Retrospective Review of Mycobacterial Conjunctivitis in Cockatiels (Nymphicus hollandicus)
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Journal of Avian Medicine and Surgery 34(3):250–259, 2020
Ó 2020 by the Association of Avian Veterinarians
Retrospective Study
Retrospective Review of Mycobacterial Conjunctivitis in
Cockatiels (Nymphicus hollandicus)
Stephanie K. Lamb, DVM, Dipl ABVP (Avian), Drury Reavill, DVM, Dipl ABVP (Avian),
Dipl ABVP (Reptile and Amphibian), Dipl ACVP, Rebecca Wolking, BS, and
Bob Dahlhausen, DVM, MS
Abstract: The etiologic disease organism responsible for causing mycobacteriosis in avian
species is an acid-fast gram-positive bacterium. This bacterium causes granulomatous disease in
various internal organs, but in cockatiels (Nymphicus hollandicus) it has been commonly identified
within the conjunctival tissues. Twenty-six cases of mycobacterial conjunctivitis in cockatiels were
diagnosed through histopathologic assessment of diseased tissue samples, Fite acid-fast staining,
and polymerase chain reaction in this retrospective study. Clinicians who saw these cases were
contacted, and information was obtained regarding recommended treatment protocols prescribed
for the patients, the Mycobacterium species identified, and case outcomes. All patients in this
retrospective study had a biopsy performed on the affected conjunctival tissue, and because of the
small size of the patients, this excisional biopsy removed the affected tissue in its entirety or
significantly debulked the lesion. Of the 26 cases, 10 were lost to follow-up, 4 were euthanatized, 7
died, and 5 were alive at the time this information was submitted for publication.
Key words: Mycobacterium species, conjunctivitis, psittacine, avian, cockatiel, Nymphicus
hollandicus
INTRODUCTION cobacteriosis also infects humans and is considered
a zoonotic organism.1–9 With regards to avian
Mycobacteriosis is caused by bacterial species
species, mycobacterial infections have been isolat-
within the Mycobacterium genus, which are char-
ed from virtually every order. More than 130
acteristically acid-fast bacilli, aerobic, slow grow-
species of mycobacteria are currently recognized
ing, and highly resistant to extremes in
environmental conditions. Mycobacterium species and .10 of these species has been documented to
infections in avian species can result in devastating, infect birds.1,3 These Mycobacterium species in-
chronic, and often systemic disease. This genus of clude M avium subsp avium, M genavense, M
bacteria has affected many different domestic and tuberculosis, M bovis, M gordonae, M nonchromo-
nondomestic species, from cattle, sheep, and genicum, M fortuitum subsp fortuitum, M avium
rabbits to bears, giraffes, and rhinoceroses.1 Exotic subsp hominissuis, M peregrinum, M intermedium,
pet animals that have been diagnosed with M celatum, M intracellulare, M avium subsp
mycobacteriosis include reptiles, ferrets, hamsters, paratuberculosis, M africanum, and M simiae.1,3,5
amphibians, fish, and birds.1–9 Importantly, my- Several case reports describe cases of mycobac-
teriosis in pet psittacine birds. Psittacine birds that
From the Arizona Exotic Animal Hospital, 744 N Center St
commonly appear to be diagnosed with mycobac-
#101, Mesa, AZ 85201, USA (Lamb); Zoo/Exotic Pathology teriosis include budgerigars (Melopsittacus undu-
Service, 6020 Rutland Dr #14, Carmichael, CA 95608, USA latus), brotogerid parakeets (Brotogeris species),
(Reavill); Washington Animal Disease Diagnostic Lab, PO Box Amazon parrots (Amazona species), and pionus
647034, Pullman, WA 99164, USA (Wolking); and Veterinary
parrots (Pionus species).10–13 Postmortem surveys
Molecular Diagnostics, 5989 Meijer Dr, Suite 5, Milford, OH
45150, USA (Dahlhausen). have found Amazon parrots and cockatiels (Nym-
*Corresponding Author: Stephanie K. Lamb phicus hollandicus) to be the most commonly
stephlovesbirds@hotmail.com affected psittacine birds.14,15 Historically, specia-
250
LAMB ET AL—MYCOBACTERIAL CONJUNCTIVITIS IN COCKATIELS 251
period are reviewed. The species of mycobacterium
identified, the treatments patients received, and the
final disposition of the patient were evaluated.
