The occurrence of antibodies to Brucella canis in domestic dogs in the Federal Republic of Germany

1000 random serum samples of pet dogs were examined in the serum tube agglutination test for antibodies to Brucella canis. Agglutinating antibodies to Br. canis antigen were detected in 18 cases in a serum dilution of 1 : 50, in 29 cases in a serum dilution of 1 : 100, in 13 cases in a serum dilution of 1 : 200 and in a serum dilution 1 : 400. But the positive results of the agglutination tests were confirmed by complement fixation, agargel-precipitation and indirect immunofluorescence only in 2 cases (0,2%) with titers of 1 :200 and 1 :400. These serological findings indicate that in the Federal Republic of Germany Br. canis infections are rarely in pet dogs as compared with dogs (Beagles) held in research kennels.     

Agglutinins to Brucella canis in stray dogs from certain counties in Illinois and Wisconsin.

In a serologic and blood culture survey for Brucella canis in 2,572 pound dogs from eight Illinois and Wisconsin counties, 173 (6.7%) were reactive in a presumptive slide test, 41 (1.5%) were reactive in a tube agglutination test, and 6 (0.2%) were positive in blood culture.     

Serological and bacteriological detection of Brucella canis infection of stray dogs in Moreno, Argentina

A focus of B. canis infection was identified in Moreno, Argentina, among the stray dog population by serologic methods and confirmed in a second survey which included cultural isolations. A counterimmunoelectrophoresis technique using a specific rough Brucella surface antigen was applied to the serodiagnosis of canine brucellosis. This method was found to be as effective as the mercaptoethanol tube agglutination test and the gel diffusion test in detecting B. canis antibodies in natural and experimentally infected animals. The results are discussed in terms of the diagnostic significance of the three tests employed.     

Seroprevalence of Toxoplasma gondii antibodies in stray cats and dogs in the Bangkok metropolitan area, Thailand

Cats and dogs are the most popular pet animals worldwide. Cats are the natural reservoir of Toxoplasma gondii and excrete the resistant oocyst to environments. On the other hands, dogs play a role in the mechanical transmission of the parasite. Stray cats and dogs in the Bangkok metropolitan area are becoming a public concern because there is a considerable increase in their number annually. These facts indicate the risk of mechanically spreading zoonoses including toxoplasmosis to humans since human acquire the infection from infected mammals, either directly or indirectly. In the present study, the presence of T. gondii antibodies was examined in 592 cats and 427 dogs from October 2001 to September 2002 by using a latex agglutination test. T. gondii antibodies were detected in 65 (11.0%) of the 592 cats and 40 (9.4%) of the 427 dogs. The antibody titers in the positive animals ranged from 1:64 to 1:2048. Seroprevalence was significantly higher in female cats than in male cats. The present study suggested that T. gondii was widespread in the stray animals in the Bangkok metropolitan area; therefore, it is essential to control the number of stray cats and dogs in order to reduce the transmission of toxoplasmosis to animals and humans.     

A rapid slide agglutination test for the serodiagnosis of Brucella canis infection that employs a variant (M-) organism as antigen

An improved antigen is described for use in the serodiagnosis of canine brucellosis. The novel antigen employs a less mucoid (M-) variant of B. canis. The replacement of Brucella ovis with B. canis (M-) cells as antigen in slide agglutination tests would increase accuracy by reducing the rate of false positive results from ca. 50% to ca. 10%. Rose bengal stained B. canis (M-) cells are slightly more sensitive than the commercially available Brucella ovis as slide test antigens. Both test procedures require brief (less than 1 min) reaction with 2-mercaptoethanol in order to reduce the rate of false positive reactions.     

Diskospondylitis associated with Brucella canis infection in dogs: 14 cases (1980-1991).

A retrospective study of 135 dogs with diskospondylitis revealed 14 dogs with concurrent Brucella canis infection. Sexually intact male dogs and dogs in the southeastern United States appeared to be at higher risk. Results of bacteriologic culturing of blood were less likely to be positive for dogs with diskospondylitis caused by B canis infection than for dogs with diskospondylitis caused by other organisms. Follow-up evaluation of 13 of the 14 dogs revealed complete remission of clinical signs in nine, but serologic test results continued to be positive for B canis infection long after resolution of clinical abnormalities. Radiographic follow-up evaluation in 6 dogs revealed active lesions despite complete remission of clinical abnormalities.     

