Comparison of sedation and mechanical antinociception induced by intravenous administration of acepromazine and four dose rates of dexmedetomidine in donkeys.

OBJECTIVE: To assess and compare the sedative and antinociceptive effects of four dosages of dexmedetomidine in donkeys. STUDY DESIGN: Randomized, controlled, crossover, Latin-square, blinded study. ANIMALS: Six healthy, castrated, adult, standard donkeys. METHODS: Dexmedetomidine (2, 3, 4 and 5 µg kg-1; D2, D3, D4 and D5), acepromazine (0.1 mg kg-1) and saline were administered intravenously to each donkey and a 1 week interval was allowed between successive trials on each animal. Sedation scores (SS) and head heights above ground (HHAG) were used to assess sedation and mechanical nociceptive threshold (MNT) testing to assess antinociception over 120 minutes post-treatment. Areas under the curve (AUC) for 0-30, 30-60 and 60-120 minutes were computed to compare the effect of treatments. RESULTS: SS-AUC0-30 values were larger for D4 and D5, and SS-AUC30-60 values were larger for D5 than for saline. All dexmedetomidine treatments produced lower HHAG-AUC0-30 and HHAG-AUC30-60 values, and acepromazine produced lower HHAG AUC60-120 values than did saline. For MNT, D3, D4 and D5 increased AUC0-30 and AUC30-60 values compared with saline and also AUC0-30 values compared with D2 and acepromazine. Smaller MNT-AUC30-60 values were obtained with D2 than with D4 and D5, with D3 than with D5, and with acepromazine than with D4 and D5. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine induced sedation and dosage-dependent mechanical antinociception. Larger dexmedetomidine dose rates were required to induce antinociception than sedation. Furthermore, the antinociception induced by dexmedetomidine was of shorter duration than its sedation. For minor painful procedures on standing donkeys, D5 may be clinically useful to provide sedation and analgesia.

Lower-Than-Expected Vitamin A Concentrations in a Commercial Diet Associated with Uroliths and Pyelonephritis in Rats.

Five of 95 rats in an oral safety study developed uroliths, with two of these rats also developing pyelonephritis. Histology of the urinary tract revealed squamous metaplasia suggestive of vitamin A deficiency. Analysis of the diet showed around half the expected concentration of vitamin A, although the concentrations were close to the published nutritional requirements for rats. Due to the presence of squamous metaplasia of the transitional epithelium and the low vitamin A concentration in the diet, a presumptive diagnosis of vitamin A deficiency was made, although an interaction between the low vitamin A concentrations and other dietary components appears possible. Although the uroliths did not cause clinical signs of disease, the lesions observed during this study could have been misinterpreted as being due to the test substance. Observations from this study highlight the need for high-quality food to ensure background lesions do not develop when performing safety studies in rats.

The Pathology of Fatal Avian Malaria Due to Plasmodium elongatum (GRW6) and Plasmodium matutinum (LINN1) Infection in New Zealand Kiwi (Apteryx spp.).

Avian malaria caused by Plasmodium species is a known cause of mortality in avifauna worldwide, however reports within New Zealand kiwi (Apteryx spp.) are scant. Postmortem reports from kiwi were obtained from the Massey University/Te Kunenga ki Purehuroa School of Veterinary Science Pathology Register from August 2010-August 2020. Gross lesions were described from postmortem reports, and archived H.E.-stained slides used for histological assessment. Nested PCR testing was performed on formalin-fixed paraffin-embedded tissue samples to assess the presence of Plasmodium spp. and Toxoplasma gondii DNA and cases with a PCR-positive result were sequenced to determine the lineage involved. Of 1005 postmortem reports, 23 cases of confirmed or suspected avian malaria were included in this study. The most consistent gross lesions included splenomegaly, hepatomegaly, and interstitial pneumonia with oedema. Histological lesions were characterised by severe interstitial pneumonia, pulmonary oedema, interstitial myocarditis, hepatic sinusoidal congestion and hypercellularity, and splenic macrophage hyperplasia and hyperaemia/congestion with numerous haemosiderophages. Cytoplasmic meronts were consistently found within endothelial cells of a variety of tissues, and within tissue macrophages of the liver, lung and spleen. A diagnosis of avian malaria was confirmed via PCR testing in 13 cases, with sequencing revealing P. matutinum (LINN1) and P. elongatum (GRW6) as the species involved. This is the largest case series describing the pathology of avian malaria as a cause of mortality in endemic New Zealand avifauna.

