December 31, 2010

Seafood safety concerns for those with liver disease

Posted: 12/29/2010 10:44:26 PM PST

Last week (hallelujah!), there was progress in Washington, D.C. After a Senate vote in November edged us one step closer to better food safety in the U.S., the House of Representatives also approved the bill. The reform is long overdue.

Remember, if you will, recent nationwide outbreaks from eggs, peanuts, and spinach. These cataclysms killed more than a dozen people and sickened thousands more.

In the future, new laws enabling the FDA to recall tainted food should help contain outbreaks; more money for inspection here and abroad will nip others in the bud.

Nonetheless, reducing food-borne illness to the lowest possible levels also requires consumer education and collaboration. Above all, consumers with underlying disease need to go the extra mile to protect themselves. Why? Statistically and biologically, they are the ones with the worst outcomes from food-borne blights.

A poignant case from the 1990s illustrates my point.

The patient was a 41-year-old Central American with long-standing liver disease due to hepatitis C. The good news? She was well-insured, had excellent physicians, and followed medical advice to a T. The bad news? She did not realize her risk of illness from eating raw or undercooked seafood.

And so, on a warm afternoon in early fall, a relative went to a local fish store and purchased oysters. Within an hour or two, the entire family shared in the feast.

One day later - although no one else was sick - the patient started running a fever. Then her eyes turned yellow and her blood pressure plunged.

But it was her skin that ultimately showed telltale signs of a unique and deadly invader. By the time the patient reached the hospital in shock, large hemorrhagic blisters covered both of her legs. This distinctive finding - along with cultures of blood and skin fluid - clinched her diagnosis. She had a widespread infection due to vibrio vulnificus, a marine bacteria.

So the oysters she ate were spoiled, you may be thinking about now. Well, yes - and no. Since they often live in oyster beds and do not come from human or animal waste, vibrios aren't contaminants of the usual sort; moreover, they do not cause altered appearance, taste or smell of affected seafood.

To a marine microbiologist, they are closer to normal seawater "flora" that thrive in warm-ish temperatures, thus accounting for the time-honored adage: "Only eat oysters harvested in months containing an "R." (Translated: "Brrr" months.)

Agents within the vibrio tribe that cause human disease include cholera - a toxin-bearing pathogen currently plaguing Haiti. Of the non-cholera species, V. vulnificus is the worst. Even in healthy people, quick dips in ocean water containing V. vulnificus can lead to dangerous skin infections if the bacteria breach minor cuts and scrapes.

In people with damaged livers, V. vulnificus is even scarier. Within 36 hours of ingestion, it not only invades their bloodstream, it often spreads like wildfire to their skin, producing deep, necrotic ulcers resembling third-degree burns. In this scenario, despite excellent care and antibiotics, fatality rates often top 50 percent.

Now for a special twist. During the same two-year period in which the patient described above suffered (and thankfully survived) V. vulnificus infection, 10 of 11 cases reported in Los Angeles County occurred in Spanish-speaking residents with chronic liver disease. As a result, even though California was already the first state (as of 1991) to require English and Spanish-language signs regarding the potential health risk of eating oysters from subtropical waters, the campaign was stepped up.

Today, if you walk into a seafood restaurant or store and do NOT see a sign that opens by stating, in English and Spanish: "Eating raw oysters may cause severe illness and even death in persons who have liver disease (for example, alcoholic cirrhosis), cancer or other chronic illnesses that weaken the immune system. ... " you should not hesitate to mention the lapse to a manager.

Of course, another hazard of shellfish and mollusks (in other words, oysters, clams and mussels) is hepatitis A, the most serious viral infection associated with seafood consumption. Contamination is most likely when human sewage pollutes an aquaculture site. The largest outbreak to date (affecting almost 300,000 people) occurred in China in 1988. The victims all ate clams from a sewage-sullied growing area.

Since hepatitis A virus targets the liver, it is a special threat to people with pre-existing liver disease. Fortunately, they can be well-protected by a safe and effective vaccine.

Dr. Claire Panosian Dunavan is an infectious disease specialist and a professor of medicine at the David Geffen School of Medicine at UCLA and a resident of Pasadena. She can be reached at


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