Measles is said to be infectious
**Core Concept**
Measles is a highly contagious viral infection caused by the measles virus, primarily affecting the respiratory system. The virus is transmitted through respiratory droplets, contact with infected secretions, and airborne transmission, making it highly infectious.
**Why the Correct Answer is Right**
The measles virus is highly contagious due to its ability to survive on surfaces for up to 2 hours and its high replication rate in the respiratory tract. The virus multiplies in the epithelial cells of the respiratory tract, leading to the release of large amounts of viral particles into the air, making it highly infectious. This is further exacerbated by the fact that the measles virus can survive on surfaces and in the air for an extended period, increasing the risk of transmission.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as measles is not typically transmitted through the fecal-oral route, which is more common with gastrointestinal pathogens.
**Option B:** This option is incorrect as measles is not primarily a zoonotic disease, meaning it is not transmitted from animals to humans.
**Option C:** This option is incorrect as measles is not typically considered a vector-borne disease, meaning it is not transmitted through the bite of an infected arthropod.
**Clinical Pearl / High-Yield Fact**
It's essential to note that measles is highly infectious from 4 days before to 4 days after the onset of the rash, making it crucial to implement infection control measures during this period.
**Correct Answer: D.**