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The article offers information on the emergence of coffee ringspot virus (CoRSV). Topics discussed include information on the genetic features of coffee ringspot virus same as plant viruses; role of climate change in CoRSV emergence in terms of temperature-dependent; and views on the CoRSV research regarding the replication of virus.

Objective: Two principal vector species, Aedes aegypti and Aedes albopictus, are known for transmission of dengue (DEN) and chikungunya (CHK) in Pakistan. We aimed to investigate their spatial and temporal distribution.Methods and Results: The Maximum Entropy algorithm revealed current climatic suitability of A. albopictus by highlighting variables contributing to its spatial distribution: Land use cover was the most important environmental factor (63.1%) followed by elevation-normalised difference vegetation index (10.9%), NDVI (8.5%) and annual precipitation (7.9%). As per Normalized Difference Vegetation Index values, the vector's presence was highly likely in areas with little vegetation such as built-up spaces or uncultivated fields, and in areas with sparse vegetation such as grasslands and cultivated fields. Temperature variables showed differing effects on vector ecology with annual temperature being the most important. Logistic regression models showed that presence of the vector, build-up and distance to roads contributed significantly to the distribution of both DEN and CHIK.Conclusion: In Swabi, the mean temperatures of warmest and driest quarters are more important in the spatial distribution of A. albopictus than mean temperatures of the wettest and coldest quarters. Finally, disease modelling reflects a high probability for both DEN and CHIK in the same regions over a huge area. [ABSTRACT FROM AUTHOR]

Present work aimed to Studies the effect of temperatures on the viability of entomopathogenic H.armigera NPV virus under vitro condition. In this study the nucleopolyhedral virus (NPV), belongs to baculoviridae was isolated from naturally infected larvae of H.armigera. The effect of different temperatures on the pathogenicity of the entomopathogenic virus HaNPV to the American bollworm H. armigera was examined. The viral pathogenicity in terms of larval mortality increased with the increase of temperature; with optimal temperature of 350C for the 2nd and 4th instars larvae but the incubation period was shortened with higher incubation temperatures. However, the pathogenicity significantly decreased with the increase of the exposure period. The virus lost its infectivity after exposer to 500C for ten min. and therefore 500C considered as the thermal inactivation point of HaNPV virus. [ABSTRACT FROM AUTHOR]

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Virus particles are highly abundant in seawater and, on average, outnumber microbial cells approximately 10-fold at the surface and 16-fold in deeper waters; yet, this relationship varies across environments. Here, we examine the influence of a suite of environmental variables, including nutrient concentrations, salinity and temperature, on the relationship between the abundances of viruses and prokaryotes over a broad range of spatial and temporal scales, including along a track from the Northwest Atlantic to the Northeast Pacific via the Arctic Ocean, and in the coastal waters of British Columbia, Canada. Models of varying complexity were tested and compared for best fit with the Akaike Information Criterion, and revealed that nitrogen and phosphorus concentrations, as well as prokaryote abundances, either individually or combined, had significant effects on viral abundances in all but hypoxic environments, which were only explained by a combination of physical and chemical factors. Nonetheless, multivariate models of environmental variables showed high explanatory power, matching or surpassing that of prokaryote abundance alone. Incorporating both environmental variables and prokaryote abundances into multivariate models significantly improved the explanatory power of the models, except in hypoxic environments. These findings demonstrate that environmental factors could be as important as, or even more important than, prokaryote abundance in describing viral abundance across wide-ranging marine environments [ABSTRACT FROM AUTHOR]

Global climate change-induced warming of the Artic seas is predicted to shift the phytoplankton community towards dominance of smaller-sized species due to globalwarming. Yet, little is known about their viral mortality agents despite the ecological importance of viruses regulating phytoplankton host dynamics and diversity. Here we report the isolation and basic characterization of four prasinoviruses infectious to the common Arctic picophytoplankter Micromonas. We furthermore assessed how temperature influenced viral infectivity and production. Phylogenetic analysis indicated that the putative double-stranded DNA (dsDNA) Micromonas polaris viruses (MpoVs) are prasinoviruses (Phycodnaviridae) of approximately 120 nm in particle size. One MpoV showed intrinsic differences to the other three viruses, i.e., larger genome size (205 -- 2 vs. 191 -- 3 Kb), broader host range, and longer latent period (39 vs. 18 h). Temperature increase shortened the latent periods (up to 50%), increased the burst size (up to 40%), and affected viral infectivity. However, the variability in response to temperature was high for the different viruses and host strains assessed, likely affecting the Arctic picoeukaryote community structure both in the short term (seasonal cycles) and long term (global warming). [ABSTRACT FROM AUTHOR]

