ULTRASOUND LOCALIZATION AND GUIDANCE FOR RENAL BIOPSY IN THE HORSE

Real-time ultrasonography was used to assist percutaneous renal biopsies in seven normal horses. Ultrasound (US) guidance and blind biopsy following US localization were compared. Ten biopsies (seven right kidney and three left kidney) were performed. A transverse approach to the lateral border of the right kidney through the 17th intercostal space was favored, with the needle angle being approximately perpendicular to the body wall. Both biopsy techniques were effective, but blind biopsy following US localization was favored as it was easily performed by one operator without the need for specialized biopsy equipment. The spleen had a variable location and its penetration with the biopsy needle was necessary to obtain two left kidney biopsies. Macroscopic and microscopic hematuria was observed postbiopsy in one and four horses, respectively, out of six horses examined. Perirenal hemorrhage was a prominent finding on necropsy in five of six horses euthanized.     

Dynamics of viral spread in bluetongue virus infected calves

The kinetics of viremia and sites of viral replication in bluetongue virus (BTV) infected calves were characterized by virus isolation, serology and immunofluorescence staining procedures. In addition, the role of the regional lymph node and lymphatics draining inoculated skin in the pathogenesis of BTV infection was determined by analyzing efferent lymph collected from indwelling cannulas. Viremia persisted for 35 to 42 days after inoculation (DAI) and virus co-circulated with neutralizing antibodies for 23 to 26 days. Virus was first isolated from peripheral blood mononuclear (PBM) cells at 3 DAI, after stimulation of PBM cells with interleukin 2 and mitogen. BTV was frequently isolated from erythrocytes, platelets and stimulated PBM cells but never from granulocytes and rarely from plasma during viremia. Virus was consistently isolated from erythrocytes late in the course of veremia. Interruption of efferent lymph flow by cannulation delayed the onset of viremia to 7 DAI. BTV was infrequently isolated from lymph cells, and few fluorescence positive cells were observed after lymph and PBM cells were labelled with a BTV-specific monoclonal antibody. Virus was isolated from spleen by 4 DAI and most tissues by 6 DAI, whereas virus was isolated from bone marrow only at 10 DAI. Virus was not isolated from any tissue after termination of viremia. It is concluded that primary viral replication occurred in the local lymph node and BTV then was transported in low titer to secondary sites of replication via infected lymph and PBM cells. We speculate that virus replication in spleen resulted in release of virus into the circulation and non-selective infection of blood cells which disseminated BTV to other tissues. Virus association with erythrocytes likely was responsible for prolonged viremia, although infected erythrocytes eventually were cleared from the circulation and persistent BTV infection of calves did not occur.     

Plasmacytoid dendritic cell depletion leads to an enhanced mononuclear phagocyte response in lungs of mice with lethal influenza virus infection

Plasmacytoid dendritic cells (pDCs) have been implicated both in the control and pathogenesis of influenza virus infection. We demonstrate that pDC depletion has marked effects on the response of mononuclear phagocytes, including conventional DCs (cDCs) and macrophages, to lethal influenza virus infection. Infection of mice lacking pDCs through antibody-mediated depletion resulted in substantially increased accumulation of mononuclear phagocytes and their progenitors in lungs compared to non-treated controls. pDC ablation resulted in a 5- to 35-fold enhancement of intracellular TNF-α and IL-6 production from inflammatory cDCs and exudate macrophages. Purified pulmonary cDCs and macrophages cultured from pDC-depleted mice produced significantly elevated levels of pro-inflammatory cytokines and chemokines compared to pDC-intact counterparts. Elimination of pDCs resulted in decreased lung IFN-α production and an immediate and transient reduction in lung virus burden but did not impact disease outcome. These data reveal a suppressive effect of pDCs on the inflammatory response to influenza virus infection in the lung.     

Streptococcus equi infection as a cause of panophthalmitis in a horse

Streptococcus equi was isolated from a corneal ulcer in a horse. The ulcer developed as an extension of septic uveitis subsequent to submandibular lymphadenopathy. The condition was refractory to therapy and panophthalmitis ensued. The affected eye was enucleated and S. equi was isolated in pure culture from the anterior chamber. S. equi should be considered as an etiologic agent in cases of uveitis in the horse, especially if there is a recent history of strangles.