Infectious diseases spread through food or beverages are a common, distressing, and sometimes life-threatening problem for millions of people in the United States and around the world. The U. S. Centers for Disease Control and Prevention (CDC) estimates 76 million people suffer foodborne illnesses each year in the United States, accounting for 325,000 hospitalizations and more than 5,000 deaths.
Foodborne disease is extremely costly. Health experts estimate that the yearly cost of all foodborne diseases in the United States is $5 to $6 billion in direct medical expenses and lost productivity. Infections with the bacteria Salmonella alone account for $1 billion yearly in direct and indirect medical costs.
There are more than 250 known foodborne diseases. Bacteria cause most cases, followed by viruses and parasites. Natural and manufactured chemicals in food products also can make people sick. Some diseases are caused by toxins (poisons) from the disease-causing organism, others by bodily reactions to the organism itself. People infected with food-borne germs may have no symptoms or may develop symptoms ranging from mild intestinal discomfort to severe dehydration and bloody diarrhea.
Recently, public health, agriculture, and environmental officials have expressed growing concern over keeping the nation’s food and water supply safe from terrorist acts.
In this article, five foodborne diseases caused by bacteria will be described: Botulism, Campylobac-teriosis, E. coli infection, Salmonellosis, and Shigellosis.
Vegetarians, especially vegan-vegetarians, may think they are immune to these diseases. It is true that, when we hear about these diseases, the instances are generally related to the handling or eating of meat. But read the facts about each disease carefully. The dangers for meat eaters have not been included in this article to more clearly highlight the susceptibility of vegetarians to these diseases.
Botulism is a rare but serious illness caused by botulinum toxin (poison) produced by Clostridium botulinum bacteria. This toxin affects the nerves and, if untreated, can cause paralysis and respiratory failure. U. S. health care providers report an average of 110 cases of food, infant, and wound botulism to CDC each year. About 10 to 30 outbreaks of foodborne botulism are reported every year. Although this illness does not occur frequently, it can be fatal if not treated quickly and properly.
Often, cases of foodborne botulism come from home-canned foods with low acid content, such as asparagus, green beans, beets, and corn. C. botulinum is anaerobic, which means it can survive and grow with little or no oxygen. Therefore, it can survive very well in sealed containers. Outbreaks of the infection, however, are often from more unusual sources such as chili peppers, tomatoes, and improperly handled baked potatoes wrapped in aluminum foil.
Symptoms and Treatment
Symptoms of foodborne botulism usually begin within 18 to 36 hours after eating contaminated food, but can occur in as few as 6 hours or as much as 10 days afterward. They include double vision and drooping eyelids, slurred speech, dry mouth and difficulty swallowing, and weak muscles.
A health care provider can use laboratory tests to identify C. botulinum toxin in the blood or stool of an infected person. If diagnosed early, health care providers can treat foodborne botulism successfully with an antitoxin that blocks the action of the bacterial toxin circulating in the blood. Although antitoxin keeps the disease from becoming worse, recovery still takes many weeks. Sometimes doctors try to remove contaminated food still in the gut by making the patient vomit or by giving the patient an enema.
Patients who develop severe botulism experience breathing failure and paralysis and need to be put on ventilators (breathing machines). If left untreated, this illness can cause paralysis of the arms, legs, trunk, and muscles that help with breathing. The paralysis usually improves slowly over several weeks.
- botulinum toxin is one of the most potent toxins known in nature. Exposure to the toxin, particularly in an aerosolized form, can be fatal. It has been weaponized by rogue states and is a focus of current counter-bioterrorism efforts.
Steps to prevent foodborne botulism include following strict hygienic steps when home canning; refrigerating oils with garlic or herbs; keeping baked potatoes wrapped in aluminum foil hot until served or refrigerated; and boiling home-canned food before eating it, to kill any bacteria which might lurk in the food.
Campylobacteriosis is an infectious disease caused by Campylo-bacter bacteria. Campylobacter jejuni, C. fetus, and C. coli are the types that usually cause campylobacteriosis in people. C. jejuni causes most cases of the illness.
According to CDC, C. jejuni is the leading cause of bacterial diarrheal illness in the United States, affecting an estimated 2.4 million people every year. The bacteria cause between 5 and 14 percent of all diarrheal illness worldwide. C. jejuni primarily affects children under five years old and young adults (15–29 years old). Health care providers report more than 10,000 cases to CDC yearly. In the United States, few people die from Campylobacter infection.
Drinking non-chlorinated water or handling infected animal or human feces can infect a person. Most frequently, poultry and cattle waste are the sources of the bacteria, but feces from puppies, kittens, and birds also may be contaminated.
Symptoms and Treatment
The symptoms of campylobac-teriosis include diarrhea (often bloody), abdominal cramping and pain, nausea and vomiting, fever, and tiredness.
