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Killer Virus 'From Paramyxoviridae Family'
texchanchan writes "Yahoo story about the microbe that's been killing world travelers being isolated and identified as a 'paramyxoviridae' virus (not a bacterium. Simple page on the difference.) Here are pictures of similar viruses (Rinderpest, ugh! sounds as bad as anthrax) from the Big Picture Book of Viruses."
I would have to assume you're joking. RNA virili and bacteria are far more prone to mutations in the genes. Why hasn't AIDS been cured? It's an RNA virus; it mutates too often for a standard vaccine to work. The same goes for this virus. A vaccine may be possible (at least one AIDS vaccine is in some phase of clinical trials), but it is not likely in the immediate future.
This is not particularly surprising: viruses in that family cause a lot of "common colds" and other URIs (among them, parainfluenza is in that family). See here and here.
Could you imagine an influenza strain that spreads through the air and causes chronic lung damage (and lots of deaths)?
We don't have to imagine it -- it's already happened. Check out the Influenza Pandemic of 1918.
One quote from the link:
"The effect of the influenza epidemic was so severe that the average life span in the US was depressed by 10 years."
It is related to Canine Distemper Virus, and the Newcastle Virus famous for infecting chickens.
The "service pack" for Newcastle is usually total destruction of all the birds in the area near the infection. Probably because vaccinations cost more than chickens do.
It would be interesting to see if innoculating people with one of these (or Parainfluenza Virus) would act as a vaccine, like using cowpox virus to prevent smallpox.
The Phocine Distemper virus that is killing seals is also related. Does Canine Distemper vaccine work to protect seals from Phocine?
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This family of viruses (paramyxoviruses) are very closely related to influenza viruses- in fact, influenzas belong to the family orthomyxoviridae. Myxo, by the way, comes from the Greek for "mucus"- appropriate given their tendency to cause respiratory tract infections.
Both families are single-stranded "antisense" RNA viruses- the RNA strand is complementary to a coding, or "sense" strand of mRNA that it acts as a template for. It should be noted that while these are RNA viruses, they are not retroviruses, as some other posters have suggested- no reverse transcriptase, no DNA stage- instead of hijacking the cell's transcription machinery like HIV, myxoviruses are slightly more considerate guests- they come packing their own RNA polymerase proteins. The RNA polymerase makes a gigantic number of of sense mRNA from the antisense strand. Once these get made, the virus stops being a considerate guest in the cell- the mRNAs head over to the ribosomes in the cell and get translated into proteins just as if the cell's genome had produced them. These are of course viral proteins however- new capsids (protein envelopes), new polymerases, new glycoproteins. This is the part where it really starts to suck for the cell- the original viral antisense mRNA gets replicated many times, and then gets packed into the newly made viral particles. The viruses then lyse (kill) their host cell and then spread out an move on to a new cell. This takes about 20-30 minutes from fusion with the cell to lysis usually.
Both ortho- and para- myxovirus families respond to a characteristic test called hemagglutination, which is pretty much what it sounds like- a glycoprotein on the surface of the virus causes red blood cells to clump together. The major difference between the orthomyxoviridae and paramyxoviridae families is simply a matter of genome arrangement- ortho viruses like the influenzas have their genomes cut into several different smaller segments inside the virus, while the para viruses like measles, rinderpest, and our mystery illness have a single segment.
It should be stressed that genome comparisons are of limited help at the level of families- all the single-stranded antisense RNA viruses have pretty much the same structure, but they code for quite different glycoproteins (these are sugar-protein hybrid molecules on the surface of the virus). Glycoproteins are both the source of host recognition- they bind to specific receptors on a cell (these receptors are often, but not always, unique to the cells of a species)- and the agent that kills the cell. In the paramyxoviruses, remarkably these two functions (fusion and lysis) are carried out by two linked subunits on the same glycoprotein.
The variety of glycoproteins these RNA viruses have produced have made them incredibly diverse- they infect plants, animals, humans, they cause all manner of symptoms. The paramyxoviruses, for example, have members which result in mumps and measles, and then others that cause pneumonia. A closely related family (also ss antisense RNA) are the rhabdoviruses, some of which infect plants, and one of which causes rabies. Another antisense ssRNA family are the filoviruses, which tend to have rather toxic glycoproteins- members include Marburg and Ebola.
While it is a relief that the virus causing this deadly outbreak of pneumonia has been isolated, and catalogued in relation to other viruses, it should be noted that finding this relation may be of little use, given the nearly infinite variety displayed by even its closest relatives.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
>>I'm really, really impressed at how focused the international health community can be, even when separated by political boundaries and vast geographical boundaries. Lets hope they keep up the pressure to keep this contained.
You know, I'm really really unimpressed seeing that no one cared for months until a few americans started getting sick.
Try not to decieve yourself. The international health community still only gives a **** if it affects the people giving them the most money.
The media is now reporting that most of the cases from Hong Kong all seem to have been exposed at a particular hotel floor... Here's a link to the story.
It also occurs to me that if one was drowning, yelling "Help! I'm drowning and I lost my bikini top" would probably be m