Humanized Mouse Model of Ebola Virus Disease Mimics the Immune Responses in Human Disease.

Animal models recapitulating human Ebola virus disease (EVD) are critical for insights into virus pathogenesis. Ebola virus (EBOV) isolates derived directly from human specimens do not, without adaptation, cause disease in immunocompetent adult rodents. Here, we describe EVD in mice engrafted with human immune cells (hu-BLT).

Inhibitors of the tick-borne, hemorrhagic fever-associated flaviviruses.

No antiviral therapies are available for the tick-borne flaviviruses associated with hemorrhagic fevers: Kyasanur Forest disease virus (KFDV), both classical and the Alkhurma hemorrhagic fever virus (AHFV) subtype, and Omsk hemorrhagic fever virus (OHFV). We tested compounds reported to have antiviral activity against members of the Flaviviridae family for their ability to inhibit AHFV replication. 6-Azauridine (6-azaU), 2'-C-methylcytidine (2'-CMC), and interferon alpha 2a (IFN-α2a) inhibited the replication of AHFV and also KFDV, OHFV, and Powassan virus.

Development of a reverse genetics system to generate recombinant Marburg virus derived from a bat isolate.

Recent investigations have shown the Egyptian fruit bat (Rousettus aegyptiacus) to be a natural reservoir for marburgviruses. To better understand the life cycle of these viruses in the natural host, a new reverse genetics system was developed for the reliable rescue of a Marburg virus (MARV) originally isolated directly from a R. aegyptiacus bat (371Bat).

Rift Valley fever, Sudan, 2007 and 2010.

To elucidate whether Rift Valley fever virus (RVFV) diversity in Sudan resulted from multiple introductions or from acquired changes over time from 1 introduction event, we generated complete genome sequences from RVFV strains detected during the 2007 and 2010 outbreaks. Phylogenetic analyses of small, medium, and large RNA segment sequences indicated several genetic RVFV variants were circulating in Sudan, which all grouped into Kenya-1 or Kenya-2 sublineages from the 2006-2008 eastern Africa epizootic. Bayesian analysis of sequence differences estimated that diversity among the 2007 and 2010 Sudan RVFV variants shared a most recent common ancestor circa 1996.

Molecular evolution of viruses of the family Filoviridae based on 97 whole-genome sequences.

Viruses in the Ebolavirus and Marburgvirus genera (family Filoviridae) have been associated with large outbreaks of hemorrhagic fever in human and nonhuman primates. The first documented cases occurred in primates over 45 years ago, but the amount of virus genetic diversity detected within bat populations, which have recently been identified as potential reservoir hosts, suggests that the filoviruses are much older. Here, detailed Bayesian coalescent phylogenetic analyses are performed on 97 whole-genome sequences, 55 of which are newly reported, to comprehensively examine molecular evolutionary rates and estimate dates of common ancestry for viruses within the family Filoviridae.

Seasonal pulses of Marburg virus circulation in juvenile Rousettus aegyptiacus bats coincide with periods of increased risk of human infection.

Marburg virus (family Filoviridae) causes sporadic outbreaks of severe hemorrhagic disease in sub-Saharan Africa. Bats have been implicated as likely natural reservoir hosts based most recently on an investigation of cases among miners infected in 2007 at the Kitaka mine, Uganda, which contained a large population of Marburg virus-infected Rousettus aegyptiacus fruit bats. Described here is an ecologic investigation of Python Cave, Uganda, where an American and a Dutch tourist acquired Marburg virus infection in December 2007 and July 2008.

Development of a PCR-restriction fragment length polymorphism protocol for rapid detection and differentiation of four cockroach vectors (group I "Dirty 22" species) responsible for food contamination and spreading of foodborne pathogens: public health importance.

Assessing the adulteration of food products and the presence of filth and extraneous materials is one of the measures that the U.S. Food and Drug Administration (FDA) utilizes in implementing regulatory actions of public health importance.

Ancient ancestry of KFDV and AHFV revealed by complete genome analyses of viruses isolated from ticks and mammalian hosts.

Background: Alkhurma hemorrhagic fever virus (AHFV) and Kyasanur forest disease virus (KFDV) cause significant human disease and mortality in Saudi Arabia and India, respectively. Despite their distinct geographic ranges, AHFV and KFDV share a remarkably high sequence identity. Given its emergence decades after KFDV, AHFV has since been considered a variant of KFDV and thought to have arisen from an introduction of KFDV to Saudi Arabia from India.

Rift Valley fever virus vaccine lacking the NSs and NSm genes is safe, nonteratogenic, and confers protection from viremia, pyrexia, and abortion following challenge in adult and pregnant sheep.

