Infected

Infected is a custom game mode in Call of Duty: Modern Warfare 3 which started as a private match game mode before being released to the online community public playlist on February 5, 2012 for PlayStation 3 and Xbox 360, and on May 9, 2012 for PC.

Gameplay
The game starts with all players being survivors. In the upper left hand corner of the screen, there is a timer that starts with nine seconds counting down to the Infected. After the nine seconds, one player is randomly chosen to be infected. The survivors are the players who are not infected, hence the name "Survivors". The surviving players must hide from and kill the Infected to try and survive until time runs out; each game lasts five minutes. The Survivors spawn with an unknown weapon (depending on what the custom settings are) and must survive by killing the Infected or hiding. 50 points are given to Survivors every time a Survivor is Infected. The name given with the points is "Survivor". The round ends when either the last Survivor is killed/infected, or time runs out, and the new round will start pending on a new player to be infected.

However, there is a twist in public Infected. Any place where the players will be notoriously difficult to knife by normal circumstances is a 'death zone', wherein a player (including the Infected themselves) will automatically die and join the Infected (if not already). This also applied to Private Matches, but community outburst led to this being reversed in Private Matches. Notable are listed below in "Death Zones."

Another Infected variant has all the players begin as Juggernauts only armed with .44 magnums dual wielded, Scavenger Perk, and nothing else. As before, when the timer is up one player becomes the infected, and gains the Infect loadout: Striker, XM25, Semtex, Tactical Insertion, Sleight of Hand, Quickdraw, Steady Aim, and Dead Man's Hand, while keeping the Juggernaut suit. After one kill he loses his Juggernaut suit, but retains the loadout. As usual, the Juggernauts must kill the Infected; if any Juggernaut is slain he will transfer to the Infected team. The Juggernauts win if at least one person can hold out until the time is up; otherwise victory is forfeited and the infected win. It is also impossible to hide in this loadout, since the map is already too small, and the Infected radar always shows the Juggernaut icon.

Class loadouts
NOTE: There are many different class loadouts in the Infected game mode.

Striker and Five Seven

 * Primary Weapon: Striker (Extended Mags w/ Damage Proficiency)
 * Secondary Weapon: Five Seven (Akimbo)
 * Lethal Item: C4
 * Tactical Item: None
 * Perks: Scavenger, Hardline, Steady Aim
 * Rewards: Sleight of Hand, Quickdraw, Dead Silence
 * Bonus Perks: None
 * Death Streak: None

PP90M1 and .44 Magnum

 * Primary Weapon: PP90M1 (w/ Kick Proficiency)
 * Secondary Weapon: .44 Magnum (Akimbo)
 * Lethal Item: Claymore
 * Tactical Item: None
 * Perks: Scavenger, Quickdraw, Stalker
 * Rewards: Sleight of Hand, Dead Silence, Steady Aim
 * Bonus Perks: None
 * Death Streak: None

FMG-9

 * Primary Weapon: None
 * Secondary Weapon: FMG-9 (Akimbo)
 * Lethal Item: C4
 * Tactical Item: None
 * Perks: Scavenger, Hardline, Steady Aim
 * Rewards: Sleight of Hand, Quickdraw, Dead Silence
 * Bonus Perks: None
 * Death Streak: None

Type 95 and .44 Magnum

 * Primary Weapon: Type 95 (With Red Dot Sight)
 * Secondary Weapon: .44 Magnum (Akimbo)
 * Lethal Item: Claymore
 * Tactical Item: None
 * Perks: Scavenger, Quickdraw, Stalker
 * Rewards: Sleight of Hand, Dead Silence, Steady Aim
 * Bonus Perks: None
 * Death Streak: None

Barrett .50 Cal. and Five Seven

 * Primary weapon: Barrett .50 Cal (Attachments proficiency providing Extended mags and Heartbeat sensor)
 * Secondary Weapon: Five Seven (Akimbo)
 * Lethal Item: Bouncing Betty
 * Tactical Item: None
 * Perks: Sleight of Hand, Hardline, Steady Aim
 * Rewards: Quickdraw, Assassin, Marksman
 * Bonus Perks: Scavenger (Survivors do not start with extra ammo the Pro variant provides. They must acquire a blue pack after every kill to keep themselves supplied.)
 * Death Streak: None

Striker vs. Jugg

 * Primary Weapon: None
 * Secondary Weapon: .44 Magnum (Akimbo)
 * Lethal Item: None
 * Tactical Item: None
 * Perks: Scavenger
 * Rewards: None
 * Bonus Perks: None
 * Death Streak: None
 * Juggernaut Enabled

Default

 * Primary Weapon: None
 * Secondary Weapon: Empty USP .45 with Tactical Knife
 * Lethal Item: Throwing Knife
 * Tactical Item: Tactical Insertion
 * Perks: Extreme Conditioning and Quickdraw, Dead Silence granted in some cases
 * Rewards: None
 * Bonus Perk: Either Marathon, Lightweight or both. Grants a speed boost similar to the effects of Juiced
 * Death Streak: Juiced

Striker vs Jugg

 * Primary: Striker with Extended Mags and Range proficiency
 * Secondary: XM25
 * Lethal Item: Semtex
 * Tactical Item: Tactical Insertion
 * Perks: Sleight of Hand, Quickdraw and Steady Aim
 * Rewards: None
 * Bonus Perk: None
 * Death Streak: Dead Man's Hand

"First Infected"
The game starts with a nine second countdown where a random player becomes the "First Infected". Once the first player becomes infected, he doesn't start out with the knife loadout, but rather at first uses the current Survivor loadout (example: the first Infected will still be holding his Striker). Albeit, it comes with the Throwing Knife, Tactical Insertion, and the Infect Perks. The First Infected uses the gun to infect a second person. Once this is achieved, the Infected will then use their knife loadout for the remainder of the match.

