Frequently Asked Questions
Botulism is a rare but serious paralytic illness caused by a nerve
toxin that is produced by the bacterium Clostridium botulinum.
There are three main kinds of botulism. Foodborne botulism is
caused by eating foods that contain the botulism toxin. Wound
botulism is caused by toxin produced from a wound infected with
Clostridium botulinum. Infant botulism is caused by consuming
the spores of the botulinum bacteria, which then grow in the intestines
and release toxin. All forms of botulism can be fatal and are
considered medical emergencies. Foodborne botulism can be especially
dangerous because many people can be poisoned by eating a contaminated
kind of germ is Clostridium botulinum?
Clostridium botulinum is the name of a group of bacteria
commonly found in soil. These rod-shaped organisms grow best in
low oxygen conditions. The bacteria form spores which allow them
to survive in a dormant state until exposed to conditions that
can support their growth. There are seven types of botulism toxin
designated by the letters A through G; only types A, B, E and
F cause illness in humans.
common is botulism?
In the United States an average of 110 cases of botulism are reported
each year. Of these, approximately 25% are foodborne, 72% are
infant botulism, and the rest are wound botulism. Outbreaks of
foodborne botulism involving two or more persons occur most years
and usually caused by eating contaminated home-canned foods. The
number of cases of foodborne and infant botulism has changed little
in recent years, but wound botulism has increased because of the
use of black-tar heroin, especially in California.
are the symptoms of botulism?
The classic symptoms of botulism include double vision, blurred
vision, drooping eyelids, slurred speech, difficulty swallowing,
dry mouth, and muscle weakness. Infants with botulism appear lethargic,
feed poorly, are constipated, and have a weak cry and poor muscle
tone. These are all symptoms of the muscle paralysis caused by
the bacterial toxin. If untreated, these symptoms may progress
to cause paralysis of the arms, legs, trunk and respiratory muscles.
In foodborne botulism, symptoms generally begin 18 to 36 hours
after eating a contaminated food, but they can occur as early
as 6 hours or as late as 10 days.
is botulism diagnosed?
Physicians may consider the diagnosis if the patient's history
and physical examination suggest botulism. However, these clues
are usually not enough to allow a diagnosis of botulism. Other
diseases such as Guillain-Barr� syndrome, stroke, and myasthenia
gravis can appear similar to botulism, and special tests may be
needed to exclude these other conditions. These tests may include
a brain scan, spinal fluid examination, nerve conduction test
(electromyography, or EMG), and a tensilon test for myasthenia
gravis. The most direct way to confirm the diagnosis is to demonstrate
the botulinum toxin in the patient's serum or stool by injecting
serum or stool into mice and looking for signs of botulism. The
bacteria can also be isolated from the stool of persons with foodborne
and infant botulism. These tests can be performed at some state
health department laboratories and at CDC.
can botulism be treated?
The respiratory failure and paralysis that occur with severe botulism
may require a patient to be on a breathing machine (ventilator)
for weeks, plus intensive medical and nursing care. After several
weeks, the paralysis slowly improves. If diagnosed early, foodborne
and wound botulism can be treated with an antitoxin which blocks
the action of toxin circulating in the blood. This can prevent
patients from worsening, but recovery still takes many weeks.
Physicians may try to remove contaminated food still in the gut
by inducing vomiting or by using enemas. Wounds should be treated,
usually surgically, to remove the source of the toxin-producing
bacteria. Good supportive care in a hospital is the mainstay of
therapy for all forms of botulism. Currently, antitoxin is not
routinely given for treatment of infant botulism.
there complications from botulism?
Botulism can result in death due to respiratory failure. However,
in the past 50 years the proportion of patients with botulism
who die has fallen from about 50% to 8%. A patient with severe
botulism may require a breathing machine as well as intensive
medical and nursing care for several months. Patients who survive
an episode of botulism poisoning may have fatigue and shortness
of breath for years and long-term therapy may be needed to aid
can botulism be prevented?
Botulism can be prevented. Foodborne botulism has often been from
home-canned foods with low acid content, such as asparagus, green
beans, beets and corn. However, outbreaks of botulism from more
unusual sources such as chopped garlic in oil, chile peppers,
tomatoes, improperly handled baked potatoes wrapped in aluminum
foil, and home-canned or fermented fish. Persons who do home canning
should follow strict hygienic procedures to reduce contamination
of foods. Oils infused with garlic or herbs should be refrigerated.
Potatoes which have been baked while wrapped in aluminum foil
should be kept hot until served or refrigerated. Because the botulism
toxin is destroyed by high temperatures, persons who eat home-canned
foods should consider boiling the food for 10 minutes before eating
it to ensure safety. Instructions on safe home canning can be
obtained from county extension services or from the US Department
of Agriculture. Because honey can contain spores of Clostridium
botulinum and this has been a source of infection for infants,
children less than 12 months old should not be fed honey. Honey
is safe for persons 1 year of age and older. Wound botulism can
be prevented by promptly seeking medical care for infected wounds
and by not using injectable street drugs.
are public health agencies doing to prevent or control botulism?
Public education about botulism prevention is an ongoing activity.
Information about safe canning is widely available for consumers.
State health departments and CDC have persons knowledgeable about
botulism available to consult with physicians 24 hours a day.
If antitoxin is needed to treat a patient, it can be quickly delivered
to a physician anywhere in the country. Suspected outbreaks of
botulism are quickly investigated, and if they involve a commercial
product, the appropriate control measures are coordinated among
public health and regulatory agencies. Physicians should report
suspected cases of botulism to a state health department.
For information and quidelines on canning foods at home:
Home Canning Guide