Rift Valley fever virus (RVFV) is a mosquito-borne human and veterinary pathogen causing large outbreaks of severe disease throughout Africa and the Arabian Peninsula. Safe and effective vaccines are critically needed, especially those that can be used in a targeted one-health approach to prevent both livestock and human disease. We report here on the safety, immunogenicity, and efficacy of the ΔNSs-ΔNSm recombinant RVFV (rRVFV) vaccine (which lacks the NSs and NSm virulence factors) in a total of 41 sheep, including 29 timed-pregnant ewes.

Chasing Jenner's vaccine: revisiting cowpox virus classification.

Cowpox virus (CPXV) is described as the source of the first vaccine used to prevent the onset and spread of an infectious disease. It is one of the earliest described members of the genus Orthopoxvirus, which includes the viruses that cause smallpox and monkeypox in humans. Both the historic and current literature describe "cowpox" as a disease with a single etiologic agent.

Multiple Crimean-Congo hemorrhagic fever virus strains are associated with disease outbreaks in Sudan, 2008-2009.

Background: Crimean-Congo hemorrhagic fever (CCHF) activity has recently been detected in the Kordufan region of Sudan. Since 2008, several sporadic cases and nosocomial outbreaks associated with high case-fatality have been reported in villages and rural hospitals in the region.

Principal Findings: In the present study, we describe a cluster of cases occurring in June 2009 in Dunkop village, Abyei District, South Kordufan, Sudan.

Genomic analysis reveals Nairobi sheep disease virus to be highly diverse and present in both Africa, and in India in the form of the Ganjam virus variant.

Nairobi sheep disease (NSD) virus, the prototype tick-borne virus of the genus Nairovirus, family Bunyaviridae is associated with acute hemorrhagic gastroenteritis in sheep and goats in East and Central Africa. The closely related Ganjam virus found in India is associated with febrile illness in humans and disease in livestock. The complete S, M and L segment sequences of Ganjam and NSD virus and partial sequence analysis of Ganjam viral RNA genome S, M and L segments encoding regions (396 bp, 701 bp and 425 bp) of the viral nucleocapsid (N), glycoprotein precursor (GPC) and L polymerase (L) proteins, respectively, was carried out for multiple Ganjam virus isolates obtained from 1954 to 2002 and from various regions of India.

Genetic evidence for Rift Valley fever outbreaks in Madagascar resulting from virus introductions from the East African mainland rather than enzootic maintenance.

Rift Valley fever virus (RVFV), a mosquito-borne phlebovirus, has been detected in Madagascar since 1979, with occasional outbreaks. In 2008 to 2009, a large RVFV outbreak was detected in Malagasy livestock and humans during two successive rainy seasons. To determine whether cases were due to enzootic maintenance of the virus within Madagascar or to importation from the East African mainland, nine RVFV whole genomic sequences were generated for viruses from the 1991 and 2008 Malagasy outbreaks.

High diversity and ancient common ancestry of lymphocytic choriomeningitis virus.

Lymphocytic choriomeningitis virus (LCMV) is the prototype of the family Arenaviridae. LCMV can be associated with severe disease in humans, and its global distribution reflects the broad dispersion of the primary rodent reservoir, the house mouse (Mus musculus). Recent interest in the natural history of the virus has been stimulated by increasing recognition of LCMV infections during pregnancy, and in clusters of LCMV-associated fatal illness among tissue transplant recipients.

Nosocomial outbreak of Crimean-Congo hemorrhagic fever, Sudan.

To confirm the presence of Crimean-Congo hemorrhagic fever in Sudan, we tested serum of 8 patients with hemorrhagic fever in a rural hospital in 2008. Reverse transcription-PCR identified Crimean-Congo hemorrhagic fever virus. Its identification as group III lineage indicated links to virus strains from South Africa, Mauritania, and Nigeria.

The phylogenetics and ecology of the orthopoxviruses endemic to North America.

The data presented herein support the North American orthopoxviruses (NA OPXV) in a sister relationship to all other currently described Orthopoxvirus (OPXV) species. This phylogenetic analysis reaffirms the identification of the NA OPXV as close relatives of "Old World" (Eurasian and African) OPXV and presents high support for deeper nodes within the Chordopoxvirinae family. The natural reservoir host(s) for many of the described OPXV species remains unknown although a clear virus-host association exists between the genus OPXV and several mammalian taxa.

