Procalcitonin and carbonylated protein concentrations in equine synovial fluid

Early diagnosis of joint diseases is fundamental for prompt and appropriate management, particularly in septic arthritis. Procalcitonin (PCT) and protein carbonylated content (PCC) have been investigated in both human and veterinary medicine. An increase in PCT has been shown in infectious bacterial diseases, while higher levels of PCC have been shown in inflammatory pathologies characterized by oxidative damage. This study evaluated PCT and PCC in plasma and synovial fluid (SF), in healthy and pathological equine joints, affected by different types of arthropathy. Twenty-nine joints were evaluated and underwent orthopedic, radiographic, ultrasonographic and SF evaluation. The joints were divided in three groups: healthy, septic, and non-septic arthritis. PCT and PCC were measured in horse plasma and SF. Data distribution was evaluated and results were expressed as median, quartile values. Statistical differences in SF values among groups and correlations were assessed between plasma and SF of both PCT and PCC. The groups of joint disease included: 8/29 healthy, 13/29 non-septic and 8/29 septic. Significant differences were obtained for SF PCC and plasma PCT between healthy and septic joints, while no differences were found for plasma PCC and SF PCT. A positive correlation was found between plasma and SF PCT. To the best of our knowledge, this is the first study reporting PCT in equine SF. SF PCC could be a useful biomarker to differentiate between septic and healthy joints.

Genetic characterization of newly emerging avian reovirus variants in chickens with viral arthritis/tenosynovitis in Israel

In recent years, new avian reovirus (ARV) variants caused a variety of symptoms in chickens worldwide, the most important of which was Viral arthritis/tenosynovitis which caused substantial economic losses and has become a concern to the worldwide chicken industry. In this study, we characterized emerging ARV variants in Israel and analyzed their genetic relationship with reference strains. One hundred thirty-four ARV variants were isolated from tendons and synovial fluids of commercial broiler chickens with signs of arthritis/tenosynovitis. Phylogenetic analysis of the partial segment of the sigma C (σC) gene confirmed that these field isolates from Israel could be clustered into all six known clusters. The majority of ARV isolates in Israel belonged to the genotypic cluster 5 (GC5). The strains in this study had a low sequence identity when compared to the commercial vaccine (strain S1133). The findings of this study demonstrated the genetic diversity of ARV strains in Israel from 2015 to 2022. It is reasonable to conclude from the preliminary results of this investigation that Israel has not been subject to selection pressure or the emergence of new ARV variants since the introduction of the live vaccine (ISR-7585). Due to the ongoing emergence of ARV variants, a robust epidemiological monitoring program supported by molecular biology techniques is required to track ARV strains in Israeli poultry flocks.

Subchondral bone sequestrum formation in the proximal intra-articular and osteochondral region of the third metatarsal bone of an Appaloosa mare treated for septic arthritis

OBJECTIVE

To raise awareness of the potential for intra-articular subchondral bone sequestrum formation secondary to a traumatic or septic process to enable more rapid identification of this uncommon but possible outcome in future cases.

ANIMAL

A client-owned 12-year-old Appaloosa mare.

CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES

The mare had a wound to the lateral aspect of the fourth metatarsal bone (MT4) that communicated with the distal tarsal joints. Radiographs revealed a displaced, comminuted fracture of MT4.

TREATMENT AND OUTCOME

The horse underwent aggressive debridement of the wound and MT4 as well as, on 2 occasions, needle joint lavage. Systemic, regional, and IA antibiotic therapy was also performed together with a bone graft from the tuber coxae. The horse's comfort improved, and the wound appeared to be healing. Five weeks following discharge, the horse re-presented with a non-weight-bearing lameness and radiographs revealed marked osteomyelitis of the tarsometatarsal and distal intertarsal joints. Postmortem examination of the limb identified a sequestrum within the proximal articular surface of the third metatarsal bone.

CLINICAL RELEVANCE

The present report highlights the importance of arthroscopic lavage to visualize the cartilage surface and the benefits of advanced imaging to detect associated changes within the bone earlier than conventional radiographs. To our knowledge, no reports exist of intra-articular subchondral bone sequestra in the tarsometatarsal joint in horses.

An update on joint ill in sheep

This focus article has been prepared by Vanessa Swinson of the APHA Small Ruminant Expert Group.

Flock-level risk factors for outbreaks of infectious arthritis in lambs, Norway 2018

BACKGROUND

Outbreaks of infectious arthritis in young lambs associated with Streptococcus dysgalactiae subspecies dysgalactiae (SDSD) lead to reduced animal welfare, increased use of antibiotics and economic losses for sheep farmers. Understanding risk factors is essential when developing strategies to prevent such outbreaks. This questionnaire-based cross-sectional study classified sheep flocks of respondents as cases or controls. Flock-level risk factors for outbreaks of infectious arthritis were assessed using a multivariable logistic regression model.

RESULTS

Eighty-four of 1498 respondents (5.6%) experienced an outbreak of infectious arthritis in their flock in 2018, the year of study. Factors associated with a higher risk of outbreak were larger flock size (OR 1.3, 95% CI 1.1-1.4, per 100 lambs), plastic mesh flooring in the lambing pen (OR 3.0, 95% CI 1.7-5.3) and a lambing percentage greater than 200 (OR 2.0, 95% CI 1.1-3.5). Flocks where farmers observed infections around the ear tags of lambs also had an increased risk of outbreak (OR 2.6, 95% CI 1.6-4.3).

CONCLUSIONS

The risk factors identified in this study are characteristic of modern and intensively managed sheep farms in Norway. A distinguishing feature of Norwegian sheep farming is winter housing and indoor lambing. One might expect that this in itself is a risk factor because of high stocking densities during lambing. However, outbreaks of infectious arthritis in young lambs are reported by the industry to be a more recent phenomenon. The current study indicates that intensification of indoor management systems with larger flocks and higher production per ewe may predispose to outbreaks. The results provide a basis for further studies on transmission dynamics of SDSD in sheep flocks with indoor lambing.

