Evaluation of a serological test system for the diagnosis of natural Echinococcus granulosus infection in dogs using E. granulosus protoscolex and oncosphere antigens

Serum antibody responses in feral or domesticated dogs naturally infected with Echinococcus granulosus or/and other common helminths were examined in an enzyme-linked immunosorbent assay (ELISA) using antigens prepared from E. granulosus protoscoleces or oncospheres. The ELISA using the protoscolex antigen was optimised with serums from experimental dogs monospecifically infected with E. granulosus or other helminth parasites, and helminth-free dogs. Anti-protoscolex antibody was detected in 16 of 22 (72.7%) serums from feral dogs with E. granulosus burdens ranging from 300 to 302,600 worms per dog. Seven serums from feral dogs which did not harbour E. granulosus at autopsy but which originated from an endemic hydatid region were tested using protoscolex antigen, and 1 serum gave a positive reaction. One hundred and two serums from dogs known never to have been infected with E. granulosus all gave negative reactions to protoscolex antigen. The sensitivity of the ELISA test proved to be superior to that which has been achieved by arecoline purging as a method of diagnosis for E. granulosus infection in dogs. For use of the assay in hydatid control or eradication campaigns, its sensitivity can be increased by choosing a lower absorbance discrimination value above which serums are regarded as having positive reactions. However, this does introduce positive reactions of some serums from dogs infected with helminths other than E. granulosus. In further development of the assay, use of defined recombinant antigens may improve both sensitivity and specificity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Indirect hemagglutination for the diagnosis of Heterobilharzia americana infections in dogs

An indirect hemagglutination test was developed for the diagnosis of canine schistosomiasis. Specific-pathogen-free dogs and dogs infected with a variety of other helminths were experimentally infected with Heterobilharzia americana. Sera collected at various times after the dogs were exposed to cercariae were evaluated. Glutaraldehyde-fixed sheep erythrocytes sensitized with whole adult worm antigens provided a stable antigen substrate when tested over a period of months. The test produced sensitive and specific diagnosis at an appropriate serum dilution. Serum dilutions less than 1:80 from dogs with other helminth infections resulted in nonspecific agglutination. By postexposure day 60, coinciding with the end of the prepatent period, serum titers of dogs infected only with H americana equaled, and then surpassed, those of the other dogs.     

Bovine rotavirus diagnosis: comparison of various antigens and serological tests

Agar gel immunodiffusion (AGID) and counter-immunoelectrophoresis (CIEP), complement fixation (CF), radio-immunoassay (RIA), haemagglutination (HA) and haemagglutination inhibition (HI) tests were compared in their efficiency for the detection of bovine rotavirus antigens and antibodies. As a test for antigen using hyperimmune serum, CIEP was found to have advantages over AGID by being more rapid as well as approximately four times more sensitive regardless of whether the antigen was of faecal or tissue culture origin. The CF test was more sensitive than either of the immunodiffusion procedures studied for antigen detection, but was more tedious to perform and of limited use as some faecal samples exhibited anti-complementary activity. For measurement of rotavirus antibody the radio-immunoassay (RIA) was the most sensitive technique and the CIEP least sensitive. Using the RIA a limited survey of cattle demonstrated that approximately 75% of the animals tested possessed specific antibody to rotavirus.     

Molecular and serological diagnosis of Bartonella infection in 61 dogs from the United States

Background: Molecular diagnosis of canine bartonellosis can be extremely challenging and often requires the use of an enrichment culture approach followed by PCR amplification of bacterial DNA. Hypotheses: (1) The use of enrichment culture with PCR will increase molecular detection of bacteremia and will expand the diversity of Bartonella species detected. (2) Serological testing for Bartonella henselae and Bartonella vinsonii subsp. berkhoffii does not correlate with documentation of bacteremia. Animals: Between 2003 and 2009, 924 samples from 663 dogs were submitted to the North Carolina State University, College of Veterinary Medicine, Vector Borne Diseases Diagnostic Laboratory for diagnostic testing with the Bartonellaα‐Proteobacteria growth medium (BAPGM) platform. Test results and medical records of those dogs were retrospectively reviewed. Methods: PCR amplification of Bartonella sp. DNA after extraction from patient samples was compared with PCR after BAPGM enrichment culture. Indirect immunofluorescent antibody assays, used to detect B. henselae and B. vinsonii subsp. berkhoffii antibodies, were compared with PCR. Results: Sixty‐one of 663 dogs were culture positive or had Bartonella DNA detected by PCR, including B. henselae (30/61), B. vinsonii subsp. berkhoffii (17/61), Bartonella koehlerae (7/61), Bartonella volans‐like (2/61), and Bartonella bovis (2/61). Coinfection with more than 1 Bartonella sp. was documented in 9/61 dogs. BAPGM culture was required for PCR detection in 32/61 cases. Only 7/19 and 4/10 infected dogs tested by IFA were B. henselae and B. vinsonii subsp. berkhoffii seroreactive, respectively. Conclusions and Clinical Importance: Dogs were most often infected with B. henselae or B. vinsonii subsp. berkhoffii based on PCR and enrichment culture, coinfection was documented, and various Bartonella species were identified. Most infected dogs did not have detectable Bartonella antibodies.     

