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Germs that infect humans

Rubella virus

Rubella virus

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

Microorganism: rubella virus, which is part of the family Togaviridae

Disease: rubella or German measles

Occurrence of the disease

History: rubella was first described in the 1800s in Germany. An epidemic occurred in the United States in 1964-1965. In the course of this epidemic 30,000 fetuses died and more than 20,000 infants were born with cardiac problems, mental retardation, or visual or hearing defects. Massive vaccination campaigns were started in 1968.

Current situation: 168 cases of rubella were reported in Canada in 1998.

Mechanism of action of the microorganism: the virus multiplies in the respiratory system. It is then able to migrate through the bloodstream or the lymphatic system to the skin.

Symptoms of the disease: small red spots, fever, and eventually discomfort in the joints of the fingers, wrists, and knees.

Infection with rubella in the early stages of pregnancy may have serious consequences for the baby. Congenital malformations may result and the fetus is at risk of dying. All women should check their immunization status against rubella before attempting to become pregnant. In the United States fewer than ten cases of rubella-related congenital malformations are reported per year.

Incubation period: between 12 and 23 days.

Contagious period: the contagious period lasts from one week before to four days after the appearance of the skin rash.

Hosts: humans

Transmission: this is a very contagious disease. The virus is spread in drops of saliva from infected persons.

Treatment: none – rubella is a minor infection.

Geographical distribution of the microorganism: worldwide

Prevention: vaccine

Vaccine: the rubella vaccine is derived from an attenuated virus. This vaccine is combined with the vaccines against measles and mumps in a vaccine called MMR. Children are injected with this vaccine at 12 and 18 months. Ninety-nine per cent of those who have been vaccinated with the recommended doses are protected against rubella.