Pronunciation: [smˈɔːlpɒks vˈa͡ɪɹəs] (IPA) 
The word "smallpox virus" is spelled using the International Phonetic Alphabet (IPA) as /ˈsmɔːlpɑːks ˈvaɪrəs/. The "s" at the end of "smallpox" is pronounced as a "z" sound because it is followed by a vowel sound. The "o" in "pox" is pronounced as a long "o" sound, while the "x" is pronounced as a "ks" sound. The word "virus" is pronounced with a long "i" sound and a short "u" sound followed by a silent "s" at the end.
Smallpox virus is a highly contagious and infectious virus belonging to the family Poxviridae and the genus Orthopoxvirus. It is the causative agent of the severe and often deadly disease known as smallpox. This viral infection is characterized by high fever, distinctive skin rash, and the formation of fluid-filled lesions that progress into pustules.
The smallpox virus is large and brick-shaped, measuring approximately 200-300 nanometers in size. It contains a double-stranded DNA genome and is densely covered with surface proteins. The virus is stable and can persist for extended periods of time in the environment, making it a significant global health concern.
Transmission of the smallpox virus primarily occurs through respiratory droplets released when an infected person coughs or sneezes. It can also be spread through direct contact with infected bodily fluids or contaminated objects. The virus enters the body through the respiratory tract, swiftly spreading to the lymph nodes, and subsequently reaching the bloodstream.
Historically, smallpox virus has caused devastating outbreaks and epidemics worldwide, resulting in high mortality rates. However, due to successful global eradication efforts, smallpox is the only human disease to have been eradicated to date, with the last known natural case occurring in 1977.
Immunization through vaccination has played a crucial role in eradicating smallpox. Vaccination with the vaccinia virus, a closely related virus to smallpox, provides long-term immunity against the disease.
The word "smallpox" originated from the Middle English term "smale pokkes", which translates to "small pustules". "Small" refers to the size of the skin lesions caused by the disease, while "pox" refers to the pustules or sores that develop on the skin. The term "virus" is derived from Latin, where it originally meant "poison" or "slimy liquid". It later evolved to refer to any infectious agent that can cause disease. Therefore, the term "smallpox virus" specifically refers to the virus responsible for the smallpox disease.
