Klossiella Cobayae Associated with Chronic Interstitial Nephritis in Guinea Pigs
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Stand. 1. Lab. Anim. Sci‘ 141 firg. nr. 1 1987 Klossiella cobayae associated With Chronic Interstitial Nephritis in Guinea Pigs by R. E. Feimtein and C. Rehbinder The National Veterinary Institute, Box 7073, 8-750 07 Uppsala INTRODUCTION urine. When ingested by a new host, the The protozoan parasites Klossiella belong sporozoites excyst in the intestinal lumen. to the Class Telosporea, subclass Coccidia, Once they reach the capillaries they in- order Eucoccidiae, Suborder Adeleina, fa- vade endothelial cells, starting a new mily Klossiellidae (Honigber et al. 1964). cycle. Members of this family have been de- We communicate herein the finding of scribed in guinea pigs (K.cobayae), mice K. cobayae in convertionally kept, clinical- (K. muris), horses (K. equi), (Vetterlz’ng ly healthy guinea pigs submitted for health 1975) and laboratory rats (Shadduck and monitoring at the National Veterinary Pakes 1978). K. cobayae, the kidney coc- Institute, Uppsala, Sweden. cidium of the guinea pig, was earlier considered ubiquitous among guinea pig MATERIAL AND METHODS colonies in various parts of the world, but Animals: Six conventionally kept, female, reports on this parasite are nowadays rare Dunkin-Hartley guinea pigs of body (Boniciu et al. 1957, Manning et al. 1984). weights ranging from 730 g to 1070 g The life cycle of K. cobayae is direct. were selected from the breeding stock of According to Vetterling (1976), the first a research unit, and submitted for health schizogony occurs in the capillary endo- monitoring. After euthanasia by CO2 in- thelial cells of the kidney and other organs. halation, necropsies were immediately per- Mature schizonts contain merozoites that formed. are released into the blood when the host Histology: Samples from different organs cell ruptures. Merozoites could invade were fixed in 10 0/0 buffered formaline other endothelial cells repeating the schi- for 24 hours. After routine histological zogonic phase, or could reach the kidney, processing, the material was embedded in where a second generation schizogony oc- paraffin, cut 4 pm thick sections and curs in the epithelium of the proximal stained with haematoxylin and eosin. Ad- convoluted tubules. Large schizonts con— ditional sections from kidney were stained taining numerous merozoites distend the according to the following methods: Azan, tubular cells, until they rupture. The me— Gram, PAS, and van Gieson. rozoites are released and enter the epi— Parasitology: Routine parasitological exa- thelium of the thick limb of Henle’s loop. mination was performed. Lung samples There gametogony starts. Differentiation were used for detection of antibodies of macro— and microgametes is followed against Toxoplasma gondii and Encepha- by fertilization of the macrogametes. The litozoon amiculi, by means of india—ink resultant zygote undergoes sporogony. The immunoassay (Waller 1977). sporont produces sporoblasts that become sporocysts. Each sporocyst gives rise to RESULTS numerous sporozoites. The host cell mem- Kidney brane ruptures releasing sporulated sporo— Macroscopical examination: Two guinea cysts that leave the kidney carried by the pigs exhibited bilateral granular appear- 25 Scand. J. Lab. Anim, Sci. 14. firg. nr. 1 1987 i5}.' \ Fig. J. Kidney. Schizont containing numerous merozoites, filling the lumen of a proximal convoluted tubule (arrow). H. 8: E. X 1000. ence of the subcapsular surface. Four degeneration and necrosis and areas of guinea pigs did not present any macro— reparative hyperplasia of the epithelium. scopical change. The basal laminae were thick and hyalin- Histopathological examination: Renal mi- ized, and tubular lumina were often filled croscopical changes were present in all of with homogenous strongly PAS positive the guinea pigs, but were more severe and material. Mitotic figures were common, involved larger areas in kidneys with 0b- both in tubular epithelium and in inter— Vious macroscopical lesions. In the ad- stitial fibroblasts. Necrotic tubuli contain— vanced cases, affected areas comprised ing mineralized casts were numerous in about half of the kidney parenchyma. the medullary zone, often located in areas Large schizonts containing numerous me- devoid of inflammatory changes. rozoites, characteristic of K. cobayae, were The glomeruli displayed thick, hyalin- observed in tubular lumina (Fig. 1). The ized, strongly PAS positive Bowman’s number of parasites was low. They were membranes. Severe hypertrophy of the negative for the Gram stain, and neither parietal epithelial linning was occasional- Azan nor PAS stains evidenced a cutic- ly observed (Fig. 2). Few glomeruli were ular structure. The lesions occurred main- atrophic and sclerotic. ly in the cortex. They were severe but The interstitium within affected zones focal. Within affected areas almost all presented marked fibroblastic prolifera- tubuli and glomeruli displayed marked tion and lymphocytic infiltration (Fig. 3). disruption. Constant features were tubular A discrete number of eosinophils was ob- 27 Scand. J. Lab. Anim. Sci. 14. firg. nr. 1 1987 remit Fig. 2. Kidney. Cortical focus of inflammation. Note marked glomerular changes. The parietal layer of Bowman’s capsule exhibits thickened basal lamina (arrow) and hypertrophy of parietal epithelium (arrow head) Atrophic glome- rular capillaries display thickened basal laminae. PAS stain X 400 Fig. 3. Kidney. Focus of chronic interstitial nephritis with mild mononuclear infiltration, fibroblastic proliferation and tubular disruption. PAS stain X 400. 29 Scand. 1. Lab. Anim. Sci. 14. firg. nr. 1 1987 served in glomerular and tubular capil— tively low degree of parasitic infection. laries. Two guinea pigs presented mode— In the present study, stages of K. cobayae rate infiltration of lymphocytes and plas— were not found in the lungs (a systematic ma cells in the renal pelvis. search was not attempted). However, lung changes similar to the ones we observed Lungs were reported by Bonciu et al. (1957) in Macroscopical Changes were not observed. 90 0/9 of the guinea pigs infected by this Histologically, all guinea pigs exhibited a parasite. The lesions were produced by marked perivascular infiltration of mono— parasitic damage to the vascular endo- nuclear leukocytes and a low number of thelium. As the bacteriological and para— eosinophils. Mild focal chronic interstitial sitological studies from lungs and diges— pneumonia was diagnosed in two guinea tive organs were negative for infections pigs. Stages of K.cobayae were not ob— that could induce similar pulmonary served. changes, we conclude that they are most Other visceral organs did not present sig- probably due to extrarenal stages of K. nificant changes. cobayae. Parasitological findings: The nasal cavi— Since infected guinea pigs mainly are ties and the gastrointestinal canal were asymptomatic, the disease usually remains free of parasites. undetected. Guinea pigs are often used The india-ink immunoreaction was nega— for different toxicological studies in which tive both for Toxoplasma gondii and for the kidneys or the lungs are target organs Encephalilozoon cuniculi antibodies. (Hour 1976). Lesions caused by K. cobayac may thus modify experimental results. In— Discussion fection with K. cobayae, even when Schizonts of K. cobayae were diagnosed asymptomatic, is reported to increase the in the kidneys of guinea pigs with lesions sensitivity of guinea pigs to different of focal chronic interstitial nephritis and toxic substances (Bonciu el al. 1957). The chronic pneumonia. role of K. cobayae infection as a source According to Vetterling (1976), the most of misinterpretation of experimental re— readily identifiable and most frequently sults has also been emphasized by von seen stages of K. cobayae are those oc- Kossel (1958) and van Hofman and curring in the kidneys. Stages in other Hdm'chen (1970). locations should be carefully examined Reliable methods for identification of live since they somewhat resemble T. gondii guinea pigs infected with K. cobayae are and E. cuniculi (van Cosscl 1958, Vetter— not available, and the authors are not ling 1976). As the kidneys are a common aware of any treatment. However, it has location for E. cuniculi, a differential been suggested that this parasite could be diagnosis must be made also when renal controlled by reducing the urine cont- stages of K. cobayae are detected. amination of guinea pigs facilities (Vetter- It has been stated that the parasite is ling 1976). Cesarean derivation permits usually nonpathogenic (Flynn 1973), pro- the obtention of guinea pigs free from duces only slight kidney changes (Mam- K.cobayae (Flynn 1973). ning et al. 1984), or that is nonpathogenic The present findings underline that health exept in very heavy infections (Shaddock monitoring including macro- and micro- et al. 1978). However, our findings are in scopical examination of different organs agreement with those of Hofmann and is a mandatory procedure for the identific- Hiz'nic/zen (1970), who observed a patho- ation of health problems affecting experi- genic affect on the kidney, even in a rela- mental animals. 31 Scand. J. Lab. Anim. Sci. 14. Eng. nr. 1 1987 References S/mdduck, ]. A. and S. P. Pakes: Protozoan Bonciu, C., B. Clecner, A. Greceanu 61 A. and metazoan diseases. In Pathology of Mc'z‘rgineanu: Contribution a l’étude de Laboratory Animals, K. Benirschke, F. M. l’infection naturelle des cobayaes avec des Garner and T. C. Jones, Eds. Springer sporozoaires du genre “Klossiella”. Arch. Verlag, Chapter 1978, 17: 1587—1696, Roum. de Pathol.