Prognosis of rabies virus

If you're traveling to a country where rabies is common and you'll be there for an extended period of time, ask your doctor whether you should receive the rabies vaccine. This includes traveling to remote areas where medical care is difficult to find. Mayo Clinic does not endorse companies or products.

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Overview Rabies is a deadly virus spread to people from the saliva of infected animals. Mayo Clinic Minute: What you should know about bats and rabies. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Rabies. Centers for Disease Control and Prevention. Accessed Aug. Mayo Clinic; Elsevier Point of Care. Rabies vaccine information statements. Bennett JE, et al. Rabies Rhabdoviruses. Elsevier; The laboratory results may save a patient from unnecessary physical and psychological trauma, and financial burdens, if the animal is not rabid.

In addition, laboratory identification of positive rabies cases may aid in defining current epidemiologic patterns of disease and provide appropriate information for the development of rabies control programs. The nature of rabies disease dictates that laboratory tests be standardized, rapid, sensitive, specific, economical, and reliable. Skip directly to site content Skip directly to page options Skip directly to A-Z link. Section Navigation. Facebook Twitter LinkedIn Syndicate.

How is rabies diagnosed? Minus Related Pages. 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.

One of the most rapid methods to diagnose rabies antemortem in humans is to perform a direct immunofluorescence test on a skin biopsy from the nape of the neck for evidence of rabies antigen. The direct immunofluorescence test is the most sensitive and specific method of detecting rabies antigen in skin and other fresh tissue e.

If fresh tissue is unavailable, enzyme digestion of fixed tissues may enhance the reactivity of the immunofluorescence test; however, sensitivity may be unacceptably low. The diagnosis can also be established if virus is isolated from saliva after inoculation of neuroblastoma cells or laboratory rodents; this is generally most successful during the first 2 to 3 weeks of illness.

The detection of rabies virus-neutralizing antibody, as typically performed by the rapid fluorescent focus inhibition test RFFIT , in the serum of unvaccinated individuals is also diagnostic. The presence of antibody in the cerebrospinal fluid confirms the diagnosis, but it may appear 2 to 3 days later than serum antibody and may there fore be less useful early in the disease. Whereas the serological response after vaccination cannot be generally differentiated from that due to disease, vaccination does not typically produce cerebrospinal fluid antibody.

Although rabies virus was not isolated in any of the patients, the high rabies-neutralizing antibody titer in serum samples and the presence of neutralizing antibodies in cerebrospinal fluid strongly supported the diagnoses. Animal rabies is prevented by vaccinating susceptible species, particularly dogs and cats. Mass dog vaccination programs in the United States and Europe were largely responsible for a dramatic reduction in canine and human rabies during the 's and s.

In these countries, the number of reported cases in wildlife is currently about fold greater than that in domestic animals; wildlife therefore constitute the greatest risk to human beings. Oral vaccination of wildlife with attenuated and recombinant rabies vaccines by the use of vaccine-containing bait offers hope of controlling the disease in susceptible wild free-ranging animal populations.

Human rabies is best prevented by avoiding exposures to the disease. When an exposure is suspected, the patient's physician and local health department authorities should determine whether an exposure actually occurred and whether a risk of rabies exists in the geographic area Table If treatment postexposure prophylaxis is necessary, it should be initiated promptly. Postexposure prophylaxis consists of the combination of local wound cleansing, human rabies immune globulin HRIG and rabies vaccine.

Postexposure treatment will abort the infection Table , but there is no cure for clinical disease. Preexposure immunization may be offered to persons at high risk Table , such as veterinarians, animal handlers, certain laboratory workers, and persons spending time e.

Persons, such as spelunkers, whose vocational or recreational pursuits bring them into frequent contact with potentially rabid animals should also be considered for preexposure prophylaxis. The schedules for preexposure prophylaxis are given in Table Turn recording back on. National Center for Biotechnology Information , U. Show details Baron S, editor. Search term. General Concepts Clinical Manifestations Rabies virus causes acute infection of the central nervous system.

Structure Rabies virus is a rod- or bullet-shaped, single-stranded, negative-sense, unsegmented, enveloped RNA virus. Classification and Antigenic Types Placement within the family is based on the distinctive morphology of the virus particle. Multiplication The viral RNA uncoats in the cytoplasm of infected cells. Pathogenesis After inoculation, rabies virus may enter the peripheral nervous system directly and migrates to the brain or may replicate in muscle tissue, remaining sequestered at or near the entry site during incubation, prior to central nervous system invasion and replication.

Host Defenses Susceptibility to lethal infection is related to the animal species, viral variant, inoculum concentration, location and severity of exposure, and host immune status. Epidemiology Rabies occurs in nearly all countries.

Diagnosis Early diagnosis is difficult. Control Vaccination of susceptible animal species, particularly dogs and cats, will control this zoonotic disease. Introduction The family Rhabdoviridae consists of more than single-stranded, negative-sense, nonsegmented viruses that infect a wide variety of hosts, including vertebrates, invertebrates, and plants.

Clinical Manifestations Five general stages of rabies are recognized in humans: incubation, prodrome, acute neurologic period, coma, and death or, very rarely, recovery Fig. Figure Pathogenesis of rabies. Figure Virion structure of rabies virus. Figure Genome of rabies virus ERA strain. Classification and Antigenic Types 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.

Multiplication The replication of rabies virus is believed to be similar to that of other negative-stranded RNA viruses.

Pathogenesis Rabies virus is most commonly transmitted through the bite of an infected mammal, all of which may be susceptible, but to greatly varying degrees. Host Defenses 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. Epidemiology Rabies has been recognized for over 4, years. Figure Life cycle of rabies.

Diagnosis Differential Diagnosis The diagnosis of human rabies is usually suggested by epidemiologic and clinical findings and confirmed in the laboratory. Laboratory Diagnosis The detection of rabies antigen, antibody, viral RNA, or the isolation of virus establishes a diagnosis of rabies. Control Animal rabies is prevented by vaccinating susceptible species, particularly dogs and cats.

References Baer GM. Kluwer Acad Publ, Boston, Centers for Disease Control: Compendium of animal rabies control,