Rabies is a very terrible disease. Once it occurs, the mortality rate is almost 100%. In this article, we will introduce the basic knowledge of rabies to let you understand rabies.
What is rabies?
Rabies is an acute infectious disease caused by rabies virus . It is zoonotic. It is more common in carnivores such as dogs, wolves, and cats. People are mostly infected by bites by sick animals. Clinical manifestations include unique fear of water and wind, pharyngeal muscle spasm , progressive paralysis, etc. Because the symptoms of water fear are quite prominent, this disease is also known as water fear .
What are the symptoms of rabies?
clinical process of typical cases can be divided into the following 3 periods:
01
predrought or invasion period
Before the excited state appears, most patients have low fever, appetite deficiency, nausea, headache, fatigue, and discomfort, which is very similar to "cold"; then they appear fear and uneasy, are more sensitive to sound, light, wind, pain, etc., and have a sensation of throat tightness. The most diagnostic early symptoms are abnormal sensations in the wound and its surroundings, including itching, numbness, pain, and the feeling of ant walking. This period lasts for 2-4 days.
02
excitation period
patients gradually enter a state of high excitement, which are prominently manifested as extreme horror, fear of water, wind, onset pharyngeal muscle spasm, difficulty breathing, difficulty in urination and defecation, and sweating and salivation. Water fear is the most specific symptom, which is caused by pharyngeal muscle spasm, but it may not occur in every case, nor may it occur in the early stages.
Typical patients can cause severe pharyngeal muscle spasm when they see water, hear the sound of running water, drink water, or only mention drinking water. patients are extremely thirsty and dare not drink, and they cannot swallow even after drinking, and are often accompanied by hoarseness and dehydration.
Fear of wind is also one of the common symptoms, and Breeze can also cause pharyngeal muscle spasm. Other stimuli such as light, sound, touch, etc. can cause the same attack. In severe attacks, painful convulsions may occur throughout the body.
Due to frequent respiratory muscle spasms, it can lead to dyspnea and cyanosis. Patients may also experience hypersympathetic nervous system such as increased saliva secretion, , sweating profusely, heart rate, blood pressure and body temperature. It is also quite common for people with urination and difficulty in defecation due to sphincter dysfunction. Most patients are clear about their consciousness. Although they are extremely afraid and irritable, they rarely act incitement.
As the excitatory state increases, some patients may experience mental disorders, delirium, auditory hallucinations, collision and howling. The course of the disease progresses very quickly, and many patients die from respiratory failure or circulatory failure during the attack. This issue lasts for 1-3 days.
02
paralysis period
spasm stops, and the patient gradually becomes quiet, but retarded paralysis occurs, especially retarded paralysis (relief paralysis) of the limbs. Eye muscles, facial muscles and chewing muscles can also be affected, which are manifested as strabismus , eye movement disorders, jaw drop, mouth cannot be closed, and facial expressions are missing.
The breathing of patients gradually becomes weak or irregular, and tidal breathing may occur; the pulse is fine, blood pressure drops, reflexes disappear, and pupils are dilated, and they may die quickly due to respiratory and circulatory failure. Before death, patients often fall into coma. This period lasts 6-18 hours.
The entire course of rabies is generally not more than 6 days, and occasionally more than 10 days are seen.
In addition to the above typical cases, there are also "paralytic" or "quiet" with paralysis as the main manifestation, also known as "dumb rabies", accounting for about 20%. This type of patient has no excitation period or water fear, but starts with high fever, headache, vomiting, and pain in the bite, and then develops limb weakness, abdominal distension, ataxia, muscle paralysis, incontinence, etc.
course can last up to 10 days, and eventually dies due to respiratory muscle paralysis and medulla oblongata. Vampire bat rabies often belong to this type.
How long is the incubation period of rabies?
Incubation period vary, most of which are within 3 months, and the domestic report averages of 66.9 days. The incubation period of 4%-10% of patients exceeds six months, 1% exceeds one year, and 7 years have been reported; the length of the incubation period is related to factors such as age (short children), wound site (head and facial injuries occur earlier, with an average of 39 days, and lower limb injuries sufferers with an average of 90 days), wound depth (short incubation period for deep patients), number of invading viruses and virility (short incubation period for strong virility). Other factors such as incomplete expansion, trauma, cold, and overwork may cause the disease to occur in advance.
