Measles is a highly contagious and serious airborne disease caused by a virus that can lead to severe complications and death. The infection can cause symptoms such as high fever, cough, runny nose, and a red rash all over the body. Complications may include ear infections, pneumonia, diarrhea, and swelling of the brain. Measles can be particularly dangerous for pregnant women, infants, and people with compromised immune systems. The best way to prevent measles and its potentially devastating consequences is through vaccination. 

The three signs or symptoms of measles are:

1. High Fever: 

Measles is typically accompanied by a high fever, which can spike to more than 104°F.

2. Cough: 

A persistent cough is a common symptom of measles.

3. Runny Nose: 

Measles can cause a runny or blocked nose, along with other cold-like symptoms.

In addition to these three primary symptoms, other common signs and symptoms of measles include inflamed eyes (conjunctivitis), tiny white spots with bluish-white centers on a red background found inside the mouth (Koplik spots), and a red rash that usually appears a few days after the initial symptoms

Measles in adults typically begins with symptoms such as high fever, cough, runny nose, and watery eyes. After 2-3 days, tiny white spots called Koplik spots may appear inside the mouth, followed by a red or reddish-brown rash 3-5 days after the first symptoms, starting on the face and spreading downward to the trunk, arms, legs, and feet. The rash consists of flat red spots that may join together and be accompanied by small raised bumps. The fever may spike to more than 104°F when the rash appears. The infection occurs in stages over 2 to 3 weeks, with the rash lasting about seven to 10 days. The measles rash is red or reddish-brown in color and starts on the face, working its way down the body over a few days: from the neck to the trunk, arms, and legs, until it finally reaches the feet.

Chickenpox and measles are caused by two different viruses and have distinct symptoms. Here are the main differences between the two:

Chickenpox is caused by the Varicella-zoster virus. The symptoms include: Rash that starts on the chest, face, and back and spreads to the rest of the body. Fever, headache, tiredness, decreased appetite. The duration is typically infection lasting about 5 to 10 days.

Measles is caused by the measles virus. The symptoms include: Rash that starts at the hairline of forehead and spreads downward. High fever, hacking cough, runny nose. The duration is usually longer than chickenpox, typically 7 to 10 days for the rash.

Both diseases are highly contagious but can be prevented through vaccination. It’s important to consult a healthcare professional for an accurate diagnosis and appropriate treatment.