Genetically edited pigs lacking CD163 show no resistance following infection with the African swine fever virus isolate, Georgia 2007/1.

African swine fever is a highly contagious, often fatal disease of swine for which there is no vaccine or other curative treatment. The macrophage marker, CD163, is a putative receptor for African swine fever virus (ASFV). Pigs possessing a complete knockout of CD163 on macrophages were inoculated with Georgia 2007/1, a genotype 2 isolate. Knockout and wild type pen mates became infected and showed no differences in clinical signs, mortality, pathology or viremia. There was also no difference following in vitro infection of macrophages. The results do not rule out the possibility that other ASFV strains utilize CD163, but demonstrate that CD163 is not necessary for infection with the Georgia 2007/1 isolate. This work rules out a significant role for CD163 in ASFV infection and creates opportunities to focus on alternative receptors and entry mechanisms.

Tissue localization, shedding, virus carriage, antibody response, and aerosol transmission of Porcine epidemic diarrhea virus following inoculation of 4-week-old feeder pigs.

We determined tissue localization, shedding patterns, virus carriage, antibody response, and aerosol transmission of Porcine epidemic diarrhea virus (PEDV) following inoculation of 4-week-old feeder pigs. Thirty-three pigs were randomly assigned to 1 of 3 groups for the 42-day study: inoculated (group A; n = 23), contact transmission (group B; n = 5), and aerosol transmission (group C; n = 5). Contact transmission occurred rapidly to group B pigs whereas productive aerosol transmission failed to occur to group C pigs. Emesis was the first clinical sign noted at 3 days postinoculation (dpi) followed by mild to moderate diarrhea lasting 5 more days. Real-time PCR detected PEDV in fecal and nasal swabs, oral fluids, serum, and gastrointestinal and lymphoid tissues. Shedding occurred primarily during the first 2 weeks postinoculation, peaking at 5-6 dpi; however, some pigs had PEDV nucleic acid detected in swabs collected at 21 and 28 dpi. Antibody titers were measurable between 14 and 42 dpi. Although feces and intestines collected at 42 dpi were PEDV negative by PCR and immunohistochemistry, respectively, small intestines from 70% of group A pigs were PCR positive. Although disease was relatively mild and transient in this age group, the results demonstrate that 4-week-old pigs are productively infected and can sustain virus replication for several weeks. Long-term shedding of PEDV in subclinically affected pigs should be considered an important source for PEDV transmission.

SUSPECTED FENBENDAZOLE TOXICITY IN AN AMERICAN WHITE PELICAN (PELECANUS ERYTHRORHYNCHOS).

A wild-raised, 5.0-kg male American white pelican ( Pelecanus erythrorhynchos ) of unknown age presented for routine examination at both the start and completion of a 30-day quarantine period at a zoological park. Upon physical examination, the pelican was bright, alert, and responsive and in good body condition. Two complete blood counts and a plasma biochemistry did not reveal any clinically significant abnormalities. Whole-body radiographs were unremarkable. Two fecal flotations (28 days apart) confirmed the presence of ascarid-type eggs. Fenbendazole anthelmintic was prescribed (50 mg/kg p.o. s.i.d. for 5 days). The pelican became lethargic and inappetent on day 3 of fenbendazole treatment and was found dead on day 7. Postmortem examination and histopathology revealed intestinal crypt cell necrosis, stomatitis, and splenic lymphoid depletion consistent with fenbendazole toxicity. To the authors' knowledge, this is the first report to describe fenbendazole toxicity in an American white pelican.

MULTICENTRIC T-CELL LYMPHOMA AND CUTANEOUS HEMANGIOSARCOMA IN A CAPTIVE CHEETAH (ACINONYX JUBATUS).

