Parainfluenza type 3 free#

This has led to the 'rule of six' being coined.

With the advent of reverse genetics, it has been found that the most efficient human parainfluenza viruses (in terms of replication and transcription) have a genome nucleotide total that is divisible by the number 6. The structural gene sequence of HPIVs is as follows: 3′-NP-P-M-F-HN-L-5′ (the protein prefixes and further details are outlined in the table below). HPIV genomes are about 15,000 nucleotides in length and encode six key structural proteins. Non-infectious virions have also been reported to contain RNA with positive polarity. HPIVs are characterised by producing enveloped virions and containing single stranded negative sense RNA. HPIVs belong to two genera: Respirovirus (HPIV-1 & HPIV-3) and Rubulavirus (HPIV-2 & HPIV-4). These include:Ĭauses croup and other upper and lower respiratory tract illnessesĪssociated with bronchiolitis and pneumonia The taxonomic division is broadly based on antigenic and genetic characteristics, forming four major serotypes or clades, which today are considered distinct viruses.

The first HPIV was discovered in the late 1950s. Virions are approximately 150–250 nm in size and contain negative sense RNA with a genome encompassing about 15,000 nucleotides. These viruses are closely associated with both human and veterinary disease. HPIVs are a paraphyletic group of four distinct single-stranded RNA viruses belonging to the Paramyxoviridae family. Human parainfluenza viruses ( HPIVs) are the viruses that cause human parainfluenza. Human rubulavirus 4 (formerly Human parainfluenza virus 4) Ĭladistically included but traditionally excluded taxa.Human rubulavirus 2 (formerly Human parainfluenza virus 2).Human respirovirus 3 (formerly Human parainfluenza virus 3).Human respirovirus 1 (formerly Human parainfluenza virus 1).

Parainfluenza type 3 free#

Two intact particles and free filamentous nucleocapsid Transmission electron micrograph of a parainfluenza virus.