Use of serum amyloid A in serum and synovial fluid to detect eradication of infection in experimental septic arthritis in horses

While serum amyloid A (SAA) has been investigated as a potential marker for septic arthritis in horses, no study has reported on whether SAA can be used to detect eradication of joint infection. Therefore, the objective of this study was to investigate whether the eradication of joint infection in experimentally induced septic arthritis in horses can be detected using serum and synovial fluid SAA. A total of 17 horses were randomly assigned to 3 groups. A middle carpal joint of each horse was injected with saline (control group, n = 3), lipopolysaccharide (LPS) (nonseptic synovitis group, n = 6), or Escherichia coli (septic arthritis group, n = 8) on day 0. Starting on day 1, horses underwent treatment for septic arthritis. Sequential samples of serum and synovial fluid were collected, and quantification of SAA was carried out. Concentrations of serum and synovial fluid SAA were compared among groups and time points. A concurrent study was conducted and determined that infection was eradicated on day 4 in this experimental model of septic arthritis. Concentrations of serum and synovial fluid SAA rapidly increased after inoculation of E. coli and were highest on day 3 and day 4, respectively. Thereafter, both serum and synovial fluid SAA decreased with eradication of joint infection, although they remained significantly increased from baseline until day 9 and day 10, respectively. Serum and synovial fluid SAA did not increase in the control or nonseptic synovitis group. These findings suggest that serial measurements rather than a single measurement of SAA are required to determine eradication of infection from septic arthritis in horses.

Brucella canis sacroiliitis and discospondylitis in a dog

A 1.5-year-old neutered male Labrador retriever dog was presented with a 1-month history of pelvic limb lameness. Physical examination revealed lumbosacral and pelvic pain. Diagnostic imaging findings were consistent with discospondylitis and bilateral sacroiliitis. Brucellosis was definitively diagnosed with rapid slide agglutination (RSAT) and agar gel immunodiffusion (AGID) tests. Brucella canis has not been associated with sacroiliitis and should be included as a differential diagnosis for dogs presented with clinical or radiographic signs of sacroiliitis.

Clinical findings and diagnostic test results for calves with septic arthritis: 64 cases (2009-2014)

OBJECTIVE To describe clinical findings and diagnostic test results and identify potential prognostic indicators for calves with septic arthritis. DESIGN Retrospective case series. ANIMALS 64 calves with septic arthritis. PROCEDURES The medical record database for a veterinary teaching hospital was searched to identify calves ≤ 6 months old that were treated for septic arthritis between 2009 and 2014. Data evaluated included signalment, history, physical examination and diagnostic test results, treatment, and outcome. Descriptive data were generated, and calves were assigned to 2 groups (neonatal [≤ 28 days old] or postneonatal [29 to 180 days old]) on the basis of age at hospital admission for comparison purposes. RESULTS 64 calves had 92 infected joints; 17 calves had polyarthritis. Carpal joints were most frequently affected followed by the stifle and tarsal joints. Forty-nine bacterial isolates were identified from synovial specimens for 38 calves, and the most commonly identified isolates were catalase-negative Streptococcus spp (n = 14) and Mycoplasma bovis (9). Calves in the neonatal group had a shorter interval between onset of clinical signs and hospitalization and were more likely to have an infected carpal joint than calves in the postneonatal group. Outcome was positive for 35 calves. Synovial fluid total nucleated cell count was positively associated with a positive outcome. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that empirical antimicrobial treatment for calves with septic arthritis should target gram-positive catalase-negative cocci and M bovis and that synovial fluid total nucleated cell count might be a useful prognostic indicator.

Modified abaxial approach for resection of the distal sesamoid bone and distal interphalangeal joint while preserving the digital flexor tendons of three Angus bulls with septic arthritis

CASE DESCRIPTION 3 Angus bulls, aged 2 to 3 years, with severe lameness of 2 to 4 weeks' duration and swelling proximal to the coronary band of the affected limb were evaluated after failing to respond to antimicrobial treatment. CLINICAL FINDINGS Septic arthritis of a distal interphalangeal joint (DIPJ) was diagnosed in all 3 bulls on the basis of results of a physical examination, radiographic and ultrasonographic evaluations of the affected foot, and cytologic evaluation of synovial fluid from the affected DIPJ. TREATMENT AND OUTCOME A novel modified abaxial approach was used to resect the infected distal sesamoid bone (navicular bone) and DIPJ of all 3 bulls. A window was created in the abaxial hoof wall that was lateral to and of sufficient size to extract the navicular bone. Following removal of the navicular bone, the DIPJ was debrided and resected and an orthopedic block was applied to the contralateral claw to minimize weight bearing on the infected digit. Two bulls also had a fiberglass cast applied to the affected limb to help immobilize the DIPJ. All 3 bulls recovered without complications, and 2 bulls were no longer lame, whereas the remaining bull was only mildly lame, at 4 to 5 weeks after surgery. CLINICAL RELEVANCE The modified abaxial approach described for surgical resection of the DIPJ allowed extraction of the infected navicular bone without damage to the digital flexor tendons, something that cannot be achieved with other abaxial approaches. This approach is best used for patients without septic tenosynovitis.

Use of standard diagnostic techniques to determine eradication of infection in experimental equine septic arthritis

Septic arthritis is an important disease in horses, necessitating aggressive and prolonged therapy. In order to guide therapy, reliable methods of detecting the eradication of infection are needed. Therefore, the objective of this study was to investigate detection of eradication of infection in an experimental model of equine septic arthritis using standard diagnostic techniques. For this purpose, 17 adult horses were assigned to 3 experimental groups. The middle carpal joint of each horse was injected with Escherichia coli (Septic group, n = 8), lipopolysaccharide (LPS) (LPS group, n = 6), or sterile saline (Control group, n = 3) at day 0. Contralateral joints were not injected. Standard therapy was applied to all joints except non-injected joints in the Control group at day 1. Sequential samples of synovial fluid (SF) were collected for bacterial culture using 3 culture media [Columbia blood agar (CBA), brain heart infusion broth (BHI), and Signal blood culture medium] and for cytological evaluation [percentage neutrophils (PN), total nucleated cell count (TNCC), and total protein (TP)]. Escherichia coli-specific polymerase chain reaction (PCR) was carried out to detect E. coli DNA in synovial fluid. Culture and PCR were positive for E. coli in all joints injected with E. coli at day 1 and 1 joint was positive on BHI at day 4. Based on the results of bacterial culture, PCR, and TNCC, the elimination of infection in our experimental model occurred by day 4 post-infection in 6 out of 7 cases. Total protein (TP) and PN remained elevated at clinical threshold used for diagnosis of septic arthritis until day 14. In our experimental model of E. coli-induced arthritis, we conclude that TP and PN may not be good indicators for detecting the eradication of bacterial infection caused by E. coli from infected and subsequently treated joints.

