Covering sickness, or dourine (French, from the Arabic darina, meaning mangy (said of a female camel), feminine of darin, meaning dirty), is a disease of horses and other members of the family equidae

Equidae

Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...

. The disease is caused by Trypanosoma equiperdum

Trypanosoma equiperdum

Trypanosoma equiperdum is a protozoan that causes Dourine, or covering sickness, in horses and other animals in the family equidae. The donkey shows no symptoms but is a carrier of this parasite. Unlike other species of Trypanosoma, this parasite can be sexually transmitted, also mother foal...

, which belongs to an important genus of parasitic protozoa

Protozoa

Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

, and is the only member of the genus that is spread through sexual intercourse. The occurrence of Dourine is Notifiable in the European Union under legislation from the OIE.