Repost re: possible reservoir for Ebola/Marb

[ncel]

> RNA is after all extremely unstable (if you ever
> had to isolate it you know as well). I would say that beside artificial
> conditions in laboratory, in the natural infectivity process, the viral
> envelope is ABSOLUTELY required for a virus to be infective.
 
True for most viruses. But have you ever heard of viroids? They have NO 
capsids, consist only of circular, small, single-stranded RNAs of about 
245-420 nucleotides, yet are quite capable of autonomous replication in 
susceptible plant cells and cause important crop diseases. Most viroids 
are readily transmitted from infected plants to healthy ones by, for 
example, brushing infected leaves over leaves on healthy plants, or by 
driving a tractor through a field with infected plants. So much for RNA
being unstable! Ag workers have demonstrated that dipping of budding 
knives (used in citrus propagation) in ethanol, followed by flaming of 
the knives does not inactivate the citrus exocortis viroid, a free RNA!
As you correctly state, RNA appears to be unstable in the lab, but this is
only because of the ubiquitous presence of RNases on fingers, etc. that 
break down the RNAs.   
Regards from an ETH alumnus.
Ted Diener