Which is not transmitted by arthropod :
**Core Concept**
The transmission of diseases by arthropods, such as mosquitoes, ticks, and fleas, is a significant public health concern. Arthropods can transmit a variety of pathogens, including bacteria, viruses, and parasites, through their saliva, feces, or biting behavior.
**Why the Correct Answer is Right**
Diseases transmitted by arthropods include malaria (caused by Plasmodium spp.), dengue fever (caused by dengue virus), and Lyme disease (caused by Borrelia burgdorferi). These pathogens are typically acquired through the bite of an infected arthropod. However, some diseases are not transmitted by arthropods, such as tetanus, which is caused by the bacterium Clostridium tetani and is typically acquired through cuts or wounds contaminated with soil or feces.
**Why Each Wrong Option is Incorrect**
**Option A:** Malaria is a classic example of a disease transmitted by arthropods (mosquitoes).
**Option B:** Lyme disease is also transmitted by arthropods (ticks).
**Option C:** The correct answer is not listed among the options, but diseases like tetanus are not transmitted by arthropods.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that not all diseases are transmitted by arthropods, and some have specific modes of transmission, such as tetanus, which is acquired through skin contact with contaminated soil or feces.
**Correct Answer:** D.