Mycobacterium avium ss is the most common cause, although M genavense has been isolated from some psittacine birds. Seroagglutination tests of isolates are recommended to differentiate strains of M avium that cause disease in chickens and birds from those that fail to produce disease in these species. M tuberculosis, the cause of tuberculosis in people, has infrequently been isolated from parrots and canaries. M avium is very resistant; it can survive in soil for ≥4 yr, in 3% hydrochloric acid for ≥2 hr, and in 2% sodium hydroxide for ≥30 min.