Bunyavirales

Order of viruses

Bunyavirales is an order of negative-sense single-stranded RNA viruses in the class Ellioviricetes. This order includes several families of viruses that are known to infect a wide range of hosts, including humans, animals, and plants. The viruses in this order are characterized by their segmented RNA genome and their ability to be transmitted by arthropod vectors such as mosquitoes and ticks.

Structure

Peribunyavirus virion structure

The virions of Bunyavirales are generally spherical and enveloped, with a diameter of approximately 80-120 nm. The viral envelope is derived from the host cell membrane and contains glycoproteins that are essential for virus attachment and entry into host cells. The genome of Bunyavirales is segmented into three parts: the large (L), medium (M), and small (S) segments, which encode the RNA-dependent RNA polymerase, glycoproteins, and nucleocapsid proteins, respectively.

Genome

The genome of Bunyavirales is composed of three segments of negative-sense RNA. The L segment encodes the RNA-dependent RNA polymerase, which is necessary for the replication of the viral RNA. The M segment encodes the glycoproteins, which are involved in virus attachment and entry into host cells. The S segment encodes the nucleocapsid protein, which encapsidates the viral RNA and is involved in the formation of the ribonucleoprotein complex.

Replication

Replication of Bunyavirales occurs in the cytoplasm of the host cell. After entry into the host cell, the viral RNA is released into the cytoplasm, where it is transcribed and replicated by the viral RNA-dependent RNA polymerase. The newly synthesized viral RNA is then packaged into new virions, which bud from the host cell membrane to be released and infect new cells.

Transmission

Bunyavirales are primarily transmitted by arthropod vectors such as mosquitoes, ticks, and sandflies. Some members of this order, such as hantaviruses, can also be transmitted through contact with infected rodent excreta. The transmission cycle typically involves the virus being maintained in a reservoir host, such as a rodent or bird, and being transmitted to humans or other animals through the bite of an infected vector.

Diseases

Bunyavirales includes several viruses that are pathogenic to humans and animals. Notable diseases caused by members of this order include Rift Valley fever, Crimean-Congo hemorrhagic fever, and Hantavirus pulmonary syndrome. These diseases can range from mild febrile illnesses to severe hemorrhagic fevers with high mortality rates.

Families

The order Bunyavirales is divided into several families, each containing multiple genera and species. Some of the notable families include:

• Arenaviridae: Includes viruses such as Lassa virus, which causes Lassa fever.
• Hantaviridae: Includes hantaviruses, which are responsible for hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome.
• Nairoviridae: Includes Crimean-Congo hemorrhagic fever virus.
• Peribunyaviridae: Includes viruses such as La Crosse virus, which causes encephalitis.

Related pages

• Virus classification
• Negative-sense single-stranded RNA virus
• Arthropod-borne virus