Animal Welfare Compromises Associated with Causes of Death in Neonatal Piglets.

This pilot study aimed to assess the welfare impacts of different causes of pre-weaning deaths in piglets. Piglets that died between 0-7 days after birth (n = 106) were collected from two commercial pig farms and subject to post-mortem examination to confirm their cause of death as well as any contributing factors. Using the Five Domains Model, the most likely affective experiences associated with the pathological findings were carefully inferred to better understand affective experience as it related to known causes of liveborn piglet mortality. The most common causes of liveborn piglet mortality were starvation (23%), crushing (23%) and non-viable (21%). Thirty one piglets had evidence of starvation, but it was only considered the primary cause of death in 15 piglets, as cofactors such as poor viability (n = 13) were also present in many piglets with evidence of starvation. All 15 piglets that were crushed died within 24 h after birth and most had evidence of thoracic and/or abdominal internal bleeding. This study found that common causes of liveborn piglet death were associated with compromises in Domains 1 (Nutrition/hydration), 3 (Health/function), and4 (Behavioural interactions), with the most likely resulting affective states described in Domain 5 (Mental state). This highlights the interaction between physical/functional and situation-related (behavioural) aspects that influence an animals' welfare status.

Evaluation of a Probability-Based Predictive Tool on Pathologist Agreement Using Urinary Bladder as a Pilot Tissue.

Inter-pathologist variation is widely recognized across human and veterinary pathology and is often compounded by missing animal or clinical information on pathology submission forms. Variation in pathologist threshold levels of resident inflammatory cells in the tissue of interest can further decrease inter-pathologist agreement. This study applied a predictive modeling tool to bladder histology slides that were assessed by four pathologists: first without animal and clinical information, then with this information, and finally using the predictive tool. All three assessments were performed twice, using digital whole-slide images (WSI) and then glass slides. Results showed marked variation in pathologists' interpretation of bladder slides, with kappa agreement values of 7-37% without any animal or clinical information, 23-37% with animal signalment and history, and 31-42% when our predictive tool was applied, for digital WSI and glass slides. The concurrence of test pathologists to the reference diagnosis was 60% overall. This study provides a starting point for the use of predictive modeling in standardizing pathologist agreement in veterinary pathology. It also highlights the importance of high-quality whole-slide imaging to limit the effect of digitization on inter-pathologist agreement and the benefit of continued standardization of tissue assessment in veterinary pathology.

Reference intervals for hematological and biochemical analytes in a single herd of clinically healthy gelding donkeys in Saint Kitts.

There is a large population of donkeys in Saint Kitts; however, hematological and biochemical reference intervals (RIs) are lacking. This study addressed this deficiency by following the American Society for Veterinary Clinical Pathology RI guidelines. Sixty-six healthy, gelding standard donkeys with a median and interquartile range age of 5 years (3.5 - 8 years) and a mean ± standard deviation body weighed of 156 ± 16.7 kg were used to produce a five-part differential complete blood count using an impedance-based analyzer. Clinical chemistry analytes were quantified using a photometric-based analyzer utilizing two reagent rotors that determined 14 and 11 analytes, respectively. An electrochemical-based analyzer quantified chloride, sodium and potassium. Reference intervals were computed using Reference Value Advisor. Results of analytes determined using different rotors/analyzers were assessed using Passing-Bablok regression and Bland-Altman plot analyses. Reference intervals for 43 hematological and biochemical analytes were generated. Reference intervals for hematocrit, red blood cells, white blood cells, total protein, glucose, blood urea nitrogen, and creatinine were 23.67% - 38.08%, 4.08 - 6.42 1012/L, 4.7 - 12.34 109/L, 5.84 - 6.93 g/dL, 64.7 - 130.9 mg/dL, 11.1 - 13.4 mg/dL, and 0.67 - 1.36 mg/dL, respectively. There was good agreement between detection system for albumin, aspartate aminotransferase, gamma glutamyl transferase, total protein, globulin, and potassium, but not for blood urea nitrogen, calcium, creatinine kinase, and sodium. This study is the first to establish hematological and biochemical RIs in donkeys in Saint Kitts. These values will be useful for clinical decision-making.

