ryan at mbcf.stjude.org
ryan at mbcf.stjude.org
Thu Jul 20 11:04:32 EST 1995
In article <3ujgn9$cb1 at newsbf02.news.aol.com>, edregis at aol.com (EdRegis) writes:
> Anyone know anything about para-influenza virus?
Hi Ed, how are you? Yes, I can help with this...
> Is it a sub-type of
> influenza virus?
NO. Flu and paraflu do share some features. The both use a negative-sense
genome replication strategy (same as rabies, measles, ebola, others). Flu and
paraflu also have virus proteins which are approximately analogous: one protein
to bind tightly to genome RNA, others to attach to this ribonucleoprotein
complex for purposes of RNA synthesis, others to stick out from the virus
surface and mediate attachment to new host cells. Proteins with similar
functions may have similar names, and in general have similar biochemical
properties (RNA-binding proteins are basic, virus-surface proteins are
BUT these viruses are not closely related. Amino acid sequences for analogous
proteins diverge widely. Perhaps more fundamentally, paraflu uses a
single-piece genome while flu has approximately the same amount of RNA divided
among 8 separate segments. This difference is the best indicator of the
relatively great evolutionary distance between these two types of virus. Based
on replication strategy, parainfuenza viruses are more closely related to
measles or ebola than to influenza.
> What symptoms does it cause?
Here parainfluenza is very similar to flu (hence the name). Respiratory tract
infections, both upper (less severe) and lower (more severe). Common-cold-type
symptoms when in upper RT, bronchitis/bronchiolitis/croup/pneumonia symptoms
when in lower RT. Serious disease usually in young kids only, whose small
airways don't allow for much constriction before loss of airflow becomes a
Note that while parainfluenza infections are generally limited to the
respiratory tract, this is not true of all members of the paramyxoviridae.
> When first discovered?
The murine strain of parainfluenza type 1 virus (Sendai virus, aka
hemagglutinating virus of Japan [ HVJ ]) was the first of this type to be
isolated. It is a mouse respiratory pathogen, causing symptoms very similar to
those caused by human-specific virus strains. The human parainfluenza viruses
(several types) later were isolated from pediatric respiratory infection
patient samples in the mid-1950's. I believe the seminal publication for human
parainfluenza viruses is:
R.M. Chanock (1956) J Exp Med _104_ 555-576.
> Many thanks,
> edregis at aol.com
Best regards, Kevin.
Kevin W. Ryan
Department of Virology & Molecular Biology
St. Jude Children's Research Hospital
Memphis, Tennessee 38101-0318, U.S.A.
phone: (901) 495-3411
fax: (901) 523-2622
Internet: ryan at mbcf.stjude.org
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