MATERIALS AND METHODS
Records of avian submissions were reviewed
from Zoo/Exotic Pathology Service (Carmichael,
CA, USA) from 2000 to 2019. Inclusion criteria
included only cases from cockatiels that presented
with a final diagnosis of conjunctival mycobacte-
riosis determined by histopathologic evaluation of
submitted tissue samples and histochemistry (Fite
acid-fast staining) and confirmed by polymerase
chain reaction (PCR). Both biopsy and postmor-
Figure 1. A cockatiel included in this retrospective study tem samples were included. Veterinary hospitals
with a mass extending from the conjunctiva of the lower from which cases originated were contacted for
eyelid. A Mycobacterium species was identified as the follow-up information regarding the individual
pathologic bacterium that caused the disease condition. patients. Questions that were asked included if
and how the patient was treated, what species of
tion of mycobacteria was problematic because of mycobacterium was identified, and the final
the inherent difficulty in culturing the organism. disposition of the patient.
Therefore, most cases of mycobacteriosis in pet Two different laboratories were used to identify
birds were assumed to be from M avium-intra- the species of mycobacteria by PCR. Twenty-two
cellulare complex. However, in the early 1990s samples were evaluated by the Washington Animal
advances in isolation methods, including culture Disease Diagnostic Laboratory (Pullman, WA,
techniques and the use of molecular analysis, USA). Five samples were assessed by Veterinary
allowed for the identification of M genavense to Molecular Diagnostics Laboratory (Milford, OH,
be recognized as a more common cause of USA).
mycobacteriosis in pet psittacine birds.16–19 Of the samples evaluated by the Washington
Mycobacterial lesions can occur in any organ; Animal Disease Diagnostic Laboratory, DNA was
however, they are most often identified in the extracted from samples as previously described,
intestines, liver, spleen, and bone marrow.2,3,11,20 and the presence of M genavense was tested by
Less affected organs include the conjunctiva, real-time PCR targeting a portion of the heat
kidney, muscles, gonads, and endocrine organs.3 shock protein gene.25,26 Next, to confirm the DNA
Histologically, mycobacterial lesions are typically sequence, universal mycobacterial primers ampli-
granulomas and have a necrotic center surrounded fied a portion of the 16S–23S ribosomal internal
by macrophages, giant cells and heterophils.3,21 transcribed spacer (ITS) region in 15 of the
Although not frequently reported in the literature, samples, as previously described, and sequenced
granulomas of the conjunctiva of cockatiels are by an outside vendor (Genewiz, South Plainfield,
particularly common (Fig 1).21 NJ, USA).27 Basic Local Alignment Search Tool
Mycobacteriosis treatment regimens have been (BLAST; National Center for Biotechnology
extrapolated from human medicine and previous Information, Bethesda, MD, USA) was used to
case reports. Euthanasia is often recommended, analyze the consensus sequences.
but for those that do decide to treat, effective drugs For the samples that were submitted to the
include macrolides, fluoroquinolones, rifamycins, Veterinary Molecular Diagnostics Laboratory, a
tetracyclines, aminoglycosides, ethambutol, dap- real-time/quantitative polymerase chain reaction
sone, ethionamide, cycloserine, and clofazi- with primers MG22 and MG23 was used to
mine.5,22 Often antibiotic cocktails are prescribed amplify a 155–base pair (bp) segment of the M
to provide a more robust antibiotic treatment and genavense, hypothetical 21-kd protein gene (Gen-
reduce the chance for bacterial resistance. Combi- Bank AF025995.1).28 Primers Mycgen-f and My-
nations of medications and their dosages have been cav-r were used to amplify a 180-bp fragment
described and are available for birds.23,24 specific for M avium complex.29 The primers stated
In this retrospective study, cases of mycobacte- above were used for all 5 samples submitted to the
rial conjunctivitis in cockatiels over a 19-year Veterinary Molecular Diagnostics Laboratory.