Detection of Foot-and-Mouth Disease Virus in the Absence of Clinical Disease in Cattle and Buffalo in South East Asia.

Foot-and-mouth disease virus (FMDV) is widespread throughout much of the world, including parts of South East Asia. Surveillance is often limited in endemic areas, relying predominantly on passive outbreak reporting. As part of the World Organisation for Animal Health (OIE)'s South East Asia and China Foot-and-Mouth Disease Project (SEACFMD), field sampling was performed to help understand evidence of widespread virus exposure observed in previous studies. Serum and dry mucosal swabs were collected to evaluate the presence of FMDV RNA on the nasal, oral, and dorsal nasopharyngeal mucosal surfaces of 262 healthy cattle (n = 84 in Laos; n = 125 in Myanmar) and buffalo (n = 48 in Laos; n = 5 in Myanmar) immediately following slaughter in three slaughterhouses. Swabs and serum were tested by the OIE/FAO World Reference Laboratory for foot-and-mouth disease (WRLFMD) using pan-serotypic real-time reverse transcription-PCR (rRT-PCR) and serum was evaluated using the FMD PrioCHECK non-structural protein (NSP) ELISA. In total, 7.3% of animals had detectable FMDV RNA in one or more of the three sites including 5.3% of nasopharyngeal swabs, 2.3% of oral swabs, and 1.5% of nasal swabs. No FMDV RNA was detected in serum. Overall, 37.8% of animals were positive for NSP antibodies, indicating likely past natural exposure to FMDV. Results were comparable for Laos and Myanmar, and for both cattle and buffalo, and were not significantly different between age groups. Detectable FMDV RNA present on the oral and nasal mucosa of clinically-healthy large ruminants in Laos and Myanmar demonstrates the importance of sampling asymptomatic animals as part of surveillance, and may indicate that subclinical infection plays a role in the epidemiology of FMD in these countries.

Hind-limb paresis in a dog with paralumbar solitary T-cell lymphoma.

A 2-year-old, neutered, male golden retriever was referred to the Ontario Veterinary College, with a 6-week history of hind limb weakness and back pain. Magnetic resonance imaging of the lumbar vertebral column, and histopathology and immunohistochemistry following euthanasia identified an uncommon solitary T-cell lymphoma in the paralumbar area.

Clinical and pathologic features of an adenomatous polyp of the colon in a domestic ferret (Mustela putorius furo).

A 6-year-old castrated male domestic ferret (Mustela putorius furo) with a 4-week history of intermittent diarrhea and straining during defecation had an intraluminal mass in the descending colon identified by abdominal ultrasound. The histopathological diagnosis of the resected mass was an adenomatous polyp of the colon. No post-operative complications were identified over a 32-month follow-up period.

Branchial cysts in two Amazon parrots (Amazona species).

A 37-year-old yellow-crowned Amazon parrot (Amazona ochrocephala) and a 20-year-old red-lored Amazon parrot (Amazona autumnalis) each presented with a large mass localized on the lateral neck. With the first bird, there was no evidence of signs of pain or discomfort, and the bird prehended and swallowed food normally. The second bird showed signs of mild upper-gastrointestinal discomfort. Results of an ultrasound examination and aspiration of the mass on each bird revealed a cystic structure. A computed tomography performed on the second bird revealed a large polycystic mass connected to the pharynx by a lateral tract. During surgical resection, both masses were found to originate from the subpharyngeal area. Based on topography and the histopathologic and immunohistochemical results, the masses were determined to be a second branchial cleft cyst for the first case and a second branchial pouch cyst for the second case. In addition, a carcinoma was present in situ within the epithelium of case 1, and the cyst in case 2 was secondarily infected. Branchial cysts are uncommonly diagnosed in veterinary and human medicine. These 2 cases are the first documented in parrots and appear similar to second branchial cysts reported in adult humans.

