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Germs that infect humans

Rabies virus

Rabies virus

© Robert Alain, SME, INRS-Institut Armand-Frappier

Microorganism: a virus of the family Rhabdoviridae.

Disease: rabies

Occurrence of the disease

History: in 1885, Louis Pasteur became famous for using a vaccine he had developed to cure a young shepherd bitten by a rabid dog.

Current situation: rabies kills 35,000 to 40,000 people annually; most cases occur in developing countries. A single case of rabies, caused by a bat bite, was reported in Quebec in 2000. This was the first reported case in years.

Mechanism of action of the microorganism: the rabies virus multiplies in the salivary glands and eventually spreads to the muscles and nervous system. Once it reaches the brain, it produces masses known as Negri bodies. Because the virus grows in the salivary glands, it can be transmitted through bites.

Symptoms of the disease: anxiety, irritability, fatigue, depression, loss of appetite, and fever. More serious effects include muscle hypersensitivity, paralysis, convulsions and delirium. If untreated, the disease results in the destruction of the part of the brain responsible for the control of breathing.

Incubation period: three to eight weeks.

Contagious period: in cats and dogs, usually three to seven days.

Hosts: wild animals such as skunks, raccoons, bats, and foxes are the most common hosts for rabies, although cats and dogs may also act as hosts.

Transmission: rabies is transmitted through contact with the saliva or blood of infected animals, most commonly through bites.

Treatment: bites from rabid animals should be immediately washed with soap and water. Consult a hospital emergency department as soon as possible, to obtain vaccination against rabies. While vaccines are usually preventive rather than curative, the long incubation period of rabies allows this vaccine to actually prevent the development of the disease.

Geographical distribution of the disease: worldwide.

Prevention: vaccination of pets and, in some cases, immunization of wild animals through the use of oral vaccines. For example, a mass immunization program of wild animals around the Canada-United States border has been undertaken, using air-dropped food containing an oral vaccine.

Vaccine: inactivated vaccine.