Epidemiology, diagnosis, and treatment of blastomycosis in dogs and cats

Blastomycosis is one of the most common systemic fungal diseases in dogs in North America, but it is rarely diagnosed in cats. The typical route of infection is inhalation of aerosolized conidia of Blastomyces dermatitidis. From the respiratory tract, the developing yeast form may disseminate throughout the body and affect multiple organ systems, most commonly the lymphatic, skeletal and central nervous systems, eyes and skin. Disseminated disease often is associated with nonspecific signs of illness including lethargy, inappetence and fever, as well as signs referable to specific organ systems like chronic cough and dyspnea, peripheral lymphadenopathy, endophthalmitis, and central nervous signs. Diagnosis is typically made by detection of Blastomyces dermatitidis yeast in affected tissues by fine-needle aspiration cytology or histopathology. The treatment of choice is itraconazole. Prognosis is fair in dogs without central nervous disease and guarded in cats.     

Evaluation of the prevalence of infections in cats after renal transplantation: 169 cases (1987-2003)

OBJECTIVE: To determine the prevalence of infections developing postoperatively, document the contribution of infection to increased risk of death, and identify risk factors associated with the development of infectious complications in cats after renal transplantation. DESIGN: Retrospective study. ANIMALS: 169 cats that received renal allograft transplants. PROCEDURES: Medical records of cats receiving renal transplants at the University of California from January 1987 through December 2003 were reviewed. RESULTS: 47 infections developed in 43 of 169 cats. Bacterial infections were most common (25/47 cats), followed by viral (13/47), fungal (6/47), and protozoal (3/47) infections. The median duration from transplant surgery to development of infection was 2.5 months. Infection was the second most common cause of death after acute rejection of the transplant, accounting for 14% of deaths overall. Cats with concurrent diabetes mellitus had a significantly increased risk of developing an infection after renal transplantation. Sex, increasing age, concurrent neoplasia, and previous treatment for transplant rejection were not associated with development of infection. CONCLUSIONS AND CLINICAL RELEVANCE: Infection was a common complication and an important cause of death or euthanasia in cats after renal transplantation. Development of diabetes mellitus after transplantation significantly increased the risk of infection.     

Oesophageal strictures in cats associated with doxycycline therapy

Four cases of oesophageal stricture subsequent to doxycycline administration are reported. All cases were young to middle age (median age 3 years; range 1-7 years), and either domestic shorthair or domestic longhair breed. In all cases the predominant clinical sign was regurgitation, which developed at variable times after doxycycline administration. In all cases the reason for doxycycline use was treatment or prophylaxis of suspected infections (Mycoplasma haemofelis, Chlamydophila felis or Bordetella bronchiseptica), and the duration of therapy was variable. In one case the stricture was definitively diagnosed at post mortem examination, in the three other cases, definitive diagnosis was by endoscopy. Balloon dilation was successful in the three cases that were treated. This is the largest case series, to date, of oesophageal disease in cats associated with doxycycline administration. Caution should be exercised when administering oral medication to cats, especially doxycycline, and should be accompanied either by a water or food swallow.     

Histoplasmosis in dogs and cats

Histoplasma capsulatum is endemic throughout most of the United States with a high prevalence of infections in the Midwest and South. Histoplasmosis is the second most common systemic fungal disease in cats that may be more susceptible than dogs. Infection occurs by inhalation of conidia from the mycelial phase, which subsequently convert to the yeast form. Histoplasma capsulatum is phagocytized and harbored by cells of the mononuclear phagocyte system. Infection may be subclinical or cause clinical pulmonary granulomatous disease or dissemination. Disseminated disease predominantly affects the liver, spleen, gastrointestinal tract, bone and bone marrow, integument, and eyes. Primary gastrointestinal histoplasmosis also occurs. Clinical signs of histoplasmosis often are nonspecific, including chronic wasting, fever, anorexia, respiratory signs, and lameness. Gastrointestinal signs (eg, diarrhea with hematochezia or melena) are common in dogs. The definitive diagnosis is made by identification of the yeast in tissue samples. Itraconazole is the treatment of choice.     

TENESMUS AND STRANGURIA FROM A CYSTIC UTERINE REMNANT

A 14-year-old domestic short hair spayed female cat was examined for tenesmus and stranguria. The abdominal mass discovered was removed and found to be a cystic uterine remnant. Tenesmus and stranguria resolved following mass removal.     

Uptake of ferritin and Bordetella avium in bronchus-associated lymphoid tissue of turkeys

The uptake of macromolecular and particulate materials in bronchus-associated lymphoid tissue (BALT) in turkeys was examined using transmission electron microscopy. Tracer materials used were live and ultraviolet-killed (UV-killed) Bordetella avium and ferritin. Suspensions of bacteria and ferritin were instilled via intratracheal catheterization and allowed to remain in contact with the respiratory surfaces for 0, 10, 30, 60, 90, and 120 min. Ferritin and B. avium were taken up by both ciliated and non-ciliated cells of the epithelium overlying BALT (BALT epithelium). Ferritin was found in organelles associated with endocytosis (i.e. apical vesicles, endosomes, cytoplasmic vacuoles) and was apparently transported across epithelial cells, since it was also found in intercellular spaces. Bacteria were found in vacuoles within BALT epithelial cells, but not free in intercellular spaces. Some macrophages in BALT epithelium also contained bacteria. No differences were observed between uptake of live and UV-killed bacteria. We conclude that both ciliated and non-ciliated cells of BALT epithelium in turkeys are able to take up macromolecular and particulate materials. Bacteria are also accessible to intraepithelial macrophages, although whether they are taken up directly from the bronchial surface or whether they pass through epithelial cells first could not be determined. This evidence suggests that antigens, including respiratory pathogens, could gain access to cells of the avian immune system by transepithelial passage in BALT.     

Calcospherite-like bodies and caseous necrosis in tracheal mucus from a dog with tuberculosis

A 3-year-old Wirehaired Fox Terrier was presented to the University Veterinary Hospital, University College Dublin, for evaluation of chronic cough of 8-months duration. Bronchoscopy showed a severely dilated collapsed left principal bronchus filled with highly viscous white mucus. Cytologically, globular lipid-like material and round concentrically laminated crystalline structures were evident within the proteinaceous mucus. These findings resembled the calcospherites and granular caseous debris often observed in human tuberculous patients. A Ziehl-Neelsen-stained cytocentrifuged preparation of material obtained by bronchoalveolar lavage revealed a few acid-fast rods within macrophages, suggestive of tuberculosis. At necropsy, granulomas with caseous necrosis were present in the lung parenchyma, bronchial and mediastinal lymph nodes, liver, pancreas, and mesentery. Granulomas were adherent to both kidney capsules and to the diaphragm. Histologically, there was evidence of mild calcification within caseous granulomas, which was confirmed by von Kossa's stain. Using Ziehl-Neelsen stain, acid-fast rods were identified within granulomas; bacterial culture was positive for Mycobacterium bovis. The cytologic findings in this case have not been reported previously in dogs and demonstrate a possible correlation between tuberculosis and calcospherite-like bodies with caseous, globular material in bronchial mucus, similar to that described in human patients.