Clinical,clinicopathologic, and radiographic findings in dogs with coccidioidomycosis: 24 cases (1995-2000)

OBJECTIVE: To determine clinical, clinicopathologic, and radiographic abnormalities in dogs with coccidioidomycosis. DESIGN: Retrospective case series. ANIMALS: 24 dogs. PROCEDURE: Clinical information and results of clinicopathologic testing were obtained from medical records. Thoracic radiographs were reviewed to characterize abnormalities. RESULTS: Dogs ranged from 1 to 10 years old at the time of diagnosis, with 12 dogs being between 1 and 3 years old. Historical complaints included cough, lameness, signs of head or neck pain, and difficulty breathing. Mild anemia, neutrophilia, and monocytosis were common. All dogs had hypoalbuminemia, and 8 of 15 had hyperglobulinemia. Thoracic radiographs of 19 dogs were reviewed. Pulmonary infiltrates were seen in 13 dogs, with an interstitial pattern of infiltration being most common. Hilar lymphadenopathy was seen radiographically in 10 dogs. Serum from 20 dogs was tested for antibodies against Coccidioides immitis. One dog was positive for IgM antibodies, 5 were positive for IgM and IgG antibodies, and 14 were positive for IgG antibodies. Quantitative IgG titers measured in 14 dogs ranged from 1:2 to 1:128 (median and mode, 1:32). In 6 dogs, histologic examination of biopsy samples revealed fungal spherules ranging from 8 to 70 microm in diameter. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in dogs, coccidioidomycosis may be associated with a wide spectrum of nonspecific respiratory and musculoskeletal abnormalities. The chronic nature of the disease makes diagnosis difficult, even in regions in which the organism is endemic.     

Purification and renaturation of membrane neuraminidase from Haemophilus parasuis

Haemophilus parasuis, which causes polyserositis, polysynovitis, meningitis, septicemia, and pneumonia in pigs, has emerged as an increasing problem in modern swine production systems. Co-factors for and the pathogenesis of H. parasuis disease are not defined. One of the potential virulence factors of H. parasuis is its neuraminidase (sialidase). While purifying the H. parasuis neuraminidase from the membrane fraction, we developed a protocol to renature enzymatic activity after enzyme preparations were resolved electrophorectically in denaturing polyacrylamide gels. The H. parasuis neuraminidase co-resolved with recombinant neuraminidase of Vibrio cholera; thus its apparent molecular mass is 82 kilodalton (kDa). The H. parasuis neuraminidase was associated with the membrane fraction and the purification protocol removed over 99% of the H. parasuis cell protein while retaining over 90% of the neuraminidase activity. Purified protein will provide another avenue to clone the neuraminidase gene that has been refractory to cloning and the protocol will be a means to purify recombinant protein.     

Algal dermatitis in cichlids

Three varieties of a popular African cichlid aquarium species, Pseudotropheus zebra, from 2 tropical fish farms in east central Florida were submitted for diagnostic evaluation because of the development of multifocal green lesions. The percentage of infected fish in these populations varied from 5 to 60%. Fish were otherwise clinically normal. Microscopic examination of fresh and fixed lesions confirmed algal dermatitis, with light invasion of several internal organs in each group. A different alga was identified from each farm. Fish from farm A were infected with Chlorochytrium spp, whereas fish from farm B were infected with Scenedesmus spp. Because of the numbers of fish involved, bath treatments to remove the algae from affected fish from farm B were attempted, with different dosages of several common algaecides including copper sulfate pentahydrate, diuron, and sodium chloride. However, none of these treatments were successful, possibly because of the location of the algae under the scales and within the dermis, and also because of the sequestering effect of the granulomatous response. To our knowledge, this is the first report of algal dermatitis in ornamental cichlids, as well as the first report of Scenedesmus spp infection in any fish.     

Antimicrobial susceptibility patterns of Salmonella isolates from cattle in feedlots

OBJECTIVE: To evaluate the antimicrobial susceptibility patterns of Salmonella isolates from feedlot cattle. DESIGN: Cross-sectional study. SAMPLE POPULATION: 263 Salmonella isolates. PROCEDURES: Fecal samples were collected from the floor of 2 pens in each of 100 feedlots. Two hundred eighty Salmonella isolates were recovered after bacteriologic culture from 38 pens. Of these, 263 isolates were available for antimicrobial susceptibility testing to 16 antimicrobials, using microbroth dilution breakpoint plates. RESULTS: Less than 5% of isolates were resistant to any of the antimicrobials tested, with the exception of sulfamethoxazole (15; 5.7%) and tetracycline (61; 23.2%). Most isolates (197; 74.9%) were susceptible to all antimicrobials tested, whereas 18 (6.8%) were resistant to 2 or more antimicrobials. The percentage of isolates with resistance to any antimicrobial varied by serotype. The percentage of isolates resistant to various antimicrobials was not related to concurrent use of antimicrobials in the feed. CONCLUSIONS AND CLINICAL RELEVANCE: With the exception of tetracycline and sulfamethoxazole, resistance of Salmonella isolates to any of the antimicrobials was uncommon. Most isolates were susceptible to all antimicrobials tested. Antimicrobial resistance was not related to the presence of antimicrobials in the ration being fed at the time of sample collection.