Comparison of timing of relapse in dogs with nonassociative immune-mediated hemolytic anemia, thrombocytopenia, or polyarthritis.

BACKGROUND: Relapse is a clinical concern in dogs diagnosed with immune-mediated hemolytic anemia (IMHA), thrombocytopenia (ITP), or polyarthritis (IMPA). The average time to relapse is unknown, and evidence that vaccination is associated with disease relapse is lacking. HYPOTHESIS/OBJECTIVES: Compare the incidence of relapse in groups of dogs with IMHA, ITP, or IMPA over a 24-month period after diagnosis and compare proportions of dogs that received vaccines in those dogs that did and did not relapse. ANIMALS: One hundred sixty client-owned dogs (73 with IMHA, 55 with ITP, 32 with IMPA). METHODS: Medical records of dogs were reviewed with the goal of following cases for a minimum of 2 years. Incidence of relapse was calculated for each disease, and relapse rates in dogs that were or were not vaccinated after diagnosis were compared. RESULTS: Relapse rates at 12 months differed significantly among disease groups (P = .02), with a higher rate for IMPA (35%) compared to IMHA (11%) or ITP (11%). Relapse rate at 24 months was 41% for IMPA, 18% for IMHA, and 23% for ITP. Ninety percent of IMPA relapses occurred in the first 12 months after diagnosis, compared with 56% for IMHA and 50% for ITP. Vaccine administration after diagnosis was not associated with relapse (P = .78). CONCLUSIONS AND CLINICAL IMPORTANCE: Risk of disease relapse in IMPA is highest in the first year after diagnosis, with a higher relapse rate compared with IMHA and ITP. The role of vaccination in disease relapse remains unclear.

Immune-mediated polyarthritis and anterior uveitis secondary to zonisamide administration in a dog with refractory epilepsy.

The objective of this article is to describe a case of suspected zonisamide-induced immune-mediated polyarthritis (IMPA) and anterior uveitis in a dog. A 7-year-old male neutered Siberian Husky with a history of refractory idiopathic epilepsy was presented for cluster seizures. Following the addition of zonisamide to the antiepileptic regime, the dog developed new IMPA and anterior uveitis. Within a few weeks of discontinuation of the zonisamide, the dog's IMPA and anterior uveitis resolved. These immune-mediated conditions were thus presumed to be an idiosyncratic reaction to zonisamide. To our knowledge, this is the first report of IMPA and anterior uveitis in dogs associated with zonisamide administration at its recommended dose.

Detection and disease diagnosis trends (2017-2022) for Streptococcus suis, Glaesserella parasuis, Mycoplasma hyorhinis, Actinobacillus suis and Mycoplasma hyosynoviae at Iowa State University Veterinary Diagnostic Laboratory.

BACKGROUND: Accurate measurement of disease associated with endemic bacterial agents in pig populations is challenging due to their commensal ecology, the lack of disease-specific antemortem diagnostic tests, and the polymicrobial nature of swine diagnostic cases. The main objective of this retrospective study was to estimate temporal patterns of agent detection and disease diagnosis for five endemic bacteria that can cause systemic disease in porcine tissue specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) from 2017 to 2022. The study also explored the diagnostic value of specific tissue specimens for disease diagnosis, estimated the frequency of polymicrobial diagnosis, and evaluated the association between phase of pig production and disease diagnosis. RESULTS: S. suis and G. parasuis bronchopneumonia increased on average 6 and 4.3%, while S. suis endocarditis increased by 23% per year, respectively. M. hyorhinis and A. suis associated serositis increased yearly by 4.2 and 12.8%, respectively. A significant upward trend in M. hyorhinis arthritis cases was also observed. In contrast, M. hyosynoviae arthritis cases decreased by 33% average/year. Investigation into the diagnostic value of tissues showed that lungs were the most frequently submitted sample, However, the use of lung for systemic disease diagnosis requires caution due to the commensal nature of these agents in the respiratory system, compared to systemic sites that diagnosticians typically target. This study also explored associations between phase of production and specific diseases caused by each agent, showcasing the role of S. suis arthritis in suckling pigs, meningitis in early nursery and endocarditis in growing pigs, and the role of G. parasuis, A. suis, M. hyorhinis and M. hyosynoviae disease mainly in post-weaning phases. Finally, this study highlighted the high frequency of co-detection and -disease diagnosis with other infectious etiologies, such as PRRSV and IAV, demonstrating that to minimize the health impact of these endemic bacterial agents it is imperative to establish effective viral control programs. CONCLUSIONS: Results from this retrospective study demonstrated significant increases in disease diagnosis for S. suis, G. parasuis, M. hyorhinis, and A. suis, and a significant decrease in detection and disease diagnosis of M. hyosynoviae. High frequencies of interactions between these endemic agents and with viral pathogens was also demonstrated. Consequently, improved control programs are needed to mitigate the adverse effect of these endemic bacterial agents on swine health and wellbeing. This includes improving diagnostic procedures, developing more effective vaccine products, fine-tuning antimicrobial approaches, and managing viral co-infections.

