Inoculation of two genotypes of Hemobartonella felis (California and Ohio variants) to induce infection in cats and the response to treatment with azithromycin

OBJECTIVES: To describe clinical and laboratory findings associated with cats experimentally infected by inoculation with the 2 recognized genotypes of Hemobartonella felis (small variant, Hfsm; large variant, Hflg) and to determine the response of cats to treatment with azithromycin. ANIMALS: 18 young adult domestic shorthair cats of both sexes. PROCEDURES: Cats were inoculated with H felis and monitored weekly, using CBC counts and a polymerase chain reaction (PCR) designed to detect both genetic variants of H felis. Beginning 26 days after inoculation, 11 cats were administered azithromycin (15 mg/kg of body weight, PO, q 12 h, for 7 days). RESULTS: Inoculation resulted in coinfection with Hflg and Hfsm, and both variants were detected by PCR. Clinical abnormalities and anemia were most severe in Hflg- and dual-infected cats. Results of PCR and CBC were positive for H felis in 112/112 (100%) and 42/112 (37.5%), respectively, samples collected after inoculation. Administration of azithromycin had little effect on clinical variables, including anemia. All cats, regardless of treatment with azithromycin, had positive results for the PCR at the end of the study period. CONCLUSIONS AND CLINICAL RELEVANCE: In these cats, Hflg was more pathogenic than Hfsm, and coinfection with both variants was detected. Results of the PCR were superior to results of CBC for detecting infection with H felis. Azithromycin administered at the dose and duration reported here was not efficacious for the treatment of cats with hemobartonellosis.     

The evolution of agriculture in ants

Cultivation of fungi for food by fungus-growing ants (Attini: Formicidae) originated about 50 million years ago. The subsequent evolutionary history of this agricultural symbiosis was inferred from phylogenetic and population-genetic patterns of 553 cultivars isolated from gardens of "primitive" fungus-growing ants. These patterns indicate that fungus-growing ants succeeded at domesticating multiple cultivars, that the ants are capable of switching to novel cultivars, that single ant species farm a diversity of cultivars, and that cultivars are shared occasionally between distantly related ant species, probably by lateral transfer between ant colonies.     

High-frequency jet ventilation during bronchoscopy in a dog

A dog with severe pulmonary disease caused by Filaroides osleri (Oslerus osleri) infection was anesthetized with thiopental sodium IV for diagnostic bronchoscopy. The dog was ventilated continuously during bronchoscopy with a high-frequency jet ventilator (using a rate of 100 breaths/min, drive pressure of 20 psi, and inspiratory fraction of 0.30). High-frequency jet ventilation provided satisfactory ventilatory support during bronchoscopy despite the dog's pulmonary disease.     

Urinary incontinence secondary to idiopathic detrusor instability: cystometrographic diagnosis and pharmacologic management in two dogs and a cat

Idiopathic detrusor instability was diagnosed as the cause of urinary incontinence in 2 dogs and a cat. The diagnosis was based on abnormal cystometrographic findings and by exclusion of other causes of detrusor hyperactivity. Anticholinergic or combined anticholinergic, antispasmodic, and local anesthetic treatment resolved the clinical signs in all 3 animals. Increased threshold volumes after treatment were documented by cystometrography in one dog and in the cat.     

Association of Hepatic Necrosis With Trimethoprim Sulfonamide Administration in 4 Dogs

Hepatic necrosis in association with trimethoprim-sulfonamide (TMS) combination therapy was diagnosed in 4 dogs based on history, clinical presentation, and examination of histopathologic specimens collected postmortem. Duration of TMS therapy prior to onset of clinical signs ranged from 4 to 30 days. The dose of TMS ranged from 18 mg/kg to 53 mg/kg bid. Despite supportive medical therapy, all dogs died or were euthanized due to hepatic failure. This report highlights the potential for hepatotoxicity during TMS therapy. Duration of therapy, type of TMS combination, and dose did not appear related to the development of toxicity. The low number of dogs affected suggests an idiosyncratic drug reaction.     

A syndrome resembling feline dysautonomia (Key-Gaskell syndrome) in a dog.

Dysautonomia, or autonomic nervous system dysfunction, was diagnosed in a 1-year-old dog. Clinical signs of disease included diarrhea, vomiting, prolapse of nictitating membranes, and urinary incontinence. Bilateral keratoconjunctivitis sicca, xerostomia, and decreased anal sphincter tone were also observed. On the basis of response to atropine, results of intradermal histamine testing and gastric motility studies, and ocular response to parasympathomimetics and sympathomimetics (direct and indirect acting), autonomic nervous system function was determined to be abnormal. Treatment with metoclopramide hydrochloride and bethanechol chloride resulted in improved attitude, appetite, Schirmer tear test response, and decrease in frequency of vomiting within 24 hours. Bladder function and anal tone improved within 3 weeks.     

Effects of dietary lysine supplementation in cats with enzootic upper respiratory disease

To determine the effectiveness of dietary lysine supplementation in cats with enzootic upper respiratory disease (URD), 50 cats were fed a ration containing 11 or 51 g lysine/kg diet for 52 days. Food intake, body weight, clinical signs, plasma amino acid concentrations and presence of Chlamydophila felis or feline herpesvirus (FHV)-1 DNA within the conjunctival fornix were assessed. Food and lysine intake of both dietary groups decreased between days 17 and 22, coinciding with peak disease and viral presence. Mean disease score for cats fed the supplemented ration (0.94) was higher than for those fed the basal diet (0.21); however, this could be attributed to a small subset of male cats which demonstrated fighting behavior that may have contributed to stress within that cage. FHV-1 DNA was detected on 12 occasions in six cats receiving the supplemented diet and on one occasion in one cat fed the basal diet. C felis DNA was never detected. Mean plasma arginine concentration was lower and plasma lysine concentration was higher in supplemented cats. Mean plasma arginine concentration declined throughout the study in both dietary groups. Data from the present study raise important questions but do not permit a definitive conclusion regarding the efficacy of dietary lysine supplementation in cats with enzootic URD.