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1.  Prevalence of tick-borne encephalitis virus antibodies in dogs from Denmark 
Background
Large regions of central and eastern Europe are recognized as areas where tick-borne encephalitis virus (TBEV) is endemic, including countries neighbouring Denmark. It is therefore timely and relevant to determine if TBEV infections occur in Denmark. This study investigates the presence of antibodies against TBEV in a cross-section of the Danish canine population to assess the level of exposure to TBEV and possibly identify TBEV microfoci in Denmark.
Methods
Blood samples were collected from 125 dogs originating from five regions of Denmark between November 2005 and March 2006. Serum was tested by indirect ELISA. All positive and borderline samples were re-evaluated by neutralisation test (NT).
Results
The prevalence of TBEV serocomplex antibodies was 30% by ELISA and 4.8% by NT (with 100%-neutralising capacity). The island of Bornholm was the only area in Denmark with NT positive samples.
Conclusions
The island of Bornholm is an area with a high risk of encountering TBEV microfoci. The presence of TBEV serocomplex antibodies in many sentinel animals from other parts of Denmark points toward existence of other TBEV microfoci. Discrepancies found between ELISA and NT results stress the importance of careful evaluation of serological tests, when interpreting results.
doi:10.1186/1751-0147-51-56
PMCID: PMC2807863  PMID: 20040077
2.  Anaplasma phagocytophilum in Danish sheep: confirmation by DNA sequencing 
Background
The presence of Anaplasma phagocytophilum, an Ixodes ricinus transmitted bacterium, was investigated in two flocks of Danish grazing lambs. Direct PCR detection was performed on DNA extracted from blood and serum with subsequent confirmation by DNA sequencing.
Methods
31 samples obtained from clinically normal lambs in 2000 from Fussingø, Jutland and 12 samples from ten lambs and two ewes from a clinical outbreak at Feddet, Zealand in 2006 were included in the study. Some of the animals from Feddet had shown clinical signs of polyarthritis and general unthriftiness prior to sampling. DNA extraction was optimized from blood and serum and detection achieved by a 16S rRNA targeted PCR with verification of the product by DNA sequencing.
Results
Five DNA extracts were found positive by PCR, including two samples from 2000 and three from 2006. For both series of samples the product was verified as A. phagocytophilum by DNA sequencing.
Conclusions
A. phagocytophilum was detected by molecular methods for the first time in Danish grazing lambs during the two seasons investigated (2000 and 2006).
doi:10.1186/1751-0147-51-55
PMCID: PMC2806374  PMID: 20025738
3.  Oral malignant melanomas and other head and neck neoplasms in Danish dogs - data from the Danish Veterinary Cancer Registry 
Background
Head and neck cancers (HNC) are relatively common and often very serious diseases in both dogs and humans. Neoplasms originating in the head and neck region are a heterogeneous group. HNC often has an unfavourable prognosis and the proximity of the tissue structures renders extirpation of tumours with sufficient margins almost incompatible with preservation of functionality. In humans oral malignant melanoma (OMM) is extremely rare, but represents a particular challenge since it is highly aggressive as is the canine counterpart, which thus may be of interest as a spontaneous animal model.
Methods
Canine cases entered in the Danish Veterinary Cancer Registry (DVCR) from May 15th 2005 through February 29th 2008 were included in this study. Fisher's exact test was used to compare proportions of HNC in dogs and humans as well as proportions of surgically treated cases of OMM and squamous cell carcinomas (SCC). Also the proportions of benign and malignant neoplasms of different locations in dogs were compared using Fisher's exact test.
Results
A total of 1768 cases of neoplasias (679 malignant, 826 benign, 263 unknown) were submitted. Of all neoplasias HNC accounted for 7.2% (n = 128). Of these, 64 (50%) were malignant and 44 (34%) benign. The most common types of malignant neoplasia were SCC (18; 28% of malignant), OMM (13; 20% of malignant), soft tissue sarcoma (11; 17% of malignant) and adenocarcinoma (5; 11% of malignant). The most common types of benign neoplasms were adenoma (7; 16% of benign), polyps (6; 14% of benign) and fibroma (5; 11% of benign).
Conclusions
In the current study, the proportion of neoplasia in the head and neck region in dogs in Denmark was similar to other canine studies and significantly more common than in humans with a large proportion of malignancies. Spontaneous HNC in dogs thus, may serve as a model for HNC in humans.
Canine OMM is a spontaneous cancer in an outbred, immune-competent large mammal population and could be a clinical model for OMM in humans.
doi:10.1186/1751-0147-51-54
PMCID: PMC2803174  PMID: 20021647
4.  Assessment of sperm quality traits in relation to fertility in boar semen 
Background
Several studies have been published where sperm plasma membrane integrity correlated to fertility. In this study we describe a simple fluorometer-based assay where we monitored the fluorescence intensity of artificially membrane-ruptured spermatozoa with a fixed time staining with fluorescent DNA dyes.
