http://ratguide.com/health/integumentar ... asites.php
Mites under normal conditions are commensal in small numbers and do not tend to be bothersome to their host. It is when the rat is stressed, has a decreased immunity due to other illnesses, and/or is unable to keep the numbers reduced by normal grooming that causes the mites to flourish in numbers. Inattention to proper husbandry, a rat that is ill, or giving ineffective treatment can lead to reinfestation, and dermatitis. On the average the entire life cycle of the mite beginning with the eggs which hatch in about seven days through the larval, nymphal, and adult stages requires approximately 23 days to complete. It is therefore important to maintain care and follow through with treatment(s) prescribed.
(Commensal = n. An organism participating in a symbiotic relationship in which one species derives some benefit while the other is unaffected. )
Only Buddy is showing the symptoms but they are all infected.
Classic shoulder scabs from mites
Head, cheek and chin scabs on poor Marty
There were 4 boys in the cage.
Marty was most scabby, Webster was 2nd, Charlie had a couple, and Calloway (healthiest and youngest) had none...they were all treated, and I realized afterwards they were all scratching more than they should've and were "infected"