252 JOURNAL OF AVIAN MEDICINE AND SURGERY
RESULTS triculus had severe, chronic, ulcerative gastritis
with transmural granulation tissue, and the kid-
Forty cases of avian mycobacterial conjunctivi-
neys had multifocal glomerular fibrosis and tubu-
tis were identified; however, only 26 of these cases
lar mineralization. Extramedullary hematopoiesis
met the inclusion criteria to be evaluated in the
was also found in the liver and spleen.
study. All cases were located within the United
The Mycobacterium species was identified in all
States and were from 10 different states, including
cases. M genavense was detected in 25 samples and
South Carolina, Utah, Arizona, Missouri, Colo-
rado, California, Florida, Louisiana, Washington, M avium was found in 1 sample. All 21 samples
and New York. The states that had the highest sent to Washington Animal Disease Diagnostic
proportion of cases evaluated in this retrospective Laboratory that were positive for Mycobacterium
study were California (10 cases), and Colorado (6 had 100% identity with M genavense GenBank
cases). The ages of the birds ranged from 2 to 15 Y14183. Of the 5 samples submitted to Veterinary
years; however, in 6 birds the age was not known. Molecular Diagnostics Laboratory, 4 of the
Eight birds were male and 15 were female, and in 3 samples revealed the species of mycobacterium to
birds, the sex was unknown. The presenting be M genavense. One of the samples identified M
complaints for the avian cases evaluated included avium.
chemosis, blepharospasm, erythema of the con- All cases had a biopsy performed to diagnose
junctiva, and ocular discharge. Although chemosis mycobacteriosis, which, for many, was macroscop-
was the most common clinical sign, not all patients ically a complete surgical excision because of the
had overt disease. Concurrent diagnosed diseases patient’s size. Nine of the 26 cases had a biopsy
were not evaluated for this investigation. All alone without any other treatments. Additional
patients in this retrospective study had a biopsy treatment was administered to 17 of 26 cases. Of
performed on the affected conjunctival tissue, and those that received additional treatment, 7 of 26
because of the small size of the patients, this had topical medication alone, 3 of 26 had oral
excisional biopsy surgically removed the affected medication alone, 4 of 26 had oral and topical
tissue in its entirety or significantly debulked the therapy, 1 of 26 had topical and injectable
lesion. Table 1 lists all treatments, final disposition, medication, and 2 of 26 had oral, topical, and
histopathology results, age, and sex of each patient injectable medications. Medical management con-
included in this study. sisted of antibiotic drugs and occasionally nonste-
All lesions were described as granulomatous roidal anti-inflammatory medication.
conjunctivitis (Fig 2), but some had further The final outcomes for the patients varied. Of 26
qualifications, which are described in Table 1. cases, 10 were lost to follow-up. Of those where
Lesions were subjectively considered moderate to follow-up data were available, 4 were euthanatized,
severe. One sample had a significant heterophilic 7 died, and 5 were still alive at the time this
infiltrate along with the granulomatous conjuncti- manuscript was submitted for publication.
vitis, whereas a separate sample had necrotizing Of the 7 birds that died, 4 died within 2 months
granulomas. Fite acid-fast staining was performed of diagnosis, with the earliest dying within 3 days
on tissue samples submitted from each case, and of diagnosing mycobacteriosis. Of these, 3 were
acid-fast microorganisms were identified in all prescribed topical medications, and 1 was treated
samples (Fig 3). with topical and injectable medications. An addi-
Two cases from which a biopsy of the conjunc- tional 3 birds died between 2 and 3 years after
tiva was used to confirm the diagnosis of myco- being diagnosed with mycobacterial conjunctivitis.