Phenotypic, genotypic and antigenic characterization of emerging avian reoviruses isolated from clinical cases of arthritis in broilers in Saskatchewan, Canada

In recent years, emerging strains of pathogenic arthrogenic avian reovirus (ARV) have become a challenge to the chicken industry across USA and Canada causing significant economic impact. In this study, we characterized emerging variant ARV strains and examined their genetic and antigenic relationship with reference strains. We isolated 37 emerging variant ARV strains from tendons of broiler chickens with clinical cases of arthritis/tenosynovitis at commercial farms in Saskatchewan, Canada. Viral characterization using immunocytochemistry, gold-immunolabeling and electron microscopy revealed distinct features characteristic of ARV. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the viral Sigma C gene revealed genetic heterogeneity between the field isolates. On phylogenetic analyses, the Sigma C amino acid sequences of the isolates were clustered into four distinct genotypic groups. These ARV field strains were genetically diverse and quite distant from the vaccine and vaccine related field strains. Antibodies produced against a commercial Reo 2177 ® vaccine did not neutralize these variants. Moreover, structure based analysis of the Sigma C protein revealed significant antigenic variability between the cluster groups and the vaccine strains. To the best of our knowledge, this is the first report on the genetic, phenotypic and antigenic characterization of emerging ARVs in Canada.

Naturally Occurring Mycoplasma Bovis—Associated Pneumonia and Polyarthritis in Feedlot Beef Calves

Mycoplasma bovis is perceived as an emerging cause of mortality in feedlot beef cattle. This study examined the lesions and infectious agents in naturally occurring M. bovis–associated bronchopneumonia and arthritis and the relationship of this condition with bovine viral diarrhea virus (BVDV) infection. Standardized pathologic, immunohistochemical, and microbiologic investigations were conducted on 99 calves that died or were euthanized within 60 days after arrival in 72 feedlots. Cranioventral bronchopneumonia with multiple foci of caseous necrosis was identified in 54 of 99 calves, including 30 with concurrent fibrinosuppurative bronchopneumonia typical of pneumonic pasteurellosis. Mycoplasma bovis was consistently identified in these lesions by culture and immunohistochemistry, but also commonly in healthy lungs and those with pneumonia of other causes. Focal lesions of coagulation necrosis, typical of pneumonic pasteurellosis, were often infected with both Mannheimia haemolytica and M. bovis. Arthritis was present in 25 of 54 (46%) calves with M. bovis pneumonia, and all calves with arthritis had pneumonia. BVDV infection was more common in calves with lesions of bacterial pneumonia than in those dying of other causes, but BVDV infection was not more common in calves with caseonecrotic bronchopneumonia than those with fibrinosuppurative bronchopneumonia. Retrospective analysis identified cases of M. bovis pneumonia in the early 1980s that had milder lesions than the current cases. The findings suggest that, in at least some calves, M. bovis induces caseonecrotic bronchopneumonia within the lesions of pneumonic pasteurellosis.

Fracture, Luxation, and Chronic Septic Arthritis of the Temporomandibular Joint in a Juvenile Horse

This case report describes chronic sepsis of the right temporomandibular joint in a juvenile horse. Diagnostic work-up included physical examination, radiography, and computed tomography. Humane euthanasia was indicated due to the chronicity of the condition, prognosis, and financial constraints.

Complete ostectomy of middle phalanx and partial ostectomy of proximal phalanx in a Brown Swiss calf for treatment of purulent arthritis of the proximal interphalangeal joint and adjacent severe osteomyelitis

A five month old Brown Swiss heifer calf (212 kg body mass) with severe left hind limb lameness, caused by a wound of the lateral digit was referred to the veterinary teaching hospital. The calf showed a score 4 of 5 lameness on the left hind limb. A scarified skin lesion with a fistula formation and purulent exudate was observed at the level of the proximal interphalangeal joint (PIJ) of the lateral digit of the left hind. The PIJ region and the lateral digit were severely swollen and painful. Ultrasonography showed a moderate anechoic effusion of the lateral digital flexor tendon sheet (DFTS) and a severe heterogeneous hypoechoic effusion with some small hyperechoic areas of the plantar and dorsal pouch of the PIJ. In addition, a highly irregular contour of the dorsal and abaxial surface of the phalanx media (P2) and the distal aspect of the proximal phalanx (P1) were imaged. Based on physical examination and ultrasonographic findings, the diagnosis was chronic purulent arthritis of the PIJ, osteitis of P2 and the distal end of P1 with suspected adjacent osteomyelitis. Complete ostectomy of P2 and ostectomy of the distal part of the P1 of the lateral digit was performed with an oscillating saw through the extended debrided wound. The lameness improved subsequently and 21 days post-surgery the calf was discharged from the clinic without lameness, and with a wooden block attached to the healthy claw. A year later the heifer was pregnant and still in the herd, during this period it did not exhibit lameness. The described surgical technique resulted in an excellent long-term outcome and may be considered in cases of severe purulent joint infection of the PIJ with osteolytic processes in adjacent bones, as a digit salvage procedure especially for young cattle.

Vertebral Osteomyelitis and Septic Arthritis Associated With Staphylococcus hyicus in a Juvenile Peregrine Falcon ( Falco peregrinus )

A 6-week-old, parent-reared peregrine falcon ( Falco peregrinus ) was presented with spastic hypertonus of its hind limbs of unknown origin and duration. Radiologic examination revealed smooth periosteal reactions ventrally at thoracic vertebrae 5 to 7. Contrast-enhanced computed tomography identified the swelling as inflammation; antibiotic, antimycotic, anti-inflammatory, and analgesic treatments were initiated, and vitamins and minerals were supplemented. Because the bird's condition did not improve after 10 days, it was euthanatized and submitted for postmortem examination. On histopathologic examination, chronic, active osteomyelitis was diagnosed in thoracic vertebrae 5 to 7, and chronic, active arthritis was present in both the right shoulder and left elbow joints. Staphylococcus hyicus was isolated from these 3 locations, as well as from lungs and liver, indicating a chronic septic staphylococcosis. Although infections with Staphylococcus species are occasional causes of vertebral osteomyelitis in juvenile poultry with active growth plates, it is only sporadically reported in raptors and companion birds. This case report is the first description of the clinical features and diagnostic and pathologic findings in a juvenile peregrine falcon with hematogenous osteomyelitis and arthritis associated with septicemia caused by S hyicus.