Some infected people have no symptoms. Campylobacteriosis usually lasts for two to five days, but in some cases as long as ten days. Rarely, some people have convulsions with fever or meningitis.
A health care provider can use laboratory tests to identify Campy-lobacter in the stool of an infected person. Most people infected with Campylobacter will get better with no special treatment. If a person needs treatment, a health care provider can prescribe an antibiotic. Those with diarrhea should drink plenty of water.
Some people infected with Cam-pylobacter develop arthritis. A small number of people with campylo-bacteriosis may develop Guillain-Barré Syndrome (GBS), the leading cause of acute paralysis in the United States. This rare condition develops from two to four weeks after Campylobacter infection and usually after diarrheal symptoms have disappeared. People with GBS suffer from increasing paralysis of the limbs, which lasts for several weeks. In more severe cases, they develop breathing problems requiring very long hospital stays.
Washing hands before preparing food, drinking chlorinated or boiled water, and washing hands after handling pet feces or visiting zoos and petting zoos facilitates prevention of campylobacteriosis.
- coli Infection
Certain types of Escherichia coli bacteria, commonly called E. coli can cause foodborne illness. Harmless strains of E. coli can be found widely in nature, including the intestinal tracts of humans and warm-blooded animals. Disease-causing strains, however, are a frequent cause of both intestinal and urinary-genital tract infections.
Several different strains of harm-ful E. coli can cause diarrheal di-sease. A particularly dangerous type is called enterohemorrhagic E. coli, or EHEC. EHEC often causes bloody diarrhea and can lead to kidney failure in children or people with weakened immune systems.
In 1982, scientists identified the first dangerous strain in the United States. The type of harmful E. coli most commonly found in this country is named O157:H7, which refers to chemical compounds found on the bacterium’s surface. This type produces one or more related, powerful toxins, which can severely damage the lining of the intestines. Other types, including O26:H11 and O111:H8, have also been found in this country and can cause human disease.
Cattle are the main sources of E. coli O157:H7, but other domestic and wild mammals can also harbor these bacteria. E. coli bacteria and its toxins have also been found in alfalfa sprouts, lettuce, unpasteurized apple juice and apple cider, and contaminated well water.
Unsuspecting swimmers have been infected by accidentally swal-lowing unchlorinated or under-chlorinated water in swimming pools contaminated by human feces. Swimming in sewage-contaminated water can also infect people.
Symptoms and Treatment
- coli toxin can damage the lining of the intestine and cause other symptoms including: nausea, severe abdominal cramps, watery or very bloody diarrhea, tiredness, and, occasionally, low-grade fever or vomiting.
Symptoms usually begin from two to five days after eating contaminated food and may last for eight days.
A health care provider can use laboratory tests to identify E. coli in the stool of an infected person. Most people recover from E. coli infection within five to ten days without treatment. Antibiotics are usually not helpful, and health care experts recommend against taking antidiarrheal medicines.
Hemolytic uremic syndrome (HUS), a serious complication of EHEC, can lead to kidney failure. In North America, HUS is the most common cause of acute kidney failure in children, who are particularly prone to this complication. This life-threatening condition is usually treated in an intensive care unit of a hospital, sometimes with blood transfusions and kidney dialysis.
Avoiding unpasteurized juices and washing fresh fruits and vege-tables thoroughly before eating raw or cooking are wise preventative steps.
Enterotoxigenic E. coli (ETEC), which produce a toxin similar to Cholera toxin, can cause diarrhea. These strains typically cause so-called travelers diarrhea because they are prevalent contaminants in food and water in developing countries.
Enteropathogenic E. coli (EPEC) are associated with persistent diarrhea (lasting two weeks or more) and are more common in developing countries where they can be transmitted by contaminated water or contact with infected animals. Health experts do not know how much disease some of these other types of E. coli cause in the United States.
Salmonellosis, or salmonella, is an infection caused by Salmonella bacteria. Salmonella infections are increasing in the United States. Many types of this bacteria cause disease in animals and people. While the occurrence of different types of Salmonella varies from country to country, Salmonella typhimurium and S. enteritidis are the two most commonly found in the United States.
In 1984, an antibiotic-resistant strain of S. typhimurium, called Definitive Type 104 (DT104), was first found in the United Kingdom and recently in the United States. Now it is the second most common strain (after S. enteritidis) of Salmonella found in humans. This strain poses a major new threat because it is resistant to several antibiotics normally used to treat people with Salmonella infections.
Salmonellosis may occur in small, contained outbreaks in the general population or in large outbreaks in hospitals, restaurants, or institutions for children or the elderly. While the disease is found worldwide, health experts most often report cases in North America and Europe. Every year, CDC receives reports of 40,000 cases of salmonellosis in the United States. The agency estimates that 1.4 million people in this country are infected, however, and that 1,000 people die each year with salmonellosis. Symptoms are most severe in the elderly, infants, and people with chronic conditions. People with AIDS are particularly vulnerable to salmonellosis—often suffering from recurring episodes.
