Virology

PARAMYXOVIRIDAE FAMILY

Written by MicroDok

Paramyxoviridae family is a large family of viruses that infect both humans and animals. Viruses in this family are generally called paramyxoviruses; and they include the most important causative agents of respiratory infections in young children and infants (i.e. respiratory synctial virus and parainfluenza viruses) as well as the causative agent of measles – a highly infectious viral disease of global health importance that have been eradicated. Paramyxoviruses have a ss(-)RNA genome; and they are enveloped viruses. They have a helical nucleocapsid and paramyxoviruses measure between 150-350 nm in diameter. Paramyxoviruses replicate in the cytoplasm of their host cell and they are released by a budding process through the cytoplasmic membrane.

The Paramyxoviridae family is divided into two subfamilies viz: Paramyxovirinae and Pneumovirinae. Paramyxovirinae subfamily is comprised of five genera: Respirovirus (which contain the human parainfluenza viruses – types 1 and 3), Rubulavirus (which contain mumps virus and the human parainfluenza viruses – types 2 and 4), Avulavirus (which contain Newcastle disease and avian parainfluenza viruses), Morbillivirus (which contain measles virus) and Henipavirus (which contain Hendra and Nipah viruses). The Pneumovirinae subfamily contains only two genera: Pneumovirus (which contain the human respiratory synctial virus) and Metapneumovirus (which contain viruses that infect birds such as turkey). Paramyxoviruses have a worldwide distribution with the exception of viruses in the genera Henipavirus – which are geographically limited and are found in parts of Asia including Malaysia, Singapore and Australia.

Majority of the diseases caused by paramyxoviruses including mumps, parainfluenza and measles are known as notifiable diseases that must be reported to public health authorities for proper action to be taken to contain their outbreak and spread. Paramyxoviruses are mainly spread via aerosols and the respiratory tract as droplet infections; and they majorly affect children and infants inclusive of adults. Attenuated live vaccines exist for the prevention of mumps and measles in children and other susceptible human population. And antiviral agents are also available for the treatment of infections caused by paramyxoviruses. Due to the high morbidity and mortality associated with paramyxoviruses infection especially measles (a childhood disease characterized by the appearance of maculopapular rash all over the body); infections caused by paramyxoviruses still remain amongst the preventable diseases that newborns and susceptible populations are vaccinated against all over the world.             

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