Mycobacterium Avium Complex in Dogs

Category: Immune System
Inheritance: Autosomal recessive
Breeds documented: 1
Published sources: 3

Overview

Bacteria in the Mycobacterium avium complex, or MAC, can cause widespread infection. The infection can affect the liver, spleen and intestines. Most dogs naturally resist these bacteria. In some Miniature Schnauzers, a change in the CARD9 gene weakens the body's defenses and raises the risk of developing infection after exposure.

Signs to watch for

Weight loss
Less interest in food
Unusual tiredness or low energy
Vomiting or diarrhea
Sometimes, swellings beneath the skin

In reports largely involving breeds with inherited infection risk, signs most often appeared within the first three years.

When to get help Book a vet visit within 24 hours for sudden weight loss or a new painless lump.

Diagnosis and tests

Vets can collect cells with a fine needle or take a small tissue sample from an affected area. Special stains and a microscope help detect mycobacteria, the wider group that includes MAC. Specialist laboratories identify the bacteria by growing them or testing their DNA. A separate DNA test screens Miniature Schnauzers for the CARD9 change linked to inherited infection risk.

Breeds with documented risk

1 breed

By breed size

1 Small

Miniature SchnauzerSmall · Terrier Group

Inheritance

Autosomal recessive
Miniature Schnauzer
A dog is affected only if it inherits two copies of the gene variant, one from each parent. A dog with one copy is a carrier: usually healthy, but able to pass the variant on. When two carriers are bred, on average one puppy in four is affected. A DNA test can tell clear, carrier and at-risk dogs apart.
As stated by OMIA

We've gathered what published sources say about this condition, so you can talk it through with your vet. It isn't veterinary advice: you and your vet know your dog best.