Causes of rabies virus

List of Partners vendors. Table of Contents View All. Table of Contents. Common Risk Factors. Outside the United States. Reducing Your Risk. Next in Rabies Guide. Frequently Asked Questions Is rabies caused by bacteria? What animals are most likely to carry rabies? How Rabies Is Diagnosed. Was this page helpful? Thanks for your feedback! Sign Up. What are your concerns? Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles.

Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Related Articles. Can a Cat Scratch Be Dangerous? Transcription synthesis of mRNAs. Translation Synthesis of structural proteins. Processing G-protein gycosylation.

Replication production of genomic RNA from intermediate strand. Skip directly to site content Skip directly to page options Skip directly to A-Z link. Section Navigation. Facebook Twitter LinkedIn Syndicate. What is Rabies? Minus Related Pages. Structure Rhabdoviruses are approximately nm long and 75 nm wide. Replication The fusion of the rabies virus envelope to the host cell membrane adsorption initiates the infection process.

Rabies in the Americas external World Rabies Day. Genome of rabies virus ERA strain. The genus Lyssavirus includes rabies virus and the antigenically- and genetically-related rabies- like viruses: Lagos bat, Mokola, and Duvenhage viruses, and two suggested subtypes of European bat lyssaviruses.

Cross-protection studies suggest that animals immunized with traditional rabies vaccines may not be fully protected if challenged with other lyssaviruses. Rabies viruses may be categorized as either fixed adapted by passage in animals or cell culture or street wild type. The use of monoclonal antibodies and genetic sequencing to differentiate street rabies viruses has been helpful in identifying viral variants originating in major host reservoirs throughout the world and suggesting the likely sources of human exposure when a history of definitive animal bite was otherwise missing from a patient's case history.

The replication of rabies virus is believed to be similar to that of other negative-stranded RNA viruses. The virus attaches to the host cell membranes via the G protein, penetrates the cytoplasm by fusion or pinocytosis, and is uncoated to RNP. Each RNA is then translated into an individual viral protein. After viral proteins have been synthesized, replication of the genomic RNA continues with the synthesis of full length, positive-stranded RNA, which acts as a template for the production of progeny negative-stranded RNA.

Rabies virus is most commonly transmitted through the bite of an infected mammal, all of which may be susceptible, but to greatly varying degrees.

The virus may enter the peripheral nervous system directly, or may replicate in muscle tissue after entering the host, remaining at or near the site of introduction for most of the incubation period. However, the precise sites of viral sequestration remain unknown, since neither antigen nor virus can usually be found in any organ during this phase. Virus may enter the peripheral nervous system via the neuromuscular junctions, and moves rapidly centripetally to the central nervous system for replication; symptoms may develop shortly thereafter.

The virus then begins to pass centrifugally to many tissues and organs, such as the salivary glands. In general, gross examination of the brain shows mild congestion of the meningeal vessels; microscopic examination usually demonstrates slight perivascular cuffing, limited tissue necrosis, acidophilic intracytoplasmic neuronal inclusions, and rarely, neuronophagia. The host animal species, viral variant, inoculum concentration, body location and severity of exposure, and host immune status have been associated with overt susceptibility to infection and with different incubation periods.

The association of virus-neutralizing antibody, principally IgG, and protective immunity is well known. Production of cytokine, such as interferon, induced during rabies virus infection or vaccination, has been reported to abort the disease if it occurs shortly after viral infection.

In one clinical trial, however, all subjects died despite experimental treatment with high doses of alpha interferon. Recently it has been demonstrated that animals immunized with purified RNP complexes or recombinant nucleoprotein vaccines resisted lethal challenge with rabies virus, although the role of N protein in protection, illness, or recovery is unclear. Rabies has been recognized for over 4, years. Today it is found in most countries, with the exception of those regions from which it has not been naturally reported, including many Australian islands, or areas achieving secondary elimination, such as the United Kingdom.

