Case description: 4 captive adult Micronesian kingfishers (Halcyon cinnamomina cinnamomina) at 3 zoologic institutions were examined routinely or because of dyspnea or lethargy.
Clinical findings: All birds had marked hepatomegaly. Two birds had dyspnea caused by compression of air sacs by the enlarged liver, and 1 bird had generalized weakness and lethargy. Three birds had distended coelomic cavities, and 3 birds were thin or had lost weight. There were no consistent abnormalities in blood analytes. Results of most ancillary diagnostic tests such as acid-fast staining of cloacal or fecal swab specimens and culture of feces for acid-fast bacteria were negative. Results of examination of hepatic biopsy specimens in 2 of 4 birds were suggestive of mycobacteriosis.
Treatment and outcome: 3 birds died or were euthanized soon after diagnosis. One kingfisher was isolated and monitored for 4 months without treatment and died during anesthesia for disease monitoring. Postmortem histologic examination revealed histiocytic hepatitis and acid-fast bacteria in all 4 birds. Bacteriologic culture of liver specimens yielded Mycobacterium simiae complex in all 4 birds.
Clinical relevance: Infection with M simiae complex should be considered in ill Micronesian kingfishers, and further monitoring is warranted to determine whether this is an emerging pathogen in this species.