Ten years of Taylorella equigenitalis ring trial results comparing culture and polymerase chain reaction.

Taylorella equigenitalis, the cause of contagious equine metritis (CEM), can be detected by culture but in recent years polymerase chain reaction (PCR) has also been used. In 2008, the World Organisation for Animal Health (OIE) Reference Laboratory for CEM in the United Kingdom set up a ring trial for laboratories to assess their ability to identify T. equigenitalis in laboratory-prepared samples because the identification of T. equigenitalis in the laboratory was recognised to be difficult. Freeze-dried culture suspensions in various combinations of any of T. equigenitalis, Taylorella asinigenitalis, other typical equine contaminant organisms, or no organism were used. All laboratories provided culture results and some also gave PCR results. The results reported here cover the ten years since inception and look at the ability to identify T. equigenitalis under ideal laboratory conditions, a necessity to be able to detect its presence in equine genital samples. The detection rate was very high by both methods. The accuracy was not significantly different between the culture and PCR methods for pure T. equigenitalis samples. For T. equigenitalis mixed with contaminants, culture missed about 2% (p = 0.02) compared with PCR, which was over 99% accurate. Difficulty in differentiating T. asinigenitalis from T. equigenitalis was apparent in a number of laboratories for both culture and PCR in 2008 but was less evident in 2016. It was also noted that culture results from laboratories that also tested by PCR had around 4% higher detection rates (p < 0.05) of T. equigenitalis than those that only used culture.

La détection de Taylorella equigenitalis, l'agent causal de la métrite contagieuse équine, peut être réalisée par culture, mais aussi, depuis quelques années, par amplification en chaîne par polymérase (PCR). En 2008, le Laboratoire de référence de l'Organisation mondiale de la santé animale (OIE) pour cette maladie au Royaume-Uni a conçu une série d'essais comparatifs inter-laboratoires visant à évaluer la capacité des laboratoires à identifier des échantillons préparés de T. equigenitalis, compte tenu de la difficulté avérée de cette identification au laboratoire. Les essais ont porté sur des cultures lyophilisées en suspension contenant, dans diverses combinaisons, T. equigenitalis, Taylorella asinigenitalis, d'autres micro-organismes pathogènes des équidés, ou aucun agent pathogène. Tous les laboratoires participants ont communiqué les résultats des mises en culture et certains ont également transmis les résultats obtenus par PCR. Les résultats rapportés par les auteurs couvrent les dix années écoulées depuis le lancement des essais et visent à déterminer la capacité à identifier T. equigenitalis dans des conditions de laboratoire idéales, exigence essentielle pour pouvoir détecter la présence de cette bactérie à partir de prélèvements génitaux d'équidés. Le taux de détection s'est révélé très élevé pour chacune des deux méthodes. Il n'a pas été observé de variation significative entre l'exactitude de la mise en culture et celle de la PCR lorsque les prélèvements ne contenaient que T. equigenitalis. S'agissant de suspensions où T. equigenitalis était mélangée à d'autres agents pathogènes, les résultats font état d'environ 2 % (p = 0,02) d'échecs de l'identification par culture, tandis que l'exactitude de la PCR était de 99 %. En 2008, plusieurs laboratoires ont manifestement eu des difficultés à différencier T. asinigenitalis de T. equigenitalis aussi bien en culture que par PCR, mais cette difficulté était moins perceptible en 2016. Il a également été constaté que les identifications après culture effectuées par les laboratoires qui testaient aussi par PCR se traduisaient par un taux de détection de T. equigenitalis supérieur d'environ 4 % (p < 0,05) par rapport aux laboratoires qui ne pratiquaient que la mise en culture.

