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SUMMARY

Twenty-three clinically normal Beagles were inoculated with North American Trypanosoma cruzi isolates from an opossum (Tc-O), an armadillo (Tc-A), or a dog (Tc-D). The dogs were grouped according to the clinical outcome of inoculation. Group 1 consisted of 7 dogs inoculated with Tc-O or Tc-A that died or were euthanatized during acute stages of disease. Group 2 consisted of 5 dogs inoculated with Tc-O or Tc-A, that also developed acute disease, but survived to develop chronic disease. Group 3 consisted of 7 dogs inoculated with Tc-D neither developed acute nor chronic disease. Group 4 consisted of 4 dogs and served as noninoculated controls.

In group 1, the gross lesions were diffusely pale myocardiums with right ventricular enlargement, hepatomegaly, and a moderate amount of modified transudate in the abdominal cavity. Severe diffuse granulomatous myocarditis with large numbers of pseudocysts and minimal fibrosis characterized the tissues from all cardiac chambers and septum. The lesions were most severe in the right atrium and ventricle. Mild multifocal myositis and pseudocysts were observed in skeletal muscles and smooth muscles of the urinary bladder and small intestine. Multifocal encephalitis and pseudocysts were in the cerebral cortex, cerebellum, and brain stem.

In group 2, the gross lesions were biventricular enlargement and thinning of the ventricular free walls. The right ventricle contained the most severe microscopic changes. There were mild multifocal interstitial lymphohistiocytic cellular infiltrates, perivasculitis, and marked fibrosis in all areas of the myocardium. Mild myositis and multifocal encephalitis were seen in the skeletal muscles and brains. Pseudocysts were not observed in any tissues.

In group 3, there was mild biventricular dilatation, minimal inflammation with fibrosis in cardiac tissues, and a multifocal myositis in most skeletal muscles. Multifocal encephalitis was seen in the brain stem. Pseudocysts were not observed in any tissues. Lesions were not found in group 4.

Our results indicated heterogeneity between North American T cruzi isolates in lesion development in dogs, and there appeared to be a temporal relationship between acute and chronic trypanosomiasis in Tc-O- and Tc-A-inoculated dogs and the 3 phases of Chagas disease in human beings.

Free access
in American Journal of Veterinary Research

Summary

Efficacy of fenbendazole at 2 dosages for treating naturally acquired giardiasis in dogs was assessed. Giardia cysts were not detected in the feces of 6 of 6 group-1 dogs (as determined by use of the zinc sulfate concentration technique) after fenbendazole treatment (50 mg/kg of body weight, po, q 24 h, for 3 doses). Cysts were not detected in the feces of 6 of 6 group-2 dogs after fenbendazole treatment (50 mg/ kg of body weight, po, q 8 h, for 3 days). However, cysts were not detected in the feces of only 1 of 6 group-3 (nontreated control) dogs. Signs of toxicosis were not observed in any dog. These results indicate that the current label dosage (for the treatment of Toxocara canis, Toxascarisleonina, Ancylostoma canmum, Uncinaria stenocephala, Trichuris vulpis, and Taenia pisiformis, but not Giardia spp) of fenbendazole (50 mg/kg, po, q 24 h, for 3 doses) is also effective for treating giardiasis in dogs.

Free access
in American Journal of Veterinary Research

SUMMARY

Blood culture and serologic testing were used to study the prevalence of Trypanosoma cruzi infection in a group of 85 dogs from southern Louisiana rural environment. These dogs were known to have been in contact with wild mammalian hosts of the hemoflagellate. Results were compared with blood culture and serologic test results in 103 dogs from a rural environment and with limited known wild mammalian T cruzi host contact. Serologic test results for the 188 dogs from the rural environment were compared with results for 176 dogs from an urban animal shelter and for 100 household pet dogs from an urban southern Louisiana environment. Blood culture was not performed on urban dogs. Culture results were negative in all dogs from rural environments. Serologic evidence of infection was obtained for 4 of the 85 (4.7%) dogs of rural environment with known host contact. Of 176 dogs from the animal shelter, 4 (2.3%) had high antibody titer to T cruzi, and 11 others had low titer (< 2 adjusted elisa units [aEU]). Two and 4 dogs of the housed urban and rural groups, respectively, had antibody titer to T cruzi that was < 2 aEU. Results indicate that prevalence for exposure to T cruzi antigen is higher in dogs with high potential contact with the vector and wild mammalian hosts of T cruzi, whether they are from rural or urban environment. Furthermore, results indicate that similar studies on high-risk human populations may be indicated.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of carprofen on hemostatic variables in clinically normal dogs.