Synergistic pathogenicity of avian orthoreovirus and Staphylococcus aureus on SPF chickens.

Avian arthritis is a relatively common disease in the poultry industry, the cause of which is complex. Bacterial arthritis is often caused by infection of Staphylococcus aureus (S. aureus), whereas viral arthritis is caused by avian orthoreovirus (ARV). To investigate the infection of S. aureus and ARV in cases of avian arthritis, a total of 77 samples characterized by arthritis were collected and detection. The results showed that 68.83% of the samples were positive for ARV, and 66.23% were positive for S. aureus. Among them, the ARV mono-infection rate was 22.08%, the S. aureus mono-infection rate was 19.48%, and ARV and S. aureus co-infection rate was 45.45%, indicating that ARV and S. aureus co-infection is common in arthritis cases. To further investigate the synergistic pathogenicity of ARV and S. aureus, ARV and S. aureus were used to mono-infect, co-infect, and (or) sequential infect SPF chickens and the clinical indications, pathologic changes, ARV load, S. aureus bacterial distribution, and cytokine level of the challenged chickens were evaluated. Decreased weight gain, increased mortality, and difficulties in standing were observed in all dual-infected groups and the singular-infected group. There were significantly more severe macroscopic and microscopic hock lesions, and larger amounts of a wider range of tissue distribution of ARV antigens and S. aureus bacterial distribution in the dual-infected groups compared to the single-infected and control groups. Cytokine detection showed a significant change in IFN-γ, IL-1ß, and IL-6 levels in the infected groups, especially in the ARV-S. aureus co-infection, and (or) sequential infection groups, compared with the control group. Hence, ARV and S. aureus synergistically increased mortality in infected chickens, potentiated the severity of arthritis, and increased the amount of ARV RNA in tendons.

Co-circulation of multiple genotypes of ARV in poultry in Anhui, China.

ABSTRACTPoultry production in China has been experiencing a high incidence of broiler arthritis /tenosynovitis caused by avian orthoreovirus (ARV) since 2013. In the spring of 2020 severe arthritis cases from broiler flocks were identified in a large-scale commercial poultry company in Anhui Province, China. Diseased organs from dead birds were sent for diagnosis to our laboratory. ARVs, including seven broiler-isolates and two breeder-isolates, were successfully harvested and sequenced. Interestingly, the genotypes of ARVs isolated from infected chickens were inconsistent between different flocks, or even between different houses on the same flocks. Pathogenicity testing in chicks confirmed that the seven broiler-isolates were pathogenic strains, which could cause arthritis in infected chickens. Subsequently, a total of 89.66% serum samples collected from apparently healthy adult broiler flocks not vaccinated against ARV tested positive for ARV antibodies, suggesting that low and high virulence reovirus strains may be co-circulating in the farm. To this end, we collected dead embryos of unhatched chicken eggs for pathogen tracing, and the two ARV breeder-isolates isolated indicated that vertical transmission from breeders to progeny should not be underestimated for the prevalence of ARV within broiler flocks. The findings have implications for the evidenced-based formulation of prevention and control strategies.

