The presence of antiphospholipid antibodies in healthy Bernese Mountain Dogs

Background

The role of antiphospholipid antibodies in the prolonged activated partial thromboplastin time (aPTT) previously identified in healthy Bernese Mountain Dogs remains unknown. In people, an isolated prolonged aPTT without evidence of bleeding might be because of a thrombophilic condition caused by antiphospholipid antibodies.

Objective

To examine if prolonged aPTT in healthy Bernese Mountain Dogs is because of antiphospholipid antibodies.

Animals

Twenty‐two healthy Bernese Mountain Dogs and 10 healthy adult dogs of various breeds.

Methods

Prospective case control study. Healthy Bernese Moutain Dogs were examined twice over 6 months. Dogs were investigated for the presence of lupus anticoagulants and anticardiolipin (aCL) antibodies by the use of multiple aPTT tests with low and high lupus anticoagulant sensitivities, a mixing study, and an ELISA test for aCL antibody optical density to detect solid phase antiphospholipid antibodies.

Results

In all, 15 of 22 healthy Bernese Mountain Dogs were positive for lupus anticoagulants. The Bernese Mountain Dogs had markedly higher levels of aCL antibodies compared with the control dogs (P = .006). In all, 7 of 21 of the Bernese Mountain Dogs were positive for both lupus anticoagulants and aCL antibodies, whereas 4 of 21 Bernese Mountain Dogs were negative for both.

Conclusions and Clinical Importance

Lupus anticoagulants and aCL antibodies could be the cause of prolonged aPTT in healthy Bernese Mountain Dogs. The importance of the antiphospholipid antibodies in the dogs remains unknown.     

Seroprevalence against Borrelia burgdorferi sensu lato and occurence of antibody co-expression with Anaplasma phagocytophilum in dogs in Latvia

Background

Lyme disease is commonly diagnosed in humans in Latvia, but up to date no studies have been performed to investigate its prevalence in dogs. The aim of this study was to evaluate if seroprevalence against B. burgdorferi sensu lato (B. burgdorferi s.l.) and co-expression of antibodies against B.burgdorferi s.l. and A. phagocytophilum is higher in dogs with clinical suspicion of tick-borne diseases compared to healthy dogs.

Findings

Venous blood was taken from healthy dogs (n=441) and dogs suspected to have borreliosis and/ or canine granulocytic anaplasmosis (n=29). The presence of antibodies was detected with SNAP 4Dx test (IDEXX, Westbrook, Maine, USA). The seroprevalence against B. burgdorferi s.l. in healthy dogs was 2.49% (11/441) and 36% (4/11) of seropositive dogs had antibodies against both of investigated bacteria. None of the dogs in sick dog group had detectable antibodies against B. burgdorferi s.l.

Conclusions

We conclude that seroprevalence to B. burgdorferi s.l. in dogs in Latvia is low and that dogs with suspicion of tick-borne disease do not have higher B. burgdorferi s.l. seroprevalence than healthy dogs. Dogs that express antibodies against B. burgdorferi s.l. frequently co-express antibodies against A. phagocytophilum.     

Serodiagnosis of Lyme disease in UK dogs

Lyme disease is a chronic, multisystemic, inflammatory disorder of man and animals associated with infection by the tick-borne spirochaete, Borrelia burgdorferi. Lyme disease was recently reported for the first time in a dog in the UK (May and others 1990). Using an enzyme-linked immunosorbent assay (ELISA), we have performed a serological survey to investigate the prevalence of antibodies to B burgdorferi in UK dogs. The survey has shown that dogs from many areas in the UK have serum antibodies to B burgdorferi, that the presence of serum antibodies is associated with known exposure to ticks and that some dogs seropositive for B burgdorferi have clinical signs consistent with Lyme disease. High levels of serum anti-Borrelia antibodies are not diagnostic for canine Lyme disease, but, in association with appropriate clinical signs, they help to confirm the diagnosis in suspected cases.     

