Table of Contents and AbstractsJanuary 2017, Vol. 81, No. 1


Induction of humoral immune response in piglets after perinatal or post-weaning immunization against porcine circovirus type-2 or keyhole limpet hemocyanin

Jessica Law, UCVM Class of 2015*, Robert McCorkell, Greg Muench, Katherine Wynne-Edwards, Hermann M. Schaetzl, Cristina Solis, Narges Nourozieh, Regula Waeckerlin, Michael Eschbaumer, Shawn Horsman, Markus Czub (page 5)

The objective of this study was to test the hypothesis that porcine circovirus type-2 (PCV2) vaccination is efficacious when administered in the first week of life. Three groups of pigs were vaccinated with Circumvent either early (at the end of week 1), late (at the end of week 4), or not at all. All 3 groups were later challenged intranasally with PCV2 (at the end of week 5). Two other groups were immunized with keyhole limpet hemocyanin (KLH) as a novel antigen at the end of either week 1 or week 4. Weight, PCV2 genome copy number in serum and saliva, anti-KLH antibody titer, and serum PCV2-neutralizing antibodies were measured weekly. Early PCV2 vaccination or KLH antigen exposure resulted in earlier humoral responses that were slower to develop than in older piglets, yet converged with the responses to later vaccination within 5 wk. Both groups of vaccinated piglets had periods of higher PCV2-neutralizing antibody titers and lower viral levels shortly after weaning and PCV2 challenge, thus supporting the recent labelling of 1 Canadian PCV2 vaccine for use in week 1 and suggesting that early PCV2 vaccination can reduce piglet handling without compromising vaccine efficacy.

Evaluation of the new commercial recombinant chimeric subunit vaccine PRRSFREE in challenge with heterologous types 1 and 2 porcine reproductive and respiratory syndrome virus

Jiwoon Jeong, Changhoon Park, Kyuhyung Choi, Chanhee Chae (page 12)

The objective of this study was to evaluate a new recombinant chimeric vaccine against porcine reproductive and respiratory syndrome virus (PRRSV). The subunit vaccine, PRRSFREE, from Reber Genetics, Taiwan, Republic of China, is based on a plasmid containing a detoxified Pseudomonas exotoxin carrying open reading frame (ORF) 7, 1b, and 5 and 6 chimeric subunits of types 1 and 2 PRRSV. Pigs were injected intramuscularly with 2.0 mL of the vaccine at 21 and 42 d of age, according to the manufacturer's recommendation. At the age of 63 d the pigs were inoculated intranasally with either type 1 or type 2 PRRSV. Regardless of the genotype of the challenging PRRSV, the vaccinated challenged pigs had significantly lower (P < 0.05) mean rectal temperature, respiratory score, lung lesion score, and amount of PRRSV antigen within areas of interstitial pneumonia, along with overall lower levels of viremia due to type 1 or type 2 PRRSV compared with the unvaccinated challenged pigs. The vaccinated challenged pigs also had significantly higher (P < 0.05) numbers of interferon-γ secreting cells compared with the unvaccinated challenged pigs. This study demonstrated that the new vaccine provides protection against respiratory disease from heterologous types 1 and 2 PRRSV challenge in growing pigs.

Analysis of efficacy obtained with a trivalent inactivated Haemophilus parasuis serovars 4, 5, and 12 vaccine and commercial vaccines against Glässer's disease in piglets

Zhanqin Zhao, Huisheng Liu, Yun Xue, Kunpeng Chen, Zhijun Liu, Qiao Xue, Chen Wang (page 22)

The objective of this study was to assess the efficacy of a trivalent inactivated Haemophilus parasuis serovars 4, 5, and 12 vaccine with polymeric adjuvant gel (GEL) and commercial vaccines against Glässer's disease in piglets. Commercial vaccines containing inactivated H. parasuis serovars 4 and 5 (China), inactivated H. parasuis serovars 1 and 6 (Spain), and inactivated H. parasuis serovar 5 (USA) were also evaluated. Our results demonstrated that the trivalent inactivated H. parasuis serovars 4, 5, and 12 vaccine with GEL adjuvant can provide better protection against the 3 most common pathogenic serovars circulating in China than other commercial vaccines tested. Our findings also indicated that inactivated H. parasuis serovars 1 and 6 vaccine cross-protects piglets against H. parasuis serovars 4 and 5; inactivated H. parasuis serovar 5 vaccine cross-protects piglets against H. parasuis serovar 4 challenge; but none of the commercial vaccines tested in this study protected piglets against H. parasuis serovar 12. Our results provide a basis for further identification of common protective antigens that can induce cross-protection against heterogeneous serovars.

