Botulism Symptoms

It is critical to be able to recognize the signs and symptoms of botulism because if it is not treated in time, the toxin can prove fatal. The botulinum toxin's lethal dose to humans is 1 mcg (micrograms). Put on a different scale, an aerosolized botulism toxin (if intentionally dispersed as a terrorism act) could potentially kill 1.5 million people.

About 90% of botulinum infected people will present at least three of the following symptoms:

• nausea, vomiting, abdominal cramps
• difficulty swallowing
• double vision
• dilated/fixed pupils
• dry mouth

Some of these symptoms can appear as early as six-hours from toxin ingestion but may not be initially linked to botulism (due to its vagueness). Gastrointestinal symptoms tend to be signs of a food-borne infection. Double vision and dilated pupils are some of the first signs of a neurological damage and usually appear within this same time frame. 

An alliteration tool may help people recognize the onset of botulism and the typical progression, in order of appearance:

"The Dozen D's"

• double vision (diplopia) 
• dilated pupils 
• droopy eyes
• droopy face
• diminished gag reflex
• dysphagia (difficulty swallowing)
• dysarthria (difficulty pronouncing words)
• dysphonia (difficulty speaking)
• difficulty lifting head
• descending paralysis
• diaphragmatic paralysis

Half of all diagnosed patients will experience double vision but are otherwise mentally intact. More serious conditions that accompany botulism, such as airway obstruction, lead to delirium and need for critical care.

Sources:
http://emedicine.medscape.com/article/213311-clinical#a0217
http://emedicine.medscape.com/article/829125-clinical#a0217
http://www.mayoclinic.com/health/botulism/DS00657/DSECTION=symptoms
http://www.cdc.gov/nczved/divisions/dfbmd/diseases/botulism/#symptoms

How did clostridium botulinum get in my food?

Botulism is thankfully a rare disease because it cannot be transmitted from person-to-person and also because most people properly prepare their food. However, clostridium botulinum still persists in nature (soil) which means it is important to be aware. Botulism is caused by neurotoxins that the bacterium clostridium botulinum produces. Even a micro-liter could be lethal.

These gram positive, rod-shaped microorganisms are obligate anaerobes, so they thrive in the airtight atmosphere that home-canning of fish/vegetables provide. It is in this environment that the spores are able to release the toxins. Consumers should pressure cook food items before canning because high temperatures are not enough to denature the spores. 

Once ingested, it would take 8 to 36 hours for symptoms to show. Symptoms include: difficulty breathing and swallowing, nausea, and weakness with paralysis. The c. botulinum toxin essentially blocks the activity of acetylcholine--a neurotransmitter responsible for muscle activation--which is how botulism leads to paralysis and respiration difficulties.

The above diagram illustrates how the botulinum toxin (heavy chain) binds to the neuronal membrane of the neuromuscular junction. The light chain of the toxin cleaves proteins of the synaptic fusion complex. With the toxin introduced, the complex is not longer able to allow the synaptic vesicles (which release acetylcholine) to fuse with the membrane and the muscles are now paralyzed. 

Sources:
http://en.wikipedia.org/wiki/Botulism

http://en.wikipedia.org/wiki/Botulinum_toxin
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001624/
http://www.cidrap.umn.edu/cidrap/content/bt/botulism/biofacts/botulismfactsheet.html#_Therapy_for_Botulism

Botulism Statistics

Food-borne botulism is relatively rare in the United States but what is the meaning of those statistics when you are one of the people who are infected with clostridium botulism? Here are Center of Disease Control's latest statistics:

11 cases in United States
[2009]
Median age: 56 years (range: 7–91 years)

Death: 1 confirmed, 0 without information

Gender: 6 (55%) male, 5 (45%) female

Toxin type:  10 (91%) type A, 1 (9%) type B

3 outbreaks (defined as two or more cases resulting from a common exposure)

What we can take from the information presented is that food-borne illnesses such as botulism do not discriminate against gender or age. It seems that food-borne botulism cases are clustered in western states California and Washington which is attributed to the home-canning traditions of vegetables and fish.


Sources:


"National Botulism Surveillance." Centers for Disease Control and Prevention. <http://www.cdc.gov/nationalsurveillance/botulism_surveillance.html> Oct 18 2011.

Botulism

The first time I ever heard about botulism, or the bacterium clostridium botulinum that causes it, was when I was watching a news story on a woman who became paralyzed after eating infected hamburger meat. She was a dancer. If I remember correctly, there was a huge ordeal about ground beef factories not being held accountable for tainted meat...especially since the origins of the various meat parts were/are not documented. The woman--whom I should do research on--tried to get the FDA to hone in on the issue.

The second time I heard about it was through the cosmetic treatment using clostridium botulinum to treat wrinkles or to block certain nerves. I would like to learn more about this food-borne pathogen because of the extreme damage it can do and what public health can do to keep the number of cases as low as they are today.