Ventral dermatitis in rowi (Apteryx rowi) caused by cutaneous capillariasis.

In 2013 there was an outbreak of crusting ventral dermatitis among a group of juvenile rowi (Apteryx rowi), a species of the endangered New Zealand kiwi, that were being raised on an off-shore island sanctuary. Biopsies taken at the time found nematodes migrating within the epidermis of affected skin but the specific identity and origin of the organisms was not established, and sporadic cases of similar skin disease continue to occur on the island. On examination of additional sections from the original skin biopsies, adult nematodes and eggs were identified, the histomorphology of which was consistent with Capillaria sensu lato. PCR was performed on DNA extracted from archived formalin-fixed, paraffin-embedded tissue blocks of skin from eight affected rowi, using primers targeting the 18S region of nuclear ribosomal DNA and the COI gene of mitochondrial DNA of capillarid nematodes. The 18S sequences from all rowi samples were identical and matched sequences from members of the genus Eucoleus. In contrast, two distinct capillarid COI sequences were obtained, in one case both from the same rowi skin biopsy. While there were no close matches, both COI sequences also aligned nearest to sequences identified as Eucoleus spp. It is considered unlikely that two different nematode species are involved in the rowi skin lesions and the possible amplification of a COI pseudogene or "numt" is discussed. A species-level identification of the capillarid nematodes causing skin disease in rowi was not obtained, however based on histological evaluation the infections include reproductively-active adult nematodes. This finding indicates the possibility of perpetuation of the skin disease in the absence of the original source, as well as raising potential for the transfer of infection from the island when the juvenile rowi are translocated to their new habitats.

Nematode larva migrans caused by Toxocara cati in the North Island brown kiwi (Apteryx mantelli).

Sporadic cases of visceral and neural nematode larva migrans have been diagnosed at necropsy in the endangered New Zealand kiwi (Apteryx spp.), but the causative organisms have not yet been definitively identified. From an initial group of five affected kiwi, PCR was performed on DNA extracted from archival formalin-fixed paraffin-embedded tissue sections in which larval nematodes had been histologically identified. Sequencing of positive results from four out of the five kiwi aligned with sequences from Toxocara cati, a nematode parasite whose definitive host is the domestic cat. PCR was then performed on a second group of 12 kiwi that had histologic inflammatory lesions consistent with larva migrans, but variable larval presence. Repeatable positive PCR results were only achieved in one tissue, in which larval organisms were histologically confirmed. This study supports the use of PCR as an alternative or adjunct to the morphological identification of nematode larvae in formalin-fixed histopathological samples, as well as showing that in investigation of larva migrans, PCR has greatest chance of success from sections where nematode larvae are evident histologically. The identification of Toxocara cati from lesions of larva migrans in kiwi reflects an indirect, parasite-mediated effect of an invasive mammalian species on a native species.

Sedative and mechanical antinociceptive effects of four dosages of romifidine administered intravenously to donkeys.

Although romifidine is commonly used to provide sedation and analgesia for the facilitation of clinical procedures in donkeys, limited scientific information is available for this drug in this species. This randomized, controlled, crossover, Latin-square, blinded study compared the sedative and antinociceptive effects of four dosages of romifidine (40, 60, 80, and 100µg/kg IV; R40, R60, R80, and R100, respectively), acepromazine (0.1mg/kg IV; ACE) and saline (0.9%, 5mL IV) by assigning sedation scores (SS) and measuring head heights above ground (HHAG) and mechanical nociceptive thresholds (MNT) in donkeys. Areas under the curve (AUC) from 0 to 30, 30-60, 60-120, and 120-180min after administration were computed for SS, HHAG, and MNT and compared among treatments. Romifidine and ACE, but not saline, induced clinical signs of sedation. SS-AUC0-30 for R60, R80 and R100, and SS-AUC30-60 for R100 were higher than corresponding values for saline. HHAG-AUC30-60 for R40 and R80, and HHAG-AUC60-120 for R40, R60, R80 and R100 were smaller than for saline. HHAG-AUC60-120 for R100 were also smaller than those for ACE. Romifidine, but not saline or ACE, increased MNT. MNT-AUC0-30 and MNT-AUC30-60 for R40, R60, R80 and R100, and MNT-AUC60-120 for R80 and R100 were higher than corresponding values for saline and ACE. MNT-AUC60-120 for R100 were higher than for all other romifidine treatments. In donkeys, the degree of sedation was similar for the four dosages of romifidine, but antinociception was dose-dependent.

