This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Prepatent period&; in lymphatic filariasis is defined as the time interval between inoculation of infective larvae and - 
Select and explain. 
A. Blockage of lymphatics, B. First appearance of detectable microfilaria, C. Development of lymphoedema, D. Development of adult worm
B: First appearance of detectable microfilaria
Answer: B: First appearance of detectable microfilaria 
Explanation: <p> lymphatic filariasis:- Pre patent period-Time interval between inoculation of infective larvae and first appearance of detectable microfilaria. Clinical incubation period-Time interval from invasion of infective larva to development of clinical manifestation. 8-16 months. {Reference: park&;s textbook of preventive and social medicine, 23rd edition, pg no.272}</p>