In the case of the Barrett loadout, the First Infected will use an ACR 6.8 w/ Silencer to give an edge in Infecting the next victim, since it is more effective than attempting to spray and pray, or even attempt to quickscope a second victim.

When there are only two Infected, if one of them leaves, then the other becomes "First Infected" again, and must infect another player to continue the cycle and the game.

Final Survivor
When there is one Survivor left, that player will be notified as "Final Survivor". The 17 Infected have the rest of the game to search the entire map for the last Survivor. Generally, the Survivor would be hiding in a patch of grass in a place that is mostly overlooked, so the Infected have to make sure they look at every piece of scenery and environment around every corner of the map (it is also very difficult in the Barrett loadout, where the Survivor is wearing a Ghillie Suit). Half of the time, the Survivor will be making his last stand on the popular camping spots of the maps, such as the catwalks on Dome, or the street side of Underground, so the Infected just simply have to swarm the survivor.

When the Survivor has not been located for a while, a radar pings every 10-15 seconds, showing the red dot where he is hiding. If the Survivor has earned Assassin (via Specialist Bonus), the radar effect is negated and he won't appear on the minimap. If the MOAB has been activated, the radar is useless for the 60 seconds it is active.

If there are less than 17 Infected and a Final Survivor, if a new player connects into the lobby, the connecting player becomes a new Survivor and the Final Radar is disabled until the Final Survivor. This poses a problem for the Infected who are already searching hard for the Final Survivor, only to find out an anonymous Survivor has entered the game and delayed their victory, or when the "final" Survivor has finally been killed, the game still hasn't ended because a new Survivor has just connected. This could be frustrating especially when the game is coming down to the final seconds, the new Survivor connects and just hides long enough for the game to end and the Survivor wins.

Death zones
These are a list of "death zones" that are present in public infected.
 * The van in the loading dock in Arkaden.
 * The signpost in Underground, just after a window where the destroyed trains are.
 * The signpost in Resistance, leading to the magazine stall.
 * The top of some roofing, just near the Black Hawk, as well as the top of the downed Black Hawk in Bakaara.
 * The potted bush, opposite of the top of the escalators in Arkaden.
 * The edge of a building roof in Seatown, near the restaurant in the far south-east corner of the map.
 * The propane tanks sitting on a truck bed near the yellow bulldozer in Hardhat.
 * The barrels behind the fenced forklift vehicle in the middle of Hardhat.
 * The lampost near the top left of Downturn, just near the destroyed fire engine.
 * The crane basket near the top right of Downturn.
 * The ledge in the bottom left of Downturn, just next to the Marley and Griffin trucks.
 * The broken steel window of the southwest ship - sometimes, some players still manage to get over and into the seemingly impossible ledge in the corner down there. Because the last Survivor who knows this glitch tends to camp there, the rest of the Infected would always crowd in there, making it extremely difficult to reach in there and even more difficult to attempt a Throwing Knife.

Call of Duty: Ghosts
Infected returns in Call of Duty: Ghosts. As a Survivor, the loadout consists of only the Bulldog shotgun, and an IED. The Infected use a Combat Knife, a Throwing Knife and a Tactical Insertion, along with having a noticably faster speed and a longer sprint endurance. At the start of the game, players have 15 seconds until a random Survivor turns. Instead of a Combat Knife, the first Infected will sport an M9A1 pistol until another Infected joins their team.

Trivia

 * Infected players have normal multiplayer character models.
 * Survivors can die and become infected without an infected killing them e.g. if a survivor jumps and falls to their death, blows themselves up with a vehicle or with C4/ claymore/ Bouncing Betty etc.
 * If the player acquires Juggernaut, infected players will show a unique Juggernaut armor with a black finish instead of the whitish armor.
 * While playing online, though the Infected are sometimes listed to have no third perk, they do not suffer from falling damage, as if they had Dead Silence Pro, though their foot steps can nevertheless be heard. Also, the Featherweight challenges can be achieved this way, even if the player does not have said perk.
 * A Host Migration can occur if the 'first infected' ends the game, thus causing the network to reboot and randomly choose another person.
 * The playlist has been updated multiple times such as: adding Throwing Knife, Specialist Strike Package; taking out game modes such as MK46 vs Jugg etc.
 * The PP90M1 originally had extended mags, but was later removed.
 * This game mode is unavailable for the Wii.
 * The variant 'Striker vs Jugg' is the only mode where infection personnel can continuously use weapons and explosives and gain ammunition.
 * Unlike other game modes, in which kills scored by a Juggernaut show up with the Jugg killfeed, 'Striker vs Jugg' will show the actual weapon with which the Infected was killed.
 * The variant 'Striker vs Jugg' is available only on Dome.