Parasitological and serological diagnosis of Strongyloides stercoralis in domesticated dogs from southeastern Brazil

Canine strongyloidiasis is a parasitic infection caused by the nematode Strongyloides stercoralis and presents a great zoonotic potential. Its confirmation, using coproparasitological methods, is difficult. The detection of serum specific antibodies, however, may facilitate the diagnosis. The aims of this study were to determine the presence of S. stercoralis through the use of parasitological methods and to detect specific antibodies to the parasite in serum samples from domestic dogs by using the indirect fluorescent antibody test (IFAT) on slides and the enzyme-linked immunosorbent assay (ELISA). A total of 215 dogs of various breeds, from the cities of Uberlandia, Araxá and Campo Belo in the State of Minas Gerais, were examined and distributed according to age into the following groups: (I) 19 males and 20 females of 1-2 months old; (II) 11 males and 20 females of 2-month- to 1-year-old and (III) 41 males and 104 females, from 1 to 7 years old. Coproparasitological results showed that 63/215 (29.3%) of the dogs presented some kind of parasite, with two (0.9%) dogs (one from Araxá and the other from Uberlandia) passing S. stercoralis larvae in the feces. Serological results revealed antibodies to S. stercoralis in 45/215 (20.9%) of the dogs, with seropositivity rates of 0% (0/39) in Group I, 22.6% (7/31) in Group II, and 26.2% (38/145) in Group III. No serological cross-reactivity between S. stercoralis and hookworms or Ascaridae was found. Hookworm infections were seen in 31 dogs, but only one of these dogs (infected with both hookworm and Cystoisospora spp.) was S. stercoralis seropositive by IFAT. The present study demonstrated, for the first time, natural S. stercoralis infections in dogs diagnosed by coproparasitological and serological methods. It was concluded that the detection of specific antibodies to S. stercoralis by IFAT and ELISA may contribute to the diagnosis of canine strongyloidiasis.     

An overview of serological tests currently available for laboratory diagnosis of parasitic infections

Current methods and commercial test systems for the diagnosis of parasitic infections in both animals and humans are reviewed. Lists of test kits and their manufacturers are provided along with ordering information: the only commercially available test kits are for the diagnosis of toxoplasmosis in humans or animals and dirofilariasis (heartworm) in dogs. A partial list of diagnostic laboratories and the parasite tests they perform is also provided. Complete lists of diagnostic tests that could be obtained in the private sector are not available but would be useful. Two microfluorometric solid-phase assay systems are reviewed, and adaptations to custom assays for several kinds of parasites are briefly described. User problems in performing tests and interpreting results are stressed with emphasis placed on diagnosis of dirofilariasis in dogs. False-positive serology in dogs without heartworms and negative antibody responses in micro-filariae-positive animals are discussed with respect to proper interpretation of results.     

Specificity of the carbon immunoassay (CIA) test for the diagnosis of Toxoplasma infections.

A rapid and low cost procedure, the carbon immunoassay (CIA) test, was evaluated for the diagnosis of Toxoplasma gondii infections. Using a closely related parasite (Besnoitia jellisoni) as antigen, and homologous or heterologous immune sera, it was demonstrated by light and electron microscopy that CIA is a very reliable and specific test. As it is neither expensive nor time-consuming, it can be recommended for general and routine laboratory use.     

Comparison of some serological methods and coproscopic examinations for diagnosis of Giardia spp. invasion in dogs

Giardiasis was detected in 53.5% of dogs examined by FASTest Giardia Strip for use in dogs. Using the ProSpecT Giardia EZ Microplate Assay 52.2% of these results was confirmed. Cysts of Giardia spp. were found only in 6.5% of samples of feces examined by flotation or decantation techniques. The examinations confirmed problems with coproscopic diagnosis of giardiasis in dogs. They confirmed the greater usefulness of FASTest Giardia Strip for immunodiagnostic of giardiasis in carnivores.     

