Virology

TOGAVIRIDAE FAMILY

Written by MicroDok

Togaviridae family comprises of viruses that are usually transmitted through arthropods such as insects. But some viruses in this family lack arthropod transmission. There are basically two genera of viruses in the Togaviridae family; and they are Alphavirus and Rubivirus. The viruses in the genera Alphavirus are basically transmitted to humans via arthropods especially blood-sucking mosquitoes while those in the genera Rubivirus lack arthropod transmission. Chikungunya virus (found in Asia and Africa), Mayaro virus (found in South America), Ross River virus (found in Australia) and Sindbis virus (found in Australia, Asia and Africa) are some examples of viruses that make up the genera Alphavirus. Rubella virus is the only viral species in the genera Rubivirus. Pestiviruses and Flaviviruses are other members of the Togaviridae family. Rubella virus which causes German measles in children is one of the most important members of this family, and this is because of the disease they cause in human population. Rubella virus is found in the genera Rubivirus.

Viruses in the Togaviridae family have an icosahedral nucleocapsid and they are generally enveloped viruses. The viruses in this family exit their host cell through the plasma or cytoplasmic membrane by budding. They have a ss(+)RNA and their replication is in the cytoplasm. They measure between 50-70 nm in diameter. The viruses in the Togaviridae family have a worldwide distribution. Chikungunya virus, and Alphavirus and rubella virus, a Rubivirus are the two viruses in the Togaviridae family that causes infection in humans. It is noteworthy that viruses in the genera Alphavirus are usually geographically limited to some regions of the world. German measles or rubella is a benign form of measles in children and young adults, and the disease is usually characterized by the appearance of maculopapular rash on the skin. Rubella used to be a worldwide epidemic but since the advent of vaccination, the disease has been significantly contained in countries where it is usually endemic.

Pregnant women especially those in their first trimester of pregnancy who are infected with rubella virus can induce serious congenital defects due to rubella virus infection in their unborn child. Rubella is a highly in factious disease and its transmission route is via the respiratory tract of humans (in respiratory droplets). Arthralgia (joint pains), fever, and maculopapular rash are some of the clinical symptoms of rubella (German measles); and there is no active treatment for the disease since most cases are self-limiting in affected individuals. Active rubella immunization still remains the basis for the effective control of rubella infection in human population. Vaccines are also available for the prevention of infection caused by Alphaviruses.

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MicroDok

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