Ebola - is this normal?

#1
I read somewhere that besides the current bigger outbreak in Liberia, there is also a smaller outbreak of ebola in Kongo. The thing is that these strains are not connected.
How is that possible? Especially with a dangerous virus like ebola we have a pretty good system to recognize it when it pops up somewhere, and as I understand it has been dormant for some years, until now. Is it just coincidences, or is there a cycle to it somehow?
 
#2
There are many theories of where does the virus "hide" in between the endemic outbreaks (that is, where does the virus go when no one or few people are sick and from where does it come when another little outbreak begins?). One theory for example holds that some bats are immune to the symptoms of ebola but can still work as asyntomatic hosts, and hence can be their reservoir in between the outbreaks, since no one would notice any syndrome in bats, but they can potentially infect a human, thus beginning a new outbreak, apparently out of nowhere. here more: http://news.nationalgeographic.com/news/2003/02/0219_030219_ebolaorigin.html As you rightly pointed out, figuring out the "cycle" can be quite helpfull in developing strategies to attack it based on epidemiology.

Hope that helps.
 
#3
There are many theories of where does the virus "hide" in between the endemic outbreaks (that is, where does the virus go when no one or few people are sick and from where does it come when another little outbreak begins?). One theory for example holds that some bats are immune to the symptoms of ebola but can still work as asyntomatic hosts, and hence can be their reservoir in between the outbreaks, since no one would notice any syndrome in bats, but they can potentially infect a human, thus beginning a new outbreak, apparently out of nowhere. here more: http://news.nationalgeographic.com/news/2003/02/0219_030219_ebolaorigin.html As you rightly pointed out, figuring out the "cycle" can be quite helpfull in developing strategies to attack it based on epidemiology.

Hope that helps.
Ahh, so you mean the strain lays dormant with lots of bats, and on any given they it starts to evolve and the bats spread it over a larger area.

But we still have the problem of them being of a totally different strains, and shows up almost instantaneously miles from each other.

PS: I also read that Ebola could rather quick evolve itself to be airborne - and then all the "fun" starts. Head for the hills!!!
 
#4
Ahh, so you mean the strain lays dormant with lots of bats, and on any given they it starts to evolve and the bats spread it over a larger area.

But we still have the problem of them being of a totally different strains, and shows up almost instantaneously miles from each other.

PS: I also read that Ebola could rather quick evolve itself to be airborne - and then all the "fun" starts. Head for the hills!!!
I don't see the particular problem though, at least as far as my understanding of microbiology goes. The strains might have a distant common antecessor from many years ago (like, a family of bats got infected and then both families got away from each other further and further, and in the time, developing different strains of Ebola), while both the one and Kongo and the one at Liberia infecting their own population of bats. Then, by sheer coincidence, both might have passed unto humans and hence beginning two disconnected Ebola breaks. The coincidence part is interesting, but as they say, "sh*t happens".

As for your PS, I've also heard that, and I think it's a potential thread in any biological entity that has the power to mutate a lot in short periods, specially when humanity is putting selective pressure on them, I think at the end it depends a lot on the mutation rate of the virus, which I think it's largely unknown. Becoming airborne would definitively make it more deadly and dangerous. We can only hope it doesn't.
 
#5
Then, by sheer coincidence, both might have passed unto humans and hence beginning two disconnected Ebola breaks. The coincidence part is interesting, but as they say, "sh*t happens"..
Yeah, it was the "shit happens" part of it i found strange. Long before glottalization, open borders, and 24/7 flight to every corner of the earth was possible, there was these "pockets" of rare and aggressive viruses sprung up almost simultaneous on remote places around the world. It might be birds, but if so we would see tons of other diseases. Diseases birds brings with them when they migrate -.but we dont
 
#6
Yeah, it was the "shit happens" part of it i found strange. Long before glottalization, open borders, and 24/7 flight to every corner of the earth was possible, there was these "pockets" of rare and aggressive viruses sprung up almost simultaneous on remote places around the world. It might be birds, but if so we would see tons of other diseases. Diseases birds brings with them when they migrate -.but we dont
¿Do you have any article on this pre-modern era situations? That looks interesting. As for how we should take this cases ( as mere coincidences or something else), I'm not sure, ¿what do you suggest? I sometimes think that some might be coincidences, but others might involve a more direct human approach (like, engineering the situation), but for pre-modern cases I have no clue, since nobody would have had the technology, knowledge and the resources to achieve such a task and micro-biological entities don't seem to have the intelligence and organization to do it neither.
 
