Answer: Virus
A pathogen is an agent which causes infections and disease oriented symptoms in living organisms like plants, animals, humans and others. Examples of pathogens are bacteria, virus, protozoa and others. Measle is virus, which causes disease characterized by it's own name called as measles. Measles is an airborne disease. It spreads from the infectious person to healthy person through cough, nasal secretions and contact with saliva. The symptoms remain for 10-12 days. Symptoms initiates with fever, than cough, runny nose and inflamed eyes. Small spots develop, later develop into red rashes all over the body. Diarrhea, pneumonia and middle ear infection are also common. Other severe symptoms includes blindness and inflammation of brain. Measle vaccines are highly preventive measure against measles.