What is the highest fatality rate in the world? The answer must include rabies virus. The fatality rate of rabies virus is 100%. Only Jeanna Giese has never been vaccinated against rabies and survived rabies. The few remaining cases have been vaccinated against rabies. Even the miracle of Jeanna Giese is doubtful because she was bitten by a bat rather than a dog.
Rabies virus belongs to the genus of rabies virus in the Rhabdoviridae family. The shape is slug, the nucleocapsid is spirally symmetrical, the surface has an envelope, and it contains single-stranded RNA. It is the pathogen that causes rabies. Rabies virus is a neurotropic virus-a natural killer of nerve tissue and nerve cells. It can infect all mammals, but it cannot infect birds, reptiles, amphibians and all other lower animals.
Although the name is rabies virus, its host is not only dogs, but also dogs, foxes, jackals (jackals), wolves, cats, skunks, minks, weasels, ferrets (ferrets) and ferrets, mongooses and Meerkats, raccoons, vampire bats, insectivorous bats, etc.
Of course, in terms of the number of people infected with rabies worldwide, dogs are the most important storage reservoir for rabies virus. Dogs as a source of infection account for 99% of human rabies, followed by cats.
The onset of rabies virus
How terrible is a rabies attack? It may only go through three processes before entering death.
1. Incubation period: After being bitten, the virus in the saliva often first touches the skin and muscles, and it is still a long way from the brain. The virus will slowly replicate first, grow the team, and wait for an opportunity to enter the nervous system.
The rabies virus enters the nervous system through the connection between the motor nerve and the skeletal muscle, and travels backward along the neuron, passes through the motor neuron, the dorsal root ganglia, and finally ascends to the brain. Once the rabies virus starts to infect the nervous system, it will be transported at a high speed between neurons, which is much faster than the reaction time of the human immune system. After the rabies virus invades the brain, the entire host’s nervous system will be fatally damaged.
2. Excitement period: Because the virus specifically attacks the brain tissue that controls swallowing and respiratory functions, the salivary nucleus, glossopharyngeal nucleus and hypoglossal nucleus related to this will be damaged, so the infected person will be affected by the sounds and light sources around them. Feel sensitive, because the nervous system is attacked, people will become extremely excited, and become more sensitive to external stimuli such as water and wind, especially water. “Water fear” manifestations appear in almost 80% of infected persons.
When you see the fierce and revealing eyes of the infected person at this time (both eyes condensing emotion), it actually signals the end of life. This shows that the virus has replicated in large numbers in the nervous system and caused irreversible damage. Although dynein has told the body’s immune army about the disappearance of the nervous system by this time, it is too late.
Because they are extremely sensitive to external stimuli, the infected person will also have extreme fear. Muscle cramps can be felt in the throat, and sometimes even the sound of water can cause laryngo cramps. The infected person will feel difficulty breathing, and some people will suffocate and die.
3. Paralysis period: Because the nervous system is damaged, people will have mental abnormalities and delirium, and they will attack others. Because breathing, heartbeat and other physiological activities are innervated by nerves, after the excitement lasts for 1 to 3 days, the nervous system is completely Resting the food, the convulsions and convulsions will stop, and a variety of slow paralysis symptoms will begin to appear, most commonly with soft limbs, and quickly enter a coma state, and finally die of respiratory, circulatory and systemic failure. After being infected with rabies virus, the time from illness to death generally does not exceed six days.
It can be said that if there is no vaccine, once an infected person becomes ill, there is no way to cure it, and the mortality rate is 100%. Vaccination is currently the only life-saving method. The role of the vaccine is to artificially give warnings, mobilize the immune army in advance, and eliminate the virus before it invades the nervous system.
How to confirm rabies virus infection
How can I confirm that I was infected with rabies virus after being bitten? The WHO recommendation is a 10-day observation method, because dogs carrying the virus are different from dogs with infectious diseases. Infectious dogs will die within 10 days (100% mortality), that is, dogs that bite will die within 10 days. The bitten person must be infected with the rabies virus, and the bitten dog will not die within 10 days. The bitten person must not get sick.
However, during the observation period, it is by no means to let people wait for a fluke, but to take corresponding measures according to the extent and location of the wound. Since the rabies vaccine injection needs to be divided into multiple and several weeks to complete, if the animal is safe after 10 days, then consider terminating the remaining vaccine injections.
It should be noted that healthy dogs will not transmit rabies virus (the pet dogs vaccinated with canines are generally healthy dogs), and the number of dogs in China is 75 million . According to a national survey in areas with high rabies incidence , my country’s canine vaccination rate is far below 70%, and the number of “healthy dogs” may be lower than people’s expectations. Therefore, the probability of dogs carrying rabies virus in our country is relatively higher than that in foreign countries. In the past 10 years, China has reported more than 2,000 rabies deaths every year. The peak in 2007 reached 3300 cases.
to sum up
But fortunately, as a viral infectious disease with a fatality rate of 100%, rabies virus spreads in a single way, and the transmission efficiency is also very low; diseased animals must get the opportunity to infect other susceptible animals in time before they die to maintain rabies. The virus continues to exist, otherwise the rabies virus and its host will die together, and the rabies virus will die out on its own in the animal group. Therefore, there are very harsh conditions for rabies virus to continue to exist in a certain animal group. The host group must reach a certain number and density, must be highly susceptible to rabies virus, and its behavior and ecological environment are suitable for rabies virus. Spread. This mode of transmission also restricted the rabies virus from becoming a large-scale infectious disease, and organized a global “pandemic” of the rabies virus.
There is considerable controversy surrounding rabies. But it is undeniable that human beings are still unable to defeat the rabies virus.