Serum, milk, and tissue monensin concentrations in cattle with adequate and potentially toxic dietary levels of monensin: pharmacokinetics and diagnostic interpretation.

Used in both beef cattle and dairy cows, monensin can provide many health benefits but can, when unintended overexposures occur, result in adverse effects. Information on serum and tissue concentrations following overexposure and/or overt toxicosis which may aid in diagnostics and clinical outcome is lacking. The aim of this study was to determine concentrations of monensin in biological specimens following oral exposure for 10 days to an approved dose (1 mg/kg) and a higher dose (5 mg/kg) of monensin given daily on a body weight basis to 10 dairy cows. No deaths were reported; cows receiving 5 mg/kg showed early signs of toxicosis including depression, decreased feed intake, and diarrhea after 4 days of exposure. Histopathological findings were minimal in most cows. Pharmacokinetic modeling of the detected serum concentrations for the 1 and 5 mg/kg dose groups determined the Cmax , Tmax, and t1/2λ to be 0.87 and 1.68 ng/mL, 2.0 and 1.0 h, and 1.76 and 2.32 days, respectively. Mixed regression models showed that the dose level and days since last dose were significantly associated with monensin concentrations in all four tissues, and with cardiac troponin levels. The high dose resulted in a significant elevation of monensin in tissues at approximately 4.7 times compared to the monensin concentrations in the tissues of animals from the low-dose group. The cTnI concentrations in the high-dose group were 2.1 times that of cTnI in the low-dose group. Thus, the ability to diagnose monensin overexposure and/or toxicosis will improve from knowledge of biological monensin concentrations from this study.

Diagnostic exercise: High mortality in a flock of chukar partridge chicks (Alectoris chukar) in California.

Mortality of 20% of a flock of 1000 chukar partridge chicks occurred over a 6-week period in Northern California from August to September 2012. Affected birds were 2 to 42 days old and died without premonitory clinical signs or after showing ruffled feathers and anorexia for 24 to 72 hours. Three carcasses were submitted for necropsy, 2 birds had hemorrhagic tracheitis grossly, and all 3 had lymphoplasmacytic and histiocytic myocarditis with myocardial necrosis microscopically. The differential diagnoses and the diagnostic workup to achieve a final diagnosis are discussed. The detection of 2 zoonotic agents in these birds makes this an interesting case from a public health perspective.

Temporal and geographic clustering of polyomavirus-associated olfactory tumors in 10 free-ranging raccoons (Procyon lotor).

Reports of primary nervous system tumors in wild raccoons are extremely rare. Olfactory tumors were diagnosed postmortem in 9 free-ranging raccoons from 4 contiguous counties in California and 1 raccoon from Oregon within a 26-month period between 2010 and 2012. We describe the geographic and temporal features of these 10 cases, including the laboratory diagnostic investigations and the neuropathologic, immunohistochemical, and ultrastructural characteristics of these tumors in the affected animals. All 9 raccoons from California were found within a localized geographic region of the San Francisco Bay Area (within a 44.13-km radius). The tight temporal and geographic clustering and consistent anatomic location in the olfactory system of tumor types not previously described in raccoons (malignant peripheral nerve sheath tumors and undifferentiated sarcomas) strongly suggest either a common cause or a precipitating factor leading to induction or potentiation of neuro-oncogenesis and so prompted an extensive diagnostic investigation to explore possible oncogenic infectious and/or toxic causes. By a consensus polymerase chain reaction strategy, a novel, recently reported polyomavirus called raccoon polyomavirus was identified in all 10 tumors but not in the normal brain tissue from the affected animals, suggesting that the virus might play a role in neuro-oncogenesis. In addition, expression of the viral protein T antigen was detected in all tumors containing the viral sequences. We discuss the potential role of raccoon polyomavirus as an oncogenic virus.

Diagnostic exercise: hemolysis and sudden death in lambs.

Within a 24-hour period, 7 out of 200 three- to four-week-old pastured Katahdin lambs died after showing clinical signs of hemoglobinuria, red-tinged feces, weakness, and recumbency. One of the lambs that was examined clinically before natural death also had abdominal pain, trembling, tachycardia, and severe anemia with a packed cell volume of 4%. Pathologic findings included icterus, hemoglobinuric nephrosis, dark red urine, pulmonary edema, hydrothorax, splenomegaly, and acute centrilobular to midzonal hepatocellular degeneration and necrosis with cholestasis. The differential diagnoses and diagnostic workup to achieve the diagnosis are briefly discussed.

