Botulinum food poisoning, also known as botulism, is a toxic disease caused by eating food containing botulinum exotoxin. The main clinical manifestations are nausea, vomiting and central nervous system symptoms such as paralysis of the eye and pharyngeal muscles.
Clostridium botulinum, also known as Clostridium difficile, is a Gram-positive anaerobic clostridium, a neurotoxin, highly toxic, lethal to humans is about 0.01mg, the toxin is resistant to gastric acid, but not heat-resistant. 80 ℃, 5 minutes to destroy the type A toxin, type B toxin 88 ℃, 15 minutes to destroy. The toxin can be stored for many years under dry, sealed and dark conditions. Due to the strong toxicity of this toxin, and colorless, odorless, tasteless, not easy to detect, must pay attention to prevention.
Transmission channels
1.Infection source
Livestock, poultry and fish as the source of infection. The bacterium bacillus is widely distributed in nature, the germ by the animal (mainly herbivores) intestinal discharge, contamination of soil and shore sand soil, which contaminates drinking food canning, such as inadequate heating, the bacillus produced is not destroyed, coupled with the anoxic environment, resulting in a large number of Clostridium botulinum multiply, producing large amounts of exotoxin.
2, the transmission route mainly through food transmission, poisoning food types are.
①Fermented soybean products: stinky tofu, bean paste, stinky tempeh, moldy tofu, tofu dregs, pea paste, broad bean paste, red bean paste, moldy beans, etc.
② fermented flour products: corn flour sauce, wheat bran sauce, sweet pasta sauce, rice fluffy sauce, soybean sauce, etc.
③ animal food: and not fresh cured meat, smelly lamb, cooked lamb head meat, bad pork, dead donkey meat, mutton, pork, rotten eggs stinky fish, salted fish, bacon, dried beef, dried horse meat, roast beef, etc.
④ Others: pickled river beans, rotten potatoes, moldy corn, etc.
The process of these foods are equipped with.
① food raw materials are still local products, all have the possibility of contamination by Clostridium botulinum budding cells (especially toxin-producing strains).
② basically in an anaerobic fermentation state.
③ Placement of the fermented food at an ambient temperature between 25 and 35°C (placed next to a fire wall or on a bed).
④After the bean paste is made, the addition of another small amount of salt and seasoning cannot change the nature of the bean paste.
The reproduction of Clostridium botulinum does not necessarily require strict oxygen deprivation conditions and appropriate temperature, E type bacteria can reproduce at 6 ℃ low temperature and produce toxins; A type and B type bacteria can produce protein hydrolytic enzymes, so that food deterioration; while E type bacteria do not produce this enzyme, food can not deteriorate, easy to neglect and cause disease.
In the war environment, the enemy can use botulinum toxin spread by aerosol, widely contaminated drinking water, food and utensils, if not handled in time, can cause collective poisoning.
3.Susceptibility Universal susceptibility, does not cause human-to-human transmission.
Morbidity characteristics
The scope of botulism is determined by the spread of food containing botulinum toxin. In China, there are two forms of botulism poisoning: collective outbreaks, where most workers and their families eat the same poisonous food in a cafeteria, resulting in the poisoning of dozens of people or more. For example, in 1960, Qingdao City had a collective outbreak of 450 people eating steamed canned meat, resulting in 75 people being poisoned by botulism. This is also a rare case of botulism in China in the past 30 years. The onset of fermented soybean products or fermented noodles is often homemade by a housewife, and since fermented soybean products are mostly small amounts of food for meals, the onset of the disease is sporadic and occurs at different times, unlike other food poisonings where multiple people have the same nature and type of clinical manifestations in a short period of time. Some housewives unintentionally give toxic fermented soybean products to their neighbors, causing them to be poisoned as well. Therefore, the spread of the poisoned food also leads to the spread of the disease. This kind of morbidity characteristic is still the main and most common feature of botulism poisoning in China at present.
