Escherichia coli O157:H7 is a zoonotic pathogen that is an important cause of human foodborne and waterborne disease, with a spectrum of illnesses ranging from asymptomatic carriage and diarrhea to the sometimes fatal hemolytic uremic syndrome. Outbreaks of E. coli O157:H7 disease are often associated with undercooked beef, but there are other sources of transmission, including water, produce, and animal contact, which can often be linked directly or indirectly to cattle. Thus, preharvest control of this pathogen in cattle production should have a large impact on reducing the risk of human foodborne illness. In this review, we will summarize preharvest research on E. coli O157:H7 in cattle and the production environment, focusing on factors that may influence the transmission, prevalence, and levels of this pathogen, such as season, diet, high-level shedders, and animal stress. In addition, we will discuss recent research on the reduction of this pathogen in cattle production, including vaccination, probiotics, bacteriophage, and manure treatments
Overview
Escherichia coli (E. coli) bacteria normally live in the
intestines of healthy people and animals. Most varieties of E. coli are
harmless or cause relatively brief diarrhea. But a few particularly nasty
strains, such as E. coli O157:H7, can cause severe abdominal cramps, bloody
diarrhea and vomiting.
You may be exposed to E. coli from contaminated water or food —
especially raw vegetables and undercooked ground beef. Healthy adults usually
recover from infection with E. coli O157:H7 within a week, but young children
and older adults have a greater risk of developing a life-threatening form of
kidney failure called hemolytic uremic syndrome.
Symptoms
Signs and symptoms of E. coli O157:H7 infection typically begin
three or four days after exposure to the bacteria, though you may become ill as
soon as one day after to more than a week later. Signs and symptoms include:
Diarrhea, which may range from mild and watery to severe and
bloody
Abdominal cramping, pain or tenderness
Nausea and vomiting, in some people
Diagnosis
To diagnose illness caused by E. coli infection, your doctor
will send a sample of your stool to a laboratory to test for the presence of E.
coli bacteria. The bacteria may be cultured to confirm the diagnosis and
identify specific toxins, such as those produced by E. coli O157:H7.
Treatment
For illness caused by
E. coli, no current treatments can cure the infection, relieve symptoms or
prevent complications. For most people, treatment includes:
Rest
Fluids to help
prevent dehydration and fatigue
Avoid taking an anti-diarrheal
medication — this slows your digestive system down, preventing your body from
getting rid of the toxins. Antibiotics generally aren't recommended because
they can increase the risk of serious complications.
If you have a serious
E. coli infection that has caused hemolytic uremic syndrome, you'll be
hospitalized and given supportive care, including IV fluids, blood transfusions
and kidney dialysis.
Clear liquids. Drink plenty of
clear liquids, including water, clear sodas and broths, gelatin, and juices.
Avoid apple and pear juices, caffeine, and alcohol.
Add foods gradually.
When you start feeling better, stick to low-fiber foods at first. Try soda
crackers, toast, eggs or rice.
Avoid certain foods. Dairy products, fatty foods, high-fiber foods or
highly seasoned foods can make symptoms worse
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