A 13-yr-old intact male cheetah (Acinonyx jubatus) presented for evaluation after a 4-mo history of intermittent lethargy and increased expiratory effort. The clinical signs were initially noted after the diagnosis and death of its 13-yr-old male sibling with solitary hepatic T-cell lymphoma. Physical examination findings included thin body condition, harsh lung sounds, peripheral lymphadenopathy, and a cutaneous mass on the right medial tarsus and scrotum. Excisional biopsies diagnosed well-differentiated cutaneous hemangiosarcomas. Thoracic radiographs revealed a cranial mediastinal mass. Complete blood count and serum biochemical analyses showed a leukocytosis with persistent lymphocytosis, progressive azotemia, and markedly elevated alkaline phosphatase. Because of the cheetah's declining quality of life, euthanasia was elected. Postmortem examination, histopathology, and immunohistochemical staining revealed multicentric T-cell lymphoma. Feline leukemia virus (FeLV) enzyme-linked immunosorbent assay, FeLV polymerase chain reaction (whole blood), and viral metagenomic analysis were negative. This is the first case of cutaneous hemangiosarcoma and multicentric T-cell lymphoma reported in a FeLV-negative cheetah.

Pharmacokinetics of meloxicam administered orally to rabbits (Oryctolagus cuniculus) for 29 days.

OBJECTIVE: To determine the pharmacokinetics and safety of meloxicam in rabbits when administered orally for 29 days. ANIMALS: 6 healthy rabbits. PROCEDURES: Meloxicam (1.0 mg/kg, PO, q 24 h) was administered to rabbits for 29 days. Blood was collected immediately before (time 0) and 2, 4, 6, 8, and 24 hours after drug administration on days 1, 8, 15, 22, and 29 to evaluate the pharmacokinetics of meloxicam. On day 30, an additional sample was collected 36 hours after treatment. Plasma meloxicam concentrations were quantified with liquid chromatography-mass spectrometry, and noncompartmental pharmacokinetic analysis was performed. Weekly plasma biochemical analyses were performed to evaluate any adverse physiologic effects. Rabbits were euthanatized for necropsy on day 31. RESULTS: Mean ± SD peak plasma concentrations of meloxicam after administration of doses 1, 8, 15, 22, and 29 were 0.67 ± 0.19 µg/mL, 0.81 ± 0.21 µg/mL, 1.00 ± 0.31 µg/mL, 1.00 ± 0.29 µg/mL, and 1.07 ± 0.19 µg/mL, respectively; these concentrations did not differ significantly among doses 8 through 29. Results of plasma biochemical analyses were within reference ranges at all time points evaluated. Gross necropsy and histologic examination of tissues revealed no clinically relevant findings. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma concentrations of meloxicam for rabbits in the present study were similar to those previously reported in rabbits that received 1. 0 mg of meloxicam/kg, PO every 24 hours, for 5 days. Results suggested that a dosage of 1. 0 mg/kg, PO, every 24 hours for up to 29 days may be safe for use in healthy rabbits.

Intermittent single-agent doxorubicin for the treatment of canine B-cell lymphoma.

Canine B-cell lymphoma is a highly treatable disease, but cost and logistical factors may hamper an owner's ability to pursue treatment of their pet with this disease. The authors evaluated the use of single-agent doxorubicin in an intermittent fashion for efficacy in the treatment of this disease. Morphologic and clinical data were analyzed for prognostic significance. Eighteen dogs with B-cell lymphoma, all with multicentric disease, were enrolled. The overall complete response (CR) rate was 78%, median total doxorubicin remission time (TDR) was 80.5 days, and median overall survival (OS) was 169.5 days. The median number of doxorubicin doses administered was 4.5. First remission times were significantly affected by clinical stage and substage of disease. Outcome for the dogs in this study were similar to those previously reported for single-agent doxorubicin treatment. Additionally, the intermittent nature of the treatments made the described protocol more feasible for the owners who enrolled their pets in this study. Intermittent single-agent doxorubicin is not a substitute for multiagent chemotherapy protocols in the treatment of canine lymphoma; however, it is a reasonable alternative if the cost and time commitments are limiting factors for an owner.

Neuropathology and diagnostics in food animals.

