Two Cases of Mycobacteriosis in Psittacine Birds
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CASE REPORT Two Cases of Mycobacteriosis in Psittacine Birds C. RIDDELL AND D.R. ATKINSON Department of Veterinary Pathology, Western College of Veterinary Medicine, Saskatoon, Saskatchewan S7N 0 WO (Riddell) and Box 102, Kirkton, Ontario NOK IKO (Atkinson) Summary Two cases of mycobacteriosis in individual psittacine birds from two separate small aviaries are described. The lesions consisted of infiltration of organs with large macrophages, con- taining numerous acidfast organisms. There was no caseation or encapsula- tion of the lesions. No microbiological studies were conducted as mycobacte- riosis was not suspected at the time of necropsy. Resume Deux cas de mycobacteriose, chez des psittacides Cet article decrit deux cas de myco- bacteriose, chez autant de psittacides qui provenaient de deux petites volieres distinctes. Les lesions consis- taient en une infiltration de divers organes par des macrophages volumi- neux et riches en microorganismes acido-resistants; elles ne presentaient ni caseification ni encapsulation. Les auteurs n'effectuerent pas d'examen bacteriologique, parce qu'ils ne soup- connaient pas la possibilite d'une mycobacteriose, lorsqu'ils effectuerent la necropsie de ces oiseaux. Introduction Mycobacteriosis has been reported in many species of domestic, captive and free living birds (6,9,14). The most commonly reported expression of infection in birds has been nodular encapsulated lesions with a caseous centre and containing acid-fast orga- nisms (5, 6,8,12,13). These lesions are commonly called tuberculosis. Another less commonly reported expression of mycobacterial infection in birds has been focal or massive infil- tration of tissues with histiocytes con- taining acid-fast organisms, but with no caseation or encapsulation (2,5,10,11). The present report des- cribes mycobacteriosis of the latter less common type in two psittacine birds from separate small aviaries. History Case A was a budgerigar (Melopsit- tacus undulatus) from a small aviary in which up to 30 budgerigars were kept at any one time for teaching and research purposes at the Western Col- lege of Veterinary Medicine. The aviary consisted of a large flight cage and was stocked initially in October, 1978 with eight birds from a commer- cial source. Since that date the aviary has had a closed population with no new introductions from outside. Mor- tality in the aviary has been very low. One of the original birds died with large amounts of blood on feathers around the mouth in March 1979 and another, the subject of the present report, was found dead in June, 1979. Both birds were necropsied and tissues collected for histology. Some nestlings died in April, 1979 and in October, 1980 as the result of cannibalism. No other birds have died until November 1980. Five birds, progeny of the origi- nal breeders, have been killed for research and teaching purposes at var- ious times and tissues collected for his- tology. No evidence of infectious dis- ease has been found in these young birds. Case B was a dwarf parrot (Broto- gerisjugularis) kept in a small private collection of five parrots which had been acquired over a period of three years. All had been owned by the pres- ent owner for at least nine months. The bird was noticed to lose weight in spite of a good appetite. It became weak and died in September, 1980, when it was submitted for laboratory examina- tion; An African grey parrot (Psittacus erithacus) from the same collection was noticed to bleed from the mouth approximately two months later. The bird died in November, 1980 following another episode of hemorrhage and was submitted for laboratory exami- nation. Tissues were collected for his- tology from both these birds. Subse- quent to a diagnosis of mycobacteriosis in the first bird, fecal samples from the remaining birds in the collection were examined for acid-fast organisms and cultured for mycobacterial organisms with negative results. Pathology The only gross lesion noted in the budgerigar (Case A) was patchy, dark red discoloration of the lungs. On microscopic examination of tissues, lesions were found in the lungs, liver and intestine. In the lungs several ter- tiary bronchi were filled with large foamy macrophages (Figure 1). Small foci of similar macrophages were found throughout the liver where they were surrounded by large numbers of heterophils and lesser numbers of mononuclear cells (Figure 2). A few discrete foci of similar macrophages were found in the lamina propria of the small intestine. The