Septic Embolic Actinobacillosis

Transcription

1 Path. vet. 6: (1969) From the Department of Veterinary Diagnostic Laboratories, College ofveterinary Medicine, University of Minnesota, St. Paul Septic Embolic Actinobacillosis A Report of 2 Cases in New World Monkeys H.W. MOON, D.M. BARNES and J.M. HIGBEE Septic embolic actinobacillosis caused by Actinobacilhs eqzluli (Shigella equirzllis, Shigella uiscosum equi, Bacterium uiscosum equi, Bacillus ncphritidis equi) is common in foals and also occurs in mature solipeds 4* 7, 8. There are several manifestations of A. eyuuli infection in horses: an acute embolic suppurative nephritis or polyarthritis of foals, a fulminating septicemia, and septic abortion. Widespread bacterial emboli and associated microabscesses are characteristic histopathological features of the disease in horses. In addition to solipeds, A. eyuuli has been associated with septicemia in swine and granulomatous arthritis in rabbits 2. 8, 9. We found no report of A. equuli infection in primates. The listing of this organism as the cause of death in 3 primates in a zoo is apparently a typographical error and should refer to solipedse. This report describes a spontaneous disease in new world monkeys associated with A. eyuuli infection. Materials and Methods The subjects of this report were a 6-month-old, male, squirrel monkey (Saimtri sciwezis) and a young male spider monkey (Atelespaniscus) estimated to weigh 0.5 kg. Both died less than 1 week following air shipment from Florida. They were submitted at different times by different owners who bought them for pets. They were depressed on arrival, ate very little, and developed rapidly progressive weakness. Neither monkey was treated. The squirrel monkey vomited and had intermittent diarrhea. Portions of brain, myocardium, liver, spleen, lung, kidney, small intestine, colon, and mesenteric lymph node were fixed in 10% neutral buffered formalin, embedded in paraffin, cut in sections 7p thick, and stained with hematoxylin and eosin. Histological sections from foals with A. equuli infection were studied for comparison.

2 482 lhf 0 0 N / B A R N E S / H I G B E E The bacteriological techniques used were as described by EDWARDS and EWING~. Unfixed heart blood and liver were streaked on glass slides and stained by a Gram s technique. Results Both monkeys died several hours before necropsy but were well preserved. Grossly, there was extensive bilateral renal and adrenal cortical hemorrhage. The spleens were dark and engorged with blood. There were numerous white foci less than 1 mm in diameter scattered throughout the livers. There were subserosal petechial hemorrhages on the small intestine of the squirrel monkey. The lungs of the spider monkey were mottled, scattered dark areas involving several lobules were firm, and there was interstitial emphysema. Smears of heart blood and liver from both monkeys contained numerous small Gram-negative rods. Tentative diagnoses made at the time of necropsy were enteritis with septicemia in the squirrel monkey and pneumonia with septicemia in the spider monkey. The most extensive histological lesions were in the kidneys of both monkeys. These were: numerous large bacterial emboli in the glomerular and intertubular capillaries (Fig. 1, 2), areas of cortical necrosis and hemorrhage interpreted as infarcts, and microabscesses which obliterated many glomeruli (Fig. 2). Focal areas of necrosis associated with bacterial emboli were scattered throughout the livers of both monkeys (Fig. 3), and the lungs of the spider monkey. In addition, there were areas of hemorrhage with alveolar and interstitial emphysema in the lungs of the spider monkey. Widely scattered bacterial emboli were in capillaries and venules of the heart of both monkeys, lungs and mesenteric lymph nodes of the squirrel monkey, and meninges over the cerebrum of the spider monkey. There was little or no reaction in the tissue surrounding emboli in these locations (Fig. 4). Both spleens were congested but contained no embolus. There was diffuse reticuloendothelial hyperplasia, necrosis of lymphcytes, and a light infiltration of neutrophils in germinal centers of the spleen, mesentric lymph nodes, and lymphatic tissue in the colon. Actinobacillus eqccccli was recovered in pure culture on sheep blood agar that was incubated aerobically at 37 C for 24 h following inoculation with tissue from heart, liver, lung, and kidney of both animals. Cultures from both animals produced identical reactions in bacteriological media. The cultures produced acid, but no gas, in 24 h from dextrose, lactose, sucrose, maltose, and mannitol but did not ferment dulcitol, inositol, salicin, or sorbitol. They did not produce urease, indole, or acetylmethylcarbinol, hemolyze sheep red blood cells, or utilize citrate. They produced H2S when tested with lead acetate strips but not when tested in triple sugar iron agar, reduced nitrate, were negative to the methyl red test, and were nonmotile. A culture from the spider monkey was given to a guinea pig subcutaneously. This animal appeared to be normal when killed 2 months later. A culture from each monkey was submitted to the National Communicable Disease Center at Atlanta, Georgia and the identification of A. equuh confirmed.

3 F&. 1. Section of renal cortex from a spider monkey with A. eguuli infection. There are large bacterial emboli in glomeruli and in intertubular capillaries. H&E. Fig. 2. Embolic suppurative glomerulitis in the kidney of a squirrel monkey with A. equuli infection. H&E.