Taylorella equigenitalis, patógeno causante de la metritis contagiosa equina, puede ser detectado por cultivo, pero en los últimos años también se viene utilizando la técnica de reacción en cadena de la polimerasa (PCR). En 2008, ante la sabida dificultad que presenta la identificación en laboratorio de T. equigenitalis, el Laboratorio de Referencia de la Organización Mundial de Sanidad Animal (OIE), para esta enfermedad sito en el Reino Unido, puso en marcha una serie de pruebas de competencia para evaluar la aptitud de diferentes laboratorios para detectar la presencia de T. equigenitalis en muestras preparadas en laboratorio, empleando al efecto suspensiones de cultivo liofilizado con diversas combinaciones en las que estaban presentes T. equigenitalis, Taylorella asinigenitalis, otros patógenos equinos típicos o ningún microorganismo en absoluto. Todos los laboratorios comunicaron los resultados de las técnicas de cultivo y algunos de ellos también proporcionaron los resultados obtenidos por PCR. Los resultados aquí expuestos cubren los diez años transcurridos desde el inicio de las pruebas y dan cuenta de la capacidad para identificar a T. equigenitalis en condiciones de laboratorio idóneas, elemento imprescindible para poder detectar su presencia en muestras genitales equinas. Con ambos métodos se obtenía una tasa de detección muy elevada, sin que hubiera una diferencia de exactitud significativa entre el cultivo y la PCR en el caso de muestras puras de T. equigenitalis. Cuando este microorganismo estaba mezclado con contaminantes, «escapaban¼ al método de cultivo alrededor de un 2% (p = 0,02) de las muestras, frente a la exactitud del 99% que deparaban las técnicas de PCR. Los resultados obtenidos por una serie de laboratorios en 2008 ponían de manifiesto una evidente dificultad para distinguir entre T. asinigenitalis y T. equigenitalis, ya fuera por cultivo o por PCR, dificultad que resultaba menos obvia en 2016. También se observó que las tasas de detección en cultivo de T. equigenitalis obtenidas por laboratorios que también analizaban las muestras por PCR eran alrededor de un 4% superiores (p < 0,05) a las de laboratorios que empleaban únicamente el método de cultivo.

Pooling of genital swabs for detection by PCR of Taylorella equigenitalis, the cause of contagious equine metritis.

BACKGROUND: Sets of genital swabs are routinely taken from horses to screen for the presence of Taylorella equigenitalis, the cause of contagious equine metritis. Typically, two to four different sites are swabbed at a time and tested by culture or PCR. OBJECTIVES: This study explored the feasibility of pooling these swabs for a single PCR test per animal instead of testing each swab individually. STUDY DESIGN: In vitro. METHODS: PCR signal strengths (Ct values) from 149 historical PCR positive genital swabs, together with historical data on the number of swabs in a set expected to be positive, were used to assess the suitability of pooling for screening horses for T. equigenitalis infection in the population at large. Twenty-four sets of four equine genital swabs were tested. The sets were prepared in the laboratory using one or more swabs positive for T. equigenitalis from naturally infected cases. Positive and negative swabs were selected to reflect a typical range of PCR Ct values expected in field cases of T. equigenitalis infection. These pools were tested by an established PCR to assess the impact and suitability of a PCR test on pooled swabs compared to individual swab testing, by comparing the Ct values. RESULTS: Pooling one positive swab with three negative swabs produced a small drop in Ct value but all pools were still clearly positive. MAIN LIMITATIONS: Large numbers of field positive horses are not available, but the proof of concept approach with laboratory prepared pools shows the method is applicable to field cases. CONCLUSIONS: It was concluded that pooling of swabs would confer no appreciable drop in the ability to detect a positive animal compared to individual swab testing; pooling is therefore a suitable alternative to individual swab testing with reduced costs. The Summary is available in Spanish - see Supporting Information.

An in-vitro investigation into the efficacy of disinfectants used in the duck industry against Salmonella.

In 2010, 81 confirmed cases of Salmonella Typhimurium DT8 were reported across England and Northern Ireland - an increase of 26% from 2009 and 41% since 2008. Five cases were hospitalized and one death reported, with a strong association found between cases and the consumption of duck eggs. Once present on farms, Salmonella may become persistent and can survive for long periods of time in residual organic matter, increasing risk of infection for follow-on flocks if cleaning and disinfection is not carried out effectively. The aim of this study was to investigate the efficacy of a range of disinfectants used by the duck industry against Salmonella using laboratory models. Sixteen products were selected from seven chemical groups and the Minimum Inhibitory Concentration and Minimum Bactericidal Concentrations determined. Each product was also tested at the recommended general orders (GO) concentration using a faecal suspension model to mimic boot dips and a surface contamination model to simulate contaminated building fabric and equipment. In the faecal suspension model, all products were effective at 2 × GO concentration, and activity was more inconsistent at GO concentration. At 0.5 × GO concentration, iodine-based and quaternary-ammonium-compound-based products were significantly less effective than products within other chemical groups (P < 0.001). Glutaraldehyde-based products were significantly more effective than the other products in the surface contamination tests (P < 0.001). Chlorocresol-based products were found to be most effective for use in boot dips and aldehyde-based products for surface disinfection, although there was variability between products within a chemical group.

