MAC

MAC – Mycobacterium Avium Complex

Mycobacterium Avium Complex refers to a rare but lethal defect of the immune system that allows an overwhelming systemic infection in affected dogs. It has been identified in Bassett Hounds, Yorkies, Boxers, German Shepherds, Shih Tzus and Miniature Schnauzers as well as other mammals including cats and man. In the Miniature Schnauzer, it was found to be limited to a specific line of Miniature Schnauzers and was first noted in 1990’s.

The AMSC Health Committee was able to secure and fund, with the help of member Carole Weinberger, the services of a top veterinary researcher at the University of Pennsylvania, Dr. Urs Giger.  The American Miniature Schnauzer Club worked with the AMSC Health Committee and Breeders collecting samples and closely collaborating with Dr. Giger for several years.  While the numbers of affected dogs remain small comparatively, it is considered a serious and lethal disease and is included here not because of its prevalence but because of its devastating and fatal outcome and the need to ensure world-wide awareness of this disease and research. Because of broad testing in the Miniature Schnauzer community and through the strong support of Breeders, the incidence of this disease is very small although a rare case will present.

Signs of systemic illness include lethargy, in appetence, weight loss, fever, lymph node enlargements, and/or oculonasal discharge to varying degrees. Other symptoms that may not be observed in all cases include lameness, blood in the stool, diarrhea, pale mucous membranes, and abdominal distension. Not every veterinary clinician is aware of MAC infections and this immunodeficiency condition in schnauzers, and thus the diagnosis may be missed or delayed. Often symptoms mimic that of lymphoma but MUST be differentiated by specific testing and pathology. Any presumptive diagnosis of MAC or lymphoma must be confirmed by appropriate testing.

With the help of Dr Urs Giger, now retired, the AMSC was successful in almost totally eliminating this disease from the purebred Miniature Schnauzer.  The importance of this effort cannot be understated.  Developing this test has been instrumental in saving  our beloved Breed from this disease.  We will be forever indebted to Dr Giger and to the Breeders who gave of their time to solve this devastating health concern.

Below you’ll find a slide presentation of Dr. Gigers, the audio version of the presentation and information about MAC.

The AMSC Health Committee continues to endorse Dr. Giger’s recommendation to test all breeding dogs. The Health Committee has noted that one of the reasons for supporting this recommendation is that there have been at least 3 cases known where by Newsprint, Future Shock nor ANY other known producer on at least one side of the pedigree and one specifically, Swingtail Gale Warning, who does not have Newsprint, Future Shock, nor any known producer on EITHER SIDE of the pedigree. This dog was diagnosed with MAC – see here (PDF) for more.  Further, the scientific article published just recently in 2024 that describes the work and findings of the study that ultimately eliminated this devastating disease from Miniature Schnauzers is noted below:

Mizukami, K., Dorsey-Oresto, A., Raj, K., Eringis A, Furrow, E., Martin, E., Yamanaka, D., Kehl, A., Kolicheski, A., Jagannathan, V., Leeb, T., Lionakis, M.S., Giger, U. Increased susceptibility to Mycobacterium avium complex infection in miniature Schnauzer dogs caused by a codon deletion in CARD9. Sci Rep 14, 10346 (2024). https://doi.org/10.1038/s41598-024-61054-x

MAC Results (Updated 9-12-22)

“No entry is made to this list without an actual copy of the PennGen Result Report.”

Complete listing of MAC results (PDF)

SWINGTAIL GALE WARNING Pedigree (JPG)

NOTE: These web pages are provided as information only and do NOT represent Veterinary medical advice. Owners should discuss their pet’s needs with their Veterinarian who will be up to date on current protocols and advances in Veterinary Medicine.