Induction of Anesthesia Using Diazepam/Ketamine in Dogs with Complete Heart Block A Preliminary Report

Intravenous diazepam and ketamine were used to induce anesthesia in four dogs with complete heart block while cardiac and hemodynamic measurements were made. Immediately after induction there were minor changes in the measured variables. However, 5 minutes after injection, with the dogs supine and mechanically ventilated, cardiac output was reduced 41%. An additional 20 dogs with heart block had uncomplicated induction when this drug combination was used. The combination of diazepam and ketamine appears useful for inducing anesthesia in dogs with heart lesions, although further studies must be done to establish its value in such patients.     

Oral, nasal, and cutaneous eosinophilic granulomas in the black rhinoceros (Diceros bicornis): a lesion distinct from superficial necrolytic dermatitis.

Oral, nasal, and cutaneous lesions resembling eosinophilic granulomas (EGs) were observed in eight captive black rhinoceroses (Diceros bicornis). Oral lesions were observed in all affected animals and occurred most often behind the prehensile lip. The typical clinical history of affected animals included oral bleeding or epistaxis from multilobulated, fungating, proliferative masses with areas of ulceration. Histologically, lesions were characterized by prominent infiltrates of eosinophils and rare foci of collagen degeneration on a background of marked submucosal or dermal neovascularization. Mucosal or epidermal hyperplasia was also present sometimes in association with distinctive epithelial degenerative changes consistent with superficial necrolytic dermatopathy of black rhinoceroses. Lesions of EG and superficial necrolytic dermatopathy were interpreted as being concurrently manifested in these cases. EG lesions spontaneously resolved over periods of 30 days-7 mo and were recurrent in three animals. Lesions were responsive to treatment with corticosteroids or to local cryotherapy with liquid nitrogen. Two animals treated with systemic corticosteroids died of disseminated fungal infections, emphasizing that corticosteroids should be used cautiously in black rhinoceroses.     

The influence of crumble and mash feed on oral lesions of white leghorn laying hens.

The effect of crumble and mash feed on oral lesions in laying hens was investigated. Each of two groups of white leghorn hens (group A, n = 120; group B, n = 120) was separated into crumble- and mash-fed treatments. At the start of the trial, group A chickens were free of oral lesions, whereas group B chickens had nearly 100% prevalence of oral lesions. The trials began at 17.4 and 22 wk of age and ended at 32 and 33 wk of age for groups A and B, respectively. Chickens were housed in cages indoors, fed free choice, and serologically monitored. Oral lesions were periodically evaluated by visual scoring. Lesion prevalence peaked in group A chickens at 23-25 wk of age, concurrently with an outbreak of respiratory disease, and decreased to a low level at the end of the trial. For most of the trial, crumble-fed chickens had significantly lower oral lesion prevalence than mash-fed chickens (P < 0.05). Lesion prevalence in group B chickens decreased after treatments began and maintained this trend to the end of the trial. Compared with mash-fed chickens, crumble-fed chickens in group B had significantly lower oral lesion prevalence throughout the trial (P < 0.001). Neither group had significant differences in oral lesion scores between treatments. Most lesions were on the lower palate, pinpoint to 2 mm in diameter, often multiple, and bilaterally symmetrical. Feed analyses for mycotoxins and heavy metals were within normal limits. The inciting etiology of oral lesions was not elucidated in this trial. However, this work demonstrated that once lesions were present, feed type had a strong effect on persistence of oral lesions.     

Cutaneous Serratia marcescens infection in two dogs

We describe two canine cases of cutaneous infection caused by Serratia marcescens. A 2-year-old castrated male mixed dog (Case 1) presented with multiple ulcerations on the dorsal trunk, which were observed 4 days after shampooing. A 4-year-old male wolf shepherd mix dog (Case 2) presented with ulceration and purulent discharge on the nasal bridge. Cytological examination of both cases revealed pyogranulomatous inflammatory cells with rod-like infectious agents identified as S. marcescens in aerobic bacterial culture. Both patients were treated with oral antibiotics and topical chlorhexidine. Case 1 received enrofloxacin 10 mg/kg once daily for 1 week, followed by trimethoprim/sulfamethoxazole 15 mg/kg twice daily for 3 weeks. Case 2 received doxycycline 10 mg/kg twice daily for 4 weeks. No skin lesions were detected 2 weeks after the initial administration. The antibiotics were discontinued after a total 4 weeks of administration, and the skin lesions did not reappear.     