[Pathogenic pathology
Botulinum toxin is a neurotoxin, which is mainly absorbed by the upper gastrointestinal tract. After entering the small intestine and colon, the toxin is slowly absorbed, and gastric acid and digestive enzymes cannot destroy it, so most patients have a slow onset and a long course of illness. After absorption, botulinum toxin mainly acts on cranial nerve nuclei, peripheral nerves, muscle junction and vegetative nerve endings, blocking the conduction of cholinergic nerve fibers, nerve impulses are blocked at the presynaptic nerve endings, thus inhibiting the release of acetylcholine, a nerve conduction mediator, and causing muscle contraction and movement disorders, resulting in flaccid paralysis, but the muscle can still maintain its responsiveness to acetylcholine. The intravenous acetylcholine can restore the function of paralyzed muscles.
The pathological changes are mainly degenerative changes in the nucleus of the cranial nerve and the anterior horn of the crista medullaris, causing paralysis of the corresponding muscle groups innervated by them, and the nucleus of the brainstem nerve may also be damaged. The brain and meninges are markedly congested and edematous, with extensive punctate hemorrhage and thrombosis. Ganglion cell degeneration can be seen microscopically.
[Clinical manifestations
The incubation period is 12~36h, the shortest is 2~6h, the longest is 8~10d. The higher the dose of poisoning, the shorter the incubation period and the more severe the disease.
The onset of the disease is sudden, with headache, dizziness, vertigo, weakness, nausea, vomiting (E type bacteria nausea and vomiting is heavy, A type bacteria and B type bacteria are lighter); later, the internal and external muscles of the eyes are paralyzed, and eye symptoms appear, such as blurred vision, diplopia, drooping eyelids, dilated pupils, and loss of light reflex. The oral cavity and pharynx are flushed with sore throat, and if the pharyngeal muscles are paralyzed, it causes difficulty in whistling. Hypotonia is mainly seen in the neck and proximal extremities. The head is tilted forward or to one side due to weakness of the cervical muscles. The tendon reflexes may be symmetrically weakened.
The plant nerve endings are first excited and then inhibited, so the secretion of lacrimal glands, sweat glands and salivary glands increases first and then decreases. Blood pressure is first normal and then increases. The pulse rate is first slow and then fast. There is often intractable constipation, abdominal distention and urinary retention. During the course of the disease, the consciousness is clear, the sensation is normal, and there is no fever. There is no abnormal change in blood, urine and cerebral crest fluid routine examination. In mild cases, the patient gradually recovers within 5-9 days, but general weakness and ocular muscle paralysis persist for a longer period of time. Most of the critically ill patients die without timely resuscitation, with a death rate of 30-60%. The causes of death are mostly whistling failure due to medullary paralysis, cardiac insufficiency and secondary infection due to aspiration pneumonia.
Occasionally, infants swallow a small amount of botulinum bacilli, multiplying in the intestine, producing neurotoxins, which can be absorbed and cause sudden death due to sudden inhalation paralysis (sudden infant death syndrome, SIDS).
Diagnosis basis
1, there is a history of eating suspicious food, especially ham, salami, canned or bottled food, the same meal with a collective onset, the incubation period of the shortest 2 hours, the longest 14 days, mostly 12-16 hours.
2. The clinical manifestations are dominated by motor nerve paralysis symptoms in the cranial and crestal medulla, gastrointestinal symptoms are not obvious, consciousness is always clear, and sensation is not affected. Special neurological symptoms and signs, such as diplopia, strabismus, eyelid ptosis, dysphagia, whistling difficulties, etc.
3. Clostridium botulinum type A, B or E can be isolated in the stool of patients in the onset phase.
4. Botulinum exotoxin can also be detected in the serum of patients at the onset of the disease. Confirmation of diagnosis can be done by animal testing to check the botulinum toxin in the patient’s serum and suspected food, and also by using suspected food for anaerobic culture to isolate the pathogenic bacteria. In the war environment, the enemy must be alert to the application of aerosols containing botulinum toxin; if suspicious, the aerosol can be washed off from the place of attachment and animal testing can be conducted.