bacteriosis were also submitted for a full One of these birds was known to have died from
postmortem examination after death or euthana- egg binding, whereas the cause of death was not
sia. Granulomatous adrenalitis, multifocal mild determined in the other 2 cockatiels. Five birds
subacute interstitial nephritis with membranoglo- were still alive at the time of this writing. More
merulopathy, focally extensive granulomatous than a year had elapsed from the diagnosis of
enteritis, and multifocal nodular granulomatous mycobacterial conjunctivitis in all these individu-
air sacculitis, in addition to a focally extensive als. One individual was still alive 7 years after a
moderate to severe granulomatous conjunctivitis, diagnosis was obtained. Of the 5 birds that were
were identified in one case. In the second case, still alive at the time of this writing, 1 was not
chronic granulomatous conjunctivitis was recog- receiving any treatment, 2 were receiving topical
nized along with rare granulomas in the liver and treatments at times when an erythematous con-
adrenal glands. The isthmus region of the proven- junctiva was observed, and 2 were actively beingLAMB ET AL—MYCOBACTERIAL CONJUNCTIVITIS IN COCKATIELS 253
Table 1. Treatments, final disposition, histopathologic diagnosis, sex, and age of birds included in this retrospective
study of 26 cockatiels identified with conjunctivitis caused by Mycobacterium species over 19 years.
Bird no. Treatment Final disposition Histopathologic diagnosis Age, y Sex
1 Biopsy, enrofloxacin oral, Lost to follow-up Diffuse severe chronic active 6.5 M
doxycycline injectable, pyogranulomatous conjunctivitis
terramycin topical
2 Biopsy, ethambutol oral, Lost to follow-up Diffuse moderate to severe chronic 9 M
rifampin oral, granulomatous conjunctivitis with
isoniazide oral granuloma
3 Biopsy, rifampin oral, Still in treatment Granulomatous conjunctivitis 3 M
ethambutol oral, actively
ciprofloxacin oral
4 Biopsy, gentamycin Still in treatment Granulomatous conjunctivitis 5 F
topical, meloxicam oral actively
5 Biopsy alone Euthanatized Granulomatous conjunctivitis 10 F
6 Biopsy, tobramycin Died 2 weeks Biopsy: granulomatous conjunctivitis 3 F
topical postdiagnosis Postmortem examination: granulomatous
adrenalitis, multifocal mild subacute
interstitial nephritis with
membranoglomerulopathy, focally extensive
granulomatous enteritis, focally extensive
moderate to severe granulomatous
conjunctivitis and cellulitis, multifocal
nodular granulomatous air sacculitis
7 Biopsy, rifampin oral, Died 3 years after Severe granulomatous conjunctivitis 15 M
enrofloxacin oral, diagnosis,
ethambutol oral for 6 undetermined
months cause
8 Biopsy alone No treatment Diffuse severe granulomatous conjunctivitis 3 M
postsurgery, died
2 years
postdiagnosis,
undetermined
cause
9 Biopsy, meloxicam oral, Died from egg Severe chronic active granulomatous Unk F
gentamycin topical as binding 3 years conjunctivitis
needed for flare-ups after diagnosis
10 Biopsy, ofloxacin topical, Still in treatment Granulomatous conjunctivitis 6.5 M
flurbiprofen topical as PRN when
needed for flare-ups erythematous
conjunctiva
11 Biopsy, ofloxacin topical Still in treatment Right nictitating membrane necrotizing Unk F
as needed for flare-ups PRN when granulomas and granulomatous
erythematous conjunctivitis
conjunctiva
12 Biopsy alone Lost to follow-up Granulomatous conjunctivitis 10 F
13 Biopsy alone Lost to follow-up Granulomatous conjunctivitis 4 F
14 Biopsy, bacitracin, Died 9 days after Granulomatous conjunctivitis Unk Unk
neomycin, polymyxin diagnosis
topical
15 Biopsy alone Alive, no treatments Granulomatous conjunctivitis 5 Unk
currently
16 Biopsy alone Lost to follow-up Granulomatous conjunctivitis 5 F
17 Biopsy alone Lost to follow-up Diffuse moderate to severe chronic Unk F
granulomatous conjunctivitis with
multifocal granulomas and dense
fibroplasia254 JOURNAL OF AVIAN MEDICINE AND SURGERY
Table 1. Continued.