Onchocerca sp. in an imported Zangersheide gelding causing suspensory ligament desmitis.

A 5-year-old imported Zangersheide gelding was evaluated for SC swellings over both forelimbs and lameness localized to the distal metacarpus. Ultrasound examination of the SC masses was compatible with verminous granulomas. Linear hyperechoic foci were present within the suspensory ligament branches of both forelimbs, suggestive of ligamentous parasitic infiltrates. A diagnosis of onchocerciasis was confirmed on biopsy of a SC mass. The gelding was treated with ivermectin and a tapering course of PO dexamethasone but was eventually euthanized. Necropsy confirmed the presence of SC eosinophilic granulomas and degenerative suspensory ligament desmitis, both with intralesional nematodes. Given the location and appearance of the nematode, a diagnosis of Onchocerca sp., most likely O. reticulata, was made. Onchocerciasis should be included as a differential diagnosis for multifocal suspensory ligament desmitis with these sonographic characteristics when paired with SC masses in imported European Warmbloods.

Brevundimonas vesicularis isolation from a Labrador Retriever with Bacteremia, Endocarditis, Spinal Epidural Empyema, and Polyarthritis.

A 7 yr old spayed female Labrador retriever was evaluated for progressive nonambulatory tetraparesis, obtundation, joint pain, and pyrexia. The dog was diagnosed with spinal epidural empyema, bacteremia, endocarditis, and polyarthritis based on magnetic resonance imaging, echocardiography, joint fluid analysis, and blood culture. Blood culture isolated a rare and atypical pathogen, Brevundimonas vesicularis in conjunction with Escherchia coli. The patient was treated with a 10 mo antibiotic course, and clinical signs quickly resolved. This is the first report of B vesicularis in association with bacteremia, endocarditis, spinal empyema, and polyarthritis in a dog.

Survey of the knowledge and perceptions of horse owners in Ireland of common clinical conditions and their impact.

BACKGROUND: As the primary decision-maker for their horse's health and welfare, owners' knowledge of clinical conditions may impact their horse's health. Anecdotal evidence suggests that the emotional impact of equine illness on the owner can be severe but research is lacking. OBJECTIVES: To evaluate horse owners' self-declared knowledge of eight common equine health conditions and perceptions of the quality of information available; to ascertain respondents' perceptions of the severity of impact on their horse of the conditions and potential emotional impact on themselves and to establish the factors of greatest concern to owners when their horse has a health condition and influential factors on end-of-life decisions. STUDY DESIGN: Online survey of horse owners. METHODS: An online survey comprising three sections was created: respondent demographics; vignettes of clinical conditions; concerns and decision-making regarding illness and euthanasia. Vignettes focused on arthritis; Pars Pituitary Intermedia Dysfunction; Equine Metabolic Syndrome (EMS); gastric ulcers; high intestinal worm burden; dermatophilosis ('mud rash'); quidding and head tossing; and equine asthma. Respondents were self-selecting. The survey was circulated for completion by horse owners residing in Ireland and Northern Ireland obtaining 491 valid responses. RESULTS: Respondents declared that they had the highest knowledge of mud rash, with 84.1% rating their knowledge as very good compared to 42% of respondents for EMS. There was positive correlation between the perceived impact on their horse and emotional impact on the owner for all conditions ranging from weak (arthritis 0.36, P < 0.001) to strong (EMS 0.62, P < 0.001). Pain, discomfort, and quality of life were reported as the most common concerns when their horse has a medical condition or when considering euthanasia. MAIN LIMITATIONS: Potential bias among respondents towards computer literate owners, with good literacy and interest in equine health conditions. CONCLUSIONS: Knowledge of equine health conditions, perceived impact of conditions on the horse and emotional impact on their owners varied significantly between conditions.

Description and outcome of dogs with primary immune-mediated polyarthritis: 73 cases (2012-2017).

