VIRUSES
Most of these
viral pathogens
cause symptoms
approximately
36 to 48 hours
after contact with
an infectious
individual. The
most common
viruses that cause
cold symptoms are
the rhinoviruses and coronaviruses. These viruses are
spread from person to person by respiratory droplets
and do not generally cause severe illness. They can,
however, affect dive plans by making it difficult to
breathe through a regulator or inhibiting a diver’s
ability to equalize pressure in the ears or sinuses.
While over-the-counter medications may ease
symptoms, they may also have problematic side
effects or wear off at inopportune times. Some over-
the-counter preparations are advertised as curative,
but the U.S. Food and Drug Administration (FDA)
generally classifies these as nutritional supplements
because there is no proof of their effectiveness.
Most doctors trained in dive medicine recommend
against diving for anyone who has an acute illness —
especially if the illness is serious enough to warrant
the use of medication.
One problematic group of respiratory viruses is
those that cause influenza (“the flu”). Influenza is
characterized by respiratory symptoms, fever, body
aches and general malaise (i.e., feeling just plain
lousy). While the symptoms are more severe than
those of the common cold, the treatment is pretty
much the same: Address the symptoms. There are
effective antiviral medications that are sometimes
prescribed for patients with the flu, but in otherwise
healthy adults most health-care professionals opt to
let the infection run its course. There are fatalities
from influenza every year, but these most often
occur in the very young, the very old and people
who suffer from significant chronic diseases.
Viruses that affect the gastrointestinal tract
cause more serious and unpleasant symptoms.
The previously mentioned norovirus group is the
prototype for these pathogens. These viruses are
spread by person-to-person contact as well as
contact with objects upon which there are droplets
that contain the infectious organisms. Such objects
include doorknobs, computer keypads, telephones,
exercise equipment and dive gear such as regulators,
masks and snorkels.
Most of the large-scale outbreaks that made the
news in the past few years were due to these viral
GI pathogens. The symptoms typically include
nausea, vomiting, fever and diarrhea. Severe cases
pose a risk of dehydration and loss of critical
electrolytes. Otherwise healthy adults generally do
just fine with fluid replacement and treatment of
symptoms, but children, the elderly and people with
other significant medical problems may require
more aggressive medical care. Intravenous fluids
and replacement of electrolytes may be required,
and prescription medications can be employed to
combat the nausea and vomiting.
BACTERIA
Occasionally, bacterial pathogens rather than viruses
cause severe outbreaks of gastroenteritis. Bacteria such
as salmonella and shigella wreak havoc directly on the
cells that line the intestines. Salmonella typically causes
fluid loss through watery diarrhea, while shigella can be
more invasive, causing bloody diarrhea. Both of these
bacteria can cause serious illness.
Most people are aware of the effects of the
bacteria E. coli — it is the primary reason some
restaurants won’t serve rare hamburgers. There
are various types of E. coli, some of which behave
more like salmonella and others more like shigella.
Treatment for infections caused by these bacteria
is very similar to treatment for viral gastroenteritis,
but in some cases an antibiotic may be helpful. The
means of transmission are identical.
Bacteria that create toxins can cause GI symptoms,
and ingestion of the toxin causes illness. The bacteria
90
|
FALL 2014
Before traveling,
visit
travel to learn what
vaccinations are
recommended for
the areas you plan
to visit.
Opposite, from left:
Microbiologists use
cultures to help
diagnose illnesses.
Frequent hand
washing reduces
your risk of
contracting
communicable
diseases.
STEPHEN FRINK