Animals—12 clinically normal Labrador Retrievers.

Procedure—10 dogs (6 females, 4 males) received carprofen (2.2 mg/kg of body weight, PO, q 12 h) for 5 days. Two dogs (untreated control group; 1 female, 1 male) did not receive carprofen. Hemostatic variables (platelet count, activated partial thromboplastin time, prothrombin time, fibrinogen, platelet aggregation, and bleeding time) were assessed for all dogs prior to treatment, on day 5 of treatment, and 2 and 7 days after discontinuation of the drug (days 7 and 12). Serum biochemical variables and Hct were assessed prior to treatment and on days 5 and 12.

Results—In dogs receiving carprofen, platelet aggregation was significantly decreased, and onset of aggregation was significantly delayed on days 5, 7, and 12, compared with pretreatment values. Activated partial thromboplastin time was significantly increased on days 5, 7, and 12 over pretreatment values in treated dogs, but values remained within reference ranges. Significant differences were not detected in buccal mucosal bleeding time, other serum biochemical and hemostatic variables, or Hct, compared with pretreatment values and the internal control group.

Conclusion and Clinical Relevance—Administration of carprofen for 5 days causes minor but not clinically important alterations in hemostatic and serum biochemical variables in clinically normal Labrador Retrievers. Carprofen is commonly used to treat osteoarthritis and chronic pain in dogs, but prior to this study, its effect on platelet aggregation and hemostatic variables was unknown. (Am J Vet Res 2001;62:1642–1646)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate serum titers obtained by use of the microscopic agglutination test (ie, MAT titers) to Leptospira interrogans serovar pomona and autumnalis and Leptospira kirschneri serovar grippotyphosa in dogs given a commercial vaccine against serovars pomona and grippotyphosa.

Animals—Forty 12-week-old puppies and 20 mature Beagles.

Procedure—Puppies received a commercial vaccine against serovars pomona and grippotyphosa at 12 weeks of age, then received a booster vaccine and 3 weeks later; mature dogs received the vaccine once. Serum MAT titers to serovars pomona, autumnalis, and grippotyphosa were measured before vaccination and at 2, 4, 6, 10, and 16 weeks after the first or only vaccination.

Results—Of the 40 puppies vaccinated, 40, 0, and 40 developed MAT titers of > 100 after vaccination to serovars pomona, grippotyphosa, and autumnalis, respectively. Microscopic agglutination test titers to serovar autumnalis were higher than MAT titers to serovars pomona and grippotyphosa and persisted in some dogs for 16 weeks (6 weeks longer than for titers to serovar pomona). Of the 20 mature dogs, 13, 5, and 20 developed MAT titers of > 100 at 2 weeks to serovars pomona, grippotyphosa, and autumnalis, respectively. Titers to serovar pomona were higher and persisted in some dogs beyond 16 weeks after vaccination, compared with titers to serovars pomona and grippotyphosa, which persisted for 10 and 6 weeks, respectively.

Conclusions and Clinical Relevance—Subunit vaccines against serovars pomona and grippotyphosa induce MAT titers not only to homologous antigens but also to serovar autumnalis, which could lead to a misdiagnosis of leptospirosis caused by serovar autumnalis. (Am J Vet Res 2005;66:1780–1784)

Full access
in American Journal of Veterinary Research

Summary

Two commercially available tests, an antigen-capture elisa for use on fecal samples, and a peroral nylon string test for use in dogs, were compared with a zinc sulfate fecal concentration technique (zsct) for detection of giardiasis in dogs. Of 77 dogs and 164 fecal samples (from these dogs), 33 and 52, respectively were found to be Giardia-positive on the basis of results of the zsct. The elisa gave false-negative results for 10 and 14% of zsct-positive dogs and fecal samples, respectively, and false-positive results (relative to the zsct test results) in 13 and 10% of zsct-positive dogs and fecal samples, respectively.

