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Might Food Become a Vehicle for Tropical Disease?

PROVIDENCE–It’s highly unlikely, but if high in an African mango tree a bat dropped its guano on fruit and it was harvested and went unwashed on a 747 to America, you could end up with a deadly tropical foodborne illness characterized by bleeding through the eye socket.

These are the possibilities that are considered at the International Association for Food Protection, which is meeting this week at the Rhode Island State Convention Center. It’s where food professionals come to learn about the World Health Organization’s (WHO’s) Global Foodborne Infections Network, or PulseNet International, which keeps track of threats most of us don’t even want to think about.

It’s where you come to learn about “unusual Salmonella serotypes” emerging out of Southeast Asia or new foodborne pathogens like E. coli O104:H4. These are the sessions attended by the people from the Centers for Disease Control and Prevention in Atlanta who will show up in bug suits if anything really goes badly in America.

Thankfully, it all ends with Dr. Daniel Bausch, associate professor of tropical medicine at Tulane University, telling us there is not really that much to worry about.   Hopefully. His talk is called  ”Foodborne Viruses–What Else is Out There?”

Bausch provided more assurance than alarm regarding the likelihood that any of us will be stuck by an exotic and scary foodborne illness. Yet he also welcomed us to his world.

He’s seen what these diseases can do. Bausch was on the SARS team sent to Vietnam ten years ago. Severe acute respiratory syndrome (SARS) is caused by a virus from small mammals originating in China. The SARS virus can then spread like the common cold. It cases a pneumonia so severe that it can lead to death.

There are a number of exotic pathogens out there that in the right circumstances may be spread by food or water, Bausch said. Among these are Lassa fever, Rotavirus, Ebola, Hepatitis E and Nipah virus.

The following is a brief description of each of them:

- Lassa fever: An acute viral illness, endemic in West Africa, infects 100,000 to 300,000 a year, causing 5,000 deaths. Reservoir or host for virus is a small rodent.

- Rotavirus: A double-stranded RNA virus, it is he most common cause of severe diarrhea among infants and children. Controlled in U.S. by vaccine, there are at least 450,000 cases annually worldwide.

- Ebola: A virus causing Ebola hemorrhagic fever (Ebola HF) is a severe, often-fatal disease in humans and nonhuman primates (monkeys, gorillas, and chimpanzees) that has appeared sporadically since its initial recognition in 1976.

- Hepatitis E: Liver disease caused by the hepatitis E virus: a non-enveloped, positive-sense, single-stranded RNA virus. There are 20 million hepatitis E infections, over three million acute cases of hepatitis E, and 70 000 hepatitis E-related deaths.

- Nipah virus: It causes inflammation of the brain (encephalitis) or respiratory disease.

These are among 51 foodborne zoonotic virus illnesses.

Some of these might not be recognized for their potential as foodborne illnesses because they do not involve the usual gastrointestinal symptoms. Bausch says its likely the exotic diseases would be recognized by medical professionals, but some would require confirmation by the most secure biosecurity level 4 laboratory.

“These things can be out there,” Bausch says. “Just because you haven’t seen it in your area does not mean it does not exist.”

Bausch said most people are surprised with how simple it is to inactivate some of the world’s most deadly viruses. He said if he had the Ebola virus, it would take some bleach and about 15 minutes to have it safe for disposal. (Formal procedures would require much more, like evacuating the entire building.)

One example of a “foodborne” Ebola outbreak he gave involved 16 African boys who come across a dead chimp and proceed to eat the meat raw without knowing it is infected with the virus. In short order, 14 boys died, but Bausch says because of “time and distance” the threat is limited to the group

“Mostly we do not see Ebola as a foodborne illness except in such special circumstances,” he said.

The rodents in West Africa that carry the Lassa virus mean it also can become a foodborne disease. “Everybody has these rodents around their houses,” he says. But Lassa fever remains in the area near the virus reservoirs-the rodents.

For Nipah virus, where the pigs in Malaysia are apparent reservoirs, large hog operations owned by China may be a contributing favor.

In the case of Hepatitis E, wild boars were originally the virus’s reservoir, but there are now indications domestic swine may be serving as a reservoir.

As for bioterrorism, Bausch said “the answer is not a definite no.” He did say it’s difficult to come up with a scenario that does not have a some fatal flaw. It is not as simple as putting a dangerous virus in a crop duster.

A greater cause for fear might be prion diseases because they do not react to applications of things like heat, which can kill viruses.

The whole topic of tropical diseases that might become foodborne might be a little out there. But did you know you can also die of Ebola without ever losing any blood?

© Food Safety News
  • Jill

    One man’s dreadful disease is another woman’s scintillating biodiversity. In the exciting new theory of agroecology we earnestly encourage all biodiversity, we covet it above all else. We could never condone introducing any chemical, such as bleach (oh, ick!) to unbalance the exquisitely nuanced natural interplay of myriad species all more significant, each more deserving of life on this singular planet than any ordinary human being. Indeed, humans are the only expendable species. All others are inviolable, if only common people could learn to accept that the world would be a much nicer, much more sustainable place for the rest of us.