Methods
Membrane-impermeant fluorescent dyes Hoechst 33258 (H258) and propidium iodide (PI) were used to measure the fluorescence of the nucleus in artificially membrane ruptured spermatozoa and membrane-permeant dye Hoechst 33342 (H342) was used to measure fluorescence of intact spermatozoa. The concentration of spermatozoa in insemination doses varied from 31.2 × 106/ml to 50 × 106/ml and the average value was 35 × 106/ml. Each boar was represented by three consecutive ejaculates, collected at weekly intervals. Nonreturn rate within 60 days of first insemination (NR %) and litter size (total number of piglets born) of multiparous farrowings were used as fertility measures.
Results
Sperm fluorescence intensity of H258 and H342, but not the fluorescence intensity of PI-stained spermatozoa correlated significantly with the litter size of multiparous farrowings, values being r = - 0.68 (P < 0.01) for H258, r = - 0.69 (P < 0.01) for H342 and r = - 0.38, (P = 0.11) for PI.
Conclusions
The increase in fluorescence values of membrane-ruptured H258 and unruptured H342-stained spermatozoa in boar AI doses can be associated with smaller litter size after AI. This finding indicates that the fluorescence properties of the sperm nucleus could be used to select for AI doses with greater fertilizing potential.
doi:10.1186/1751-0147-51-53
PMCID: PMC2801498  PMID: 20015377
5.  Effects of dietary supplementation of nickel and nickel-zinc on femoral bone structure in rabbits 
Background
Nickel (Ni) and zinc (Zn) are trace elements present at low concentrations in agroecosystems. Nickel, however, may have toxic effects on living organisms and is often considered as a contaminant. This study reports the effect of peroral administrated Ni or a combination of Ni and Zn on femoral bone structure in rabbits.
Methods
One month-old female rabbits were divided into three groups of five animals each. Group 1 rabbits were fed a granular feed mixture with addition of 35 g NiCl2 per 100 kg of mixture for 90 days. In group 2, animals were fed a mixture containing 35 g NiCl2 and 30 g ZnCl2 per 100 kg of mixture. Group 3 without administration of additional Ni or Zn served as control. After the 90-day experimental period, femoral length, femoral weight and histological structure of the femur were analyzed and compared.
Results
The results did not indicate a statistically significant difference in either femoral length or weight between the two experimental groups and the control group. Also, differences in qualitative histological characteristics of the femora among rabbits from the three groups were absent, except for a fewer number of secondary osteons found in the animals of groups 1 and 2. However, values for vascular canal parameters of primary osteons were significantly lower in group 1 than in the control one. Peroral administration of a combination of Ni and Zn (group 2) led to a significant decreased size of the secondary osteons.
Conclusions
The study indicates that dietary supplementation of Ni (35 g NiCl2 per 100 kg of feed mixture) and Ni-Zn combination (35 g NiCl2 and 30 g ZnCl2 per 100 kg of the mixture) affects the microstructure of compact bone tissue in young rabbits.
doi:10.1186/1751-0147-51-52
PMCID: PMC2801497  PMID: 20003522
6.  Validation of computerized diagnostic information in a clinical database from a national equine clinic network 
Background
Computerized diagnostic information offers potential for epidemiological research; however data accuracy must be addressed. The principal aim of this study was to evaluate the completeness and correctness of diagnostic information in a computerized equine clinical database compared to corresponding hand written veterinary clinical records, used as gold standard, and to assess factors related to correctness. Further, the aim was to investigate completeness (epidemiologic sensitivity), correctness (positive predictive value), specificity and prevalence for diagnoses for four body systems and correctness for affected limb information for four joint diseases.
Methods
A random sample of 450 visits over the year 2002 (nvisits = 49,591) was taken from 18 nation wide clinics headed under one company. Computerized information for the visits selected and copies of the corresponding veterinary clinical records were retrieved. Completeness and correctness were determined using semi-subjective criteria. Logistic regression was used to examine factors associated with correctness for diagnosis.
Results
Three hundred and ninety six visits had veterinary clinical notes that were retrievable. The overall completeness and correctness were 91% and 92%, respectively; both values considered high. Descriptive analyses showed significantly higher degree of correctness for first visits compared to follow up visits and for cases with a diagnostic code recorded in the veterinary records compared to those with no code noted. The correctness was similar regardless of usage category (leisure/sport horse, racing trotter and racing thoroughbred) or gender.
For the four body systems selected (joints, skin and hooves, respiratory, skeletal) the completeness varied between 71% (respiration) and 91% (joints) and the correctness ranged from 87% (skin and hooves) to 96% (respiration), whereas the specificity was >95% for all systems. Logistic regression showed that correctness was associated with type of visit, whether an explicit diagnostic code was present in the veterinary clinical record, and body system. Correctness for information on affected limb was 95% and varied with joint.
Conclusion
Based on the overall high level of correctness and completeness the database was considered useful for research purposes. For the body systems investigated the highest level of completeness and correctness was seen for joints and respiration, respectively.
doi:10.1186/1751-0147-51-50
PMCID: PMC2801496  PMID: 20003256
7.  Effects of dietary phytoestrogens on plasma testosterone and triiodothyronine (T3) levels in male goat kids 
Background
Exposure to xenoestrogens in humans and animals has gained increasing attention due to the effects of these compounds on reproduction. The present study was undertaken to investigate the influence of low-dose dietary phytoestrogen exposure, i.e. a mixture of genistein, daidzein, biochanin A and formononetin, on the establishment of testosterone production during puberty in male goat kids.
