it is only late in the cycle when most of the transmission chains have been broken that such types of transmissions can be picked up in an area in which the disease has been endemic.The men joined the study between two and 10 months after they were infected with Ebola.All those who were tested in the first three months after their illness showed positive results for Ebola in the semen.Four to six months after diagnosis, 65 percent were positive.About a quarter (26 percent) of those tested between seven and nine months were positive.
So Let's Take A Stab At The Numbers:
There are over 16,000 living Ebola survivors (estimated). Not all of them are known, either. If even 10% of them were producing live virus six months out (probably far, far more), then there were 1,600 persons potentially capable of passing it through bodily fluids.
This would lead to a very low, slow run of transmission, but a VERY selective filter indeed. Now you have the virus competing not for virulence, but for persistence. This was what you needed to avoid in the first place. In effect, we have a bred a human strain of Ebola virus, and it isn't the same as the original one any more. Expect the unexpected. It is the only reasonable thing to do.
But it is far more probable that the six month number was 3,000-7,000.
Now, although transmission is just a signal, the mutation war is on for persistence, and that war is being fought in thousands of individual bodies. It is probable that the first sets of mutations occurred during the endemic stage, and now we have thousands of incubators, each evolving their own strains, each strain fighting to survive in the human body over the long term.
They aren't even looking in the right place to find it, either. They should be testing women of child-bearing age, because those women have a natural hormonally adjusted down-regulation of the immune system for about half their monthly cycle, and by testing the flux of antibodies they could tell if the virus is hanging out and resurging. And it is way more likely to resurge if we have long-term carriers and if they get pregnant. Way more likely.
Which Brings Us To The Unexpected Expected British Nurse:
Poor lady. She is in critical condition. Nothing about this is her fault - we can only hope she survives and recovers well. She probably has meningitis or encephalitis. The most likely reservoirs are joints and CNS, and if she had virus in the CNS and got on the plane for an awards ceremony a week before she got ill, the pressure changes may have forced some virus out into her system when her circulating immunities had dropped enough to let it run a bit.
But is this really so rare? I doubt it. Given the little known, and the very great difficulties and dangers of trying to study the virus in situ, it seems likely that she isn't that rare. There have been significantly less than 100 survivors in the west. It's extremely unlikely that she is that one-in-a-thousand chance. She's way more like to be the one-in-thirty chance.
The British are contact tracing, and they have used the experimental vaccine on more than twenty contacts. Obviously they aren't sure that she wasn't contagious to family and the initial medical contacts.
Maybe it's time to throw some real money at this problem! Open up clinics in West Africa, try to really treat the survivors, and do follow-up testing for years on the survivors. If you just test for immunities circulating, you will be able to tell if the virus is still hiding and replicating in their bodies.
If you don't do this, and even if you mass-produce the vaccine, which is obviously the right thing to do, you may miss cases and end up transmitting a really human-adapted virus. Probably through a medical setting! A joint injury, an eye injury, or just pregnancy can reintroduce the human-adapted Ebola strain into a medical setting unpredictably.
Are we willing to take the chance that this will end up in India, China or South America? This one we need to study.
Yeah, the last thing you'd want is an outbreak in one of those countries where the government systematically suppresses bad news in order to make themselves look good.
Global economic crash coming - check.
Muslim expansion/ invasion proceeding worldwide - check.
A government "of, by, and for" the members of said government (and their clients, cronies, collaborators, and lackeys) - check.
No control of the borders, draw-down of military forces, "de-norming" of rule-of-law, make LEO's fearful to do their jobs, etc-etc-etc - check.
And now, on top of the "rare and unusual" diseases being brought over our unguarded southern border, we get to worry about human-reservoir Ebola, too.
The End Times seem to be coming along nicely, eh?
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On a different medical note:
M-O-M, do you have any additional word on your work with Super Doc? It's been ages since we had an update, and it's such a fascinating topic...
(Have to post anonymously [hah!] now, since Google Account seems not to like me any more!!)