THE ROLE OF ULTRASOUND IN THE ASSESSMENT OF LARYNGEAL PARALYSIS IN THE DOG

Forty dogs with clinical signs suggestive of upper respiratory tract disease underwent echolaryngography and laryngoscopy. Laryngoscopy was used as the definitive technique to diagnose laryngeal paralysis. The ultrasound investigation accurately indicated the presence of the paralysis and confirmed the uni- or bilateral nature of the disorder. Findings indicative of laryngeal paralysis included asymmetry or absence of motion of the cuneiform processes (30/30), abnormal arytenoid movement (16/30), paradoxical movement (9/30), caudal displacement of the larynx (2/30) and laryngeal collapse (1/30). Thirty dogs were found to be afflicted with laryngeal paralysis and ten had normal laryngeal motility.     

Laryngeal paralysis in cats: 16 cases (1990-1999)

OBJECTIVE: To determine clinical signs, physical examination findings, radiographic features, and concurrent diseases in cats with laryngeal paralysis, as well as evaluate the outcome of medical or surgical management. DESIGN: Retrospective study. ANIMALS: 16 cats. PROCEDURE: Medical records from January 1990 to April 1999 were examined for cats with laryngeal paralysis. Signalment, clinical signs, physical examination findings, cervical and thoracic radiographic findings, laryngeal examination results, and clinical outcome were reviewed. RESULTS: No breed or sex predilection was identified in 16 cats with laryngeal paralysis. The most common clinical signs included tachypnea or dyspnea, dysphagia, weight loss, change in vocalization, coughing, and lethargy. Clinical signs were evident for a median of 245 days. Airway obstruction was apparent on cervical and thoracic radiographic views in 9 cats. Examination of the larynx revealed bilateral laryngeal paralysis in 12 cats and unilateral laryngeal paralysis in 4 cats. The 4 cats with unilateral disease were managed with medical treatment, and 3 of these had acceptable long-term outcomes. Seven of 12 cats with bilateral paralysis underwent surgery; procedures performed included left arytenoid tie back, bilateral arytenoid tie back and ventriculo-cordectomy, and partial left arytenoidectomy. One cat was euthanatized as a result of complications from surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Laryngeal paralysis is an uncommon cause of airway obstruction in cats. Cats with less severe clinical signs (often with unilateral paralysis) may be successfully managed with medical treatment, whereas cats with severe airway obstruction (often with bilateral paralysis) may benefit from surgical intervention.     

Comparison of Three Clinical Techniques for the Diagnosis of Laryngeal Paralysis in Dogs

Objectives— To evaluate laryngeal function using 3 diagnostic techniques: echolaryngography (EL), transnasal laryngoscopy (TNL), and laryngoscopy per os (LPO).
Study Design— Prospective clinical study.
Animals— Dogs with laryngeal paralysis (n=5) and control dogs (n=10); 5 age- and breed-matched dogs and 5 young, breed-matched dogs.
Methods— Laryngeal function was evaluated in conscious dogs using EL. All examinations were recorded and evaluated by separate, blinded observers upon completion of the study. The methods were compared with a standard evaluation incorporating all clinical knowledge of the case (STD) using sensitivity, specificity, positive, and negative predictive values.
Results— Three dogs with bilateral laryngeal paralysis requiring surgery were diagnosed as unilaterally affected or normal on EL. Three dogs had paradoxic motion on TNL and LPO, 2 of those were considered normal on EL, and 1 had no motion on EL. Paralysis was diagnosed in 1 age-matched and 3 young control dogs on EL. LPO and TNL falsely diagnosed lack of arytenoid movement in 2 age-matched controls and 1 young control. Two age-matched and 1 young control dog were misdiagnosed as paralyzed with TNL and LPO.
Discussion— Direct observation of the larynx allowed better evaluation of laryngeal function compared with EL. TNL did not require induction of anesthesia, but did not improve the ability to assess laryngeal function compared with LPO.
Conclusions— EL was not as effective as direct observation of the larynx. TNL did not improve the evaluation of laryngeal function compared with LPO.
Clinical Relevance— We use LPO combined with knowledge of the clinical history and physical examination to diagnose laryngeal paralysis in preference to EL and TNL.     