Methods
Goat kids at the age of 3 months received either a standard diet or a diet supplemented with phytoestrogens (3 - 4 mg/kg/day) for ~3 months. Plasma testosterone and total and free triiodothyronine (T3) concentrations were determined weekly. Testicular levels of testosterone and cAMP were measured at the end of the experiment. Repeated measurement analysis of variance using the MIXED procedure on the generated averages, according to the Statistical Analysis System program package (Release 6.12, 1996, SAS Institute Inc., Cary, NC, USA) was carried out.
Results
No significant difference in plasma testosterone concentration between the groups was detected during the first 7 weeks. However, at the age of 5 months (i.e. October 1, week 8) phytoestrogen-treated animals showed significantly higher testosterone concentrations than control animals (37.5 nmol/l vs 19.1 nmol/l). This elevation was preceded by a rise in plasma total T3 that occurred on September 17 (week 6). A slightly higher concentration of free T3 was detected in the phytoestrogen group at the same time point, but it was not until October 8 and 15 (week 9 and 10) that a significant difference was found between the groups. At the termination of the experiment, testicular cAMP levels were significantly lower in goats fed a phytoestrogen-supplemented diet. Phytoestrogen-fed animals also had lower plasma and testicular testosterone concentrations, but these differences were not statistically significant.
Conclusion
Our findings suggest that phytoestrogens can stimulate testosterone synthesis during puberty in male goats by increasing the secretion of T3; a hormone known to stimulate Leydig cell steroidogenesis. It is possible that feedback signalling underlies the tendency towards decreased steroid production at the end of the experiment.
doi:10.1186/1751-0147-51-51
PMCID: PMC2803173  PMID: 20003293
8.  Environmental contamination by vancomycin resistant enterococci (VRE) in Swedish broiler production 
Background
Vancomycin resistant enterococci are a frequent cause of nosocomial infections and their presence among farm animals is unwanted. Using media supplemented with vancomycin an increase in the proportion of samples from Swedish broilers positive for vancomycin resistant enterococci has been detected. The situation at farm level is largely unknown. The aims of this study were to obtain baseline knowledge about environmental contamination with vancomycin resistant enterococci in Swedish broiler production and the association between environmental contamination and colonisation of birds.
Methods
Environmental samples were taken before, during and after a batch of broilers at three farms. Samples were cultured both qualitatively and semi-quantitatively for vancomycin resistant enterococci. In addition, caecal content from birds in the batch following at each farm was cultured qualitatively for vancomycin resistant enterococci.
Results
The number of samples positive for vancomycin resistant enterococci varied among the farms. Also the amount of vancomycin resistant enterococci in the positive samples and the proportion of caecal samples containing vancomycin resistant enterococci varied among the farms. Still, the temporal changes in environmental contamination followed a similar pattern in all farms.
Conclusion
Vancomycin resistant enterococci persist in the compartments even after cleaning and the temporal changes in environmental contamination were similar among farms. There were however differences among farms regarding both degree of contamination and proportion of birds colonized with vancomycin resistant enterococci. The proportion of colonized birds and the amount of vancomycin resistant enterococci in the compartments seems to be associated. If the factor(s) causing the differences among farms could be identified, it might be possible to reduce both the risk for colonisation by vancomycin resistant enterococci of the subsequent flock and the risk for spread of vancomycin resistant enterococci via the food chain to humans.
doi:10.1186/1751-0147-51-49
PMCID: PMC2794861  PMID: 19954525
9.  Fixed-time artificial insemination in beef cattle 
Background
The study was designed to test the effect of fixed-time artificial insemination (fixed-AI) after the slightly modified Ovsynch protocol on the pregnancy rate in beef cattle in Finnish field conditions. The modification was aimed to optimize the number of offsprings per AI dose.
Methods
Ninety Charolais cows and heifers were entered into the program an average of 1.8 times. Thus, 164 animal cases were included. Animals were administered 10-12 μg of buserelin. Seven days later animals without a corpus luteum (CL) were rejected (20.7%) while the remaining 130 cases with a CL were administered prostaglandin F2α, followed 48 h later with a second injection of buserelin (8-10 μg). Fixed-AI was performed 16-20 hours after the last injection.
Results
The pregnancy rate was 51.5% (67/130). The pregnancy rate after a short interval (50-70 d) from calving to entering the program was significantly higher than that after a long interval (>70 d).
Conclusion
This protocol seems to give acceptable pregnancy results in beef herds and its effect on saving labour is notable.
doi:10.1186/1751-0147-51-48
PMCID: PMC2790447  PMID: 19948052
10.  Prevalence of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in questing Ixodes ricinus ticks in relation to the density of wild cervids 
Background
Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum have been considered as pathogens in animals and humans. The role of wild cervids in the epidemiology is not clear. We analyzed questing Ixodes ricinus ticks collected in spring for these pathogens from sites with high (Fjelløyvær and Strøm) and low density (Tjore, Hinnebu and Jomfruland) of wild cervids to study the spread of the pathogens in questing ticks.