Crimean-Congo hemorrhagic fever virus-encoded ovarian tumor protease activity is dispensable for virus RNA polymerase function.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus (genus Nairovirus, family Bunyaviridae) associated with high case fatality disease outbreaks in regions of Africa, Europe, and Asia. The CCHFV genome consists of three negative-strand RNA segments, S, M, and L. The unusually large virus L polymerase protein and the need for biosafety level 4 (BSL-4) containment conditions for work with infectious virus have hampered the study of CCHFV replication.

Genetic detection and characterization of Lujo virus, a new hemorrhagic fever-associated arenavirus from southern Africa.

Lujo virus (LUJV), a new member of the family Arenaviridae and the first hemorrhagic fever-associated arenavirus from the Old World discovered in three decades, was isolated in South Africa during an outbreak of human disease characterized by nosocomial transmission and an unprecedented high case fatality rate of 80% (4/5 cases). Unbiased pyrosequencing of RNA extracts from serum and tissues of outbreak victims enabled identification and detailed phylogenetic characterization within 72 hours of sample receipt. Full genome analyses of LUJV showed it to be unique and branching off the ancestral node of the Old World arenaviruses.

Efficient reverse genetics generation of infectious junin viruses differing in glycoprotein processing.

The New World arenaviruses, Junin, Machupo, Guanarito, Sabia, and Chapare, are associated with rapidly progressing severe hemorrhagic fever with a high rate of case fatality in various regions of South America. The threat of natural or deliberate outbreaks associated with these viruses makes the development of preventive or therapeutic measures important. Here we describe a Junin virus functional minigenome system and a reverse genetics system for production of infectious Junin virus.

Newly discovered ebola virus associated with hemorrhagic fever outbreak in Uganda.

Over the past 30 years, Zaire and Sudan ebolaviruses have been responsible for large hemorrhagic fever (HF) outbreaks with case fatalities ranging from 53% to 90%, while a third species, Côte d'Ivoire ebolavirus, caused a single non-fatal HF case. In November 2007, HF cases were reported in Bundibugyo District, Western Uganda. Laboratory investigation of the initial 29 suspect-case blood specimens by classic methods (antigen capture, IgM and IgG ELISA) and a recently developed random-primed pyrosequencing approach quickly identified this to be an Ebola HF outbreak associated with a newly discovered ebolavirus species (Bundibugyo ebolavirus) distantly related to the Côte d'Ivoire ebolavirus found in western Africa.

Multiple virus lineages sharing recent common ancestry were associated with a Large Rift Valley fever outbreak among livestock in Kenya during 2006-2007.

Rift Valley fever (RVF) virus historically has caused widespread and extensive outbreaks of severe human and livestock disease throughout Africa, Madagascar, and the Arabian Peninsula. Following unusually heavy rainfall during the late autumn of 2006, reports of human and animal illness consistent with RVF virus infection emerged across semiarid regions of the Garissa District of northeastern Kenya and southern Somalia. Following initial RVF virus laboratory confirmation, a high-throughput RVF diagnostic facility was established at the Kenyan Central Veterinary Laboratories in Kabete, Kenya, to support the real-time identification of infected livestock and to facilitate outbreak response and control activities.

The complete genome sequence of a Crimean-Congo hemorrhagic fever virus isolated from an endemic region in Kosovo.

The Balkan region and Kosovo in particular, is a well-known Crimean-Congo hemorrhagic fever (CCHF) endemic region, with frequent epidemic outbreaks and sporadic cases occurring with a hospitalized case fatality of approximately 30%. Recent analysis of complete genome sequences of diverse CCHF virus strains showed that the genome plasticity of the virus is surprisingly high for an arthropod-borne virus. High levels of nucleotide and amino acid differences, frequent RNA segment reassortment and even RNA recombination have been recently described.

Comparative genetic analysis of genomic DNA sequences of two human isolates of Tanapox virus.

Members of the genus Yatapoxvirus, which include Tanapox virus (TPV) and Yaba monkey tumor virus, infect primates including humans. Two strains of TPV isolated 50 years apart from patients infected from the equatorial region of Africa have been sequenced. The original isolate from a human case in the Tana River Valley, Kenya, in 1957 (TPV-Kenya) and an isolate from an infected traveler in the Republic of Congo in 2004 (TPV-RoC).

Patient-to-patient transmission of hepatitis B virus associated with oral surgery.

We used molecular epidemiologic techniques to document patient-to-patient transmission of hepatitis B virus (HBV) between 2 outpatient oral surgery patients operated on 161 min apart. Serological testing of 25 (93%) of 27 patients operated on after the source patient revealed that 19 (76%) of 25 were previously immune to HBV; no additional cases were identified. We found no deficiencies in infection control practices.