#7
Yeah, I can look and see if I find them. The second one was in a science journal. The newer one about Kongo was in the paper the other day, so it shouldn't be to hard to find. It would be nice to see if it actually was man-made - the transport of the virus - or by birds. Otherwise one can speculate on some sort of a 100-monkey-scenario and intelligent viruses. Like this one>>
 
C

Chris

#9
PS: I also read that Ebola could rather quick evolve itself to be airborne - and then all the "fun" starts. Head for the hills!!!
Funnily enough, I just read that no virus has ever been known to change its method of transmission.
 
#12
Growing concerns over 'in the air' transmission of Ebola

Canadian scientists have shown that the deadliest form of the ebola virus could be transmitted by air between species.

In experiments, they demonstrated that the virus was transmitted from pigs to monkeys without any direct contact between them.

The researchers say they believe that limited airborne transmission might be contributing to the spread of the disease in some parts of Africa.

They are concerned that pigs might be a natural host for the lethal infection.
Ebola viruses cause fatal haemorrhagic fevers in humans and many other species of non human primates.

Details of the research were published in the journal Scientific Reports.

According to the World Health Organization (WHO), the infection gets into humans through close contact with the blood, secretions, organs and other bodily fluids from a number of species including chimpanzees, gorillas and forest antelope.

The fruit bat has long been considered the natural reservoir of the infection. But a growing body of experimental evidence suggests that pigs, both wild and domestic, could be a hidden source of Ebola Zaire - the most deadly form of the virus.

Now, researchers from the Canadian Food Inspection Agency and the country's Public Health Agency have shown that pigs infected with this form of Ebola can pass the disease on to macaques without any direct contact between the species.

In their experiments, the pigs carrying the virus were housed in pens with the monkeys in close proximity but separated by a wire barrier. After eight days, some of the macaques were showing clinical signs typical of ebola and were euthanised.

One possibility is that the monkeys became infected by inhaling large aerosol droplets produced from the respiratory tracts of the pigs.
One of the scientists involved is Dr Gary Kobinger from the National Microbiology Laboratory at the Public Health Agency of Canada. He told BBC News this was the most likely route of the infection.

"What we suspect is happening is large droplets - they can stay in the air, but not long, they don't go far," he explained.

"But they can be absorbed in the airway and this is how the infection starts, and this is what we think, because we saw a lot of evidence in the lungs of the non-human primates that the virus got in that way."

The scientists say that their findings could explain why some pig farmers in the Philippines had antibodies in their system for the presence of a different version of the infection called Ebola Reston. The farmers had not been involved in slaughtering the pigs and had no known contact with contaminated tissues.

Dr Kobinger stresses that the transmission in the air is not similar to influenza or other infections. He points to the experience of most human outbreaks in Africa.

"The reality is that they are contained and they remain local, if it was really an airborne virus like influenza is it would spread all over the place, and that's not happening."

Hidden host
The authors believe that more work needs to be done to clarify the role of wild and domestic pigs in spreading the virus. There have been anecdotal accounts of pigs dying at the start of human outbreaks. Dr Kobinger believes that if pigs do play a part, it could help contain the virus.

"If they do play a role in human outbreaks it would be a very easy point to intervene" he said. "It would be easier to vaccinate pigs against Ebola than humans."
Other experts in the field were concerned about the idea that Ebola was susceptible to being transmitted by air even if the distance the virus could travel was limited. Dr Larry Zeitlin is the president of Mapp Biopharmaceuticals.

"It's an impressive study that not only raises questions about the reservoir of Ebola in the wild, but more importantly elevates concerns about ebola as a public health threat," he told BBC News. "The thought of airborne transmission is pretty frightening."