Sedation and mechanical hypoalgesia after sublingual administration of detomidine hydrochloride gel to donkeys.

OBJECTIVE To compare sedative and mechanical hypoalgesic effects of sublingual administration of 2 doses of detomidine gel to donkeys. DESIGN Randomized blinded controlled trial. ANIMALS 6 healthy castrated male donkeys. PROCEDURES In a crossover study design, donkeys received each of the following sublingual treatments 1 week apart in a randomly assigned order: 1 mL of molasses (D0) or detomidine hydrochloride gel at 20 µg/kg (9 µg/lb; D20) or 40 µg/kg (18 µg/lb; D40). Sedation score (SS), head height above the ground (HHAG), and mechanical nociceptive threshold (MNT) were assessed before and for 180 minutes after treatment. Areas under the effect change-versus-time curves (AUCs) from 0 to 30, 30 to 60, 60 to 120, and 120 to 180 minutes after administration were computed for SS, HHAG, and MNT and compared among treatments. RESULTS D20 and D40 resulted in greater SS AUCs from 60 to 120 minutes and smaller HHAG AUCs from 30 through 180 minutes than did D0. The D40 resulted in smaller HHAG AUCs from 60 to 120 minutes than did D20. Compared with D0 values, MNT AUCs from 60 to 120 minutes were higher for D20, whereas MNT AUCs from 30 through 180 minutes were higher for D40. CONCLUSIONS AND CLINICAL RELEVANCE D20 and D40 induced sedation and mechanical hypoalgesia in donkeys by > 30 minutes after administration, but only sedation was dose dependent. Sublingual administration of detomidine gel at 40 µg/kg may be useful for sedation of standing donkeys prior to potentially painful minor procedures.

First case of canine leishmaniasis on the island of St. Kitts, West Indies.

Leishmaniasis caused by Leishmania infantum is an emerging/re-emerging zoonosis with dogs as the main reservoir. The first autochthonous case of canine leishmaniasis in St. Kitts was diagnosed, and had cutaneous involvement. This discovery expands the distribution of leishmaniasis to include this insular country in the West Indies and dictates further characterization of the disease in this region.

Sedation and mechanical antinociception after intravenous administration of detomidine in donkeys: a dosage-effect study.

There is limited, useful, scientific information on detomidine in donkeys. This study compared the effects of intravenous saline, detomidine (10, 13.5, 17 and 20 µg/kg) and acepromazine (50 µg/kg) in donkeys by computing areas under the curve for 0-30, 30-60 and 60-120 minutes (AUC0-30, AUC30-60 and AUC60-120) for sedation scores, head heights and mechanical nociceptive thresholds (MNTs). For sedation scores, all detomidine treatments, except 10 µg/kg, increased AUC0-30 values compared with saline, and AUC0-30 values were larger for 17 µg/kg detomidine than for acepromazine. All head height AUC values were lower for detomidine than for saline (except AUC60-120 for 10 µg/kg detomidine) and acepromazine (except AUC0-30 for 10 and 20 µg/kg detomidine, and AUC60-120 for 10 µg/kg detomidine). For MNTs, all detomidine treatments increased AUC0-30 and AUC30-60 values compared with saline and acepromazine; AUC30-60 values were smaller for 10 µg/kg than for 17 and 20 µg/kg detomidine. MNT AUC60-120 values were larger for 20 µg/kg detomidine than for saline, 10 µg/kg detomidine and acepromazine. Detomidine induced sedation and antinociception, but only antinociception was dosage dependent. Selection of detomidine dosage for donkeys may depend on the required duration of sedation and/or degree of analgesia.