Methods
For detection of Anaplasma phagocytophilum a 77-bp fragment in the msp2 gene was used. Detection of Borrelia burgdorferi sensu lato was performed using the FL6 and FL7 primers according to sequences of conserved regions of the fla gene. The OspA gene located on the linear 49-kb plasmid was used as target in multiplex PCR for genotyping. Genospecies-specific primers were used in the PCR for Borrelia burgdorferi sensu stricto, B. afzelii and B. garinii.
Results
Infection rates with Borrelia spp. were significantly lower at Fjelløyvær and Strøm compared to Tjore and Hinnebu; Fjelløyvær vs. Tjore (χ2 = 20.27, p < 0.0001); Fjelløyvær vs. Hinnebu (χ2 = 24.04, p < 0.0001); Strøm vs. Tjore (χ2 = 11.47, p = 0.0007) and Strøm vs. Hinnebu (χ2 = 16.63, p < 0.0001). The Borrelia genospecies were dominated by. B. afzelii (82%) followed by B. garinii (9.7%) and B. burgdorferi sensu stricto (6.9%). B. burgdorferi s.s. was only found on the island of Jomfruland. The infection rate of Anaplasma phagocytophilum showed the following figures; Fjelløyvær vs Hinnebu (χ2 = 16.27, p = 0.0001); Strøm vs. Tjore (χ2 = 13.16, p = 0.0003); Strøm vs. Hinnebu (χ2 = 34.71, p < 0.0001); Fjelløyvær vs. Tjore (χ2 = 3.19, p = 0.0742) and Fjelløyvær vs. Støm (χ2 = 5.06, p = 0.0245). Wild cervids may serve as a reservoir for A. phagocytophilum. Jomfruland, with no wild cervids but high levels of migrating birds and rodents, harboured both B. burgdorferi s.l. and A. phagocytophilum in questing I. ricinus ticks. Birds and rodents may play an important role in maintaining the pathogens on Jomfruland.
Conclusion
The high abundance of roe deer and red deer on the Norwegian islands of Fjelløyvær and Strøm may reduce the infection rate of Borrelia burgdorferi sensu lato in host seeking Ixodes ricinus, in contrast to mainland sites at Hinnebu and Tjore with moderate abundance of wild cervids. The infection rate of Anaplasma phagocytophilum showed the opposite result with a high prevalence in questing ticks in localities with a high density of wild cervids compared to localities with lower density.
doi:10.1186/1751-0147-51-47
PMCID: PMC2788566  PMID: 19943915
11.  Isolation and molecular characterization of multidrug-resistant Gram-negative bacteria from imported flamingos in Japan 
Imported animals, especially those from developing countries, may constitute a potential hazard to native animals and to public health. In this study, a new flock of lesser flamingos imported from Tanzania to Hiroshima Zoological Park were screened for multidrug-resistant Gram-negative bacteria, integrons and antimicrobial resistance genes. Thirty-seven Gram-negative bacterial isolates were obtained from the flamingos. Seven isolates (18.9%) showed multidrug resistance phenotypes, the most common being against: ampicillin, streptomycin, tetracycline, trimethoprim/sulfamethoxazole and nalidixic acid. Molecular analyses identified class 1 and class 2 integrons, β-lactamase-encoding genes, blaTEM-1 and blaCTX-M-2 and the plasmid-mediated quinolone resistance genes, qnrS and qnrB. This study highlights the role of animal importation in the dissemination of multidrug-resistant bacteria, integrons and antimicrobial resistance genes from one country to another.
doi:10.1186/1751-0147-51-46
PMCID: PMC2794275  PMID: 19930691
12.  Anthelmintic efficacy on Parascaris equorum in foals on Swedish studs 
Background
In the last few years stud farms have experienced increasing problems with Parascaris equorum infections in foals despite intensive deworming programs. This has led to the question as to whether the anthelmintic drugs used against this parasite are failing. This study aimed to investigate the efficacy of ivermectin, fenbendazole and pyrantel on the faecal output of ascarid eggs of foals.
Methods
A Faecal Egg Count Reduction Test (FECRT) was performed on nine large studs in Sweden. Anthelmintic drugs were given orally and faecal samples were examined for ascarid eggs on the day of deworming and 14 days later. Faecal Egg Count Reductions (FECRs) were calculated on arithmetic means of transformed individual FECRs and on arithmetic means of individual FECRs.
Results
Seventy-nine (48%) out of a total of 165 foals sampled were positive for P. equorum eggs before deworming and 66 of these met the criteria for being used in the efficacy assessment. It was shown that there was no, or very low activity of ivermectin on the output of ascarid eggs in the majority of the foals, whereas for fenbendazole and pyrantel it was >90%.
Conclusion
Ivermectin resistance was shown in 5 out of 6 farms. Therefore, ivermectin should not be the drug of choice in the control of P. equorum infections in foals. According to the results of this study, fenbendazole or pyrantel are still effective and should be used against this parasite.
doi:10.1186/1751-0147-51-45
PMCID: PMC2788565  PMID: 19930608
13.  Maximum lying bout duration affects the occurrence of shoulder lesions in sows 
Shoulder lesions are caused by tissue breakdown of the skin and/or underlying tissue as a result of long lasting pressure. The lesions are commonly seen in sows during the period of lactation and contribute to poor animal welfare as well as affecting the consumers' attitudes towards the swine industry. The aim of this study was to investigate the correlation between prolonged recumbency during early lactation and development of shoulder lesions, in particular the lying bout time. Eighteen sows of Swedish Landrace were observed for 24 hours during the day of farrowing and day 2, 4, 9 and 11 after farrowing in May 2009. The data were analysed for correlations between the duration of the longest observed uninterrupted lying bout and the prevalence of shoulder lesions recorded at weaning (week 5).