Nematode-associated intramural alimentary nodules in pumas are histologically similar to gastrointestinal eosinophilic sclerosing fibroplasia of domestic cats.

Intramural alimentary nodules in the gastric pylorus and proximal duodenum are a common finding in free-ranging pumas (Puma concolor) in North America, and are often associated with the presence of an indwelling nematode (most commonly Cylicospirura spp.). This study compares the histological, histochemical and immunohistochemical appearance of three proximal gastrointestinal nodules in pumas with four cases of eosinophilic sclerosing fibroplasia in domestic cats. Histologically, the pattern of inflammation and repair was strikingly similar, consisting of lamillated anastomosing trabeculae of dense sclerotic collagen with interspersed inflammatory cells and reactive fibroblasts. The stromal trabeculae were histologically reminiscent of osteoid and were uniformly positive for collagenous protein by Masson's trichrome stain and negative for mineralized osteoid deposits with Von Kossa's stain. Trabecular cells expressed osteonectin, but not osteocalcin immunohistochemically. Collectively, these findings are most consistent with a stroma comprised of dense collagenous trabeculae that resembles, but is distinct, from osteoid. Both the puma and domestic cat lesions demonstrated an eosinophilic inflammatory component; however, eosinophils were present in small numbers in the puma nodules relative to the nodules in domestic cats. These entities likely represent a unique and stereotypic gastrointestinal repair response of felids, given their similar histological, histochemical and immunohistochemical profiles.

Evaluation of the toxicity of Adonis aestivalis in sheep.

To determine the toxicity of Adonis aestivalis (adonis) in sheep, adult Suffolk ewes were administered 1 per cent bodyweight adonis via surgically placed rumen cannulas in an acute, high-dose toxicity study, and 0.2 per cent bodyweight daily in a two-week, low-dose toxicity study. The ewes received cardiac examinations before dosing, 24 and 48 hours after dosing with 1 per cent bodyweight adonis, and after continuous low-dose administration. All the ewes administered adonis had transient sinus arrhythmias after receiving 1 per cent bodyweight adonis. Two of the three ewes had transient reduced fractional shortening after administration with 1 per cent bodyweight adonis; the same two ewes had reduced fractional shortening after the low-dose treatment regimen. No gross or microscopic lesions were seen when the ewes were examined postmortem at the end of the study.

Ronidazole toxicosis in 3 society finches (Lonchura striata).

A group of finches were accidentally overdosed with ronidazole, a 5-nitroimidazole used for treatment of trichomoniasis. Finches developed neurologic signs on the third day of treatment and were euthanized (or died). Three finches were submitted for necropsy. Focal necrosis of the cerebellar nucleus was seen in all 3 birds, as characterized by neuronal necrosis, vacuolation of the neuropil, gemistocytic astrocytosis, hemorrhage, and axonal swelling (spheroids) with demyelination. The liver from 1 finch was analyzed for ronidazole and its metabolite, 2-hydroxymethyl-1-methyl-5-nitroimidazole, by high-performance liquid chromatography-mass spectrometry. Ronidazole was detected in the liver tissue at 2,700 ng/g (wet weight), and 2-hydroxymethyl-1-methyl-5-nitroimidazole was detected at 140 ng/g (wet weight).

Summer pheasant's eye (Adonis aestivalis) poisoning in three horses.

Three horses died as a result of eating grass hay containing summer pheasant's eye (Adonis aestivalis L.), a plant containing cardenolides similar to oleander and foxglove. A 9-year-old thoroughbred gelding, a 20-year-old appaloosa gelding, and a 5-year-old quarter horse gelding initially presented with signs of colic 24-48 hours after first exposure to the hay. Gastrointestinal gaseous distension was the primary finding on clinical examination of all three horses. Two horses became moribund and were euthanatized 1 day after first showing clinical signs, and the third horse was euthanatized after 4 days of medical therapy. Endocardial hemorrhage and gaseous distension of the gastrointestinal tract were the only necropsy findings in the first two horses. On microscopic examination, both horses had scattered foci of mild, acute myocardial necrosis and neutrophilic inflammation associated with endocardial and epicardial hemorrhage. The third horse that survived for 4 days had multifocal to coalescing, irregular foci of acute, subacute, and chronic myocardial degeneration and necrosis. A. aestivalis (pheasant's eye, summer adonis) was identified in the hay. Strophanthidin, the aglycone of several cardenolides present in Adonis spp., was detected by liquid chromatography-mass spectrometry-mass spectrometry in gastrointestinal contents from all three horses. Although Adonis spp. contain cardiac glycosides, cardiac lesions have not previously been described in livestock associated with consumption of adonis, and this is the first report of adonis toxicosis in North America.