Bilateral renal dysplasia, hydronephrosis, and hydroureter in a septic neonatal foal

A Canadian warmblood foal treated for septic polyarthritis was diagnosed with bilateral congenital renal dysplasia, hydronephrosis, and hydroureter at 2 weeks of age based on abdominal ultrasound and postmortem examination. Intermittent abdominal pain throughout the course of treatment was attributed to hydronephrosis and hydroureter.

[Resection of a carpal bone row in a Pustertaler Sprinze cow with chronic purulent arthritis of the carpal joint and osteomyelitis]

This case report describes the clinical and radiographic findings and the surgical treatment of a serofibrinous arthritis of the antebrachiocarpal joint and of a chronic purulent arthritis of the intercarpal and carpometacarpal joints with osteomyelitis of the distal carpal bones and subchondral osteomyelitis of the proximal metacarpal bones in a cow of the breed "Pustertaler Sprinze". The therapy comprised an arthrotomy of both joint spaces and the resection of the distal row of the carpal bones. The right forelimb had been immobilised for 70 days by a full limb cast. After this period, radiographs revealed an ob- vious ankylosis of the carpal joint, and the cow showed only a slight lameness. Six years postoperatively this cow was still in the herd and had produced six calves.

Otitis interna, media, and externa with destruction of the left tympanic bulla and subluxation and septic arthritis of the left temporomandibular joint in an alpaca (Vicugna pacos)

A 1.5-year-old, 37.7 kg, female alpaca was evaluated for a 2-week history of weight loss, left ear droop, and deviation of the rostral mandible to the right. Antemortem radiography and postmortem examination revealed otitis interna, media, and externa, destruction of the left tympanic bulla, and subluxation and septic arthritis of the left temporomandibular joint.

Carpal intra-articular blastomycosis in a Labrador retriever

A 6-month-old male castrated Labrador retriever was presented for coughing and forelimb lameness. Blastomyces dermatitidis was identified in cytology of sputum and synovial fluid. Repeat arthrocentesis 7 months later revealed resolution of septic arthritis. Fungal septic arthritis should be considered for cases of monoarthritis and may respond to oral itraconazole treatment.

Candida osteomyelitis in a gelding

A 2-year-old gelding was referred for evaluation of severe right forelimb lameness. The horse was grade 4/5 lame on the right forelimb. Clinical, laboratory, and radiographic findings were consistent with septic arthritis and osteomyelitis. Due to poor prognosis the owner elected euthanasia. Histopathology confirmed chronic arthritis and osteomyelitis with intralesional yeast (Candida species).

Clinical investigation of local implantation of gentamicin-impregnated collagen sponges in dogs

The purpose of this study was to evaluate the effects on health and kidney function of local implantation of commercial gentamicin-impregnated collagen sponges. Four healthy dogs were submitted to local surgical implantation of collagen impregnated sponges. Follow-up with serial physical examinations and measurements of serum creatinine, urea nitrogen, and gentamicin were performed for 7 d. There were no adverse reactions, or changes in measurements of kidney function.

What is the likelihood that Thoroughbred foals treated for septic arthritis will race?

REASONS FOR PERFORMING STUDY

Septic arthritis is a serious problem in the neonate, with a poor prognosis being reported for recovery. The impact of neonatal septic arthritis on the likelihood that Thoroughbred (TB) foals will start on a racecourse is not known.

HYPOTHESIS

The development of septic arthritis in a TB foal significantly reduces the likelihood that it will race when compared to foals from the same dam.

METHODS

Medical records of 69 foals treated for septic arthritis were reviewed. The dam's foaling records were reviewed and lifetime racing records were then retrieved for both the affected foals and at least one of their siblings (controls). Outcomes that were statistically evaluated included discharge from the hospital and whether the foal eventually raced. Univariate analyses of categorical variables were conducted for each outcome. The number of affected and unaffected foals that raced at least once were compared using regression analysis. Survival analysis was used to compare age at first race between the study and comparison groups.

RESULTS

Foals with septic arthritis were less likely to start on a racecourse compared to controls (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.12-0.62, P = 0.001), while those foals that were discharged from the hospital were also less likely to start on a racecourse compared to controls (OR 036; CI 0.15-0.83, P = 0.008). The presence of multisystem disease was associated with a decreased likelihood of surviving to be discharged (OR 0.13; 95% CI 0.02-0.90; P = 0.005), but did not affect the likelihood that they would start in at least one race if discharged successfully (OR 0.45; 95% CI 0.04-2.81; P = 0.34) compared to the other foals with septic arthritis. Log-rank comparison of survival curves confirmed that foals discharged following treatment for septic arthritis took significantly longer to start in their first race compared to the sibling population (mean age of study group 1757 days, CI 1604-1909; mean age of sibling group 1273 days, CI 1197-1349; P = 0.0006).

CONCLUSIONS

The development of septic arthritis in a TB foal significantly reduces the likelihood that it will start on a racecourse when compared to controls.

POTENTIAL RELEVANCE

Accurate figures allowing a realistic assessment of the athletic future of a foal following treatment for septic arthritis are of significance for both owner and treating veterinarian.

Septic arthritis in adult horses

Septic arthritis in horses is a serious disease which can become life-threatening. In case the infection can be eliminated before irreversible joint damage occurs, complete recovery is possible. This article gives an overview of the literature concerning etiology, diagnosis and strategies of therapy in cases of septic arthritis in adult horses, with special reference to novel options of treatment.

Isolation of Mycoplasma hyosynoviae from pneumonic lung of swine

The isolation of Mycoplasma hyosynoviae from a piglet with severe pneumonia is described. This is the first report of M. hyosynoviae isolation in the country. The lung sample where the isolation was made was severely consolidated, suppurative and pleurisy. The pathogenicity of the M. hyosynoviae isolated has yet to be determined.