1.Animal test.
(1) take early serum injected into the abdominal cavity of mice (or guinea pigs, kittens), 1 ml of each mouse, the control group were added with A, B, E, F-type antitoxin, if botulinum toxin, the mice have difficulty in inhalation and wasp waist (waist concave like bees) and loss of voice, but the addition of the same type of antitoxin without symptoms.
(2) Take the suspicious food saline leach filtrate, inject into the abdominal cavity of mice with the above method, and observe the results, in addition to the leach filtrate inactivated by heating at 100 ℃ for 20 minutes as a control.
(3) Avian eyelid injection method, the specimen liquid 0.1 ~ 0.5 ml injected into the lower eyelid of chickens, sparrows or pigeons, such as subcutaneous, the other side of the injection diluted with liquid for control. If the eyelid is closed, it can be determined that the specimen contains botulinum toxin. Depending on the amount of toxin in the specimen, the detection time varies from ten minutes to 48h. If different types of antitoxin are added to the specimen, it can be used to determine the type of toxin.
2.Indirect hemagglutination test The specificity and sensitivity of the red blood cells sensitized with botulinum toxin to check the presence of toxin in the suspected food leachate are very high.
Differential diagnosis
Differentiate from cremasteric poliomyelitis, post-diphtheria neuropathy, epidemic B encephalitis, acute polyneuritis, mushroom and staphylococcal enterotoxin poisoning, etc.
Treatment
1, antitoxin treatment antitoxin treatment polyvalent botulinum toxin (A, B, E type) on the disease has special effects, must be applied early, within 24 hours after the onset of the disease or paralysis before the occurrence of the most effective injection, the dose of 5 ~ 100,000 units each time, intravenous or intramuscular injection (first serum sensitivity test, allergy first desensitization treatment), if necessary, 6h after the same amount of repeatedly given once. In cases where the type of pathogen has been determined, the same type of antitoxin should be injected, 1~20,000 units each time. If the course of the disease has passed two days, the antitoxin effect is poor, but the injection should be continued to neutralize the residual toxin in the blood.
2. Symptomatic treatment Patients should be strictly bed rested and given appropriate sedatives to avoid aggravation of paralysis. Patients can use 5% sodium bicarbonate or 1:4000 potassium permanganate solution for gastric lavage and enema within 4h after eating to destroy the toxins not yet absorbed in the stomach and intestines. Nasal feeding and fluid infusion are recommended for pharyngeal muscle paralysis. Oxygen is administered to those who have difficulty in whistling, tracheotomy is performed early, and an artificial whistle is used for whistling paralysis. In order to destroy Clostridium botulinum in the intestine and prevent it from continuing to produce enterotoxin, high doses of penicillin can be given. Measures such as cardiac stimulants and prevention of secondary bacterial infections should also be given according to the condition. Physical labor should be avoided for 10 to 15 days after discharge from the hospital.
3, chemotherapy In recent years, guanidine hydrochloride 35-50mg/kg/d in 4-6 oral doses has been used. It is reported to have the effect of promoting the release of acetylcholine from peripheral nerve fibers, thus improving the neuromuscular transmission function, increasing muscle tone and relieving the symptoms of poisoning.
Prevention
Strict management and inspection of food, especially attention should be paid to the production and preservation of canned food, ham and preserved food. If the ends of canned food are puffed up or the color and flavor of the contents change, it should be prohibited from sale and consumption, and should not be consumed even if boiled. Cereals and beans also have the possibility of contamination by Clostridium botulinum, so it is prohibited to eat fermented or rotten food.
In the case of war, we should be careful not to contaminate drinking water with aerosols of botulinum toxin spread by the enemy, causing collective poisoning. In case of botulinum toxin poisoning in fellow eaters, the rest of the personnel should be immediately given polyvalent refined botulinum toxin antitoxin for prevention, 1000 to 2000 u subcutaneously, once a week, three times in total. Those who frequently consume canned food may consider injection of antivenom for prevention.