Question

Consider the following statements about rickettsial diseases:
1. These are transmitted by arthropods.
2. Eschar is not seen in Rocky Mountain spotted fever.
3. Weil-Felix reaction may be diagnostic.
4. Cephalosporins are the drug of choice.
Which of these statements are correct?

• A. 1, 2 and 3
• B. 2, 3 and 4
• C. 1, 3 and 4
• D. 1, 2 and 4

Hint:

Recall which antibiotic class, not cephalosporins, treats rickettsial infections.

Answer 1

The Correct Option is A

This question checks four facts about rickettsial diseases together, and we need to find which three of the four statements are true.

1. Statement 1, transmitted by arthropods: True. Rickettsial diseases spread through the bite of arthropod vectors such as ticks, mites, lice and fleas, for example ticks for Rocky Mountain spotted fever and lice for epidemic typhus.
2. Statement 2, eschar is not seen in Rocky Mountain spotted fever: True. Unlike some other spotted fevers such as Mediterranean spotted fever or African tick bite fever, Rocky Mountain spotted fever classically does not show an eschar (a black scab at the bite site).
3. Statement 3, Weil-Felix reaction may be diagnostic: True. This test uses cross reacting antibodies against certain Proteus strains (OX-19, OX-2, OX-K) to support the diagnosis of several rickettsial diseases, even though it is not fully specific.
4. Statement 4, cephalosporins are the drug of choice: False. The actual drug of choice for rickettsial diseases is doxycycline (a tetracycline), not a cephalosporin, since rickettsiae are obligate intracellular organisms that respond to agents like tetracyclines and chloramphenicol.

So statements 1, 2 and 3 hold up as correct, while statement 4 is wrong.

Let's summarize:

• Arthropod transmission, absence of eschar in RMSF, and a useful Weil-Felix test are all accurate.
• Doxycycline, not a cephalosporin, is the standard treatment for rickettsial infections.

So the correct combination is statements 1, 2 and 3.