Question

In cases of filariasis, sample for microscopic detection of microfilariae is taken at night because

• A. Since the disease is spread by mosquitoes, it is best to take the sample at night
• B. The larvae circulate in the bloodstream of patients only at night
• C. Microfilariae circulate in the capillaries in the superficial parts of the body only during the night
• D. Microfilariae reproduce during the night so, larger number can be found in one sample

Answer 1

The correct option is C Microfilariae circulate in the capillaries in the superficial parts of the body only during the night

Wuchereria bancrofti is a filarial nematode that, as an adult, is a thread-like worm. Adult worms reside in the lymph nodes where the female parasite reproduces to form larvae. While the larvae called microfilariae circulate in the bloodstream. During daytime the microfilariae moves through the blood vessels deep inside the body and during night time it moves to the superficial parts, that is the capillaries in the skin. The standard test for detecting the infection is microscopic examination of a blood smear for presence of the microfilariae. The blood should be sampled at night because like I mentioned earlier, that is when the larvae circulate in the superficial part of the body.