Transcripts
DR. TARR:
We are all aware of the cascade
of events that follow infection of a vehicle
containing E. coli 0157:H7 or similar pathogens.
In outbreak analyses there is an
incubation period of a few hours more than three
days, which tends to fall off with a very sharp peak
suggesting that the organism has a fairly
standard pattern of behavior once it's ingested.
There are a few people whom I
do believe really are infected and then show
their first symptoms within 24 hours. The
longest incubation period that I really think is
plausibly related to the ingestion of a
contaminated vehicle was about 11 days, but these
incubation periods have a very sharp distribution
suggesting about three days is the most
common incubation period.
Now it may be, as Dr. Lingwood
was alluding to, that the co-resident bacteria in
the gut or other factors might affect the
epithelial cells such that the consequence is
accelerated, such as Hemolytic Uremic Syndrome,
but the first loose stool on analysis of
outbreaks is three days after the ingestion of
the vehicle.
However, prior to those three
days, in almost every child whose family I've
talked to, or every adult who has had this
infection, in retrospect, something was
not quite right the day before the first episode
of diarrhea. There was lethargy, there was
short-lived fever, there was abdominal pain, back
ache. I remember a child in Tacoma who was a
very rambunctious three year old, and, for the
first time in over a year; he crawled into bed
and voluntarily took a nap the day before his
first loose stool.
So there's something in
retrospect that's not quite right during this
incubation period, perhaps that's the toxemic
burst that injures the vessels. This possibility
is entirely speculative, though.
The diarrhea is the first
symptom that's really easy to pin down as an
objective correlate to the onset of symptoms.
There are very rare cases of children who had E.
coli 0157:H7 in their stool without any episode
of diarrhea. Their stool is full of E. coli,
and they go on to develop HUS. Those are still
unusual. I'm aware of only one case in this
geographic area.
HUS occurs in series at about
day six and a half to day eight after the first
loose stool. The way we count is that day one
is the first day of diarrhea. So when we
encounter a child who is acutely infected we
tell the family that the day five to day nine
window is the most crucial. It would be
extraordinary for a child to develop HUS after
day nine without some indication that things are
not going so well in that window.
In particular, we rarely see a
child that gets completely better, goes home from
the hospital and then presents with HUS a day or
two later. You sort of roll from one point,
one phase of the illness, into the other.
We take a very strict approach.
We think that E. coli 0157:H7 infections are
potentially life threatening and I strongly
encourage hospitalization of all such children.
If for no other reason we encourage hospitalization
for infection control issues.
If one looks at the year 2000
American Academy of Pediatrics Guidebook,
it says a child who is admitted to the hospital
should be placed under contact precautions.
If you look at other germs on
that list, Ebola virus is also listed. So we
treat these children as if they are quarantined
when they come into Children's Hospital. I
personally think it's unfair to send a child
home with a family and say, "good luck," because
of the serious infection control hazard that such
a child presents.
We encourage the very good
hydration of these children almost always with
IV's in this interval and we follow the daily
blood count to make certain that HUS is not
developing.
