Is picornavirus naked or enveloped?

Is picornavirus naked or enveloped?

Non-enveloped, spherical, about 30 nm in diameter, T=pseudo3 icosahedral capsid surrounding the naked RNA genome. The capsid consists of a densely-packed icosahedral arrangement of 60 protomers, each consisting of 4 polypeptides, VP1, VP2, VP3 and VP4.

How is Picornaviridae transmitted?

Epidemiology. Picornaviruses are widely prevalent. Enteroviruses are transmitted by the fecal-oral route, via salivary and respiratory droplets, and in some cases via conjunctival secretions and skin lesion exudates.

What specific diseases result from infection’s within the viral family Picornaviridae?

Infection with various picornaviruses may be asymptomatic or may cause clinical syndromes such as aseptic meningitis (the most common acute viral disease of the CNS), encephalitis, the common cold, febrile rash illnesses (hand-foot-and-mouth disease), conjunctivitis, herpangina, myositis and myocarditis, and hepatitis.

Is polio a picornavirus?

Poliomyelitis (commonly known as “polio”) is an infectious disease caused by polioviruses 1, 2, and 3 in the enterovirus genus of the picornaviridae viral family. From a public health standpoint, it is the most important of the enteroviruses.

Where do enteroviruses originate?

Enteroviruses are shed in respiratory secretions and stool and sometimes are present in the blood and cerebrospinal fluid of infected patients. Infection is usually transmitted by direct contact with respiratory secretions or stool but can be transmitted by contaminated environmental sources (eg, water).

How do enteroviruses cause meningitis?

How is enteroviral meningitis transmitted? The non-polio enteroviruses that cause meningitis are transmitted faecal-orally. The enteroviruses live in the human gastro-intestinal tract, and are shed in the faeces. Enteroviruses are very stable in the environment and can live outside human body for days.

Is polio in the Picornaviridae family?

The Picornaviridae are an important family of RNA viruses which includes the poliovirus, the coxsackievirus, and ECHOvirus.

Is Rhinovirus fecal oral?

Rhinoviruses are found in the respiratory tract. Although enteroviruses are transmitted mostly by the fecal-oral route, they can also be transmitted by salivary and respiratory droplets. Some serotypes are spread by conjunctival secretions and exudates from skin lesions.

What are the different types of picornaviridae?

Classification and Antigenic Types. The family Picornaviridae comprises five genera: Enterovirus, Hepatovirus and Rhinovirus, which infect humans: Apthovirus (foot-and-mouth disease virus), which infects cloven-hoofed animals and occasionally humans; and Cardiovirus, which infects rodents.

What is the structure of a viral capsid?

The capsid is built up of identical, non-covalently linked structural subunits, which may be discernible by electron microscopy as protrusions or depressions on the surface of virions (Fig. 3.4). These may correspond to individual viral proteins or aggregates of proteins.

What is an icosahedral capsid virus?

They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30-nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis.

What is the size of a viral particle in nm?

Depending on the type and degree of dehydration, the viral particle is around 30–32 nm in diameter. The viral genome is around 2500 nm in length, so it is tightly packaged within the capsid along with substances such as sodium ions to balance the negative charges on the RNA caused by the phosphate groups.