Which is correct about influenza?
Multiple Choice
A The virus binds to the intestinal mucosa.
B The virus is grown in poultry eggs for vaccines.
C The virus is found in swine and cats.
D Antigenic shift is a minor change in the viral strain.
The correct answer and explanation is:
The correct answer is B: The virus is grown in poultry eggs for vaccines.
Influenza viruses are typically grown in embryonated chicken eggs, which are used to produce the majority of flu vaccines. This method has been a standard practice for decades because the virus grows efficiently in the eggs, and the harvested virus can then be inactivated or attenuated to make vaccines. This process is both cost-effective and widely available, making it a reliable option for producing vaccines on a large scale.
Here’s why the other options are incorrect:
- A: The virus binds to the intestinal mucosa.
Influenza primarily affects the respiratory system, particularly the upper and lower airways. The virus binds to the respiratory mucosa, not the intestinal mucosa. It attaches to receptors on the surface of cells in the respiratory tract using the hemagglutinin protein. - C: The virus is found in swine and cats.
While influenza viruses can infect a variety of animals, including pigs (swine) and, rarely, cats, they are not the primary reservoirs. Birds, particularly wild waterfowl, are the main natural hosts for influenza A viruses. Swine can act as intermediaries for the mixing of different viral strains, which can lead to new subtypes, but they are not the primary source for human infections. - D: Antigenic shift is a minor change in the viral strain.
Antigenic shift refers to a major change in the influenza virus, often involving reassortment of genetic material from different viral strains. This results in a new subtype of the virus to which the human population may have little to no immunity, leading to potential pandemics. A “minor change” would describe antigenic drift, which involves smaller mutations over time.
In summary, growing influenza in poultry eggs for vaccines is a well-established practice, while the other statements are either inaccurate or incomplete in describing the virus.