Almost all human rabies is caused by the bite of a rabid animal Fig The risk of rabies is highest in countries with hyperendemic canine rabies, including most of Asia, Africa, and Latin America. Wildlife rabies in the United States occurs primarily among wild terrestrial carnivores, such as raccoons, skunks, foxes, and coyotes, and in insectivorous bats.

Human rabies is almost always attributable to a bite any penetration of the skin by the teeth. Nonbite exposures contamination of an open wound or a mucous membrane via scratches, licks, and inhalation of aerosol rarely cause rabies in humans. Of these five human cases, four were apparently attributable via exposure to aerosols containing highly concentrated live rabies virus: two in spelunkers cave explorers and two in rabies research laboratory workers. The fifth case occurred in the recipient of a cornea transplanted from a patient dying of unsuspected rabies encephalitis.

This may be attributable either to an inability of the patient to recognize actual rabies exposure at the time, or a failure to properly question the patient concerning potential animal contact. Although it is now a rare human disease in the United States, its actual incidence may be higher than generally believed. The initial suspicion of rabies only occurred at postmortem examination in five reported human cases in the United States since The diagnosis of human rabies is usually suggested by epidemiologic and clinical findings and confirmed in the laboratory.

The diagnosis is not difficult if there is a history of animal bite exposure and if a full spectrum of symptoms and signs has appeared. Otherwise, careful but rapid assessment of the epidemiologic and clinical features of less typical cases is essential before special laboratory tests are performed.

Every patient with neurologic signs or symptoms or unexplained encephalitis should be questioned about the possibility of animal exposure in a rabies-endemic area inside or outside the country of residence.

The failure to suspect rabies in several of the recent human deaths in the United States may have occurred because no thorough exposure history had been sought. Early in the course of illness, rabies can mimic numerous infectious and noninfectious diseases.

Many other encephalitides, such as those caused by herpesviruses and arboviruses, resemble rabies. Other infectious diseases also may resemble rabies, such as tetanus, cerebral malaria, rickettsial diseases, and typhoid. Paralytic infectious illnesses that may be confused with rabies include poliomyelitis, botulism, and simian herpes type B encephalitis.

Noninfectious diseases that may be confused with rabies encompass a number of neurologic syndromes, especially acute inflammatory polyneuropathy Guillain-Barre syndrome , as well as allergic postvaccinal encephalomyelitis secondary to vaccination with nervous-tissue rabies vaccines, intoxication with poisons or drugs, withdrawal from alcohol, acute porphyria, and rabies hysteria.

Guillain-Barre syndrome may be mistaken for the paralytic form of rabies, and vice versa. The detection of rabies antigen, antibody, viral RNA, or the isolation of virus establishes a diagnosis of rabies. Because any individual test may not be positive in a patient with rabies, serial serum specimens for detection of rabies antibodies, saliva specimens for culture of virus, and skin biopsies for direct immunofluorescence testing for virus antigen are sometimes necessary, especially when rabies is strongly suspected.

Poland says that's why if you wake up and find a bat in the room, you should get the rabies vaccine. Poland: "People think, 'Well, the bat's in the house. We woke up with it, doesn't look like it bit anybody. Rabies is such a severe disease with no cure, no treatment for it, that the safer thing to do is to give rabies vaccine. Jason Howland: That includes an immune globulin and multidose rabies series which is not cheap.

A typical series of rabies vaccines cost anywhere from three to seven thousand dollars. Seek immediate medical care if you're bitten by any animal, or exposed to an animal suspected of having rabies. Based on your injuries and the situation in which the exposure happened, you and your doctor can decide whether you should receive treatment to prevent rabies.

Even if you aren't sure whether you've been bitten, seek medical attention. For instance, a bat that flies into your room while you're sleeping may bite you without waking you. If you awake to find a bat in your room, assume you've been bitten. Also, if you find a bat near a person who can't report a bite, such as a small child or a person with a disability, assume that person has been bitten.

The rabies virus causes a rabies infection. The virus spreads through the saliva of infected animals. Infected animals can spread the virus by biting another animal or a person.