Odocoileus hemionus deer adenovirus is related to the members of Atadenovirus genus.

The Odocoileus hemionus deer adenovirus (OdAdV-1) causes systemic and local vasculitis and proves extremely lethal for mule deer. To characterize the virus, part of the genome flanking the fiber gene was cloned and sequenced. The sequence revealed two open-reading frames that mapped to pVIII hexon-associated protein precursor and fiber protein of several other adenoviruses. The highest amino acid homology for pVIII and fiber was found with the members of the proposed Atadenovirus genus: ovine adenovirus isolate 287 (OAdV-287), bovine adenovirus 4 (BAdV-4) and duck adenovirus 1 (DAdV-1). The homology with bovine adenovirus type 3 (BAdV-3) proved low. The E3 region was not found between the gene for pVIII and fiber. These data suggest that OdAdV-1 is a member of the Atadenovirus genus.

Microscopic evidence of adenoviral infection in a muskrat in Illinois.

A wild muskrat (Ondatra zibethicus) found moribund in Illinois (USA) had minimal meningitis and pleuritis, probably of bacterial origin. There were large, basophilic, intranuclear inclusion bodies within scattered enterocytes. The inclusions were microscopically typical of those produced by adenoviruses, and ultrastructurally were intranuclear paracrystalline arrays of virus particles with characteristics of adenoviruses. The significance of the adenovirus infection in this muskrat is unknown.

Characterization of a new adenovirus isolated from black-tailed deer in California.

An adenovirus associated with systemic and localized vascular damage was demonstrated by transmission electron microscopy and immunohistochemistry in a newly recognized epizootic hemorrhagic disease in California black-tailed deer. In this study, we describe the cultural, physicochemical and serological characteristics of a virus isolated from lung using neonatal white-tail deer lung and turbinate cell cultures. The virus had the cultural, morphological and physicochemical characteristics of members of the Adenoviridae family. The virus would not replicate in low passage fetal bovine, caprine or ovine cells. Antiserum to the deer adenovirus, strain D94-2569, neutralized bovine adenovirus type-6 (BAdV-6), BAdV-7, and caprine adenovirus type-1 (GAdV-1). Antiserum to BAdV-6 did not neutralize the deer adenovirus but antiserum to BAdV-7 and GAdV-1 neutralized the deer adenovirus. Cross-neutralization with the other bovine, caprine and ovine adenovirus species was not observed. Restriction endonuclease patterns generated for the deer adenovirus were unique compared to those for the currently recognized bovine, caprine and ovine adenovirus types. Amino acid sequence alignments of the hexon gene from the deer adenovirus strain D94-2569 indicate that it is a member of the proposed new genus (Atadenovirus) of the Adenoviridae family. While closely related antigenically to BAdV-7 and GAdV-1, the deer adenovirus appears sufficiently distinct culturally and molecularly to justify consideration as a new adenovirus type.

Adult cockatiels (Nymphicus hollandicus) metabolically adapt to high protein diets.

To determine the ability of cockatiels (Nymphicus hollandicus), a granivorous avian species, to adapt metabolically to high dietary protein levels, adult males (n = 26) were fed isocaloric diets containing 11, 20, 35 or 70% crude protein (CP) for 11 mo. Throughout the trial, body weight and breast muscle weight were maintained by 11, 20 or 70% CP. The 35% CP diet resulted in significantly greater body weight (P < 0.05) and whole-body lipid content (P < 0.05) compared with the 11% CP diet. The 20% CP diet resulted in greater breast muscle mass compared with 70% CP (P < 0.05). Activity of the amino acid catabolic enzymes alanine aminotransferase, aspartate aminotransferase and arginase as well as the gluconeogenic enzyme phosphoenolpyruvate carboxykinase were significantly increased with 70% CP (P < 0.05). Serum essential amino acids, urea and uric acid were also increased with 70% CP (P < 0.05), but the magnitude of their increase was similar to that found in omnivorous chickens fed a similar diet. There was no evidence of visceral gout, articular gout or renal pathology; however liver lesion severity, and specifically liver lipogranuloma severity, was significantly increased above 11% CP (P < 0.05). We conclude that cockatiels are able to up-regulate enzymes for amino acid catabolism as well as mechanisms for nitrogen excretion in response to high dietary protein levels, and that high dietary protein levels are not associated with kidney dysfunction in this avian species.

