Viruses and parasites that should keep you up at night
foodsafetynews.com, by Dan Flynn, July 12, 2017
TAMPA, FL — Foodborne Hepatitis A, once accounting for only about 4 percent of cases, reached 20 percent by 2016
Cyclosporiasis, the intestinal illness caused by the microscopic parasite Cyclospora cayetanensis, recognized only in 1979 and after that only among travelers, has become commonplace in the United States.
And other emerging virus and parasites are leaving few places to escape in an ever smaller world, according to three distinguished experts on dangers that include that include Hepatitis A, parasites like Cyclospora, and other nasties with names so long they defy spellcheck — like haycocknema perplexum.
The experts, the Rosa Pinto of the University of Barcelona, Richard Bradbury of the Centers for Disease Control and Prevention, and Doriliz De Leon of the Food and Drug Administration, left an International Association for Food Protection (IAFP) audience feeling a little creepy Tuesday after their presentations on emerging viruses and parasites.
Pinto, who has charted recent Hepatitis A outbreaks across Europe and North America, showed how stereotypes 1A and 1B have so far been most common around the world while the more virulent stereotype 3A has remained largely confined to the subcontinent of India.
Vaccinations for Hepatitis A have been effective in the areas they’ve been employed, including Pinto’s home area of Barcelona, which in a recent outbreak had the fewest number of cases of any other major area of Spain.
The CDC has hired emerging disease expert Richard Bradbury to run defense against the parasites that are invading the U.S. Top on the list, according to Bradbury, is Cyclosporia.
Symptoms are “prolonged and watery diarrhea.” Bradbury said “It’s pretty bad.”
Cyclospora cayetanensis was first identified in 1979, less than 40 years ago, and Bradbury said there are still “some bits” about the parasite that we do not understand. These include, he says, Cyclospora’s life-cycle range.
“This a big issue in the U.S.,” said Bradbury, adding that the impression that the parasite is only a border issue is likely due to the fact that it is not being detected yet further north.
He feels pretty good about that prediction because Cyclosprora has popped up as far north as Sweden.
He says for a parasite, found relatively recently in Papua New Guinea, its spread to areas of the world has been impressive and is not likely over. And Cyclospora is far from the only threat.
Anisakiasis is a parasitic disease caused by anisakid nematodes — worms — that can invade the stomach wall or intestine of humans. The transmission of this disease occurs when infective larvae are ingested from fish or squid is eaten raw or undercooked. In some cases, the infection is treated by removal of the larvae via endoscopy or surgery.
If you’ve got it, your best hope for Anisakiasis is “coughing it up,” according to Bradbury. Unless expelled, the worms can cause severe allergic reactions from the esophagus through the digestive system to the rectum.
Another emerging parasite, Human gnathostomiasis, is caused by several species of parasitic worms in the genus Gnathostoma. The disease is found and is most commonly diagnosed in Southeast Asia, though it has also been found elsewhere in Asia, in South and Central America, and in some areas of Africa.
“In this case people really do have parasites crawling under their skin,” Bradbury said.
People become infected primarily by eating undercooked or raw freshwater fish, eels, frogs, birds and reptiles. The most common manifestations of the infection in humans are migratory swellings under the skin and increased levels of eosinophils in the blood. Rarely, the parasite can enter other tissues such as the liver, and the eye, resulting in vision loss or blindness, and the nerves, spinal cord or brain, resulting in nerve pain, paralysis, coma and death.
Bradbury said when the worms enter the eyes and brain the victim is in “real trouble.”
Another species that is increasingly becoming a problem is Haycocknema perplexum, a muspiceoid nematode native to the island of Tasmania, of the nation of Australia. It is a dangerous parasite to humans, and its infection can be life-threatening. Bradbury suspects its spread is due to adventurous travelers wanting a taste of kangaroo and/or koala bear meat.
As for combatting emerging virus and parasites, that job falls mostly on the U.S. Food and Drug Administration. De Leon said new enforcement provisions of the Food Safety Modernization Act (FSMA) are going to help the agency in the battle.
Since 2012 FDA has been watching imported cilantro from the Puebla, Mexico, area because of consistent contamination with Cyclosporiasis. The single-cell parasite has been crossing the border every year since then. The CDC reports 38 cases of cyclosporiasis from Mexican cilantro in 2013, 26 in 2014 and 90 in 2015.
De Leon said FDA personnel has been working in Mexico since 2012 with the country’s food safety agencies to address sanitation issues. She said the Puebla area is not one of the ares that FDA has avoided over security concerns over because of take-over by Mexican criminal cartels.
She said she is hopeful that cyclosporiasis cases from the area for 2016 will be down. However, that may not be the case as CDC reports 384 people with laboratory-confirmed cases of cyclosporiasis in 2016, with 134 of the illnesses originating in the U.S. A county background the for the others was not readily available.
De Leon did say the 2016 Hepatitis A outbreak involving raw, frozen, imported scallops, which sickened 292, caused Sea Port Products Inc. to recall the product, ultimately had a positive post script.
This year, she said, the supplier has stepped forward to recall frozen tuna for Hep A contamination based on its own testing and recalled the product. This time no illnesses were reported.
The trio of emerging disease experts spoke on Tuesday to the International Association for Food Protection’s annual meeting, which continues today at the Tampa Convention Center.