In the study, shoulder lesions were observed in eight of the eighteen sows at the time of weaning. The total lying time of the sows was highest on day 0 and day 2, when the proportion of time spent in lateral recumbency over the 24-hour period was on average 80 percent. The longest lying bout had an average duration of 6,3 hours (right side) and 7,2 hours (left side). A significant correlation (Spearman rank coefficient = 0,88; P < 0,05) was found between the duration of the longest observed uninterrupted lying bout and the occurrence of shoulder lesions on right side among well conditioned sows with a low amount of straw present at farrowing. This suggests that avoiding prolonged uninterrupted recumbency contributes to the prevention of shoulder lesions in sows.
doi:10.1186/1751-0147-51-44
PMCID: PMC2785815  PMID: 19930541
14.  Experimental infection in calves with a specific subtype of verocytotoxin-producing Escherichia coli O157:H7 of bovine origin 
Background
In Sweden, a particular subtype of verocytotoxin-producing Escherichia coli (VTEC) O157:H7, originally defined as being of phage type 4, and carrying two vtx2 genes, has been found to cause the majority of reported human infections during the past 15 years, including both sporadic cases and outbreaks. One plausible explanation for this could be that this particular subtype is better adapted to colonise cattle, and thereby may be excreted in greater concentrations and for longer periods than other VTEC O157:H7 subtypes.
Methods
In an experimental study, 4 calves were inoculated with 109 colony forming units (cfu) of strain CCUG 53931, representative of the subtype VTEC O157:H7 (PT4;vtx2;vtx2c). Two un-inoculated calves were co-housed with the inoculated calves. Initially, the VTEC O157:H7 strain had been isolated from a dairy herd with naturally occurring infection and the farm had previously also been linked to human infection with the same strain. Faecal samples were collected over up to a 2-month period and analysed for VTEC O157 by immuno-magnetic separation (IMS), and IMS positive samples were further analysed by direct plating to elucidate the shedding pattern. Samples were also collected from the pharynx.
Results
All inoculated calves proved culture-positive in faeces within 24 hours after inoculation and the un-inoculated calves similarly on days 1 and 3 post-inoculation. One calf was persistently culture-positive for 43 days; in the remainder, the VTEC O157:H7 count in faeces decreased over the first 2 weeks. All pharyngeal samples were culture-negative for VTEC O157:H7.
Conclusion
This study contributes with information concerning the dynamics of a specific subtype of VTEC O157:H7 colonisation in dairy calves. This subtype, VTEC O157:H7 (PT4;vtx2;vtx2c), is frequently isolated from Swedish cattle and has also been found to cause the majority of reported human infections in Sweden during the past 15 years. In most calves, inoculated with a representative strain of this specific subtype, the numbers of shed bacteria declined over the first two weeks. One calf could possibly be classified as a high-shedder, excreting high levels of the bacterium for a prolonged period.
doi:10.1186/1751-0147-51-43
PMCID: PMC2776595  PMID: 19878595
15.  Insurance data for research in companion animals: benefits and limitations 
The primary aim of this article is to review the use of animal health insurance data in the scientific literature, especially in regard to morbidity or mortality in companion animals and horses. Methods and results were compared among studies on similar health conditions from different nations and years. A further objective was to critically evaluate benefits and limitations of such databases, to suggest ways to maximize their utility and to discuss the future use of animal insurance data for research purposes. Examples of studies on morbidity, mortality and survival estimates in dogs and horses, as well as neoplasia in dogs, are discussed.
We conclude that insurance data can and should be used for research purposes in companion animals and horses. Insurance data have been successfully used, e.g. to quantify certain features that may have been hitherto assumed, but unmeasured. Validation of insurance databases is necessary if they are to be used in research. This must include the description of the insured population and an evaluation of the extent to which it represents the source population. Data content and accuracy must be determined over time, including the accuracy/consistency of diagnostic information. Readers must be cautioned as to limitations of the databases and, as always, critically appraise findings and synthesize information with other research. Similar findings from different study designs provide stronger evidence than a sole report. Insurance data can highlight common, expensive and severe conditions that may not be evident from teaching hospital case loads but may be significant burdens on the health of a population.
doi:10.1186/1751-0147-51-42
PMCID: PMC2777155  PMID: 19874612
16.  Superinfection occurs in Anaplasma phagocytophilum infected sheep irrespective of infection phase and protection status 
Background
Anaplasma phagocytophilum infection in domestic ruminants is widespread in the coastal areas of southern Norway. The bacteria may persist in mammalian hosts. Several genetic variants of A. phagocytophilum exist. In the present study, we investigate whether superinfection occurs in the acute and persistent phase of the infection.