Experimental adenovirus hemorrhagic disease in white-tailed deer fawns.

Infection with a newly described endotheliotropic adenovirus was the cause of a 1993 epizootic reminiscent of hemorrhagic disease in California mule deer (Odocoileus hemionus columbianus and O. hemionus hemionus). Pulmonary edema and intestinal luminal hemorrhage, or necrotizing stomatitis associated with systemic or localized vasculitis, respectively, were common lesions seen in animals that died during the epizootic. In order to determine if white-tailed deer (Odocoileus virginianus) also are susceptible to infection and fatal disease with the deer adenovirus, eight white-tailed deer fawns (4- to 6-mo-old) were inoculated with purified deer adenovirus. Four were inoculated intravenously and four were inoculated through the mucous membranes. Seven days post-inoculation, one of the fawns inoculated intravenously died. Pulmonary edema and hemorrhagic enteropathy were associated with pulmonary and intestinal vasculitis with systemic multiorgan distribution of endotheliotropic adenovirus as demonstrated by transmission electron microscopy and immunohistochemistry. Adenovirus was reisolated from lung homogenates of the fawn that died of adenovirus hemorrhagic disease.

Fatal pulmonary edema in white-tailed deer (Odocoileus virginianus) associated with adenovirus infection.

Sporadic sudden deaths in adult white-tailed deer occurred from November 1997 through August 1998 on an Iowa game farm. Three of the 4 deer necropsied had severe pulmonary edema, widespread mild lymphocytic vasculitis, and amphophilic intranuclear inclusion bodies in scattered endothelial cells in blood vessels in the lung and abdominal viscera. Immunohistochemistry with bovine adenovirus 5 antisera and transmission electron microscopy demonstrated adenoviral antigen and nucleocapsids, respectively, within endothelial cells. Adenovirus was isolated in cell culture from 1 of the affected deer. The isolate was neutralized by California black-tailed deer adenovirus antiserum. These findings indicate that adenovirus should be considered in the differential diagnosis of both black-tailed and white-tailed deer with pulmonary edema and/or hemorrhagic enteropathy.

Serologic detection of adenoviral hemorrhagic disease in black-tailed deer in California.

An enzyme-linked immunosorbent assay (ELISA) and a serum neutralization (SN) test were developed to measure serum antibodies against the adenovirus causing hemorrhagic disease in free-ranging and captive experimentally-infected black-tailed deer (Odocoilenus hemionus columbianus) in California (USA). There was a strong (rho = 0.874) and significant (P < 0.0001) correlation between ELISA and SN titers, although the SN assay was more sensitive than the ELISA.

An epizootic of adenovirus-induced hemorrhagic disease in captive black-tailed deer (Odocoileus hemionus).

Ten fawns and four adult black-tailed deer (Odocoileus hemionus) in a captive herd died as a result of adenovirus-induced hemorrhagic disease. Acute, systemic infections were characterized by hemorrhagic enteropathy, pulmonary edema, and occasional ulceration of the upper alimentary tract. Localized infections were limited to the upper alimentary tract and included stomatitis, pharyngitis, mandibular osteomyelitis, and rumenitis. In deer with acute, systemic infections, a diagnosis was made by histopathology and immunohistochemistry. The serum neutralization test was useful for confirming a diagnosis in animals with prolonged, localized infections. Deer originating from herds with a history of adenovirus infection should not be transferred to other captive herds or released into free-ranging populations because they may serve as carriers of adenovirus.

The adenovirus that causes hemorrhagic disease of black-tailed deer is closely related to bovine adenovirus-3.

DNA sequence data was obtained from an adenovirus previously shown to be the cause of a distinctive, fatal hemorrhagic disease of black-tailed deer in California. A 256 base fragment of the viral hexon gene was amplified by PCR from purified adenovirus preparations. The amplicon then was cloned and sequenced. Phylogenetic relationships with other mammalian adenoviruses were also determined. Although sequence analysis of this portion of the hexon gene indicates that the black-tailed deer adenovirus is closely related to bovine adenovirus-3, the biologic properties of the two viruses are clearly distinct.