Phylogenetic analysis of Escherichia coli isolated from broilers with colibacillosis based on gyrA gene sequences

Hamid Shamsi, Karim Mardani, Abdolghaffar Ownagh (page 28)

Escherichia coli isolates from chickens with colibacillosis were assigned to phylogenetic groups based on multiplex polymerase chain reaction (PCR) and antibacterial resistance of E. coli belonging to these groups was examined. Furthermore, the gyrA gene of isolates was sequenced and a phylogenetic tree was generated. A total of 84 E. coli isolates were grouped using multiplex PCR of TSPE4.C2, chuA, yjaA, and gadA molecular markers. Four phylogenetic groups were identified with strains divided as follows: 16 in group A (19.05%), 17 in group B1 (20.24%), 23 in group B2 (27.38%), and 28 in group D (33.33%). Escherichia coli isolates belonging to phylogenetic groups B2 and D were resistant to Soltrim and Flumequine unlike the majority of E. coli isolates that belonged to groups A and B1, and which were susceptible to these antibiotics. The phylogenetic results based on gyrA gene sequences from multiplex PCR revealed that E. coli phylogenetic grouping was in accordance with the clusters obtained in the phylogenetic tree. In conclusion, the comparative sequence analysis of gyrA sequences provides a firm framework for an accurate classification of E. coli and related taxa and may constitute a pertinent phylogenetic marker for E. coli.

Antiviral activity of a novel composition of peracetic acid disinfectant on parvoviruses

Fadi Dagher, Jun Jiang, Peter Tijssen, Jean-François Laliberté (page 33)

Porcine parvoviruses (PPV) are known to be particularly resistant to many disinfectants used to control other non-enveloped viruses. However, effective disinfectants used against PPV are harsh and corrosive to animal health facilities and the environment. We propose a noncorrosive "green" disinfectant that generates peracetic acid in-situ and is capable of inactivating PPV completely at a 1% concentration for a 10-minute contact time.

Evaluation of serum myeloperoxidase concentration in dogs with heart failure due to chronic mitral valvular insufficiency

Jong-In Park, Sang-IL Suh, Changbaig Hyun (page 37)

Myeloperoxidase (MPO) is a leukocyte-derived enzyme involved in the process of heart failure and is found to have good diagnostic and prognostic values in humans with chronic heart failure. This study evaluated the relationship between serum MPO levels and the severity of heart failure (HF) due to chronic mitral valvular insufficiency (CMVI) in dogs. Eighty-two client-owned dogs consisting of 69 dogs with different stages of HF due to CMVI and 13 age-matched healthy dogs were enrolled in this study. Serum MPO concentrations in the healthy and CMVI groups were determined by enzyme-linked immunosorbent assay (ELISA) using a canine-specific monoclonal anti-MPO antibody. Serum MPO concentrations were 273.3 ± 179.6 ng/L in the controls, 140.8 ± 114.1 ng/L in the International Small Animal Cardiac Health Council (ISACHC) I group, 109.0 ± 85.2 ng/L in the ISACHC II group, and 106.0 ± 42.3 ng/L in the ISACHC III group. Close negative correlation to serum MPO concentration was found in the severity of heart failure (ISACHC stage). Although this study found a modest relationship between serum MPO levels and the severity of HF due to CMVI in dogs, it also suggested that serum MPO levels decreased as the severity of HF increased.

The effects of oral administration of Yunnan Baiyao on blood coagulation in beagle dogs as measured by kaolin-activated thromboelastography and buccal mucosal bleeding times

Jami Frederick, Søren Boysen, Catherine Wagg, Serge Chalhoub (page 41)

We examined the effects of oral administration of Yunnan Baiyao (YB) on hemostasis by measuring buccal mucosal bleeding times (BMBTs) and doing citrated kaolin-activated whole-blood thromboelastography (TEG). In a randomized controlled crossover trial 8 beagle dogs were given either placebo or 1000 mg of YB orally every 12 h for 5 consecutive treatments. Blood was drawn 24 h before treatment and 2 and 24 h after the last treatment, and the BMBT was measured in each sample in duplicate. The TEG analysis was done in duplicate 60 ± 5 min after sample collection. There were no adverse effects of treatment and no significant differences between the control and treatment BMBTs or TEG parameters at any time point. Significant differences were found between baseline and 24 h after the last treatment within the treatment group for the TEG parameters LY30 and LY60 and within the control group for the TEG parameters MA, G, LY30, and LY60. Thus, at the dose and frequency of administration in this study YB did not appear to have any clinically significant effects on the measured coagulation parameters. The differences within the treatment group were likely due to analytic error since similar differences were seen in the control group. Further studies with a larger sample, as well as more direct measures of platelet function, are needed.

