Background: Severe acute respiratory syndrome (SARS) is caused by a newly discovered coronavirus (SARS-CoV). No effective prophylactic or post-exposure therapy is currently available.

The largest outbreak on record of Ebola hemorrhagic fever (EHF) occurred in Uganda from

We document two clusters of LCMV infection transmitted through organ transplantation.

In March 2005, the Centers for Disease Control and Prevention (CDC) investigated a large hemorrhagic fever (HF) outbreak in Uige Province in northern Angola, West Africa. In total, 15 initial specimens were sent to CDC, Atlanta, Ga., for testing for viruses associated with viral HFs known to be present in West Africa, including ebolavirus. Marburgvirus was also included despite the fact that the origins of all earlier outbreaks were linked directly to East Africa. Surprisingly Remarkably few nucleotide differences were found among the Angolan clinical specimens (0 to 0.07%), consistent with an outbreak scenario in which a single (or rare) introduction of virus from the reservoir species into the human population was followed by person-to-person transmission with little accumulation of mutations. This is in contrast to the 1998 to 2000 marburgvirus outbreak, where evidence of several virus genetic lineages (with up to 21% divergence) and multiple virus introductions into the human population was found.

Crimean-Congo hemorrhagic fever (CCHF) virus is

Nineteen cases of suspected Crimean-Congo hemorrhagic fever reported from Turkey.

The first confirmed Rift Valley fever outbreak outside Africa was reported in September 2000, in the Arabian Peninsula. As of February 2001, a total of 884 hospitalized patients were identified in Saudi Arabia, with 124 deaths. In Yemen, 1,087 cases occurred, with 121 deaths. Laboratory diagnosis of Rift Valley fever virus (RVFV) infections included virus genetic detection and characterization of clinical specimens by reverse transcription-polymerase chain reaction, in addition to serologic tests and virus isolation. Genetic analysis of selected regions of virus S, M, and L RNA genome segments indicated little genetic variation among the viruses associated with disease. The Saudi Arabia and Yemen viruses were almost identical to those associated with earlier RVF epidemics in East Africa. Analysis of S, M, and L RNA genome segment sequence differences showed similar phylogenetic relationships among these viruses, indicating that genetic reassortment did not play an important role in the emergence of this virus in the Arabian Peninsula. These results are consistent with the recent introduction of RVFV into the Arabian Peninsula from East Africa.

Crimean-Congo hemorrhagic fever (CCHF) virus is a tick-borne member of the genus Nairovirus, family Bunyaviridae. The mature virus glycoproteins, Gn and Gc (previously referred to as G2 and G1), are generated by proteolytic cleavage from precursor proteins. The amino termini of Gn and Gc are immediately preceded by tetrapeptides RRLL and RKPL, respectively, leading to the hypothesis that SKI-1 or related proteases may be involved (A. J. Sanchez, M. J. Vincent, and S. T. Nichol, J. Virol. 76:7263-7275, 2002). In vitro peptide cleavage data show that an RRLL peptide representing the Gn processing site is efficiently cleaved by SKI-1 protease, whereas an RKPL peptide representing the Gc processing site is cleaved at negligible levels. The efficient cleavage of RRLL peptide is consistent with the known recognition sequences of SKI-1, including the sequence determinants involved in the cleavage of the Lassa virus (family Arenaviridae) glycoprotein precursor. These in vitro findings were confirmed by expression of wild-type or mutant CCHF virus glycoproteins in CHO cells engineered to express functional or nonfunctional SKI-1. Gn processing was found to be dependent on functional SKI-1, whereas Gc processing was not. Gn processing occurred in the endoplasmic reticulum-cis Golgi compartments and was dependent on an R at the ؊4 position within the RRLL recognition motif, consistent with the known cleavage properties of SKI-1. Comparison of SKI-1 cleavage efficiency between peptides representing Lassa virus GP2 and CCHF virus Gn cleavage sites suggests that amino acids flanking the RRLL may modulate the efficiency. The apparent lack of SKI-1 cleavage at the CCHF virus Gc RKPL site indicates that related proteases, other than SKI-1, are likely to be involved in the processing at this site and identical or similar sites utilized in several New World arenaviruses.