Filoviruses are strongly associated with several species of bats as their natural reservoirs. In this study, we determined the replication potential of all filovirus species: Marburg marburgvirus, Taï Forest ebolavirus, Reston ebolavirus, Sudan ebolavirus, Zaire ebolavirus, and Bundibugyo ebolavirus. Filovirus replication was supported by all cell lines derived from 6 Old and NewWorld bat species: the hammerheaded fruit bat, Buettikofer's epauletted fruit bat, the Egyptian fruit bat, the Jamaican fruit bat, the Mexican free-tailed bat and the big brown bat. In addition, we showed thatMarburg virus Angola and Ebola virusMakona-WPGC07 efficiently replicated at 37°C, 37°-41°C, or 41°C, contrary to the hypothesis that temporal elevation in temperature due to flight affects filovirus replication in bats. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) replication is strongly dependent upon a programmed ribosomal frameshift. Here we investigate the relationships between the thermodynamic stability of the HIV type 1 (HIV-1) RNA frameshift site stem-loop, frameshift efficiency, and infectivity, using pseudotyped HIV-1 and HEK293T cells. The data reveal a strong correlation between frameshift efficiency and local, but not overall, RNA thermodynamic stability. Mutations that modestly increase the local stability of the frameshift site RNA stem-loop structure increase frameshift efficiency 2-fold to 3-fold in cells. Thus, frameshift efficiency is determined by the strength of the thermodynamic barrier encountered by the ribosome. These data agree with previous in vitro measurements, suggesting that there are no virus- or host-specific factors that modulate frameshifting. The data also indicate that there are no sequence-specific requirements for the frameshift site stem-loop. A linear correlation between Gagpolymerase (Gag-Pol) levels in cells and levels in virions supports the idea of a stochastic virion assembly mechanism. We further demonstrate that the surrounding genomic RNA secondary structure influences frameshift efficiency and that a mutation that commonly arises in response to protease inhibitor therapy creates a functional but inefficient secondary slippery site. Finally, HIV-1 mutants with enhanced frameshift efficiencies are significantly less infectious, suggesting that compounds that increase frameshift efficiency by as little as 2-fold may be effective at suppressing HIV-1 replication. [ABSTRACT FROM AUTHOR]

As the most abundant biological entities on the planet, viruses are involved in global biogeochemical cycles, and they have been shown to play an important role in the overall functioning of the deep-sea ecosystem. Nevertheless, little is known about whether and how deep-sea viruses affect the physiology of their bacterial hosts. Previously, the filamentous phage SW1 was identified in the bathypelagic bacterium Shewanella piezotolerans WP3, which was isolated from the upper sediment of West Pacific ocean. In this study, phage SW1 was shown to be active under in situ environmental conditions (20 MPa and 4°C) by transmission electron microscopy and reverse-transcription quantitative polymerase chain reaction. Further comparative analysis showed that SW1 had a significant influence on the growth and transcriptome of its host. The transcription of genes responsible for basic cellular activities, including the transcriptional/translational apparatus, arginine synthesis, purine metabolism and the flagellar motor, were down-regulated by the phage. Our results present the first characterization of a phage-host interaction under high-pressure and low-temperature conditions, which indicated that the phage adjusted the energy utilization strategy of the host for improved survival in deep-sea environments. [ABSTRACT FROM AUTHOR]

We developed a method for the fast transformation of virions of tobacco mosaic virus (TMV) in so-called spherical particles (SPs) of different sizes. These SPs turned out to be highly useful for the preparation of different kinds of important biotechnological products. In this communication, we report that a representative of the flexuous helical virus group-potato virus X (PVX), produces SPs as well, but these SPs differ from TMV SPs in several important aspects. PVX SPs may be useful biotechnological devices. [ABSTRACT FROM AUTHOR]

Southern rice black-streaked dwarf virus (SRBSDV) is a novel virus transmitted by white-backed planthopper Sogatella furcifera (Hováth) (Hemiptera: Delphacidae). Due to low virus transmission efficiency by the planthopper, researchers are frequently confronted with shortage of viruliferous vectors or infected rice plants, especially in winter and the following spring. To find new ways to maintain virus-infected materials, viral rice plants were stored at -80°C for 45 or 140 d and evaluated as virus sources in virus transmission by the vector. SRBSDV virions were not degraded during storage at -80°C as indicated by reverse transcription-polymerase chain reaction and reverse transcription real-time PCR detection. The planthopper nymphs fed on the infected thawed plants for 48 h survived at about 40% and showed positive detection of SRBSDV, but they lost the virus after feeding for another 20 d (the circulative transmission period) on noninfected plants. Transmission electron microscope images indicated broken capsid of virions in infected thawed leaves in contrast to integrity capsid of virions in infected fresh leaves. These results show that low temperature storage of SRBSDV-infected rice plants cannot sustain virus transmission by white-backed planthopper. [ABSTRACT FROM AUTHOR]

The article discusses the storage of the Chikungunya virus (CHIKV) samples at different temperatures. Topics discussed include the importance of understanding the environmental stability and survival of CHIKV, the role of the minimum essential medium (MEM) for frozen serum samples and mentions the usage of software PASW for statistical analysis.

