Vaccine Storage

Coccidiosis vaccines must be maintained at storage temperatures between 3°C and 7°C (38°F and 45°F). 

At sub-zero temperatures

  • The water in the oocysts freezes
  • The spororzoites rupture and are killed

At temperatures greater than 7°C (45°F)

  • Sporozoites metabolize their internal energy stores (specifically amylopectin) at a more rapid rate to survive the high temperature
    • When the sporozoites are finally ingested, their ability to excystise from the sporocyst is reduced because their energy reserves have been depleted
    • If excystised, the sporozoites do not have enough energy to infect intestinal cells

Some coccidiosis vaccine manufacturers aim to compensate for the coccidia's limited lifespan by increasing the number of oocysts per dose. However, this is technically not possible since all the sporulated oocysts start off with roughly the same amount of energy source (amylopectin). It also increases the risk of severe post-vaccination reactions, especially if the vaccine is used too soon after manufacturing, resulting in too many infectable oocysts per dose being administered.