Progress in the experimental therapy of severe arenaviral infections.

Institute for Antiviral Research & Department of Animal, Dairy & Veterinary Sciences, Utah State University, Logan, UT, USA.
Future Microbiology (Impact Factor: 4.02). 12/2011; 6(12):1429-41. DOI: 10.2217/fmb.11.132
Source: PubMed

ABSTRACT A number of viruses in the family Arenaviridae cause severe illness in humans. Lassa virus in West Africa and a number of agents in South America produce hemorrhagic fever in persons exposed to aerosolized excretions of the pathogens' rodent hosts. Because arenaviruses are not transmitted by arthropods, and person-to-person spread is rare, human infections occur singly and sporadically, and are usually not diagnosed until the patient is severely ill. Because the arenaviruses are naturally transmitted by the airborne route, they also pose a potential threat as aerosolized bioterror weapons. The broad-spectrum antiviral drug ribavirin was shown to reduce mortality from Lassa fever, and has been tested against Argentine hemorrhagic fever, but it is not an approved treatment for either disease. Human immune convalescent plasma was proven to be effective for Argentine hemorrhagic fever in a controlled trial. New treatments are needed to block viral replication without causing toxicity and to prevent the increased vascular permeability that is responsible for hypotension and shock. In this paper, we review current developments in the experimental therapy of severe arenaviral infections, focusing on drugs that have been tested in animal models, and provide a perspective on future research.

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    ABSTRACT: Junín virus (JUNV), the etiologic agent of Argentine hemorrhagic fever (AHF), is classified by the NIAID and CDC as a Category A priority pathogen. Presently, antiviral therapy for AHF is limited to immune plasma, which is readily available only in the endemic regions of Argentina. T-705 (favipiravir) is a broadly active small molecule RNA-dependent RNA polymerase inhibitor presently in clinical evaluation for the treatment of influenza. We have previously reported on the in vitro activity of favipiravir against several strains of JUNV and other pathogenic New World arenaviruses. To evaluate the efficacy of favipiravir in vivo, guinea pigs were challenged with the pathogenic Romero strain of JUNV, and then treated twice daily for two weeks with oral or intraperitoneal (i.p.) favipiravir (300 mg/kg/day) starting 1-2 days post-infection. Although only 20% of animals treated orally with favipiravir survived the lethal challenge dose, those that succumbed survived considerably longer than guinea pigs treated with placebo. Consistent with pharmacokinetic analysis that showed greater plasma levels of favipiravir in animals dosed by i.p. injection, i.p. treatment resulted in a substantially higher level of protection (78% survival). Survival in guinea pigs treated with ribavirin was in the range of 33-40%. Favipiravir treatment resulted in undetectable levels of serum and tissue viral titers and prevented the prominent thrombocytopenia and leucopenia observed in placebo-treated animals during the acute phase of infection. The remarkable protection afforded by i.p. favipiravir intervention beginning 2 days after challenge is the highest ever reported for a small molecule antiviral in the difficult to treat guinea pig JUNV challenge model. These findings support the continued development of favipiravir as a promising antiviral against JUNV and other related arenaviruses.
    PLoS Neglected Tropical Diseases 01/2013; 7(12):e2614. · 4.49 Impact Factor
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    ABSTRACT: There are currently no FDA approved vaccines or therapeutics to prevent or treat Argentine Hemorrhagic Fever (AHF). The causative agent of AHF is Junin virus (JUNV); a new world arenavirus classified as an NIAID/CDC Category A priority pathogen. The PTAP Late (L) domain motif within JUNV Z protein facilitates virion egress and transmission by recruiting host Tsg101 and other ESCRT complex proteins to promote scission of the virus particle from the plasma membrane. Here we describe a novel compound (compound 0013) that blocks the JUNV Z-Tsg101 interaction and inhibits budding of virus-like particles (VLPs) driven by ectopic expression of the Z protein and live attenuated JUNV Candid-1 strain in cell culture. As inhibition of the PTAP-Tsg101 interaction inhibits JUNV egress, compound 0013 serves as a prototype therapeutic that could reduce virus dissemination and disease progression in infected individuals. Moreover, since PTAP L-domain-mediated Tsg101 recruitment is utilized by other RNA virus pathogens (e.g. Ebola virus and HIV-1), PTAP inhibitors such as compound 0013 have the potential to function as potent broad-spectrum, host-oriented antiviral drugs. There are currently no FDA approved vaccines or therapeutics to prevent or treat Argentine Hemorrhagic Fever (AHF). The causative agent of AHF is Junin virus (JUNV); a new world arenavirus classified as an NIAID/CDC Category A priority pathogen. Here we describe a prototype therapeutic that blocks budding of JUNV and has the potential to function as a broad-spectrum antiviral drug.
    Journal of Virology 02/2014; · 4.65 Impact Factor