John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Symptoms of food poisoning depend on the type of contaminant and the amount eaten. The symptoms can develop rapidly, within 30 minutes, or slowly, worsening over days to weeks. Most of the common contaminants cause:
Usually food poisoning is not serious, and the illness runs its course in 24-48 hours.
Viruses account for most food poisoning cases where a specific contaminant is found.
Noroviruses are a group of viruses that cause a mild illness (often termed "stomach flu") with nausea, vomiting, diarrhea,
headache, and low-grade fever. These symptoms usually resolve in two to three days. It is the most common viral cause of adult food poisoning and is transmitted from water,
shellfish, and vegetables contaminated by feces, as well as from person to person. Outbreaks are more common in densely populated areas such as nursing homes, schools, and cruise ships (hence the
viral infection is also known as the "Cruise Ship Illness"). The term
Norovirus has been approved as the official name for this group of viruses. Several other names have been used for noroviruses, including Norwalk-like viruses, caliciviruses (because they belong to the virus family
Caliciviridae), and small round structured viruses.
Rotavirus: Causes moderate to severe illness with vomiting followed by watery diarrhea and fever. It is the most common cause of food poisoning in infants and children and is transmitted from person to person by fecal contamination of food and shared play areas.
Hepatitis A: Causes
moderate illness with sudden onset of fever, loss of appetite, abdominal
pain, and feeling of tiredness followed by
jaundice, which is a yellowing of the eyes and skin.
Symptoms usually last less than two months, but can be prolonged or
relapse for up to six months. It is transmitted from person to person by fecal contamination of food.
Bacteria can cause food poisoning in two different ways. Some bacteria infect the intestines, causing
inflammation and difficulty absorbing nutrients and water, leading to diarrhea. Other bacteria produce chemicals in foods (known as toxins) that are poisonous to the human
digestive system. When eaten, these chemicals can lead to nausea and vomiting,
kidney failure, and even death.
Salmonellae: Salmonellae are bacteria that may cause food poisoning; the illness itself is often referred to as
Salmonella or Salmonella infection.
TheCDCestimates that each year 1 million people are infected
with Salmonella, amounting to $365 million in direct medical costs annually.
Salmonellae cause a moderate illness with nausea, vomiting, crampy diarrhea, and
headache, which may come back a few weeks later as
arthritis (joint pains). In people with impaired immune systems (such as people with kidney disease,
HIV/AIDS, or those receiving
cancer), Salmonellae can cause a life-threatening illness. The illness is transmitted by undercooked foods such as eggs, poultry, dairy products, and seafood.
Campylobacter: Causes mild illness with fever, watery diarrhea, headache, and muscle aches. Campylobacter is the most commonly identified food-borne bacterial infection encountered in the world. It is transmitted by raw poultry, raw milk, and water contaminated by animal feces.
Staphylococcus aureus: Causes moderate to severe illness with rapid onset of nausea, severe vomiting,
dizziness, and abdominal cramping. These bacteria produce a
toxin in foods such as cream-filled cakes and pies, salads (most at risk are potato, macaroni, egg, and tuna salads, for example) and dairy products. Contaminated salads at picnics
are common if the food is not chilled properly.
Bacillus cereus: Causes mild illness with rapid onset of vomiting, with or without diarrhea and abdominal cramping. It is associated with rice (mainly fried rice) and other starchy foods such as pasta or potatoes.
It has been speculated that this bacteria may also be used as a potential terrorist weapon.
Escherichia coli (E coli): Causes moderate to severe illness that begins as large amounts of watery diarrhea,
which then turns into bloody diarrhea. There are many different types of this bacteria. The worst strain can cause kidney failure and death (about 3%
to 5% of all cases). It is transmitted by eating raw or undercooked hamburger, unpasteurized milk or juices, or contaminated well water. Outbreaks of food poisoning due to
E. coli have also occurred following ingestion of contaminated produce.
Shigella (traveler's diarrhea): Causes moderate to severe illness with fever,
diarrhea containing blood or mucus or both, and the constant urge to have bowel movements. It is transmitted in water polluted with human wastes.