Prevalence of antibodies against Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum and their clinical relevance in dogs in Munich, Germany

Although prevalences of antibodies against Borrelia (B.) burgdorferi sensu lato (sl) and Anaplasma (A.) phagocytophilum have been reported to be high in the German dog population, the importance of the diseases caused by both agents is still not well characterized in a field situation.The aim of this study was (1) to determine the prevalence of antibodies to B. burgdorferi sl and A. phagocytophilum in dogs in Munich, Germany, and (2) to assess the clinical presentation and laboratory values of antibody-positive dogs and compare them to a negative control group. In total, 448 randomly selected dogs were screened for antibodies to B. burgdorferi sl and A. phagocytophilum with the SNAP 4Dx assay (IDEXX, Laboratories, Inc., USA). Dogs carrying antibodies against B. burgdorferi sl and/or A. phagocytophilum were classified as "positive"(n=100), the following 100 negative dogs served as control group. In both groups, physical examination and laboratory parameters were compared. 22 (4.9%) dogs had antibodies to B. burgdorferi sl, 78 (19.4%) to A. phagocytophilum, nine (2.0%) to both agents. Bernese Mountain Dogs had significantly more often antibodies against B. burgdorferi sl. Negative dogs were more often diagnosed as "healthy" compared to A. phagocytophilum antibody-positives that showed more often elevated body temperature and poor general condition; beyond that, there were no differences in clinical and laboratory abnormalities between both groups. Although dogs tested negative were more often considered healthy, there were no differences in parameters considered "specific" for both infections between dogs with and without antibodies. Hence, tests detecting antibodies against both agents are not able to detect animals with the clinical disease.     

Association of urine protein excretion and infection with Borrelia burgdorferi sensu lato in Bernese Mountain dogs

Bernese Mountain dogs (BMDs) are prone to develop a familial glomerulonephropathy and a pathogenic role of Borrelia burgdorferi sensu lato in this disease has been suspected. Glomerular disease in many affected dogs is clinically inapparent and proteinuria is found incidentally. In this study, urine protein excretion was evaluated in 122 clinically healthy BMDs and 55 controls. The seroprevalence of B. burgdorferi in BMDs was 57%, compared to 16% in controls. There were no significant differences in the occurrence of positive dipstick results, microalbuminuria, urine protein-to-urine creatinine ratio or abnormal urine protein pattern (determined by sodium dodecyl sulphate agarose gel electrophoresis) between BMDs and controls and BMDs with and without antibodies against B. burgdorferi. It was concluded that antibodies against B. burgdorferi are not associated with proteinuria as an early sign of renal disease in BMDs.     

Ability of an oral formulation of afoxolaner to protect dogs from Borrelia burgdorferi infection transmitted by wild Ixodes scapularis ticks

A randomized, blinded, negative controlled study was conducted to determine whether treatment with afoxolaner (NexGard^®, Merial, Inc.) would prevent the transmission of Borrelia burgdorferi to dogs by wild caught Ixodes scapularis ticks. Twenty healthy dogs were randomly assigned to two groups of ten dogs each. Ten dogs were treated orally on Day 0 at a dose near the minimum recommended dose of afoxolaner of 2.5 mg/kg (actual doses 2.5–3.1 mg/kg) and ten control dogs were not treated. On Day 28, each dog was infested with approximately 50 adult unfed wild caught I. scapularis that had a 67% B. burgdorferi infection rate (determined by polymerase chain reaction). On Day 33, live ticks were counted and removed. No ticks were found on treated dogs while control dogs had an average of 21.4 ticks. To detect infection, the B. burgdorferi-specific C6 antibody SNAP^® 4Dx^® test (IDEXX) was performed on serum collected before infestation (all dogs seronegative on Days -6 and 27) and on Days 48, 63, 77 and 92. The ten treated dogs remained seronegative through the end of the study (Day 92), while nine out of the ten control dogs were infected, as demonstrated by their seroconversion to being positive for the presence of the B. burgdorferi-specific C6 antibody starting on Day 48. In this study, all dogs treated with NexGard^® 28 days prior to challenge with wild caught I. scapularis ticks were protected from B. burgdorferi infection, while nine out of the ten untreated control dogs were infected.     

