Trombiculid mite is the vector of:-
**Core Concept**
Trombiculid mites are a group of small arachnids that feed on the blood of vertebrates. They are known to transmit various diseases, including scrub typhus, which is a significant public health concern in certain regions.
**Why the Correct Answer is Right**
The correct answer is related to scrub typhus, a disease caused by the bacterium Orientia tsutsugamushi. Trombiculid mites, specifically the larvae, are the primary vectors of this disease. When an infected mite bites a human, it injects the bacteria into the skin, leading to the development of scrub typhus. The pathogenesis of scrub typhus involves the bacterium's ability to evade the host's immune system and replicate within cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the vector of Kala-azar (visceral leishmaniasis) is the sandfly (Phlebotomus spp.), not the trombiculid mite.
**Option B:** This option is incorrect because the vector of Plague is the fleas (Xenopsylla cheopis) that infest rodents, not the trombiculid mite.
**Option C:** This option is incorrect because the vector of Chikungunya is the Aedes mosquito (Aedes aegypti and Aedes albopictus), not the trombiculid mite.
**Clinical Pearl / High-Yield Fact**
Trombiculid mites are also known as "chiggers," and their bites can cause intense pruritus and localized skin reactions. However, the primary concern with trombiculid mites is their role in transmitting scrub typhus, which can lead to severe complications if left untreated.
**Correct Answer:** C. Scrub typhus