Listeria monocytogenes: Listeriosis is a moderate to
severe illness with nausea and vomiting. Some affected individuals can
progress to develop
meningitis from Listeria. It is transmitted on many tips of uncooked
foods such as meats, fruits, vegetables, soft cheeses, unpasteurized milk, and cold
cut meats. Pregnant woman and newborns are at increased risk for serious
infections. In 2011, in an outbreak caused by tainted cantaloupe, 25 people
died and 123 people were infected in 26 states.
Clostridium botulinum (botulism): Causes severe illness affecting the nervous system. Symptoms start as
blurred vision. The person then
develops problems talking and overall weakness. Symptoms then progress to breathing difficulty and
the inability to move arms or legs. Infants and young children are particularly at risk. It is transmitted in foods such as home-packed canned goods, honey, sausages, and seafood.
Because botulism can be released in the air, it is considered a potential
biological weapon for terrorists.
Vibrio cholerae: Causes mild to moderate illness with crampy diarrhea, headache, nausea, vomiting, and fever with chills. It strikes mostly in the warmer months of the year and is transmitted by infected, undercooked, or raw seafood.
Vibrio parahaemolyticus: Causes moderate to severe abdominal
cramping, nausea, vomiting, and fever. In immunocompromised individuals, it
can cause severe or deadly disease. It is transmitted by eating raw or
undercooked fish, particularly oysters.
Parasites rarely cause food poisoning. When they do, they are usually swallowed in contaminated or untreated water and cause long-lasting but mild symptoms.
Giardia (beaver fever): Causes mild illness with watery diarrhea often lasting
one to two weeks. It is transmitted by drinking contaminated water, often from lakes or streams in cooler mountainous climates.
The infection can also be spread from person to person by food or other
items contaminated with feces from an infected person.
Cryptosporidium: Causes moderate illness with large amounts of watery diarrhea lasting
two to four days. May become a long-lasting problem in people with poor immune systems (such as people with kidney disease or HIV/AIDS or those on chemotherapy for cancer). It is transmitted by contaminated drinking water.
Toxoplasma: The CDC estimates that more than 60 million people in the U.S. carry the
Toxoplasma parasite, but few have symptoms because the immune system keeps the parasite from causing illness. When it does cause disease, symptoms include headache, blurred vision, and
eye pain. It is transmitted by eating undercooked or raw meat, contaminated water, or contact with contaminated cat feces.
Pregnant women and those with compromised immune systems infected with
Toxoplasma can have severe health complications.
Toxic agents are the least common cause of food poisoning. Illness is often an isolated episode caused by poor food preparation or selection (such as picking wild mushrooms).
Mushroom toxins: Illness can range from mild to deadly depending on the type of mushroom eaten. Often there is nausea, vomiting, and diarrhea. Some types of mushrooms produce a nerve toxin, which causes
sweating, shaking, hallucinations, and
Ciguatera poisoning: Caused by eating fish that contains toxins produced by a marine algae called
Gambierdiscus toxicus. It can cause moderate to severe illness with numbness of the area around the mouth and lips that can spread to the arms and legs, nausea, vomiting, muscle pain and weakness, headache,
dizziness, and rapid heartbeat. The toxin may cause sensory problems in which hot things feel cold and cold things feel hot. It is transmitted by eating certain large game fish from tropical waters-most specifically barracuda, grouper, snapper, and jacks. According to the CDC, ciguatera has no cure. Symptoms may disappear in days or weeks, but may persist for years.
Scombroid: Causes mild to moderate illness with facial flushing, burning around the mouth and lips,
peppery-taste sensations, a red rash on the upper body, dizziness, headache, and itchy skin.
Severe symptoms may include blurry vision, respiratory distress, and swelling of the tongue and mouth. Symptoms typically last from four to six hours, and rarely
more than one or two days. It is transmitted in seafood, mostly mahi-mahi and tuna, but can also be in Swiss cheese.
Pesticides: Cause mild to severe illness with weakness, blurred vision, headache, cramps, diarrhea, increased production of saliva, and shaking of the arms and legs. Toxins are transmitted by eating unwashed fruits or vegetables contaminated with pesticides.