Bird no. Treatment Final disposition Histopathologic diagnosis Age, y Sex
18 Ciprofloxacin topical and Euthanatized Granulomatous conjunctivitis 4 M
meloxicam oral 2 years
before biopsy. Biopsy,
doxycycline injection
19 Biopsy, bacitracin, Lost to follow-up Granulomatous conjunctivitis Unk F
neomycin, polymyxin
topical
20 Biopsy, neomycin, Died 3 days after Granulomatous conjunctivitis 11 F
polymyxin, diagnosis
dexamethasone topical,
meloxicam oral
21 Biopsy alone Lost to follow-up Granulomatous conjunctivitis 10 Unk
22 Biopsy alone Euthanatized Granulomatous conjunctivitis 2 F
23 Biopsy, bacitracin, Alive, no treatments Granulomatous conjunctivitis 7.5 M
neomycin, polymyxin currently
topical 3 years
24 Biopsy, ciprofloxacin Died 2 months after Granulomatous conjunctivitis Unk F
topical, doxycycline diagnosis
injectable
25 Biopsy, ketorolac topical, Euthanatized Biopsy: granulomatous conjunctivitis 10 F
tobramycin topical, Postmortem examination: chronic
enrofloxacin oral, granulomatous conjunctivitis. Rare
meloxicam oral granulomas in the liver and adrenal glands.
Severe, chronic, ulcerative gastritis with
transmural granulation tissue in the
proventricular isthmus. Multifocal
glomerular fibrosis and tubular
mineralization of the kidneys.
Extramedullary hematopoiesis in the liver
and spleen.
26 Biopsy, ciprofloxacin Lost to follow-up, Granulomatous conjunctivitis 12 F
topical, flurbiprofen alive for 5 weeks
topical, gentamycin post-op
topical
Abbreviations: M indicates male; F, female; Unk, unknown; PRN, as needed.
treated with either oral or topical antibiotic literature describe ophthalmologic lesions in birds
therapy. with mycobacteriosis to include granulomatous
nodules in the conjunctiva, eyelids, and cor-
DISCUSSION nea.3,30–37 Corneal vascularization and edema have
Mycobacteria are bacterial organisms that can also been noted.37 Swellings in the periocular
result in an infectious disease that is often chronic region have been described, and serous-to-gelati-
in nature and causes granulomatous lesions in nous discharge has occasionally been observed.33,36
various organs and tissues of the body. This An Amazon parrot that was presented with
retrospective study evaluated mycobacteria local- conjunctivitis, chemosis, and exophthalmos of the
ized to the conjunctiva of a common pet psittacine left eye was diagnosed by postmortem examination
bird, the cockatiel. The unifying presentation with caseous endophthalmitis from mycobacterio-
reported here has been commonly recognized by sis.35 In a recent retrospective study of mycobac-
pathologists but not sufficiently discussed in the teriosis in psittacine birds, ocular lesions were
literature.21 identified in only 4 of 123 cases. Lesions consisted
Mycobacteriosis in psittacine birds often affects of swelling of the eyelids and conjunctiva, thick-
the liver, spleen and intestines.3,30 However, ocular ening of the third eyelid, and nodules in the bulbar
lesions do occasionally occur. Reports in the conjunctiva and third eyelid.30LAMB ET AL—MYCOBACTERIAL CONJUNCTIVITIS IN COCKATIELS 255 Figure 2. Granulomatous conjunctivitis identified in a cockatiel that was evaluated in this retrospective study. Open arrow points to a multinucleated giant cell within the granuloma surrounded by fibrous connective tissue and histiocytic inflammation (hematoxylin and eosin; bar ¼ 50 lm). Other differential disease diagnoses for the infection of M genavense and M avium.30 In a previously noted ocular signs reported for myco- separate case report on pet birds, M genavense was bacteriosis include mycoplasmosis, chlamydiosis, responsible for 30.9% of mycobacterium cases, and Pasteurellosis, poxvirus, trauma, and postorbital M avium was only responsible for 12.7%.39 These masses. There are few studies on ocular lesions in studies further corroborate the findings in this birds, with most reports being performed in review, wherein M genavense was identified in 25 of raptors, in which trauma has been identified as 26 cases, and M avium was identified in only 1 case. the cause for up to 90% of ocular lesions.38 Treatment of avian mycobacteriosis is both Many species within the Mycobacterium genus controversial and complicated. Some authors can affect birds. Originally, it was believed that recommend euthanasia and cite numerous motives. most cases were from M avium-intracellulare One reason is