Chemical Involution of the Equine Parotid Salivary Gland

The efficacy of eliminating parotid salivary secretions by retrograde infusion of 10% formalin, 2% chlorhexidine, or 2% or 3% silver nitrate solutions was evaluated in 10 horses. Solutions were kept within the parotid salivary gland for 90 seconds after infusion through parotid duct cannulae and then allowed to drain freely. Severed parotid ducts and surgical incisions were left to heal by second intention. All agents eliminated glandular secretions. There was less necrosis and suppurative inflammation after formalin infusion than after chlorhexidine and silver nitrate. Silver nitrate (2% and 3%) caused the most necrosis and inflammation.     

Studies on the pathogenesis of pseudorabies in domestic cats following oral inoculation.

Domestic cats were inoculated orally with an Iowa isolate of pseudorabies virus. Several cats were killed at intervals of one day and tissues were examined virologically and histologically to determine the initial sites of virus penetration and replication and to evaluate the pathways traveled by the virus from the mouth to the central nervous system. Lesions were consistent in the tonsils, along the pathways of the sensory branches of the ninth and tenth cranial nerves, the tractus and nucleus solitarius and the area postrema in the medulla. Less consistent lesions in the ganglia and nuclei of the fifth cranial nerve indicated a lesser role for the passage of virus via this nerve. Nervous lesions consisted of multifocal to diffuse microgliosis, mononuclear perivascular cuffing and a mononuclear inflammatory cell infiltration with a variable number of neutrophils occasionally forming microabscesses. Virus isolations correlated well with microscopic lesions. Ultrastructurally, virions were observed within the nucleus of the neurons in the medulla. Clinical signs were similar to those previously reported. Pruritus was consistently absent. Virus was isolated consistently for the first two or three days postinoculation from oral and nasal secretions but not from secretions after three days.     

Comparisons between two isolates of stomatitis papulosa virus

The cytopathology and length of latency in single-step growth curves of two isolates of stomatitis papulosa virus are compared in this report. Isolate 721 was obtained from a calf with oral ulcers and isolate 8665 was obtained from a calf with respiratory disease and oral ulcers. In single-step growth curves, the latency period of isolate 721 was 8 h while that of isolate 8665 was 6 h. The cytopathic effect produced by isolate 721 in bovine lung cells was characterized by enlargement of the cell, cell-to-cell adherence and large intracytoplasmic accumulations of viral inclusion material. Isolate 8665 caused rapid cell degeneration and detachment, with small accumulation of viral inclusion material. Neither of the two strains grew in bovine alveolar macrophage cultures or in the respiratory epithelium of fetal bovine tracheal explants. Intragingival inoculation of these isolates in cattle resulted in oral lesions without clinical signs of respiratory of systemic involvement. Virus was recovered from the oral lesions and from nasal secretions for as long as 10 days. Inoculation of dexamethasone-treated cattle resulted in a similar clinical condition although virus was recovered for 20 days from oral lesions and nasal secretions. Seroconversions from negative to 1 : 2560 were detected in inoculated cattle by indirect immunofluorescence.     