Contralateral ulnar neuropathy following total hip replacement and intraoperative positioning.

Peripheral neuropathy is a rare but important complication of total hip arthroplasty (THA) and has previously been reported in the ipsilateral arm and associated with inflammatory arthritis. The results of 7004 primary hip arthroplasties performed between January 1993 and February 2009 were retrospectively reviewed to identify patients who reported ulnar neuropathy symptoms, with ten patients identified at mean follow-up of 57 months (range = 3-195 months). Eight patients experienced unilateral ulnar nerve symptoms in the contralateral upper limb post-surgery, one patient experienced symptoms in the ipsilateral upper limb and one patient experienced symptoms in both upper limbs. The incidence of post-THA ulnar neuropathy was 0.14%. All patients had a pre-operative diagnosis of osteoarthritis and none had diabetes, a previous history of neuropathy or inflammatory arthritis. All operations were primary arthroplasties and were performed under the care of a single surgeon in a single centre. Two of the ten patients (20%) had a general anaesthetic. The pattern of symptoms reported, i.e. mainly unilateral affecting the contralateral side with variable resolution, contrasts with previous studies and suggests that intraoperative patient positioning may be an important factor influencing ulnar neuropathy following THA. Attention to support and positioning of the contralateral arm may help reduce the incidence of this complication.

Investigation of serology for diagnosis of outbreaks of botulism in cattle.

Serology has been used to diagnose retrospectively types C and D outbreaks of botulism in cattle in Australia and this study has investigated whether the approach would be applicable in England and Wales. Three hundred sera from routine surveillance submissions in England and Wales were used as a negative control population. Some stored sera were available from a small number of clinical cases of botulism and 125 samples were collected from cohort groups of clinical cases in four new outbreaks of botulism. Three of these outbreaks were identified as being caused by type D Clostridium botulinum toxin. Sera were tested by antibody ELISA in laboratories in Australia and Germany. There was no increase in the proportion of animals seropositive to type C or D antibody in the botulism-associated cattle. The proportion of samples which were seropositive to type D antibodies was <2% in both the negative control and outbreak populations. It was concluded that single time serology is unlikely to be helpful for retrospective diagnosis of outbreaks of type D botulism in England and Wales.

Atypical interstitial pneumonia in grazing adult red deer (Cervus elaphus).

A herd of red deer experienced a small outbreak of atypical interstitial pneumonia on two occasions 3 years apart. The first occasion involved the death of two of a group of 70 hinds and the second outbreak involved a single death in a similar sized group. On both occasions a number of the adults exhibited increased respiratory effort, particularly on exercise. Both outbreaks occurred in July, a few days after moving the herd from a close grazed grass paddock to an aftermath paddock, which had regrown to a good sward. The history and pathology is reminiscent of 3-methyl indole toxicity in cattle.

The improved specificity of bovine brucellosis testing in Great Britain.

The brucellosis surveillance scheme in Great Britain includes the serological testing of approximately 1 million bovine samples per year. These are screened by iELISA, positives going forward for confirmatory testing by CFT and SAT. Samples positive by confirmatory testing prompt substantial field investigations and interventions, but the animals involved are usually uninfected. Described below are a series of modifications to the screening method, which have resulted in a 10-fold reduction in false positive results whilst maintaining sensitivity. The key modifications include the introduction of blocking agents, a change in serum test dilution and the introduction of a control that directly defines the positive/negative cut-off. These simple modifications have had a large impact in reducing the cost of the surveillance programme due to reductions in confirmatory test requirements and a knock on effect of reducing costly field intervention.

Protection against bovine respiratory syncytial virus challenge following a single dose of vaccine in young calves with maternal antibody.

