Foodborne and Waterborne Illness: Types of Infections

• Salmonella. This widespread infection has two main types: typhoid fever and non-typhoid infection. Salmonella usually occurs due to undercooked poultry, contamination of foods or cooking surfaces, and raw or undercooked eggs (including egg-containing products, such as mayonnaise and custards). Milk, meat, and produce, such as alfalfa sprouts, may also transmit disease.
  
  Typhoid fever often results in fever, abdominal pain, swollen liver and spleen, diarrhea (which may be bloody), and skin rash. Non-typhoid salmonella infection often results in nausea, vomiting, diarrhea, and fever, and is the most common cause of foodborne illness in the United States.
• Campylobacter. The second most common cause of foodborne illness in the United States is campylobacter. Like salmonella, it is a common resident of the chicken's intestinal tract and can contaminate chicken meat during processing. Undercooked poultry and contamination of other foods are the most likely sources. As much as 60 percent of retail poultry products throughout the world and up to 85 percent in the United States are contaminated with campylobacter. Bloody diarrhea may occur.
• Shigella. The third most common cause of foodborne illness in the United States is shigella. It causes bloody diarrhea and may result in severe blood disorders. It spreads through food, water, or person-to-person contact, and is common in nursing homes and daycare settings.
• Cryptosporidium. This parasite is transmitted through ingestion of its eggs in contaminated water, or exposure to cows and their manure. It can also contaminate produce and unpasteurized milk. Cryptosporidium can also be found in pools and spas and can spread from person to person.
• Escherichia coli. The E. coli O157:H7 strain is spread most often through undercooked hamburger. Unpasteurized juice and raw produce contaminated by cattle manure may also be sources. It may cause bloody diarrhea and can lead to severe blood disorders. Like salmonella, it usually occurs in the summer and fall.
• Yersinia. This bacterial infection typically comes from undercooked pork, unpasteurized milk, or contaminated water.
• Vibrio cholerae. This bacterial infection results in a severe diarrhea. It occasionally occurs along the Gulf Coast from contaminated water. Another type of vibrio infection, Vibrio parahaemolyticus, is due to ingestion of contaminated shellfish.
• Cyclospora. This infection occurs due to produce that has been exposed to contaminated water and from person-to-person contact. It may cause diarrhea and other symptoms, such as fatigue.
• Bacillus cereus. This infection can occur in under-heated foods, such as rice, and is often found in food left under heating lamps. It can cause severe vomiting and diarrhea.
• Staphylococcus aureus. Common sources include contaminated salads, eggs, meat, and dairy products that have been prepared and left at room temperature.
• Viral infections. Norovirus is the most common viral cause of diarrhea. It occurs in families and among persons living in other close quarters, such as cruise ships, and can be transmitted through the air by contaminated hands and other objects.
• Entamoeba histolytica. Infection is most common in tropical regions. In addition to causing painful, severe diarrhea with blood and mucus, the infection may also cause liver abscess and ulcers on the anus. It can be transmitted sexually, as well as by consumption of contaminated water.
• Listeria monocytogenes. Listeria is fatal in nearly 20 percent of cases. It can cause meningitis and is most common in infants and elderly persons. This organism is the basis for the warning to pregnant women not to consume unpasteurized soft cheeses, particularly from Latin America. Raw hot dogs and deli meats are also high-risk foods.
• Clostridium botulinum. This bacterium causes a life-threatening paralysis called botulism. Infection can occur as a result of home canning, fish fermentation, and extended use of food warmers.
• Toxoplasma. This infection may occur through ingestion of raw beef or lamb or by contamination from cat feces (e.g., in infrequently cleaned litter boxes and gardens). Infection with toxoplasmosis during pregnancy is dangerous to the fetus.
• Trichinosis. This disease is caused by ingestion of undercooked pork and wild game, such as bear. Cattle and horse meat can also be contaminated. Trichinosis rarely causes diarrhea, but may cause eye, heart, or brain symptoms. It is now rare in the United States, due to regulatory controls on the feeding of pigs.
• Brucellosis. Brucellosis is found in contaminated dairy and meat products, commonly from Latin America. Brucellosis may result in high fevers, meningitis, bone infection, and rashes.
• Tapeworms. Tapeworms can result from eating raw fish, beef, and pork. One type of tapeworm can travel to the brain and may result in seizures.
• Prions. Prions are abnormal proteins that cause brain disease, such as bovine spongiform encephalopathy ("mad cow disease"). The risk to humans has been reduced by regulations for livestock feeding and processing.