Manipulation of injury and repair of the alveolar epithelium using two pneumotoxicants: 3-methylindole and monocrotaline.

The role of type II epithelial cell proliferation in repair of diffuse alveolar epithelial injury was examined using two pneumotoxicants, 3-methylindole (3-MI) and monocrotaline (MCT). It was hypothesized that if MCT inhibits type II epithelial cell mitosis, then pulmonary fibrosis would result after diffuse 3-MI-induced type I alveolar cell injury in rats preadministered MCT. Four groups of rats were given vehicle control, MCT, 3-MI, or MCT and 3-MI. Lungs from rats killed 4 days post-treatment were examined subjectively and quantitatively by light and electron microscopy. Proliferative stimulus was estimated by bromodeoxyuridine (BrdU) incorporation. Lungs from rats killed 2 weeks post-treatment were evaluated by light microscopy. At 4 days, the number of type II cells in the lungs of 3-MI-treated rats was 3 times greater than in the lungs of the dually (MCT/3-MI) treated rats which was the same as the control rat lungs. There was no significant difference between the MCT/3-MI-treated rats and the 3-MI-treated rats with regard to the percentage of denuded alveolar basement membrane. The number of BrdU-labeled type II epithelial cells was increased above the control in both 3-MI-treated groups, but was greater in the 3-MI-treated rat lungs than in the lungs of the MCT/3-MI-treated rats. The average type II cell volume in dually treated rats was 3 times the volume in the control animals and 50% greater than that in 3-MI-treated rats. Transmission electron microscopy of the lungs of the MCT/3-MI-treated rats demonstrated flattened hypertrophic type II cells over large portions of the basement membrane. The light microscopic appearance and collagen staining of the lungs of the dually treated rats were similar to the negative control rat lungs 2 weeks after dosing with 3-MI. This suggests that despite a proliferative stimulus, MCT inhibits type II cell division after diffuse alveolar type I cell injury, but that type II cell migration and coverage of the basal lamina proceed. Results of this study suggest that coverage of the denuded basal lamina by any method is sufficient to prevent interstitial alveolar fibrosis.

Lesions and transmission of experimental adenovirus hemorrhagic disease in black-tailed deer fawns.

Adenovirus infection was the cause of an epizootic of hemorrhagic disease that is believed to have killed thousands of mule deer (Odocoileus hemionus) in California during the latter half of 1993. A systemic vasculitis with pulmonary edema and hemorrhagic enteropathy or a localized vasculitis associated with necrotizing stomatitis/pharyngitis/glossitis or osteomyelitis of the jaw were common necropsy findings in animals that died during this epizootic. To study transmission of adenovirus infection in deer and susceptibility of black-tailed deer (Odocoileus hemionus columbianus) fawns to adenovirus infection, six 3-6-month-old black-tailed fawns were divided into two treatment groups. One group was inoculated intravenously and the other group was inoculated through the mucous membranes of the eyes, nose and mouth with purified adenovirus. Each treatment group also included two additional fawns (four total) that were not inoculated but were exposed to inoculated animals (contact animals). One fawn served as a negative control. Between 4 and 16 days postinoculation, 8/10 fawns developed systemic or localized infection with lesions identical to lesions seen in animals with natural disease that died during the epizootic. Transmission was by direct contact, and the route of inoculation did not affect the incubation period or the distribution of the virus (systemic or the localized infection). Immunohistochemical analysis using polyclonal antiserum against bovine adenovirus type 5 demonstrated staining in endothelial cells of vessels in numerous tissues in animals with systemic infection and endothelial staining only in vessels subtending necrotic foci in the upper alimentary tract in animals with the localized form of the disease. All inoculated or exposed animals had staining in the tonsillar epithelium. Transmission electron microscopic examination of lung and ileum from two fawns with pulmonary edema and hemorrhagic enteropathy demonstrated endothelial necrosis and adenovirus virions in endothelial cell nuclei. Adenovirus was reisolated in black-tailed deer pulmonary artery endothelial cells using lung homogenate of the first fawn that developed systemic adenovirus infection. Serum virus neutralization test results suggest that this deer adenovirus is a new serotype.