Of the 18 string-tested dogs, 14 were positive by results of the zsct. Of the 4 dogs that were Giardia-negative by zsct, 2 were Giardia-positive by elisa. Dogs were sedated and given water and metoclopramide to aid passage into the duodenum of the capsule containing a nylon string. Of the 21 string tests performed on the 18 dogs, only 5 strings reached the duodenum, and 0 of the 5 yielded positive results for Giardia sp. Because the string broke in 1 dog (leaving most in the gastrointestinal tract and, therefore, producing a risk of string foreign body) further string tests were not done.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate efficacy of a combination of praziquantel, pyrantel pamoate, and febantel at 2 dosages for treating naturally acquired giardiasis in dogs.

Animals

6 male and 9 female Beagles.

Procedure

Dogs were identified as naturally infected with Giardia sp, using the zinc sulfate concentration technique (ZSCT), and were allocated to 1 of 3 groups. Group-1 dogs were treated orally with a praziquantel (5.4 to 7 mg/kg of body weight), pyrantel pamoate (26.8 to 35.2 mg/kg), and febantel (26.8 to 35.2 mg/kg) combination, every 24 hours for 3 doses. Group-2 dogs were treated with the combination once. Group-3 dogs were nontreated controls. Four fecal samples were examined, using the ZSCT, from each dog of each group within 6 days of the last treatment. Dogs were considered to have giardiasis if 1 or more of the fecal samples had positive results for Giardia cysts. Dogs were examined daily for at least 10 days after the last treatment.

Results

Giardia cysts were not detected in the feces of any group-1 dog or in the feces of 2 of 5 group- 2 dogs. Cysts were detected in the feces of 5 of 5 group-3 (nontreated control) dogs. Signs of toxicosis were not observed in any dog.

Conclusion and Clinical Relevance

The current labeled dose (for treatment of various nematodes and cestodes, but not Giardia sp) of the combination given orally once reduces cyst excretion in Giardia-infected dogs, and should be considered for treatment of dogs shedding Giardia cysts, whether or not they have clinical signs of infection. (Am J Vet Res 1998; 59:1134-1136)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effect of a chondroprotective agent on hematologic, hemostatic, and biochemical variables in clinically normal dogs when administered over 30 days.

Animals

13 clinically normal Beagles of either sex.

Procedure

Hematologic and hemostatic variables were assessed prior to treatment and on days 3, 14, and 30 of treatment. Biochemical variables were assessed before treatment and on day 30 of treatment.

Results

Significant (P < 0.05) decreases were noted in hematocrit, hemoglobin, WBC, and segmented neutrophil variables on days 3 and 14 of treatment. A significant decrease in red distribution width was noted on days 3 and 30, in RBC count on day 3, and in lymphocyte numbers on day 30. There were also significant reductions of aggregation in response to adenosine diphosphate and collagen on days 14 and 30. Significant decreases were noted in total ATP release in response to collagen on days 14 and 30, as well as significant decrease in platelet count on days 14 and 30. No changes were noted in prothrombin time, activated partial thromboplastin time, mucosal bleeding time, or biochemical variables during the study.

Conclusions

Administration of this chondroprotective agent causes minor but not clinically important changes in hematologic and hemostatic variables in young, clinically normal dogs.

Clinical Relevance

Oral chondroprotective agents are widely prescribed in veterinary medicine for the treatment of degenerative joint disease; however, to date, little is known about safety of their use. (Am J Vet Res 1996;57:1390-1394)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Summary

Efficacy of albendazole for treating giardiasis in dogs was assessed in 3 experiments. In experiment 1, Giardia cysts were cleared from feces of 5 of 7 dogs (as determined by the zinc-sulfate concentration technique) after the dogs received a single dose of albendazole (25 mg/kg of body weight, po), whereas feces of 3 of 7 dogs became clear of cysts without treatment. In experiment 2, feces of 5 of 5 dogs became clear of cysts after albendazole treatment (25 mg/kg, po, q 12 h for 4 doses); feces of 1 of 5 untreated control dogs became clear. In experiment 3, feces of 18 of 20 dogs became clear of cysts after albendazole (25 mg/kg, po, q 12 h for 4 doses) was given; none of the 20 control dogs had feces clear of cysts. Signs of toxicosis were not observed in any dog. These results indicate that a single dose of albendazole (25 mg/kg, po) is not effective for treating giardiasis in dogs. However, 4 doses of albendazole (25 mg/kg, po, q 12 h) are highly effective and nontoxic for treatment of giardiasis in dogs.

Free access
in American Journal of Veterinary Research