Blood in the Air is a symptom combo exclusive to the Necroa Virus DLC which causes zombies with heightened senses of smell to seek fresh blood. Severity increases when this combo is in play. Delirium and Hyperosmia are required. The Jaws achievement is earned for forming this combo.
| Symptom Combos in Plague Inc. and Plague Inc: Evolved. |
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| Assassin ▪ Bath Time ▪ Blind Genius ▪ Blood in the Air ▪ Boomer ▪ Carpe Jugulum ▪ Cranial Dispersion ▪ Discovery Channel ▪ Fly Magnet ▪ On The Naughty List ▪ Oops ▪ Profuse Bleeding ▪ Projectile Vomiting ▪ Public Defecation ▪ Red Ape Redemption ▪ Red Rain ▪ Rude Awakening ▪ Runner ▪ Spitter ▪ Swine Flu ▪ Tank ▪ Ultimate Christmas ▪ Vampire Bat ▪ Walking Contradiction ▪ Walking Dead ▪ Zombie Panic |