A Serological Survey of Dogs for Brucella canis in Southwestern Ontario

Sera from 2 000 dogs from southwestern Ontario were tested for antibodies to Brucella canis by a rapid slide agglutination test. The 100 positively reacting sera were tested by tube agglutination and immunoprecipitation (gel diffusion) tests. Thirty-one of these sera gave suspicious titres and one a positive titre in the tube agglutination test. Six of the rapid slide test positive sera gave positive reactions in immunoprecipitation tests. One dog was identified which was found to have a history very suggestive of B. canis infection. It was judged that 0.3% of sera tested showed serological evidence of B. canis infection. The complexities of the serological diagnosis of B. canis infection was apparent, in particular the tendency to false-positive results in the rapid slide agglutination test.     

Serological evidence of Ehrlichia spp. exposure in cats from northeastern Spain

There is little information about Ehrlichia canis as an infectious agent in cats. In order to estimate the prevalence of antibodies to E. canis in the feline population, 235 cat sera were analysed by indirect fluorescent-antibody test. With the objective to determine some risk factors associated with seropositivity, serum samples were divided into two groups: urban stray cats and pet cats. The seroprevalence detected was 17.9%. Most positive sera (83.3%) showed low antibody titres (<1:80). Seropositivity was very similar when comparing the two groups of animals: 17.4% in urban stray cats and 18.4% in pet cats. Results revealed that cats are exposed to Ehrlichia spp. infection, as the low antibody titres detected and the serological cross-reactivity between Ehrlichia species do not allow us to confirm E. canis exposure.     

Brucella suis biotype 1 infection in a dog

Brucella suis biotype 1 was isolated from the semen of a dog with hindlimb weakness and a large, firm, left epididymis. A semen sample was oligospermic, with many neutrophils, the numbers of which decreased in serial sampling. A card agglutination test for B abortus and a rapid slide agglutination test for B canis were positive. The modified 2-mercaptoethanol slide agglutination test for B canis and the agar gel immunodiffusion test, using B canis cell wall antigen, were negative. At necropsy, chronic granulomatous inflammation was found in, and B suis biotype 1 was isolated from, the left epididymis and prostate gland.     

Risk of Toxocara canis eggs in stray and domestic dog hair in Egypt

The aim of the study was to assess whether the hair of stray and domestic dogs in Egypt was contaminated with the eggs of the zoonotic parasite Toxocara canis, and also to identify risk factors for T. canis for contamination. Paired samples of hair and feces were collected from 53 stray and 47 domestic dogs, and hair samples were obtained from a further 11 stray and 9 domestic dogs. All samples were examined to identify T. canis eggs and, if eggs were found, their maturation stage. Eggs were identified in 26.6% of stray and 10.7% of domestic dog's hair samples. A significantly increased risk of embryonated T. canis eggs in hair samples was found in stray dogs (p=0.04), stray dogs had 3.18 (95% CI: 1.04-9.74) times the odds of having T. canis eggs present compared with domestic dogs. There was also a significant difference (p=0.02) between the mean quantity of eggs per gram in stray (77.6±6.54) and domestic (48.7±6.65) dog's hair. Fecal examination found a T. canis egg prevalence of 35.8% and 21.3% in stray and domestic dogs, respectively. As no domestic dogs which were positive from hair samples had negative fecal samples, this indicates that the presence of T. canis eggs in hair is probably due to self contamination. Two stray dogs had positive hair samples but negative fecal samples indicating that contamination may also be environmental. As both non-embryonated and embryonated T. canis eggs were found in the hair of domestic dogs, direct contact with dogs may be a potential risk factor for transmission of T. canis eggs to humans.     

Evaluation of a microplate agglutination test (MAT) for serological diagnosis of canine brucellosis

A microplate agglutination test (MAT) was compared with the tube agglutinin test (TAT), a standard test for the diagnosis of Brucella canis, in terms of the sensitivity and specificity. The results showed that MAT was more sensitive, simpler to perform and easier to read the results than TAT. On top of that the MAT allows us to handle a larger number of samples at once. Using this method we conducted sero-surveillance of the prevalence of B. canis in dogs kept in an Animal Shelter located in Kanagawa Prefecture. Twelve of 485 (2.5%) showed seropositive against B. canis. These results indicate that B. canis infection in dogs is still occurring in Japan.     

Efficacy of a modified polymerase chain reaction assay for detection of Ehrlichia canis infection.

