Polivirales

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Polivirales
Kingdom:	Orthornavirae
Phylum:	Pisuviricota
Class:	Pisoniviricetes
Order:	Polivirales
Family:	'

Polivirales is an order of viruses within the class Pisoniviricetes, phylum Pisuviricota, and realm Riboviria. This order includes viruses that are characterized by their positive-sense single-stranded RNA genomes. The order Polivirales is known for containing viruses that infect a wide range of hosts, including humans, animals, and plants.

Characteristics

Viruses in the order Polivirales have a non-enveloped, icosahedral capsid structure. Their genomes are typically linear, positive-sense single-stranded RNA, which allows them to be directly translated by the host's ribosomes upon infection. The genome size can vary significantly among different families within the order, but it generally ranges from 7 to 12 kilobases.

The replication cycle of Polivirales viruses involves the synthesis of a polyprotein that is subsequently cleaved into functional viral proteins. This strategy is common among positive-sense RNA viruses and allows for efficient use of the viral genome.

Families

The order Polivirales comprises several families, the most notable of which are:

• Picornaviridae: This family includes important human pathogens such as Enterovirus (which includes Poliovirus and Coxsackievirus), Hepatovirus (which includes Hepatitis A virus), and Rhinovirus (which causes the common cold).

• Secoviridae: This family primarily includes plant viruses, such as Tomato ringspot virus and Grapevine fanleaf virus. These viruses are significant in agriculture due to their impact on crop health and yield.

Pathogenesis

Viruses within the Polivirales order can cause a variety of diseases depending on the host and the specific virus. For example, members of the Picornaviridae family can cause diseases ranging from mild respiratory infections to severe neurological diseases like poliomyelitis. Plant viruses in the Secoviridae family can lead to significant agricultural losses by affecting plant growth and productivity.

Transmission

Transmission of Polivirales viruses varies by family and host. Human and animal viruses are often transmitted via the fecal-oral route, respiratory droplets, or direct contact. Plant viruses are typically spread through vectors such as insects or through mechanical means during agricultural practices.

Research and Importance

Research on Polivirales is crucial for understanding viral evolution, pathogenesis, and for developing vaccines and antiviral therapies. The study of these viruses has led to significant advancements in molecular biology, including the development of the polio vaccine and insights into RNA virus replication.

Also see

• Positive-sense single-stranded RNA virus
• Virus classification
• Viral replication
• Picornavirus
• Plant virus