Reactivation of Coccidioidomycosis in a Mouse Model of Asymptomatic Controlled Disease.

The majority of human coccidioidomycosis infections are asymptomatic or self-limited but may have sequestered spherules in highly structured granulomas. Under immunosuppression, reactivation of fungal growth can result in severe disease. B6D2F1 mice asymptomatically infected with C. posadasii strain 1038 were immunosuppressed with dexamethasone (DXM) in drinking water. Treated mice died 16−25 days later, while untreated mice survived (p < 0.001). Flow cytometry of lung granulomas on days 5, 10, 15, and 20 of DXM treatment showed immune cell populations decreased 0.5−1 log compared with untreated mice though neutrophils and CD19+IgD−IgM− cells rebounded by day 20. Histopathology demonstrated loss of granuloma structure by day 5 and increasing spherules through day 20. On day 20, T-cells were nearly absent and disorganized pyogranulomatous lesions included sheets of plasma cells and innumerable spherules. Mice given DXM for 14 days then stopped (DXM stop) survived 6 weeks (9/10). Lung fungal burdens were significantly lower (p = 0.0447) than mice that continued treatment (DXM cont) but higher than untreated mice. Histopathologically, DXM stop mice did not redevelop controlled granulomas by sacrifice, though T-cells were densely scattered throughout the lesions. This demonstrates a mouse model suitable for further study to understand the immunologic components responsible for maintenance control of coccidioidomycosis.

Cytologic appearance of hibernoma in two dogs.

Hibernomas are rare benign tumors of brown fat (adipose tissue) that have been reported in several different species. The cytologic characterization of these tumors has not been described in dogs. In this case report, we describe two dogs with hibernomas, focusing on the cytologic appearance of these unique neoplasms. Both cytologic specimens were highly cellular and predominated by vacuolated neoplastic cells with no evidence of concurrent inflammation. The cells contained a moderate to large number of variably sized cytoplasmic vacuoles, with occasional, irregularly shaped pink granular material. Most cells contained a single nucleus; however, cells displayed moderate anisokaryosis. A biopsy with histologic examination was performed in both cases, confirming the cytologic suspicion of hibernoma. Immunohistochemistry revealed that both tumors were positive for UCP1 and vimentin, and negative for cytokeratin. Hibernoma is an important differential diagnosis in dogs with conjunctival and periocular swellings that exfoliate numerous, mildly atypical, vacuolated cells.

Retrospective analysis of cutaneous lesions in 23 canine and 17 feline cases of coccidioidomycosis seen in Arizona, USA (2009-2015).

BACKGROUND: Coccidioidomycosis is a fungal disease caused by the dimorphic saprophytic fungus Coccidioides immitis or C. posadasii. Primary pulmonary infection can disseminate to cutaneous and subcutaneous tissues, or less commonly direct cutaneous inoculation may occur. HYPOTHESIS/OBJECTIVES: To characterize the historical, clinical, diagnostic and treatment findings in dogs and cats with cutaneous manifestation of coccidioidomycosis. ANIMALS: Twenty three dogs and seventeen cats diagnosed between 2009 and 2015 in Arizona, USA. METHODS: Retrospective review of medical records from dogs and cats from an endemic area with a confirmed diagnosis via histopathology, cytology and/or culture, and skin lesions. RESULTS: Age of affected dogs ranged from 14 weeks to 13 years (median = 7 years), whereas cats ranged from 3 to 17 years (median = 9 years). Subcutaneous nodules were the most common lesions in both species. Lesions were distributed widely and not often found over sites of bone infection. In 75% of dogs and 54.5% of cats with cutaneous lesions there were clinical signs of systemic illness, supporting the diagnosis of cutaneous disseminated disease. Four dogs and four cats had localized lesions with no systemic illness, consistent with possible primary cutaneous infection. The most common mode of diagnosis was cytology identification in both species. Fluconazole was the most commonly prescribed antifungal drug. CONCLUSIONS AND CLINICAL IMPORTANCE: Coccidioidomycosis is the most common mycosis of dogs and cats in endemic regions and cutaneous signs of the disease may be an initial presenting complaint. This study identified a variety of cutaneous manifestations of the disease in dogs and cats and should be recognized by clinicians.

Investigations of Salmonella enterica serovar newport infections of oysters by using immunohistochemistry and knockout mutagenesis.