Background The effect of transport temperature on the viability of poliovirus in stool specimens from paralyzed cases has not been tested. Quality assurance of programmatic indicators will be necessary in the final phase of polio eradication. Objective To estimate the effect of time at elevated temperatures on wild poliovirus titers in stool specimens. Methods We exposed aliquots of pooled wild poliovirus type 1 specimens to elevated temperatures (27 °C, 31 °C, and 35 °C) for varying time periods up to 14 days. We determined the virus titer of these aliquots and created decay curves at each temperature to estimate the relationship between time at temperature and virus titer. Results We found significantly different slopes of decay at each temperature. The negative slopes increased as the temperature increased. Conclusions While poliovirus in stool remains relatively stable at moderately elevated temperature, transport at higher temperatures could impact sample integrity and virus isolation results. [ABSTRACT FROM AUTHOR]

Experimental studies in guinea pigs demonstrated that influenza virus transmission is strongly modulated by temperature and humidity. A number of epidemiological studies have followed up on these findings and revealed robust associations between influenza incidence in temperate regions and local conditions of humidity and temperature, offering a long-awaited explanation for the wintertime seasonality of influenza in these locales. Despite recent progress, important questions remain as to the mechanism(s) by which humidity and/or temperature affects transmission. [ABSTRACT FROM AUTHOR]

Abstract: Determining the stability, or persistence in an infectious state, of foodborne viral pathogens attached to surfaces of soft fruits and salad vegetables is essential to underpin risk assessment studies in food safety. Here, we evaluate the effect of temperature and sunlight on the stability of infectious human adenoviruses type 2 and MS2 bacteriophages on lettuce and strawberry surfaces as representative fresh products. Human adenoviruses have been selected because of their double role as viral pathogens and viral indicators of human fecal contamination. Stability assays were performed with artificially contaminated fresh samples kept in the dark or under sunlight exposure at 4 and 30°C over 24h. The results indicate that temperature is the major factor affecting HAdV stability in fresh produce surfaces, effecting decay between 3 and 4 log after 24h at 30°C. The inactivation times to achieve a reduction between 1 and 4-log are calculated for each experimental condition. This work provides useful information to be considered for improving food safety regarding the transmission of foodborne viruses through supply chains. [Copyright &y& Elsevier]

Viral surrogates are widely used by researchers to predict human norovirus behavior. Murine norovirus (MNV) is currently accepted as the best surrogate and is assumed to mimic the survival and inactivation of human noroviruses. Recently, a new calicivirus, the Tulane virus (TV), was discovered, and its potential as a human norovirus surrogate is being explored. This study aimed to compare the behavior of the two potential surrogates under varying treatments of pH (2.0 to 10.0), chlorine (0.2 to 2,000 ppm), heat (50 to 75°C), and survival in tap water at room (20°C) and refrigeration (4°C) temperatures for up to 30 days. Viral infectivity was determined by the plaque assay for both MNV and TV. There was no significant difference between the inactivation of MNV and TV in all heat treatments, and for both MNV and TV survival in tap water at 20°C over 30 days. At 4°C, MNV remained infectious over 30 days at a titer of approximately 5 log PFU/ml, whereas TV titers decreased significantly by 5 days. MNV was more pH stable, as TV titers were reduced significantly at pH 2.0, 9.0, and 10.0, as compared with pH 7.0, whereas MNV titers were only significantly reduced at pH 10.0. After chlorine treatment, there was no significant difference in virus with the exception of at 2 ppm, where TV decreased significantly compared with MNV. Compared with TV, MNV is likely a better surrogate for human noroviruses, as MNV persisted over a wider range of pH values, at 2 ppm of chlorine, and without a loss of titer at 4°C. [ABSTRACT FROM AUTHOR]

