Multidrug therapy of Mycobacterium avium subsp. avium infection in experimentally inoculated budgerigars (Melopsittacus undulatus)

MORTALITY TRENDS FOR BUDGERIGARS (MELOPSITTACUS UNDULATUS) HOUSED IN A WALK-THROUGH AVIARY IN A ZOO IN NORTH AMERICA, 2009-2019

Many zoos in North America feature walk-through exhibits that allow members of the public to interact with psittacine species, as these exhibits are popular with guests and can generate additional revenue. There is limited research available on the life expectancy and common causes of mortality of psittacines when group-housed in aviaries. This study compiled data on 496 budgerigar (Melopsittacus undulatus) mortalities at a walk-through aviary at a North American zoo from March 2009 to March 2019, including histopathology on 62 tissue sets collected post mortem, and gross necropsy data for 163 birds deceased from March 2015 to March 2019. The mean age at death or euthanasia of all fledged birds from 2015 to 2019 was 3.57 ± 1.58 yr. The most common causes of death or euthanasia found on gross necropsy were granulomatous disease (39.2%), trauma (16.0%), and Macrorhabdus ornithogaster (13.5%). The most common histologic finding was M. ornithogaster, described as the primary pathologic finding in 31.7% of submitted tissue sets, and recorded as a secondary pathologic finding in 53.2% of submitted tissue sets. Mycobacterial disease was the primary pathologic finding in 25.3% of submitted tissue sets, and was recorded as an additional pathologic finding in 35.4% of submitted tissue sets.

Monitored therapy of sporadic mycobacteriosis caused by Mycobacterium genavense in Atlantic canaries (Serinus canaria) and Bengalese finch (Lonchura striata)

Introduction

Mycobacteriosis is a significant disease of companion and wild birds which causes emaciation and widely distributed lesions, as well as being a potential zoonosis. Its primary aetiological agents in birds are Mycobacterium avium subsp. avium and the fastidious Mycobacterium genavense. This study monitored the therapy of birds naturally infected with Mycobacterium genavense to gain understanding of its effectiveness and the interrelation of co-infections with the disease course and pharmacotherapy.

Material and Methods

Five Atlantic canaries (Serinus canaria) and one Bengalese finch (Lonchura striata) with tentative diagnoses of mycobacteriosis resulting from M. genavense infection were treated twice daily with clarithromycin at 40 mg/kg, ethambutol at 30 mg/kg, and moxifloxacin at 10 mg/kg for 6 months. Two canaries were also found to be carriers of Cryptosporidium galli. Mycobacteria in faecal samples of all birds were investigated by bacterioscopy and quantitative PCR.

Results

Molecular tests yielded positive results for up to four months after treatment initiation for M. genavense and Cryptosporidium, but microscopy failed to detect the latter after four weeks in specimens from one canary. Co-infections with polyomavirus (in all birds) and circovirus and bornavirus (in canaries) were diagnosed. Two birds died during treatment and one was euthanised because of other disease, 1 month after treatment completion. Three canaries were in relatively good health a year after treatment.

Conclusion

Canary circovirus and polyomavirus co-infection may suppress the immune system and this may facilitate the development of mycobacteriosis. The set of drugs used led to the complete cure of mycobacteriosis in three canaries. In one bird the disease returned. Clarithromycin was the active drug against C. galli. Molecular methods serve well to monitor mycobacteriosis therapy and identify M. genavense and C. galli carriage.

Care and treatment of a rare Mycobacterium avium complex-infected wound: a case report

An unusual presentation of Mycobacterium avium complex (MAC), unlikely to be encountered in an outpatient dermatology setting, was diagnosed in a patient without an immunodeficiency. A 47-year-old woman, who was immunocompetent and had no risk factors, presented with a full-thickness, infected wound (large amounts of purulent exudate and severe pain) on her back, which had been present for two months. She was diagnosed as having an MAC infection, using a DNA microarray chip method. The patient underwent wound drainage and a fresh silver-containing dressing was applied daily for two months. Although systemic antibiotics were given for one week and anti-tuberculous medication for one month, there was no response. She also complained of bloating, nausea, loss of appetite and other problems, apparently due to drug-induced liver damage, confirmed by laboratory tests. Based on her characteristics and a literature review related to MAC infection, we implemented an individualised, holistic care protocol for the patient that included a daily diet of appropriate fresh vegetables and fruits, and adequate high-quality protein, aerobic exercises for two hours per day, and sleep for 6-8 hours per day, to alleviate the iatrogenic liver damage, improve immune function and reduce the stress response. The wound continued treatment with sharp debridement as needed, and fresh antimicrobial silver-containing dressings every other day. Wound size was measured once a week to evaluate the effects. The wound healed after 48 days, and the patient was followed-up for 18 months at the outpatient wound care centre and through social media. No recurrence or scar hyperplasia was observed.