Borrelia burgdorferi infection in cats in the UK

Using an enzyme-linked immunosorbent assay (ELISA) and Western blotting techniques, cats from the north west of England and North Wales were tested for antibodies to Borrelia burgdorferi. Seropositivity to B burgdorferi in these cats was similar (4.8 per cent) to that found in dogs and horses in the UK from non-endemic areas. Cross-reactive antibodies to Leptospira interrogans serovars did not affect the cat B burgdorferi ELISA data. Clinical signs of Lyme disease were generally absent; lameness was rarely reported. As in other species, it must be considered that high levels of serum anti-borrelia antibodies are not diagnostic for clinical Lyme disease.     

Anti-histone antibodies in dogs with leishmaniasis and glomerulonephritis

The association between serum anti-histone antibodies and glomerulonephritis was studied in 43 dogs with leishmaniasis (Leishmania infantum). Dogs with increased serum creatinine levels and urine protein-creatinine ratio >1 were considered to have glomerulonephritis. Moderately elevated anti-histone antibodies were found in 38.89% (7/18) of infected dogs without glomerulonephritis, whereas 88% of dogs with glomerulonephritis (22/25) showed moderate or strongly elevated anti-histone antibodies. Prevalence of positive anti-histone antibodies reactions and mean serum concentration was significantly higher (P < 0.001; P < 0.0001) in infected dogs with glomerulonephritis. Correlation between anti-histone antibodies and urine protein-creatinine ratio was significant when groups were analysed together (P < 0.046). Positive predictive value for glomerulonephritis of positive anti-histone antibodies was 88%. In conclusion, high anti-histone antibodies are significantly associated with glomerulonephritis. Although other factors must be involved, dogs with moderate or strong positive anti-histone antibodies reactions may have a higher probability to develop glomerular lesions in canine leishmaniasis.     

Serological Confirmation of Borrelia burgdorferi Infection in Dogs in the Czech Republic

From the epidemiological point of view, dogs are very important since they are considered a suitable indicator of the spread of human borreliosis. Serum samples obtained from healthy, asymptomatic military dogs from 12 different areas in the Czech Republic were examined for IgG antibodies to Borrelia burgdorferi sensu lato (s.l.). The total of 399 serum samples were tested by a whole-cell ELISA. Specific antibodies to Borrelia burgdorferi s.l. were detected in 26 cases (6.5%). In different localities, the seroprevalence varied from 0.0% to 28.6%. Two local isolated strains Br-75 (Borrelia afzelii) and Br-97 (Borrelia garinii) were used as antigens. A total of 22 (5.5%) were positive for antibodies to Borrelia afzelii and 19 (4.8%) were positive for antibodies to Borrelia garinii. Fifteen cases were positive for both antibodies. A significantly higher seroprevalence was found in younger dogs (1–3 years) than in older ones (p < 0.05). An analysis of seroprevalence by months of sampling showed no significant difference (p > 0.05).     

Glomerular filtration rate in dogs with leishmaniasis and chronic kidney disease

BACKGROUND: Glomerular filtration rate (GFR) measurement is an indicator of kidney function. However, its usefulness in dogs at early stages of spontaneous chronic kidney disease (CKD) of glomerular origin, where routine laboratory techniques are not sufficiently sensitive, remains unproved. HYPOTHESIS: That GFR is reduced in proteinuric nonazotemic or mildly azotemic dogs with CKD secondary to leishmaniasis. ANIMALS: Twenty-six dogs with CKD secondary to leishmaniasis and 10 healthy dogs (control group). METHODS: CBC, serum biochemistry, and urinalysis (microalbuminuria and urine protein/creatinine ratio [UPC]) were performed in all dogs. GFR was calculated by measuring exogenous creatinine clearance. Based on degree of proteinuria and serum creatinine concentration (SCr), dogs were classified as group A (control; n = 10): UPC < 0.2, SCr < 1.4 mg/dL; group B (n = 8): UPC, 0.2-0.5, SCr < 1.4 mg/dL; group C (n = 10): UPC > 0.5, SCr < 1.4 mg/dL; group D (n = 5): SCr, 1.4-2 mg/dL; group E (n = 3): SCr > 2 mg/dL. Results: GFR (mL/kg/min) was 3.9 +/- 0.29, 4.4 +/- 0.74, 4.5 +/- 1.44, 2.8 +/- 0.97, and 1.5 +/- 0.43 for groups A, B, C, D, and E, respectively. Eleven dogs (1 from group B, 3 from group C, 4 from group D, and all 3 dogs from group E) had an abnormally low GFR. Four dogs from group B and 5 dogs from group C had a GFR above the upper reference range (>4.5 mL/min/kg). CONCLUSION AND CLINICAL RELEVANCE: Some proteinuric nonazotemic or mildly azotemic dogs with leishmaniasis have low GFR, but glomerular hyperfiltration occurs in other dogs.     

