- Hello Jeff: Yet, another indication that our rivers
and oceans are dying. If we continue to ignore the signs, we may face
extinction of all marine life and eventually our own.
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- Patricia Doyle
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- ProMed Mail
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- Mycobacteriosis In Striped Bass
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- First, people largely wiped it out through overfishing
and then brought it back with a fishing ban. Now it's being attacked by
a new threat from the bottom of the food chain - a previously unknown single-cell
organism. It will be at least a few years before we know the ending.
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- One of the great successes of nature management is the
restoration of the Atlantic Coast striped bass population. After the commercial
catch of stripers hit a record 14.7 million pounds in 1973, the population
collapsed and a mere 1.7 million pounds was landed in 1983.
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- A federal moratorium on recreational and commercial striped
bass fishing in 1984 quickly turned the population around. By 1990, limited
recreational bass fishing resumed, and in 1995, fisheries regulators declared
the population restored. Now there is a proposal to reopen commercial fishing
of stripers. It's considered a model relationship between man and fish,
and in recent years anglers have caught stripers in numbers and sizes reminiscent
of the old days.
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- There's just one problem: For the past 5 years, they've
also occasionally caught stripers that are visibly diseased. Some have
sores and ulcers on the outside. Most look fine until they're cut open,
revealing ugly granular growths in their internal organs. Fishermen often
don't notice infected fish because they don't cut them open. Usually they
just remove large fillets from both sides of the back and then discard
the rest.
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- The disease is mycobacteriosis, once popularly called
"fish tuberculosis." It was first discovered at the Philadelphia
Aquarium in 1926 and has been seen sporadically in small numbers of fish
since.
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- This time, it is different. It is caused now by a bacterium
-- _Mycobacterium shottsii_ -- which was only discovered in 2001 by the
Virginia Institute of Marine Science while researching an outbreak of the
disease in stripers that started in 1997. And it has already been found
in more than half the fish sampled in the Chesapeake Bay, the main spawning
ground for the Atlantic Coast population of striped bass.
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- Early suspicions are that oxygen-depleting pollution
and a decade of warmer-than-usual waters have stressed the fish and favored
the mycobacteria. If so, then man's recovery plan for the striper may be
incomplete.
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- The new mycobacteria, fortunately, doesn't thrive at
temperatures warmer than 86 degrees, so it can only live on people's extremities
as a persistent rash sometimes called "fish handler's disease."
Scientists recommend gloves, hand washing, and quick release or disposal
of infected fish to prevent it.
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- There is no danger of getting the disease from eating
a striper. One reason is that cooking the fish to 170 degrees for 20 minutes
kills the mycobacteria. Even if they got inside you, mycobacteria would
find your body temperature too high to survive.
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- Scientists think most of the infected fish will eventually
die of the disease, but can't tell when. Too little is known about mycobacteriosis
and its effect on reproduction to forecast whether this will bring about
another crash in the striper population. If so, the great run of migrating
stripers enjoyed by fishermen the past couple of years may only be temporary,
even without the resumption of commercial fishing.
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- And this time, I'm afraid, turning around the population
might not be as easy.
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- http://www.pressofatlanticcity.com/news/columns/120903NATURESWAYDEC9.html
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- ProMED-mail promed@promedmail.org
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- The bacteria that causes aquarium fish mycobacteriosis
is _Mycobacterium marinum_, a bacteria that grows best at temperatures
below body temperature. Individuals cleaning fish tanks with any type of
injury on the hands are subject to a risk of infection, usually of the
skin and soft tissues. Other mycobacteria cause more serious disease in
people, the most significant of which is tuberculosis caused by _Mycobacterium
tuberculosis_. _Mycobacterium shottsii_ may be capable of causing human
disease similar to that caused by _Mycobacterium marinum_, and it would
not be surprising if skin and soft tissue infection occasionally resulted
after handling infected fish.- Mods.TG and DK.
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- Patricia A. Doyle, PhD Please visit my "Emerging
Diseases" message board at: http://www.clickitnews.com/ubbthreads/postlist.php?Cat=&Board=emergingdiseases
Zhan le Devlesa tai sastimasa Go with God and in Good Health
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