Comparison of cryofixation methods for skin biopsies from sheep infested with Psoroptes ovis (Acari: Psoroptidae).

Two methods of cryofixing skin samples from sheep infested with Psoroptes ovis were compared. In one method the skin biopsy was placed in a capped vial before immersion, while the other allowed direct contact with liquid nitrogen. No statistically significant differences were found between the cryofixation methods with regard to location of P. ovis sections or engaged mouthparts. Direct contact with liquid nitrogen is recommended as the preferred method for cryofixing epidermal feeding ectoparasites on skin samples.