Methods
Five-month-old lambs of the Norwegian Dala breed were experimentally infected with two 16S rRNA gene variants of A. phagocytophilum, i.e. A. phagocytophilum variant 1 (GenBank accession number M73220) and variant 2 (GenBank acc. no. AF336220). Eighteen lambs were used, two lambs in each group. Eight groups were experimentally inoculated with either variant 1 or 2 on day 0. Six of these groups were then challenged with the other variant on either days 7, 42 or 84, respectively. One group was left uninfected. The occurrence of A. phagocytophilum in blood samples was determined using semi-nested PCR analysis and gene sequencing. Specific antibodies were measured by an indirect immunofluorescence antibody assay (IFA).
Results
A. phagocytophilum variant 1 and 2 differed significantly with regards to clinical reaction and cross-immunity in infected lambs. Both variants were found in the blood after challenge. However, variant 1 was detected most frequently.
Conclusion
The present experiment indicates that superinfection of different genotypes occurs during the acute as well as the persistent phase of an A. phagocytophilum infection, even in lambs protected against the challenged infection.
doi:10.1186/1751-0147-51-41
PMCID: PMC2772837  PMID: 19857248
17.  Demodex gatoi -associated contagious pruritic dermatosis in cats - a report from six households in Finland 
Background
Demodex gatoi is unique among demodectic mites. It possesses a distinct stubby appearance, and, instead of residing in the hair follicles, it dwells in the keratin layer of the epidermis, causing a pruritic and contagious skin disease in cats. Little is known of the occurrence of D. gatoi in Europe or control of D. gatoi infestation.
Case presentation
We describe D. gatoi in 10 cats, including five Cornish Rex, two Burmese, one Exotic, one Persian and one Siamese, living in six multi-cat households in different locations in Finland containing 21 cats in total. Intense pruritus was the main clinical sign. Scaling, broken hairs, alopecia and self-inflicted excoriations were also observed.
Diagnosis was based on finding typical short-bodied demodectic mites in skin scrapings, skin biopsies or on tape strips. Other pruritic skin diseases, such as allergies and dermatophytoses, were ruled out. In one household, despite finding several mites on one cat, all six cats of the household remained symptomless.
Amitraz used weekly at a concentration of 125-250 ppm for 2-3 months, proved successful in three households, 2% lime sulphur weekly dips applied for six weeks in one household and peroral ivermectin (1 mg every other day for 10 weeks) in one household. Previous trials in four households with imidacloprid-moxidectin, selamectin or injected ivermectin given once or twice a month appeared ineffective.
Conclusion
D. gatoi-associated dermatitis is an emerging contagious skin disease in cats in Finland. Although pruritus is common, some cats may harbour the mites without clinical signs. In addition, due to translucency of the mites and fastidious feline grooming habits, the diagnosis may be challenging. An effective and convenient way to treat D. gatoi infestations has yet to emerge.
doi:10.1186/1751-0147-51-40
PMCID: PMC2770525  PMID: 19843334
18.  Ruminal acidosis and the rapid onset of ruminal parakeratosis in a mature dairy cow: a case report 
A mature dairy cow was transitioned from a high forage (100% forage) to a high-grain (79% grain) diet over seven days. Continuous ruminal pH recordings were utilized to diagnose the severity of ruminal acidosis. Additionally, blood and rumen papillae biopsies were collected to describe the structural and functional adaptations of the rumen epithelium. On the final day of the grain challenge, the daily mean ruminal pH was 5.41 ± 0.09 with a minimum of 4.89 and a maximum of 6.31. Ruminal pH was under 5.0 for 130 minutes (2.17 hours) which is characterized as the acute form of ruminal acidosis in cattle. The grain challenge increased blood beta-hydroxybutyrate by 1.8 times and rumen papillae mRNA expression of 3-hydroxy-3-methylglutaryl-coenzyme A synthase by 1.6 times. Ultrastructural and histological adaptations of the rumen epithelium were imaged by scanning electron and light microscopy. Rumen papillae from the high grain diet displayed extensive sloughing of the stratum corneum and compromised cell adhesion as large gaps were apparent between cells throughout the strata. This case report represents a rare documentation of how the rumen epithelium alters its function and structure during the initial stage of acute acidosis.
doi:10.1186/1751-0147-51-39
PMCID: PMC2770524  PMID: 19840395
19.  Propagation of Asian isolates of canine distemper virus (CDV) in hamster cell lines 
Backgrounds
The aim of this study was to confirm the propagation of various canine distemper viruses (CDV) in hamster cell lines of HmLu and BHK, since only a little is known about the possibility of propagation of CDV in rodent cells irrespective of their epidemiological importance.
Methods
The growth of CDV in hamster cell lines was monitored by titration using Vero.dogSLAMtag (Vero-DST) cells that had been proven to be susceptible to almost all field isolates of CDV, with the preparations of cell-free and cell-associated virus from the cultures infected with recent Asian isolates of CDV (13 strains) and by observing the development of cytopathic effect (CPE) in infected cultures of hamster cell lines.
Results
Eleven of 13 strains grew in HmLu cells, and 12 of 13 strains grew in BHK cells with apparent CPE of cell fusion in the late stage of infection. Two strains and a strain of Asia 1 group could not grow in HmLu cells and BHK cells, respectively.