Association of gingivitis with dental calculus thickness or dental calculus coverage and subgingival bacteria in feline leukemia virus- and feline immunodeficiency virus-negative cats

Naris Thengchaisri, Jörg M. Steiner, Jan S. Suchodolski, Panpicha Sattasathuchana (page 46)

Periodontal disease is the most common oral disease in cats. The objectives of this study were to determine the relationships between gingivitis and dental calculus thickness (DCT), or dental calculus coverage (DCC); determine the association of gingivitis scores and types of oral bacteria; and to evaluate bacterial co-infection in cats with periodontal disease. Twelve cats that were not infected with feline leukemia or feline immunodeficiency viruses were enrolled in the study. Gingivitis, DCT, and DCC were scored and recorded. A Kruskal-Wallis test was used to compare scores among canine, 2nd premolar, 3rd premolar, 4th premolar, and 1st molar teeth. The relationship between gingivitis and DCT or DCC scores was determined using the Spearman rank sum test (ρ). Subgingival bacteria were cultured and the association between bacterial species and gingivitis score was evaluated using a Fisher's exact test. The average gingivitis, DCT, and DCC scores for the caudal maxillary teeth were higher for the caudal mandibular teeth and more severe for the 3rd premolar, 4th premolar, and 1st molar teeth than for the canine teeth. A strong relationship between average DCT or DCC score and average gingivitis score was found (ρ = 0.96 and 1, respectively). Aerobic and anaerobic bacterial infections were identified in a large number of cats with periodontal disease (71.1% and 28.9%, respectively). In conclusion, severe gingivitis scores were associated with anaerobic bacterial infection. The caudal teeth are affected with more severe gingivitis, DCT, and DCC than the other teeth. Antibiotic prophylaxis should be prescribed in cats with periodontal disease.

Computed tomographic assessment of a new nonsurgical sinus trephination technique using a medical bone marrow drill

Victor Caudal, Elisabeth C. Snead, Gregory S. Starrak, Suresh Sathya, Cindy X. Feng (page 53)

The objective of this study was to determine the feasibility of trephination of the frontal sinus and injection of antifungal cream using a medical bone marrow drill in dogs. Results were compared with frontal sinus trephination using a standard surgical technique. Bilateral trephination of the frontal sinuses was carried out in the heads of 11 cadavers using a medical bone marrow drill and a surgical bone chuck. The time taken to carry out the procedure using both techniques was compared. Before and after injection of antifungal cream into the frontal sinuses, computed-tomography (CT) scanning was done to assess for iatrogenic trauma and to determine the degree to which the sinuses were filled with each technique and evaluate the diffusion of the cream into the nasal cavity of each dog. The mean volume of the sinuses was 8.8 mL (3.1 to 14.3 mL). Trephination, flushing, and injecting of antifungal cream were significantly faster using the medical technique. There was no significant difference in the mean filling of the frontal sinuses between the medical (82.7%) and the surgical (82.4%) technique (P-value = 0.3). Filling of the nasal cavity was classified as very good in 6/11 cases, with evidence of trauma caused by the surgical trephination technique in 1 head. Findings suggest that use of the medical bone marrow drill is highly feasible for frontal sinus trephination. Injection of antifungal cream into the frontal sinuses using the bone marrow needle resulted in good diffusion into the ipsilateral nasal cavity and could be used to treat aspergillosis when debridement or sinusoscopy is not deemed necessary.

