Wednesday, December 16, 2009

ON RARE DISEASE AND POLICY

Many moons ago your host attended grad school in Pennsylvania, dutifully working his way toward a Ph.D. My work was on a microbe few people had heard of at the time: Vibrio vulnificus.

Today, over twenty five years later, all the oystermen and oyster eaters on the Gulf Coast know about it.

The lab I worked in specialized in studying the protein products of marine vibrios. And I chose to work on what was thought to be a novel example of them, looking for a protein -- an enzyme -- which dissolved collagen.

Why?

Because collagen is present in all the connective tissue in your body.

And Vibrio vulnificus caused a truly catastrophic illness in a small number of people, a systemic infection that punched holes in the body, from the inside out.

To do so, to cause ulcerating holes and sores to form through the flesh, it had to produce something that ate away at human tissue.

Pictures of the real life result of this fit for disturbing your lunch are here.

I reasoned, correctly as it turned out, that Vibrio vulnificus had to produce an extracellular collegenase -- an enzyme which dissolved collagen. When it was applied to experimental assay plates filled with a flesh-like gel of pure collagen held at body temperature, it created empty pools of peptides -- protein fragments -- and water. This was one way to quickly check for its presence and relative activity.

The paper I wrote defining the discovery is here should you like to see the hard science of it.

Since it was a human pathogen and it did produce a fatal illness, initially a good bit of thought was given to whether or not to bring it into the lab.

However, the literature that existed on it at the time seemed to indicate that the organism primarily erupted in individuals with pre-exsting severe underlying illnesses, primary diseases which depressed immunity. After mulling it over I thought the risk posed by the organism to be small and acceptable.

But with living things like bacteria, there is always the possibility that when you are exposed to it in a variety of ways, interesting stuff can happen. Growing large quantities of Vibrio vulnificus so that collegenase could be harvested and characterized ensured conditions like this would arise. This is always a risk in the hands-on study of those organisms which cause human disease. I am sure that no matter how careful we were in the lab, at one time or another I was exposed to greater than natural concentrations of Vibrio vulnificus.

Here I am, right as rain! Too bad, eh?

In October of this year oyster fishermen in the United States were given a rude shock when the FDA moved to ban their oyster catch through the summer months.

Vibrio vulnificus, our lab originally found, was surely present in a great many things -- including oysters -- in inshore Gulf Stream waters, pretty much all the time. But its concentrations were probably greatest during the summer months when the water was warmer and more conducive to fast growth. And this coincided with when vacationers and locals like to eat lots of raw oysters, although one could occasionally contract the infection through cuts or open wounds, too.

In fact, if you've vacationed regularly at resorts on the Gulf Stream in the summer you've probably come into contact with Vibrio vulnificus .

"The 'safetycrats' at the Food and Drug Administration were ready to crack down on Vibrio vulnificus, a bacteria that infects oysters, by imposing costly new rules on the oyster industry," opined the Mobile Register in mid-November.

"Millions of people consume raw Gulf oysters without suffering any ill effects. But people with diseases that weaken the immune system are vulnerable to the bacteria. About 15 people a year die [from V. vulnificus infections] after eating raw oysters."

The FDA used a magnifying glass on Vibrio vulnificus, said the newspaper.

In the Nineties, restaurants and supermarkets were pressed to display signs about the hazard of eating raw oysters. Although V. vulnificus was not mentioned on these signs in southern California, the organism was the reason for them.

But no one pays attention to such signs in America.

"This prompted the FDA to haul out a regulatory 'sledgehammer' ... and prepare to take a swing at the oyster industry," continued the Mobile newspaper in mid-November. "The FDA wanted to ban sales of raw oysters from April to October, unless the oysters were sterilized with special equipment."

The FDA, due to a rather obvious and logical response -- a vigorous protest at the state level -- backed off on this plan.

"FDA officials [said] that education hasn't worked," reported The (Baton Rouge) Advocate, the same month.

"In 2001, the Interstate Shellfish Contamination Conference, formed in 1982 to promote shellfish sanitation, embarked on a campaign to teach consumers about the dangers, said Mike Taylor, an FDA senior adviser ..."

Interestingly, when DD published on Vibrio vulnificus, it was the same year as the formation of the Interstate Shellfish Contamination Conference. I can't emphasize enough that there was no particularly noticeable interest in the science of the microorganism back then. The disease it caused was equally deadly and horrible, its incidence about the same. The government had no interest in it. The FDA did not appear to care. No one did, really.

"The conference - which is made up of academic, industry and state and federal officials - agreed that if the campaign didn't work, that the new policy would be the next step, Taylor said," continued The Advocate, in explaining how the FDA came to its initial -- now rescinded -- plan to ban.

"The policy would affect about 25 percent of the harvest, Taylor said."

"There has not been a significant reduction of people getting sick and dying," Taylor told the newspaper. "There are lives at stake here. It's not a stomach ache from salmonella. It's a deadly disease."

Indeed it is not a stomach ache. But having worked with more Vibrio vulnificus daily than most people will come in contact with in their entire lifetime, I can tell you the FDA man did misrepresent the nature of the risk.

"Taylor pointed to California, which requires the treatment of Gulf oysters. Over a 10-year period beginning in 1991, the state had 40 deaths," reported the Baton Rouge newspaper. "The number has been reduced to zero, Taylor said."

That came to about four deaths a year. Stamped out through sterilization.

"Throughout the South, and particularly in Louisiana, where two-thirds of the nation's oysters are harvested, irate legislators, oyster farmers and connoisseurs told the government to back off: If people want to risk their lives for a plate of cold oysters, fresh lemon juice and just a dash of hot sauce, then that's their business," the Los Angeles Times opinion page reasoned, trying to be informative, on November 15. "Processing [oysters], they said, ruins the taste."

"More to the point, the FDA's mandate, they said, would jeopardize 3,500 jobs and destroy the livelihood of generations-old family businesses by requiring them to invest in cost-prohibitive technology. Within days, the FDA canceled the ban on untreated oysters. For now."

However, the Times went on to insinuate that California knew how to do things better, an argument that didn't hold a shake flask's worth of Vibrio vulnificus.

"The FDA ... plans to study the economics of processing to help the [shellfish] industry adapt," it continued. "Although treated oysters may alienate some purists, other diners may be reassured and give raw oysters a shot. Also, markets currently closed to warm-weather Gulf Coast oysters because of the dangers may open.

"As for public health, the best case study may be California. In 2003, after 40 deaths over a 10-year period, the state required warm weather Gulf Coast oysters to be processed. Since then, there have been no Vibrio deaths, and some oyster businesses have adapted to the new rules. But one thing is clear: For all the talk of cooperation, the FDA's ultimate goal is to help the industry 'transition.' Because the one argument the Gulf Coast oyster industry has not successfully made is that the deaths of those 15 people a year don't matter."

Actually, the degree of risk is what should be argued. There is no way to predict who will contract a very rare but potentially fatal infection from eating oysters containing V. vulnificus, only that it will happen -- somewhere -- as long as raw oyster eating is something people greatly enjoy. And that in fifty percent of these cases the end will be gruesome.

Eat raw oysters. You might put your guts out, kid, maybe. But from my experience, probably not.

0 Comments:

Post a Comment

<< Home