The effect of two modifications of unilateral arytenoid lateralization on rima glottidis area in dogs

OBJECTIVES: To evaluate the clinical outcome and percentage increase in rima glottidis area achieved using a combined technique of cricoarytenoid and thyroarytenoid cartilage lateralization compared with cricoarytenoid cartilage lateralization alone in live anesthetized dogs clinically affected with bilateral laryngeal paralysis. STUDY DESIGN: Randomized prospective clinical study. ANIMALS: Twenty dogs with bilateral laryngeal paralysis. Methods-Bilateral laryngeal paralysis was diagnosed by direct laryngoscopy. Each dog was allocated randomly to 1 of 2 surgical groups: CAL (cricoarytenoid lateralization) and CTAL (cricoarytenoid and thyroarytenoid lateralization). Photographs were taken of each larynx before and after surgery, the images were digitized, and the preoperative and postoperative areas of each rima glottidis were measured. The percentage increase in rima glottidis area produced by each of the arytenoid lateralization procedures was compared. Follow-up was obtained by telephone survey of owners and referring veterinarians. RESULTS: There was no significant difference in mean (+/- SD) percentage increase in rima glottidis area for the CAL group (241.5 +/- 42.9%) or the CTAL group (236.4 +/- 44.5%). Clinical follow-up (median, 18 months postoperatively) indicated 60% of the dogs were still alive and only 1 dog had died as a result of complications related to surgery. CONCLUSIONS: CTAL for the treatment of canine laryngeal paralysis does not significantly increase rima glottidis area compared with CAL alone. The mean percentage increase in rima glottidis area obtained with both procedures was comparable to previously reported mean increases with CAL in live anesthetized dogs. Both procedures resulted in good long-term clinical outcome. CLINICAL RELEVANCE: CTAL is as effective as CAL in providing an increased rima glottidis for the treatment of bilateral laryngeal paralysis in dogs.     

Arytenoid Lateralization for Treatment of Laryngeal Paralysis in 10 Cats

Objective— To describe the signalment, history, clinical signs, surgical technique, and outcome for cats with laryngeal paralysis that had arytenoid lateralization.
Study Design— Case series.
Animals— Cats with laryngeal paralysis (n=10).
Methods— Medical records (1996–2002) for cats with laryngeal paralysis that had arytenoid lateralization were reviewed for signalment, history, clinical signs, degree of paralysis, cause, concurrent medical conditions, surgical technique, and outcome. Follow-up information was obtained from owners or referring veterinarians.
Results— Of 10 cats, 9 had bilateral and 1 had unilateral laryngeal paralysis. Arytenoid lateralization were unilateral (n=7), bilateral (1), and staged bilateral procedures (2), 10 days and 3 years apart, respectively. Postoperatively, 1 cat had persistent inspiratory noise because of minimal enlargement of the rima glottidis and 2 cats required a temporary tracheostomy for management of laryngeal swelling. Three cats developed aspiration pneumonia and died 4, 7, and 150 days after surgery; all 3 had bilateral (simultaneous or staged) procedures. Of the 7 remaining cats, 4 were alive at follow-up and 3 had died of causes unrelated to arytenoid lateralization. The calculated mean survival time for all 10 cats was 406 days (median, 150 days; range, 4–1825 days).
Conclusions— Arytenoid lateralization was effective at enlarging the rima glottidis and reducing signs of airway obstruction in most cats.
Clinical Relevance— Unilateral arytenoid lateralization is a feasible option for the surgical management of cats with marked clinical signs; however, bilateral procedures should be avoided or at least performed with considerable caution because of the apparent risk for aspiration pneumonia.     

Physicochemical Interpretation of Acid‐Base Abnormalities in 54 Adult Horses with Acute Severe Colitis and Diarrhea

Background

The quantitative effect of strong electrolytes, pCO₂, and plasma protein concentration in determining plasma pH and bicarbonate concentrations can be demonstrated with the physicochemical approach. Plasma anion gap (AG) and strong ion gap (SIG) are used to assess the presence or absence of unmeasured anions.