The consumption of raw oysters is an important risk factor in the acquisition of food-borne disease, with Salmonella being one of a number of pathogens that have been found in market oysters. Previous work by our lab found that Salmonella was capable of surviving in oysters for over 2 months under laboratory conditions, and this study sought to further investigate Salmonella's tissue affinity and mechanism of persistence within the oysters. Immunohistochemistry was used to show that Salmonella was capable of breaching the epithelial barriers, infecting the deeper connective tissues of the oysters, and evading destruction by the oysters' phagocytic hemocytes. To further investigate the mechanism of these infections, genes vital to the function of Salmonella's two main type III secretion systems were disrupted and the survivability of these knockout mutants within oysters was assayed. When the Salmonella pathogenicity island 1 and 2 mutant strains were exposed to oysters, there were no detectable deficiencies in their abilities to survive, suggesting that Salmonella's long-term infection of oysters does not rely upon these two important pathogenicity islands and must be due to some other, currently unknown, mechanism.

Guidelines for resident training in veterinary clinical pathology. III: cytopathology and surgical pathology.

The Education Committee of the American Society for Veterinary Clinical Pathology has identified a need for improved structure and guidance of training residents in clinical pathology. This article is the third in a series of articles that address this need. The goals of this article are to describe learning objectives and competencies in knowledge, abilities, and skills in cytopathology and surgical pathology (CSP); provide options and ideas for training activities; and identify resources in veterinary CSP for faculty, training program coordinators, and residents. Guidelines were developed in consultation with Education Committee members and peer experts and with evaluation of the literature. The primary objectives of training in CSP are: (1) to develop a thorough, extensive, and relevant knowledge base of biomedical and clinical sciences applicable to the practice of CSP in domestic animals, laboratory animals, and other nondomestic animal species; (2) to be able to reason, think critically, investigate, use scientific evidence, and communicate effectively when making diagnoses and consulting and to improve and advance the practice of pathology; and (3) to acquire selected technical skills used in CSP and pathology laboratory management. These guidelines define expected competencies that will help ensure proficiency, leadership, and the advancement of knowledge in veterinary CSP and will provide a useful framework for didactic and clinical activities in resident-training programs.

Equine colitis X associated with infection by Clostridium difficile NAP1/027.

A 14-year-old Quarter Horse with a 48-hr history of colic was euthanized after failure to respond to treatment. At necropsy, cecal and colonic mucosae were congested throughout, and there was segmental edema and significant thickening of the intestinal wall. Excessive numbers of mononuclear cells were found in mucosal lamina propria. Submucosal hemorrhage was diffuse and extensive, and Clostridium difficile toxins A and B were detected. Large numbers of C. difficile were isolated, and genetic characterization revealed them to be North American pulsed-field gel electrophoresis type 1, polymerase chain reaction ribotype 027, and toxinotype III. Genes for the binary toxin were present, and toxin negative-regulator tcdC contained an 18-bp deletion. This genotype comprises the current human "epidemic strain," which is associated with human C. difficile-associated disease of greater than historical severity. The diagnosis was peracute typhlocolitis, with lesions and history typical of those attributed to colitis X.

Vaccine-induced cellular immune responses differ from innate responses in susceptible and resistant strains of mice infected with Coccidioides posadasii.

Susceptibility to Coccidioides spp. varies widely in humans and other mammals and also among individuals within a species. Among strains of mice with various susceptibilities, immunohistopathology revealed that C57BL/6 mice were highly susceptible to the disease following intranasal infection, DBA/2n mice were intermediate, and Swiss-Webster mice were innately resistant. Resistant Swiss-Webster mice developed prominent perivascular/peribronchiolar lymphocytic cuffing and well-formed granulomas with few fungal elements and debris in the necrotic center, surrounded by a mantle of macrophages, lymphocytes, and fibrocytes. Susceptible C57BL/6 mice became moribund between 14 and 18 days postinfection, with overwhelming numbers of neutrophils and spherules and very few T cells, the drastic reduction of which was associated with failure and death, while intermediate DBA/2n mice controlled the fungal burden but demonstrated progressive lung inflammation with prominent suppuration, and they deteriorated clinically. Vaccinated C57BL/6 mice had an early and robust lymphocyte response, which included significantly higher Mac2(+), CD3(+), and CD4(+) cell scores on day 18 than those of innately resistant SW mice and DBA/2n mice; they also had prominent perivascular/peribronchiolar lymphocytic infiltrates not present in their unvaccinated counterparts, and they appeared to be resolving lesions by day 56 compared to the other two strains, based on significantly lower disease scores and observably smaller and fewer lesions with few spherules and neutrophils.

Coccidioidomycosis in dogs and cats: a review.

The dimorphic fungi Coccidioides immitis and Coccidioides posadasii are the causative agents of coccidioidomycosis. Dogs and cats residing in and visiting endemic areas are at risk of exposure to infectious arthrospores. The primary infection is pulmonary and frequently results in chronic cough. Disseminated disease is common and causes cutaneous, osseous, cardiac, ocular, nervous system, or other organ disease. Radiographic changes include a variable degree of interstitial pulmonary infiltration, hilar lymphadenopathy, and osseous lesions. Serological titers support the diagnosis, but definitive diagnosis relies on identification of Coccidioides in cytological or tissue samples. Coccidioidomycosis should be considered in any dog or cat that has been potentially exposed during the previous 3 years and is presented with chronic illness, respiratory signs, lameness, lymphadenopathy, nonhealing cutaneous lesions, or neurological, ocular, or cardiac abnormalities.