use of the Ziehl-Neelsen stain demonstrated that the macrophages in the intestine and liver contained large numbers of acid- fast organisms. Some macrophages at the edge of the affected bronchi also contained acid-fast organisms. The tongue of the other budgerigar which died with blood on feathers around the mouth had a necrotic tip. On micro- scopic examination the necrotic tissue contained large masses of red blood cells, while a diffuse infiltration of lymphoid cells and macrophages involved the muscles of the tongue. No other lesions were found in this bird and no acid-fast organisms could be found in the lesion in the tongue using the Ziehl-Neelsen stain. Can. vet. J. 22: 145-147 (May 1981) 145
Transcript of Two Cases of Mycobacteriosis in Psittacine Birds
CASE REPORT
Two Cases of Mycobacteriosis in Psittacine Birds
C. RIDDELL AND D.R. ATKINSON
Department of Veterinary Pathology, Western College of Veterinary Medicine,Saskatoon, Saskatchewan S7N 0 WO (Riddell) and Box 102, Kirkton, Ontario NOK IKO (Atkinson)
SummaryTwo cases of mycobacteriosis in
individual psittacine birds from twoseparate small aviaries are described.The lesions consisted of infiltration oforgans with large macrophages, con-taining numerous acidfast organisms.There was no caseation or encapsula-tion ofthe lesions. No microbiologicalstudies were conducted as mycobacte-riosis was not suspected at the time ofnecropsy.
ResumeDeux cas de mycobacteriose, chez despsittacides
Cet article decrit deux cas de myco-bacteriose, chez autant de psittacidesqui provenaient de deux petitesvolieres distinctes. Les lesions consis-taient en une infiltration de diversorganes par des macrophages volumi-neux et riches en microorganismesacido-resistants; elles ne presentaientni caseification ni encapsulation. Lesauteurs n'effectuerent pas d'examenbacteriologique, parce qu'ils ne soup-connaient pas la possibilite d'unemycobacteriose, lorsqu'ils effectuerentla necropsie de ces oiseaux.
IntroductionMycobacteriosis has been reported
in many species of domestic, captiveand free living birds (6,9,14). The mostcommonly reported expression ofinfection in birds has been nodularencapsulated lesions with a caseouscentre and containing acid-fast orga-nisms (5, 6,8,12,13). These lesions arecommonly called tuberculosis.Another less commonly reportedexpression of mycobacterial infectionin birds has been focal or massive infil-tration of tissues with histiocytes con-taining acid-fast organisms, but withno caseation or encapsulation(2,5,10,11). The present report des-
cribes mycobacteriosis ofthe latter lesscommon type in two psittacine birdsfrom separate small aviaries.
HistoryCase A was a budgerigar (Melopsit-
tacus undulatus) from a small aviary inwhich up to 30 budgerigars were keptat any one time for teaching andresearch purposes at the Western Col-lege of Veterinary Medicine. Theaviary consisted of a large flight cageand was stocked initially in October,1978 with eight birds from a commer-cial source. Since that date the aviaryhas had a closed population with nonew introductions from outside. Mor-tality in the aviary has been very low.One of the original birds died withlarge amounts of blood on feathersaround the mouth in March 1979 andanother, the subject of the presentreport, was found dead in June, 1979.Both birds were necropsied and tissuescollected for histology. Some nestlingsdied in April, 1979 and in October,1980 as the result of cannibalism. Noother birds have died until November1980. Five birds, progeny of the origi-nal breeders, have been killed forresearch and teaching purposes at var-ious times and tissues collected for his-tology. No evidence of infectious dis-ease has been found in these youngbirds.Case B was a dwarf parrot (Broto-
gerisjugularis) kept in a small privatecollection of five parrots which hadbeen acquired over a period of threeyears. All had been owned by the pres-ent owner for at least nine months. Thebird was noticed to lose weight in spiteofa good appetite. It became weak anddied in September, 1980, when it wassubmitted for laboratory examina-tion; An African grey parrot (Psittacuserithacus) from the same collectionwas noticed to bleed from the mouth
approximately two months later. Thebird died in November, 1980 followinganother episode of hemorrhage andwas submitted for laboratory exami-nation. Tissues were collected for his-tology from both these birds. Subse-quent to a diagnosis of mycobacteriosisin the first bird, fecal samples from theremaining birds in the collection wereexamined for acid-fast organisms andcultured for mycobacterial organismswith negative results.