OBJECTIVES: To provide a description of primary idiopathic immune-mediated polyarthritis, including long-term outcome and relapse rates, for dogs starting treatment with corticosteroids alone or corticosteroids with a second immunosuppressant. MATERIALS AND METHODS: Medical records were reviewed between January 2012 and December 2017 to identify dogs diagnosed with primary immune-mediated polyarthritis. Data including signalment, clinicopathological findings, type and duration of treatment, relapse and outcome were recorded. RESULTS: Seventy-three dogs were included. Fifty-four dogs were started on corticosteroid monotherapy (an additional immunosuppressant was introduced later in 27/54 dogs) and 19 dogs were treated with multi-modal immunosuppression from the outset. Ninety-five percent (69/73) of dogs responded favourably to therapy although death was attributed to immune-mediated polyarthritis in 19% (14/73) of dogs. Relapse of clinical signs was reported in 53% (39/73) dogs (31/39 while on treatment), with multiple relapses observed in 17 dogs. Complete cure (permanent withdrawal of immunosuppressive medication) was achieved in 46 dogs (63%). Overall, 81% of dogs had a well-managed disease for an extended timeframe (≥1131 days). Fourteen of 19 (74%) dogs that started treatment with multi-modal immunosuppression and 32 of 54 (59%) started on corticosteroids alone achieved a complete cure. CLINICAL SIGNIFICANCE: This study provides extended follow-up information for a large cohort of dogs with primary immune-mediated polyarthritis. Immunosuppressive therapy was discontinued in the majority of dogs but disease-associated mortality remains high.

A new S. suis serotype 3 infection model in pigs: lack of effect of buprenorphine treatment to reduce distress.

BACKGROUND: Streptoccocus suis (S. suis) is a major porcine pathogen causing meningitis, septicemia, arthritis and endocarditis. These diseases severely impair welfare of pigs. Experimental studies in pigs are important to better understand the pathogenesis and to identify protective antigens, as so far there is no vaccine available protecting against various serotypes (cps). Due to the severity of disease, application of appropriate refinement strategies in experimental S. suis infections is essential to reduce distress imposed on the piglets without jeopardizing the scientific output. The objectives of this study were to evaluate buprenorphine treatment as a refinement measure and serum cortisol levels as a distress read out parameter in a new S. suis cps3 infection model in pigs. RESULTS: Intravenous application of 2 × 108 CFU of S. suis cps3 (sly+, mrp+) to 6-week-old piglets led to severe morbidity in approximately 50% of the animals. Main pathological findings included suppurative meningoencephalitis and arthritis as well as fibrinosuppurative endocarditis. Buprenorphine treatment (0.05 mg/kg every 8 h) did not prevent signs of severe pain, high clinical scores, moderate to severe pathologies or high levels of serum cortisol in single severely affected piglets. Significant differences in the course of leukocytosis, induction of specific antibodies and bactericidal immunity were not recorded between groups with or w/o buprenorphine treatment. Of note, clinically unobtrusive piglets showed serum cortisol levels at 2 and 5 days post infectionem (dpi) comparable to the levels prior to infection with cps3. Cortisol levels in serum were significantly increased in piglets euthanized due to severe disease in comparison to clinically unobtrusive pigs. CONCLUSIONS: Different clinical courses and pathologies are induced after intravenous challenge of piglets with 2 × 108 CFU of this S. suis cps3 strain. The chosen protocol of buprenorphine application does not prevent severe distress in this infection model. Important parameters of the humoral immune response, such as the level of IgM binding to S. suis cps3, do not appear to be affected by buprenorphine treatment. Serum cortisol is a meaningful parameter to measure distress in piglets experimentally infected with S. suis and to evaluate refinement strategies. In this intravenous model, which includes close clinical monitoring and different humane endpoints, clinics and cortisol levels suggest convalescence in surviving piglets within 5 days following experimental infection.

Prevalence of antinuclear antibodies and rheumatoid factor titers in dogs with arthritis secondary to leishmaniosis (Leishmania infantum).