therapeutic drugs need to be present complex. With improvements in molecular analysis in tissues at correct concentrations and locations. and culture techniques, M genavense has been Unfortunately, pharmacokinetic studies to deter- found to be a more common causative agent, and mine if these parameters are achieved have not numerous avian case reports have been presented been performed in birds. Other concerns regarding on this species.16,18,19,30,39–44 In a retrospective 20- treatment for avian mycobacteriosis is that the year survey of companion birds, of 24 cases where infected avian patient may be shedding organisms, mycobacteriosis was identified, 23 were from M exposing other birds.2,23 Mycobacterium organisms genavense.18 A separate study, where PCR testing have the potential to be zoonotic, therefore, young, was performed on tissues of 22 psittacine birds, elderly, and immunocompromised people may be revealed M genavense to be responsible for 19 cases more at risk of possible infection. Moreover, of mycobacteriosis, whereas M avium was only studies have indicated differences in drug suscep- identified in 2. One case was found to have a dual tibility for different mycobacterium species that
256 JOURNAL OF AVIAN MEDICINE AND SURGERY Figure 3. Positive Fite acid-fast staining in the conjunctiva of a cockatiel that was evaluated in this retrospective study. Open arrow points to acid-fast bacilli within a granuloma in a conjunctival biopsy sample (bar ¼ 50 lm). may lead to a poor response to therapy.45 Drug mycobacterium’s propensity to mutate rapidly and resistances, a prolonged course of treatment, develop antibiotic resistance. The assumption is treatment compliance by the owner, and difficulties that when using an antibiotic cocktail, the myco- in drug administration are other notable reasons bacteria that are present may be resistant or for not treating avian mycobacteriosis and recom- develop resistance during treatment to one of the mending euthanasia.5 Four cases in this retrospec- medications but is less likely to be resistant or tive study were euthanatized. An additional 10 develop resistance to all of the prescribed drugs.5,22 cases were lost to follow-up. It is unknown whether Previous cases have reported successful mycobac- these cases were euthanatized, died, or received teriosis management with a combination of rifa- treatment at other veterinary facilities. b ut i n , e t h a m bu t o l , c l a r i t h r o m y c i n , a n d For those who decide to treat, it is important to enrofloxacin treatment for 1 year.46,47 Other cases note that no set guidelines for treatment exist in have effectively treated avian mycobacteriosis with avian patients, as they do for humans. Therefore, isoniazid, rifampin, and ethambutol.48 Treatment dosing regimens have been extrapolated from lengths are variable and have ranged from 1 to 18 human medicine and previous avian case reports. months or more. In an ideal situation, treatment When humans are treated for mycobacteriosis, it is length should extend several months beyond the standard to prescribe a combination of 3 or 4 last positive biopsy or culture.10,22 antibiotic drugs. The reasoning behind the antibi- The patients in this report were prescribed otic cocktail approach can be explained by the different drugs to treat avian mycobacteriosis. All
LAMB ET AL—MYCOBACTERIAL CONJUNCTIVITIS IN COCKATIELS 257 26 patients had a biopsied tissue sample submitted meloxicam. For the 2 birds that were prescribed for histopathologic evaluation to diagnose myco- treatment on an as-needed basis, both were bacteriosis definitively, but because of the small receiving ofloxacin topically, and 1 of the 2 size of the patient, this also functioned as an individuals also was administered topical flurbip- excisional biopsy that removed the diseased tissue rofen. With the wide variation in treatment in its entirety in most cases. It cannot be regimens for avian mycobacteriosis and limited determined whether the biopsy completely re- patient size, conclusions cannot be determined moved all the diseased tissue microscopically regarding the best treatment option for this disease because complete postmortem histologic evalua- in cockatiels. tion of each patient was not available. In the 2 One of the limitations of this report is that only cases where this information was available, the the conjunctiva