Diseases of the central nervous system (CNS) are relatively common in food animals. Potential causes include infectious agents, nutritional deficiencies, metabolic disorders, genetic defects, toxins, and idiopathic causes. Determining the correct etiologic diagnosis often depends on a thorough postmortem examination and collection of samples. This article reviews some of the steps and procedures necessary to collect the necessary information on CNS diseases in food animals. Techniques for the examination of the CNS are briefly described, and some of the gross pathology likely to be encountered in a food animal practice is reviewed.

Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle or needle-free injection.

Nursery-age pigs (n=198) were used to evaluate the difference in abscess formation at needle-free jet and conventional needle-and-syringe injection sites. Needle-free jet injection was used to administer injections in the neck and ham on one side of the animal whereas needle-and-syringe was used for neck and ham injections on the opposite side. Immediately prior to injection, the injection site surfaces were contaminated with an inoculum of Arcanobacterium pyogenes. Each pig was humanely euthanized 27 or 28 days after injections. Histopathological results showed that needle-free jet injection was associated with more abscesses than needle-and-syringe injection at both neck (P=0.0625) and ham (P=0.0313) injection sites. Out of 792 injection sites, only 13 abscesses were observed, with 12 of those present at needle-free jet injection sites. Needle-free jet injection may increase the occurrence of injection site abscesses that necessitate carcass trimming at pork processing plants.

Investigation of a Microcystis aeruginosa cyanobacterial freshwater harmful algal bloom associated with acute microcystin toxicosis in a dog.

Microcystin poisoning was diagnosed in a dog exposed to a Microcystis aeruginosa-dominated, freshwater, harmful algal bloom at Milford Lake, Kansas, which occurred during the summer of 2011. Lake water microcystin concentrations were determined at intervals during the summer, using competitive enzyme-linked immunosorbent assays, and indicated extremely high, localized microcystin concentrations of up to 126,000 ng/ml. Multiple extraction and analysis techniques were used in the determination of free and total microcystins in vomitus and liver samples from the poisoned dog. Vomitus and liver contained microcystins, as determined by enzyme-linked immunosorbent assays, and the presence of microcystin-LR was confirmed in vomitus and liver samples using liquid chromatography coupled with tandem mass spectrometry. Major toxic effects in a dog presented for treatment on the day following exposure included fulminant liver failure and coagulopathy. The patient deteriorated rapidly despite aggressive treatment and was euthanized. Postmortem lesions included diffuse, acute, massive hepatic necrosis and hemorrhage, as well as acute necrosis of the renal tubular epithelium. A diagnosis of microcystin poisoning was based on the demonstration of M. aeruginosa and microcystin-LR in the lake water, as well as in vomitus produced early in the course of the poisoning; the presence of microcystin-LR in liver tissue; and a typical clinical course including gastroenteritis and fulminant liver failure.

Canine schistosomiasis in Kansas: five cases (2000-2009).

This is a retrospective case series consisting of five dogs diagnosed with schistosomiasis. The purpose of this article is to report the presence of naturally occurring canine schistosomiasis in Kansas and to provide clinical details regarding schistosomiasis. Medical records of dogs diagnosed with schistosomiasis from 2000 to 2009 were reviewed, and information extracted included signalment, history, clinical signs, diagnostic test results, treatment, and outcome. Affected dogs were primarily medium to large breed and young to middle aged. All dogs were considered outdoor dogs, with three having known access to surface water. Common clinical signs included gastrointestinal disease and signs associated with hypercalcemia. Fecal flotation was negative in all dogs in contrast to fecal saline sedimentation and fecal polymerase chain reaction, which were both positive in all dogs in which it was performed. All dogs treated specifically for schistosomiasis fully recovered. This article describes the first reported cases of canine schistosomiasis in the Midwest and the first reported case of intestinal intussusception secondary to schistosomiasis. Recognizing that canine schistosomiasis is present in Kansas and possibly other Midwestern states should prompt veterinarians to perform appropriate diagnostic investigation in suspect animals as the diagnosis is straight forward and relatively inexpensive.