Mycobacterium bovis lipids: virulence and vaccines

The objective of this study was to determine the amount and infectivity of porcine circovirus type 2 (PCV2) shed in nasal, oral and fecal secretions following experimental infection. Fecal, oral and nasal swabs and blood were collected at regular intervals until 69 days post-inoculation (DPI) from five PCV2-experimentally inoculated pigs (Trial 1). To assess the infectivity of the PCV2 present in excretions, secretions, and on a hypodermic needle, 26 PCV2-na?ve pigs (Trial 2) were inoculated with various samples obtained from Trial 1 pigs. In Trial 1, PCV2 DNA was detected in all sample types by 69 DPI. There were no differences in the amount of PCV2 DNA present in different sample types over time. In Trial 2, intraperitoneal inoculation with contaminated fecal, nasal and oral samples; intranasal inoculation of nasal secretions; and feces fed to na?ve animals resulted in viremia and seroconversion. Viremia and microscopic lesions were noted in one animal injected using a contaminated needle. In conclusion, experimental PCV2 exposure results in a long term infection. PCV2 is shed in similar amounts by nasal, oral and fecal routes and is infectious to na?ve pigs confirming that multiple routes of transmission are likely important in spread of PCV2 between pigs.     

Negative-pressure pulmonary edema complicated by acute respiratory distress syndrome in an orangutan (Pongo pygmaeus abelii).

A 22-yr-old, 86-kg, morbidly obese female orangutan (Pongo pygmaeus abelii) was immobilized and transported to the Denver Zoological Gardens hospital for a routine physical examination. Immediately after arriving at the hospital, cyanosis and apparent inadequate ventilatory efforts were noted. Clinically significant hypoxia occurred despite attempts to ventilate the orangutan through face mask, and attempts to place an endotracheal tube began. A large volume of pink-tinged frothy fluid flowed from the trachea when the laryngoscope was inserted into the oropharynx. Severe pulmonary edema due to negative-pressure pulmonary edema, precipitating life-threatening hypoxia was suspected. The orangutan was maintained on a mechanical ventilator using the neuromuscular blocking agent cisatracurium besylate and sedation with periodic doses of isoflurane and midazolam for 48 hr. Positive end-expiratory pressure was used while the orangutan was ventilated mechanically to improve respiratory function. The edema and hypoxia improved, but respiratory arrest ensued 30 min after extubation, when the orangutan was removed from mechanical ventilation. Necropsy and histopathology demonstrated that serious lung injury had led to acute respiratory distress syndrome.     

Evaluation of the dermal effects of cast padding in coaptation casts on dogs.

Three configurations of cast padding and no cast padding were evaluated for their effects on skin in dogs. Padding was placed over bony prominences, between bony prominences, and over both areas for full-length padding under short-limb walking casts applied to 1 pelvic limb of Greyhounds. Evaluations were performed by pressure measurement over the calcaneal tuberosity, measurement of skin thromboxane B2 (TxB2) concentrations in skin over bony prominences, and measurement of plasma TxB2 concentrations. Pressure studies were performed to evaluate cutaneous pressures related to no cast padding and various configurations of cast padding. Concentrations of TxB2 in the skin were determined to evaluate the skin inflammatory effects of no padding and the padding configurations, and TxB2 concentrations in the plasma were analyzed to ascertain whether they could be used to predict impending dermal pressure lesions. Flexion of casted limbs revealed the greatest pressure over the calcaneal tuberosity with full-length cast padding. This was followed in decreasing order by no cast padding, padding over the prominences, and padding between the prominences. Compared with all other bony prominences and padding configurations, TxB2 skin concentrations were significantly higher over the calcaneal tuberosity when no padding was used and over the lateral base of metatarsal V when padding was placed between the prominences. Over the calcaneal tuberosity, this was attributed to the sharpness of the prominence and its potential for movement. This high TxB2 concentration corresponded to the high pressure found in the pressure studies. Over the lateral base of metatarsal V, the increase in TxB2 concentration was related to the mass of the prominence and the tendency for localized padding to settle around the area.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response of cattle persistently infected with bovine virus diarrhoea virus to bovine leukosis virus