Hypotheses

The physicochemical approach is useful for detection and explanation of acid‐base disorders in horses with colitis. AG and SIG accurately predict hyperlactatemia in horses with colitis.

Animals

Fifty‐four horses with acute colitis and diarrhea.

Methods

Retrospective study . Physicochemical variables were calculated for each patient. ROC curves were generated to analyze sensitivity and specificity of AG and SIG for predicting hyperlactatemia.

Results

Physicochemical interpretation of acid‐base events indicated that strong ion metabolic acidosis was present in 39 (72%) horses. Mixed strong ion acidosis and decreased weak acid (hypoproteinemia) alkalosis was concomitantly present in 17 (30%) patients. The sensitivity and specificity of AG and SIG to predict hyperlactatemia (L‐lactate > 5 mEq/L) were 100% (95% CI, 66.4–100; P < .0001) and 84.4% (95% CI, 70.5–93.5 P < .0001). Area under the ROC curve for AG and SIG for predicting hyperlactatemia was 0.95 (95% CI, 0.86–0.99) and 0.93 (95% CI, 0.83–0.99), respectively.

Conclusion and Clinical relevance

These results emphasize the importance of strong ions and proteins in the maintenance of the acid‐base equilibria. AG and SIG were considered good predictors of clinically relevant hyperlactatemia.     

Upper airway obstruction in canine laryngeal paralysis

The type and the severity of airway obstruction in 30 dogs with bilateral laryngeal paralysis was assessed, using tidal breathing flow-volume loop (TBFVL) analysis. The dogs had clinical evidence of mild-to-severe upper airway obstruction (ie, respiratory distress, exercise intolerance, stridor). Seventeen dogs had TBFVL consistent with a nonfixed (inspiratory) obstruction, 10 had TBFVL indicative of a fixed (inspiratory/expiratory) obstruction, and 3 had normal TBFVL. Analysis of TBFVL confirmed that dogs with laryngeal paralysis have upper airway obstruction that differs in type and severity. Use of TBFVL provided a quantitative evaluation of airway obstruction and demonstrated the effects of bilateral laryngeal paralysis on the breathing patterns of dogs.     

Advances in diagnostic imaging of the larynx and pharynx

Imaging of the larynx and pharynx has traditionally been limited to upper airway endoscopy and radiography. Recently, ultrasonography, magnetic resonance imaging and computed tomography have become used more widely. These modalities have increased our diagnostic yield when investigating disorders of the upper airway. The Case Report in this issue ( Koenig et al. 2012 ) describes the diagnosis and biopsy of a laryngeal mass using ultrasonography illustrating one novel application of laryngeal ultrasonography. Increased use of laryngeal ultrasonography and advanced imaging of the larynx and pharynx will hopefully lead to a better understanding of conditions of the upper airway and improved treatment strategies.     

Paralaryngeal Abscess with Laryngeal Hemiplegia and Fistulation in a Horse

A three year old Thoroughbred filly was examined because of bilateral nasal discharge and external swelling of the left laryngeal area. Endoscopy revealed an enlarged left arytenoid cartilage, left laryngeal hemiplegia and drainage of purulent material into the lumen of the larynx. Radiographs showed a large fluid and gas filled cavity overlying the caudal larynx and cranial trachea. Surgical drainage and debridement of the abscess led to complete healing by secondary intention. Laryngeal ventriculectomy was performed as a treatment for left laryngeal hemiplegia, but a grave prognosis for respiratory soundness was given due to the extensive laryngeal fibrosis. The etiology of the Staphylococcus aureus abscess is unknown but may have originated from oral trauma to the larynx.     

