Dengue viral antigens have been demonstrated in several types of naturally infected human tissues, but little is known of whether these same tissues have detectable viral RNA. We studied tissue specimens from patients with serologically or virologically confirmed dengue infections by immunohistochemistry (IHC) and in situ hybridization (ISH), to localize viral antigen and RNA, respectively. IHC was performed on specimens obtained from 5 autopsies and 24 biopsies and on 20 blood-clot samples. For ISH, antisense riboprobes to the dengue E gene were applied to tissue specimens in which IHC was positive. Viral antigens were demonstrated in Kupffer and sinusoidal endothelial cells of the liver; macrophages, multinucleated cells, and reactive lymphoid cells in the spleen; macrophages and vascular endothelium in the lung; kidney tubules; and monocytes and lymphocytes in blood-clot samples. Positive-strand viral RNA was detected in the same IHC-positive cells found in the spleen and blood-clot samples. The strong, positive ISH signal in these cells indicated a high copy number of viral RNA, suggesting replication.
Disease manifestation, pathology, and tissue tropism following infection with Tioman virus (TioPV), a newly isolated, bat-derived paramyxovirus, was investigated in subcutaneously (n = 12) and oronasally (n = 4) inoculated pigs. Pigs were either asymptomatic or developed pyrexia, but all of the animals produced neutralizing antibodies. The virus (viral antigen and/or genome) was detected in lymphocytes of the thymus, tonsils, spleen, lymph nodes and Peyer's patches (ileum), tonsillar epithelium, and thymic epithelioreticular cells. Virus was isolated from oral swabs but not from urine. Our findings suggest that the pig could act as an intermediate or amplifying host for TioPV and that oral secretion is a possible means of viral transmission.
Cytomegalovirus (CMV) congenital infection is the major viral cause of well-documented birth defects in human. Because CMV is species-specific, the main obstacle to developing animal models for congenital infection is the difference in placental architecture, which preludes virus transmission across the placenta. The rat placenta, resembling histologically to that of human, could therefore facilitate the study of CMV congenital infection in human.
The present study described the kinetics of Rat cytomegalovirus (RCMV) infection in newborn rats by monitoring infectious virus and viral antigens in various organs, viral DNA in the blood (DNAemia) and antibody response. These parameters were evaluated quantitatively using double-antibody sandwich ELISA (DAS-ELISA), real-time PCR, indirect ELISA and virus infectivity assay. For the first time DAS-ELISA was used for detection of RCMV antigen directly from organ samples. The relationships between the presence of viral antigens in the infected organs and antibody levels were established by the Spearman's rank test. It was found that the virus was present in the blood, spleen, liver, lungs, and kidneys earlier than in the salivary glands. Furthermore, the early immunity of the newborn rats led to a delayed seroconversion. We suggested that the prolonged presence of the virus in salivary glands could augment the antibody response that conversely might be responsible for a reduction of viremia. This study expanded our understanding of RCMV pathogenesis leading to improved therapeutic and preventive treatment regimens particularly for the neonatal Human cytomegalovirus (HCMV) infections. Additionally, the detection procedures developed in this study such as DAS-ELISA and real-time PCR could serve as alternative techniques for rapid screening of large number of samples.
