What is the process of antigenic drift?

One way flu viruses change is called “antigenic drift.” Drift consists of small changes (or mutations) in the genes of influenza viruses that can lead to changes in the surface proteins of the virus, HA (hemagglutinin) and NA (neuraminidase).

Is antigenic drift the same as genetic drift?

Antigenic drift should not be confused with antigenic shift, which refers to reassortment of the virus’ gene segments. As well, it is different from random genetic drift, which is an important mechanism in population genetics.

Where does antigenic drift occur?

Antigenic drift is a natural process whereby mutations (mistakes) occur during replication in the genes encoding antigens that produce alterations in the way they appear to the immune system (antigenic changes) (Figure 1).

What is antigenic drift How is it different than antigenic shift?

Antigenic drift vs. shift. Antigenic drift creates influenza viruses with slightly modified antigens, while antigenic shift generates viruses with entirely new antigens (shown in red).

What does hemagglutinin and neuraminidase do?

Hemagglutinin-neuraminidase (HN) protein, which is responsible for virus attachment, interacts with the fusion protein in a virus type-specific manner to induce efficient membrane fusion.

Does antigenic shift occur in rotaviruses?

Aside from showing different G and P types and an extensive variety of combinations therein, rotaviruses can accumulate point mutations leading to antigenic drift, reassortment of genome segments to drive antigenic shift, and zoonotic transmission of animal strains to introduce new antigenic types into humans.

Which protein is responsible for antigenic drift in influenza?

Antigenic drift: A subtle change in the surface glycoprotein (either hemagglutinin or neuraminidase) caused by a point mutation or deletion in the viral gene. This results in a new strain that requires yearly reformulation of the seasonal influenza vaccine.

What is antigenic drift antigenic shift during which of these events does a major pandemic occur?

Antigenic shift is a more major change in the influenza virus. This shift typically occurs when a human flu virus crosses with a flu virus that usually affects animals (such as birds or pigs). When the viruses mutate, they shift to create a new subtype that is different from any seen in humans before.

Which type of mutation occur of antigenic drift?

20 Antigenic drift is caused by point mutations in the HA and NA genes that are driven by immune pressure and the infidelity inherent in the replication of RNA genomes.

How does antigenic shift cause pandemics?

Viruses arising as a result of antigenic shift may cause pandemics, since they appear suddenly in populations that may have no immunity and against which no existing vaccine may confer protection.

What type of inhibitor is Relenza?

Relenza is the trade name of the drug that contains zanamivir, which is a neuraminidase inhibitor and antiviral drug used in the treatment and prevention of influenza.

What does drift“antigenic mean?

How the Flu Virus Can Change: “Drift” and “Shift”. The other type of change is called “antigenic shift.” Antigenic shift is an abrupt, major change in the influenza A viruses, resulting in new hemagglutinin and/or new hemagglutinin and neuraminidase proteins in influenza viruses that infect humans.

What is antigenic shift?

Antigenic shift is a major antigenic change that occurs when an influenza A virus that bears a novel HA (or novel HA and NA) antigenically distinct from that of previously circulating influenza A viruses appears in the human population. Antigenic shift is a rare event that is responsible for worldwide epidemics or pandemics.

How does antigenic drift affect the phylogeny of viruses?

The small changes that occur from antigenic drift usually produce viruses that are closely related to one another, which can be illustrated by their location close together on a phylogenetic tree. Influenza viruses that are closely related to each other usually have similar antigenic properties.

What are the two types of antigenic variation?

They are known to have two distinct types of antigenic variation: antigenic drift and antigenic shift (Roberts, 2008). The “antigenic drift” variations constantly cause minor and progressive changes in the structure of the HA and NA proteins of the influenza virus strains.

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