Mycobacterium avium

Introduction

M. avium, with other bacteria form the MAC that infect humans together. It infects one part of an individual’s body, like the lungs or intestines, or it could spread throughout your body. Some symptoms are: high fever or chills, diarrhea, weight loss, swollen glands, or anemia. More serious symptoms could be: blood infections, hepatitis, or pneumonia.

Hosts

Humans and Animals (especially birds and pigs). In humans, MAC infection especially affects individuals that are immunocompromised.

Transmission / Exposure Route

M. avium can be found in aerosolized water, piped hot water systems, bathrooms, house dust, soil, farm animals, and cigarette components. MAC is transmitted by inhalation in the respiratory tract or ingestion into the GI tract.

Case Fatality Ratio

MAC infection has a bigger impact on immunocompromised patients, like AIDS patients. The life expectancy of patients with AIDS and a MAC infection was 4 months, but recently, with the use of treatment, the prognosis is better. However, MAC infection in patients without the HIV infection does not cause any pain. In a study done, it was found that approximately 50% of patients were alive 5 years after the diagnosis.

Incubation Period

Can range from weeks to several months

Microbiology

A Gram positive, nonmotile, mycobacteria that is rod like in nature. MAC formed with other bacteria are considered to be nontuberculous mycobacteria.

Enviromental Survival

M. avium, according to a study done in Australia, thrives in warmer temperatures.