Is antigenic shift and antigenic drift same?

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).

Is antigenic shift the same as reassortment?

Antigenic shift involves major changes in proteins, sometimes through the swapping of entire gene segments. The genetic reassortment occurs when two or more unique viruses infect the same cell and generate mixed progeny viruses (Chen and Deng, 2009; Kaye and Pringle, 2005).

What is antigenic drift or genetic drift?

Antigenic drift, random genetic mutation of an infectious agent resulting in minor changes in proteins called antigens, which stimulate the production of antibodies by the immune systems of humans and animals. These mutations typically produce antigens to which only part of a population may be immune.

What is the description of antigenic drift and antigenic shift?

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).

Why is antigenic drift a problem for the immune system?

When antigenic drift occurs, the body’s immune system may not recognize and prevent sickness caused by the newer influenza viruses.

Where can you observe antigenic shift and antigenic drift?

Antigenic drift occurs in all types of influenza including influenza A, influenza B and influenza C. Antigenic shift, however, occurs only in influenza A because it infects more than just humans.

What viruses have antigenic drift?

Antigenic drift occurs in both influenza A and influenza B viruses. (Confusion can arise with two very similar terms, antigenic shift and genetic drift. Antigenic shift is a closely related process; it refers to more dramatic changes in the virus’s surface proteins.

What is an example of an antigenic shift?

An example of a pandemic resulting from antigenic shift was the 1918-19 outbreak of Spanish Influenza. This strain was originally the H1N1 avian flu, however antigenic shift allowed the viral infection to jump from pigs to humans, resulting in a large pandemic which killed over 40 million people.

What viruses go through antigenic drift?

What causes antigenic drift?

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 virus can undergo antigenic drift?

For more information, see pandemic flu. Type A viruses undergo both antigenic drift and shift and are the only influenza viruses known to cause pandemics, while influenza type B viruses change only by the more gradual process of antigenic drift.

What year was the worst pandemic in history?

The H1N1 influenza A pandemic of 1918–1920 (colloquially, but likely inaccurately, known as the Spanish flu) remains the deadliest pandemic of the modern age, with estimates of mortality ranging from 17 million to 100 million from an estimated 500 million infections globally (approximately a third of the global …

What are the differences between antigenic shift and antigenic drift?

Differences Between Antigenic Shift and Antigenic Drift. Influenza Virus are remarkable because of the frequent antigenic change that occurs in HA (hemagglutinin) or NA (neuraminidase). The two surface antigens of influenza undergo antigenic variation independent of each other. They are Antigenic Shift and Antigenic Drift.

How does antigenic drift affect the influenza virus?

In essence, drift affects the influenza viruses that are already in worldwide circulation. This process allows influenza viruses to change and re-infect people repeatedly through their lifetime and is the reason the influenza virus strains in vaccine must be updated each year. Antigenic ‘shift’ occurs in HA and NA and is associated with pandemics.

How are hemagglutinin and neuraminidase involved in antigenic drift?

The hemagglutinin is responsible for binding and entry into host epithelial cells while the neuraminidase is involved in the process of new virions budding out of host cells. Sites recognized on the hemagglutinin and neuraminidase proteins by host immune systems are under constant selective pressure.

When does an antigenic change occur what happens?

Occurs as a result of the accumulation of point mutations in the gene. An antigenic change which results in drastic or dramatic alternation in HA (hemagglutinin) or NA (neuraminidase) subtypes. An antigenic change can alter antigenic sites on the molecule such that a virion can escape recognition by the host’s immune system.