dog and cat assay data sheet

Demodex gatoi mites (mange) in cats

Test code: X0035 - Ultrasensitive qualitative detection of Demodex gatoi mites in cats by real time polymerase chain reaction

 Demodectic mange (demodicosis) is an inflammatory skin condition caused by Demodex mites that cannot be easily detected by naked eye. Two different species of Demodex mite (Demodex gatoi and Demodex cati) can cause mange in cats. (Recently, a third species of feline Demodex mite has been identified, but it is unclear whether this third species also causes mange.) These feline Demodex species have distinct genotypes and do not cluster in one genetic clade.

D. gatoi differs from D. cati in several respects. D. cati is a long, thin mite that lives inside hair follicles, while D. gatoi has a distinctive stubby appearance and instead dwells in the keratin layer of the epidermis. D. cati is considered a normal resident of feline skin; localized D. cati infection is usually self-limiting and does not necessarily indicate an underlying cause. If a D. cati infection becomes more generalized, it may indicate underlying immunosuppression that is allowing the mite to multiply uncontrolled. Therefore when generalized D. cati infection is seen, testing for feline leukemia virus, feline immunodeficiency virus, or other immunosuppressive conditions should be considered. Generalized D. cati infection may also be associated with medications that suppress the immune system.

D. gatoi however is not a normal commensal on domestic cats, and specific treatment is often required to eliminate D. gatoi infection and avoid spreading it to other cats. Cats infected with D. gatoi will develop symptoms such as extreme itchiness; hair loss around the eyes, head, neck and flank; and in some cases, skin lesions. D. gatoi is easily spread between cats in a household or at cat shows.

Many cats infected with D. gatoi develop symptoms that are clinically indistinguishable from allergic skin disease; thus D. gatoi should be considered in the differential diagnosis when cats are suspected of having allergic skin disease. Some cats infected with D. gatoi can be asymptomatic carriers, spreading the infection to other cats. Therefore all cats that have had contact with an affected cat should also be tested.

Microscopic morphological examination of hair samples, skin scrapings or feces is sometimes attempted for diagnosis of Demodex mites. However, morphological differentiation between D. gatoi and D. cati is not easy and misdiagnosis frequently happens. On the other hand, detection and differentiation of these mite species by polymerase chain reaction is fast, specific and sensitive (Frank et al., 2013).

Utilities:

• Help confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of Demodex gatoi mange in cats
• Help ensure that households and catteries are free of this mite
• Help prevent the spread of Demodex gatoi mites between cats at shows
• Minimize human exposure to this mite
• Inform the design of an appropriate treatment regimen for affected cats

Specimen requirements: Swab or sterile toothbrush run deeply through hair and against skin for at least 30 seconds, or environmental surface swab, or skin scraping, or skin lesion swab.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected