Feline Morbillivirus: Clinical Relevance of a Widespread Endemic Viral Infection of Cats

Feline morbillivirus (FeMV) was first isolated in 2012 from stray cats in Hong Kong. It has been found in association with tubulointerstitial nephritis (TIN), the most common cause of feline chronic kidney disease (CKD). However, viral host spectrum and virus tropism go beyond the domestic cat and kidney tissues. The viral genetic diversity of FeMV is extensive, but it is not known if this is clinically relevant. Urine and kidney tissues have been widely tested in attempts to confirm associations between FeMV infection and renal disease, but samples from both healthy and sick cats can test positive and some cross-sectional studies have not found associations between FeMV infection and CKD. There is also evidence for acute kidney injury following infection with FeMV. The results of prevalence studies differ greatly depending on the population tested and methodologies used for detection, but worldwide distribution of FeMV has been shown. Experimental studies have confirmed previous field observations that higher viral loads are present in the urine compared to other tissues, and renal TIN lesions associated with FeMV antigen have been demonstrated, alongside virus lymphotropism and viraemia-associated lymphopenia. Longitudinal field studies have revealed persistent viral shedding in urine, although infection can be cleared spontaneously.

Naturally Acquired Mouse Kidney Parvovirus Infection Produces a Persistent Interstitial Nephritis in Immunocompetent Laboratory Mice

Mouse kidney parvovirus (MKPV), also known as murine chapparvovirus (MuCPV), is an emerging, highly infectious agent that has been isolated from laboratory and wild mouse populations. In immunocompromised mice, MKPV produces severe chronic interstitial nephropathy and renal failure within 4 to 5 months of infection. However, the course of disease, severity of histologic lesions, and viral shedding are uncertain for immunocompetent mice. We evaluated MKPV infections in CD-1 and Swiss Webster mice, 2 immunocompetent stocks of mice. MKPV-positive CD-1 mice (n = 30) were identified at approximately 8 weeks of age by fecal PCR (polymerase chain reaction) and were subsequently housed individually for clinical observation and diagnostic sampling. Cage swabs, fecal pellets, urine, and blood were evaluated by PCR at 100 and 128 days following the initial positive test, which identified that 28 of 30 were persistently infected and 24 of these were viremic at 100 days. Histologic lesions associated with MKPV in CD-1 (n = 31) and Swiss mice (n = 11) included lymphoplasmacytic tubulointerstitial nephritis with tubular degeneration. Inclusion bodies were rare; however, intralesional MKPV mRNA was consistently detected via in situ hybridization within tubular epithelial cells of the renal cortex and within collecting duct lumina. In immunocompetent CD-1 mice, MKPV infection resulted in persistent shedding of virus for up to 10 months and a mild tubulointerstitial nephritis, raising concerns that this virus could produce study variations in immunocompetent models. Intranuclear inclusions were not a consistent feature of MKPV infection in immunocompetent mice.

Histopathological kidney alterations in rats naturally infected with Leptospira

INTRODUCTION

Histopathological changes by Leptospira in naturally infected rodent reservoirs have been poorly described.

OBJECTIVE

The aim of the current study is to describe renal histopathology associated with leptospirosis infection of naturally infected rodents captured in the urban area of the city of Medellin, Colombia.

MATERIALS AND METHODS

We performed hematoxilin-eosin (H-E) on kidney samples collected from 254 captured rodents. The positive samples were processed by Warthin Starry (W-S) staining and PCR-LipL 32.

RESULTS

Fifty one rodent kidneys showed H-E histopathological changes that consisted of inflammatory infiltrate with lympho-plasmocitary cells and histiocytes. We performed W-S staining and PCR-LipL 32 to 67 kidney samples, including the 51 that had shown detectable changes by H-E and 16 (8%) of 203 rodents with negative results. Eight of the samples that tested positive for H-E (15.7%) were also positive for W-S staining. All negative for H-E were also negative for W-S staining. Of the W-S positive samples also tested for culture only three tested positive for both. Additionally, 47 (92.1%) samples positive for H-E were positive for PCR; while eleven of the 16 (68.8%) negative for H-E were positive for PCR. The samples positive for PCR were subsequently tested for culture and 11 (23.4%) were positive. Seven samples were positive for PCR and W-S and three were positive for PCR, W-S and culture. All of the PCR-LipL 32 fragments were sequenced and showed specific amplicons for L. interrogans .

CONCLUSIONS

The Leptospira infection was confirmed in all of the animals tested. The only histological kidney lesion attributable to leptospiral infection in the reservoir was interstitial nephritis.

Tubulointerstitial nephritis causes decreased renal expression and urinary excretion of cauxin, a major urinary protein of the domestic cat

Cauxin, a member of mammalian carboxylesterases (EC 3.1.1.1), is excreted as a major urinary protein in the domestic cat. Urinary cauxin is derived from the kidney proximal straight tubules. Here, we report changes in the renal expression and urinary excretion of cauxin in cats with tubulointerstitial nephritis (TIN). Immunohistochemistry using anti-cauxin antibody showed fewer cauxin-positive tubules in 15 TIN cases than in normal animals. In areas with tubulointerstitial damage, fibroblasts and inflammatory cells replaced renal tubules, and cauxin-positive tubules consequently disappeared. Urine was analysed in six of the 15 cases. In the two cases with mild tubulointerstitial changes, urinary cauxin was detected using SDS-PAGE with Coomassie staining. In the four cases with severe tubulointerstitial changes, urinary cauxin was below the detection limit using Western blotting. These results indicate that the renal expression and urinary excretion of cauxin decrease with the progression of TIN in cats.

Pathological and aetiological studies of multifocal interstitial nephritis in wasted pigs at slaughter

Multifocal interstitial nephritis in pigs has been associated with several infectious agents. The objective of the present study was to investigate several different potential infectious agents associated with "white-spotted" kidneys in pigs suffering from wasting at slaughter (aged 6-8 months). Twenty-nine case kidneys (with a "white-spotted" gross appearance) classified into 3 macroscopic lesional grades, and 15 control kidneys (lacking gross lesions), were obtained from a pig abattoir. Laboratory analyses to detect potential associations with the aforementioned pathological condition with Leptospira spp., porcine circovirus type 2 (PCV2), porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus (PRRSV), and bacteria, were carried out. Microscopically, interstitial nephritis with a lymphofollicular inflammatory pattern (follicular nephritis) was observed in both case and control kidneys, with a higher frequency seen in the former ones. No leptospires were identified, although antibodies to the Pomona and Bratislava serovars were detected. Some pyogenic bacteria were also isolated from both case and control kidneys. PCV2 nucleic acid was only detected in 1 case kidney. PRRSV antigen was not found in any tested sample. Some pigs were tested positive for PPV by serology. Apparently, none of the studied agents were specifically associated as being the potential cause of the renal lesions in the studied wasted pigs. The fact that these chronic lesions may have been the consequence of a previous infection with one of these studied microorganisms, or more, and eventually with other non-tested infectious agents during the growing-finishing period, cannot be ruled out.

Interstitial nephritis in cats inoculated with Crandell Rees feline kidney cell lysates

Parenteral administration of Crandell Rees feline kidney (CRFK) cell lysates or feline herpesvirus 1, calicivirus, and panleukopenia virus-containing vaccines (FVRCP) grown on CRFK cells induces antibodies against CRFK cells. These antibodies also react with feline renal cell extracts. The purpose of this study was to determine whether interstitial nephritis would be detected in cats that were immunologically sensitized with CRFK lysates, boosted with CRFK lysates, and then biopsied 2 weeks after the booster. Cats (2 per group) were immunologically sensitized against CRFK lysates by administering 10 microg, 50 microg, or 50 microg plus alum 13 times (12 times in the first 50 weeks) over 2 years. Two cats were inoculated three times, 4 weeks apart with an FVRCP vaccine for intranasal administration as kittens, boosted 50 and 102 weeks later, and then renal biopsies taken 2 weeks after the last booster. Neither of the cats vaccinated with the FVRCP for intranasal administration had detectable renal inflammation. One cat in each of the three CRFK lysate sensitization groups had lymphocytic-plasmacytic interstitial nephritis.

Detection of maedi-visna virus in the kidneys of naturally infected sheep

Infections with maedi-visna virus (MVV) cause progressive inflammation in different organs, mainly the lung, mammary gland, brain and joints. The aim of the present study was to investigate whether the kidney represents a viral target in natural MVV infection. For this, kidney samples from 13 sheep naturally infected with MVV were examined by histology, polymerase chain reaction (PCR), and immunohistochemistry. The kidneys of nine animals showed membranoproliferative glomerulonephritis and interstitial nephritis. The inflammatory infiltrate consisted of lymphocytes, plasma cells and macrophages. Interestingly, lymphoid follicles resembling those known to occur in other MVV-infected tissues were observed. Lung tissue from the same animals had typical MVV lesions, such as lymphofollicular hyperplasia and interstitial pneumonia. Maedi-visna proviral DNA sequences were detected in renal and lung tissue samples from these nine sheep by PCR, and the specificity of the amplified products was further verified by DNA sequencing. Moreover, MVV-specific immunohistochemistry revealed viral antigen in affected kidneys and lungs. These results suggest that the kidney may be a common target in natural MVV infection, and raise the issue of the role of this organ in the disease.

Characterization of a novel virus causing a lethal disease in carp and koi

Since 1998 a lethal disease of carp and ornamental koi (Cyprinus carpio) has afflicted fisheries in North America, Europe, and Asia, causing severe economic losses to the fish farming industry. This review summarizes the isolation and identification of the disease-causing agent and describes the currently known molecular characteristics of this newly isolated virus, distinguishing it from other known large DNA viruses. In addition, we summarize the clinical and histopathological manifestations of the disease. Providing information on the immune response to this virus and evaluating the available means of diagnosis and protection should help to reduce the damage induced by this disease. This review does not discuss the economic aspects of the disease or the debate on whether the disease should be registered; both of these issues were recently reviewed in detail (O. L. M. Haenen, K. Way, S. M. Bergmann, and E. Ariel, Bull. Eur. Assoc. Fish Pathol. 24:293-307, 2004; D. Pokorova, T. Vesely, V. Piackova, S. Reschova, and J. Hulova, Vet. Med. Czech. 50:139-147, 2005).

Detection of carp interstitial nephritis and gill necrosis virus in fish droppings

Carp interstitial nephritis and gill necrosis virus (CNGV) is an unclassified large DNA virus that morphologically resembles members of the Herpesviridae but contains a large (ca. approximately 280-kbp) linear double-stranded DNA. This virus has also been named koi herpesvirus, koi herpes-like virus, and cyprinid herpesvirus 3. CNGV is the cause of a lethal disease that afflicts common carp and koi. By using immunohistochemistry, molecular analysis, and electron microscopy we previously demonstrated that this virus is present mainly in the intestine and kidney of infected fish. Based on these observations, we postulated that viruses and/or viral components may appear in droppings of infected carp. Here we report that (i) by using PCR we demonstrated that fish droppings contain viral DNA, (ii) fish droppings contain viral antigens which are useful for CNGV diagnosis, and (iii) fish droppings contain active virus which can infect cultured common carp brain cells and induce the disease in naïve fish following inoculation. Thus, our findings show that CNGV can be identified by using droppings without taking biopsies or killing fish and that infectious CNGV is present in the stools of sick fish. The possibility that fish droppings preserve viable CNGV during the nonpermissive seasons is discussed.

Chemical typing of porcine systemic amyloid as AA-amyloid

Systemic AA amyloidosis is frequently reported in a wide variety of domestic and wild animal species. Porcine amyloidosis is rare and the amyloid has not been typed chemically thus far. In the present study, we have extracted porcine amyloid from formalin-fixed tissue sections. By subsequent amino acid sequencing, an N-terminal fragment was obtained identifying porcine systemic amyloid as AA amyloid. The N-terminal sequence had a great homology to bovine and ovine SAA1, suggesting that pig AA amyloid is derived from the systemic isoform of SAA. It is argued that the low incidence of amyloidosis in pigs is not likely to be attributed to unique features of porcine amyloid precursor protein. Elucidation of the basis for the high apparent resistance of pigs against amyloidosis may yield important clues for treatment and prevention of amyloidosis in other species. This is the first report on chemical identification of porcine amyloid.

Retrospective evaluation of renal disease in captive black howler monkeys (Alouatta caraya)

Six of 15 (40%) inactive medical records of adult black howler monkeys (Alouatta caraya) at one zoological institution included either a pre- or postmortem diagnosis of renal disease. In these six cases, significantly abnormal hematologic and serum chemistry values were reported at onset of azotemia, onset of clinical signs, and at euthanasia. Average age of onset of azotemia was 14.8 +/- 2.9 yr, with clinical signs of disease noted at 17 +/- 4.7 yr. In four of the cases (66.6%), azotemia was documented earlier than the onset of clinical signs of renal disease. Average duration of clinical disease was 2.83 +/- 1.6 yr, with an average age at euthanasia of 18 +/- 4.7 yr. Chronic tubulointerstitial nephritis with secondary glomerular sclerosis was present in all cases. Thirteen of an additional 20 institutions in the United States that have held Alouatta caraya responded to a survey for prevalence of renal disease. These institutions showed a lower prevalence (15.1%) of renal disease in complete, inactive records, a higher prevalence of glomerulonephritis, and similar significant clinicopathologic values.

Pathogenesis of acute viral disease induced in fish by carp interstitial nephritis and gill necrosis virus

A lethal disease of koi and common carp (species Cyprinus carpio) has afflicted many fish farms worldwide since 1998, causing severe financial losses. Morbidity and mortality are restricted to common carp and koi and appear in spring and autumn, when water temperatures are 18 to 28 degrees C. We have isolated the virus causing the disease from sick fish, propagated it in koi fin cell culture, and shown that virus from a single clone causes lethal disease in carp and koi upon infection. Intraperitoneal virus injection or bathing the fish in virus-containing water kills 85 to 100% of the fish within 7 to 21 days. This virus is similar to the previously reported koi herpesvirus; however, it has characteristics inconsistent with the herpesvirus family, and thus we have called it carp interstitial nephritis and gill necrosis virus. We examined the pathobiology of this disease in carp by using immunohistochemistry and PCR. We found large amounts of the virus in the kidneys of sick fish and smaller amounts in liver and brain. A rapid increase in the viral load in the kidneys was detected by using both immunofluorescence and semiquantitative PCR. Histological analyses of fish at various times after infection revealed signs of interstitial nephritis as early as 2 days postinfection, which increased in severity up to 10 days postinfection. There was severe gill disease evidenced by loss of villi with accompanying inflammation in the gill rakers. Minimal focal inflammation was noted in livers and brains. This report describes the etiology and pathology of a recently described viral agent in fish.

Nephropathogenesis of chickens experimentally infected with various strains of infectious bronchitis virus

Four-day-old specific-pathogen-free chickens were inoculated by eyedrop with four different strains (Gray, JMK, CV56b, and Wolgemuth) of infectious bronchitis virus (IBV). Birds were monitored clinically and euthanatized at 1, 4, 7, and 14 days postinfection and tissues were collected for virus isolation, histopathologic examination, in situ hybridization (ISH), and immunohistochemistry (IHC). Clinical disease was severe in chickens infected with Wolgemuth, but no overt disease was observed with the other strains. Virus was isolated from the kidneys of chickens infected with the Gray-, CV56b-, and Wolgemuth-strains of IBV. Histologically, interstitial nephritis was evident in chickens infected with these same 3 strains. However, viral nucleic acid and antigen were detected only with Wolgemuth-infected kidneys by ISH and IHC. These results indicate that the pathological changes in kidneys from chickens infected with Gray and CV56b may not have resulted from the cytolytic action of the virus.

Histopathologic patterns of nephropathy in naturally acquired canine visceral leishmaniasis

Although the nephropathy of visceral leishmaniasis (VL) is known both in humans and dogs, histopathologic alterations have not been thoroughly studied. We examined renal alterations in 55 dogs with naturally acquired VL compared with five noninfected dogs from an endemic area in northeastern Brazil. Glomerulonephritis was found in 55 dogs, interstitial alterations in 53 dogs, and tubular changes in 43 dogs with VL. The glomerular alterations found were minor glomerular abnormalities (n = 8, 14.5%), focal segmental glomerulosclerosis (n = 10, 18.2%), mesangial proliferative glomerulonephritis (n = 17, 32.7%), membranoproliferative glomerulonephritis, (n = 18, 30.9%), crescentic glomerulonephritis (n = 1, 1.8%), and chronic glomerulonephritis (n = 1, 1.8%). Morphometric and ultrastructural studies complemented the analysis. The five control animals exhibited no glomerular alterations. The glomerular lesions were related to functional alterations. Considering that the alterations of canine and human nephropathy in VL are very similar, the data obtained in this study constitute an important contribution to the understanding of canine and human VL nephropathy.

Characterization of renal damage in canine leptospirosis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting of the urinary proteins

Canine leptospirosis is a zoonotic disease that can cause interstitial nephritis. As a consequence of the renal damage, proteinuria may occur. To determine the urine protein pattern in the disease we performed sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) on the urine from 10 dogs with leptospirosis and 20 healthy dogs. Western blotting analysis of the urine samples with antibodies against canine IgG and IgA was also performed to identify these immunoglobulins in the urine. Urine electrophoresis showed three new bands in the dogs suffering from leptospirosis. Only two of the dogs with leptospirosis showed detectable concentrations of IgG and IgA in urine, while a third animal showed IgG alone. The study showed a 36.7% increase in the excretion of low molecular weight proteins in dogs with leptospirosis but almost no change in the high molecular weight protein pattern. These results, together with the low number of animal with detectable concentrations of IgG and IgA in the urine, support the view that canine leptospirosis is characterized by interstitial nephritis.

Leptospira in slaughtered fattening pigs in southern Vietnam: presence of the bacteria in the kidneys and association with morphological findings

One kidney was collected from each of 32 fattening pigs at an abattoir in southern Vietnam in 2001 in order to demonstrate infecting Leptospira serovar and to associate renal macro- and microscopic findings with the presence of renal leptospires. Leptospires were demonstrated in 22 (69%) of the investigated kidneys by immunofluorescence. Multifocal interstitial nephritis (MFIN) and gross renal lesions (white spots) were each demonstrated in 24 (75%) kidneys. Leptospira interrogans serovar bratislava was isolated from one kidney. There was no association between presence of leptospires and MFIN (P=0.19), respectively and white spots (P=0.98), respectively. These data suggest that Leptospira infection is common among fattening pigs in the study area and that these animals may be considered as an occupational human health hazard. It is also suggested that the presence of white spots is an unreliable indicator of the presence of renal leptospires.

Polycystic and chronic kidney disease in a young degu (Octodon degus)

A young adult (approximately 20 months), 125 g, female degu (Octodon degus) was housed with a male degu for approximately 1.2 years as a breeding pair. The female was multiparous and had weaned its third litter 2 weeks earlier. The degu was reported to the veterinary service for bloody vaginal discharge and a hunched, thin appearance of 1 day's duration. On physical examination, it exhibited cachexia, molting, slight matting of the hair around the eyes, and moderate dehydration. Hematology results included anemia and leukopenia with lymphocytopenia. Biochemical abnormalities included severe azotemia and phosphatemia. Urine specific gravity was 1.016. The condition of this animal prohibited its continued use in the breeding colony, so it was submitted for necropsy. On gross examination, the left kidney measured 10 x 15 mm, had an irregular surface, and was pale and mildly enlarged, consistent with compensatory hypertrophy. The right kidney was small (5 x 8 mm) and cystic. Both adrenal glands appeared mildly enlarged. Histologically, the left kidney had multiple regions with chronic, diffuse interstitial nephritis, and the right kidney was polycystic. There was mild, focal, cortical nodular hyperplasia in the adrenal glands. In the uterus, there was unilateral, locally extensive necrosis of the endometrium. The clinical chemistry results and histopathology findings are supportive of a diagnosis of renal failure secondary to chronic nephritis and polycystic kidney disease. The etiology of the nephritis is unknown. Polycystic kidney disease can be congenital or hereditary in other rodents.

Susceptibility of three genetic lines of chicks to infection with a nephropathogenic T strain of avian infectious bronchitis virus

Mortality rates were compared in three genetic lines of specific pathogen-free chicks inoculated with one of two doses of a nephropathogenic strain of avian infectious bronchitis (IB) virus. The mortality rates were influenced primarily by the chick strain, but also by age and dose of virus. Chicks of the inbred S line were highly susceptible. After inoculation with a low dose of virus at 2 and 4 weeks of age, mortality was 90 and 45%, respectively. Chicks of the HWL non-inbred line were also susceptible, with mortality rates after inoculation at 2 and 4 weeks of age of 70 and 25%, respectively. Chicks of the inbred W line were resistant and non-significant mortality of 10% occurred only in 2-week-old chicks inoculated with a high dose of virus. Viral distribution in tissues of susceptible S and resistant W chicks did not differ, and virus was present in the trachea, lung and kidney of chicks from both lines throughout the acute phase (between days 3 and 7) of infection. Viral titres in the trachea and kidney in susceptible S chicks were slightly but not significantly higher than in the other chicks during the acute phase of infection. Histopathological assessment indicated an earlier onset of a regenerative phase in the trachea of W chicks than in S chicks. S chicks, in contrast to W chicks, showed no signs of renal regeneration. Additionally, the kidneys of S chicks differed from those of W chicks in showing more severe nephritis, more tubular necrosis and less heterophil infiltration and lymphocytic response throughout the acute phase of infection. The results indicate that chicken lines may differ greatly in their susceptibility to fatal IB nephritis and that resistance is likely to be under the control of immune responses to viral infection.

A study of "white spotted kidneys" in cattle

A study was performed at an abattoir in Australia, in an attempt to correlate focal chronic interstitial nephritis (FCIN) producing the so-called "white spotted kidney", with Leptospira spp. and other pathogens in cattle. Samples of kidneys, urine and blood were collected immediately after slaughter from 46 two-year-old heifers, and 72 cows and bulls with gross lesions consistent with FCIN. The same samples were also collected from nine heifers and 12 cows with no gross kidney lesions. Aqueous humour was also collected from the eye of 17 of the adult animals. The sera were processed by a microscopic agglutination test for leptospira antibodies, while all the other samples were cultured for Leptospira spp. and also processed for routine aerobic and anaerobic culture for other pathogens. Sub-samples from all the kidneys were fixed in 10% buffered formalin and processed histologically. Antibody titers of 1:400 or higher for Lepstospira borgpeterseni serovar hardjo were found in six adult animals with FCIN and in one adult animal with no gross kidney changes, while antibody titers of 1:400 to L. borgpeterseni serovar tarassovi were found in only one animal with FCIN. L. borgpeterseni serovar hardjo was isolated from the urine and kidney of one adult animal and from the urine of another adult animal, both with FCIN. No pathogens were isolated from any of the other samples. The histological lesions were consistent in most cases with FCIN. The results suggest that neither Leptospira spp. nor active infection by other bacteria are associated with the so-called "white spotted kidneys".

Infectious agents identified in pigs with multifocal interstitial nephritis at slaughter

One kidney was taken from each of 100 pigs at slaughter; 50 had gross lesions of multifocal interstitial nephritis and 50 had no gross lesions. Forty-nine of the affected kidneys had lesions that were characterised by the presence of either a few randomly distributed or numerous widely disseminated pale foci, 1 to 3 mm in diameter, on the cortical surface (white-dotted kidneys). Microscopically, these focal inflammatory lesions often had a distinct lymphofollicular pattern (follicular nephritis). Lesions of chronic vasculitis were observed in 21 of the affected kidneys. Histologically, the control kidneys had only small and sparse inflammatory foci. Standard bacterial cultures of kidneys of both groups were not significant, and cultures for the isolation of leptospires were all negative. Virological examination of the kidney homogenates by PCR did not reveal any porcine reproductive and respiratory syndrome virus and only a few cases were positive for the porcine circovirus type 1. However, porcine parvovirus (PPV) and porcine circovirus type 2 (PCV-2) were detected in many kidneys of both groups but in a significantly higher proportion of the kidneys with interstitial nephritis. There was a significant association between the lesions and the presence of PPV and PCV-2 with odds ratios of 7.5 (P<0.0001) and 3.4 (P=0.0074), respectively, and the odds ratio increased to 22.7 (P<0.0001) when both viruses were identified in the same kidney. However, a subsample of kidneys taken from both groups were negative by immunohistochemistry for the presence of PPV and PCV-2 antigens.

An improved immunohistochemical diagnostic technique for canine leptospirosis using antileptospiral antibodies on renal tissue

The purpose of this study was to compare the immunoreactivity in canine renal tissues stained with antisera specific for 3 leptospiral antigens and those processed with traditional staining methods. In addition, immunoglobulin staining was done on tissues with immunoreactivity to leptospiral antigens. Formalin-fixed renal sections from 12 dogs with chronic interstitial nephritis suspected or proven to have leptospirosis (6 dogs with silver-stained leptospires and 6 dogs in which silver-stained leptospires were not detected) were used. Antibodies consisted of a monoclonal antibody to Leptospira kirschneri serovar grippotyphosa lipopolysaccharide (LPS) and 2 polyclonal antibodies to outer membrane proteins, including OmpL1, a leptospiral porin, and LipL41, an outer membrane lipoprotein. The murine monoclonal antisera against LPS (F71C2-1) had the most abundant and consistent immunoreactivity. Immunoreactive areas were present in 6 of 6 sections positive by silver staining and included extracellular granular debris in intertubular areas, debris in macrophages, organisms in tubular lumina, and cytoplasmic granules in tubular epithelia. Antisera with specificity for the outer membrane proteins OmpL1 and LipL41 detected only intact organisms in tubular lumina. Immunoreactivity to OmpL1 (polyclonal 338) occurred in 4 of 5 sections positive by silver staining, but immunoreactivity to LipL41 (polyclonal 813) occurred in only 1 of 6 silver-positive sections. Each of the kidney sections in which leptospiral antigens were detected by immunohistochemistry also was positive by silver staining. Sections negative by silver staining were also negative by immunostaining. Although immunohistochemistry did not enhance sensitivity, amplification of signal by secondary antibody and hematoxylin counterstaining improved the ease of diagnosis and allowed better evaluation of tissue morphology than did silver staining methods. IgG was the most abundant immunoglobulin. IgG immunoreactivity occurred predominantly in plasma cells within interstitial infiltrates. Interstitial infiltrates contained abundant immunoreactivity to LPS, but immunoreactivity to OmpL1 and LipL41 was not noted.

Chronic tubulointerstitial nephropathy in six okapis (Okapia johnstoni)

Renal tubular atrophy with conical and medullary interstitial fibrosis with severe thickening of the basement membranes of atrophic tubules was found in six okapis (Okapia johnstoni). Focal glomerular atrophy, probably secondary to ischemic collapse of the glomerular capillary tuft, was also observed. Although the etiologies and pathogeneses of these nephropathies are unclear, primary damage of the tubular epithelium appears to be the most likely cause, and toxicity from ingested plant material, possibly willow (Salix sp.), is a possibility.

The prevalence of interstitial nephritis and leptospirosis in 283 raccoons (Procyon lotor) from 5 different sites in the United States

A retrospective histopathological study was carried out on tissues of 283 raccoons from 5 different geographical locations for presence of interstitial nephritis and renal leptospirosis. Results of this study indicate that although interstitial nephritis was common in raccoons from all locations, the presence of renal leptospiral spirochetes was not.

Immunoperoxidase and histopathological examinations of leptospiral nephritis in cattle

This study was designed to investigate the role of leptospirae in interstitial nephritis. Sixty-eight white-spotted kidneys and 30 grossly normal kidneys from slaughtered cattle were examined histologically and immunohistochemically for the presence of Leptospira interrogans antigens. The presence of L. interrogans antigens was found in 21 of 68 white-spotted kidneys and in four of 30 normal kidneys. In conclusion, the detected incidence of infection with L. interrogans was not high, but there was a relationship between the presence of interstitial nephritis and leptospiral antigens.

Expression of alpha-smooth muscle actin and fibronectin in tubulointerstitial lesions of cats with chronic renal failure

OBJECTIVE

To examine renal expression of alpha-smooth muscle actin (alpha-SMA) and fibronectin in cats with tubulointerstitial nephritis (TIN) for use in predicting progression to renal fibrosis.

ANIMALS

19 cats with TIN and 9 cats without nephritis.

PROCEDURE

Serum creatinine and BUN concentrations were measured. Indices for glomerular extra-cellular matrix (ECM), tubular injury (TI), and fibronectin were determined in renal specimens to quantify the extent of injury and fibrotic lesions. Expression of alpha-SMA in renal tissue was immunohistochemically detected, and correlations were evaluated between the alpha-SMA index and other histologic and clinical variables.

RESULTS

The alpha-SMA index in tubulointerstitial areas (1.63 +/- 0.78) was significantly higher in cats with TIN, especially in the periglomerular and peritubular areas, than in cats without nephritis (0.20 +/- 0.14). The alpha-SMA index was significantly associated with the TI index (r2 = 0.70), fibronectin index (r2 = 0.95), BUN concentration (r = 0.64), and serum creatinine concentration () = 0.66). Of special interest was that interstitial alpha-SMA expression appeared evident in the kidneys at an early stage of TIN, prior to the onset of ECM deposition.

CONCLUSION AND CLINICAL RELEVANCE

Analysis of results of histologic and clinical examinations revealed that interstitial alpha-SMA expression may have clinical importance and may be a useful early histologic marker for development of chronic renal failure in cats. An immunohistochemical examination for fibrogenic molecules (such as alpha-SMA expression) may provide fundamental information on the pathogenesis of early-stage renal disease and aid clinical management of cats with chronic renal failure, including TIN.

Genetic mapping of a locus associated with bovine chronic interstitial nephritis to chromosome 1

Chronic interstitial nephritis with diffuse zonal fibrosis (CINF) occurs in Japanese Black cattle (Wagyu) as an autosomal recessive disorder leading to death prior to puberty, first six months or a year of life. We performed a genome-wide scan using microsatellite markers in a Wagyu pedigree segregating for CINF and mapped the CINF locus to bovine chromosome 1. CINF was closest to microsatellites BM9019 and INRA49 (Z score = 12.0; P < 3.4 x 10(-10)).

Histopathological and immunohistochemical studies on cetaceans found stranded on the coast of Italy between 1990 and 1997

Detailed histopathological and immunohistochemical studies were carried out on 24 cetaceans, 17 of which were striped dolphins (Stenella coeruleoalba), four bottlenose dolphins (Tursiops truncatus) and three Risso's dolphins (Grampus griseus), all found stranded on the Italian coast between 1990 and 1997. The most frequently detected lesions were chronic pneumonia (73.7% of the examined lungs), focal chronic pancreatitis (71.4%), non-purulent encephalitis (50%), chronic hepatitis (42.1%), and chronic focal interstitial nephritis (31.2%). The skin and the subcutaneous panniculus were often (33.3%) affected by parasitic diseases (Phyllobothrium delphini and Pennella sp.). An appreciable percentage of animals showed lymphoid depletion in their lymphatic organs (47.2%), as well as a high rate of parasitic infestations in their alimentary tracts (25%).

Probable toxicosis in cattle in Israel caused by the oak Quercus calliprinos

A probable outbreak of oak (Quercus calliprinos) toxicosis in a herd of beef cattle--heifers and first-calving cows--grazing in the Judean foothills of Israel is described. Toxicosis probably occurred because of the consumption of oak leaves and buds during a period of pasture scarcity without any feed supplementation. A progressive syndrome of wasting, dullness, anorexia, polyuria, nephrosis, constipation and recumbency, culminating in death, was seen. A high mortality rate of 83% (38/46 animals) was noted. The clinical-pathological findings revealed increases in blood urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatine kinase (CK), lactate dehydrogenase (LDH) and inorganic phosphorus. Decreases were found in alkaline phosphatase (ALP), total serum protein, albumin (ALB), triglyceride (TG), calcium (Ca), magnesium (Mg), sodium (Na) and chloride (CI). The main pathological findings were severe nephrosis, chronic interstitial nephritis, and occasional intestinal ulceration. On the basis of epidemiology, clinical signs, clinical-pathological and pathological findings and renal histology, a tentative diagnosis of oak toxicosis was made.

Proteinuric hypertension in a pregnant baboon: was this pre-eclampsia?

We report the results of investigating a pregnant baboon that developed hypertension, proteinuria, and oedema in late gestation. Although the clinical presentation suggested a diagnosis of pre-eclampsia, the evolution of her clinical signs and results of a renal biopsy performed 3 weeks after delivery suggested that glomerulonephritis was the underlying disease.

Leptospirosis in raccoons in Quebec: 2 case reports and seroprevalence in a recreational area

Raccoons may represent a source of leptospires for humans and domestic animals. We describe a case of severe interstitial nephritis associated with the serovar bratislava of Leptospira interrogans (1st report in wildlife), and the seroprevalence to 4 leptospire serovars in a recreational area in Quebec.

Equine viral arteritis in newborn foals: clinical, pathological, serological, microbiological and immunohistochemical observations

Clinical, pathological, immunohistochemical, serological and microbiological findings are described for 2 geographically and temporally distinct equine arteritis virus (EAV) epidemics in newborn foals. Outbreak A occurred at a commercial Standardbred breeding facility; Outbreak B began in a group of research animals. Clinical signs were severe and primarily referable to the respiratory tract. Fever and leucopenia and/or thrombocytopenia were observed in foals surviving for more than 24 h. The most common gross pathological findings were limited to the respiratory tract. Common histopathological findings included interstitial pneumonia, lymphocytic arteritis and periarteritis with fibrinoid necrosis of the tunica media. Renal tubular necrosis was noted in 2 foals. Immunoperoxidase histochemistry combined with virus isolation was diagnostic in all cases.

Morphologic, immunohistochemical, and ultrastructural characterization of a distinctive renal lesion in dogs putatively associated with Borrelia burgdorferi infection: 49 cases (1987-1992)

A distinctive renal lesion consisting of glomerulonephritis, diffuse tubular necrosis with regeneration, and interstitial inflammation was found in 49 biopsy/necropsy cases obtained from 1987 to 1992. This lesion is manifested clinically as a rapidly progressive glomerular disease that was uniformly fatal. Immune-mediated membranoproliferative glomerulonephritis predominated (43/49, 88%). Membranous glomerulonephritis (5/49, 10%) and amyloidosis (1/49, 2%) were also noted. Subendothelial deposits, IgG, IgM, and C3 were present along glomerular basement membranes. IgA was absent. The exact cause of the tubular necrosis is unknown. Affected dogs were significantly younger (5.6 +/- 2.6 years) than dogs with other forms of glomerulonephritis (7.1 +/- 3.6 years) and amyloidosis (7.8 +/- 3.5 years) both in the studied population for the same period and in the reported canine population. Labrador and Golden retrievers were 6.4 and 4.9 times more likely, respectively, to develop this lesion. This is the first report of a breed predilection for spontaneous canine glomerulonephritis. Previous reports have associated this lesion with Borrelia burgdorferi exposure. All dogs in this study were from Lyme disease-endemic areas. Of 18 dogs serologically tested, all were positive for exposure. Silver stain examination of kidneys revealed rare spirochetes, suggesting that the presence of spirochetes in the kidney is apparently unrelated to lesion development. The role of vaccination in development of the renal lesion is undetermined. The association of this histologically and clinically unique lesion, Lyme nephritis, with Borrelia burgdorferi infection is significant because it is the only fatal form of canine Lyme borreliosis.

Relationship between inflammatory hepatic disease and inflammatory bowel disease, pancreatitis, and nephritis in cats

OBJECTIVE

To determine whether cats with inflammatory hepatic disease had concurrent inflammatory bowel disease (IBD), pancreatitis, or chronic interstitial nephritis.

DESIGN

Prospective case series.

SAMPLE POPULATION

78 tissue sections of liver, intestine, pancreas, and kidney from cats that had previous necropsy examinations at the teaching hospital.

PROCEDURE

We reviewed histologic sections of liver, intestine, pancreas, and kidney from cats that had previous necropsy examinations and determined the prevalence of lymphocytic portal hepatitis, cholangiohepatitis, IBD, pancreatitis, and chronic interstitial nephritis, and the relationship among them.

RESULTS

36 cats had lymphocytic portal hepatitis, 18 had cholangiohepatitis, and 24 did not have inflammatory hepatic disease. The prevalence of IBD (10/36; 28%) and pancreatitis (5/36; 14%) in cats with lymphocytic portal hepatitis was not significantly different from cats without inflammatory hepatic disease. The prevalence of IBD (15/18; 83%) and pancreatitis (9/18; 50%) was greater (P < 0.05) for cats with cholangiohepatitis, compared with cats without inflammatory hepatic disease. Thirty-nine percent of cats (7/18) with cholangiohepatitis had IBD and pancreatitis. Evidence of IBD in association with cholangiohepatitis was characterized by infiltration of lymphocytes and plasma cells into the lamina propria; however, neutrophilic infiltrates also were found in 6 of 15 (40%) cats with cholangiohepatitis. Pancreatitis was mild in all cats.

CLINICAL IMPLICATIONS

Cats with a diagnosis of cholangiohepatitis should be evaluated for IBD and pancreatitis.

Expression of class II major histocompatibility complex molecules in renal tubular epithelial cells of canine kidneys affected with tubulointerstitial nephritis

Class II major histocompatibility complex (MHC) products are important molecules on various antigen-presenting cells and induce a T cell-specific immune response. The distribution of class II MHC molecules in the normal canine kidneys of dogs with tubulointerstitial nephritis was investigated by using a sensitive immunocytochemical method. In the normal canine kidney, class II MHC molecules were detected in interstitial 'dendritic' cells. In cases of tubulointerstitial nephritis, however, the expression of class II MHC molecules extended to other renal elements such as the epithelial cells of cortical and medullary tubules and, in some cases, the endothelial cells of peritubular capillaries. The tubular expression of class II MHC molecules was enhanced in dogs with higher levels of proteinuria. The results suggest that heavy proteinuria may be one triggering factor in canine tubulointerstitial damage, probably mediated by the reabsorption of filtered cytokines and immunogenic peptides which induce tubular epithelial cells to behave as immune accessory cells.

Resolution of a left ureteral stone using electrohydraulic lithotripsy in a thoroughbred colt

A 3-year-old Thoroughbred colt was presented for evaluation of azotemia and anorexia. Physical examination revealed a ureterolith in the left ureter, approximately 10 cm from the bladder, which was thought to obstruct urine flow by approximately 90% when viewed cystoscopically. Ultrasonographic examination of both kidneys revealed indistinct corticomedullary junctions, and the right kidney was more hyperechoic. A percutaneous biopsy of the right kidney revealed chronic interstitial nephritis with marked interstitial medullary fibrosis. Medical therapy consisting of IV fluids, sodium chloride PO, and ammonium chloride PO was initiated. Ureteroscopic electrohydraulic lithotripsy via a perineal urethrostomy was used to successfully remove the stone. Klebsiella oxytoca, which responded to oral enrofloxacin therapy, was cultured from the urine after surgery. Azotemia resolved and the horse resumed training.

Leptospira interrogans serovar sejroe infection in a group of laboratory dogs

Interstitial nephritis was seen histologically in 19 (59%) out of 32 pure-breed beagle dogs (16 males and 16 females) subjected to standard safety tests. In these animals no clinical abnormalities were observed and all the tested parameters (haematology, biochemistry and urine analysis) were within the normal ranges. Leptospiral antibody titres ranging from 1 : 100 to 1 : 6400, against a serovar (hardjo) belonging to the Sejroe serogroup, were detected by the microscopic agglutination test (MAT) in the serum of the 19 dogs with interstitial nephritis. All animals without renal lesions were seronegative. Leptospiral antigen was detected immunohistochemically in the kidneys of 4 dogs; leptospires were detected in Warthin-Starry stained sections of one dog. Leptospires were isolated from the kidneys of 3 of the 4 dogs examined by bacterial culture. The isolated strains were typed as serovar sejroe by restriction endonuclease digestion and Southern blot hybridization analysis of their DNA. It was concluded that Leptospira interrogans serovar sejroe, was responsible for an asymptomatic chronic renal infection which was widespread in this group of laboratory dogs.

Tubular vimentin metaplasia in canine nephropathies

The expression of the intermediate filament vimentin was examined immunocytochemically in 17 cases of histologically confirmed primary canine nephropathy, and compared with its expression in normal canine kidney. In normal renal tissue, the expression of vimentin was restricted to glomerular elements, but in all cases of chronic interstitial nephritis it extended to the cortical tubular epithelia, and was correlated with the degree of tubulo-interstitial damage. Three of four cases of renal cell carcinoma had vimentin reactivity in neoplastic cells. In only one case of familial renal disease was vimentin expressed in scattered epithelial cells of the cortical tubules.

A new familial glomerulonephropathy in Bernese mountain dogs

Between 1989 and 1992, 22 Bernese mountain dogs (18 females and four males) aged between two and seven years, which had been suffering for some weeks from weight loss, anorexia, apathy, vomiting, polydipsia and polyuria, were examined. All of them had high blood urea nitrogen and serum creatinine concentrations, and many had hyperphosphataemia, hypercholesterolaemia, hypoproteinaemia and nonregenerative anaemia. All the dogs had very high protein: creatinine ratios in the urine, and macroproteinuria was identified by sodium dodecyl sulphate gel electrophoresis. The immunofluorescent titres against Borrelia burgdorferi, measured in 19 of the dogs, ranged between 256 and 32,768. In all cases, membrano-proliferative glomerulonephritis with concomitant interstitial nephritis was diagnosed. From an analysis of the dogs' pedigree it was concluded that the glomerulonephritis of these Bernese mountain dogs was inherited as an autosomal recessive trait and that its expression was influenced by a second gene locus with a sex-linked dominance exchange.

Mesangioproliferative glomerulonephritis in mink with encephalitozoonosis

Renal specimens from 6 mink with encephalitozoonosis were studied by light and electron microscopy and immunohistochemistry. The glomeruli of affected kidneys had a mesangioproliferative glomerulonephritis which was characterized by an increase in mesangial cells and matrix in most glomeruli. Some glomeruli were partially or completely sclerosed. There were protein or granular casts in the cortical and medullary tubules. Interstitial nephritis, vasculitis and tubular cysts were found. Electron microscopy demonstrated extensive matrix and increased cellularity in the mesangial areas. Glomeruli showed segmentally thickened or wrinkled capillary basement membranes. Electron dense deposits were found in the glomerular basement membranes and mesangium. Peroxidase-anti-peroxidase immunohistochemistry demonstrated that IgG and IgM positive material was present as granular deposits in the glomerular basement membrane and occasionally in the mesangium.

Acute tubulo-interstitial nephritis in a dog after halothane anaesthesia and administration of flunixin meglumine and trimethoprim-sulphadiazine

Acute tubulo-interstitial nephritis was diagnosed post mortem when a dog died four days after surgery for a femoral head resection. Possible causative factors associated with halothane anaesthesia, flunixin meglumine analgesia and prophylactic antibiotic therapy with trimethoprim-sulphadiazine are discussed. It is concluded that death was due to renal failure associated with tubulo-interstitial nephritis as a result of a combination of ischaemic and toxic events.

Renal microangiography and correlated histopathological observation of cows with nephropathy

Seven Holstein-Friesian cows showing chronic nephropathy were studied by renal microangiography and its correlated histopathology. In cases of pyelonephritis associated with severe pathological lesions such as thickening of arterial walls, narrowing of the arterial and arteriolar lumen, and interstitial inflammation and abscess formation, patchy loss of the peritubular capillary plexus from the cortex to the medulla was clearly demonstrated by microangiography. Interlobular arteries were tortuous and attenuated or truncated. Opacification in the vasa rectae and interstitial capillaries was increased. Extensive non-perfused regions could be detected in the cortex. In cases of mild interstitial nephritis and moderate pyelonephritis, microangiography showed focal changes in the renal vasculature. Microangiography is thus shown to clearly demonstrate changes in the renal vasculature corresponding to the severity of the histopathological lesions.

Encephalitozoon infection in a still-born foal

A stud Clydesdale foal was still-born near full term. Macroscopic examination revealed a normal placenta, pulmonary atelectasis and faint white mottling of the kidneys. Microscopically there was severe lymphoplasmacytic interstitial nephritis. Numerous organisms resembling Encephalitozoon cuniculi were present in the affected kidneys. The organisms occurred in the areas of inflammation as well as in the renal glomeruli and intracellular cysts in the renal tubular epithelial cells and exhibited Gram positive staining. Ultrastructurally the organisms possessed a polar vacuole and a spiral filament typical of Microsporidia. The organisms were not detected in sections of the other organs examined.

The role of the common vole (Microtus arvalis) in the epidemiology of bovine infection with Leptospira interrogans serovar hardjo

Control of leptospirosis in cattle depends on the presence of other possible maintenance hosts, with which cattle may have contact. Twenty-seven common voles (Microtus arvalis) were trapped on a dairy farm where the cattle were infected with Leptospira interrogans serovar hardjo (hardjo). In the sera of 11 voles, titres greater than or equal to 100 against serogroup Grippotyphosa were measured with the microscopical agglutination test (MAT). From 8 of these 11 voles, which also showed interstitial lymphoplasmacellular nephritis, Leptospira interrogans serovar grippotyphosa was isolated. We found no evidence that the common vole is a maintenance host for hardjo in this biotope.

Differences in the induction of urate deposition of specific-pathogen-free chicks inoculated with avian nephritis virus passaged by five different methods

The G-4260 strain of avian nephritis virus (ANV) was passaged using five different methods as follows: method 1, passage three times in chorioallantoic membrane (CAM) of 11-day-old embryonated eggs (CAM3); method 2, passage twice in CAM and further passage once in yolk sac (YS) of 6-day-old embryonated eggs (CAM2-YS1); method 3, passage 11 times in CAM (CAM11); method 4, passage 10 times in CAM and further passage twice in YS (CAM10-YS2); method 5, passage as in Method 4 and then passage three times in chicken kidney cell culture (CAM10-YS2-CK3). CAM11 and CAM10-YS2 were each inoculated orally into 25 one-day-old specific-pathogen-free (SPF) chicks. Seven chicks in the CAM11-inoculated group and six chicks in the CAM10-YS2-inoculated group died or were killed because they were moribund; all had either nephrosis or urate deposition. CAM3, CAM2-YS1, CAM10-YS2, and CAM10-YS2-CK3 were each inoculated intraperitoneally into 15 one-day-old SPF chicks. No chicks inoculated with CAM3 or CAM2-YS1 died, but wo chicks inoculated with CAM10-YS2 and three inoculated with CAM10-YS2-CK3 died with urate deposition. At 14 postinoculation, plasma urate values of the CAM10-YS2- and CAM10-YS2-CK3-inoculated chicks were significantly higher than those of CAM3- and CAM2-YS1-inoculated chicks and control chicks (P less than 0.01). However, interstitial nephritis was observed in most of the ANV-inoculated birds.

[Chronic interstitial nephritis in cattle with cardiomyopathy]

We tried to characterize the chronic interstitial nephritis as it occurs in bovine cardiomyopathy (CMP). For that reason conventional analysis methods were applied to urine of healthy and CMP-diseased cattle. With all the sick animals used for this study a nephritis of the mentioned type was diagnosed pathologically. By discriminant analysis of our data we were able to show, that the chronic interstitial nephritis due to CMP was best described by the variables protein (precipitation by heat), renal epithelial cells and leukocytes. In 73% of all the affected cattle one or more variables were changed pathologically to a minor to moderate degree. In the remaining 27% they were within the normal range. A possible microhematuria was secondary. Using identification analysis all the healthy animals and 69% of the diseased ones were made out correctly. As a consequence of this study we conclude, that further methods are necessary in order to recognize the different forms of nephritis more reliably.

Avian nephritis virus infection of chicks: virology, pathology, and serology

Avian nephritis virus (ANV), G-4260 strain, was inoculated orally into 1-day-old specific-pathogen-free chicks of the line 15I for virological, pathological, and serological study of the ANV infection of chicks. The virus titer and incidence of appearance of fluorescent antigens in the kidneys were highest at 4 days postinoculation (PI) and decreased gradually. The degeneration of proximal tubules was the principal pathological change in kidneys of chicks at 4 days PI, and interstitial nephritis was the principal pathological change in kidneys of chicks from 6 to 14 days PI. Moreover, gouty nodules were apparent in the kidneys of more than half of the chicks at 10 days PI. The plasma urate value of infected chicks was clearly higher than that of control chicks, reaching a maximum at 10 days PI, then gradually decreasing. The serum antibody was detected from 4 days PI and increased gradually. The chicks affected with visceral urate deposits or urate deposits in the digitated joints showed high plasma urate values (more than 100 mg/dl).