Google
 

Friday, December 02, 2005

Ebola Host Identified

Scientists believe they have found the carrier of Ebola virus - fruit bats tested during outbreaks in Gabon and the Republic of Congo were found to be carrying it (without symptoms.)
The excellent factual book Hot Zone by Richard Preston is split into two parts: the first part describes Ebola and various outbreaks in Africa. The second part covers an outbreak in a monkey house in Washington by a virus showing properties identical in many ways to Ebola. (It killed the monkeys - but did not jump species .. much!)
In Hot Zone, a cave is found - Kitum cave - in Africa which links two separate single-incidence occurrences of Ebola. Scientists eventually go to the cave and take blood samples from absolutely everything they can find. (Except elephants - "Did you ever try to take a blood sample from an elephant?" - and big cats.) They found nothing at all and the results were never formally published. Kitum cave was absolutely stuffed with bats, so the fruit bat find could explain how two people died of Ebola in separate incidents after visiting Kitama cave.
A successful virus does not kill its host. It has a symbiotic relationship, the lack of serious harm to the host allows it to survive. When the traditional host of a virus is wiped out, the virus will try to jump species, and it will mutate. A virus that is benign to a moth may be a killer of humans. Viruses like meat ... and the largest source of meat on the planet is human. Conserving the environment can keep these killers in harmless hosts inside the rain forests and jungles of the world. Wipe out their environments and the hosts will die, the viruses will mutate and jump species, and we could be in serious trouble.
Richard Preston (Hot Zone author) has an excellent website.
Very useful information from the CDC relating to Ebola and many other viruses: http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/ebola.htm
Ebola and Marburg vaccines created: http://news.bbc.co.uk/2/hi/africa/4612339.stm
HIV and Ebola 'technology' used as delivery systems for Cystic Fibrosis Cure: http://news.bbc.co.uk/2/hi/health/4072626.stm

3 comments:

Anonymous said...

The final paragraph of the ebola blog contains a couple of commonly held misconceptions. 1) The first is that successful viruses don't kill their hosts. This is incorrect: if the host dies after the virus has spread, it makes no difference in the evolutionary success of the virus. There are plenty of extant, lethal viruses around and they simply wouldn't exist if they were unsuccessful. 2) "When the traditional host of a virus is wiped out, the virus will try to jump species, and it will mutate." is wrong on two counts (and notice that it contradicts the author's first assertion): viruses don't "try" to jump species because they've run out of hosts, nor do they start to mutate in order to "try" and jump hosts. Mutations are random and continual (and very common in viruses)and if a mutant strain is capable of jumping hosts, and the opportunity to do so occurs, it could happen any time - it has nothing to do with running out of the original species of host. 3) Viruses don't like "meat". They only need living host cells to co-opt in order to reproduce. Viruses attack everything from bacteria to plants to fungi to insects to humans to whales. And, as far as biomass is concerned, humans don't hold a candles to bacteria, fungi, beetles, ants and plants. 4)"Wipe out their environments and the hosts will die, the viruses will mutate and jump species, and we could be in serious trouble." is simply wrong. Human encroachment into wild places will expose humans to new viruses whether or not the original host is wiped out (e.g. the increasing consumption of bush meat in sub-Saharan Africa), and the threat that viruses will suddenly mutate in response to the original host's decline is baseless.

vlad259 said...

Thanks a lot for your comment, I stand corrected. Very interesting points you raise. Do you think a virus that most often lives in a particular type of mammal is more likely to be capable of jumping to another mammal rather than a plant (for example) ?

Jessica Troisi said...

I hate to be the party pooper, but Ebola was never linked to Kitum Cave. The virus you're thinking of is Marburg, a different, although closely related virus.