MAC or Mycobacterium Avium Complex refers to an extremely rare but lethal defect of the immune system that allows an overwhelming systemic infection in affected dogs.This disease was first noted in the 1990s and was thought to occur in a specific line of Miniature Schnauzers.While the numbers of affected dogs remains extremely low, it is considered a serious and lethal disease.  A DNA test has been developed and clinical research continues to be done by Dr. Urs Giger at the University of Pennsylvania, College of Veterinary Medicine and all cases are referred to his lab at the University.

MAC Results (Updated 7-5-20)

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

Complete listing of MAC results

 The following is a note from Dr. Giger after his presentation at our AMSC meeting in Audubon, PA on 10-8-16

It was a great pleasure to meet the leadership and members of the AMSC and present our recent discovery. An account with power point slides and text is posted. Apparently the members are embracing the screening of miniature schnauzers for MAC. We had a great evening reviewing what is known and how to take the best approach to healthy Miniature schnauzers.

We have a couple of requests:

Please let us know if you have an infected dog – we will test the dog free of charge and also like to get blood samples to study the immune dysfunction.

We also like to hear from owners who had dogs with aspergillosis or skin infections as we like to see if those were related to MAC

Thank you

Urs Giger, Prof. Dr. med. vet., MS, FVH
Dipl. ACVIM & ECVIM (Internal Medicine)
Dipl. ECVCP (Clinical Pathology)

Click HERE for Dr. Giger’s Slide Presentation

Click HERE for the Audio version of that Presentation


We are thrilled to announce Dr. Giger & his team have been successful there is now a MAC DNA test!

In the links below you’ll find everything you’ll need to know about MAC & all the instructions for testing.

Consider this page a work in process & we will continue to update it as new information becomes available.

Postage for Mailing Swabs & other material far exceeded what we budgeted! If would be greatly appreciated if you would consider a donation to help offset these costs!! Many thanks from your AMSC Health Committee!


The AMSC Health Committee continues to support 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 for more information.

MAC Article by Dr. Urs GigerFrequently Asked Questions

MAC DNA Submission Instructions

Instructions for Sample Testing Collection 

PennGen Form Completion Tips    PennGen Address for Samples

NOTE: These Webpages 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.