6. Illnesses and symptoms
Bacillus cereus
A type of bacteria that grow in food and produces toxins. These toxins can cause two types of illness - one that is characterized by watery diarrhoea and cramp, the other, called emetic toxin, by nausea and vomiting. The incubation period for diarrhoeal poisoning is 6 to 15 hours, and for the emetic toxin 30 minutes - 6 hours. The illness is generally over in 24 hours.
Campylobacter
Can be food or water borne. The incubation period is from 1 to 11 days, usually 2 to 5 days. The symptoms include severe abdominal pain, diarrhoea, fever, nausea and occasionally vomiting. These symptoms can last for up to 2 weeks.
Clostridium perfringens
Found in beef, poultry and gravies. The incubation period is 6 to 24 hours, and the symptoms are diarrhoea and abdominal cramp, without fever or vomiting. It usually only lasts 24 hours, but in severe cases may last 1 to 2 weeks.
Cryptosporidiosis
Can be food or water borne. The incubation period is from one to 28 days, usually 7 to 10 days. The symptoms include profuse watery diarrhoea, abdominal pain, vomiting, fever and weight loss. These symptoms can last for up to 4 weeks.
E. coli 0157
Can be food or water borne. The incubation period is from 4 to 14 days, usually 3 to 4 days. The symptoms range from mild diarrhoea to severe bloody diarrhoea with abdominal pain and can last for up to 2 weeks. In some extreme cases serious problems can occur including kidney failure. It is important to get medical advice quickly if you suffer from bloody diarrhoea.
Giardiasis
Can be food or water borne. The incubation period is from 1 to 21 days, usually 7 to 10 days. The symptoms include watery diarrhoea, abdominal pain, wind, vomiting, fever, weight loss and constipation. These symptoms can last for several weeks.
Hepatitis A
Can be food or water borne. The incubation period is 15 to 50 days, usually about 25 days. Epidemics occur particularly in developing countries. The symptoms include fever, headache and nausea, followed by vomiting, diarrhoea and jaundice. These symptoms can last for 3 weeks.
Listeria monocytogenes
Food borne infection. The incubation period is from 3 to 70 days. The symptoms include fever, stiff neck, confusion, weakness, vomiting, sometimes preceded by diarrhoea. It can be a serious infection for pregnant women, the elderly and people with reduced immune function. If you are very ill with fever or stiff neck, consult your doctor immediately. Antibiotics given promptly can cure the infection and, in pregnant women, can prevent infection of the foetus.
Norovirus or viral gastrointestinal infections
Strictly speaking, not food poisoning. The incubation period is usually 24 to 48 hours. These are usually quite severe bouts of fever, nausea, vomiting (that may be projectile) and explosive watery diarrhoea. Recovery is normally within 48 hours, after which a person may still be a little weak for a day or so.
Salmonella
Food borne illness. The incubation period is 12 to 72 hours. The symptoms include diarrhoea, vomiting, abdominal pain and fever. These symptoms can last for up to 7 days.
Scombroid poisoning
Food borne illness. Poorly stored oily fish can generate high levels of histamine, which can cause allergic reactions. Symptoms can include facial flushing, sweating, upper body rashes, tingling mouth, palpitations, severe headache, abdominal cramps, vomiting and diarrhoea. It usually occurs shortly after eating the food. People with severe symptoms should receive medical assistance.
Staphylococcus Aureus
Can be a food borne illness. The incubation period is 1 to 6 hours. The symptoms include nausea, vomiting, diarrhoea, loss of appetite, severe abdominal cramps and mild fever, and can last for 24 to 48 hours.
Shigellosis
Infectious illness which can be passed from food or an infected person. The incubation period is 1 to 7 days, usually 1 to 3 days. The symptoms include severe diarrhoea (often with blood or mucous), vomiting, abdominal pain and fever. These symptoms can last from several days to several weeks, but usually 4 to 7 days.
Vibrio
Typically causes illness in people who eat raw or lightly cooked contaminated seafood, particularly oysters. The most common is V. parahaemolyticus. The incubation period is 2 to 48 hours. The symptoms include explosive watery diarrhoea, nausea, vomiting, abdominal cramps and sometimes fever. It is typically over in 2 to 8 days.