Three major foodborne illnesses account for nearly two-thirds of all infections Norovirus, Campylobacter and Salmonella.
Norovirus illness usually develops 24 to 48 hours after ingestion of contaminated food or water. Symptoms typically last a relatively short amount of time, approximately 24 to 48 hours. These symptoms include nausea, vomiting, diarrhea, and abdominal pain. Headache and low-grade fever may also accompany this illness. People infected with norovirus usually recover in two to three days without serious or long-term health effects.
Campylobacter infections do not cause all infected person to fall ill or develop symptoms. However, when a person is infected and develops symptoms, the illness is called campylobacteriosis.
The amount of time from infection to the onset of symptoms—typically referred to as the incubation period—can vary to a significant degree. The incubation period varies from 1 to 7 days, a characteristic that is probably inversely related to the dose ingested.
Although most cases of campylobacteriosis are self-limiting, up to 20% have a prolonged illness (longer than 1 week) or a relapse, and 2% to 10% may be followed by chronic sequelae. Other typical symptoms of C. jejuni infection include fever, nausea, vomiting, abdominal pain, headache, and muscle pain. The illness usually lasts no more than one week; however, severe cases may persist for up to three weeks, and roughly 25% of individuals experience symptom relapse. In most cases, the worst of the illness, which is to say the most intense and painful of the symptoms, lasts 24-48 hours, before then taking a week to fully resolve.
For those persons who suffer a Campylobacter infection that does not resolve on its own, the complications (or sequelae) can be many. The complications can include septicemia (bacterial pathogens in the blood, also known as bacteremia), meningitis, inflammation of the gall bladder (cholecystitis), urinary tract infections, appendicitis, and Guillain-Barré Syndrome (GBS).
An estimated one case of GBS occurs for every 1,000 Campylobacter infections. Up to 40% of GBS patients have evidence of recent Campylobacter infection. GBS occurs when an infected person’s immune system makes antibodies against components of Campylobacter, and these antibodies attack components of the body’s nerve cells because they are chemically like bacterial components.
Salmonella infections can have a broad range of illness, from no symptoms to severe illness. The most common clinical presentation is acute gastroenteritis. Symptoms include diarrhea, and abdominal cramps, often accompanied by fever of 100°F to 102°F (38°C to 39°C). Other symptoms may include bloody diarrhea, vomiting, headache and body aches. The incubation period, or the time from ingestion of the bacteria until the symptoms start, is generally 6 to 72 hours. People with salmonellosis usually recover without treatment within 3 to 7 days. Nonetheless, the bacteria will continue to be present in the intestinal tract and stool for weeks after recovery of symptoms—on average, 1 month in adults and longer in children.
In approximately 5% of non-typhoidal infections, patients develop bacteremia. In a small proportion of those cases, the bacteria can cause a focal infection, where it becomes localized in a tissue and causes an abscess, arthritis, endocarditis, or other severe illness. Infants, the elderly, and immune-compromised persons are at greater risk for bacteremia or invasive disease.
Overall, approximately 20% of cases each year require hospitalization, 5% of cases have an invasive infection, and one-half of 1% die. Infections in infants and in people 65 years of age or older are much more likely to require hospitalization or result in death.  There is some evidence that Salmonella infections increase the risk of developing digestive disorders, including irritable bowel syndrome.
Although most persons that become ill with diarrhea caused by Salmonella recover without any further problems, a small number of persons develop a complication often referred to as reactive arthritis. Symptoms of reactive arthritis include inflammation (swelling, redness, heat, and pain) of the joints, the genitourinary tract (reproductive and urinary organs), or the eyes.
More specifically, symptoms of reactive arthritis include pain and swelling in the knees, ankles, feet, and heels. It may also affect wrists, fingers, other joints, or the lower back. Tendonitis (inflammation of the tendons) or enthesitis (inflammation where tendons attach to the bone) can occur. Other symptoms may include prostatitis, cervicitis, urethritis (inflammation of the prostate gland, cervix, or urethra), conjunctivitis (inflammation of the membrane lining the eyelid) or uveitis (inflammation of the inner eye). Ulcers and skin rashes are less common. Symptoms can range from mild to severe.
The Food Safety Attorneys at Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of food poisoning outbreaks.