Measurement of equine myeloperoxidase (MPO) activity in synovial fluid by a modified MPO assay and evaluation of joint diseases – An initial case study

The aim of this study was to develop a specific myeloperoxidase (MPO) activity assay in the synovial fluid of horses and investigate whether MPO activity is increased in different forms of joint diseases. Synovial fluid samples were taken from affected joints from horses with osteoarthritis, chronic non-septic arthritis and septic arthritis, and from healthy control horses. MPO activity was measured using a specific modified o-dianisidine-assay containing 4-aminobenzoic acid hydrazide as a potent and specific inhibitor of the MPO. This assay is characterized by high reproducibility. The results reveal only a slight elevation of MPO activity in the synovial fluid of horses with osteoarthritis and chronic non-septic arthritis. However, in the cases of septic arthritis a significant increase in MPO activity was found when compared to the controls. In conclusion the first field study suggests that synovial fluid MPO may be used as a marker for septic arthritis in horses.

Intraarticular Dirofilaria immitis microfilariae in two dogs

Dirofilaria immitis microfilariae were found in the synovial fluid of two dogs. One dog had clinical and cytological evidence of polyarthritis at the time of presentation. The second dog presented with severe effusion in a single joint and was later diagnosed with synovial sarcoma of the affected joint. These patients were not protected with heartworm prophylaxis and lived in heartworm endemic areas. Though there is documentation of D. immitis microfilaria in the synovial fluid of several clinically normal research dogs with cytologically normal synovial fluid, to our knowledge these are the first documented cases of intraarticular microfilaria in a dog with cytologically confirmed polyarthritis. Based on these unique cases, D. immitis infection should be considered a differential diagnosis in patients with polyarthropathies. Interpretive caution must be used when intraarticular microfilaria are present, as concurrent etiologies may also be present.

Facilitated ankylosis of the distal interphalangeal joint in a foal

A 3-month-old Quarter Horse colt sustained a penetrating injury over the coronary band on the right forelimb resulting in an articular bone sequestrum and septic arthritis of the distal interphalangeal joint. Despite aggressive treatment for septic arthritis, severe osteoarthritis and ongoing sepsis resulted in persistent lameness. Facilitated ankylosis of the distal interphalangeal joint was performed using a combination of open surgical debridement, placement of an autogenous cancellous bone graft and stabilisation within a transfixation cast. Bony ankylosis of the joint was observed radiographically 7 weeks following surgery. Evaluation of the horse 30 months following surgery revealed complete fusion of the middle and distal phalanges, and the distal sesamoid bone. The horse is pasture sound and is used as a breeding stallion. This report describes the surgical approach and case management employed to achieve facilitated ankylosis as a treatment for unresolved septic arthritis of the distal interphalangeal joint. This is the first report of successful facilitated ankylosis of the distal interphalangeal joint in a foal.

Streptococcus ictaluri arthritis, osteolysis, myositis, and spinal meningitis in channel catfish broodstock

This report details findings of an investigation into complaints by commercial fingerling producers of low-grade mortalities, poor reproductive success, emaciation, skin lesions, and severely arched backs among broodstock of channel catfish Ictalurus punctatus. Gross lesions involved the jaw, fin bases, and vertebral column. Jaw and fin lesions consisted of small hemorrhagic ulcers and exudate-filled tracts that communicated with underlying joints and destroyed their articular surfaces. Spinal changes, recognized grossly by severe arching of the proximal vertebral column, resulted from the collapse and displacement of vertebral bodies, causing compression of the spinal cord. Affected vertebrae were lysed by pyogranulomatous inflammation that infiltrated into adjacent muscle and the spinal canal. A Streptococcus-like organism was visualized in exudate and isolated repeatedly from lesions, but only once from the kidney of a single fish. Preliminary analysis of a 16S ribosomal DNA sequence showed a close relationship to S. iniae, S. parauberis, and S. canis. Koch's postulates were fulfilled after challenge with and reisolation of the agent from identical lesions that appeared at fin bases at 2 weeks postinjection. Historical evidence and gross and microscopic findings imply the presence of a pathogen of low virulence that is capable of producing severe localized infections after a brief period of septicemia. The disease presents as a chronic debilitating syndrome that is sufficient to inhibit mobility, feeding, and reproductive activity in affected fish. Complete biochemical and molecular characterization of the bacterium (published elsewhere) has established the agent as a novel species, S. ictaluri.

Bacterial infective arthritis of the coxofemoral joint in dogs with hip dysplasia

The objective of this study was to describe seven cases of unilateral bacterial infective coxarthritis from a total of 19 cases of bacterial infective arthritis (BIA), presenting over a two year period. We recorded the history, clinical signs, diagnostic process, treatment and clinical outcome in these cases. The data were obtained from medical records, review of the radiographs, and telephone follow-up with the owners. All of the dogs in this study had severe chronic osteoarthritis secondary to hip dysplasia, which caused periodic hind limb lameness. They were all admitted with severe acute hind-limb lameness. Pelvic radiographs were performed under general anaesthesia shortly after presentation, followed immediately by arthrocentesis of the affected joint. The synovial fluid was evaluated microscopically by direct smear and a sample was sent for culture and sensitivity. An attempt was not made to drain or lavage the affected joint during the course of treatment. The initial choice of antibiotics was empiric and subsequently modified, as required, based on the sensitivity results. Four of the dogs showed a rapid return to weight-bearing after the initiation of antibiotic treatment, and all of the patients returned to their pre-BIA level of function. Neither recurrent infections nor any adverse sequela requiring further intervention were reported by the owners on telephone follow-up.

Use of matrix metalloproteinases 2 and 9 and white blood cell counts in monitoring the treatment and predicting the survival of horses with septic arthritis

Thirty-nine samples of synovial fluid were collected from the joints of 32 horses with suspected septic arthritis and 39 samples were collected from horses euthanased for non-orthopaedic conditions. The white blood cell counts (WBCC) were determined and the pro and active forms of matrix metalloproteinases (MMPs) 2 and 9 were measured by gelatin zymography and image analysis in each sample. The initial measurements of the ratio of proMMP9:proMMp2 and WBCC were good prognostic indicators of the survival of the horses. There was no significant relationship between the interval between the injury and the horse being referred for treatment and either the WBCC or the levels of MMP2 and MMP9 initially, and no evidence that this interval significantly affected the chances of the horses surviving.