Six cattle persistently infected with bovine virus diarrhoea virus (BVDV) and seronegative, and two control, virus negative seropositive cattle were inoculated with lymphocytes infected with bovine leukosis virus (BLV). The two controls produced a normal immune response to BLV, developing antibodies at four and five weeks after inoculation. Two of the six cattle persistently infected with BVDV developed a strong antibody response by six weeks after inoculation with BLV. Four developed a depressed response to BLV, characterised in three by a 'hooking' reaction in the immunodiffusion test which persisted in successive bleedings but was interspersed occasionally by a weak positive reaction. In one of these animals, a series of 'hooking' reactions was followed by a number of negative results. The fourth animal remained serologically negative until 16 weeks after inoculation when a 'hooking' reaction was observed followed by a series of negative results. BLV was isolated from all the cattle persistently infected with BVDV at 42 or 58 weeks after inoculation regardless of whether the serum samples gave negative, 'hooking', weak positive or positive reactions in the immunodiffusion test. BLV was consistently isolated from the nasal secretions of a steer which was BVDV negative but seropositive. The possibility of decreased immune responsiveness to BLV in animals persistently infected with BVDV should be considered when formulating regulations governing the testing of animals for freedom from BLV.     

Performance, survival, necropsy, and virological findings from calves persistently infected with the bovine viral diarrhea virus originating from a single Saskatchewan beef herd.

Fifty-one calves from 652 cows and heifers that calved on a Saskatchewan ranch in 1992 were identified as persistently infected with bovine viral diarrhea virus (BVDV), based on virological and necropsy findings. Herd records suggested a further 20 calves that died between birth and weaning were probably also persistently infected. Subsequent to weaning, all surviving persistently infected calves were transferred to one pen in a 10,000 head commercial feedlot, to mimic normal management practice in western Canadian beef herds. On average, when compared with healthy, BVDV-negative herdmates, persistently infected calves were "poor doers" and had poor survivability, with only 4 persistently infected calves surviving to 1 year of age. There was no difference (P > 0.05) in survival between male and female persistently infected calves. The clinical, pathological, and virological findings from these persistently infected calves varied over time. The majority of persistently infected calves had gross pathological lesions at necropsy, consistent with mucosal disease. However, approximately 25% of the persistently infected calves had gross pneumonic lesions at necropsy, with no or only mild lesions of mucosal disease. A wide variety of other lesions were also noted in persistently infected calves at necropsy. Therefore, the possibility that BVDV-induced lesions can be misdiagnosed is very real. The results of this study indicate that persistent infection with BVDV should always be considered in calves with chronic ill thrift, chronic enteritis, or respiratory disease.     

Endotracheal nebulization of N-acetylcysteine increases airway resistance in cats with experimental asthma

N-acetylcysteine (NAC), a mucolytic and antioxidant, is speculated to cause bronchoconstriction in cats when delivered via aerosol. We hypothesized that in cats with experimental asthma, aerosol delivery of NAC (400mg cumulative dose) via an endotracheal tube would increase airflow limitation as measured by ventilator-acquired mechanics. After endotracheal drug delivery, airway resistance and inspiratory plateau pressure (Pplat) measurements were obtained in six mechanically ventilated asthmatic cats. Results demonstrated significantly increased airway resistance (P=0.0007) compared with aerosolized saline control; Pplats were not significantly different (P=0.059). All cats exhibited at least one adverse effect: excessive airway secretions (n=3), spontaneous cough (n=2), unilateral strabismus (n=1) and post-anesthetic death (n=1). No adverse reactions were noted with saline aerosol; cough was noted in one cat with methacholine challenge. In conclusion, airway resistance and adverse reactions were documented in all cats after NAC aerosol delivery. Further studies must be performed to evaluate if it is an effective mucolytic and/or antioxidant in cats and to determine if bronchodilator pre-treatment will negate NAC-induced bronchoconstriction.     

Efficacy and safety field trials of a recombinant DNA vaccine against feline leukemia virus infection.

