Modoc virus

A virus of the family Flaviviridae

The Modoc virus (MODV) is a member of the Flavivirus genus within the Flaviviridae family. It is an arbovirus, which means it is transmitted by arthropods, although its specific vector is not well-defined. The virus was first isolated in 1958 from a deer mouse in Modoc County, California, USA.

Virology

Image reconstructions from cryo-electron micrographs of flavivirus

The Modoc virus is a small, enveloped virus with a single-stranded, positive-sense RNA genome. The genome is approximately 11,000 nucleotides in length and encodes a single polyprotein that is processed into structural and non-structural proteins. The structural proteins include the capsid (C), membrane (M), and envelope (E) proteins, which are critical for virus entry and assembly.

Genome

Genomic RNA of Flavivirus

The genome of the Modoc virus is organized similarly to other flaviviruses, with a 5' untranslated region (UTR), a single open reading frame (ORF), and a 3' UTR. The ORF encodes a polyprotein that is cleaved by viral and host proteases into three structural proteins (C, prM, E) and seven non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5).

Transmission and Hosts

Deer mouse, a potential host for Modoc virus

The primary host of the Modoc virus is believed to be the deer mouse (Peromyscus maniculatus), although other small mammals may also serve as reservoirs. The exact mode of transmission is not well understood, but it is presumed to occur through contact with infected rodents or their excreta. Unlike many other flaviviruses, Modoc virus is not known to be transmitted by mosquitoes or ticks.

Pathogenesis

The Modoc virus is not known to cause disease in humans, and infections are typically asymptomatic. However, it can cause disease in laboratory animals, where it has been shown to infect the central nervous system and other tissues.

Modoc virus in tissues

In experimental settings, the virus has been shown to replicate in various tissues, including the brain, liver, and spleen. The pathogenesis of Modoc virus in natural hosts remains poorly understood.

Replication Cycle

Virus entry, replication, and assembly

The replication cycle of the Modoc virus follows the typical pattern of flaviviruses. The virus enters host cells through receptor-mediated endocytosis, followed by fusion of the viral envelope with the endosomal membrane. The viral RNA is released into the cytoplasm, where it is translated into a polyprotein. The polyprotein is cleaved into individual proteins that participate in viral replication and assembly. New virions are assembled in the endoplasmic reticulum and are released from the cell by exocytosis.

Related pages

• Flavivirus
• Flaviviridae
• Arbovirus
• Deer mouse