Imaging diagnosis--discospondylitis and septic arthritis in a dog

A 6-year-old German Shepherd dog was evaluated for hind limb lameness. When a diagnosis, could not be achieved using radiography and ultrasonography, bone scintigraphy was performed to look for occult lameness or the presence of multiostic disease. Bone scintigraphy was useful in identification of increased radiopharmaceutical uptake in the thoracic spine and right coxofemoral joint, which directed further testing leading to the diagnosis of discospondylitis, septic arthritis of the coxofemoral joint, and a urinary tract infection.

Septic Arthritis of the Distal Interphalangeal Joint in Cattle: Comparison of Digital Amputation and Joint Resection by Solar Approach

OBJECTIVE

To determine in cattle with septic arthritis of the distal interphalangeal joint (SADIJ) the efficacy of resection of the distal interphalangeal joint (JRES) as a digit salvage technique compared with digital amputation (DAMP).

STUDY DESIGN

Prospective, randomized clinical study.

ANIMALS

German Holstein-Friesian dairy cattle with SADIJ of 1 hind limb (n=52).

METHODS

SADIJ diagnosis was based on clinical examination and radiography. Cows were randomly assigned with owner consent to DAMP (n=26) or JRES (n=26). After JRES, a wooden block was fixed to the partner claw in combination with a tipping claw prophylaxis.

RESULTS

After surgery, degree of lameness improved significantly faster after DAMP than after JRES. New claw diseases in the opposite limb occurred more frequently after JRES (n=6) than after DAMP (n=1). New claw defects developed in the partner claw on the operated limb in 6 cows after DAMP compared with 1 after JRES. Tipping claw was observed in 50% of JRES cows at day 180. Mean life span between groups was not significantly different (DAMP=13.5 months, JRES=10.9 months).

CONCLUSION

Higher surgical and postsurgical expenditures for JRES were not counterbalanced by a longer productive life; however, frequent disease of the partner claw of cows after DAMP should be considered a critical point, as this generally leads to culling.

CLINICAL RELEVANCE

The higher expenditure for JRES can be justified only for young, valuable cattle.

Spondylitis in a humpback whale (Megaptera novaeangliae) from the southeast Pacific

A 7.25 m long male humpback whale (Megaptera novaeangliae) with spondylitis was found beached on August 13, 1994 at Ancon, Ecuador (2 degrees 23' S, 80 degrees 47' W). The condition involved at least 11 vertebrae, 7 lumbar (L4 to L11) and 4 caudal (Ca1 to Ca4). Partial fusion of vertebrae was observed as a result of intervertebral bony proliferation, likely impeding full motion. The relatively young age of this specimen and the severity of the deformities suggest an infectious, rather than degenerative, process. The gross findings are most consistent with some type of spondyloarthritis. Although this condition has previously been identified in a number of cetacean species, the pathogenesis, population impact and ecologic implications have not been fully assessed. This is the third case described for humpback whales and the first for a humpback whale from the SE Pacific.

Unusual history and initial clinical signs ofMycoplasma bovismastitis and arthritis in first-lactation cows in a closed commercial dairy herd

CASE DESCRIPTION

9 first-lactation dairy cows in a closed dairy herd had swelling in the forelimbs and forelimb lameness. Mycoplasmal arthritis and mastitis were diagnosed.

CLINICAL FINDINGS

Swelling of the carpal joint, diffuse subcutaneous edema from the carpal to metacarpophalangeal joints, and forelimb lameness were evident in 9 first-lactation cows 7 to 21 days after parturition. Diagnostic testing revealed that 3 of 3 bulk-tank milk samples, 3 milk samples from cows with clinical mastitis, 2 fluid samples obtained from arthritic joints, and samples from the lungs and spleen of a cow that had died yielded positive results for Mycoplasma spp. Nucleic acid sequence analysis performed by use of a PCR assay on the joint fluid and lung tissues confirmed infection with Mycoplasma bovis.

TREATMENT AND OUTCOME

Affected cows were treated by IM administration of flunixin meglumine and dexamethasone for 3 days. All cows were nonresponsive to treatment (3 cows died, and the other 6 were culled). Follow-up culture for Mycoplasma spp of milk samples from the bulk tank and from all lactating cows was recommended to screen for chronic subclinical carriers.

CLINICAL RELEVANCE

Mycoplasmal infections may cause unusual initial clinical signs or an atypical history. When dairy cattle, including those residing in closed herds, have lameness, swelling of the carpal or metacarpophalangeal joints, edema of the distal portions of the forelimbs, or polyarthritis, infection with Mycoplasma spp should be investigated. Delay in diagnosis of mycoplasmal infections in dairy herds can result in substantial financial loss and the establishment of chronic subclinical carriers.

Field technique for the resection of the distal interphalangeal joint and proximal resection of the deep digital flexor tendon in cows

A modified technique for the resection of the distal interphalangeal joint and the proximal resection of the deep digital flexor tendon in cows is described. Septic arthritis of the joint was diagnosed in eight Holstein cows and treated in the field. Four of the cows were diagnosed with ascending tendonitis during the resection of the joint and their tendons were also resected. All the animals remained moderately to severely lame for two weeks postoperatively but quickly recovered and were sound within five months. Eight months after the last surgery only one cow had been culled, 321 days after its surgery, for reproductive failure. The other seven cows had survived for a mean period of 308 days, with a range from 235 to 392 days.

Ultrasound-guided coxofemoral arthrocentesis in horses

REASON FOR PERFORMING STUDY

Coxofemoral joint pain is probably underestimated due to difficulties in identifying hip pain. The deep location of the joint and proximity of the sciatic nerve make arthrocentesis based on external landmarks a difficult and potentially risky procedure in mature horses.

OBJECTIVES

To describe an ultrasound-guided injection technique of the coxofemoral joint in standing horses and to evaluate its accuracy and potential difficulties/complications.

