How does a virus infect a specific type of cell?
A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
Why do viruses only infect specific types of cells?
Viruses can infect only certain species of hosts and only certain cells within that host. The molecular basis for this specificity is that a particular surface molecule, known as the viral receptor, must be found on the host cell surface for the virus to attach.
What are the specific properties of viruses?
Viruses are the smallest infectious agents (ranging from about 20 to 300 nm in diameter) and contain only one kind of nucleic acid (RNA or DNA) as their genome. The nucleic acid is encased in a protein shell, which may be surrounded by a lipid-containing membrane. The entire infectious unit is termed a virion.
What two viruses infect all vertebrates?
Examples include, rabies, yellow fever and pappataci fever. The viruses that infect other vertebrates are related to those of humans and most families of viruses that cause human diseases are represented. They are important pathogens of livestock and cause diseases such as foot-and-mouth disease and bluetongue.
Can viruses be transmitted from animals to humans?
However, animals can sometimes carry harmful germs that can spread to people and cause illness – these are known as zoonotic diseases or zoonoses. Zoonotic diseases are caused by harmful germs like viruses, bacterial, parasites, and fungi.
What animal did Ebola come from?
Scientists do not know where Ebola virus comes from. However, based on the nature of similar viruses, they believe the virus is animal-borne, with bats or nonhuman primates (chimpanzees, apes, monkeys, etc.) being the most likely source.
Are there good viruses in our body?
Impact on human health The human virome is a part of our bodies and will not always cause harm. Many latent and asymptomatic viruses are present in the human body all the time. Viruses infect all life forms; therefore the bacterial, plant, and animal cells and material in our gut also carry viruses.