I don’t have enough information to comment, but I since the outbreak left its cage in recent days, I’ve suspected that they are being disingenuous about the vectors - both the number and the character of the vectors.
One report said one could become infected by as little as 1 to 10 virus in any given human. Compare that to, say sperm and impregnation. You send millions down the pipe and many times nothing happens.
If only a sample of 1 to 10 individual virii is all it takes to catch the bug, and I say IF, because we don’t know that’s true at this point; you can easily see how that many virii can live on the end of the mouth of a mosquito. To know for sure, you’d have to catch a mosquito that had been dining on a patient and test your theory.
But there are all kinds of issues with secondary vectors. Locally, a mosquito can help you wipe out a great deal of people very quickly - even the ones who are being good and isolating themselves and their families within their homes. A mosquito gets in, bites you in your sleep and you wake up 3 weeks later symptomatic and think it was an evil form of magic.
We haven’t seen any anecdotes that would indicate that’s happening. When you read stories where old shut-ins are dying alone in their homes of the bug, then you start worrying about that. When malaria was off the chain, you had that sort of thing happen - shut ins getting the bug and you wonder how the heck it was happening. Well, during the summer, it comes in through the window.
With plague, it was the fleas. Fleas are perfect as a vector, because they are hardy, efficient at reproduction, and they travel well.
Again, if it only takes 1 to 10 virii, then a flea would be a nightmare intermediate vector.
From what I’m reading, I don’t think that’s what’s happening.
However, now you hear reports of bodies dumped out on the streets. Sorry, but if that’s happening then numbers like 729 dead are likely out the window, and because the bodies are being fed upon efficiently by all the usual suspects that do nature’s clean up job on things that die, you might just find that an intermediate vector will pop up and drop the accelerator on this bug.
Based on what I’ve read, what fits best is the following:
1. Aerosol is a vector.
2. Patients become contagious somewhere in the timeline between infection and first presentation of symptoms.
Based on the incubation period, I tend to believe the reports that it only takes 1 to 10 virii. The answer is math.
The virus has to attach to a viable human cell, inject its RNA into the nucleus, and convert that cell into a manufacturer of more virii. The new virii infect other cells, and they become manufacturers, and on, and on.
You start with just one cell, it takes time to build the numbers required to start bringing the immune system down to the point where you start presenting.
With Zaire, the incubation process was so rapid you started presenting almost right away.
Not so with this one. It builds up, and there is likely a some point prior to the presentation of symptoms that you become contagious. That explains, for me, the five people who died in the communal cab. If the infected person has so much as a runny nose or a dust-induced cough, there is no way they would have let her ride. None.
Africans have cell phones. Word spreads faster now that it did in the 60’s when some of these contagions would hit countries down there. Everybody is going to be looking for symptomatic people and turning them out.
If I had to GUESS why it left the chain, I’d say it was because the Generals started fighting the last war - it looked like Ebola, tested out Ebola, and since Ebola is spread through blood and fluids, we will rig for Ebola.
Problem is that while it IS Ebola, it’s a little different this time, and different enough that they were too slow on the containment end. Add to that carelessness and fatigue, and you end up with a whole bunch of infected health care workers. In other Ebola outbreaks, they didn’t have the infection rate among docs and nurses that this one appears to have.
British Airways closed down ‘infected’ countries today. That list will grow before Friday gets here, because now it is apparently in Nigeria, and maybe Gabon.
I would expect South Africa to seal its borders in the next couple of weeks or so. They are far enough away that sealing now may keep it out of there. They’ll screen and actively test freight traffic into it, but civilian travel into SA from infected countries could well close soon.
Sorry about the non-answer answer, but there isn’t enough information for even an analysis of what probably happened. All we have is anecdotal information about patterns of infection.
There has been ZERO about intermediate vectors in the press - not even speculation.
Thank you so much for a very informed reply.
I agree re: aerosol transmission. If it requires only 1 virii to infect then someone coughing can easily infect a whole room.
Sealed hospital rooms would be detrimental in this case vs. camp tents in the bush. And would explain why this particular outbreak in urban/suburban areas ramped up so quickly.
If it’s spread before people become noticeably symptomatic that would explain why the villagers think the healthcare workers bring it with them. Given so many healthcare workers have become ill, they MAY be bringing it with them.
I will pray that mosquitos aren’t a vector. if they are, Africa will depopulate drastically.
To comment on your earlier post, it would appear from the graph that R0 is much greater than one at this point? But who really knows how many dead bodies there are. It’s Africa. And people are in a panic.
Would you think the difference between the mortality of this outbreak vs the past ones may be that so many people have become infected so quickly that they simply haven’t had time to die and become mortality datapoints just yet?
Cuh-rap! What about all the folks who have to fly, for their jobs? Yikes!