PathologyThe only gross lesion noted in the
budgerigar (Case A) was patchy, darkred discoloration of the lungs. Onmicroscopic examination of tissues,lesions were found in the lungs, liverand intestine. In the lungs several ter-tiary bronchi were filled with largefoamy macrophages (Figure 1). Smallfoci of similar macrophages werefound throughout the liver where theywere surrounded by large numbers ofheterophils and lesser numbers ofmononuclear cells (Figure 2). A fewdiscrete foci of similar macrophageswere found in the lamina propria ofthe small intestine. The use of theZiehl-Neelsen stain demonstrated thatthe macrophages in the intestine andliver contained large numbers of acid-fast organisms. Some macrophages atthe edge of the affected bronchi alsocontained acid-fast organisms. Thetongue of the other budgerigar whichdied with blood on feathers around themouth had a necrotic tip. On micro-scopic examination the necrotic tissuecontained large masses of red bloodcells, while a diffuse infiltration oflymphoid cells and macrophagesinvolved the muscles of the tongue. Noother lesions were found in this birdand no acid-fast organisms could befound in the lesion in the tongue usingthe Ziehl-Neelsen stain.
Can. vet. J. 22: 145-147 (May 1981) 145
S t:4f~zFIGURE 1. Tertiary bronchus filled by macro-phages in lung of budgerigar (Case A). H & E.X192.
The liver and spleen of the dwarfparrot (Case B) were enlarged and thewall of the intestine appeared thick-ened. A tumor was suspected. Micro-scopic examination of tissues revealedmacrophages with foamy cytoplasm inclusters throughout the liver (Figure3), almost completely filling the spleenand completely filling and thickeningthe lamina propria of the intestine(Figure 4). The macrophages in allorgans were packed with acid-fastorganisms when examined with theZiehl-Neelsen stain. The only signifi-cant gross lesions in the African greyparrot were severe anemia and darktarry material in the proventriculusand gizzard associated with ulcerationof the gizzard close to the junctionwith the proventriculus. Microscopicexamination of tissues provided littleevidence of any pathology except inthe region of ulceration of the gizzardwhere the koilin layers containedmasses of eosinophilic material andcellular debris.
DiscussionThese cases leave several questions
unanswered. It is unfortunate that
FIGURE 2. Small cluster of macrophages sur-rounded by heterophils and mononuclear cellsin liver of budgerigar (Case A). H & E. X480.
microbiological studies were not con-ducted, but as typical tubercles werenot seen on gross necropsy, mycobac-terial infection was not suspected.Psittacine birds, especially the budge-rigar, are reported to be resistant totuberculosis (1,2). This and anotherrecent report (2) indicate that budge-rigars may succumb to mycobacterialinfection. It is questionable if the typeof lesions reported in this paper shouldbe called tuberculosis, hence the use ofthe term mycobacteriosis. It should benoted that other authors (2) have des-cribed such lesions as tuberculosiswithout isolating and identifying thecausative agent. One study (10) inwhich several birds were cultured andthe organism identified indicated thatsuch atypical lesions can be caused byMycobacterium avium serotype 1. Theauthors of that study suggested thatthe "atypical" lesions were either anearly stage of the disease and wouldprogress in time to the more usual tub-ercles or that they resulted from a dif-ference in host response to M. aviumbetween different avian species.Further isolation and identification ofthe organism involved in these atypical
FIGURE 3. Clusters of macrophages in liver ofdwarf parrot (Case B). H & E. X192.
