Which of the following is a reservoir for measles
**Core Concept**
Measles is a highly contagious viral infection caused by the measles virus, a paramyxovirus. The virus can survive outside the host for a short period but primarily relies on human hosts for survival and transmission.
**Why the Correct Answer is Right**
The correct reservoir for measles is humans. Measles virus replicates in the respiratory tract and spreads through respiratory droplets, close contact, and contaminated surfaces. The virus can also survive in the respiratory secretions of an infected person for up to 2 hours. The measles virus has a high basic reproduction number (R0), which is approximately 12-18, indicating its high contagiousness among humans.
**Why Each Wrong Option is Incorrect**
**Option A:** There is no scientific evidence to support animals as a reservoir for measles virus. While animals can be infected with various paramyxoviruses, they are not considered a reservoir for measles.
**Option B:** Measles vaccine is highly effective in preventing measles infection but does not serve as a reservoir for the virus.
**Option C:** Measles virus is not known to have a natural reservoir in the environment. It primarily relies on human hosts for survival and transmission.
**Clinical Pearl / High-Yield Fact**
Measles is a vaccine-preventable disease, and vaccination is crucial in controlling outbreaks. According to the World Health Organization (WHO), measles vaccination has led to a 84% reduction in measles deaths globally since 2000.
**Correct Answer:** D. Humans