Description: | Caption: This transmission electron microscopic (TEM) image revealed the ultrastructural appearance of a measles virus particle, or virion, a Paramyxoviridae family member, and a member of the genus, Morbillivirus. The viral particle is 100-200 nm in diameter, with a core of single-stranded RNA, and is closely related to the rinderpest, and canine distemper viruses. Two membrane envelope proteins are important in pathogenesis. They are the F (fusion) protein, which is responsible for fusion of virus and host cell membranes, viral penetration, and hemolysis, and the HA (hemagglutinin) protein, which is responsible for adsorption of virus to cells. |