Dogs with infectious arthritis may occasionally exhibit positive serum antinuclear antibody (ANA) and rheumatoid factor (RF) titers; however, relevant data are sparse for arthritis secondary to canine leishmaniosis (CanL) caused by Leishmania infantum. We determined the prevalence of positive serum ANA and RF titers in dogs with arthritis secondary to CanL. Blood samples from adult, client-owned dogs with purulent arthritis secondary to CanL, without any comorbidities, were collected for diagnostic purposes. Serum ANA titers were measured by immunoperoxidase test and RF titers by the Rose-Waaler latex test. Twelve of 23 dogs enrolled prospectively in our study had clinical arthritis, and 11 of 23 had subclinical arthritis. Based on LeishVet clinical staging, 7 dogs had clinical stage II disease, 11 had clinical stage III disease, and 5 had stage IV. None of the 23 dogs was seropositive for ANA; 3 of 23 were positive for RF. ANA and/or RF seropositivity, in dogs with CanL-associated arthritis, appears to be weak, if present at all. Based on our results, positive serum ANA and RF titers should not be expected in dogs with arthritis secondary to CanL.

Feline non-erosive immune-mediated polyarthritis: a multicentre, retrospective study of 20 cases (2009-2020).

CASE SERIES SUMMARY: Cats with non-erosive immune-mediated polyarthritis (IMPA) were identified from seven referral hospitals between 2009 and 2020 for a multicentre retrospective case series. Data were obtained from hospital records and referring veterinarians were contacted for follow-up. Twenty cases were identified: 12 castrated males (60%), one entire male (5%) and seven spayed females (35%). Common clinical signs included lameness (n = 20/20) and pyrexia (n = 10/18). Three cats presented with and two cats developed ligament laxity during treatment. Thirteen cats (65%) were diagnosed with non-associative IMPA and seven (35%) with associative IMPA. Comorbidities identified included chronic enteropathy (n = x/7), feline immunodeficiency virus (n = x/7) feline herpesvirus (n = x/7), bronchopneumonia (n = x/7) and discospondylitis (n = x/7). Sampling of the tarsal joints most frequently identified an increased proportion of neutrophils, consistent with IMPA. Eighteen cats (90%) received immunosuppressants. Eleven cats were started on prednisolone; eight had a poor response resulting in the addition of a second agent, euthanasia or acceptance of the persisting signs. One cat received ciclosporin and required an alternative second agent owing to adverse effects. Five cats were started on prednisolone and ciclosporin; three had a poor response and required an alternative second agent. One cat received prednisolone and chlorambucil and had a good response. Two cats (10%) received meloxicam and had a good response, although the clinical signs recurred when medication was tapered. A good outcome was achieved in 14/20 cats (70%) with IMPA. In the cats with a poor outcome 4/6 were euthanased and 2/6 had chronic lameness. RELEVANCE AND NOVEL INFORMATION: Prognosis for feline IMPA can be good. Multimodal immunosuppression was often required. IMPA should be considered in lame cats, with or without pyrexia, when there is no evidence of trauma or infection. The tarsal joints should be included in the multiple joints chosen for sampling. Ligament laxity can occur in non-erosive feline IMPA.

Point prevalence and clinical course of proteinuria in dogs with idiopathic non-erosive immune-mediated polyarthritis.

