Question

Sand flies play a significant role in spreading kala-azar because they

• A. Inject promastigote into the body of the non-infected person at the time of bloodsucking.
• B. Convert amastigote into promastigote.
• C. Engulf amastigote at the time of blood sucking from the infected person.
• D. All of the above.

Answer 1

Answer: (D)

All of the above.

Kala-azar (black fever) is a disease caused by protozoa Leishmania. Sandfly of genus Phlebotomus argentipes is the vector (transmitter) of kala-azar. Leishmania requires two hosts, sandfly and human to complete its life cycle. The protozoan exists in two forms, amastigote and promastigote. When sandfly bites the person infected with kala-azar, amastigote along with blood is ingested. After ingestion, amastigote converts into active form that is promastigote. Thus, when sandfly bites the non-infected person, it transfers promastigote into the non-infected person.

Thus, the correct answer is option D.