Spatial distribution of seroprevalence for Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis, and Dirofilaria immitis in dogs in Washington, Oregon, and California

Background: In the US little spatially defined information regarding exposure to most vector‐borne pathogens in dogs is available for the states of California (CA), Oregon (OR), and Washington (WA). Objectives: The purpose of the present study was to evaluate the spatial distribution of seroprevalence for 4 vector‐borne pathogens, Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis, and Dirofilaria immitis, across the 3 western coastal states of the contiguous United States that extend from the northern Mexican to the southern Canadian border. Methods: A convenience sample, targeting blood from 20 pet dogs per county across CA, OR, and WA, was evaluated using a canine point‐of‐care ELISA kit. Geographic coordinates of home zip code were displayed using a geographic information system. A total of 2431 dogs from CA, OR, and WA were tested. Results: The overall seroprevalence was highest for A. phagocytophilum (2.4%), followed by B. burgdorferi (1.2%), and E. canis (0.7%). The prevalence of infection with D. immitis was 0.7%. At the individual dog level, there was a significant association between seropositivity to B. burgdorferi and A. phagocytophilum (odds ratio=18.7, 95% confidence interval=6.8–47.1). For most positive results, prevalence tended to decrease with increasing latitude; thus, the highest rates of seropositivity occurred in CA, followed by OR, and then WA; one exception was seropositivity for B. burgdorferi, which was higher in WA (0.38%) than in OR (0.15%), but considerably lower than in CA (2.00%). In WA, dogs that tested positive for A. phagocytophilum, E. canis, and B. burgdorferi were in the southern Puget Sound area. For D. immitis, none of the dogs in WA was positive. Conclusions: Seropositivity for vector‐borne pathogens is broadly but patchily distributed in dogs in CA, OR, and WA.     

Serum and bronchoalveolar lavage fluid endothelin-1 concentrations as diagnostic biomarkers of canine idiopathic pulmonary fibrosis

Background: Diagnosis of canine idiopathic pulmonary fibrosis (IPF) is challenging. Endothelin‐1 (ET1) is a biomarker of IPF in humans, but whether ET1 can detect and differentiate IPF from other canine respiratory diseases is unknown. Objective: To evaluate whether measurement of the concentration of ET1 in serum and bronchoalveolar lavage fluid (BALF) can be used to distinguish canine IPF from chronic bronchitis (CB) and eosinophilic bronchopneumopathy (EBP). Animals: Twelve dogs with IPF, 10 dogs with CB, 6 dogs with EBP, 13 privately owned healthy West Highland White Terriers (WHWT), and 9 healthy Beagle dogs. Methods: Prospective, case control study. ET1 concentration was determined by ELISA in serum and in BALF. Results: No significant difference in serum ET1 concentration was detected between healthy Beagle dogs and WHWT. Serum ET1 concentration was higher in dogs with IPF (median interquartile range; 2.32 pg/mL, 2.05–3.38) than healthy Beagle dogs (1.28, 1.07–1.53; P < .001), healthy WHWT (1.56, 1.25–1.85; P < .001), dogs with EBP (0.94 0.68–1.01; P = .001), and dogs with CB (1.54 0.74–1.82; P = .005). BALF ET1 concentration was below the detection limit in healthy WHWT and in dogs with CB, whereas it was measurable in all dogs with IPF. A cut‐off serum concentration of 1.8 pg/mL had a sensitivity of 100% and a specificity of 81.2% for detection of IPF, with an area under the receiver operating characteristic curve of 0.818. Conclusions and Clinical Importance: Serum ET1 can differentiate dogs with IPF from dogs with EBP or CB. ET1 can be detected in BALF of dogs with IPF.     

