Preliminary Classification of Novel Hemorrhagic Fever-Causing Viruses Using Sequence-Based PAirwise Sequence Comparison (PASC) Analysis.

During the last decade, genome sequence-based classification of viruses has become increasingly prominent. Viruses can be even classified based on coding-complete genome sequence data alone. Nevertheless, classification remains arduous as experts are required to establish phylogenetic trees to depict the evolutionary relationships of such sequences for preliminary taxonomic placement. Pairwise sequence comparison (PASC) of genomes is one of several novel methods for establishing relationships among viruses. This method, provided by the US National Center for Biotechnology Information as an open-access tool, circumvents phylogenetics, and yet PASC results are often in agreement with those of phylogenetic analyses. Computationally inexpensive, PASC can be easily performed by non-taxonomists. Here we describe how to use the PASC tool for the preliminary classification of novel viral hemorrhagic fever-causing viruses.

[Viral hemorrhagic fever as a biological weapon].

The viruses that cause hemorrhagic fever belong to four virus families: the Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae. These viruses are candidates for biological warfare agents because they are stable when aerosolized and cause severe debilitating disease. Research and development regarding the use of these viruses as warfare agents has been performed in the former Soviet Union and other countries. The introduction of these agents into non endemic countries poses a major public health threat to that country. Israel is not endemic for these agents, and therefore, local infection can occur from a traveller (human or animal) from an endemic country or due to intentional dissemination. Major clinical manifestations of hemorrhagic fevers are that of fever, rash, malaise and hemorrhagic signs. Due to the similarity between syndromes, any person with a history of persistent fever and any sign of hemorrhage should be considered as having viral hemorrhagic fever, and appropriate care instituted. Definitive diagnosis requires laboratory testing and is important to identify a possible biological warfare attack and to prepare for appropriate defense. This paper reviews the viruses that cause hemorrhagic fever, and their role as possible warfare agents.

Viral hemorrhagic fever hazards for travelers in Africa.

This short review covers 6 viral hemorrhagic fevers (VHFs) that are known to occur in Africa: yellow fever, Rift Valley fever, Crimean-Congo hemorrhagic fever, Lassa fever, Marburg virus disease, and Ebola hemorrhagic fever. All of these have at one time or another affected travelers, often the adventurous kind who are "roughing it" in rural areas, who should therefore be made aware by their physicians or travel health clinics about their potential risk of exposure to any VHF along their travel route and how to minimize the risk. A significant proportion of VHF cases involving travelers have affected expatriate health care workers who were nosocomially exposed in African hospitals or clinics. The VHFs are associated with a high case-fatality rate but are readily prevented by well-known basic precautions.

O vírus Ébola e sua infecçäo / The ebola virus and its infection

As propriedades epidemiológicas, ecológicas, biológicas, patogenéticas e o diagnóstico do vírus Ébola e sua infecçåo, bem como seu controle såo apresentadas neste artigo. Embora seja um vírus endêmico em certas regiöes da Africa, o risco de disseminaçåo deste vírus para fora do continente africano tem despertado a atençåo e o interesse da comunidade médica mundial, e acionado a vigilåncia sanitária internacional para este vírus

Cell-mediated immunity to virus causing haemorrhagic fever with renal syndrome: generation of cytotoxic T lymphocytes.

Cytotoxic T lymphocytes (CTLs) were generated when spleen cells from mice infected with viruses causing haemorrhagic fever with renal syndrome were stimulated in vitro with syngeneic cells infected with viruses. These cytotoxic effector cells, with Lyt2+ L3T4- markers on their surface, demonstrated H-2 restriction. CTLs induced by Hantaan virus (76-118 strain) or Seoul virus (B-1 strain) showed cross-reactivity with infected target cells. Hantaan virus infection induced a higher CTLs response than Seoul virus infection, although the antibody responses to these two viruses and the replication of the two virus strains in athymic nude mice were not significantly different. Viral antigen detected with a monoclonal antibody reacting with nucleocapsid antigen was observed mainly in the cytoplasm of macrophages infected with Hantaan virus, but in the nucleus of cells infected with Seoul virus. The major viral antigens recognized by CTLs are discussed on the basis of these findings.