Validation of a Leishmania infantum ELISA rapid test for serological diagnosis of Leishmania chagasi in dogs

Canine visceral leishmaniasis (CVL) is caused by Leishmania donovani complex parasites including L. donovani, Leishmania infantum and Leishmania chagasi. As some studies suggest that L. chagasi and L. infantum may be very similar or even the same species, the aim of the present study was to evaluate a commercial rapid ELISA test, originally designed for L. infantum, in the diagnosis of CVL in dogs naturally infected by L. chagasi. A total of 400 serum canine samples, including 283 positive dogs for CVL from an endemic area, 86 clinically healthy dogs from a non-endemic area and 31 dogs seropositive for confounding infectious agents (Trypanosoma cruzi, Toxoplasma gondii, Neospora caninum, Babesia canis and Ehrlichia canis) were used for test validation. An overall sensitivity of 94.7% (95% CI=91.41-97.01%) and specificity of 90.6% (95% CI=83.80-95.21%) was found, with a high degree of agreement (k=0.8445) to the indirect ELISA. When confounding infectious diseases were excluded, specificity increased to 100% (95% CI=95.8-100%), with a higher degree of agreement (k=0.8928). In conclusion, the commercial kit designed for L. infantum was a highly sensitive and specific device for detection of L. chagasi infection in dogs, which indicates high immunoreactivity similarities between L. infantum and L. chagasi.     

Evaluation of an enzyme-linked immunosorbent assay (ELISA) for the serological diagnosis of sarcoptic mange in dogs

Canine scabies is a challenging disease to diagnose because sarcoptic mites are hard to find on skin scrapings. The purpose of this study was to evaluate a serologic enzyme-linked immunosorbent assay (ELISA) as an aid in the diagnosis of canine scabies. In addition, serum samples were obtained post treatment to determine the duration and persistence of circulating scabies antibodies after resolution of natural infection. Nineteen dogs diagnosed with sarcoptic mange and 38 control dogs were tested. Sixteen scabies-infested dogs showed positive pretreatment ELISA results (84.2% sensitivity). Thirty-four control dogs showed negative ELISA results (89.5% specificity). In the 11 scabies dogs from which multiple post treatment serum samples were obtained, detectable antibodies were not present 1 month after treatment in four cases, but were present for 1-4.5 months post treatment in seven dogs. Our results suggest that this scabies ELISA test is useful in the diagnosis of canine scabies.     

Comparison of three techniques for the diagnosis of urinary tract infections in dogs with urolithiasis

OBJECTIVES: To identify an appropriate sampling technique(s) to accurately detect the bacteria causing urinary tract infections in dogs with urolithiasis. METHODS: Twenty-one dogs with urolithiasis were included in the study. Three types of samples were taken from each dog. Urine was collected by cystocentesis, and a urinary bladder mucosal biopsy and urolith were retrieved during cystotomy. The samples were then cultured on blood agar and MacConkey's agar to identify the bacteria associated with urinary tract infections. RESULTS: Bacterial urinary tract infection was found in 16 cases (76.19 per cent). The most prevalent bacteria found to cause urinary tract infection were Escherichia coli (n=7), followed by coagulase-positive Staphylococcus species (n=4), Klebsiella pneumoniae (n=2), Pseudomonas aeruginosa (n=2) and Proteus mirabilis (n=1). In the case of a positive urine culture, the same bacteria were also cultured from the urinary bladder mucosal biopsy alone or from both the urinary bladder mucosal biopsy and urolith. However, in the case of a negative urine culture, bacteria were found to be present in the urinary bladder mucosal biopsy or urolith cultures in 23.81 per cent of dogs. The uroliths that gave positive culture results were either infection-induced uroliths composed of struvite and calcium carbonate phosphate, ammonium acid urate only or metabolic uroliths composed of calcium oxalate and calcium phosphate, or calcium phosphate only. All the uroliths that gave negative culture results were metabolic uroliths composed of calcium oxalate and/or calcium phosphate, and uric acid and calcium phosphate. CLINICAL SIGNIFICANCE: When the culture from the urine obtained by cystocentesis is negative, cultures of urinary bladder mucosal biopsy and urolith are recommended in dogs with urolithiasis in order to accurately assess the microbiological status of the urinary tract.