Botulism

In all forms of botulism, the signs and symptoms are similar. However, in the food borne variety, gastrointestinal symptoms like vomiting and diarrhea may be present.

The most common presentation is the characteristic weakness of the muscles supplied by cranial nerves. Muscle paralysis starts from the face which manifests as loss of facial expressions, ptosis, diplopia, dyspnea, dysphagia and difficulty in talking [4].

The paralysis then symmetrically descends to involve the limbs causing weakness of the arms and legs. There may also be a diminishing or even a total absence of the reflexes. As the disease progresses, it may also cause paralysis of the muscles of respiration leading to respiratory arrest which can be life threatening.

Constipation is an early symptom in infant botulism which is most likely to be missed.

Most of the cases of infant botulism should be diagnosed on clinical grounds. Confirmation can be made by stool or enema specimen with the mouse bioassay.

In all other forms, the diagnosis of botulism can be based on the patient’s history and physical examination; however, the signs and symptoms may mimic other diseases like Guillain-Barré syndrome, stroke and myasthenia gravis [5].

Confirmation of diagnosis can be made if botulinum toxin is identified in the food, stomach contents, vomitus and/or feces of the patient. In peracute cases, the toxin can be found in blood as well. The detection of toxin in various specimens can be carried out by different tests such as:

• Enzyme-linked Immunosorbent Assays (ELISA)
• Electrochemiluminiscence (ECL) [6]
• Mouse inoculation tests

The primary treatment consists of administration of antitoxin and the provision of supportive care [7].

In case of respiratory paralysis, the patient may require a ventilator for weeks or months. Food borne and wound botulism, if diagnosed early, can be treated with passive immunity and antibiotics [8].

Two types of antitoxins are available:

• trivalent antitoxin (effective against the toxin types A, B and E) [9]
• heptavalent antitoxin (effective against all the toxin types from A to G) [10]

Infant botulism is harder to manage. Currently, a drug named Botulism Immune Globulin Intravenous (Human) is the only suitable option to manage this form of botulism.

Untreated botulism may be fatal in as many as 60% of the cases. However, if diagnosed early, the disease can be successfully treated with no complications.

The recovery however, may still take some weeks. Before the development of artificial respirators, mortality due to botulism was very high, but in 1990s it dropped to as low as 2%.

Botulism is caused by the toxin produced by the bacterium Clostridium botulinum and not by infection with the bacterium itself. The organism produces toxin in anaerobic conditions. The toxin enters the bloodstream and acts on the nervous system causing flaccid paralysis of voluntary muscles which may progress to paralysis of respiratory muscles leading to respiratory arrest.

The disease in humans in mostly caused by three toxin types A, B and E. The lethal doses for causing disease in a man of 70 kg weight are estimated to be 0.09 to 0.15 micrograms intravenously, 0.80 to 0.90 micrograms through inhalation and 70 micrograms orally.

Food borne Botulism

This form of botulism occurs when food containing botulinum toxin is consumed. In conditions of environmental stress, the bacteria form spores which are resistant to cooking. Later, when they receive a favorable environment (e.g. one that has an alkaline pH and a low salt & sugar content), they produce botulinum toxin. This mostly occurs in improperly preserved foods.Symptoms appear 12 to 36 hours after eating such contaminated food.

Infant Botulism

This is the type of botulism which occurs due to colonization of the bacteria in the intestines. The bacteria produce toxins which are absorbed from the intestinal wall into the bloodstream. It most commonly occurs in infants of the ages of 2 to 3 months. This is because by that age, their normal intestinal flora have not been fully established. Normally, the intestinal flora compete with Clostrodium botulinum, preventing it from actively colonizing the intestine. Honey consumption in infants is regarded as the most common cause of infant botulism [2].
Adult form of infant botulism is termed as adult intestinal toxemia but it is exceedingly rare.

Wound Botulism

Wound botulism occurs as a result of contamination of a wound by either the bacteria or its spores. The toxin produced by them then enters the bloodstream. Nowadays, intravenous drug use is a very common cause of this form of botulism [3].

Inhalation Botulism

It is a very rare kind of botulism. Some cases have been reported due to the accidental inhalation of Clostridium botulinum spores by laboratory workers.

Globally, botulism is not a very common disease. Most of the cases are sporadic, although sometimes outbreaks have occurred in certain areas of the United States and the United Kingdom.

The Centers for Disease Control USA has documented 263 individual cases during the years 1990 to 2000; 163 of which happened to be of the food borne variety. The average number of cases of food borne botulism in the United States is estimated to be 24 cases per year - most of which occur in Alaska [1].

There are about 80 to 100 cases of infant botulism annually in United States, making it the most common form of botulism. About 20% of these occur due to the consumption of honey in children below one year of age.The largest incidence of infant botulism has been found to be in Philadelphia and Pennsylvania.

Wound botulism occurs due to trauma and its incidence is on the rise since 1990s due to increased use of intravenous drugs and skin popping.

The bacterium Clostridium botulinum produces eight types of toxins (A, B, C1, C2, D, E, F, and G). These toxins are serologically different but produce similar symptoms in the patients. The toxin types A, B and E cause disease in humans.

In all forms of botulism the toxin affects the nervous system. Once it is absorbed in the bloodstream it is carried to the peripheral cholinergic synapses specially that of the neuromuscular junctions where it inhibits the release of acetylcholine from the nerve terminals by irreversibly binding to the acetylcholine receptors.

This neurotransmitter produces a bridge between synapses where dendrites and axons connect with each other. The toxin enzymatically blocks acetylcholine release from the motor nerve endings which results in paralysis.

There are no guidelines for prevention of Botulism.

Botulism is a rare but potentially lethal condition caused by a spore-producing gram positive bacterium Clostridium botulinum that naturally occurs in the soil. The organism produces botulinum toxin which causes neuromuscular flaccid paralysis.

Depending upon the route of entry of the bacteria or its toxin, botulism can be divided into several types; namely food-borne botulism, infant botulism, wound botulism, and the less common, inhalation botulism.

The disease begins with fatigue, blurring of vision and diplopia followed by the weakness of motor function throughout the body and difficulty in breathing.

If diagnosed early, it can be treated by providing passive immunity, although complete recovery may take weeks to months.

Botulism is a rare but fatal disease caused by a bacterium that is normally found in the soil. It is characterized by paralysis of the muscles of the face, arms, legs and chest (including the muscles required for breathing).

It usually results from eating food that is contaminated with the toxin. This condition is treated by the injection of appropriate antitoxins. In cases that are diagnosed early, the prognosis is quite good.

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