Adverse health effects in Canada geese (Branta canadensis) associated with waste from zinc and lead mines in the Tri-State Mining District (Kansas, Oklahoma, and Missouri, USA).

Lead and zinc poisoning have been recorded in a variety of bird species, including migrating waterfowl such as Canada Geese (Branta canadensis), at sites contaminated with mine waste from lead and zinc mines in the Tri-State Mining District, Kansas, Oklahoma, and Missouri, USA. The adverse health impacts from mine waste on these birds may, however, be more extensive than is apparent from incidental reports of clinical disease. To characterize health impacts from mine waste on Canada Geese that do not have observable signs of poisoning, four to eight apparently healthy birds per site were collected from four contaminated sites and an uncontaminated reference site, and examined for physical and physiologic evidence of metals poisoning. Tissue concentrations of silver, aluminum, arsenic, barium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead, selenium, thallium, vanadium, and zinc were determined by inductively coupled plasma mass spectroscopy. Adverse health effects due to lead were characterized by assessing blood δ-aminolevulinic acid dehydratase (ALAD) enzyme activity. Adverse effects associated with zinc poisoning were determined from histologic examination of pancreas tissues. Elevated tissue lead concentrations and inhibited blood ALAD enzyme activities were consistently found in birds at all contaminated sites. Histopathologic signs of zinc poisoning, including fibrosis and vacuolization, were associated with elevated pancreatic zinc concentrations at one of the study sites. Adverse health effects associated with other analyzed elements, or tissue concentrations indicating potentially toxic exposure levels to these elements, were not observed.

Characterization of a new disease syndrome associated with porcine circovirus type 2 in previously vaccinated herds.

Porcine circovirus-associated disease (PCVAD) encompasses a group of wasting syndromes linked to porcine circovirus type 2 (PCV2). This paper describes a new PCV2 disease syndrome, called acute pulmonary edema (APE), which, unlike other PCVAD syndromes, has a peracute onset and is associated with herds vaccinated for PCV2.

Field necropsy techniques and proper specimen submission for investigation of emerging infectious diseases of food animals.

This article briefly reviews criteria for selecting animals for necropsy and outlines necropsy procedure and samples to collect when investigating new or emerging diseases of food animals. It gives recommendations on how to collect samples for submission to a diagnostic laboratory and how to package and ship the samples so that they comply with federal regulations concerning shipment of diagnostic samples that might contain infectious substances.

A field evaluation of mortality rate and growth performance in pigs vaccinated against porcine circovirus type 2.

OBJECTIVE: To evaluate, under field conditions, the effects of a commercial porcine circovirus type 2 (PCV2) vaccine on mortality rate and growth performance in a herd infected with PCV2 that had a history of porcine circovirus disease. DESIGN: Randomized controlled clinical trial. ANIMALS: 485 commercial, cross-bred, growing pigs. PROCEDURES: Prior to weaning, pigs were randomly assigned within litter to a vaccination or unvaccinated control group. Pigs in the vaccination group were given a commercial PCV2 vaccine at weaning and 3 weeks later. Mortality rate was recorded, and pigs were weighed prior to vaccination, when moved from the nursery, and prior to marketing. Infection status was assessed by serologic testing and detection of viral DNA in serum. RESULTS: Compared with control pigs, pigs vaccinated against PCV2 had a significantly lower mortality rate during the finishing phase, significantly higher average daily gain during the finishing phase, and significantly lower likelihood of being lightweight at the time of marketing. For vaccinated pigs, overall mortality rate was reduced by 50% and average daily gain during the finishing period was increased by 9.3%. At the time of marketing, vaccinated pigs weighed an average of 8.8 kg (19.4 lb) more than control pigs, without any difference in days to marketing. Serum PCV2 antibody titers increased in control pigs, and PCV2 DNA was detected, indicating active PCV2 infection. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that vaccination against PCV2 was effective at reducing mortality rate and improving growth performance among pigs in a herd infected with PCV2.

