About rabies true is ?
**Core Concept**
Rabies is a viral zoonotic disease caused by the rabies virus (RABV), primarily affecting the central nervous system (CNS). It is transmitted through the saliva of infected animals, usually through bites.
**Why the Correct Answer is Right**
The rabies virus infects the CNS via peripheral nerves, specifically the dorsal root ganglia. Once inside the CNS, the virus replicates and spreads to the brainstem, causing severe inflammation and necrosis. This leads to the characteristic symptoms of rabies, including hydrophobia, aggression, and seizures. The virus ultimately results in fatal encephalitis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the primary mode of rabies transmission.
**Option B:** This option is incorrect as it does not accurately describe the pathogenesis of rabies within the CNS.
**Option C:** This option is incorrect as it does not mention the critical role of the peripheral nervous system in rabies transmission.
**Clinical Pearl / High-Yield Fact**
To diagnose rabies, a rapid fluorescent focus assay (RFFA) or a direct immunofluorescence assay (DFA) can be performed on brain tissue or saliva samples. Prompt post-exposure prophylaxis (PEP) with rabies immunoglobulin and vaccination can prevent the development of the disease.
**Correct Answer: D. The rabies virus replicates in the CNS by infecting the dorsal root ganglia.**