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Acquired T cell immunity is central for protection against infection. However, the immunological consequences of exposing memory T cells to high Ag loads during acute and persistent infection with systemic pathogens are poorly understood. We investigated this by using infection with Anaplasma marginale, a ruminant pathogen that replicates to levels of 10(9)(More)
Antigen-specific CD4+ T cells play a critical role in protective immunity to many infectious pathogens. Although the antigen-specific CD4+ T cells can be measured by functional assays such as proliferation or cytokine enzyme-linked immunospot, such assays are limited to a specific function and cannot quantify anergic or suppressed T cells. In contrast,(More)
Control of blood-borne infections is dependent on antigen-specific effector and memory T cells and high-affinity IgG responses. In chronic infections characterized by a high antigen load, it has been shown that antigen-specific T and B cells are vulnerable to downregulation and apoptosis. Anaplasma marginale is a persistent infection of cattle characterized(More)
We have shown that in cattle previously immunized with outer membrane proteins, infection with Anaplasma marginale induces a functionally exhausted CD4 T-cell response to the A. marginale immunogen. Furthermore, T-cell responses following infection in nonimmunized cattle had a delayed onset and were sporadic and transient during persistent infection. The(More)
Reports of free-ranging Roosevelt elk (Cervus elaphus roosevelti) with abnormal hooves and lameness increased significantly in southwestern Washington, USA, during winter 2008. In March 2009 we examined five severely affected elk with clinical lameness from this region to characterize hoof lesions, examine the general health of affected elk, and potentially(More)
Epizootic hemorrhagic disease virus (EHDV) infection was diagnosed in a 3-year-old yak. The yak had signs of intermittent tremors, dysphagia, oral ulcerative lesions, hemorrhagic enteritis, tachypnea, and thrombocytopenia. Postmortem diagnostics confirmed EHDV (serotype 2) using reverse-transcriptase polymerase chain reaction (RT-PCR). Gross and(More)
Lobomycosis (lacaziosis) is a chronic, granulomatous, fungal infection of the skin and subcutaneous tissues of humans and dolphins. To date, the causative agent, the yeast-like organism Lacazia loboi, has not been grown in the laboratory, and there have been no recent reports describing attempts to culture the organism. As a result, studies on the efficacy(More)
An 8-yr-old female slender-tailed meerkat (Suricata suricatta) presented with a necrotic sublingual mass and osteolysis of the mandible. After 1 mo of palliative care, the meerkat was euthanized. The mass was diagnosed histologically as an anaplastic carcinoma with extensive rostral mandibular destruction. Immunohistochemistry for vimentin and cytokeratin(More)
A 31-yr-old male Sumatran orangutan (Pongo abelii) presented with 14 yr of chronic purulent nasal drainage and cough with intermittent exacerbation of symptoms requiring systemic antibiotic treatment. He was diagnosed with a cystic fibrosis (CF)-like condition. Evaluation consisted of bronchoscopy with bronchoalveolar lavage, culture, and computed(More)
A 3-year-old neutered male Australian Shepherd mix dog presented with metastatic soft tissue sarcoma arising from a primary tumor in the left lumbar fascia. Two separate metastases to the lungs were characterized by neoplasia within bronchiolar walls, which caused obstruction of the bronchiolar lumina and atelectasis of adjacent alveoli, a characteristic(More)