Globally, however, foodborne parasites affect the health of millions of people annually, causing debilitating and potentially deadly conditions and sometimes living within humans for years.
A new report from two agencies within the United Nations ranks 24 foodborne parasites according to their impact on global health, identifies the foods of greatest concern associated with those parasites, and discusses strategies for protecting against them.
Here are the top 10:
1. Taenia solium (pork tapeworm): Most commonly found in raw or uncooked pork but also in fresh produce. Symptoms are often mild or nonexistent, although, in some cases, it can cause neurological disorders such as epilepsy. In the developing world, it is one of the leading causes of seizures.
2. Echinococcus granulosus (hydatid worm or hyper tapeworm): A tapeworm most commonly found in fresh produce gathered from fields and in the feces of dogs. It causes the growth of cyst-like tapeworm larvae in the body, which may eventually cause pain in the abdomen or chest, nausea and vomiting.
3. Echinococcus multilocularis (a tapeworm): Found in fresh produce and the feces of wild animals. Causes the growth of cyst-like larvae, usually involving the liver. May cause pain in the abdomen, weakness or weight loss.
4. Toxoplasma gondii (single-celled organism): Found in meat, especially pork, lamb and venison, as well as cat feces. Estimated to affect up to 30 percent of the world’s human population, including in the U.S. Most people do not experience any symptoms, although it can cause complications in pregnant women and immunocompromised individuals.
5. Cryptosporidium spp. (single-celled organism): Most commonly found in water or produce contaminated from water. May cause stomach cramping, nausea, vomiting and diarrhea two to 10 days after infection.
6. Entamoeba histolytica (single-celled organism): Most commonly found in water or produce contaminated from water. Not all people will experience symptoms, but the parasite may cause dystentery, bloody diarrhea, weight loss or fatigue.
7. Trichinella spiralis (pork roundworm): Mainly found in pork. Does not cause symptoms in most people, but severe infections may cause nausea, heartburn, dyspepsia and diarrhea two to 7 days after infection.
8. Opisthorchiidae (a family of flatworms): Found in freshwater fish. May cause dyspepsia, abdominal pain, diarrhea or constipation. May cause rarer conditions, such as cholangitis (infection of the bile duct), in more severe cases.
9. Ascaris spp. (roundworms): Found in fresh produce. Causes no symptoms in most people. Mild infections may cause abdominal pain. Severe infections may cause intestinal blockage or impair the growth of children.
10. Trypanosoma cruzi (single-celled organism): Found in fruit juices and bug feces. Causes Chagas disease, which may not show symptoms in most people. In 20-30 percent of cases, however, people develop severe and life-threatening symptoms such as heart rhythm problems or a dilated heart.
The two parasites most commonly found in North America are likely Toxoplasma gondii and Cryptosporidium.
Toxoplasma is considered one of the deadliest foodborne pathogens in the U.S., causing an estimated 750 deaths a year. Cryptosporidium outbreaks and recalls occasionally crop up in the U.S., Canada and Europe.
The report was developed by the Food and Agriculture Organization (FAO) and World Health Organization (WHO), both agencies of the United Nations, based on the request of the Codex Alimentarius Commission. The Codex is now developing new guidelines for controlling foodborne parasites.
Pictured: Trichinella spiralis© Food Safety News