00:01
Then, let's look at the other
end of the spectrum
with the California encephalitis virus.
00:07
California encephalitis is caused
mostly by the La Crosse virus,
which is one of three California
encephalitis viruses
The virus is transmitted
both by the Culex and the Aedes
mosquitoes. And mammalian hosts include
the chipmunk tree, squirrel and fox.
00:24
Human infections typically occur
in the central and eastern United States,
and it is primarily school age
children who are affected by this virus.
00:33
Typically, from July to September.
00:35
Good mosquito months.
00:36
Unfortunately,
the cross virus is the most common cause
of arbovirus induced pediatric
encephalitis in the United States.
00:44
And there are at least 30
to even 120 cases per year.
00:48
Fortunately,
most infections are asymptomatic
and spontaneous resolution is the rule
rather than the exception.
00:55
Mortality is less than 1%.
00:58
Fortunately, this is only a low
mortality infection,
unpleasant to be sure, but spontaneous
recovery is nearly uniform.
01:08
In patients bitten by the infected
Mosquito,
they have an incubation period of maybe
3-7 days, on average 4-5 days.
01:18
And it's right at the end of that incubation
period that one could start to detect
the RNA by an RT, reverse transcriptase, PCR,
especially if one obtains that specimen,
not necessarily just lung tissue but sputum,
and in the also serum, blood.
01:36
Clinical manifestations, that prodrome
with the flu-like illness,
fever, rigors, nausea, vomiting, headache.
01:42
The headache and lethargy is perhaps
more pronounced
in the California encephalitis virus
prodrome than it is with the hanta virus
that we just talked about.
01:53
And overall, the prodrome lasts
less long than it does with hantavirus,
so just 1-4 days.
02:01
Then, the patient develops
progressive drowsiness,
alteration of their level of consciousness,
in fact, becoming very confused.
02:09
Patients, especially children,
will develop seizures
and also focal neurologic findings,
which may be cranial nerve palsies,
and then ultimately, progressing into
coma for about 10% of patients.
02:21
Fortunately, again, the recovery
is spontaneous,
nd most all patients recover without
any significant neurologic sequelae.
02:30
So, 2 different viruses that we've
talked about in this family,
2 completely different clinical
manifestations,
and even with hantavirus, 2 different
clinical syndromes.
02:41
So, a key takeaway from this
particular session is that
viral disease is going to appear
differently depending on its tropism,
depending on its intended target,
and what type of disease or what type
of cell tissue is destroyed by the virus.
02:57
Here ends the lesson.