Computed tomographic evaluation of the distal limb in the standing sedated horse: Technique,imaging diagnoses,feasibility, and artifacts

In several veterinary institutions, adjustments of CT machines have been made that allow for imaging of the standing horse. The risk of general anesthesia is eliminated and the shorter scan completion time reduces cost to clients. The objective of this retrospective, analytical study was to evaluate the technique, imaging diagnoses, feasibility, and image artifacts of multi-slice helical CT of horses’ distal limbs acquired under standing sedation. The CT images of 250 horses of various breeds, aged 3–23 years, that underwent standing distal limb CT were evaluated. Three observers assessed the CT images for artifacts and inter-observer agreement was calculated. Eighty-six percent (95% confidence interval (CI), 81–90) of the scans were carried out on the forelimbs, while 14% (95% CI, 10–19) were of the hindlimbs. A total of 65% (95% CI, 59–71) of horses that underwent standing sedated CT had single imaging diagnoses. Seventy-one percent (95% CI, 65–77) of the cases had unilateral lesions, 27% (95% CI, 22–33) had bilateral lesions and 2% (95% CI, 1–4) had no diagnosed lesions. The average CT acquisition time was 17.5 minutes (range = 15–20). The average number of acquisitions per horse was 1.7 (median = 1; range = 1–4). There was good to excellent agreement between all three observers for the presence of motion artifact in the metacarpo/metatarsophalangeal joints, identification of marked beam hardening artifact, mild solar/ skin dirt, and photon starvation artifact (kappa 0.61-0.80). No complications were encountered. Standing examination of the distal limb achieved diagnostic image quality that was obtained with minimal acquisition attempts and in a timely manner.     

COMPUTED TOMOGRAPHIC IMAGING OF DOGS WITH PRIMARY LARYNGEAL OR TRACHEAL AIRWAY OBSTRUCTION

Seventeen dogs with clinical signs attributable to nonneoplastic obstruction of the larynx, trachea, or large bronchi underwent computed tomography (CT) imaging. In 16 of the 17 dogs, CT was performed without general anesthesia using a positioning device. Fifteen of these 16 dogs were imaged without sedation or general anesthesia. Three‐dimensional (3D) internal rendering was performed on each image set based on lesion localization determined by routine image planes. Visual laryngeal examination, endoscopy, video fluoroscopy, and necropsy were used for achieving the cause of the upper airway obstruction. The CT and 3D internal rendering accurately indicated the presence and cause of upper airway obstruction in all dogs. CT findings indicative of laryngeal paralysis included failure to abduct the arytenoid cartilages, narrowed rima glottis, and air‐filled laryngeal ventricles. Laryngeal collapse findings depended on the grade of collapse and included everted laryngeal saccules, collapse of the cuneiform processes and corniculate processes, and narrowed rima glottis. Trachea abnormalities included hypoplasia, stenosis, or collapse syndrome. The CT findings in tracheal hypoplasia consisted of a severely narrowed lumen throughout the entire length. Tracheal stenosis was represented by a circumferential decrease in tracheal lumen size limited to one region. Tracheal collapse syndrome was diagnosed by severe asymmetric narrowing. Lobar bronchi collapse appeared in CT images as a narrowed asymmetric lumen diameter. CT imaging of unanesthetized dogs with upper airway obstruction compares favorably with traditional definitive diagnostic methods.     

Experimental crush of the equine recurrent laryngeal nerve: a study of normal and aberrant reinnervation

Experimental reinnervation of the equine larynx in healthy ponies was studied after the recurrent laryngeal nerve was crushed, using endoscopic, electromyographic, and microscopic techniques. In 12 ponies, the recurrent laryngeal nerve was crushed unilaterally in the midcervical area. All showed postoperative paralysis of the larynx on the operated side. In 8 ponies, recovery of movement of the vocal folds occurred at different times (2.5 to 8 months) after surgical operation was done. These movements, which were often abnormal, included trembling and asynchronism. In 2 of these ponies, complete return of normal vocal fold function occurred. Return of function was due to reinnervation, as determined by electromyographic examination of the laryngeal muscles and microscopic evaluation of these muscles and the recurrent laryngeal nerves. In the muscles, there was evidence of fiber-type grouping, and the nerves showed regenerative activity. In 3 ponies, there was evidence of aberrant reinnervation, with adductor or abductor muscles discharging during an inappropriate phase of the respiratory cycle. Further evidence that reinnervation occurred in the larynges of these ponies was determined in microscopic sections of the recurrent laryngeal nerves and muscles, which showed regenerative activity and muscle fiber-type grouping, respectively. The endoscopic abnormalities in these ponies were compared with those seen in horses with spontaneous subclinical laryngeal paralysis. However, the possibility that the abnormal endoscopic findings in this latter group of horses are due to aberrant reinnervation is thought to be unlikely.     