FIGURE 4. Uniform population of macrophagesinfiltrating the lamina propria in intestine ofdwarf parrot (Case B). H & E. X192.
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lesions would be desirable to eliminatethe possibility that such lesions are theresult of infection with a species ofMycobacterium other than M. avium.Such studies would also be helpful forassessing the public health importanceof such lesions in the increasing popu-lation of pet birds in North America.Tuberculosis in parrots may be due toM. tuberculosis or M. bovis. (3,4). Thedisease in parrots due to M. tuberculo-sis is generally superficial, ofteninvolving the skin of the head andadjacent mucous membranes (3,7). Itis tempting to speculate that the-hem-orrhage from the mouth noted in thetwo birds related to the birds withmycobacteriosis might have been dueto a superficial lesion caused by myco-bacteriosis. However, no evidencecould be found to support this theoryand the death of these other birds fromhemorrhage is considered coincidental.
References1. ARNALL. L. Disease of the respiratory sys-
tem. In Diseases of Cage and Aviary Birds.
M.L. Petrak, Editor. pp.262-289. Philadel-phia. Lea & Febiger. 1969.
2. BRITT, J.O., E.B. HOWARD and W.J. ROSSKOPF.Psittacine tuberculosis. Cornell Vet. 70:218-225. 1980.
3. BROUGHTON, E. Tuberculosis caused byMycobacterium avium. Vet. Bull. 39: 457-465. 1969.
4. FELDMAN, W.H. Tuberculosis of Poultry. InDiseases of Poultry. Fourth Edition. H.E.Biester and L.H. Schwarte, editors. pp. 287-315. Ames: Iowa State University Press.1959.
5. FOWLER, M.E. Infectious and zoonotic dis-eases. In Zoo and Wild Animal Medicine.M.E. Fowler, Editor. pp. 367-374. Phila-delphia: W.B. Saunders Co. 1978.
6. GALE, N.B. Tuberculosis. In Infectious andParasitic Diseases of Wild Birds. J.W.Davis, R.C. Anderson, L. Karstad andD.O. Trainer, Editors. pp. 89-94. Ames:Iowa State University Press. 1971.
7. HUTYRA, F., J. MAREK and R. MANNINGER.
Special Pathology and Therapeutics ofDomestic Animals. Volume 1. p. 673. Lon-don: Bailliere, Tindall and Cox. 1938.
8. KEYMER, I.F. Postmortem examination of
pet birds. Mod. vet. Pract. 42: 35-38. 1961.
9. McDIARMID, A. Diseases of free-living wildanimals. FAO Agricultural Studies No. 57.Rome: F.A.O., U.N. 1962.
10. MONTALI, R.K., M. BUSH, C.O. THOEN and E.SMITH. Tuberculosis in captive exotic birds.J. Am. vet. med. Ass. 169: 920-927. 1976.
11. RATCLIFFE, H.L. Report Penrose Res. Lab.Philadelphia Zoo. 1960. cited by Gale, N.B.Tuberculosis. In Infectious and ParasiticDiseases of Wild Birds. J.W. Davis, R.C.Anderson, L. Karstad and, D.O. Trainer,editors. pp. 89-94. Ames: Iowa State Uni-versity Press. 1971.
12. THOEN, C.O. and A.G. KARLSON. Tuberculo-sis. In Diseases of Poultry. Seventh Edition.M.S. Hofstad, B.W. Calnek, C.F. Helm-boldt, W.M. Reid and H.W. Yoder, Jr.,Editors. pp. 209-244. Ames: Iowa StateUniversity Press. 1978.
13. T-W-FIENNES, R.N. Infectious diseases. InDiseases of Cage and in Aviary Birds. M.L.Petrak, Editor. pp. 357-372. Philadelphia:Lea & Febiger. 1969.
14. WILSON.J.E. Avian tuberculosis: An accountof the disease in poultry, captive birds andwild birds. Br. vet. J. 116: 380-393. 1960.
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