Nasopharyngeal temperature measurement in sheep during general anesthesia

Tabita Tan, Jonathon Tuke, Gabrielle C. Musk (page 64)

The aim of this study was to compare nasopharyngeal and esophageal temperature measurements in anesthetized sheep with a range of fresh gas flows (1 to 6 L/min) through the breathing system. Data were compared using a Bland-Altman plot and correlation coefficients, and error measures were calculated. One hundred and ninety-five sets of data were collected from 20 sheep weighing 41 kg (31 to 51.5 kg). The bias (95% limit of agreement), correlation coefficient, and absolute error for nasopharyngeal compared to esophageal temperature were 0.04°C (-0.77°C to 0.85°C), 0.92, and 0.29°C ± 0.29°C, respectively. The percentage of nasopharyngeal readings within 0.5°C of the esophageal temperature was 77.44%. The error did not significantly increase with increasing fresh gas flow. Nasopharyngeal temperature measurement is suitable for estimation of esophageal temperature during general anesthesia of sheep when the fresh gas flow through the breathing system is between 1 and 6 L/min.

Characterization and therapeutic application of canine adipose mesenchymal stem cells to treat elbow osteoarthritis

Éva Kriston-Pál, Ágnes Czibula, Zoltán Gyuris, Gyula Balka, Antal Seregi, Farkas Sükösd, Miklós Süth, Endre Kiss-Tóth, Lajos Haracska, Ferenc Uher, Éva Monostori (page 73)

Visceral adipose tissue (AT) obtained from surgical waste during routine ovariectomies was used as a source for isolating canine mesenchymal stem cells (MSCs). As determined by cytofluorimetry, passage 2 cells expressed MSC markers CD44 and CD90 and were negative for lineage-specific markers CD34 and CD45. The cells differentiated toward osteogenic, adipogenic, and chondrogenic directions. With therapeutic aims, 30 dogs (39 joints) suffering from elbow dysplasia (ED) and osteoarthritis (OA) were intra-articularly transplanted with allogeneic MSCs suspended in 0.5% hyaluronic acid (HA). A highly significant improvement was achieved without any medication as demonstrated by the degree of lameness during the follow-up period of 1 y. Control arthroscopy of 1 transplanted dog indicated that the cartilage had regenerated. Histological analysis of the cartilage biopsy confirmed that the regenerated cartilage was of hyaline type. These results demonstrate that transplantation of allogeneic adipose tissue-derived mesenchymal stem cells (AT-MSCs) is a novel, noninvasive, and highly effective therapeutic tool in treating canine elbow dysplasia.

Brief Communications

Escherichia coli isolated from feces of brown bears (Ursus arctos) have a lower prevalence of human extraintestinal pathogenic E. coli virulence-associated genes

Maruša Vadnov, Damjana Barbic, Darja Žgur-Bertok, Marjanca Starcic Erjavec (page 59)

Eighty-six Escherichia coli strains from feces of either wild brown bears or those living in a zoo were screened for phylogenetic groups using the revisited Clermont phylotyping method and the prevalence of 24 virulence-associated genes (VAGs) of extraintestinal pathogenic E. coli (ExPEC). Our results showed that most strains of E. coli in bears belonged to phylogenetic groups III/IV/V (29%) and B1 (26%). Only half of the tested VAGs were found in the E. coli bear strains, with fimH present in 72%, ompT in 63%, and kpsMT in 43% of the strains. When the data obtained on the fecal E. coli strains from brown bears were compared with the data obtained on 90 fecal E. coli strains from healthy humans, there were significant differences in E. coli population structures between both hosts.

Cleaning with a wet sterile gauze significantly reduces contamination of sutures, instruments, and surgical gloves in a ex-vivo pelvic flexure enterotomy model in horses

Gessica Giusto, Clara Tramuta, Vittorio Caramello, Francesco Comino, Patrizia Nebbia, Patrizia Robino, Ellen Singer, Elena Grego, Marco Gandini (page 69)

The objective of this study was to investigate whether cleaning surgical materials used to close pelvic flexure enterotomies with a wet sterile gauze will reduce contamination and whether the use of a full thickness appositional suture pattern (F) or a partial thickness inverting (or Cushing) suture pattern (C) would make a difference in the level of contamination. Large colon specimens were assigned to group F or C and divided into subgroups N and G. In group G, a wet sterile gauze was passed over the suture material, another over the instruments, and another over the gloves. In group N, no treatment was applied. The bacterial concentration was measured by optical density (OD) at 24 h. The OD of subgroup CG was lower than that of subgroup CN (P = 0.019). The OD of subgroup FG was lower than that of subgroup FN (P = 0.02). The OD of subgroups CG, CN, FG, and FN was lower than that of the negative control (P < 0.003, P < 0.001, P < 0.001, and P < 0.00). The use of a sterile wet gauze significantly reduced contamination of suture materials. A partial thickness inverting suture pattern did not produce less contamination than a full thickness appositional suture pattern.