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outbreak indicate communal rinse tanks may serve as avenues
of infection transmission between divers. When it comes to
rinsing dive equipment in direct contact with divers’ skin and
mucous membranes, such as masks and regulators, instead of
using communal rinse tanks, divers are advised to clean gear
using disinfectants under running water (see sidebar).
Other areas of consideration
Besides rinse tanks, there are at least three additional areas
in which infections may spread among divers: the common,
the rare but dangerous and the feared but unlikely. The most
common infections reported in diving are otitis externa
(swimmer’s ear) and skin infections (impetigo and others).
Fortunately, these can be easily prevented, diagnosed and
successfully treated.
On the other hand, diving or swimming with an open
wound may result in a rare, but often fatal, infection with
Vibrio vulnificus, an opportunistic pathogen commonly
found in warm coastal waters. The Centers for Disease
Control and Prevention receive approximately 150 reports
each year of people infected with V. vulnificus, most by
eating oysters and a few through open wounds.
Some divers fear sinusitis and cystitis (bladder infection).
Indeed, swimmer’s sinusitis has disrupted the careers of
many aspiring athletes. However, it is most often caused
not by microbial infections but by chemical irritation from
chlorine used to disinfect pool water. It does not occur in
ocean swimming. Indeed, some people with chronic sinusitis
maintain that swimming in the sea and flooding their
sinuses with salt water helps, a notion seemingly supported
by an increasing number of ear, nose and throat physicians
who advise patients to use saline sinus rinses to relieve nasal
and sinus congestion. However, it’s important to remember
that the intentional or inadvertent introduction of seawater
into the sinuses could cause infection if the introduced
water is loaded with a sufficient number of pathogenic
bacteria or viruses. It is difficult to come by any such cases
in conventional medicine literature.
The effect of swimming on cystitis in women is a popular
topic of discussion in the media. The prevalence of cystitis is
very high, and in many cases it is recurrent. Each occurrence
often is the result of infection by a new causative microbe.
Chemical irritation from chlorinated water or the prolonged
wearing of a wet swimsuit may enhance the recurrence
of cystitis, regardless of the bacterial contamination of
fresh or salt water. When it comes to cystitis, it may be a
predisposition rather than a specific causation that affects its
occurrence.
Putting it in perspective
While it seems there are many microbial hazards in the sea,
the true risk of serious infection to divers seems negligible.
Most infections that may be occurring among beachgoers,
swimmers and divers probably manifest as diarrhea, but that
is so common among travelers it is rarely linked to seawater.
The two most common infections in divers are ear and skin
infections.
To mitigate risks of infection while diving, regularly
clean and disinfect equipment, avoid polluted waters,
never dive with open wounds (including tooth extractions)
or sores, never rinse your mouth or sinus cavities with
seawater, keep your ears dry, avoid prolonged wearing
of wet clothing and shower after diving. Divers with an
acute infection such as a common cold, conjunctivitis, skin
infection or gastroenteritis are not fit to dive and must take
precautions not to infect others.
AD
PUBLIC HEALTH POLICY
From a public health perspective, monitoring popular
recreational areas for various indicators is one of the
major steps taken in risk reduction. There were more
than 24,000 beach closures and advisories in 2010, the
second-highest number on record. The majority of these
were due to the presence of bacteria. Scientists and
public-health officials rely on several factors to determine
whether risk of infection is elevated in a particular area.
1. Unsurprisingly, the presence of sewage is correlated
with elevated infection rates. Gastroenteritis and
respiratory illness in particular increase with the
degree of site pollution. Pollution with sewage is
generally assessed by monitoring the presence of
enterococci bacteria.
2. High swimmer density is a second factor shown to
increase infection risk. Elevated numbers of minor
ear and skin infections from human-shed bacteria
are observed where swimmer density is high. Skin
granulomas from Mycobacterium marinum have also
been observed. Staphylococcus aureus levels have
been proposed as indicators of exposure.
3. Eutrophication, the increased abundance of algae,
phytoplankton and other marine plants, may be linked
to higher rates of infection by pathogens native to
the marine environment. Runoff from agriculture
and golf courses is a major cause of eutrophication.
Blooms of plankton and algae can promote growth
of associated populations of marine pathogens by
increasing nutrients in the water and providing
microenvironments that favor growth. The prevalence
of Vibrio species has been proposed as an indicator for
measuring eutrophication.
4. Elevated seawater temperature is associated with
increased incidence of shellfish poisoning and cholera.
Remote sensing of sea surface temperature is being
explored, but its predictive value needs further study.
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