was evaluated for mycobacterial patients had an original biopsy to diagnose the lesions in all but 2 individuals. One case had a full disease and then a full histopathologic evaluation postmortem examination performed when it died 2 after death. Both patients did have lesions in the weeks after a definitive diagnosis of mycobacterial conjunctiva noted on postmortem examination; conjunctivitis was obtained through the histopath- therefore, the diseased tissue was not completely ologic evaluation of tissue collected from a removed during the biopsy procedure. Because of conjunctival biopsy. In this case, granulomas were the retrospective nature of this report, further found in the adrenal gland, intestines, and air sacs, information on whether complete removal of the in addition to the conjunctiva. Moreover, this diseased tissue during the surgical procedure was patient was being treated with topical tobramycin achieved, with and without additional medical at the time of its death. A second patient was management, cannot be determined. euthanatized within a few weeks of diagnosis. It Seventeen patients received medical manage- too had mycobacterial granulomas in the adrenal ment that included topical, oral, and injectable glands and liver. It would have been ideal to have treatments, in addition to a conjunctival biopsy. other organs evaluated for mycobacteria infection Topical antibiotic therapy included terramycin, in all patients; however, the retrospective nature of tobramycin, ofloxacin, ciprofloxacin, gentocin, and this report prevents further evaluation; therefore, bacitracin, neomycin, and polymyxin with and mycobacterial lesions in other organs from the without dexamethasone. Oral antibiotic treatment cases not examined could not be ruled out. Future included enrofloxacin, ethambutol, rifampin, iso- studies should be performed to assess other organs niazide, and ciprofloxacin. Doxycycline was the for mycobacterial lesions when a cockatiel patient only injectable antibiotic used. Nonsteroidal anti- is diagnosed with mycobacterial conjunctivitis. inflammatory medications were used in a few No attempt was made in this retrospective study patients and included oral meloxicam or topical to correlate the histologic appearance of the flurbiprofen or ketorolac. Sixteen of 26 cases had conjunctival biopsies to any prognostic factors. follow-up information available. Of the 4 patients The techniques used to collect the biopsy samples who were euthanatized, 2 had medical treatments varied between cases, times differed from when the in addition to a conjunctival biopsy. Of the 4 lesion was first observed by the owners, and patients that died within 2 months of diagnosis, all different treatments were prescribed for the cases were receiving topical antibiotic therapy, with 1 before biopsy collection, all of which might patient also receiving an injectable antibiotic drug. account for minor variations in the interpretation Of the 3 that died 2 to 3 years after diagnosis, 1 of the histology of the biopsy samples. One sample patient had the conjunctival biopsy, 1 received with more heterophilic inflammation was suspect- topical antibiotic therapy and oral meloxicam as ed to be associated with self-inflicted trauma to the needed, and 1 was prescribed rifampin, enroflox- enlarging conjunctival mass. Not all samples acin, and ethambutol for 6 months. included the conjunctival mucosa, so it is not Of the 5 birds alive at the time of this writing, 1 possible to provide more information on ulcerative was not receiving any treatment, 2 were being lesions. Topical treatments applied by the owners treated with topical medication when an erythem- or as directed by the veterinarians are believed to atous conjunctiva was noted by the owner, and 2 have altered the inflammatory response in some were actively being treated with either oral or cases with corticosteroid and antimicrobial medi- topical antibiotic therapy. Of the 2 actively being cations. treated, 1 was prescribed oral rifampin, ethambu- Mycobacteriosis identified as a conjunctival tol, and ciprofloxacin, and the other was receiving mass in cockatiel patients is an underreported but gentamicin sulfate topical eye drops and oral apparent clinical problem that practitioners should
258 JOURNAL OF AVIAN MEDICINE AND SURGERY
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