Special Containment Procedures
SCP-593 is to be stored under standard Biosafety Level 4 precautions at all times. Use of a hazmat suit with self-contained oxygen supply is mandatory; entry and exit to any lab containing samples of SCP-593 must include multiple showers, ultraviolet light bombardment, a vacuum room, and regularly tested, electronically secured airlocks. Individuals suspected of infection with SCP-593 must be isolated from the general population under BSL-4 protocols immediately and kept in a darkened environment until the maximum infectivity and incubation period have both passed, generally a period of thirty days. Medical treatment of confirmed SCP-593 victims requires observation of BSL-4 protocols and the immediate incineration or immersion in acid of all materials with which the victims have had contact, along with any/all biological waste produced.
SCP-593 is a paramyxovirus of the genus Morbillivirus that exhibits a unique capacity for severe neurological damage after the onset of primary symptoms. The majority of its genome is identical to that of the measles virus, with a significant percentage of genetic material apparently derived from rinderpest virus (aka 'cattle plague' or 'steppe murrain'). Its contagion rate is equal to that of measles- ninety percent of individuals without immunity who share a household with an SCP-593 morbillivirus patient will develop the infection themselves within thirty days. Initial stages of infection are virtually identical to measles, beginning with a fever that may reach as high as 41° C. Koplik's spots appear on the victim's buccal and lingual mucosae early in the infection; unlike standard measles infections, however, the spots remain visible for two to three days.
Several days after the fever begins and conjunctivitis sets in, the victim's body is quickly covered in a generalized, erythematous, maculopapular rash that spreads from the head to the feet in less than a day. Ocular sensitivity to light also sets in around this time, and victims not confined to darkened areas or otherwise protected from light may suffer consequences up to and including total blindness. The rash generally turns from red in color to dark brown several days after eruption, at which point the neurological sequelae invariably set in.
The progression of symptoms begins with irritability and erratic behavior which may be mistaken for natural reactions to an unpleasant infection and confinement situation. However, myoclonic spasms and seizures swiftly follow. EEG examination of victims shows widespread cortical dysfunction; physical examination of victims' brains shows involvement of [DATA EXPUNGED] and significantly elevated gamma globulin titres. The true signature of the SCP-593 morbillivirus, however, lies in its permanent neurological effects. SCP-593 completely destroys the portion of its victims' brains that deals with concepts of number and mathematics. Its surviving victims literally cannot distinguish between 'two' and 'millions' or perform even the most rudimentary addition, let alone more advanced calculations. Counting accurately, even only from one to ten, is only possible by dint of memorization; if asked to determine whether one number is larger than another, survivors cannot give an accurate answer. Oddly, survivors are seldom if ever distressed by this fact unless forced by experimenters to work on mathematical problems, at which point they become defensive and often exhibit aggression.
SCP-593 was discovered in 20██ at ███ ███ ████ █████ ████████, ███ ████, in the form of several pressurized containers attached to the central HVAC equipment for the main trading floor. The initial outbreak was swiftly contained and damage control measures taken in the media, but the origin of the virus remains unknown. Investigation of all labs known to the Foundation to be capable of genetically engineering such an organism is under way.
Addendum: Despite its genetic similarity to measles and rinderpest, no vaccine currently exists for SCP-593. Attempts to attenuate the virus' strength for use as a live virus vaccine have so far proved useless; killed-virus vaccines do not appear to trigger the body's immune response. Immediate containment and isolation of all possible victims is recommended, as well as immediate investigation of outbreaks of measles in populations where measles vaccine uptake is normally historically high.