OBJECTIVES: To describe the point prevalence and clinical course of proteinuria in dogs diagnosed with idiopathic non-erosive immune-mediated polyarthritis. MATERIALS AND METHODS: Cases presenting to a single referral centre with a diagnosis of idiopathic non-erosive immune-mediated polyarthritis were retrospectively recruited from January 2009 to August 2018. Data including signalment, urinalysis, clinicopathological results, cytology from arthrocentesis, treatment and long-term follow-up were analysed. Dogs were defined as: non-proteinuric (UPC <0.2), borderline proteinuric (UPC 0.2-0.5) or overtly proteinuric (UPC >0.5). RESULTS: Fifty-eight dogs met the inclusion criteria. Twenty-two dogs were overtly proteinuric (38%), eight dogs were borderline proteinuric (14%) and 28 dogs were non-proteinuric (48%). Repeated urinalysis was performed in nine of 12 dogs with UPC greater than 2.0. The UPC decreased in all nine dogs, with the UPC decreasing to less than 0.5 in 44% of dogs. A greater than 50% decrease in UPC was noted in 44% of dogs, despite seven of nine (77%) receiving prednisolone as either monotherapy or in conjunction with an adjunctive immunosuppressive medication. CLINICAL SIGNIFICANCE: Proteinuria was common in this cohort of dogs diagnosed with primary idiopathic non-erosive immune-mediated polyarthritis. The use of prednisolone does not appear to be contraindicated in proteinuric dogs with idiopathic non-erosive immune-mediated polyarthritis.

Natural cases of polyarthritis associated with feline calicivirus infection in cats.

The limping syndrome is occasionally reported during acute feline calicivirus (FCV) infections or as consequence of vaccination. In this retrospective study, three clinical cases of lameness in household cats naturally infected by FCV were described and phylogeny of the virus were investigated by analysing the hypervariable E region of the ORF2 viral gene. Cats were diagnosed with polyarthritis and FCV RNA or antigens were detected in symptomatic joints. One cat, euthanized for ethical reasons, underwent a complete post-mortem examination and was subjected to histopathological and immunohistochemical investigations. No phylogenetic subgrouping were evident for the sequenced FCV. Histopathology of the euthanized cat revealed diffuse fibrinous synovitis and osteoarthritis eight months after the onset of lameness and the first detection of FCV RNA, supporting the hypothesis of a persistent infection. FCV was demonstrated by immunohistochemistry in synoviocytes and fibroblasts of the synovial membranes. This study provides new data on the occurrence of polyarthritis in FCV-infected cats, demonstrates by immunohistochemistry the presence of FCV in the synovial membranes of a cat with persistent polyarthritis and supports the absence of correlation between limping syndrome and phylogenetic subgrouping of viruses.

Mycoplasma bovis-pneumonia and polyarthritis in feedlot calves in Argentina: First local isolation.

Bovine respiratory disease (BRD) is one of the most frequent clinical concerns in weaned calves after their arrival at the feedlot. This work reports the first local isolation of Mycoplasma bovis from feedlot calves with pneumonia and polyarthritis in Argentina. Twenty four out of 545 calves showed progressive, subacute to chronic respiratory distress, coughing, and fever. Thirty percent of the affected calves also showed lameness and swelling of elbow or carpal, and knee or tarsal joints. Five necropsies were performed and severe multifocal to coalescent pulmonary nodules, containing white-yellowish caseous exudate encircled by fibrous tissue, and fibrinonecrotic arthritis and tenosynovitis were detected. Mycoplasma was isolated from lung and joint samples. The 16S-23S rRNA ITS consensus sequence obtained from these isolates showed 100% similarity with the same region of M. bovis strains. Since there are no commercially available vaccines in the region for the prevention and control of M. bovis pneumonia and arthritis, surveillance is a priority to reduce the source of disease to naïve animals.

Bacterial polyarthritis in post-weaning pigs in a high-density swine breeding area in Italy.

We assessed the bacterial agents found in 8-12-wk-old post-weaning pigs with arthritis. The bodies of 178 post-weaning pigs from 90 farms (average of 2 pigs/farm) with recurrent problems of lameness and swollen joints in a high-density breeding area were submitted for autopsy and sampled for further bacterial investigation. The most common articular gross lesions and histopathologic findings were serofibrinous (95 of 178; 53%) or serous (65 of 178; 37%) arthritis; suppurative lesions were less frequent (18 of 178; 10%). In 133 of 178 (74.7%) cases, a bacterial agent was detected in joints. Mycoplasma hyorhinis was the most common bacterium detected (82 of 133; 61.6%). Haemophilus parasuis and Streptococcus spp. were observed in 27 of 133 (20.3%) and 24 of 133 (18.0%) cases, respectively. Other bacteria in the 113 cases, considered less important, in order of their low frequency, were Mycoplasma spp. (13; 9.8%), Trueperella pyogenes (11; 8.2%), Mycoplasma hyosynoviae (4; 3.0%), Staphylococcus spp. (3; 2.2%), Escherichia coli (2; 1.5%), and Actinobacillus spp. (2; 1.5%). Our results highlight the primary role of M. hyorhinis compared to other microorganisms involved in young pigs with arthritis.

