Information from CDC
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 food.
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
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-Barrй 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 recovery.
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