A project of the New Mexico AIDS Education and Training Center. Partially funded by the National Library of Medicine
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Fact Sheet Number 514
MYCOBACTERIUM AVIUM COMPLEX (MAC)
WHAT IS MAC?
Mycobacterium Avium Complex (MAC)
is a serious illness caused by common
bacteria. MAC is also known as MAI
(Mycobacterium Avium Intracellulare).
MAC infection can be localized (limited
to one part of
your body) or
disseminated (spread through your
whole body, sometimes called DMAC).
MAC infection often occurs in the lungs,
intestines, bone marrow, liver, and
The bacteria that cause MAC are very
common. They are found in water, soil,
dust, and food. Almost everyone has
them in their body. A healthy immune
system will control MAC, but people
with weakened immune systems can
develop MAC disease.
Up to 50% of people with AIDS may
develop MAC, especially if their CD4
cell count is below 50. MAC almost
never causes disease in people with
more than 100 CD4 cells.
HOW DO I KNOW IF I HAVE
The symptoms of MAC can include high
fevers, chills, diarrhea, weight loss,
stomach aches, fatigue, and anemia
(low numbers of red blood cells). When
MAC spreads in the body, it can cause
blood infections, hepatitis, pneumonia,
and other serious problems.
Many different opportunistic infections
can cause these symptoms. Therefore,
your health care provider will probably
check your blood, urine, or saliva to
look for the bacteria that causes MAC.
The sample will be tested to see what
bacteria are growing in it. This process,
called culturing, can
weeks. Even if you are infected with
MAC, it can be hard to find the MAC
If your CD4 cell count is less than 50,
your health care provider might treat
you for MAC, even without a definite
is because MAC
infection is very common but can be
difficult to diagnose.