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Porcine torque teno sus virus (TTSuV) has been suggested as a co-factor for the development of porcine circovirus-associated diseases. However, the pathogenic role of TTSuV is still inconclusive, and the target cell and tissue tropism of this virus are also ambiguous. In the present study, a multi-strained pooled probe-based in situ hybridization was established to detect the nucleic acids of TTSuV1 and TTSuV2 in the tissue. The strategy of using polymerase chain reaction-derived digoxigenin-labeled multi-strained pooled probe, instead of single-strained probe or oligonucleotide, was to overcome the fact of high sequence diversity among TTSuV strains and simultaneous infection with distinct strains of TTSuV in the same animal. The cell tropism and tissue distribution were evaluated by grading system with tissues from major organs. Lymphoid tissues, including superficial inguinal, mesenteric, and hilar lymph nodes, tonsil, intestinal lamina propria of mucosa and Peyer's patches, and sometimes spleen, generally contained higher levels of positive signals and are considered as the target sites for TTSuV. Morphologically, the distribution of TTSuV-positive signals had a strong correlation with the T lymphocyte zone. T lymphocytes are, thus, speculated as the major target cells for TTSuV., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Torque teno sus virus type 1 (TTSuV1) ORF1 is considered to encode the viral capsid (Cap) protein, which is crucial for the induction of TTSuV1-specific antibodies and protective immunity in the host. Eight monoclonal antibodies (mAbs) directed against the Cap protein were generated and biologically characterized. The immunoreactivity of the Cap protein expressed in transfected 293T cells for these mAbs was determined with an immunoperoxidase monolayer assay. The antigen epitopes of the Cap protein were mapped using these mAbs and truncated Cap proteins expressed in Escherichia coli. Fine epitope mapping was then performed with a panel of synthesized polypeptides. All the mAbs reacted with the Cap protein C fragment expressed in E. coli. One antigenic epitope of the Cap protein, which reacted with seven mAbs, had the polypeptide sequence (536)HPKYAGQGGGYTT(548), whereas another epitope recognized by the 1E9 mAb had the polypeptide sequence (549)EIGHQGITAASLR(561). It is interesting that the two new epitopes are adjacent, but mutually independent. This study should facilitate further investigation of the antigenic differences and enable the differential diagnosis of the virus., (Copyright © 2013 Elsevier B.V. All rights reserved.)

In late 2005, a postweaning, high mortality syndrome spread rapidly through finishing barns in swine dense areas of the United States. Diagnostic investigations consistently detected porcine circovirus type 2 (PCV2) from diseased tissues. Subsequent genetic analysis revealed that the infectious agent was a PCV2 type termed "PCV2b". Prior to late 2004, only the PCV2a type, but not PCV2b, had been reported in North America. In this communication, we produce severe postweaning multisystemic wasting syndrome (PMWS) in gnotobiotic pigs using infectious PCV2a and PCV2b generated from DNA clones constructed from field isolates identified in the 2005 outbreak. Clinical signs exhibited by diseased pigs included anorexia, dyspnea and listlessness. Mortality was typically observed within 12h of onset of dyspnea. The most striking microscopic lesions in affected animals were severe hepatic necrosis and depletion of germinal centers in lymph nodes with associated abundant PCV2 viral antigen. Clinical signs and lesions observed in these studies were comparable to those reported in experiments with gnotobiotic pigs inoculated with a PCV2a isolate while concurrently receiving immune-stimulation or co-infection with porcine parvovirus or torque teno virus. The animals in these studies were confirmed to be free of detectable porcine parvovirus, porcine reproductive and respiratory syndrome virus, bovine viral diarrhea virus, swine hepatitis E virus, and aerobic and anaerobic bacteria. Seven out of 24 PCV2 inoculated pigs had a detectable congenital torque teno virus infection with no correlation to clinical disease. Thus, in these studies, both PCV2a and PCV2b isolates were singularly capable of inducing high mortality in the absence of any detectable infectious co-factor., (Published by Elsevier B.V.)

Iridoviruses, pathogens typically associated with fish and amphibians, have recently been shown to cause acute respiratory disease in chelonians including box turtles, red-eared sliders, gopher tortoises, and Burmese star tortoises. Case reports of natural infections in several chelonian species in the United States have been reported, however the prevalence remains unknown in susceptible populations of free-ranging chelonians. To determine the prevalence of iridovirus exposure in free-ranging gopher tortoises (Gopherus polyphemus) in the southeast United States, an indirect enzyme-linked immunosorbent assay (ELISA) was developed and used to evaluate plasma samples from wild gopher tortoises (G. polyphemus) from: Alabama (n=9); Florida (n=658); Georgia (n=225); Louisiana (n=12); Mississippi (n=28); and unknown locations (68) collected between 2001 and 2006. Eight (1.2%) seropositive tortoises were identified from Florida and seven (3.1%) from Georgia for an overall prevalence of 1.5%. Additionally, a population of eastern box turtles was sampled from a private nature sanctuary in Pennsylvania that experienced an outbreak of iridovirus the previous year, which killed 16 turtles. Only 1 turtle out of 55 survivors tested positive (1.8%). Results suggest a low exposure rate in chelonians to this pathogen; however, it is suspected that this is an underestimate of the true prevalence. Since experimental transmission studies and past outbreaks have shown a high rate of mortality in infected turtles, turtles may die before they develop an antibody response. Further, the duration of the antibody response is unknown and may also cause an underestimate of the true prevalence., (Copyright 2009 Elsevier B.V. All rights reserved.)

An immunoblot technique for the detection of lymphocystis disease virus (LCDV) in naturally infected gilt-head seabream (Sparus aurata, L.) has been developed. A specific antiserum against a 60 kDa viral protein has been proven to be an appropriate tool for LCDV diagnosis either from inoculated cell cultures or from fish tissues using the immunoblot assay. The sensitivity of this technique varied between 10(-1) and 10(2) TCID50. LCDV has also been detected in fish tissues from both, diseased and asymptomatic gilt-head seabream. For the asymptomatic fish detection, a viral amplification step in cell culture and a subsequent viral concentration using polyethylene glycol (PEG) (600 wt) are required. On the contrary, immunoblot allowed the detection of LCDV antigens directly from tissue homogenates of diseased fish. The method described in this study shows higher sensitivity than classical detection techniques based on cell culture inoculation.