Conclusion
The present study demonstrates at the first time that hamster cell lines can propagate the majority of Asian field isolates of CDV. The usage of two hamster cell lines suggested to be useful to characterize the field isolates biologically.
doi:10.1186/1751-0147-51-38
PMCID: PMC2774306  PMID: 19835588
20.  Spatial and temporal investigations of reported movements, births and deaths of cattle and pigs in Sweden 
Background
Livestock movements can affect the spread and control of contagious diseases and new data recording systems enable analysis of these movements. The results can be used for contingency planning, modelling of disease spread and design of disease control programs.
Methods
Data on the Swedish cattle and pig populations during the period July 2005 until June 2006 were obtained from databases held by the Swedish Board of Agriculture. Movements of cattle and pigs were investigated from geographical and temporal perspectives, births and deaths of cattle were investigated from a temporal perspective and the geographical distribution of holdings was also investigated.
Results
Most movements of cattle and pigs were to holdings within 100 km, but movements up to 1200 km occurred. Consequently, the majority of movements occurred within the same county or to adjacent counties. Approximately 54% of the cattle holdings and 45% of the pig holdings did not purchase any live animals. Seasonal variations in births and deaths of cattle were identified, with peaks in spring. Cattle movements peaked in spring and autumn. The maximum number of holdings within a 3 km radius of one holding was 45 for cattle and 23 for pigs, with large variations among counties. Missing data and reporting bias (digit preference) were detected in the data.
Conclusion
The databases are valuable tools in contact tracing. However since movements can be reported up to a week after the event and some data are missing they cannot replace other methods in the acute phase of an outbreak. We identified long distance transports of cattle and pigs, and these findings support an implementation of a total standstill in the country in the case of an outbreak of foot-and-mouth disease. The databases contain valuable information and improvements in data quality would make them even more useful.
doi:10.1186/1751-0147-51-37
PMCID: PMC2764703  PMID: 19811628
21.  Veterinary decision making in relation to metritis - a qualitative approach to understand the background for variation and bias in veterinary medical records 
Background
Results of analyses based on veterinary records of animal disease may be prone to variation and bias, because data collection for these registers relies on different observers in different settings as well as different treatment criteria. Understanding the human influence on data collection and the decisions related to this process may help veterinary and agricultural scientists motivate observers (veterinarians and farmers) to work more systematically, which may improve data quality. This study investigates qualitative relations between two types of records: 1) 'diagnostic data' as recordings of metritis scores and 2) 'intervention data' as recordings of medical treatment for metritis and the potential influence on quality of the data.
Methods
The study is based on observations in veterinary dairy practice combined with semi-structured research interviews of veterinarians working within a herd health concept where metritis diagnosis was described in detail. The observations and interviews were analysed by qualitative research methods to describe differences in the veterinarians' perceptions of metritis diagnosis (scores) and their own decisions related to diagnosis, treatment, and recording.
Results
The analysis demonstrates how data quality can be affected during the diagnostic procedures, as interaction occurs between diagnostics and decisions about medical treatments. Important findings were when scores lacked consistency within and between observers (variation) and when scores were adjusted to the treatment decision already made by the veterinarian (bias). The study further demonstrates that veterinarians made their decisions at 3 different levels of focus (cow, farm, population). Data quality was influenced by the veterinarians' perceptions of collection procedures, decision making and their different motivations to collect data systematically.
Conclusion
Both variation and bias were introduced into the data because of veterinarians' different perceptions of and motivations for decision making. Acknowledgement of these findings by researchers, educational institutions and veterinarians in practice may stimulate an effort to improve the quality of field data, as well as raise awareness about the importance of including knowledge about human perceptions when interpreting studies based on field data. Both recognitions may increase the usefulness of both within-herd and between-herd epidemiological analyses.
doi:10.1186/1751-0147-51-36
PMCID: PMC2745412  PMID: 19715614
22.  National surveillance of Salmonella enterica in food-producing animals in Japan 
A total of 518 fecal samples collected from 183 apparently healthy cattle, 180 pigs and 155 broilers throughout Japan in 1999 were examined to determine the prevalence and antimicrobial susceptibility of Salmonella. The isolation rates were 36.1% in broilers, 2.8% in pigs and 0.5% in cattle. S. enterica Infantis was the most frequent isolate, found in 22.6% of broiler fecal samples. Higher resistance rates were observed against oxytetracycline (82.0%), dihydrostreptomycin (77.9%), kanamycin (41.0%) and trimethoprim (35.2%). Resistance rates to ampicillin, ceftiofur, bicozamycin, chloramphenicol and nalidixic acid were <10%. CTX-M-2 β-lactamase producing S. enterica Senftenberg was found in the isolates obtained from one broiler fecal sample. This is the first report of cephalosporin-resistant Salmonella directly isolated from food animal in Japan.
doi:10.1186/1751-0147-51-35
PMCID: PMC2743694  PMID: 19703311
23.  Herd and cow characteristics affecting the odds of veterinary treatment for disease – a multilevel analysis 
Background
Research has indicated that a number of different factors affect whether an animal receives treatment or not when diseased. The aim of this paper was to evaluate if herd or individual animal characteristics influence whether cattle receives veterinary treatment for disease, and thereby also introduce misclassification in the disease recording system.