Characterization of the MUC1.Tg/MIN transgenic mouse as a model for studying antigen-specific immunotherapy of adenomas.

A bigenic MUC1.Tg/MIN mouse model was developed by crossing Apc/(MIN/+) (MIN) mice with human MUC1 transgenic mice to evaluate MUC1 antigen-specific immunotherapy of intestinal adenomas. The MUC1.Tg/MIN mice developed adenomas at a rate comparable to that of MIN mice and had similar levels of serum MUC1 antigen. A MUC1-based vaccine consisting of MHC class I-restricted MUC1 peptides, a MHC class II-restricted pan-helper peptide, unmethylated CpG oligodeoxynucleotide and GM-CSF caused flattening of adenomas and significantly reduced the number of large adenomas. Immunization was successful in generating a MUC1-directed immune response evidenced by increased MUC1 peptide-specific anti-tumor cytotoxicity and IFN-gamma secretion by lymphocytes.

Maximizing the diagnostic value of cytology in small animal practice.

Cytology is a valuable diagnostic tool in veterinary medicine. A review of the literature indicates its utility in evaluation of specific lesions. The information obtained from cytology is greatly enhanced by a good understanding of its advantages and disadvantages and an open and interactive relationship between clinicians and pathologists. Critical selection of appropriate lesions, good sampling technique, quality sample handling, and provision of a complete clinical history and lesion description enhance the utility of the information returned to the clinician by the pathologist. A good cytologic diagnosis is a team effort.

Fungal diagnostics: current techniques and future trends.

The diagnosis of fungal disease is a challenge that requires diligent attention to history and clinical signs as well as an astute ability to interpret laboratory data. Because fungal disease can mimic other infectious and neoplastic diseases in clinical presentation, the clinician has to be aware of fungal diseases common locally as well as in other regions of the country. A global approach to the diagnosis of fungal disease that correlates clinical signs as well as physical examination, clinical pathology, and histopathology findings with serology, culture, and the newer immunohistochemical and molecular techniques, where available, is the best approach to optimize the identification of the underlying agent.

Coccidioidomycosis: a diagnostic challenge.

Coccidioidomycosis is a systemic fungal infection acquired endemically in the southwestern United States. Clinical disease is quite common in the dog; though less frequently recognized in the cat, disease is often severe at the time of diagnosis. Diagnosis can be a challenge because serology, while specific, is not very sensitive and quantitative titration of antibodies does not correlate entirely with clinical disease in dogs. Radiographs, serum biochemistry tests and complete blood counts are beneficial additions to the database when establishing a diagnosis; cytology, histopathology, and culture are definitive when available. Advanced imaging can detect central nervous system and subtle skeletal lesions. Disease can occur in most organs of the body and may prove a diagnostic challenge requiring several modalities. Coccidioidomycosis may need to be considered both in animals in the endemic region and in those with a travel history through it.

Cellular immune suppressor activity resides in lymphocyte cell clusters adjacent to granulomata in human coccidioidomycosis.

The in situ immunologic response in human coccidioidomycosis remains undefined. To explore this further, pulmonary necrotizing coccidioidal granulomata were examined using immunohistochemical staining for lymphocyte subsets and for the cytokines interleukin-10 (IL-10) and gamma interferon (IFN-gamma). Discrete perigranulomatous lymphocytic clusters were seen in eight of nine tissues examined. In these tissues, T lymphocytes (CD3+) significantly outnumbered B lymphocytes (CD20+) in the mantle area of the granulomata (P = 0.028), whereas the clusters were composed of roughly equal numbers of T and B lymphocytes. While the number of cells in the mantle expressing IL-10 was similar to those in the perigranulomatous clusters, there were significantly more cells expressing IFN-gamma in the mantle than in the clusters (P = 0.037). Confocal microscopy revealed that CD4+ T lymphocytes and B lymphocytes are associated with IL-10 production. CD4+CD25+ T lymphocytes were identified in the perigranulomatous clusters but were not associated with IL-10 production. This is the first report noting perigranulomatous lymphocyte clusters and IL-10 in association with human coccidioidal granulomata and suggests that down-regulation of the cellular immune response is occurring within coccidioidal granulomata.

Incidence of coccidioides infection among dogs residing in a region in which the organism is endemic.

