Since the massive Hepatitis A outbreak at a Pennsylvania Mexican food restaurant chain last month, the green onion has become the loneliest vegetable in the bin.

The suspected cause for over 600 infections and three deaths from hepatitis A (HAV) was contaminated raw green onions imported from Mexico. Most of the green onions were uncooked or undercooked and were used as garnish or as a condiment in the salsas and soups.

And that wasn't the first recent outbreak where South-of-the-Border scallions were suspected as the bad guys. Tennessee, North Carolina and Georgia got hit in September.

But, don't cry for the onion. They don't cause liver infections. It's the unsanitary conditions that exist where they are picked, then transported and prepared. HAV comes from people, not plants. Fresh produce is just the courier.

Handle With Care

The detective work starts in the field-literally. HAV is known as a "fecal-oral" transmitted virus. "Think of the conditions in the fields for these workers, and it starts to make sense," says Zuber D. Mulla, Ph.D., assistant professor of epidemiology in the Center for Infectious Diseases at The University of Texas School of Public Health at Houston, El Paso Regional Campus.

"Green onions require a lot of handling during harvesting and packing. Hundreds of people are out there, often children, without toilets in the field. The fields become contaminated by human waste or by poorly washed hands. The vegetables are hand-picked, then passed through several other hands, then rinsed with possibly contaminated water from the same field, and packed in possibly contaminated ice."

Then, they arrive in bulk where there are multiple opportunities for intermingling of tainted produce with untainted foods. The knife that chops the raw, contaminated scallions is used to mince the good ones. They are then sprinkled atop a perfectly safe salsa or soup.

"The problem is," Mulla says, " the only effective way to ensure that fresh produce is uncontaminated is to cook it thoroughly, like boiling it. " Washing it off with simple water won't do it. And freezing it just preserves it. Scallions are one of those foods that are often served raw.

Though all raw produce can be tainted, vulnerable foods also include, sadly, the crown jewel of fruits: the strawberry.

"Actually, food-borne hepatitis A outbreaks in the US are rare, " says Mulla. Usually, he explains, hepatitis A is transmitted person-to-person, either through poor hygiene, unwashed hands after using the restroom, oral-anal contact during sex, or traveling to countries where HAV is endemic, such as the Middle East, Africa or Mexico.

Since the virus is shed in the feces, good hand hygiene is the best daily defense against contracting it. Some states require HAV vaccines for kids starting at age 2. Adults are invited as well, but not required.

Hepatitis A Facts

Persons with hepatitis A range from totally asymptomatic to miserable. Children, however, often don't present signs of disease at all, yet they can infect a household through diaper changes and poor hand-washing.

If symptoms are present, the onset is quick, may include fever, fatigue, loss of appetite, nausea, abdominal discomfort, bright yellow-to coffee-colored urine, and jaundice (yellowing of the skin and eyes). 

Symptoms usually last less than two months, but can persist up to six months. The average incubation period for hepatitis A is 28 days (range: 15-50 days ). Which means: if Aunt Ida used tainted produce at her Thanksgiving meal, you might not feel anything until New Year's, or even the Super Bowl.

Though HAV is not usually fatal, nor does it cause permanent liver damage (like hepatitis B can) it can seriously harm persons with chronic liver disease or who are immune-compromised.

Being viral in nature, there is no treatment for HAV, other than supportive measures for comfort or complications to the liver. The good news is, you can't get it twice.

If you think you have been exposed but are not symptomatic, you can receive an immune globulin injection and receive fairly good protection if it is administered in the first few weeks of exposure. For prevention altogether, you can ask about the vaccine.

Until the disease detectives-epidemiologists such as Mulla-have sleuthed their way to the source of this outbreak: cook your green onions instead of serving them raw and always wash your hands thoroughly before preparing food. "We can't live in fear-these outbreaks aren't common. But we can control our own hygiene, thus cutting done the chance of exposing others."

For information on Hepatitis B, C, D, E, go to the Centers for Disease Control and Prevention link: www.cdc.gov/hepatitis/index.htm

Last Updated: 12-18-2003

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