Which of the following statements about rabies is true?
**Core Concept**
Rabies is a viral zoonotic disease caused by the rabies virus (RABV), primarily transmitted through the saliva of infected animals, typically through bites. The virus targets the central nervous system (CNS) and is characterized by a fatal outcome if left untreated.
**Why the Correct Answer is Right**
The correct answer is related to the pathogenesis of rabies. After entering the body through a bite wound, the virus travels to the CNS via peripheral nerves, where it replicates and causes inflammation of the brain and spinal cord. This leads to the characteristic symptoms of rabies, including hydrophobia, aggression, and eventually, coma and death.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as rabies is not primarily spread through respiratory droplets. While the virus can be present in the saliva, transmission through respiratory droplets is rare.
**Option B:** Incorrect, as the rabies virus is not highly sensitive to environmental factors such as temperature and humidity. It remains viable in the environment for extended periods.
**Option C:** Incorrect, as the incubation period of rabies can range from a few days to several years, with an average of 2-3 months.
**Clinical Pearl / High-Yield Fact**
Prolonged exposure to the virus, such as in cases of licks or scratches, does not necessarily lead to rabies transmission, as the virus requires a direct bite or mucous membrane exposure to establish infection.
**Correct Answer:** D.