Bilateral thyroarytenoid cartilage lateralization and vocal fold excision with mucosoplasty for treatment of idiopathic laryngeal paralysis: 67 dogs (1998-2005)

Objective— To evaluate combined bilateral thyroarytenoid cartilage lateralization, vocal fold excision, and mucosoplasty technique (BTAL) through ventral median laryngotomy for treatment of laryngeal paralysis in dogs.
Design— Retrospective study.
Animals— Dogs (n=67) with laryngeal paralysis.
Methods— Medical records were reviewed for dogs with idiopathic laryngeal paralysis that had BTAL between January 1998 and March 2005. Retrieved data included signalment, history, physical and laryngoscopic examination findings, clinicopathologic tests, and results of recheck examination findings.
Results— BTAL was performed by a single surgeon. Short-term (<6 months) follow-up information was available for 67 dogs and long-term (>12 months) for 40 dogs. Major postoperative complications were surgical failures (13; 7 short term, 6 long term) and aspiration pneumonia (1). Mean recurrence of clinical signs was at 19 weeks (range, 2–30 weeks). Minor complications occurred in 22 (33%) dogs including occasional coughing or gagging, stridorous breathing during exercise, panting, noisy or heavy breathing, and aspiration pneumonia (3 dogs) that did not require hospitalization. All owners reported an improved quality of life and had no regrets with surgical outcome.
Conclusions— BTAL is seemingly an effective procedure for treatment of laryngeal paralysis.
Clinical Relevance— BTAL is associated with a low incidence of aspiration pneumonia; however, there is substantial risk of recurrence of clinical signs associated with narrowing of the glottis. Consequently, unilateral arytenoid lateralization currently represents the accepted approach to the treatment of laryngeal paralysis.     

Solid‐Surface Vitrification and In‐Straw Dilution After Warming of In Vitro‐Produced Bovine Embryos

Three experiments were designed to test a solid‐surface vitrification system for bovine in vitro‐produced embryos and to develop a simple method of in‐straw dilution after warming, which can be potentially used for direct transfer in the field. Experiment 1 evaluated embryo survival rates (i.e. re‐expansion and hatching) after vitrification and warming in three different solutions: VS1 (20% ethylene glycol (EG) + 20% propanediol (PROH) + 0.25 m trehalose (Tr)), VS2 (20% EG + 1M Tr) or VS3 (30% EG + 0.75 m Tr). Re‐expansion and hatching rates were higher (p < 0.05) for embryos vitrified in VS3 (72.2 ± 1.9 and 58.2 ± 0.8) than VS1 (64.4 ± 0.9 and 37.2 ± 2.5) or VS2 (68.5 ± 1.5 and 49.6 ± 1.0; p < 0.05). Experiment 2 was designed to compare two methods of vitrification: glass micropipettes or solid surface, using the VS1 or VS3 solutions. No significant differences were detected between the two methods; but re‐expansion and hatching rates were higher (p < 0.05) with VS3 (73.5 ± 3.1 and 47.1 ± 2.1) than VS1 (63.3 ± 3.3 and 39.7 ± 2.8). In experiment 3, embryos were vitrified by solid surface in VS1 or VS3 solutions and cryoprotectants were diluted in‐straw after warming in a TCM 199, 0.25 m sucrose solution or holding media. Survival rates of embryos vitrified in VS3 did not differ between those exposed to 0.25 m sucrose (74.7 ± 1.3 and 57.2 ± 2.2) or holding (77.3 ± 1.4 and 58.0 ± 2.5) medium after warming; however, survival rates of embryos vitrified in VS1 were higher (p < 0.05) in those exposed to 0.25 m sucrose (67.7 ± 2.3 and 47.0 ± 1.7) than holding medium (54.5 ± 1.0 and 27.7 ± 3.1). In conclusion, solid‐surface vitrification using simplified EG‐based solutions and in‐straw dilution with holding media may be a practical alternative for cryopreservation and direct transfer of in vitro‐produced bovine embryos.     