Newcastle disease (ND) is a highly contagious avian disease and one of the major causes of economic losses in the poultry industry. The emergence of virulent NDV genotypes and repeated outbreaks of NDV in vaccinated chickens have raised the need for fundamental studies on the virus-host interactions. In this study, the profiles of B and T lymphocytes and macrophages and differential expression of 26 immune-related genes in the spleen of specific-pathogen-free (SPF) chickens, infected with either the velogenic genotype VII NDV strain IBS002 or the genotype VIII NDV strain AF2240, were evaluated. A significant reduction in T lymphocyte population and an increase in the infiltration of IgM+ B cells and KUL01+ macrophages were detected in the infected spleens at 1, 3 and 4 days post-infection (dpi) (P<0.05). The gene expression profiles showed an up-regulation of CCLi3, CXCLi1, CXCLi2 (IL-8), IFN-γ, IL-12α, IL-18, IL-1β, IL-6, iNOS, TLR7, MHCI, IL-17F and TNFSF13B (P<0.05). However, these two genotypes showed different cytokine expression patterns and viral load. IBS002 showed higher viral load than AF2240 in spleen at 3 and 4dpi and caused a more rapid up-regulation of CXCLi2, IFN-γ, IL-12α, IL-18, IL-1β, iNOS and IL-10 at 3dpi. Meanwhile, the expression levels of CCLI3, CXCLi1, IFN-γ, IL-12α, IL-1β and iNOS genes were significantly higher in AF2240 at 4dpi. In addition, the expression levels of IL-10 were significantly higher in the IBS002-infected chickens at 3 and 4dpi. Hence, infection with velogenic genotype VII and VIII NDV induced different viral load and production of cytokines and chemokines associated with inflammatory reactions.
Boid inclusion body disease (BIBD) is a viral disease of boid snakes believed to be caused by reptarenavirus belonging to the family Arenaviridae. Unlike most mammalian arenaviruses, the reservoir host for reptarenavirus is still unknown. In this study, the pathological responses were evaluated in a mouse model for a period of 28 days. Blood and tissue samples (lung, liver, spleen, heart, kidney and brain) were collected for evaluation of hematology, biochemistry, histopathology and oxidative enzyme levels at six time points (1, 3, 7, 14, 21 and 28 days), after viral infection (2.0 × 10(6) pfu/mL) in the infected and normal saline in the control groups. An initial increase (p spleen, brain and lungs were mainly associated with degeneration, necrosis and infiltration of lymphocytes. Viral counts were low on days 7 and 14 but surged in both the liver and spleen on day 21 and 28. This study has shown that reptarenavirus replicates in mammalian host and induces oxidative stress. Furthermore, the resultant hematobiochemical and histopathological changes observed in infected mice were similar to what has been reported in mammarenavirus infections. This suggests that rodents may serve as potential reservoir hosts for reptarenavirus.
This study evaluates the immune responses of single avian influenza virus (AIV) HA DNA vaccine immunization using attenuated Salmonella enterica sv. Typhimurium as an oral vaccine carrier and intramuscular (IM) DNA injection. One-day-old specific-pathogen-free (SPF) chicks immunized once by oral gavage with 10(9) Salmonella colony-forming units containing plasmid expression vector encoding the HA gene of A/Ck/Malaysia/5858/04 (H5N1) (pcDNA3.1.H5) did not show any clinical manifestations. Serum hemagglutination inhibition (HI) titer samples collected from the IM immunized chickens were low compared to those immunized with S. typhimurium.pcDNA3.1.H5. The highest average antibody titers were detected on day 35 post immunization for both IM and S. typhimurium.pcDNA3.1.H5 immunized groups, at 4.0±2.8 and 51.2±7.5, respectively. S. typhimurium.pcDNA3.1.H5 also elicited both CD4(+) and CD8(+) T cells from peripheral blood mononuclear cells (PBMCs) of immunized chickens as early as day 14 after immunization, at 20.5±2.0 and 22.9±1.9%, respectively. Meanwhile, the CD4(+) and CD8(+) T cells in chickens vaccinated intramuscularly were low at 5.9±0.9 and 8.5±1.3%, respectively. Immunization of chickens with S. typhimurium.pcDNA3.1.H5 enhanced IL-1β, IL-12β, IL-15 and IL-18 expressions in spleen although no significant differences were recorded in chickens vaccinated via IM and orally with S. typhimurium and S. typhimurium.pcDNA3.1. Hence, single oral administrations of the attenuated S. typhimurium containing pcDNA3.1.H5 showed antibody, T cell and Th1-like cytokine responses against AIV in chickens. Whether the T cell response induced by vaccination is virus-specific and whether vaccination protects against AIV infection requires further study.