## **Core Concept**
Soft ticks, also known as Argasidae, are vectors for certain diseases. Unlike hard ticks, which are known for transmitting diseases like Lyme disease, soft ticks transmit different types of illnesses. The question focuses on identifying a disease specifically transmitted by soft ticks.

## **Why the Correct Answer is Right**
The correct answer, **C.**, refers to **Relapsing Fever**. This disease is caused by bacteria of the genus *Borrelia* and is transmitted to humans through the bite of infected soft ticks (*Argas* species). Relapsing fever is characterized by recurring episodes of fever and can lead to serious complications if left untreated. The bacteria evade the immune system by changing their surface antigens, leading to the relapsing nature of the disease.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not correspond to a disease known to be transmitted by soft ticks.
- **Option B:** This option is incorrect as it refers to a different condition or disease not associated with soft tick transmission.
- **Option D:** This option is incorrect because it represents another disease or condition not transmitted by soft ticks.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that soft ticks are often associated with **relapsing fever** and **tick-borne** **rickettsial** **diseases** like **Rickettsia** *africae* (though the latter is more commonly associated with hard ticks). However, the classic association with soft ticks is relapsing fever. A helpful mnemonic or fact is that soft ticks can transmit diseases that cause recurring symptoms, such as the fever in relapsing fever.

## **Correct Answer: C. Relapsing Fever**