Detection of Ehrlichia canis in acutely infected and convalescent dogs is important for effective treatment and control. However, accurate detection has been difficult to achieve, in part because dogs that have been treated therapeutically often remain seropositive for extended periods. A new method, polymerase chain reaction (PCR) assay using biotinylated E. canis-specific primers (PCR-BP), was developed for detection of E. canis. Four dogs experimentally infected with E. canis by intravenous inoculation of whole blood from carrier dogs and 2 naturally infected convalescent carriers were used to compare the specificity and sensitivity of the new method with that of microscopy/blood smear evaluation, serologic test, and conventional PCR assay using E. canis-specific primers. In experimentally infected animals, infection was detected as early as 7 days post-exposure using PCR-BP. Although the 2 naturally infected dogs were positive by serologic test and PCR-BP, both were negative by conventional PCR. Results suggest that the new method is a sensitive assay for detection of E. canis infection. In addition, results were obtained more rapidly than with other PCR-based assays.     

An ELISA test to detect antibody to Bordetella bronchiseptica

An enzyme-linked immunosorbant assay (ELISA) was developed to measure antibody to $\text{Bordetella bronchiseptica}$ in dogs. The ELISA test was more rapid and sensitive and required 50 to 150 times less antigen than the amount of antigen required for the conventional tube agglutination test. A survey of 50 canine serum samples using ELISA suggested that 8% of all sera had titers greater than 1:64, 56% had titers of 1:8 to 1:64, and 36% had titers of less than 1:8. The mean titer of survey sera was 1:46 and the median titer was 1:16. Serum antibody responses in dogs inoculated with a commercially available bacterin were compared with responses in dogs inoculated with experimental endotoxin depleted bacterin.     

A serological survey of Ehrlichia canis, Ehrlichia equi, Rickettsia rickettsii, and Borrelia burgdorferi in dogs in Oklahoma

Serum samples from 259 dogs were tested for antibodies to Ehrlichia canis, Ehrlichia equi, Rickettsia rickettsii, and Borrelia burgdorferi using the indirect fluorescent antibody test. The sera were obtained from submissions to the Oklahoma Animal Disease Diagnostic Laboratory during a 14-month period from June 1986 through July 1987. The rate for positive antibody titers to E. canis was 53%, to E. equi was 33%, to R. rickettsii was 38%, and to B. burgdorferi was 18%. Higher percentages of sera serologically positive to E. canis were found in the spring through the fall months, but there were no seasonal variations for E. equi, R. rickettsii, and B. burgdorferi. There was no consistent pattern of titers to the 4 antigens when age-groups of the dogs were compared. Forty-four different breeds were tested.     

Comparative performance of tests using cytosolic or outer membrane antigens of Brucella for the serodiagnosis of canine brucellosis

Although some ELISA tests using cytoplasmic or outer membrane antigens of Brucella have been developed to improve the diagnosis of canine brucellosis, the performance of these assays has not been compared. In the present study three ELISA tests using lipopolysaccharide (LPS)-free cytoplasmic proteins (CPs) of Brucella abortus, the lumazine synthase (LS) of Brucella spp. or a hot-saline (HS) extract of Brucella canis containing outer membrane antigens were used to test sera from dogs with suspected or confirmed brucellosis (n=36) and from dogs with pathological conditions other than brucellosis (n=212). In the first group the proportion of positive results was 92, 92 and 81% for the ELISAs with HS, CP and LS, respectively, and 94% of the samples were positive by at least one ELISA test. Three dogs that were negative by agglutination (2ME-RSAT) had a positive result by at least one ELISA, and this discrepancy was attributed to the lower analytical sensitivity of agglutination tests. This hypothesis was confirmed by a serological follow-up of seven dogs recently infected with B. canis in three of which the illness was diagnosed earlier by one or more ELISA tests than by 2ME-RSAT. Among dogs having pathological conditions other than brucellosis, specificities were 94.3, 96.7 and 96.7% for the ELISAs with HS, CP and LS, respectively. This study shows that HS-ELISA and CP-ELISA are highly specific and sensitive for the diagnosis of canine brucellosis and can detect the infection by B. canis shortly after the exposure to the pathogen.     

Contamination of dog hair with eggs of Toxocara canis

Toxocara canis, the common intestinal nematode of dogs and foxes, is the parasite responsible for human toxocarosis. It has recently been shown that dogs may harbour eggs of the parasite in their fur. To further investigate this claim a population of 100 stray dogs was examined to establish the prevalence and intensity of adult toxocaral worm infection in the intestines and eggs harboured in the hair. A novel method of washing the eggs from the hair was used. Sixty-seven percent of dogs were found to have T. canis eggs on their hair with a mean egg retrieval of nearly 584 eggs per gram from positive dogs. The age of the dog was found to be the only significant factor to influence the prevalence and intensity of eggs, with 95% of all the eggs recovered found on puppies. Thirty-nine percent of dogs were found to have adult T. canis worms in their intestine, although a significantly higher percentage of puppies (80%) were infected with worms than adults (22.5%). Puppies also had more worms per infection than adults and have a strong positive correlation between egg and worms numbers whereas adults did not. These studies show that stray dogs, particularly puppies, potentially harbour considerable numbers of eggs on their hair, at densities far higher than those reported in the soil or the general environment.     