Why is the mortality rate of rabies so high?
Rabies is a neurophilic virus. After the virus invades from the bite site, it gathers and reproduces at the nerve fibers of the striated muscle shuttle receptor in the wound, and then invades the nearby peripheral nerve . The virus spreads along the peripheral nerves to the dorsal root ganglion, reproduces in large quantities, and then invades neurons in the spinal cord, brain and cerebellum.
Because the rabies virus replicates in central nervous system , it only takes 24 hours from entering the brain to completely destroying the central nervous system. The human immune system has no time to respond and the patient has died. So far, rabies lacks effective treatment methods and there are no drugs to fight rabies virus. Therefore, once rabies occurs, the mortality rate is almost 100% . How to inject rabies vaccine from
?
Are people at a loss about it? We can inject rabies vaccine to high-risk patients. The injection of
rabies vaccine can be divided into post-exposure vaccination and pre-exposure prevention.
1 Inoculation after exposure : Whether to be vaccinated after exposure depends on the level of exposure.
I-level exposure : refers to contacting, feeding animals, or intact skin being licked by animals.
II exposure : The exposed skin is lightly bitten or slightly scratched or scratched by animals, but there is no bleeding.
III exposure : One or more skin is bitten, scratched, or mucous membrane is contaminated by saliva, the skin on the animal's licking touch is damaged, or the exposure is related to bat .
For Class I exposure, no precautionary measures are required. Class II exposure should be vaccinated immediately; in addition to getting vaccinated immediately, Class III exposure also requires rabies immunoglobulin.
"Healthy" poisoned dogs are widely present in China. Except for those exposed in Level II and III, who should be vaccinated, the skin licked during Level I exposure should be carefully identified whether the skin is indeed damaged. If there are tooth marks on the skin, do not be careless. There may be skin damage that is difficult to detect with the naked eye. Rabies virus may invade the human body along the tooth mark.
Therefore, the bitten area should be disinfected immediately, thoroughly clean the tooth marks with soapy water, apply iodine wine, and then inject rabies vaccine throughout the process. Do not take it lightly if the anal mucosa is licked.
rabies vaccination sequence
Vero cell electric vaccine injection : 0 days after bite prevention (on the same day), 3 days, 7 days, 14 days, 30 days; 0 days without bite prevention (on the same day), 7 days, 21 days. Each time, 1.0ml (1ml for domestic production and 0.5ml for French production), there are suggestions to strengthen it once on the 90th day. It is advisable to have the deltoid muscle above the injection site. Children under 2 years old can inject the lateral thigh.
gopher kidney vaccine injection : Injection once on days 0, 3, 7, 14 and 30, the dose is the same as above.A few of them have pain, redness, swelling, nodules, itching, and even edema, lymph node swollen , etc. Refined VERO cell rabies vaccine and refined gopher kidney cell vaccine, because the vaccine has been purified, there are very few impurities, and the side effects of vaccination are rare or mild.
Rabies immunoglobulin can neutralize rabies virus and should be used immediately after injury. my country produces horse serum, each 10ml, containing 1000IU, 20ml for adults, and 40IU/kg for children. Take half of the dose for wound injection, and the other half will be intramuscular injection, but the injection site should be kept away from the vaccine injection point to avoid affecting the effectiveness of the vaccine.
How to prevent pre-exposure?
Pre-exposure prevention is suitable for veterinary dog doctors, animal managers, rabies virus researchers, bats that may carry rabies virus frequently, raccoons , skunks, cats, dogs, etc., and for bat-related management and researchers and medical staff in rabies wards. The immunization regimen of
is to inject one dose of vaccine each on the 0th, 7th and 28th, strengthen it once a year, and every 1-3 years later. It can also be determined based on the neutralizing antibody level. If the titer is above 0.5 IU/ml, it can not be strengthened. The injection will be given after follow-up to 0.5 IU/ml.
Image source: Photo Network
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