View source for Pokérus

The '''Pokérus''' is a special [[status condition]] that a [[Pokémon]] may get, first appearing in the [[Generation II]] games. Unlike other status conditions, however, it cannot be healed at a {{g|Center}} or with any [[status ailment healing item]], and can only be obtained by the Pokémon in question once. When a Pokémon has had the Pokérus, it gains double the [[effort points]] it would otherwise (i.e., fighting a {{p|Magikarp}} will give two {{stat|Speed}} EVs, rather than one). The virus takes about two days to wear off of an infected Pokémon, but the period of time can vary.

When it was introduced, the Pokérus had a 1 in 21,845 chance to be on a [[wild Pokémon]]. Through battling or capturing this wild Pokémon, {{player}}s could get this helpful virus onto their own Pokémon, and subsequently spread it around. Due to the overwhelmingly low chance of encountering the virus (about 1/3 of the chance to encounter a {{shiny2}} Pokémon), however, most players would never have a Pokémon with the virus.

In later generations, the Pokérus became more likely to get<!--how much?-->, with several event Pokémon during [[Generation III]] having it when transferred into a player's game, and with worldwide trading facilitated by the [[Nintendo DS]]'s Wi-Fi capabilities during [[Generation IV]], it is essentially ubiquitous. In fact, it is common courtesy to infect Pokémon to be traded on the GTS with Pokérus within some parts of the fandom.

==Infection==
When infected, a Pokémon's status screen will indicate it much as it does any other status condition, as <span style="background:#8822BB; color:#FFFFFF"><sup>P</sup><sub>K</sub><sc>rs</sc></span>. When another normal status condition, such as {{status|Sleep}}, affects the Pokémon, this will be displayed instead. As long as the Pokémon is infected with Pokérus, it can spread the virus to the other Pokémon in the player's party. The infection will spread if the infected Pokémon is in the main party after a battle. Pokémon that are put into the [[PC]] will keep the status indefinitely.

===In Generation II===
When the player first encounters the virus in one of the [[Generation II]] games, the nurse at the {{g|Center}} will make note of it when the Pokémon is first healed after contracting it, saying that there are "small life forms" on the Pokémon. After leaving the Pokémon Center, [[Professor Elm]] will call the player to tell them that the virus has no effect and will wear off.

===In Generation III===
The Pokérus operates in much the same way as in Generation II, though it can infect {{g|egg}}s too. Also, it can only be contracted or cured in {{3v2|Ruby|Sapphire|Emerald}}. In {{2v2|FireRed|LeafGreen}}, as well as {{pkmn|Colosseum}} and {{Pokémon XD}}, since the [[time]] function is absent, a Pokémon with Pokérus will keep it indefinitely, until it is transferred to the [[Hoenn]]-based games.

===In Generation IV===
The mechanics remain the same from Generation III. Additionally, much like storage in {{g|Box Ruby & Sapphire}} and in the PC, storage in [[My Pokémon Ranch]] will keep a Pokémon's Pokérus status indefinitely.

==After having the virus==

Once a Pokémon's immune system has fought off the virus, they cannot spread it further, nor can it be spread to them by other Pokémon.  In Generations II and III, a dot will appear on the Pokémon's status screen to indicate that they have had the virus previously, while in Generation IV, it will be a small smiley face.  Though the virus is gone, its positive effects will remain, most specifically the ability for that Pokémon to gain double [[EV]]s.

Any Pokémon on the player's party at the moment the system clock reaches midnight after a certain number of days in that position (number of days depends on the strain) will become immune.  An easy way to keep a "vessel" for future spreading is to always send the infected Pokémon to the box, {{pkmn|Daycare}}, {{pkmn|Stadium 2}} (in [[Generation II]], {{pkmn|Box}} (in Generation III), or [[My Pokémon Ranch]] (in [[Generation IV]]) before midnight.  The game also recognizes immunizing if the system is turned off and on again on the next day.

In [[Generation II]], if a Pokémon with any stage of Pokérus, active or cured, is traded back to [[Generation I]] or withdrawn from Stadium 2 by a Generation I game, all traces of that Pokémon having had the Pokérus will disappear.  This is because a Pokémon's Pokérus status is not saved in any form in the Generation I games.

[[Category:Game mechanics]]

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