METHODS

Nine mature horses had both pelvic areas prepared for sterile ultrasound examination (3.5 MHz curvilinear probe). Coxofemoral joints were located and penetrated at their craniodorsolateral aspect under ultrasonographic guidance and injected with sterile contrast medium. A standing ventrodorsal radiographic view of each hemipelvis centred on the hip was obtained for each horse to assess the injection site. Horses were evaluated for 10 days following injection for possible complications.

RESULTS

Intra-articular injection was successful in all 18 joints. The procedure was well tolerated by horses under minimal restraint. Mean +/- s.d. needle repositionings required before accurate placement was 1.5 +/- 1.3 per joint. Once the needle was in the joint, synovial fluid was obtained in 7/18 joints. Minimal periarticular contrast medium was detected in 2/18 joints. Mean +/- s.d. ultrasonographic examination time required for coxofemoral localisation, accurate needle positioning and injection was 4.3 +/- 2.1 min. No complications were observed in the 10 days following injection.

CONCLUSION

The ultrasound-guided coxofemoral arthrocentesis is an accurate, reliable and safe technique that offers a real time evaluation of needle introduction into the deep and narrow coxofemoral joint space.

POTENTIAL RELEVANCE

Although this technique remains to be tested on clinical cases, it is a promising tool to facilitate diagnosis of coxofemoral pain, septic arthritis or administration of intra-articular medication.

Detection of DNA from a range of bacterial species in the knee joints of dogs with inflammatory knee arthritis and associated degenerative anterior cruciate ligament rupture

Mixtures of bacterial nucleic acids can often be detected in synovial joints affected with arthritis. We investigated the potential role of such mixtures of bacterial nucleic acids in the pathogenesis of arthritis in a naturally occurring canine model. Dogs with a common inflammatory knee arthritis in which associated pathological degenerative anterior cruciate ligament (ACL) rupture often develops were studied. Synovial biopsies were obtained from 43 dogs with the naturally occurring ACL rupture arthropathy, 12 dogs with normal knees and intact ACL, and 16 dogs with normal knees and experimentally induced ACL rupture. Using PCR, specimens were tested for Borrelia burgdorferi OspA and p66 gene sequences. Broad-ranging 16S rRNA primers were also used; 'panbacterial' PCR products were cloned and multiple clones were sequenced for bacterial identification. Synovium was also studied histologically. The presence of bacterial DNA within the synovium was significantly associated with the naturally occurring ACL rupture arthropathy (p<0.05); knee joints from 37% of these dogs were PCR-positive. Mixtures of bacterial DNA were common and often included environmental bacteria; predominant organisms included Borrelia burgdorferi and Stenotrophomonas maltophilia. DNA from environmental bacteria was only found in dogs with the naturally occurring ACL rupture arthopathy; joints from 33% of affected dogs contained such bacterial DNA. Synovial inflammation developed in dogs with both naturally occurring and experimentally induced ACL rupture, when compared with intact ACL controls (p<0.01). These results indicate that mixtures of DNA derived from environmental bacteria are commonly found in the knee joint of a naturally occurring canine arthropathy, often in association with a recognized joint pathogen. Our results also suggest that knee instability alone is not responsible for this finding and have led us to hypothesize that mixtures of bacterial DNA are an important causative factor in the pathogenesis of inflammatory arthritis in this canine model.

Evaluation of the rate of development of septic arthritis after elective arthroscopy in horses: 7 cases (1994–2003)

OBJECTIVE

To determine the rate of development of septic arthritis after elective arthroscopy and evaluate associations between various factors and development of this complication in horses.

DESIGN

Retrospective case series.

ANIMALS

682 horses that underwent arthroscopic procedures at the University of Illinois Veterinary Teaching Hospital from 1994 to 2003.

PROCEDURES

Information pertaining to signalment, joints treated, whether antimicrobials were administered, and development of postoperative septic arthritis was collected from medical records. Horses with a primary problem of septic arthritis or wounds involving joints were excluded. The following factors were evaluated to determine their roles in joint sepsis: breed, sex, joint, and preoperative and intra-articular administration of antimicrobials. Telephone interviews with clients were used to determine whether unreported septic arthritis had developed.

RESULTS

8 of 932 (0.9%) joints in 7 of 682 (1.0%) horses that underwent arthroscopy developed postoperative septic arthritis. Follow-up information after discharge from the hospital was available for 461 of the 682 horses, and of those, 8 of 627 (1.3%) joints in 7 of 461 (1.5%) horses developed septic arthritis. Breed and joint treated were significant risk factors for development of postoperative septic arthritis, with draft breeds and tibiotarsal joints more likely than others to be affected. Sex, preoperatively administered antimicrobials, and intra-articularly administered antimicrobials were not associated with development of postoperative septic arthritis.

CONCLUSIONS AND CLINICAL RELEVANCE

Results can be used for comparison with data from other institutions and surgical facilities. Additional precautions should be undertaken when arthroscopic surgery involves draft breeds and tibiotarsal joints.

Concentrations of serum amyloid A in serum and synovial fluid from healthy horses and horses with joint disease

OBJECTIVE

To determine serum amyloid A (SAA) concentrations in serum and synovial fluid from healthy horses and horses with joint disease and assess the effect of repeated arthrocentesis on SAA concentrations in synovial fluid. Animals-10 healthy horses and 21 horses with various types of joint disease.

PROCEDURES

Serum and synovial fluid samples were obtained from each horse. In 5 of the 10 healthy horses, arthrocentesis was repeated 9 times. Concentrations of SAA were determined via immunoturbidometry.

RESULTS

Serum and synovial fluid SAA concentrations were less than the assay detection limit in healthy horses and did not change in response to repeated arthrocentesis. Synovial fluid SAA concentrations were significantly higher in horses with suspected bacterial joint contamination or infectious arthritis, or tenovaginitis than in healthy controls, and serum concentrations were significantly higher in horses with infectious conditions than in the other groups. Neither serum nor synovial fluid SAA concentrations in horses with low-inflammation joint conditions differed significantly from those in healthy controls. Concentrations of SAA and total protein in synovial fluid were significantly correlated.

CONCLUSIONS AND CLINICAL RELEVANCE

Synovial fluid SAA concentration was a good marker of infectious arthritis and tenovaginitis and appeared to reflect changes in inflammatory activity. The advantages of use of SAA as a marker include the ease and speed of measurement and the fact that concentrations in synovial fluid were not influenced by repeated arthrocentesis in healthy horses. Further study of the SAA response in osteoarthritic joints to assess its usefulness in diagnosis and monitoring of osteoarthritis is warranted.