Dysautonomia in dogs: 65 cases (1993-2000).

OBJECTIVE: To determine signalment, history, clinical findings, results of autonomic function testing and other antemortem diagnostic tests, and pathologic findings in dogs with dysautonomia. DESIGN: Retrospective study. ANIMALS: 65 dogs with dysautonomia. PROCEDURE: Case records of 68 dogs with a diagnosis of dysautonomia were reviewed; inclusion criteria included histologic confirmation of dysautonomia or clinical signs and results of pharmacologic testing consistent with dysautonomia. RESULTS: 65 dogs fulfilled all criteria for dysautonomia. Dogs from rural environments were overrepresented, and cases of dysautonomia were reported for every month, although the highest number of cases was reported in February and March. Vomiting was the most common clinical sign, followed by diarrhea, signs of anorexia and depression, weight loss, and dysuria. The most common physical examination finding was decreased or absent anal tone, followed by absent pupillary light reflexes and elevated nictitating membrane. Results of pharmacologic testing were consistent with dysautonomia, although no single test was 100% sensitive. Histologic lesions consistent with dysautonomia were found in the autonomic ganglia, brainstem nuclei, and ventral horns of the spinal cord. CONCLUSIONS AND CLINICAL RELEVANCE: Dysautonomia is an endemic disease in Kansas, and a high index of suspicion of the disease can be made by combining clinical signs, physical examination findings, and results of pharmacologic testing.

Fatal cytauxzoonosis in a free-ranging bobcat (Lynx rufus).

In September 2000, a free-ranging bobcat (Lynx rufus) cub was presented to the Kansas State University Veterinary Teaching Hospital (Manhattan, Kansas, USA) in a moribund state with signs of severe anemia and respiratory difficulty. The cub was euthanized. Gross necropsy findings included multifocal atelectasis, splenomegaly, and pericardial effusion. Microscopic examination revealed subacute pulmonary thrombosis, mild vasculitis in the brain, and large schizont-filled macrophages within blood vessels of all tissues examined. The organisms were typical of the developmental stages of Cytauxzoon felis. Cytauxzoonosis is considered to be a persistent, subclinical infection in the bobcat; however, this cub had lesions consistent with those seen in fatal infections in domestic cats. This case of fatal C. felis infection indicates that some free-ranging bobcats may die of cytauxzoonosis.

A familial degenerative neuromuscular disease of Gelbvieh cattle.

A degenerative skeletal muscle disease with vascular, neurologic, and renal lesions and a probable familial distribution was identified in 4-20-month-old purebred Gelbvieh cattle. Thirteen affected animals were confirmed from 6 separate beef herds, with a mortality rate of 100%. Clinical signs in affected animals consisted of ataxia, weakness, and terminal recumbency. Gross and histologic muscle lesions were indicative of nutritional myopathy of ruminants, with a lack of myocardial lesions in most cases and only rare myocardial changes in a few animals. Acute to chronic lesions in most large skeletal muscle groups consisted of degeneration, necrosis, regeneration, fibrosis, and atrophy. Fibrinoid necrosis of arterioles was a common feature in multiple tissues. Lesions in the spinal cord white matter and peripheral nerves consisted of degeneration of the dorsal columns and axons, respectively. Changes in the kidneys consisted of chronic interstitial nephritis with fibrosis, hyaline droplet change and tubular epithelial vacuolar change and were most severe in the older calves. Intracytoplasmic myoglobin and iron were demonstrated within the hyaline droplets in degenerate renal cortical tubular epithelial cells. Vitamin E levels were deficient in most (6/7) of the animals tested. Investigation of the pedigree of affected animals revealed a common ancestry for all but 1 of the animals whose parentage could be traced. This investigation suggests that a hereditary metabolic defect, possibly involving antioxidant metabolism, could be responsible for this condition. Renal disease, possibly secondary to myoglobinuria, may be unique to this bovine condition.