Question

Schick test is used for the diagnosis of ……………………………………infection.
A. Bordetella pertussis
B. Chlamydia trachomatis
C. Diplococcus pneumoniae
D. Corynebacterium diphtheriae

Answer 1

Hint: Several microorganisms such as bacteria, fungi, protozoans and viruses are harmful to humans and animals as they are responsible for pathogenesis of different types of diseases. Some of these microorganisms are not visible through naked eyes and they are identified by some specific tests.

Complete answer:
Microbes or microorganism are known to produce diseases both common and severe types, in humans. The infection of the microbes is diagnosed by a number of different types of test which are usually very specific in their identification.
The Schick test was developed as a skin test that is used in the determination of the susceptible nature of the body towards the infection of diphtheria. Diphtheria is an infection caused by Corynebacterium diphtheriae, a type of bacterium. The disease is characterized by symptoms such as fevers, sore throat, coughing with a barking noise, swollen and enlarged lymph nodes.
The procedure of the Schick test involves injection of a diphtheria toxin into the person to be tested along with a heat inactivated toxin. The inactivated toxin is used as a control. The important principle of the test is that if a person testing for this test does not have enough antibodies to fight it off, the area of the skin around the injected part will appear swollen which will be read as a positive test. In the opposite case, the person with enough antibodies and good immunity will show little or no swellings and redness. This is read as a negative result test.
A pseudo-positive appears when there is only a red-colored inflammation which disappears within a period of four days. The inflammation occurs in both the arms and it takes place due to the reason that the person is immune as well as hypersensitive to the toxin administered. In another case, a combined reaction is also observed as the signs are the same as pseudo reactions but occurs only in the control arm. The person is diagnosed as both immune as well as hypersensitive.

Therefore, the correct option is option D.

Note: The test employed for the diagnosis as well as determination of susceptible nature of the Corynebacterium diphtheriae, bacterium which causes the disease diphtheria is known as the Schick test. In this process, a diphtheria toxin and an inactivated toxin is administered intradermally and results are established on the basis of the immune reactions such as swelling and redness.