Mandibular Condylectomy and Meniscectomy for the Treatment of Septic Temporomandibular Joint Arthritis in a Horse

OBJECTIVE

To report use of mandibular condylectomy for treatment of advanced degenerative joint disease of the temporomandibular joint (TMJ) caused by sepsis.

DESIGN

Clinical case report.

ANIMALS

Two-year-old Noriker filly.

METHODS

Computed tomography (CT) was used to confirm advanced degenerative joint disease of the left TMJ and for follow-up after mandibular condylectomy and removal of necrotic meniscus.

RESULTS

Painful swelling (3 weeks duration) with drainage located just caudal to the left lateral canthus of the eye was associated with atrophy of the left masseter muscle, masticatory problems, and inappetence. There was incisor malocclusion with a 1.4 cm resting lateral mandibular deviation to the right and inability to open the mouth more than a few centimeters. Left mandibular condylectomy combined with meniscectomy and thorough debridement of the septic left TMJ resulted in resolution of clinical signs and complete return of function. Streptococcus zooepidemicus, intermediately resistant to penicillin and subsequently to enrofloxacin, was isolated from the wound. Regeneration of a mandibular "pseudocondyle" was evident on CT at 4 months. At 4 months and 1 year the filly had maximal mouth opening >10 cm and no malocclusion.

CONCLUSION

Mandibular condylectomy can be used to facilitate management of septic TMJ arthritis. There was no radiologic or clinical evidence of TMJ ankylosis >1 year after meniscal removal.

CLINICAL RELEVANCE

Mandibular condylectomy, including meniscectomy, is an acceptable treatment option for advanced TMJ septic arthritis and allowed return of normal masticatory function.

Mycoplasma felis arthritis in two cats

This report describes the occurrence of non-weightbearing lameness caused by Mycoplasma felis monoarthritis in two, immunocompetent, European, shorthair adult cats with a suspected history of trauma. Clinical signs recurred after conservative treatment. The joints were treated surgically and M felis was identified as the causative agent for the monoarthritis. Medication with 10 mg/kg doxycycline twice daily was initiated according to susceptibility testing. One cat underwent further joint flushing after two weeks; both the cats recovered completely after eight and nine weeks, respectively. The findings suggest that M felis, in addition to being an agent associated with conjunctivitis in cats, is able to act as a pathogen in other tissues and cause arthritis even in immunocompetent cats.

Gentamicin concentrations in synovial fluid obtained from the tarsocrural joints of horses after implantation of gentamicin-impregnated collagen sponges

OBJECTIVE

To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge.

ANIMALS

6 healthy adult mares.

PROCEDURES

A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of a fluorescence polarization immunoassay. Synovial membrane and cartilage specimens were collected 120 hours after implantation and evaluated histologically.

RESULTS

Median peak synovial fluid gentamicin concentration of 168.9 microg/mL (range, 115.6 to 332 microg/mL) was achieved 3 hours after implantation. Synovial fluid gentamicin concentrations were < 4 microg/mL by 48 hours. Major histologic differences were not observed in the synovial membrane between control joints and joints implanted with gentamicin-impregnated sponges. Safranin-O fast green stain was not reduced in cartilage specimens obtained from treated joints, compared with those from control joints.

CONCLUSIONS AND CLINICAL RELEVANCE

Implantation of a gentamicin-impregnated collagen sponge in the tarsocrural joint of horses resulted in rapid release of gentamicin, with peak concentrations > 20 times the minimum inhibitory concentration reported for common pathogens that infect horses. A rapid decrease in synovial fluid gentamicin concentrations was detected. The purified bovine type I collagen sponges did not elicit substantial inflammation in the synovial membrane or cause mechanical trauma to the articular cartilage.

Differential expression of U2AF35 in the arthritic joint of avian reovirus-infected chicks

To identify cell types and genes that are differentially expressed during immunopathogenesis of avian reovirus (ARV)-induced viral arthritis (VA), we inoculated arthrotropic strain S1133 of ARV into 1-day-old broilers, and examined tissue histology as well as RNA expression at different days post-inoculation (PI). Using immunohistochemical staining, we detected many CD68 expressing macrophages in and around the blood vessels of the arthritic joints. By RT-PCR, we found that expression of matrix metalloproteinase-2 (MMP-2) and bone morphogenetic protein-2 (BMP-2) was induced earlier in footpads and hock joints of ARV-infected chickens. By employing suppression subtractive hybridization (SSH) technique and RT-PCR, we further identified that small subunit of U2 snRNP auxiliary factor (U2AF35 or U2AF1) mRNA was differentially induced in the joint of ARV-infected chickens. By in situ hybridization (ISH), mRNA signals of U2AF35 and BMP-2 were located in chondrocytes within/near the epiphyseal plate and secondary center of ossification, and in epidermal cells and dermal fibroblast-like cells of arthritic joints. In addition, U2AF35 mRNA was expressed in the inflammatory infiltrates of the bone marrow of ARV-infected arthritic joints, while MMP-2 was mainly detected in chondrocytes. Interestingly, among U2AF35, MMP-2, and BMP-2 that were differentially expressed in the joint of ARV-infected chickens, only U2AF35 induction correlated well with arthritic manifestation. Because U2AF35 may assist in mRNA splicing of proinflammatory chemokines and cytokines, our results indicated that U2AF35 induction might play an immunopathological role in ARV-induced arthritis. This study has first associated U2AF35 to viral arthritis.

Septic Arthritis, Tenosynovitis, and Infections of Hoof Structures

Infectious diseases of synovial and hoof structures in horses can be devastating to soundness and can result in life-threatening complications. Timely diagnosis and early aggressive treatment can result in successful outcomes and resumption of athletic careers; however, delays in recognition and therapy can be the most costly reasons for failure. Sterilization of affected compartments and tissues requires removal of microorganisms and compromised tissue. Debridement, lavage, and appropriate antimicrobial drug use are the most reliable avenues of treatment. Antimicrobial drugs can be administered by local, regional, and systemic routes. Lavage techniques and debridement typically require surgical manipulations.