Unilateral arytenoid lateralisation for the treatment of laryngeal paralysis in four cats

A unilateral arytenoid lateralisation procedure was successfully performed in four cats with either unilateral or bilateral laryngeal paralysis. All of the cats were presented for the investigation of signs of exercise-related respiratory embarrassment and stridor. Other clinical signs seen included altered vocalisation, an inability to purr, coughing and lethargy. A diagnosis of either bilateral or left or right unilateral laryngeal paralysis was made in each case following visual inspection of the vocal folds with the aid of a laryngoscope under a light plane of anaesthesia. In two cases the paralysis was bilateral and the condition was considered to be either congenital or idiopathic. In the other two cases the condition was unilateral and was considered to be iatrogenic as a result of previous surgical procedures. The results of this technique were considered excellent in all cases.     

Evaluation of shock waveform configuration on the defibrillation capacity of implantable cardioverter defibrillators in dogs

BackgroundImplantable cardioverter defibrillators (ICD) are programmed to detect ventricular arrhythmias and terminate them by delivering an electrical shock. A defibrillation threshold (DFT) at least 10 J below the maximum device output is recommended for successful therapy. Shock waveform configuration is a programmable parameter used to achieve a low DFT. It is hypothesized that a fixed-pulse configuration results in lower defibrillation energy requirements than a fixed-tilt configuration.Animals10 mongrel dogs.Materials and methodsICD generator and transvenous lead were surgically implanted. Defibrillation threshold was determined using a protocol guided by the upper limit of vulnerability. Fixed-pulse and fixed-tilt (50%/50%) waveform configurations were tested in a random order. Plasma cardiac troponin I (cTnI) was measured for signs of myocardial injury.ResultsThe experiment was completed in 9 dogs. Overall mean DFT value was 424 ± 88 V (9.2 ± 3.9 J). Mean differences among voltage, energy and impedance at the DFT for fixed-pulse (422 ± 97 V, 9.1 ± 4.2 J, 62.6 ± 13.8 Ω) and fixed-tilt (426 ± 83 V, 9.3 ± 3.8 J, 62.8 ± 18.5 Ω) configurations were not statistically significant (All P > 0.21). Cardiac TnI concentration changed from 0.03 ng/mL (95% CI: 0.02–0.04) at baseline to 0.11 ng/mL (95 CI: 0.08–0.16) after DFT was obtained with the first waveform configuration and 0.19 ng/mL (95% CI: 0.13–0.28) at the end of the study period. There were no significant changes in heart rate, end-tidal CO2 and blood pressure over time (all P > 0.09).ConclusionThe tested ICD device and lead placement reliably produced acceptable DFT values, based on a 10-J safety margin below the maximum device output. A benefit of fixed-pulse configuration could not be demonstrated over the standard fixed-tilt waveform. Signs of acute myocardial damage from repeated high-voltage shocks and episodes of ventricular fibrillation seemed of limited clinical significance.     

Laryngeal paralysis in dogs: An evaluation of the bilateral arytenoid lateralisation procedure

Within the past decade, the number of reported cases of laryngeal paralysis in dogs has increased markedly. The disease is characterised by laryngeal obstruction caused by the inadequate abduction and instability of the arytenoid cartilages, aryepiglottic folds and vocal cords. Therefore, surgery performed to alleviate the clinical signs should ideally aim to reduce the airway obstruction and to prevent dynamic collapse. This paper presents the effectiveness of bilateral arytenoid lateralisation in 19 dogs with bilateral laryngeal paralysis. The procedure was effective in alleviating the clinical signs of laryngeal obstruction in all 19 dogs, with most surviving for several years. Postoperative laryngoscopic observations showed that the arytenoid cartilages were held in a satisfactory abducted position. A comparison of PaO₂ values before and after surgery demonstrated a significant (P 0·001) fall in the PaO₂ measurement between the pre- and postoperative blood samples. Postoperative complications included suture prosthesis failure in two dogs and a single non-fatal incident of aspiration pneumonia in two dogs.     