A new recombinant gp70 vaccine was found to be safe and effective for prevention of infection by FeLV. The vaccine incorporates a unique purified saponin adjuvant with the recombinant antigen. Serious systemic reactions were not observed during the efficacy trial. Local reactions were transient and mild. More than 2,000 doses were administered to a cross section of household cats in a field safety trial. Only 1 cat had hypersensitivity reaction, which resolved. Among veterinarians who used the vaccine and the cat owners, the vaccine was judged satisfactory and safe. After rigorous intraperitoneal challenge exposure without use of immunosuppressants, 100% of the controls in the efficacy trial became infected, 70% of which remained persistently infected with FeLV. Among vaccinates, 45% were never viremic and 40% cleared transient infection within 12 weeks after challenge exposure. Of the 20 vaccinated cats, 3 were persistently infected. Overall, 85% of cats vaccinated with this recombinant DNA FeLV vaccine resisted persistent FeLV infection after stringent challenge exposure, which translates to preventable fraction of 78.6%.     

Dorsal Displacement of the Soft Palate Secondary to Persistent Frenulum of the Epiglottis in Neonatal Foal

Dorsal displacement of the soft palate (DDSP) usually occurs in athletic adult horses. Congenital DDSP in foals secondary to the persistent frenulum of the epiglottis is rarely observed. The aim of this report was to describe a case of a seven-day-old female neonate Quarter Horse presenting dysphagia, milk reflux through the nostrils and mouth, and expiratory dyspnea since 4 days. Thoracic auscultation was indicative of aspiration pneumonia. Diagnosis of DDSP associated with local inflammation was made after endoscopic examination of upper respiratory tract. Radiographic examination was performed to rule out hypoplasia of the epiglottis. No clinical improvement was observed after anti-inflammatory treatment with flunixin meglumine. Oral endoscopy under general anesthesia revealed that the displacement of the soft palate was caused by a persistent frenulum of the epiglottis. Using a 30° rigid endoscope and a curved laparoscopic scissors, the frenulum was transected. After surgery, no dysphagia or dyspnea at rest was observed. However, discreet respiratory noise persisted during exercise for 5 days postoperatively. After discharge, the owner reported that the animal was completely normal during exercise. The animal is currently 3 years old and is developing a normal athletic performance. Persistent frenulum of the epiglottis should be considered while examining neonates with nasal milk reflux associated with expiratory dyspnea. This case report emphasizes the importance of the differential diagnosis for DDSP and for DDSP secondary to the persistent frenulum of the epiglottis in neonatal foals. It also underlines the importance of oral endoscopic examination for diagnosis.     

Synergistic inhibition of the growth in vitro of Microsporum canis by miconazole and chlorhexidine

An agar dilution technique was used to assess the minimum inhibitory concentrations (MIC) of miconazole, chlorhexidine and a 1:1 combination of both agents for 10 isolates of Microsporum canis. For nine of 10 of the isolates, a combination of miconazole and chlorhexidine was more effective than either agent alone; fractional inhibitory concentration indices indicated a synergistic effect for five isolates and an additive effect for four. These results illustrate the potent antimycotic effect of miconazole and chlorhexidine against M. canis and are in accordance with previous clinical studies that showed the value of using miconazole and chlorhexidine shampoo in association with oral griseofulvin in the treatment of feline dermatophytosis caused by M. canis.     

Indications and outcomes for puppies undergoing mechanical ventilation: 59 cases (2006 to 2020)

The medical records of 59 puppies from 6 hospitals undergoing mechanical ventilation (MV) between 2006 and 2020 were reviewed to describe the signalment, underlying disease, duration of ventilation, and outcome. The most common underlying diseases were pneumonia (n = 18), non-cardiogenic pulmonary edema (n = 16), and trauma (n = 8). Twenty-six (44%) puppies were weaned from the ventilator. The overall survival rate was 39% (23/59) including 19 non-brachycephalic dogs and 4 brachycephalics. Median duration of mechanical ventilation was 27 hours (range: 4 to 144 hours). Brachycephalic dogs were less likely to survive than nonbrachycephalic dogs (P = 0.032). English bulldogs were over-represented with pneumonia. No association between age and survival to discharge (P = 0.716) or outcome (P = 0.579) was detected. The survival rate, and underlying disease process and severity for mechanically ventilated puppies was similar to previous studies in adult dogs.