Methods
The data consisted mainly of disease events reported by farmers during 2004. We modelled odds of receiving veterinary treatment when diseased, using two-level logistic regression models for cows and young animals (calves and heifers), respectively. Model parameters were estimated using three procedures, because these procedures have been shown, under some conditions, to produce biased estimates for multi-level models with binary outcomes.
Results
Cows located in herds mainly consisting of Swedish Holstein cows had higher odds for veterinary treatment than cows in herds mainly consisting of Swedish Red cows. Cows with a disease event early in lactation had higher odds for treatment than when the event occurred later in lactation. There were also higher odds for veterinary treatment of events for cows in January and April than in July and October. The odds for veterinary treatment of events in young animals were higher if the farmer appeared to be good at keeping records. Having a disease event at the same date as another animal increased the odds for veterinary treatment for all events in young animals, and for lameness, metabolic, udder and other disorders, but not for peripartum disorders, in cows. There were also differences in the odds for veterinary treatment between disease complexes, both for cows and young animals.
The random effect of herd was significant in both models and accounted for 40–44% of the variation in the cow model and 30–46% in the young animal model.
Conclusion
We conclude that cow and herd characteristics influence the odds for veterinary treatment and that this might bias the results from studies using data from the cattle disease database based on veterinary practice records.
doi:10.1186/1751-0147-51-34
PMCID: PMC2736961  PMID: 19698112
24.  Cortisol secretion after adrenocorticotrophin (ACTH) and Dexamethasone tests in healthy female and male dogs 
Background
For the conclusive diagnosis of Cushing's Syndrome, a stimulating ACTH test or a low suppressive Dexamethasone test is used. Reports in other species than the dog indicate that plasma cortisol concentration after ACTH administration is affected by gender. We investigated the effect of gender on the cortisol response to ACTH and Dexamethasone tests in dogs.
Methods
Seven healthy adult Cocker Spaniels (4 females and 3 males) were assigned to a two by two factorial design: 4 dogs (2 females and 2 males) received IV Dexamethasone 0.01 mg/kg, while the other 3 dogs received an IV saline solution (control group). Two weeks later the treatments were reversed. After one month, ACTH was given IV (250 μg/animal) to 4 dogs (2 female and 2 males) while the rest was treated with saline solution (control group). Cortisol concentrations were determined by a direct solid-phase radioimmunoassay and cholesterol and triglycerides by commercial kits.
Results and Discussion
No effect of treatment was observed in metabolite concentrations, but females presented higher cholesterol concentrations. ACTH-treated dogs showed an increase in cortisol levels in the first hour after sampling until 3 hours post injection. Cortisol concentrations in Dexamethasone-treated dogs decreased one hour post injection and remained low for 3 hours, thereafter cortisol concentrations increased. The increase in cortisol levels from one to two hours post ACTH injection was significantly higher in females than males. In Dexamethasone-treated males cortisol levels decreased one hour post injection up to 3 hours; in females the decrease was more pronounced and prolonged, up to 5 hours post injection.
Conclusion
We have demonstrated that cortisol response to ACTH and Dexamethasone treatment in dogs differs according to sex.
doi:10.1186/1751-0147-51-33
PMCID: PMC2739526  PMID: 19686591
25.  Effect of yeast culture on milk production and metabolic and reproductive performance of early lactation dairy cows 
Background
The main objective of this study was to estimate the effect of supplementation with Saccaromyces cerevisiae (SC) (Yea-Sacc® 1026) on milk production, metabolic parameters and the resumption of ovarian activity in early lactation dairy cows.
Methods
The experiment was conducted during 2005/2006 in a commercial tied-house farm with an average of 200 milking Estonian Holstein Friesian cows. The late pregnant multiparous cows (n = 46) were randomly divided into two groups; one group received 10 g yeast culture from two weeks before to 14 weeks after calving. The groups were fed a total mixed ration with silages and concentrates. Milk recording data and blood samples for plasma metabolites were taken. Resumption of luteal activity was determined using milk progesterone (P4) measurements. Uterine bacteriology and ovarian ultrasonography (US) were performed and body condition scores (BCS) and clinical disease occurrences were recorded. For analysis, the statistical software Stata 9.2 and R were used to compute Cox proportional hazard and linear mixed models.
Results
The average milk production per cow did not differ between the groups (32.7 ± 6.4 vs 30.7 ± 5.3 kg/day in the SC and control groups respectively), but the production of milk fat (P < 0.001) and milk protein (P < 0.001) were higher in the SC group. There was no effect of treatment on BCS. The analysis of energy-related metabolites in early lactation showed no significant differences between the groups. In both groups higher levels of β-hydroxybutyrate (BHB) appeared from days 14 to 28 after parturition and the concentration of non-esterfied fatty acid (NEFA) was higher from days 1–7 post partum (PP). According to US and P4 results, all cows in both groups ovulated during the experimental period. The resumption of ovarian activity (first ovulations) and time required for elimination of bacteria from the uterus did not differ between the groups.
Conclusion
Supplementation with SC had an effect on milk protein and fat production, but did not influence the milk yield. No effects on PP metabolic status, bacterial elimination from the uterus nor the resumption of ovarian activity were found.
doi:10.1186/1751-0147-51-32
PMCID: PMC2738670  PMID: 19650887

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