At present, an outbreak of ebola in Uganda has killed at least two people near the capital Kampala. Last month, Uganda declared itself Ebola-free after an earlier outbreak of the disease killed at least sixteen people in the west of the country.
http://www.bbc.com/news/science-environment-20341423
http://www.nature.com/srep/2012/121115/srep00811/full/srep00811.html
 
#14
Yeah, I can look and see if I find them. The second one was in a science journal. The newer one about Kongo was in the paper the other day, so it shouldn't be to hard to find. It would be nice to see if it actually was man-made - the transport of the virus - or by birds. Otherwise one can speculate on some sort of a 100-monkey-scenario and intelligent viruses. Like this one>>
The video is interesting. At first I though about replying that cells have a biochemical function that can describe their behaviour toward bacteria and hence aren't intelligent because they don't think. But then I though that my definition of intelligence does allow machines like computers to be intelligent, so why not cells?

It would be helpfull if you coul catch those papers, to learn more.
 
C

Chris

#15
I think it depends what you mean by "airborne". That paper says:
The experimental setting of the present study could not quantify the relative contribution of aerosol, small and large droplets in the air, and droplets landing inside the NHP cages (fomites) to EBOV transmission between pigs and macaques. These parameters will need to be investigated using an experimental approach specifically designed to address this question.

And in the BBC report you linked to, one of the authors is quoted as saying that they are not talking about airborne transmission in the sense that flu transmission is airborne:
Dr Kobinger stresses that the transmission in the air is not similar to influenza or other infections. He points to the experience of most human outbreaks in Africa.
"The reality is that they are contained and they remain local, if it was really an airborne virus like influenza is it would spread all over the place, and that's not happening."


I can't see any indication there that the virus is likely to evolve so that it does become transmissible in a similar way to flu.
 
#18
The video is interesting. At first I though about replying that cells have a biochemical function that can describe their behaviour toward bacteria and hence aren't intelligent because they don't think. But then I though that my definition of intelligence does allow machines like computers to be intelligent, so why not cells?

It would be helpfull if you coul catch those papers, to learn more.
What I found interesting in that clip was that the white blood cell had it in for that particular bacteria. As you can see it chases it along when it comes up to another bacteria that didn't "flee" like the first one. Which would have made it an easier target. The "point & purpose" of a pure reactionary blood cell should be, I think, to annihilate every possible threat, and if it's an "easier target" it should go for that immediately.

I know its pretty hard to think of this as a `calculating´and fully conscious blood cell that makes calculating decisions, but it sure looks like some sort of calculating reflexes there. Maybe some expert in blood cells here can enlighten us.
 
#19
I think it depends what you mean by "airborne". That paper says:
The experimental setting of the present study could not quantify the relative contribution of aerosol, small and large droplets in the air, and droplets landing inside the NHP cages (fomites) to EBOV transmission between pigs and macaques. These parameters will need to be investigated using an experimental approach specifically designed to address this question.

And in the BBC report you linked to, one of the authors is quoted as saying that they are not talking about airborne transmission in the sense that flu transmission is airborne:
Dr Kobinger stresses that the transmission in the air is not similar to influenza or other infections. He points to the experience of most human outbreaks in Africa.
"The reality is that they are contained and they remain local, if it was really an airborne virus like influenza is it would spread all over the place, and that's not happening."


I can't see any indication there that the virus is likely to evolve so that it does become transmissible in a similar way to flu.
Yeah, evolve was maybe the wrong word. I meant it in the sense they presented it; that it could be transmitted by a sneeze or perspiration, where droplets, even in `mist-form´, can travel quite some distance on its own, and still remain contagious for quite a while. This is a sort of airborne, but not at such a large scale as some sort of flu though. It seem less likely that ebola could transform itself to act like that.
 
#20
Yeah, I can look and see if I find them. The second one was in a science journal. The newer one about Kongo was in the paper the other day, so it shouldn't be to hard to find. It would be nice to see if it actually was man-made - the transport of the virus - or by birds. Otherwise one can speculate on some sort of a 100-monkey-scenario and intelligent viruses. Like this one>>
Beautiful. Truly. And even though I've seen such videos a million times before, it never gets any less incredible.
 
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