Engraving from 1811 depicting pustules on cow udders.
The cowpox is an infectious disease caused by an animal orthopoxvirus, the cowpox virus (CPXV or CowPoX Virus). It is a zoonosis transmissible to other species such as cats, and in particular to humans. It presents as a disease similar to human smallpox, but much milder, most often limited to local skin lesions.
Like all orthopoxviruses, cowpox exhibits cross-immunity with smallpox. This empirical observation, made by Edward Jenner (1749-1823), led him to create “vaccination” in 1798, a term derived from the Latin cow meaning “cow”.
The disease called cowpox by Jenner was already known to farmers and people who regularly worked with livestock, especially cow milkers. In France, it was called picote. Even before Jenner, it was known that farmers with cowpox or picote lesions were relatively spared during smallpox epidemics.
The animal disease remained fairly rare, but regularly reported, with occasional transmission to humans through contact with infected cows until the 1970s. Since then, cowpox cases in cattle have continued to decline, but reports of other affected species, both domestic and wild, have increased.[1].
Poxviridae are DNA viruses that replicate in the cytoplasm, outside the nucleus. Since DNA replication and transcription normally take place inside the nucleus, these viruses require a large genome to encode the enzymes and proteins needed for the virus’s replication steps. Other viruses, such as Adenovirus, penetrate the nucleus and hijack the host’s cellular machinery in order to replicate.
The virus is found in Eurasia: Europe (United Kingdom, France, Austria, Norway, etc.) and in Central and Northern Asia (Russia, Turkmenistan). Human cases are very rare today and are most often contracted from domestic cats. The virus is not commonly found in cattle.
The natural reservoir of the virus is thought to be forest rodents such as Apodemus sylvaticus or Myodes glareolus[1].
Symptoms in cats include lesions on the face, neck, forelimbs and paws, and less commonly upper respiratory tract infections. Symptoms of cow virus infection in humans are localized pustular lesions usually found on the hands and limited to the site of introduction.
- (en) Frank Fenner et Donald Henderson (épidémiologiste), Smallpox and its eradication, Geneve, WHO, 1988, 1460 p. (ISBN 92-4-156110-6, read online).
- Jean-François Saluzzo, SmallpoxParis, PUF, coll. “What do I know?” no. 3690, 2004. (ISBN 2-13-053409-0)
- ↑ a et b Natalia Ingrid Oliveira Silva, Jaqueline Silva de Oliveira, Erna Geessien Kroon et Giliane de Souza Trindade, « Here, There, and Everywhere: The Wide Host Range and Geographic Distribution of Zoonotic Orthopoxviruses », Virusesvol. 13, no. 1, December 30, 2020, p. 43 (ISSN 1999-4915PMID 33396609PMCID 7823380DOI 10.3390/v13010043, read onlineaccessed August 18, 2024)
