Replication Cycle of Astroviruses
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ABSTRACT:
SUBMITTER: Schultz-Cherry S
PROVIDER: S-EPMC7121303 | biostudies-literature | 2012 Sep
REPOSITORIES: biostudies-literature
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Project description:By screening rabbits with enterocolitis or enteritis complex and asymptomatic rabbits, we identified a novel astrovirus. The virus was distantly related (19.3%-23.7% aa identity) in the capsid precursor to other mammalian astroviruses within the Mamastrovirus genus. By using real-time reverse transcription PCR, with specific primers and probes and targeting a conserved stretch in open reading frame 1b, we found rabbit astrovirus in 10 (43%) of 23 samples from animals with enteric disease and in 25 (18%) of 139 samples from asymptomatic animals in Italy during 2005-2008. The mean and median titers in the positive animals were 10(2)× and 10(3)× greater, respectively, in the symptomatic animals than in the asymptomatic animals. These findings support the idea that rabbit astroviruses should be included in the diagnostic algorithm of rabbit enteric disease and animal experiments to increase information obtained about their epidemiology and potential pathogenic role.
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Project description:The first human astrovirus was discovered in 1975 by Madeley and Cosgrove through visualization of viral particles in stool using electron microscopy. Over the course of the next ∼20 years, an additional seven serotypes of human astroviruses were discovered. In the last decade, new technological advances in microarrays and sequencing strategies enabled more sophisticated methods for detecting viruses in clinical and environmental specimens. These methods led to the discovery of many novel viruses from a variety of virus families. They also brought about a dramatic realization that more astroviruses can be found in humans than previously recognized. In fact, the number of astroviruses associated with humans has nearly doubled within the last few years. Furthermore, the discovery of novel astroviruses in human specimens revealed that there is more diversity amongst them than was assumed based on the high level of similarity between human astroviruses 1 and 8. This chapter will describe the discovery and early characterization of the five novel astroviruses initially identified in human stool samples in 2008 and 2009.
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Project description:Several novel astroviruses have been recently discovered in humans and in other animals. Here, we report results from our surveillance of astroviruses in human and rodent faecal samples in Hong Kong. Classical human astroviruses (n=9) and a human MLB1 astrovirus were detected in human faecal samples (n=622). Novel astroviruses were detected from 1.6?% of the faecal samples of urban brown rat (Rattus norvegicus) (n=441), indicating the prevalence of astrovirus infection in rats might be much lower than that recently observed in bats. These rat astroviruses were phylogenetically related to recently discovered human astroviruses MLB1 and MLB2, suggesting that the MLB viruses and these novel rat astroviruses may share a common ancestor.
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Project description:Arboviruses (or arthropod-borne viruses), represent a threat for the new century. The 2005-2006 year unprecedented epidemics of chikungunya virus (CHIKV) in the French Reunion Island in the Indian Ocean, followed by several outbreaks in other parts of the world such as India, have attracted the attention of clinicians, scientists, and state authorities about the risks linked to this re-emerging mosquito-borne virus. CHIKV, which belongs to the Alphaviruses genus, was not previously regarded as a highly pathogenic arbovirus. However, this opinion was challenged by the death of several CHIKV-infected persons in Reunion Island. The epidemic episode began in December 2005 and four months later the seroprevalence survey report indicated that 236,000 persons, more than 30% of Reunion Island population, had been infected with CHIKV, among which 0.4-0.5% of cases were fatal. Since the epidemic peak, the infection case number has continued to increase to almost 40% of the population, with a total of more than 250 fatalities. Although information available on CHIKV is growing quite rapidly, we are still far from understanding the strategies required for the ecologic success of this virus, virus replication, its interactions with its vertebrate hosts and arthropod vectors, and its genetic evolution. In this paper, we summarize the current knowledge of CHIKV genomic organization, cell tropism, and the virus replication cycle, and evaluate the possibility to predict its future evolution. Such understanding may be applied in order to anticipate future epidemics and reduce the incidence by development and application of, for example, vaccination and antiviral therapy.
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