Validation of a species-optimized enzyme-linked immunosorbent assay for determination of serum concentrations of insulin in dogs

Background: Measurement of canine serum insulin has relied on methods developed to measure human insulin. A species‐optimized test for measurement of serum insulin in dogs is now commercially available. Objective: The purpose of this study was to validate the canine ELISA for determination of serum insulin concentration in dogs. Methods: Precision was determined by evaluating intra‐ and interassay coefficient of variation (CV), and accuracy was determined by dilution and spike recovery studies. A method comparison study with samples from 34 clinically healthy dogs and 73 dogs examined for various illnesses and disorders (“patients”) was performed using the canine ELISA and an ELISA for human insulin. Biologic relevance of the canine assay was evaluated by measuring insulin in samples collected from 8 healthy dogs after administration of glucagon. A stability study was preformed with 6 samples stored at 20°C, 4–8°C, and ?20°C. Results: For the canine ELISA, intra‐ and interassay CVs were 4.3–7.8% and 4.4–7.7%, respectively. Mean recovery after dilution was 99% and recovery after spiking with porcine insulin was 116%. The canine and human ELISAs correlated well (r²=.94 for healthy dogs, r²=.88 for patient samples). After glucagon injection serum insulin concentrations increased significantly in 8 dogs. Insulin was stable for 30 days in 6 serum samples stored at ?20°C and in most samples for 8 days at 4–8°C. Insulin was stable for <3 days at room temperature (20°C). Conclusions: The new canine serum insulin ELISA had good precision and accuracy and correlated well with the previously used assay.     

Investigation of a screening programme and the possible identification of biomarkers for early disseminated histiocytic sarcoma in Bernese Mountain dogs

The aim of the study was to construct a screening programme for disseminated histiocytic sarcoma (DHS) in Bernese Mountain dogs using diagnostic imaging and blood analysis and evaluate blood borne biomarkers as early disease detection biomarkers. Healthy Bernese Mountain dogs were screened on four occasions in an attempt to detect early disease. Eleven blood borne biomarkers were examined for their worth as early tumour biomarkers. During 2.5 years, five dogs with early DHS were identified; four of these by diagnostic imaging. No dogs developed symptomatic DHS without being detected within 6 months of the screening programme. Only serum ferritin showed potential as a blood borne marker of the disease. Median survival times for the dogs with early DHS were 226 days. Screening programmes every 6 months for Bernese Mountain dogs over 4 years of age including diagnostic imaging and ferritin measurements may identify early DHS.     

Lyme disease antibodies in thoroughbred broodmares. correlation to early pregnancy failure

A serological enzyme linked immunosorbent assay (ELISA) for equine antibodies to Borrelia burgdorferi, the causative agent of Lyme disease, was utilized on three groups of Thoroughbred mares 14 days after breeding. Group A mares were located in Kentucky, Groups B and C mares were in Florida.Group A were broodmares from a breeding farm, where early embryonic losses were reported by the farm to be substantially higher than previous years. Of 78 mares a total of 19 (24%) had experienced early embryonic resorption. The early embryonic loss rate was 47% (8/17) in the seropositive group and 18% (11/61) in the seronegative group. The excessive loss rate in the Lyme positive group was statistically significant, with the Chi-square test yielding a p value of .014.Group B had 51 mares that did not conceive on the first breeding; Group C consisted of 51 mares that became pregnant on the first breeding, and maintained pregnancy for at least 60 days. Group C was age and farm matched to serve as controls to Group B. Group B showed a higher incidence (22%) of elevated concentrations of antibodies against B burgdorferi, than did Group C mares (16%).     