4 Fig. 3. Embolic suppurative hepatitis in a monkey with A. eqctrli infection, H&E. Fig. 4. Bacterial emboli in the lung of a monkey with 4. equdi infection, H&E.

5 Septic Embolic Actinobacillosis 485 Discussion The lesions in these monkeys are indistinguishable from the embolic suppurative hepatitis and nephritis, widespread septic emboli, adrenal cortical hemorrhage, and splenic and lymphatic lesions characteristic of A. equuli infection in horses4, 7, 8. Both monkeys were young and most of these cases in horses occur in foals ; however, during periods of stress, adult horses may develop the diseasel. It is likely that the stress resulting from shipping and relocating predisposed these monkeys to the disease. In contrast to foals, infection with A. equuli is apparently rare in monkeys. The diseases in swine and rabbits29 8 are not characterized by the extensive bacterial emboli which occur in foals and monkeys. A. equuli occurs in the intestinal tract of normal horse+. The organism was not demonstrated in the intestinal tract of these monkeys ; however, the cultural techniques applied to the intestinal contents were inhibitory for A. equuli. In the absence of a demonstrable portal of entry, it is assumed that the initial invasion were from the intestinal tract. The disease in monkeys must be differentiated from shigellosis and pasteurellosis. A. eqdi shares many characteristics with the Sbigella. The following characteristics were useful in differentiating this disease from shigellosis. In contrast to A. equuli, most Shigella do not ferment lactose or sucrose and all are positive to the methyl red test. Sbigella sonnei ferments lactose and sucrose slowly, but A. equuli ferments these sugars in 24 h. Septicemia is uncommon in shigellosis. However, we have examined newborn monkeys that had a septicemia due to S. sonnei and they did not have the bacterial emboli seen in these monkeys infected with A. equuli. Massive and widespread bacterial embolism is a characteristic feature of the septicemic phase of infections with either A. equuli or Pasteurella bemolytica, as well as infections with Hemophilus agni in sheep and a septicemia of cattle caused by a Hemopbilus-like organism7. The disease reported here was differentiated from pasteurellosis on the basis of different reactions in bacteriological media produced by A. equuli and P. bemolytica. Most strains of A. equuli are nonhemolytic but hemolytic have strains been reportedg. There is evidence that A. equuli and Actinobacillus lignieresii should be classified in the same species, although they are currently separated3~ g. Infection with Actinobacillus equuli occurred in a squirrel monkey (Saimiri sciureus) and a spider monkey (Afeles paniscus). The disease in monkeys, characterized by widespread bacterial embolism and embolic suppurative nephritis, was similar to the disease caused by A. equuli in foals. Infektionen mit Actinobacilh equuli traten bei einem Totenkopfchen (J aimiri sciureus) und einem Schwarzen Klammeraffen (Atelespaniscus) auf. Die Erkrankung

6 486 MOON/BARNES/HiGBEE war bei den Affen durch eine ausgedehnte bakterielle Embolie und eine durch die Embolie verursachte eitrige Nephritis gekennzeichnet, und stimmte mit der durch A. equuli bei Fohlen verursachten Erkrankung iiberein. 1. ALD~SY, P. and SUVEGES, T : Megfigyelkk az igislovak pyoseptikaemiijird (Polysepticemia in draught horses). Magyar rillat. Lap, 19: (1964). 2. ARSECULERATNE, S.N.: Actinobacillosis in joints of rabbits. 1. comp. Path. 72: (1962). 3. BREED, R.S.; MURRAY, E.G.D. and SMITH, N.R.: Bergey s Manual of Determinative Bacteriology. 7th ed. (Williams and Wilkins, Baltimore 1957). 4. Du PLESSIS, J.L. : The histo-pathology of Shigella viscosum equi infection in newborn foals. /. sth. afr. vet. med. Ass. 34: (1963). 5. EDWARDS, P.R. and EWING, W.H. : Identification of Enterobacteriaceae. 2nd ed. (Burgess, Minneapolis 1962). 6. IPPEN, R. : Auswertung der bei 1400 Zoo- und Wildtieren (mammalia) erhobenen Zerlegungsbefunde. Zhl. VetMed. 148: (1967). 7. JUBB, K.V.F. and KENNEDY, P.C.: Pathology of Domestic Animals. Vol. 2 (Academic Press, New York 1963). 8. SZBKY, A. : Adatok a lo 6s a sertks Bacterium pyasepticurn okozta megbetegedksknek k6rszovettanihoz (Histology of Bact. vzscosurn equi in horses and pigs). Magyar &at. Lap. 15: (1960). 9. WETMORE, P.W. ; THIEL, J.F. ; HERMAN, Y.F. and HARR, J.R. : Comparison of selected Actznobacillus species with a hemolytic variety of Actinobacillus from irradiated swine. J. infect. D~J. 113: (1963). Author s address: Dr. I-innmu W. MOON, Animal Discase and Parasite Ilescarch Division, National Animal Discssc Laboratory, Amr, iowa (USA).