Comparative pathogenesis of turkey reoviruses.

Turkey reoviruses have been implicated in multiple disease syndromes resulting in significant economic losses to the turkey industry. It has been known for decades that turkey enteric reovirus (TERV) is involved in poult enteritis complex, but turkey arthritis reovirus (TARV), the causative agent of tenosynovitis in turkeys, emerged in 2011. In 2019, we isolated reovirus from several cases of hepatitis in turkeys and tentatively named it turkey hepatitis reovirus (THRV). The comparative pathogenesis of these viruses, and correlation with their genetic make-up (if any), is not known. In this study, we inoculated nine groups of 1-week-old turkey poults with two THRV, five TARV and two TERV via oral route. A tenth group served as a negative control. A subset of birds from each group was euthanised at 3, 5, 7, 14, 21, and 28 days post-inoculation (dpi). Tissues were collected for histology and real-time RT-PCR. All nine viruses were found to be enterotropic; the virus gene copy number in the intestine reached a peak at 5 dpi followed by a sharp decline at 7 dpi. All viruses caused a significant decline in body weight gain of birds as compared to the negative control group. Both TARV and THRV strains replicated in tendons and produced histologic lesions consistent with tenosynovitis. Hepatic lesions were produced by THRV only and the virus was re-isolated from liver and spleen of inoculated birds fulfilling Koch's postulates. The results of this study should be helpful in facilitating diagnosis and designing future mitigation plans.

Dynamics of Mycoplasma bovis in Dutch dairy herds during acute clinical outbreaks.

Mycoplasma bovis (M. bovis) can cause serious illness in cattle, presenting as arthritis and mastitis in dairy cows and pneumonia, arthritis and otitis media in calves. This study aimed to provide insight into the dynamics of M. bovis within dairy herds, experiencing an acute outbreak in dairy cows. Twenty farms were followed with laboratory testing of suspected dairy cows. Each outbreak farm was sampled five times, at 2-3 week intervals, sampling blood and milk and conjunctival fluid from clinically suspected dairy cows and healthy animals from three different age groups: dairy cows, young stock (7-24 months) and calves (1-6 months). Additionally, bulk tank milk was sampled every visit and environmental samples were taken on the first and last visits. The presence of M. bovis was tested by evaluating antibody titres in blood, bacterial DNA in conjunctival fluid and environmental samples and viable bacteria in milk samples. All data were analysed using logistic regression models, corrected for repeated sampling and within-herd correlation. Sixty percent (12/20) of the herds showed a combination of arthritis and mastitis, while other herds experienced only clinically mastitis (3/20) or arthritis (5/20). From the time an outbreak was confirmed, M. bovis infection was not only present in dairy cows, but also in young stock and calves (80% of the farms). Laboratory tests also confirmed the presence of M. bovis in healthy animals. The M. bovis PCR levels of calves and young stock were highly correlated at all visits (rtotal = 0.81, P < 0.01). Furthermore, M. bovis was present in the environment of the animals. At the end of the 3-month study period, none of the 20 clinical outbreak farms were M. bovis-'negative', based on laboratory testing, although hardly any clinical cases were observed at that time.

Virulence and Inoculation Route Influence the Consequences of Mycoplasma hyorhinis Infection in Bama Miniature Pigs.