Salmonella bacteria can be found sometimes on unwashed fruit. Food prepared on surfaces that previously contained raw meat or meat products can, in turn, become contaminated with the bacteria. This is called cross-contamination.
In the past few years, CDC has received reports of several cases of salmonellosis from eating raw alfalfa sprouts grown in contaminated soil. Salmonella infection frequently occurs after handling pets, particularly reptiles like snakes, turtles, and lizards.
Salmonellosis can become a chronic infection in some people who may not have symptoms. Though they may have no symptoms, they can spread the disease by not washing their hands before preparing food for others. In fact, health care experts recommend that people who know they have salmonellosis not prepare food or pour water for others until a laboratory test shows they no longer carry Salmonella.
Symptoms and Treatment
Symptoms of salmonellosis include diarrhea, fever, abdominal cramps, and headache. In most people, symptoms begin from 12 hours to 3 days after being infected. These symptoms, along with possible nausea, loss of appetite, and vomiting, usually last for four to seven days. Diar-rhea can be severe and require hospi-talization.
A health care provider can use laboratory tests to identify Salmonella in the stool of an infected person.
Most cases of salmonellosis clear up within five to seven days and do not require treat-ment. People with severe diar-rhea may need intravenous fluids. If the infection spreads from the intestines into the bloodstream, health care providers can treat it with antibiotics such as ampicillin.
While most people recover successfully from salmonellosis, a few may develop a chronic condition called Reiter’s syndrome. This syndrome can last for months or years and can lead to arthritis. Its symptoms are painful joints, irritated eyes, and painful urination.
Unless treated properly, Salmonella can escape from the intestine and spread by blood to other organs, sometimes leading to death.
Typhoid fever, a more serious disease, results from infection with S. typhi. This disease, which can be fatal if untreated, is not common in the United States. It is frequently found in developing countries, usually in contaminated water. It is also a risk in areas where flooding or earthquakes cause sewer systems to overflow.
Appropriate antibiotics are usu-ally effective for treating typhoid fever, although the incidence of antibiotic-resistant S. typhi is increasing in some parts of the world.
Wash hands immediately after handling reptiles or coming in contact with pet feces.
Shigellosis, also called bacillary dysentery, is an infectious disease caused by Shigella bacteria. Four main types of Shigella cause infection: Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei. CDC estimates that more than 400,000 cases occur every year in the United States. Health care providers report about 18,000 cases to CDC each year. Most cases in this country are caused by S. sonnei.
People can be infected from foodborne Shigella by eating food or drinking beverages contaminated by food handlers infected with Shigella who did not wash their hands properly after using the bathroom; by eating vegetables grown in fields containing sewage; by eating food contaminated by flies, which were bred in infected feces; and by drinking or swimming in contaminated water.
- sonnei is the most common type of Shigella in developed countries, including the United States. Outbreaks of shigellosis frequently occur in tropical or temperate climates, especially in areas with severe crowding and/or poor hygiene, which sometimes occur in day care and institutional settings.
Some people have no symptoms but can still pass the bacteria to others. An extremely low number of organisms (10-100) is needed to transmit Shigella. Therefore, food service workers who are sick or infected, but have no symptoms, and who do not properly wash their hands after using the toilet commonly transmit it. Those who know they have shigellosis should not prepare food or pour water for others until laboratory tests show they no longer carry Shigella bacteria.
Symptoms and Treatment
As with other foodborne diseases, symptoms of shigellosis are fever, tiredness, watery or bloody diarrhea, nausea and vomiting, and abdominal pain.
Symptoms usually begin within two days after being exposed to Shigella and usually are gone within five to seven days.
People with mild infections usually get better quickly, without taking medicine. When treatment is necessary, health care providers most often prescribe an antibiotic such as ampicillin or ciprofloxacin. Antidiarrheal medicines may make the illness worse.
People who had diarrhea symptoms usually recover completely, although their bowel habits may not return to normal until several months later. S. dysenteriae type 1 produces Shiga toxin and can lead to life-threatening hemolytic uremic syndrome (HUS), the same complication that develops in some cases of infection with E. coli (enterohemor-rhagic E. coli or EHEC).
- flexneri infection can progress to Reiter’s syndrome, which can last for months or years and can lead to chronic arthritis. Its symptoms are painful joints, irritated eyes, and painful urination.
Shigellosis may be prevented by washing hands thoroughly with soap and water before preparing foods and beverages and after using the bathroom or changing infant diapers; by disinfecting the diaper-changing areas after use; and by helping young children wash their hands carefully after they use the bathroom. You should also avoid swallowing swimming pool water.
National Institute of Allergy and Infectious Diseases, National Institutes of Health, U. S. Department of Health and Human Services, Foodborne Diseases, April 2002, www.FoodSafety.gov, (February 19, 2004).