Botulism is caused by toxins produced by the bacterium Clostridium botulinum. It causes paralysis by blocking the release of acetylcholine at nerve endings. There are three main types: foodborne, wound, and infant botulism. Foodborne botulism results from ingesting preformed toxins in improperly canned or cooked foods. Wound botulism occurs when wounds are infected. Infant botulism usually affects children under 1 from ingesting spores. Symptoms include nausea, vomiting, paralysis starting with eyes and face. Treatment focuses on supportive care, antitoxin, and preventing further paralysis. Proper food preservation and handling can prevent botulism.

1. Botulism
Name: Arun Kumar Thakur
Roll No.: 18
Level: M.Sc Microbiology (3rd Sem)
Central Department of Microbiology
Tribhuvan University, Kirtipur
Kathmandu, Nepal

2. Botulism
• Botulism is an acute flaccid paralytic illness caused
by neurotoxins produced by Clostridium botulinum or
rarely neurotoxins of C. butyricum and C.bratii.
• The disease has been linked to foods such as
unrefrigerated home-made salsa, honey, and
traditionally prepared salted or fermented fish.
• The most poisonous substance known.(parental
lethal dose is 10-7 mg/kg)

3. Etiological agent
• C.botulinum is an anaerobic Gram positive, spore forming.
• It is found in soil, marine environment and the intestinal content of
herbivores and fish throughout the world.
• Spores
-ubiquitous
-resistant to heat, light, drying and radiation.
-survive in boiling water for several hours.
• Specific condition for germination are anaerobic ,warmth(10-50°c)
and mild aklalinity.
• There are seven recognized types of the toxin that cause
botulism(A-G), four of which (types A, B, E and, rarely, F) cause
human botulism. Types C, D and E also cause illness in mammals,
birds and fish.

4. Human infection
• Human-to-human transmission of botulism does not occur.
• There are three kinds of botulism, that occur naturally:
• foodborne botulism (due to ingestion of pre-formed
toxins);
• Out break usually occur from canned or uncooked food.
• Home canned food as, asparagus, green beans, beets,
corn, fish and meat.
• Food with low acid (PH >6.0).
• Type A & B produce strong putrefactive odor.
• Type E appeared in native foods.

5. • wound botulism (occurs when wounds are
infected with C. botulinum that secretes the
toxin);
• Rare disease
• Occur with traumatic injuries.
• Occurs even if no skin breakdown (crush
injuries).
• In the last years from injection
abusers(heroin).

6. • Infant botulism (typically in children less than
1 year old, after eating bacterial spores from
food that develop into toxins in the
intestines).
• Ingestion of contaminated honey.
• Slow intestinal transit (<1 stool/day).
• Sources of spores, home dust, vaccum cleaner
dust, contaminated honey or may be corn
syrup.

7. Pathogenesis
• Toxin enters bloodstream from mucosal surface or
wound.
• Binds to perpherial cholineric nerve ending.
• Inhibits release of acetylcholine, preventing muscle
from contracting.
• Symmetrical, descending paralysis occurs beginning
with cranial nerves and progessing downward.
• Can result from airway obstruction or paralysis of
respiratory muscles.
• Secondary complications related to prolonged
ventilatory support and intensive care.

8. Clinical signs and symptoms
• Incubation period: 4 hours–4 days.
• The symptoms described below are not caused
by the organism itself, but by the toxin that the
bacterium releases.
• Nausea, vomiting, sometimes constipation,
followed by toxic effects on the central nervous
system (drooping eyelids, blurred or double
vision, dizziness, difficulty in swallowing, blurred
speech, muscle weakness, respiratory paralysis

9. Laboratory diagnosis
• A diagnosis of botulism must be considered in
patient with symmetric descending paralysis who
are afebrile and mentally intact (Since it is a
bioterrorism agent, used BSL-3)
• Toxin in serum, stool, gastric aspirate, suspected
food.
• Culture of stool or gastric aspirate (takes 5-7
days).
• Electromycography
• Mouse neutralization test( result in 24 hours).

10. Culture
• Anaerobic Culture Media-Robertson’s Cooked
Meat Medium

11. Continued..
• Botulinum toxin can be detected by a variety
of techniques, including:
• ELISA TEST
• Electrochemiluminescent (ECL) test.

12. Treatment
• Generally, supportive care is the mainstay for
treatment of botulism.
• Prolonged intensive care, mechanical ventilation,
and intravenous feeding may be required.
• Antitoxin administration is indicated as soon as
possible after a clinical diagnosis has been made.
This does not reverse the effects of the disease,
but can prevent further paralysis.
• Antibiotics are not effective against toxins, but
are needed to treat secondary bacterial
infections.

13. Prevention and control
Individuals
• When preserving food at home, use a pressure canner and
rigorously follow guides for home canning.
• While preparing food, follow the WHO Five Keys to Safer
Food: keep clean; separate raw and cooked food; cook
thoroughly; keep food at safe temperatures; use safe water
and raw materials.
• Take good care to avoid contamination of food by soil or
other sources likely to harbour these bacteria.
Community
• The community should be educated regarding proper
preservation of home-made food, especially canning, to
destroy spores.

14. Thank you