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Evidence of immunosuppression by Demodex canis
O O Barriga1, N W al-Khalidi, S Martin
1Department of Veterinary Preventive Medicine, Ohio State University, Columbus 43210.
Veterinary Immunology and Immunopathology
|April 1, 1992
Summary
Generalized demodectic mange (GDM) in beagles is linked to immunosuppression, which appears after clinical signs emerge. This suggests the parasite or the host’s response triggers the immune suppression observed in GDM dogs.
Area of Science:
- Veterinary Immunology
- Canine Dermatology
- Parasitology
Background:
- Demodectic mange is a common skin disease in dogs caused by Demodex mites.
- The relationship between mange severity and the host's immune status requires further investigation.
- Lymphocyte blastogenesis assays are used to assess immune cell function.
Purpose of the Study:
- To investigate peripheral blood lymphocyte responses in beagles with varying degrees of demodectic mange.
- To determine if immunosuppression precedes or follows clinical manifestations of generalized demodectic mange (GDM).
Main Methods:
- Peripheral blood lymphocyte blastogenesis assays were performed on clinically normal beagles, beagles with localized demodectic mange (LDM), and beagles with GDM.
- Lymphocytes were stimulated with mitogens including Concanavalin A (Con A), Phytohemagglutinin (PHA), and Lipopolysaccharide (LPS).
- Assays were conducted at 1-3 weeks and 4-6 weeks post-clinical sign appearance.
Main Results:
- Lymphocyte responses were generally normal in healthy and LDM beagles, with a transient increase in PHA response in LDM dogs at 1-3 weeks.
- A moderate inhibition of Con A response was observed in LDM dogs at 4-6 weeks.
- Generalized demodectic mange (GDM) dogs showed severely depressed lymphocyte responses to all mitogens at 4-6 weeks.
Conclusions:
- Immunosuppression in GDM dogs appears to be a consequence, not a precursor, of clinical disease.
- The findings suggest that the Demodex parasite or the host's immune reaction to it induces immunosuppression in GDM.
- This study highlights the importance of immune status assessment in canine demodectic mange management.