Evaluation of a modified castellated laryngofissure for alleviation of upper airway obstruction in dogs with laryngeal paralysis

A modified castellated laryngofissure procedure (castellated laryngofissure, vocal fold resection, and bilateral arytenoid lateralization) was performed on 12 dogs with bilateral laryngeal paralysis. Clinical signs of airway obstruction were assessed and a pulmonary function test (tidal breathing flow volume loop) was used to evaluate the severity of obstruction. The dogs were evaluated before surgery and at various periods from 4 days to 15 months after surgery. One dog died immediately after surgery and 3 dogs died due to nonrelated or unknown causes 1, 9, and 11 months after surgery. Clinical signs of upper airway obstruction disappeared or decreased in severity in the 11 dogs that recovered from surgery. Tidal breathing flow volume loop values were normal in 7 of 10 dogs evaluated within 5 to 189 days after surgery. The modified castellated laryngofissure procedure provided successful long-term relief of upper airway obstruction associated with bilateral laryngeal paralysis.     

Seroprevalence of <Emphasis Type="Italic">Neospora caninum</Emphasis> antibodies in beef cattle in three southern states of Mexico

The aims of the present study were to examine the seroprevalence of neosporosis in beef herds from three southern states of Mexico and determine the association with several risk factors. A cross-sectional serological survey for Neospora caninum was carried out by sampling a total of 596 animals from 31 herds in Chiapas, Veracruz, and Yucatan States and tested using an ELISA assay (IDEXX) to detect anti-N. caninum antibodies. The overall prevalence was 11.6%, (95% CI: 0.93–0.14), however, the prevalence for Chiapas was 15% (30/200) (95% CI: 0.11–0.21), in Yucatan 11.3% (21/186) (95% CI: 0.07–0.17) and in Veracruz 8.6% (18/210) (95% CI: 0.05–0.13). Of the 596 serum samples taken, 578 were from females and 18 were bulls., Only one bull sample was found seropositive from one herd in Veracruz State. The overall herd-prevalence was 70.9% (22/31) (95% CI: 0.53–0.84), and by State was: Chiapas 90% (9/10) (95% CI: 0.60–0.98); Yucatan 72.7% (8/12) (95% CI: 0.39–0.86); and Veracruz 50% (5/10) (95% CI: 0.24–0.76), respectively. The highest age-prevalences were found in animals 1 yr old (19.4% [95% CI: 0.01–0.35]) and 4 yrs old (19.6% [95% CI: 0.12–0.29]), and the lowest in animals 3 –yrs of age (6.2%,[95% CI: 0.02–0.20]). No association was found among all the variables tested in this study since most of the ranches have similar management conditions. In conclusion, N. caninum infection is common among beef herds in the Mexican tropics.     

Management factors affecting the risk for vesicular stomatitis in livestock operations in the western United States.

OBJECTIVE: To identify management factors affecting the risk of animals developing vesicular stomatitis (VS). DESIGN: Case-control study. ANIMALS: Horses, cattle, and sheep with suspected vesicular stomatitis on 395 premises in Colorado, New Mexico, Utah, and Arizona. PROCEDURE: Data were collected during the VS outbreak of 1997. Diagnosticians interviewed livestock owners and completed a supplemental questionnaire. Cases were defined as those premises that had a completed questionnaire and had > or = 1 animal positive for VS. Control premises were all premises investigated that had a completed questionnaire and on which the animals had been tested but VS was not detected. RESULTS: Animals that had access to a shelter or barn had a reduced risk of developing VS (OR, 0.6; 95% confidence interval [CI], 0.35 to 0.99). This effect was more pronounced for equine premises (OR, 0.5; 95% CI, 0.3 to 0.9). Conversely, during an adjusted analysis on equine premises, risk of developing disease was increased slightly where animals had access to pasture (OR, 2.01; 95% CI, 1.1 to 3.7). On all premises where owners reported insect populations were greater than normal, odds of developing disease were significantly increased (OR, 2.5; 95% CI, 1.47 to 4.47). Premises with animals housed < 0.25 miles from running water were more than twice as likely to have clinical signs of VS (OR, 2.6; 95% CI, 1.32 to 5.0). CONCLUSIONS AND CLINICAL RELEVANCE: These results support reports of others that suggest biting insects are a vector in VS virus transmission. Management practices to reduce exposure to biting insects might reduce the risk of VS.