Twenty-one young calves with maternally derived antibody to bovine respiratory syncytial virus (BRSV) were divided into three groups of seven, each group balanced for BRSV antibody titre. The calves had no evidence of previous exposure to BRSV. The calves in one group were given a single dose of a monovalent modified live BRSV vaccine; the calves in the second group were given a single dose of an inactivated combined BRSV, parainfluenza virus type 3, Mannheimia haemolytica vaccine and the calves in the third group were left as unvaccinated controls. Three weeks after the single doses of vaccine, all the calves were challenged with BRSV. The clinical signs of disease were mild, and virus excretion was limited to two calves in the group given the inactivated vaccine, compared with six in the negative controls (P = 0.05) and five in the group given the live vaccine. The mean virus excretion titres after the challenge were not significantly different between the groups. There was little seroconversion before the challenge, but six of the seven calves in the group given the inactivated vaccine showed significant seroconversion within two weeks after the challenge, compared with only one calf in each of the other two groups (P = 0.015).

Treatment of canine pyoderma with ibafloxacin and marbofloxacin--fluoroquinolones with different pharmacokinetic profiles.

Dogs with superficial or deep pyoderma (n = 228) presented to first opinion veterinarians (n = 20) were treated orally with either ibafloxacin, at a dosage of 15 mg/kg, or marbofloxacin, at a dosage of 2 mg/kg, once daily for 3-16 weeks. On initial presentation, 35% of the cases were classified as having recurrent pyoderma and 40% as having deep pyoderma. Staphylococci (mainly Staphylococcus intermedius) were isolated from over 90% of the cases. The average treatment periods were 41 +/- 26 and 38 +/- 21 days in the ibafloxacin and marbofloxacin groups, respectively. One week after the cessation of treatment, 74 and 81% of dogs (P > 0.05) in the ibafloxacin and marbofloxacin groups, respectively, were classified as having responded to treatment. One month after the cessation of treatment, 70% of the dogs in each group were still classified as cured or improved, and 3 and 11% (P < 0.05) in the ibafloxacin and marbofloxacin groups, respectively, were classified as having relapsed. Despite having different pharmacokinetic profiles, ibafloxacin and marbofloxacin produced similar results when used under field conditions at the recommended dosages.

Field trial of a planned breeding regimen for dairy cows, using gonadotrophin-releasing hormone and prostagladin F2alpha.

A planned breeding regimen, using gondadotrophin-releasing hormone (GnRH), prostaglandin F2alpha, and a second dose of GnRH, followed by a fixed time insemination, was evaluated in comparison with a negative control on eight commercial dairy farms in the south of England. Fertility data were collected from the 220 cows in the planned breeding group and from 220 matched control cows inseminated at observed oestrus. The planned regimen induced visible oestrus in the vast majority of the cows, and serving the cows at this oestrus reduced the calving to conception interval by 15 days, resulting in 12 per cent more cows being pregnant by 125 days after calving, and 6 per cent more by 150 days. The results from the individual farms suggested that more benefit may be derived from using the regimen in herds with only average fertility indices. There was also evidence to suggest that the second GnRH injection was important, even in cows that came on heat and were served before the fixed time insemination.

Development of a gonadotrophin-releasing hormone and prostaglandin regimen for the planned breeding of dairy cows.

Four studies were carried out to determine the ovarian responses of dairy cows undergoing natural oestrous cycles to sequential injections of gonadotrophin-releasing hormone (GnRH), followed seven days later by prostaglandin and, 48 to 72 hours later, by a second injection of GnRH. In study 1, of 60 cows so treated, 47 were in the intended periovulatory phase when a fixed-time insemination was given 72 hours after the prostaglandin. In study 2, detailed observations were made in 32 cows treated as in study 1, using ultrasound to determine the optimum time to administer the second dose of GnRH. Ovulation was most effectively synchronised by giving GnRH 56 to 60 hours after the prostaglandin. Study 3 investigated the timing of ovulation when no initial dose of GnRH was given. Six cows were injected with prostaglandin on day 12 of the oestrous cycle, followed by GnRH 60 hours later. Five of the six cows ovulated 24 to 36 hours after GnRH, an equivalent timing and synchrony to that in study 2, in which a dose of GnRH had been given seven days before prostaglandin. In study 4, an initial dose of GnRH was given to six cows late (day 17) in the oestrous cycle, and prostaglandin seven days later. The GnRH treatment delayed luteolysis in five of the cows so that they were responsive to the prostaglandin and ovulated 24 to 36 hours after the second dose of GnRH. The use of GnRH (day 0) - prostaglandin (day 7) - GnRH (day 9.5) appears to be an effective means of synchronising ovulation in most cows.