Norovirus (NoV) and hepatitis A virus (HAV) are pathogenic enteric viruses responsible for public health concerns worldwide. The viral transmission occurs through fecally contaminated food, water, fomites, or direct contact. However, the difficulty in cultivating these viruses makes it a challenge to characterize the resistance to various environmental stresses. In this study, we characterized the inactivation rates of murine norovirus (MNV), MS2, and HAV on either lacquer coating rubber tree wood or stainless steel under different temperature and relative humidity (RH) conditions. The viruses were analyzed at temperatures of 15 °C, 25 °C, 32 °C, and 40 °C and at RHs of 30%, 50%, and 70% for 30 days. Overall, they survived significantly longer on wood than on steel at lower temperature (P < 0.05). The inactivation rate of MS2 and MNV increased at higher RH levels, whereas HAV survived the best at a medium RH level (50%). The effect of RH was significant only for MS2 (P < 0.05). MS2 persisted longest under all of the environmental conditions examined. Both a linear and a nonlinear Weibull model were used to describe the viral inactivation data in this study. The data produced a better fit to the survival curves that were predicted by the Weibull model. [ABSTRACT FROM AUTHOR]

The West African outbreak of Ebola virus (EBOV) is largely contained, but sporadic new cases continue to emerge. To assess the potential contribution of fomites to human infections with EBOV, we tested EBOV stability in human blood spotted onto Sierra Leonean banknotes and in syringe needles under hospital and environmental conditions. Under some of these conditions, EBOV remained infectious for >30 days, indicating that EBOV-contaminated items may pose a serious risk to humans. [ABSTRACT FROM AUTHOR]

Summary: A human influenza B/Lee/40 virus was cold-adapted by serial passages in embryonated chicken eggs, at progressively lower temperatures, for possible use as a future influenza B vaccine donor strain. Temperature sensitive and cold-adapted phenotypes were achieved as a consequence of the adaptation process. It was determined that the virus was attenuated in mice since the replication of the viral genome was significantly reduced in the lung. Despite decreased viral replication, the attenuated infection effectively induced a virus-specific immune response. We next developed a reassortant virus carrying two major surface proteins, hemagglutinin and neuraminidase from virulent B/Shangdong/7/97 and six internal genes from the cold-adapted B/Lee/40. The reassortant virus was also attenuated and protected mice from lethal challenge with wild type B/Shangdong/7/97. In addition, vaccination with the reassortant virus resulted in a specific antibody response and inhibited the replication of wild type virus in mice. We conclude that the cold-adapted B/Lee/40 donor strain merits further investigation as potential live vaccine carrier as an alternative means for protection from influenza B virus epidemics. [Copyright &y& Elsevier]

Background: Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14–27 °C, mean 23 °C) temperature regimes. Results: The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations. Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7–23% and 7–10% for the constant temperature and 0–10% and 3–27% under fluctuating temperatures for the Swiss and the French populations, respectively. Conclusions: To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics. [ABSTRACT FROM AUTHOR]

The article discusses a study which examines how the double-stranded DNA virus SIRV2 maintains its genomic integrity under extreme conditions.

Viruses are the most abundant and of greatest diversity life-forms in the World's Ocean, creating the highest natural selective force on the cellular life. The effect of virus infection has much broader ecological implications for ecosystem functioning than just mortality of host organisms. Viral activity promotes the cycling of nutrients within microbial loop, suppresses transfer of energy and organic matter to higher trophic levels, drives particle aggregation and enhance sinking, determines community structure, temporarily improves fitness, survival and/or resistance of infected cells, modulates gene transfer via transduction and regulates population (bloom) dynamics. Virus-host interaction models predict that viral predation is a key controlling mechanism for community regulation in highly productive coastal ecosystems. However, the role of viruses in the coastal lagoons of the Baltic Sea is largely overlooked and lacks a detailed description of their seasonal dynamics and spatial distribution as well as virus-mediated processes such as bacterial mortality and recycling of carbon and nutrients. In addition, none of the studies performed in the Baltic Sea region to date addressed the question of how climate change and in particular global warming might influence virus activity in terms of virus production and virus induced bacterial mortality. This study aimed to evaluate the patterns of virus-host interactions based on the assessment of viral impact upon host community structure, abundance and mortality. The research involved field sampling surveys and mesocosm experiments using natural microbial communities from two different Baltic Sea coastal ecosystems, the Curonian Lagoon (Lithuania) and Kiel Fjord (Germany). The mesocosm experiments in the Kiel Fjord were performed in climate change perspective by evaluating the effect of temperature change on virus-induced bacterial mortality. The research broadens our understanding about the role of viruses in the microbial loop by providing evidence for significant virus contribution to prokaryotic community regulation in the studied ecosystems. This study also attempts to provide an insight into how climate change will affect biotic interactions and, thus, ecosystem services. The mesocosm experiments revealed the possibly existing temperature threshold significantly modulating virus activity. Further, this dissertation addresses the question of how field-based observations and experimental results might explain possible feedback processes of different types of interactions in the context of ecosystem functioning, eutrophication and global warming, and provide insights into how habitat with all its complexity by covering physical, chemical and biological elements rather than individual factor allows better understanding of the ecology of viruses in the coastal environments of the Baltic Sea. [ABSTRACT FROM AUTHOR]