Comparison of results for serologic testing and a polymerase chain reaction assay to determine the prevalence of stray dogs in eastern Tennessee seropositive to Ehrlichia canis

OBJECTIVE: To determine the prevalence of stray dogs in eastern Tennessee seropositive to Ehrlichia canis and examine the correlation between results for an ELISA, indirect immunofluorescent antibody (IFA) test, and polymerase chain reaction (PCR) assay. SAMPLE POPULATION: Blood samples obtained from 90 adult dogs admitted to an animal shelter in eastern Tennessee. PROCEDURE: Serum samples were analyzed for antibodies against E. canis by use of a commercially available ELISA kit, 2 IFA tests, and a PCR assay; testing was performed at the University of Tennessee (TN) and North Carolina State University (NCSU). The PCR amplification was performed by use of DNA extracted from EDTA-anticoagulated blood and primers designed to amplify DNA of Ehrlichia spp. RESULTS: Antibodies against E. canis were detected in only 1 dog by use of the ELISA. By IFA testing at TN, 10 of 90 (11%) dogs were seroreactive against E. canis antigens, all of which had medium to high titers to E. canis. Only 5 of the 10 TN seroreactors were also reactive against E. canis antigens in IFA tests conducted at NCSU, and all 5 had low to medium titers. The DNA of Ehrlichia spp was not amplified in any blood samples by use of PCR assays conducted at the TN or NCSU. CONCLUSIONS AND CLINICAL RELEVANCE: The discordant ELISA, IFA, and PCR results obtained in this study were unexpected and may have been related to exposure of dogs to an Ehrlichia species other than E. canis, such as E. ewingii.     

Brucella canis osteomyelitis in two dogs with total hip replacements

Brucella canis was isolated from the cement or bone surrounding a hip prosthesis after total hip replacement was performed for treatment of hip dysplasia in 2 dogs. Lameness or signs of infection were not evident for 9 and 16 months after surgery. Osteomyelitis surrounding the prostheses was detected radiographically only after the lameness developed. The origin of the B canis infection in the 2 dogs was believed to be hematogenous because of the biologic behavior of this organism and because of the duration of excellent limb function after hip replacement. A slide agglutination test for B canis should be performed as a screening test on any canine total hip candidate when the anamnesis and physical examination indicate that the dog may have been exposed to or infected with B canis.     

Is the detection of anti-Rhipicephalus sanguineus (Rs24p) antibodies a valuable epidemiological tool of tick infestation in dogs?

Antibodies against the 24 kDa Rhipicephalus sanguineus (Rs24p) protein were detected by ELISA to evaluate the relationship between antibodies and tick infestation. The mean titer of 3 dogs that underwent 2 experimental infestations with adult ticks was transiently increased after the second infestation. There was a significant difference in mean titers between positive control dogs naturally infested with ticks and tick-naive dogs. These results suggested that anti-Rs24p antibodies detected by ELISA are a marker of tick exposure. There was no significant difference in mean titers between tick-naive dogs and seropositive dogs to Ehrlichia canis. Some dogs positive for E. canis antibodies showed, however, higher titers than most tick-naive dogs. R. sanguineus may be related to the E. canis infection in Japan.     

Seroprevalence of Brucella abortus and B. canis in household dogs in southwestern Nigeria: a preliminary report

A preliminary serological study of 366 household dogs in Lagos and Ibadan, southwestern Nigeria, was carried out to determine antibodies due to exposure to Brucella abortus and B. canis, using the rose bengal test (RBT) and the rapid slide agglutination (RSA) test, respectively. Results showed that 5.46 % (20/366) and 0.27 % (1/366) of the dogs screened were seropositive to B. abortus and B. canis, respectively. Of all dogs, 36 had a history of being fed foetuses from cows and 11 (30.6 %) of these tested positive in the RBT. Our findings, although based on a limited sample size and a dearth of clinical details, revealed that dogs in Nigeria may be infected with Brucella spp. given the wide range of risk factors. Further studies are recommended to elucidate the epidemiology of brucellosis in dogs and its possible zoonotic consequences in the country.