An outbreak of Yersinia enterocolitica in a captive colony of African green monkeys (Chlorocebus aethiops sabaeus) in the Caribbean.

Yersinia enterocolitica is a zoonotic gram-negative pathogen that causes mesenteric lymphadenitis, terminal ileitis, acute gastroenteritis, and septicemia in domestic animals and primates. In 2012, 46 captive African green monkeys (Chlorocebus aethiops sabaeus) died during an outbreak of acutely fatal enteric disease over a period of 1 mo on the island of St Kitts. The affected monkeys presented with a history of mucohemorrhagic diarrhea, marked dehydration, and depression. Fifteen bacterial isolates were recovered from the spleen, liver, and lungs of affected monkeys. All isolates were identified as Y. enterocolitica by biochemical analysis and sequence comparison of the 16S rRNA gene. Phenotypic and genotypic analysis of the recovered isolates revealed homogeneity among the recovered bacteria, and all isolates gave a random amplified polymorphic DNA pattern resembling that given by genotype D under serotypes O:7,8. This outbreak represents the first isolation and characterization of Y. enterocolitica as the causative agent of fatal enteric disease in primates in the Caribbean.

Prevalence and genotype of Mycoplasma bovis in beef cattle after arrival at a feedlot.

OBJECTIVE: To determine the prevalence of Mycoplasma bovis infection in the lungs of cattle at various times after arrival at a feedlot, to measure the relationship between clinical disease status and the concentration and genotype of M bovis within the lungs, and to investigate changes in the genotype of M bovis over time. SAMPLE: Bronchoalveolar lavage fluid (BALF) from 328 healthy or pneumonic beef cattle and 20 M bovis isolates obtained from postmortem samples. PROCEDURES: The concentration of M bovis in BALF was determined via real-time PCR assays, and M bovis isolates from BALF were genotyped via amplified fragment length polymorphism (AFLP) analysis. RESULTS: Prevalence of M bovis in BALF was 1 of 60 (1.7%) at arrival to a feedlot and 26 of 36 (72.2%) and 36 of 42 (85.7%) at ≤ 15 days and 55 days after arrival, respectively. Neither the concentration nor the AFLP type of M bovis in BALF was correlated with clinical disease status. The M bovis AFLP type differed between early and later sampling periods in 14 of 17 cattle. CONCLUSIONS AND CLINICAL RELEVANCE: The findings implied spread of M bovis among calves and suggested that host factors and copathogens may determine disease outcomes in infected calves. Chronic pulmonary infection with M bovis may represent a dynamic situation of bacterial clearance and reinfection with strains of different AFLP type, rather than continuous infection with a single clone. These findings impact our understanding of why cattle with chronic pneumonia and polyarthritis syndrome inadequately respond to antimicrobial treatment.

Molecular and immunohistochemical diagnosis of Francisella noatunensis subsp. orientalis from formalin-fixed, paraffin-embedded tissues.

Members of the genus Francisella (viz., F. noatunensis subsp. orientalis [Fno] and F. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. In the present study, 68 archived formalin-fixed, paraffin-embedded (FFPE) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detection of the Fno intracellular growth loci C (iglC) gene and by immunohistochemistry for the demonstration of Fno antigens. The results revealed a high correlation between these 2 diagnostic techniques validating their use for the diagnosis of Fno infection in archived FFPE tissues and confirming the presence of Fno in fish species from the Cari y years of the present century.

Mycoplasma bovis in respiratory disease of feedlot cattle.

Mycoplasma bovis has recently emerged as an important cause of chronic caseonecrotic bronchopneumonia, arthritis, and tenosynovitis in beef cattle. Mycoplasma bovis can act as a primary pathogen, yet many cases are coinfected with other bacteria or viruses, and evidence suggests that M. bovis colonizes and perpetuates lung lesions that were initiated by other bacteria, such as M. haemolytica. Mycoplasma bovis elicits a robust humoral immune response, but the resulting antibodies are not protective because of the variable surface proteins, and vaccines have not yet been shown to prevent disease. Mycoplasma bovis infections are responsible for a high proportion of the chronic disease occurring in feedlots, and the welfare of such animals is an important aspect of feedlot health management.