Mycoplasma hyorhinis is a widespread pathogen in pig farms worldwide. Although the majority of M. hyorhinis-colonized pigs have no apparent clinical disease, the pathogen can induce diseases such as polyserositis, arthritis, and eustachitis in some cases. To explore the mechanisms for the occurrence of these diseases, we challenged 4 groups of Bama miniature pigs with M. hyorhinis isolated from pigs without clinical symptoms (non-clinical origin [NCO] strain) or with typical clinical symptoms (clinical origin [CO] strain) and investigated the impacts of different strains and inoculation routes (intranasal [IN], intravenous [IV] + intraperitoneal [IP], and IV+IP+IN) on disease induction. Another group of pigs was set as a negative control. Pigs inoculated with the CO strain through a combined intravenous and intraperitoneal (IV+IP) route showed a significant decrease in average daily weight gain (ADWG), serious joint swelling, and lameness compared with the pigs in the negative-control group. Furthermore, this group developed moderate-to-severe pericarditis, pleuritis, peritonitis, and arthritis, as well as high levels of IgG and IgM antibodies. Pigs inoculated IV+IP with the NCO strain developed less marked clinical, pathological changes and a weaker specific antibody response compared with the pigs inoculated with the CO strain. The challenging results of the NCO strain via different routes (IV+IP, IV+IP+IN, and IN) indicated that the combined route (IV+IP) induced the most serious disease compared to the other inoculation routes. Intranasal inoculation induced a smaller decrease in ADWG without obvious polyserositis or arthritis. These data suggest that differences in both strain virulence and inoculation route affect the consequences of M. hyorhinis infection. IMPORTANCE Mycoplasma hyorhinis is a widespread pathogen in pig farms worldwide. The mechanisms or conditions that lead to the occurrence of disease in M. hyorhinis-infected pigs are still unknown. The objective of this study was to evaluate the impact of differences in the virulence of strain and the inoculation route on the consequences of M. hyorhinis infection.

The presence of adhesion factors NOX, α-enolase, TrmFO, P27, and VpmaX in Mycoplasma bovis wild isolates in Japan.

Background: Mycoplasma bovis causes various diseases such as bronchopneumonia, otitis media, arthritis, and mastitis in cattle. Mycoplasma bovis is often isolated from the deep pharynges of healthy cattle and is generally considered not to cause clinical symptoms while in the upper respiratory tract. In mycoplasma infections, adhesion to the host cells is a crucial step. In recent years, five new adhesins, NOX, α-enolase, TrmFO, P27, and VpmaX, have been reported in M. bovis strains from pneumonia cases. However, the presence of these adhesins in wild isolates has not been established. Aim: This study aimed to investigate the presence of these adhesin genes in wild isolates isolated from cattle nasal cavities and lesion sites (pneumonia, otitis media, arthritis, and mastitis) in various regions in Japan and clarify the relationship between adhesion and the symptoms caused by M. bovis infection. Methods: A total of 141 M. bovis wild isolates isolated from nasal cavities (healthy or sick cattle), lungs with pneumonia, ears with otitis media, joint fluids of arthritic animals, and milk of mastitic animals. Mycoplasma bovis type strain PG45 was also used. Specific polymerase chain reaction reactions were performed to detect nox, α-enolase, trmFO, P27, and vpmaX, which are adhesins of M. bovis. Results: This study reports 139 M. bovis wild isolates were positive for nox, α-enolase, trmFO, P27, and vpmaX, while two isolates each lacked α-enolase or P27 genes. Mycoplasma bovis PG45 also had all five adherens genes. Conclusion: Almost all M. bovis wild isolates possessed all nox, α-enolase, trmFO, P27, and vpmaX genes regardless of the lesion site or region of origin. This means no relationship was found between the presence of the five adhesins and lesion sites in M. bovis and M. bovis isolated from the nasal cavities of asymptomatic cattle have the same numbers and types of adhesins as isolates from symptomatic lesion sites (pneumonia, otitis media, arthritis, and mastitis). This suggests that not only M. bovis isolates from pulmonary lesions, but also M. bovis existing in the nasal cavity has the potential to causes symptoms in the host.