A living microbe with reduced virulence that is used for vaccination is considered:
a. A toxoid
b. Dormant
c. Virulent
d. Attenuated
e. Denatured
The correct answer and explanation is :
The correct answer is d. Attenuated.
Explanation:
In the context of vaccination, an attenuated microbe refers to a living microorganism (bacterium, virus, etc.) that has been modified to reduce its ability to cause disease. This process is known as “attenuation,” and it involves weakening the pathogen so that it cannot cause severe disease in healthy individuals but still triggers a robust immune response. Attenuated vaccines are typically made by growing the microorganism in unnatural conditions or through genetic modifications that reduce its virulence (disease-causing ability).
The use of attenuated microbes in vaccines is based on the principle that the body will recognize and respond to the weakened pathogen as if it were a fully virulent form. The immune system will then “learn” to recognize the pathogen and remember it for future encounters, without causing the disease associated with the original pathogen. This memory is crucial for providing immunity, meaning that if the person is later exposed to the full-strength pathogen, their immune system can fight it off more effectively.
Examples of attenuated vaccines include:
- Measles, mumps, and rubella (MMR) vaccine
- Oral polio vaccine (OPV)
- Yellow fever vaccine
Other Options Explained:
- a. A toxoid: A toxoid is a toxin that has been inactivated or modified (typically through heat or chemical treatment) to be non-toxic but still capable of stimulating an immune response. Toxoids are used to vaccinate against diseases caused by bacterial toxins (e.g., tetanus and diphtheria).
- b. Dormant: Dormant refers to a state where a microorganism is inactive, but it is not used specifically for vaccines. While some microbes can remain dormant, the term doesn’t describe a reduced-virulence organism used for immunization.
- c. Virulent: A virulent microbe is one that is capable of causing disease in its full-strength form. Virulent organisms are typically not used in vaccines due to their ability to cause harmful diseases.
- e. Denatured: Denaturation refers to the alteration of a protein’s structure, usually making it inactive. It can be a process in preparing vaccines, but it does not apply to the concept of living, weakened organisms used in vaccination.
Thus, attenuated is the best choice when referring to a live microbe used in vaccination with reduced virulence.