Alastrim

Alastrim, also known as variola minor, is the milder strain of the variola virus that causes smallpox.

Variola minor is of the genus orthopoxvirus, which are DNA viruses that replicate in the cytoplasm of the affected cell, rather than in its nucleus. Like variola major, alastrim is spread through inhalation of the virus in the air, which can occur through face-to-face contact or through fomites. Contagion with variola minor confers immunity against its more dangerous form, variola major.