The arenaviridae, viruses.
The arenaviruses or the arenaviridae
are a mid-sized virus which are enveloped
and they have a helical capsid,
which you can see on the image in front
of you on the right.
They contain a circular, single-stranded,
negative sense, segmented RNA genome,
which means they must also carry an
RNA polymerase, the RDRP.
They have, due to cellular ribosomes, a
sandy appearance, which you
could also see on the image in
front of you.
To me, it's a very beautiful image,
especially when it's colorized
like this picture.
There are 2 medically important species
in the arenavirus family.
The lymphocytic choriomeningitis
virus, or LCMV, for short,
and the Lassa fever virus, which is
important if you follow many outbreaks
Let's look at the diseases, sorry,
first caused by lymphocytic
The incubation period is 1 to 2 weeks
or 6-13 days, as you see on the
slide in front of you.
And LCMV infused virus --
When it first causes disease starts as a
flu-like illness, so fevers,
malaise, decreased appetite, the
whole 9 yards.
However, the disease then progresses in a
quarter of cases to a full-fledged
So, confusion, headache, photophobia,
sometimes stupor or even coma.
The complications in those patients then,
might even be permanent neurologic damage
due to encephalitis, so cognitive delay,
seizure disorder, etc.
The Lassa hemorrhagic fever virus is
not just in the incubation period, which
is up to 21 days,
but in its whole behavior.
And in fact, if you picture what Ebola
virus and Marburg virus are like,
you'll get a better picture of the Lassa
hemorrhagic fever virus.
So, as mentioned, incubation period, 1-3 weeks,
up to 21 days.
Thankfully, 80% of cases are asymptomatic,
but the remaining 20% will have
fevers followed by evidence of
coagulopathy, of hemorrhage.
So, disseminated intravascular
petechiae in the skin, liver failure,
visceral hemorrhage, so basically, bleeding
out from everywhere.
So, from the eyes, from the nose, the
hematochezia -- bloody stools -- you name it.
So, complications, then,
are myositis, and in those few patients
who are given aspirin,
which would be unusual if they're
already bleeding out,
but if they did receive aspirin, they
might develop further
fulminant liver failure called Reye's
So, the transmission of both
viruses comes from this cute little rodent
in front of you, typically,
mice or sometimes, small rats.
And the virus is excreted in the rat
excreta, so feces, urine.
It is then, when it's aerosolized
ingested or even inhaled by the
In the States and in other
parts of the world where there is
a temperature change,
a classic time to be exposed to LCMV
is during the winter.
Doesn't make sense, right?
Viruses always seem to be like, you know,
respiratory in the wintertime, but
in this case,
the rodents come in from the cold,
and they may be nesting inside
And so, their urine and stool
is far more likely to be inhaled, aspirated,
during the winter months when
Treatment for both viruses.
Well, Ribavirin is an antiviral.
It's a guanosine analogue,
but it is of limited efficacy and is
far more likely
that the patients just require
to get through the infection which
they're dealing with.
In the case of Lassa fever virus,
that is many times going to be extensive
blood products support,
and even sometimes blood
because Lassa fever viruses is
So, 2 different viruses in the same
family, 2 completely
different clinical effects.
And largely, it is based on what
what cell tissue is their target,
in terms of how these 2 viruses proceed.
So, I guess the message of this story is
to avoid rodent urine and feces.