What is the symmetry of pox viruses?
What is the symmetry of pox viruses?
The core contains the viral DNA, together with several proteins. There is no isometric nucleocapsid conforming to either icosahedral or helical symmetry that is found in most other viruses; hence poxviruses are said to have a “complex” structure.
How is paramyxovirus transmitted?
Transmission is by droplets or direct contact. The virus infects the ciliated epithelial cells of the respiratory mucosa and disseminates locally. Disease is caused partly by immunopathologic antibody-dependent cellular cytotoxicity.
How does smallpox virus replicate?
The exact mechanism of entry is not yet known. Upon invasion of a host cell, the smallpox virus replicates in the host cytoplasm, rather than the host nucleus, using many of the host’s own enzymes to replicate.. Replication begins once the virion has reached the cytoplasm of the host cell..
Where does pox virus replicate?
Poxviruses are large, enveloped viruses that replicate in the cytoplasm and encode proteins for DNA replication and gene expression.
What is the size of poliovirus?
The viral particle is about 30 nm in diameter with icosahedral symmetry. Because of its short genome and its simple composition—only RNA and a nonenveloped icosahedral protein coat that encapsulates it, poliovirus is widely regarded as the simplest significant virus.
Why does pox virus replicates in cytoplasm?
Poxviruses encode for more than 250 proteins, including the machinery that enables these viruses to carry out both transcription and replication in the cytoplasm (5). The com- plex life cycle of poxviruses thus occurs largely in the cytoplasm, although nuclear factors may be required for intermediate transcription (6).
Which disease is caused by paramyxovirus?
A number of important human diseases are caused by paramyxoviruses. These include mumps, as well as measles, which caused around 733,000 deaths in 2000. The human parainfluenza viruses (HPIV) are the second most common causes of respiratory tract disease in infants and children.
Is smallpox RNA or DNA?
Smallpox is a double-stranded, 135- to 375-kilobase (kb) DNA virus that replicates in the cytoplasm of the host cell and forms B-type inclusion bodies (Guarnieri bodies). This is in contrast to herpes viruses, which replicate in the nucleus. The orthopoxviruses are among the largest and most complex of all viruses.
Why does pox virus replicate in cytoplasm?
What causes pox virus?
Chickenpox infection is caused by the varicella-zoster virus. It can spread through direct contact with the rash. It can also spread when a person with the chickenpox coughs or sneezes and you inhale the air droplets.
Is COVID-19 an RNA virus?
COVID-19, short for “coronavirus disease 2019,” is caused by the novel coronavirus SARS-CoV-2. Like many other viruses, SARS-CoV-2 is an RNA virus. This means that, unlike in humans and other mammals, the genetic material for SARS-CoV-2 is encoded in ribonucleic acid (RNA).
What kind of viruses are in the Parvoviridae?
The Parvoviridae are a family of small, rugged, genetically-compact DNA viruses, known collectively as parvoviruses.
How are parvoviruses and bidnaviruses related?
Parvoviruses are believed to be descended from ssDNA viruses that have circular genomes that form a loop because these viruses encode a replication initiator protein that is related to NS1 and have a similar replication mechanism. Another group of viruses called bidnaviruses appear to be descended from parvoviruses.
When was the first parvovirus found in humans?
The first pathogenic human parvovirus to be discovered was parvovirus B19 in 1974, which became associated with various diseases throughout the 1980s. Parvoviruses were first classified as the genus Parvovirus in 1971 but were elevated to family status in 1975.
What kind of disease does parvovirus B19 cause?
Parvovirus B19 was the first pathogenic human parvovirus to be discovered and is best known for causing a childhood exanthem called ” fifth disease ” ( erythema infectiosum ), although it is also associated with other diseases including arthritis . Canine parvovirus causes a virulent and contagious disease in dogs.
