Mystery of Ebola cases sharp drop.

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Scientists ask if Ebola immunizes as well as kills
By Kate Kelland and Emma FargeLONDON/DAKAR (Reuters) -

 A recent unexpected sharp drop in new Ebola infections in West Africa is prompting scientists to wonder whether the virus may be silently immunizing some people at the same time as brutally killing their neighbors.

So-called "asymptomatic" Ebola cases - in which someone is exposed to the virus, develops antibodies, but doesn't get sick or suffer symptoms - are hotly disputed among scientists.

"We wonder whether 'herd immunity' is secretly coming up - when you get a critical mass of people who are protected, because if they are asymptomatic  they are then  immune," Philippe Maughan, senior operations administrator for the humanitarian branch of the European Commission, told Reuters. "The virus may be bumping into people it can't infect any more."

Latest World Health Organization data show new cases of infection in West Africa's unprecedented Ebola epidemic dropping dramatically in Guinea, Sierra Leone and particularly in Liberia.

Most experts still feel the main driver is better control measures reducing direct contact with contagious patients and corpses, however the decline is so rapid, there may also be other more natural factors at work.

So-called herd immunity is a feature of many infectious diseases and can, in some cases, dampen an outbreak if enough people get asymptomatic, or "sub-clinical" cases and acquire protective antibodies. After a while, the virus - be it flu, measles, polio - can't find enough non-immune people to be its hosts

With the largest Ebola epidemic on record raging through three of Africa's most under-resourced countries, scientists and medics have, understandably, focused all efforts on the sick and dying and not on testing people with no symptoms.

If they do, however, and if they were to find what some others suspect, it could prompt a reappraisal of what jolted a relatively sudden downturn in new cases.

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Hazelpad Members Profile Send Private Message Find Members Posts Add to Buddy List Adviser Group Joined: September 09 2014 Status: Offline Points: 6910	Post Options Post Reply Quote Hazelpad Report Post Thanks(0) Quote Reply Topic: Mystery of Ebola cases sharp drop. Posted: January 28 2015 at 4:21am
	Scientists ask if Ebola immunizes as well as kills By Kate Kelland and Emma FargeLONDON/DAKAR (Reuters) - A recent unexpected sharp drop in new Ebola infections in West Africa is prompting scientists to wonder whether the virus may be silently immunizing some people at the same time as brutally killing their neighbors. So-called "asymptomatic" Ebola cases - in which someone is exposed to the virus, develops antibodies, but doesn't get sick or suffer symptoms - are hotly disputed among scientists. "We wonder whether 'herd immunity' is secretly coming up - when you get a critical mass of people who are protected, because if they are asymptomatic they are then immune," Philippe Maughan, senior operations administrator for the humanitarian branch of the European Commission, told Reuters. "The virus may be bumping into people it can't infect any more." Latest World Health Organization data show new cases of infection in West Africa's unprecedented Ebola epidemic dropping dramatically in Guinea, Sierra Leone and particularly in Liberia. Most experts still feel the main driver is better control measures reducing direct contact with contagious patients and corpses, however the decline is so rapid, there may also be other more natural factors at work. So-called herd immunity is a feature of many infectious diseases and can, in some cases, dampen an outbreak if enough people get asymptomatic, or "sub-clinical" cases and acquire protective antibodies. After a while, the virus - be it flu, measles, polio - can't find enough non-immune people to be its hosts With the largest Ebola epidemic on record raging through three of Africa's most under-resourced countries, scientists and medics have, understandably, focused all efforts on the sick and dying and not on testing people with no symptoms. If they do, however, and if they were to find what some others suspect, it could prompt a reappraisal of what jolted a relatively sudden downturn in new cases.

Technophobe Members Profile Send Private Message Find Members Posts Add to Buddy List Assistant Admin Joined: January 16 2014 Location: Scotland Status: Offline Points: 88450	Post Options Post Reply Quote Technophobe Report Post Thanks(0) Quote Reply Posted: January 28 2015 at 5:17am
	Sea-mist, our resident researcher/moderator over on the Ebolainfo site thinks the same. I agree with you both. This is a very logical conclusion: Obviously unproven, but it fits all the facts.
	How do you tell if a politician is lying? His lips or pen are moving.

onefluover Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: April 21 2013 Location: Death Valleyish Status: Offline Points: 20151	Post Options Post Reply Quote onefluover Report Post Thanks(0) Quote Reply Posted: January 28 2015 at 5:27am
	Meaning, if this were the case, the threat was far worse than the most dire predictions of the speed of its spread. Meaning many millions would have to have by now been exposed. Now what if that were the case but the CFR remained in the 80's? The attention given -and fears of Ebola, were not overblown in any case.
	"And then there were none."

Hazelpad Members Profile Send Private Message Find Members Posts Add to Buddy List Adviser Group Joined: September 09 2014 Status: Offline Points: 6910	Post Options Post Reply Quote Hazelpad Report Post Thanks(0) Quote Reply Posted: January 28 2015 at 8:16am
	Correct One flu. There is much to learn. If asymptomatic immunisation has occurred they need to first establish how widespread this is ( are we seeing true herd immunity in West Africa, or is it more focal I.e. immunity in certain areas, local, household etc. It will also give a more accurate CFR. If asymptomatic cases with antibodies are found ( as seen in previous smaller outbreaks ). It may not just be a simple case of genetic differences between individuals protecting some and not others. The route of transmission, or the viral load initially exposed to are often important factors, etc etc. The route of exposure is an interesting variable. Different components of the immune system are active in different mucosal areas, each has antimicrobial strategies developed to cope with the type of reaction needed at that location, hence although the mucosal immune system shares features, the gut has evolved to cope with common food and water bourne pathogens, while in contrast the airways evolved to fight common airbourne agents. Every entry point of the body is protected by different combinations. Even if a virus does not have tropism for certain locations, the immune system can often reach it through specialised cells and what they call " sample it". The whole field of oral immunisation is huge, and the potential for vaccines to be delivered to the vaginal or rectal mucosal membrane,( termed vaccine without needles) is growing. On top of this the systemic immune system and mucosal system are even more distinct from one another. Bacteria we happily eat, would be lethal if released into the blood etc etc. Therefore it is feasable that one route of exposure to ebola could in theory give a more favourable outcome than the other. What about environment exposure. Ebola is very susceptibility to UVA. If you pick virus up from surface out in direct sunlight where the UV light has damaged it, is that virus in affect an attenuated vaccine ( cant cause disease but still can cause an immune reaction), rather than an active biohazard. Good epidemiological studies need to be done, and hopefully some should have been done in real time ( during the outbreak, stored samples etc). This type of information will be of real use.