Thanks for sending the note around. OE is a common and naturally occurring parasite, but it is still important to make sure that we monarch enthusiasts don't unintentionally increase prevalence in the wild.
What I might do with OE-infected monarchs is to release them if they are likely to be a natural infection, but do not release/freeze otherwise. For example:
If the monarch was wild-caught as an adult, then treat this as a natural infection and release back to the wild.
If the monarch was collected as a late instar larva from outdoors and reared indoors, then treat as a natural infection and release.
If the monarch was purchased from a grower or obtained from eggs laid in captivity, then freeze any OE infected individuals.
If the monarch was collected as an egg or early-instar larva and reared indoors, and if materials were not carefully sterilized prior to rearing, then freeze any OE infected individuals.
On our webpage monarchparasites.org we have suggestions for how to rear monarchs to limit the unintentional transmission of OE.
All the best, Sonia
Sonia M. Altizer, Associate Professor
Associate Dean of Academic Affairs
Odum School of Ecology
University of Georgia
Athens, GA 30602
URL: www.uga.edu/altizerlab www.ecology.uga.edu/altizer