Prior joint disease is associated with increased risk of periarticular histiocytic sarcoma in dogs

Periarticular histiocytic sarcoma (PAHS) is the most common synovial tumour in dogs and is characterized by aggressive local disease with a high rate of distant metastasis. Previously, an association between PAHS and prior joint disease has been demonstrated in the Bernese Mountain Dog breed and suggested in the Rottweiler. We hypothesized that this association would be present in other breeds and investigated this via a retrospective, case‐controlled analysis. Cases were dogs diagnosed with PAHS of the stifle or elbow. Controls were age, breed and sex‐matched dogs without a diagnosis of histiocytic sarcoma. Diagnosis of prior joint disease was determined based on review of medical records and direct veterinarian and owner communications. Data were evaluated using logistic regression, 2‐sampled t tests, and chi‐squared analysis. Our study population consisted of 28 cases and 46 controls, including Flat‐Coated, Golden and Labrador Retrievers, Rottweilers, English Bulldogs, Shih Tzus, Australian Shepherds, Staffordshire Terriers and mixed breed dogs. Dogs with PAHS were more likely to have prior joint disease in the tumour‐affected joint compared with the control population (odds ratio [OR] = 13.42, P < .0001, 95% confidence interval [CI] = 4.33‐48.63). A total of 88.2% of dogs with stifle PAHS had prior joint disease in their tumour‐affected joint, most commonly cranial cruciate ligament rupture. This study confirms that the previously noted association between prior joint disease and PAHS in Bernese Mountain Dogs also applies to other breeds. Additional studies are needed to further investigate for a causal relationship.     

Androgen receptor CAG repeat polymorphisms in canine prostate cancer

Background: Relatively shorter lengths of the polymorphic polyglutamine repeat‐1 of the androgen receptor (AR) have been associated with an increased risk of prostate cancer (PC) in humans. In the dog, there are 2 polymorphic CAG repeat (CAGr) regions. Objective: To investigate the relationship of CAGr length of the canine AR‐gene and the development of PC. Animals: Thirty‐two dogs with PC and 172 control dogs were used. Methods: DNA was extracted from blood. Both CAG repeats were amplified by polymerase chain reaction (PCR) and PCR products were sequenced. Results: In dogs with PC, CAG‐1 repeat length was shorter (P= .001) by an increased proportion of 10 repeats (P= .011) and no 12 repeats (P= .0017) than in the control dogs. No significant changes were found in CAG‐3 length distribution. CAG‐1 and CAG‐3 polymorphisms proved not to be in linkage disequilibrium. Breed difference in allelic distribution was found in the control group. Of the prostate‐disease sensitive breeds, a high percentage (64.5%) of the shortest haplotype 10/11 was found in the Doberman, whereas Beagles and German Pointers had higher haplotype 12/11 (47.1 and 50%). Bernese Mountain dogs and Bouvier dogs both shared a high percentage of 11 CAG‐1 repeats and 13 CAG‐3 repeats. Differences in (combined) allelic distributions among breeds were not significant. Conclusions and Clinical Importance: In this preliminary study, short CAG‐1 repeats in the AR‐gene were associated with an increased risk of developing canine PC. Although breed‐specific differences in allelic distribution of CAG‐1 and CAG‐3 repeats were found, these could not be related to PC risk.     

Canine antibody response to Blastomyces dermatitidis WI-1 antigen

OBJECTIVE: To assess whether dogs with blastomycosis produce antibodies against the WI-1 and A-antigens of Blastomyces dermatitidis and whether the antibodies are useful in serodiagnosis. SAMPLE POPULATION: 359 serum samples obtained from 245 dogs. PROCEDURE: 233 samples from 122 dogs with blastomycosis, and 1 sample each from 24 dogs with suspected blastomycosis, 51 control dogs without infection, and 48 healthy dogs from an enzootic region were obtained. Antibodies against WI-1 antigen were detected by radioimmunoassay (RIA). Serum samples were tested in parallel for antibodies against the A-antigen of B dermatitidis by commercial agar-gel immunodiffusion (AGID) in a reference laboratory. RESULTS: Antibodies were detected in 92% of infected dogs by RIA and in 41 % by AGID. For 29 serum samples that were obtained 11 to 1,545 days after diagnosis, antibodies were detected in 92% of samples by RIA and 7% by AGID. For 93 serial serum samples from 29 dogs with blastomycosis, the mean anti-WI-1 titer was 1:18,761 at the time of diagnosis, and decreased to a mean of 1:1,338 by 210 days after treatment was initiated. Of 24 dogs with suspected infection, antibodies were detected in 67% by RIA and 33% by AGID. Control dogs without blastomycosis had no detectable antibodies in either assay. Thus, sensitivity was 92% for RIA and 41 % for AGID, and specificity was 100% for both tests. CONCLUSIONS AND CLINICAL RELEVANCE: Anti-WI-1 antibodies are readily detected by RIA in dogs with blastomycosis. Titers become high, decline during treatment, and persist for months. Anti-A antibodies are sometimes detected with AGID, but these decrease quickly.     