OBJECTIVE: To determine the incidence of Coccidioides infection among dogs residing in a region in which the organism is endemic (Pima and Maricopa counties, Arizona) and estimate the rate of clinical illness. DESIGN: Community-based longitudinal and cross-sectional studies. ANIMALS: 124 healthy 4- to 6-month-old seronegative puppies (longitudinal study) and 381 4- to 18-month-old dogs with unknown serostatus (cross-sectional study). PROCEDURE: Dogs in the longitudinal study were tested at 6-month intervals for at least 1 year for anticoccidioidal antibodies. Dogs that became ill were evaluated for coccidioidomycosis. Dogs in the cross-sectional study were tested for anticoccidioidal antibodies once, and clinical abnormalities were recorded. RESULTS: 28 of the 104 (27%) dogs that completed the longitudinal study developed anticoccidioidal antibodies. Thirty-two of the 381 (8%) dogs in the cross-sectional study had anticoccidioidal antibodies. Five seropositive dogs in the longitudinal study and 13 seropositive dogs in the cross-sectional study had clinical signs of disease. The remaining seropositive dogs were otherwise healthy and were classified as subclinically infected. Survival analysis indicated that the cumulative probability of infection by 2 years of age was 28%, and the cumulative probability of clinical infection by 2 years of age was 6%. Titers for clinically and subclinically infected dogs overlapped. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that young dogs living in the study area had a high likelihood of becoming infected with Coccidioides spp, but few developed clinical illness. Serologic testing alone was insufficient for a diagnosis of clinical disease because of the overlap in titers between clinically and subclinically infected dogs.

Risk factors associated with Coccidioides infection in dogs.

OBJECTIVE: To evaluate potential risk factors for Coccidioides infection among dogs living in a region in which the organism is endemic (Pima and Maricopa counties, Arizona). DESIGN: Community-based longitudinal and cross-sectional studies. ANIMALS: 104 healthy 4- to 6-month-old puppies (longitudinal study) and 381 4- to 18-month-old dogs with unknown serostatus (cross-sectional study). PROCEDURE: Dogs in the longitudinal study were tested 3 times at 6-month intervals for anticoccidioidal antibodies; dogs in the cross-sectional study were tested only once. Owners of all dogs completed a questionnaire on potential environmental exposures. RESULTS: In the longitudinal study, the relative risk of infection for dogs that were outdoors during the day was 4.9 times the risk for dogs that were kept indoors. Seropositive dogs in the cross-sectional study were 6.2 times as likely to have access to > 1 acre to roam as were seronegative dogs. Logistic regression analysis indicated that the odds of infection increased with age (odds ratio [OR], 1.1), amount of roaming space (OR, 2.4), and walking in the desert (OR, 2.2). Walking on sidewalks had a protective effect (OR, 0.4). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in regions in which the organism is endemic, dogs that spend more time outdoors or have more land in which to roam are at greater risk of infection with Coccidioides spp.

Chemo-immunotherapy of breast cancer using vesiculated alpha-tocopheryl succinate in combination with dendritic cell vaccination.

In this study, we evaluated the efficacy of vesiculated alpha-tocopheryl succinate (Valpha-TOS) in combination with non-antigen pulsed, nonmatured dendritic cells (nmDC) to treat pre-established tumors of the highly metastatic murine mammary cancer cell line 4T1. We demonstrated that Valpha-TOS in combination with non-antigen pulsed nmDC significantly inhibits the growth of established tumors in vivo and prolongs survival of treated mice. In addition, when initiated after resection of the established primary tumor, the combination treatment dramatically inhibits residual metastatic disease. The clinical response achieved with the combination therapy was correlated with increased interferon-gamma and interleukin-4 (IL-4) production by splenic lymphocytes and draining lymph node cells. Interestingly, when used in combination with Valpha-TOS, nmDC were as effective as tumor necrosis factor-alpha matured DC at inhibiting the growth of pre-established tumors. Valpha-TOS-induced cellular factors collected by high-speed centrifugation of supernatant from Valpha-TOS-treated tumor cells caused maturation of DC as evidenced by the up-regulation of co-stimulatory molecules and secretion of IL-12p70. These results demonstrate the potential usefulness of Valpha-TOS + DC chemo-immunotherapy in treating established primary mammary tumors as well as residual metastatic disease.

Quaternary Ammonium-Induced Cutaneous and Gastrointestinal Mucosal Lesions in a Dog.

A dog developed severe ulcerative dermatitis and upper gastrointestinal mucosal ulceration after accidental exposure to a concentrated quaternary ammonium disinfectant solution. Secondary problems included dyspnea and cholestasis. Prolonged intensive care was required and included gastrostomy tube placement via endoscopy, extensive wound care, and systemic antibiotics. In contrast to earlier reports and although the offending compound was in higher concentration, contact irritation was much more severe yet no overt systemic toxic effects were noted. This case illustrates the great caution that must be exercised when handling commonly employed laboratory germicides.