Detection and phylogenetic analysis of Orf virus from sheep in Brazil: a case report

<p>Abstract</p> <p>Background</p> <p><it>Orf virus </it>(ORFV), the prototype of the genus <it>Parapoxvirus </it>(PPV), is the etiological agent of contagious ecthyma, a severe exanthematic dermatitis that afflicts domestic and wild small ruminants. Although South American ORFV outbreaks have occurred and diagnosed there are no South American PPV major membrane glycoprotein B2L gene nucleotide sequences available.</p> <p>Case presentation</p> <p>an outbreak of ovine contagious ecthyma in Midwest Brazil was investigated. The diagnosis was based on clinical examinations and molecular biology techniques. The molecular characterization of the virus was done using PCR amplification, cloning and DNA sequencing of the B2L gene. The phylogenetic analysis demonstrated a high degree of identity with ORFV strains, and the isolate was closest to the ORFV-India 82/04 isolate. Another Brazilian ORFV isolate, NE1, was sequenced for comparative analysis and also showed a high degree of identity with an Asian ORFV strain.</p> <p>Conclusion</p> <p>Distinct ORFV strains are circulating in Brazil. This is the first report on the phylogenetic analysis of an ORFV in South America.</p

A tetravalent dengue nanoparticle stimulates antibody production in mice

<p>Abstract</p> <p>Background</p> <p>Dengue is a major public health problem worldwide, especially in the tropical and subtropical regions of the world. Infection with a single <it>Dengue virus </it>(DENV) serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients experiencing secondary infection with a different serotype progresses to the severe form of the disease, dengue hemorrhagic fever/dengue shock syndrome. Currently, there are no licensed vaccines or antiviral drugs to prevent or treat dengue infections. Biodegradable nanoparticles coated with proteins represent a promising method for in vivo delivery of vaccines.</p> <p>Findings</p> <p>Here, we used a murine model to evaluate the IgG production after administration of inactivated DENV corresponding to all four serotypes adsorbed to bovine serum albumin nanoparticles. This formulation induced a production of anti-DENV IgG antibodies (p < 0.001). However, plaque reduction neutralization assays with the four DENV serotypes revealed that these antibodies have no neutralizing activity in the dilutions tested.</p> <p>Conclusions</p> <p>Our results show that while the nanoparticle system induces humoral responses against DENV, further investigation with different DENV antigens will be required to improve immunogenicity, epitope specicity, and functional activity to make this platform a viable option for DENV vaccines.</p

Microscopic Analysis of the Tupanvirus Cycle in Vermamoeba vermiformis

Since Acanthamoeba polyphaga mimivirus (APMV) was identified in 2003, several other giant viruses of amoebae have been isolated, highlighting the uniqueness of this group. In this context, the tupanviruses were recently isolated from extreme environments in Brazil, presenting virions with an outstanding tailed structure and genomes containing the most complete set of translation genes of the virosphere. Unlike other giant viruses of amoebae, tupanviruses present a broad host range, being able to replicate not only in Acanthamoeba sp. but also in other amoebae, such as Vermamoeba vermiformis, a widespread, free-living organism. Although the Tupanvirus cycle in A. castellanii has been analyzed, there are no studies concerning the replication of tupanviruses in other host cells. Here, we present an in-depth microscopic study of the replication cycle of Tupanvirus in V. vermiformis. Our results reveal that Tupanvirus can enter V. vermiformis and generate new particles with similar morphology to when infecting A. castellanii cells. Tupanvirus establishes a well-delimited electron-dense viral factory in V. vermiformis, surrounded by lamellar structures, which appears different when compared with different A. castellanii cells. Moreover, viral morphogenesis occurs entirely in the host cytoplasm within the viral factory, from where complete particles, including the capsid and tail, are sprouted. Some of these particles have larger tails, which we named “supertupans.” Finally, we observed the formation of defective particles, presenting abnormalities of the tail and/or capsid. Taken together, the data presented here contribute to a better understanding of the biology of tupanviruses in previously unexplored host cells

Nested-multiplex PCR detection of Orthopoxvirus and Parapoxvirus directly from exanthematic clinical samples

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Dengue Virus 3 Genotype I in Aedes aegypti Mosquitoes and Eggs, Brazil, 2005–2006

Dengue virus type 3 genotype I was detected in Brazil during epidemics in 2002–2004. To confirm this finding, we identified this virus genotype in naturally infected field-caught Aedes aegypti mosquitoes and eggs. Results showed usefulness of virus investigations in vectors as a component of active epidemiologic surveillance

Intracerebral infection with dengue-3 virus induces meningoencephalitis and behavioral changes that precede lethality in mice

<p>Abstract</p> <p>Background</p> <p>Dengue, one of the most important arboviral diseases of humans, may cause severe systemic disease. Although dengue virus (DENV) has been considered to be a non-neurotropic virus, dengue infection has been associated recently with a series of neurological syndromes, including encephalitis. In this work, we evaluated behavioral changes and inflammatory parameters in C57BL/6 mice infected with non-adapted dengue virus 3 (DENV-3) genotype I.</p> <p>Methods</p> <p>C57BL/6 mice received 4 × 10³PFU of DENV-3 by an intracranial route. We evaluated the trafficking of leukocytes in brain microvasculature using intravital microscopy, and evaluated chemokine and cytokine profiling by an ELISA test at 3 and 6 days post infection (p.i.). Furthermore, we determined myeloperoxidase activity and immune cell populations, and also performed histopathological analysis and immunostaining for the virus in brain tissue.</p> <p>Results</p> <p>All animals developed signs of encephalitis and died by day 8 p.i. Motor behavior and muscle tone and strength parameters declined at day 7 p.i. We observed increased leukocyte rolling and adhesion in brain microvasculature of infected mice at days 3 and 6 p.i. The infection was followed by significant increases in IFN-γ, TNF-α, CCL2, CCL5, CXCL1, and CXCL2. Histological analysis showed evidence of meningoencephalitis and reactive gliosis. Increased numbers of neutrophils, CD4⁺and CD8⁺T cells were detected in brain of infected animals, notably at day 6 p.i. Cells immunoreactive for anti-NS-3 were visualized throughout the brain.</p> <p>Conclusion</p> <p>Intracerebral infection with non-adapted DENV-3 induces encephalitis and behavioral changes that precede lethality in mice.</p

Passatempo Virus, a Vaccinia Virus Strain, Brazil

Passatempo virus was isolated during a zoonotic outbreak. Biologic features and molecular characterization of hemagglutinin, thymidine kinase, and vaccinia growth factor genes suggested a vaccinia virus infection, which strengthens the idea of the reemergence and circulation of vaccinia virus in Brazil. Molecular polymorphisms indicated that Passatempo virus is a different isolate

Brazilian Vaccinia Viruses and Their Origins

Genetic diversity enables this virus to persist in Brazil and other parts of the world