Anti-insulin antibodies in diabetic dogs before and after treatment with different insulin preparations

Background: Anti‐insulin antibodies (AIA) occur in diabetic dogs after insulin therapy, although their clinical significance is unclear. Hypothesis: Treatment of diabetic dogs with heterologous insulin is more likely to stimulate production of AIA than is treatment with homologous insulin. Animals: Diabetic dogs sampled before insulin therapy (n = 40), diabetic dogs sampled following treatment with porcine (homologous) insulin (n = 100), bovine (heterologous) lente insulin (n = 100), or bovine protamine zinc (PZI) insulin (n = 20), and nondiabetic control dogs (n = 120). Methods: Prospective observational study. Sera were analyzed by ELISA for antibodies against porcine insulin, bovine insulin, insulin A, B, or C peptides, and control antigens; canine distemper virus (CDV) and canine thyroglobulin (TG). Canine isotype‐specific antibodies were used to determine total and anti‐insulin IgG1 : IgG2 ratios. Results: There was no difference in CDV or TG reactivity among the groups. AIA were detected in 5 of 40 newly diagnosed (untreated) diabetic dogs. There was no significant difference in AIA (ELISA optical density reactivity) comparing control and porcine insulin‐treated diabetic dogs (P > .05). Anti‐insulin reactivity was most prevalent in bovine PZI insulin‐treated dogs (90%; P < .01), and bovine lente insulin‐treated dogs (56%; P < .01). AIA induced by treatment were enriched for the IgG1 isotype. Conclusions and Clinical Importance: This study indicates that bovine insulin is more immunogenic than porcine insulin when used for treatment of diabetic dogs.     

Efficacy of an amitraz-impregnated collar in preventing transmission of Borrelia burgdorferi by adult Ixodes scapularis to dogs

OBJECTIVE: To determine whether an amitraz-impregnated collar could prevent transmission of Borrelia burgdorferi by Ixodes scapularis to dogs. DESIGN: Laboratory trial. ANIMALS: 8 specific-pathogen-free Beagles. PROCEDURE: On days -15 and -1, all dogs had negative ELISA results for serum antibodies against B. burgdorferi. On day 0, 4 dogs were each fitted with an amitraz-impregnated (9%) collar, and 4 dogs served as untreated controls. On day 7, all dogs were infested with 100/scapularis (approx 50 females and 50 males) with a known B. burgdorferi infectivity rate of 39.4%. On days 21, 28, 35, 42, 56, 70, and 84, each dog was tested for serum antibodies against B. burgdorferi via ELISA and a western blot technique. Additional ELISA were also performed for serum antibodies against antigenically similar organisms. RESULTS: By day 70, all control dogs had developed serum ELISA responses ranging from 328 to 510 kinetics-ELISA units (equivalent to end-point titers of approx 43,500 to 60,000), whereas treated dogs remained seronegative throughout the study. Western blot assays performed on all serum samples confirmed that antibodies detected in control dogs reflected responses to specific antigens of B. burgdorferi, whereas treated dogs had no such antibodies. Additional serologic analyses confirmed that antibody responses observed in control dogs were not attributable to antigenically similar organisms. CONCLUSIONS AND CLINICAL RELEVANCE: Amitraz-impregnated collars prevented transmission of B. burgdorferi in 4 of 4 treated dogs and may be a useful management tool for prevention of borreliosis in dogs.