Enterovirus E
A picornavirus endemic in cattle, causing disease under coinfection.
Enterovirus E, once called bovine enterovirus (BEV) and also known as enteric cytopathic bovine orphan virus (ECBO), belongs to the picornavirus family within the Enterovirus genus. This virus is widespread in cattle herds around the world. Although it usually causes little to no illness, it can lead to problems with reproduction, breathing, or digestion—especially if the animal is also infected with another germ. There is no evidence that the virus spreads from animals to humans.
The virus spreads horizontally through either the oral-fecal route or via respiratory droplets. Infected animals may shed the virus for several months after first becoming infected.
Like other picornaviruses, BEV has a capsid made of 60 copies each of four structural proteins—VP1, VP2, VP3, and VP4—arranged in an icosahedral shape. The capsid is about 27 nanometers across, lacks an envelope, and is roughly spherical, with an outer radius of 159 angstroms and an inner radius of 107 angstroms. It encloses a single-stranded, positive-sense RNA genome roughly 7,500 bases long. The outer surface of BEV is smoother than that of the closely related poliovirus because its surface protein loops are shorter. Compared to human rhinovirus, BEV is smoother due to an extended surface loop. The virus’s three antigenic sites sit on a ridge where VP1, VP2, and VP3 meet. At the fivefold axis of the icosahedron, BEV has a crater-like depression leading into a cylindrical hole 10 angstroms wide that runs nearly to the inner capsid surface. Inside VP1, a hydrophobic pocket holds a myristic acid molecule; removing this molecule appears necessary for the virus to uncoat.
To replicate, BEV must attach to a host cell surface receptor, enter the cell’s cytoplasm, and uncoat its genome. The exact receptor is unknown, but it is sensitive to the enzyme neuraminidase.
Originally, BEVs were grouped into seven serotypes, but they are now recognized as falling into just two serotypes—1 and 2—which are further divided into subtypes. The most studied strain is VG-5-27, a serotype 1, subtype 1 virus. Serotype 1 has a very broad tissue tropism, infecting cells from humans, sheep, horses, dogs, camels, and other mammals. BEV-like sequences have even turned up in shellfish from water contaminated with cow manure. Serotype 2 viruses infect only domestic cattle.
Most infected cattle show no symptoms. However, infecti
- field
- Virology
- known_for
- Causing reproductive, respiratory, or enteric disease in cattle; investigated for antitumor capabilities in breast cancer cell lines
- type
- Virus
- genus
- Enterovirus
- host
- Cattle (serotype 1 also infects human, sheep, horse, dog, camel, and other mammalian hosts)
Lore & Background
Enterovirus E is a non-enveloped, icosahedral virus with a capsid composed of 60 copies each of four structural proteins (VP1, VP2, VP3, VP4) and a single-stranded positive-sense RNA genome of about 7,500 bases. Its outer surface is smoother than poliovirus due to truncation of surface protein loops, and smoother than human rhinovirus due to extension of a surface loop. The three antigenic sites occur on a surface ridge at the junction of VP1, VP2, and VP3, and a crater-like depression at the 5-fold axis descends into a cylindrical hole. Myristic acid is attached to the N-terminus of VP4, not located in a hydrophobic pocket of VP1; its removal appears necessary for uncoating.
Reader's Guide
Enterovirus E is significant as a ubiquitous pathogen of cattle worldwide, capable of causing abortion, stillbirth, infertility, neonatal mortality, diarrhea, weight loss, and mucoid nasal discharge, though most infections are asymptomatic. Its broad tissue tropism—serotype 1 infects many mammalian hosts, including humans in vitro—and its presence in shellfish from contaminated water highlight its environmental persistence. The virus is spread horizontally via oral-fecal or respiratory routes, with shedding lasting months. Diagnosis requires ruling out other causes due to nonspecific signs; electron microscopy, PCR, and serological tests are used. Treatment is symptomatic, with isolation and hygiene measures during outbreaks. Research has explored its antitumor potential, as it replicates in breast cancer cell lines and causes cytopathic effects in human monocytes. Its smooth capsid structure and uncoating mechanism offer insights into picornavirus biology.
Did You Know?
- Enterovirus E is also called enteric cytopathic bovine orphan virus (ECBO).
- The virus has not been shown to transmit from animals to humans.
- BEV-like sequences have been reported in shellfish from water contaminated with bovine feces.
- The virus has been investigated for antitumor capabilities, replicating in breast cancer cell lines and producing a cytopathic effect in human monocytes.
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