Natural invertebrate hosts of iridoviruses (Iridoviridae) (original) (raw)
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Iridoviruses Infecting Terrestrial Isopods and Nematodes
Iridoviridae, 1985
Iridoviruses of terrestrial isopods (IIV) were first described in detail in 1980 (FEDERICI 1980; COLE and MORRIS 1980) although the distinct purple to blue iridescent coloration produced in infected individuals had been noticed by many individuals long before. The iridovirus isolated from the pillbug, Armadillidium vulgare was designated type 31 and that from the sowbug, Porcellio dilatatus, type 32 (FEDERICI 1980), although it was suggested that they were in fact the same virus. COLE and MORRIS (1980) characterized the iridoviruses from A. vulgare and Porcellio scaber and determined that they were indeed identical in structural appearance, in biochemical properties, and serologically. This same
A comparison of techniques for detecting Invertebrate iridescent virus 6
Journal of Virological Methods, 2001
The aim of this study was to compare the sensitivity and precision of various methods for the detection and quantification of In6ertebrate iridescent 6irus 6 (IIV-6) (Irido6iridae) isolated from a the stem-boring moth Chilo suppressalis, and to apply these techniques to the detection of covert infections in the wax moth, Galleria mellonella. The relationship between the virus concentration and absorbance at 260 nm was linear over the range of 1.6×10 9 -5.6× 10 10 particles/ml. TCID 50 assays using 12 different cell lines indicated that two Drosophila lines, DL2 and DR1, had the highest susceptibility whereas cell lines from Aedes albopictus and Plutella xylostella were four orders of magnitude less sensitive. TCID 50 values for IIV-6 in Spodoptera frugiperda Sf9 cells gave the particle-infectivity ratios of 15-64 virus particles/IU. An insect bioassay involved injecting doses of 1 -100 IIV-6 particles into the third instar G. mellonella larvae. The prevalence of patent infection was 20 -26% at a dose of 1 particle per larva rising to 86-92% at 10 particles and 100% at doses of 50 or 100 particles. Of the insects that survived to adulthood, between 5.8 and 75% caused patent infections when injected into G. mellonella larvae, indicating that they were covertly infected. A PCR technique resulted in 95% detection at 1000 virus particles per insect. Of the insects that proved positive for covert infection by insect bioassay, 41% also proved positive by PCR analysis. It is concluded that the G. mellonella bioassay is highly reliable for detection of doses of 10 particles or more and for determining the relative activity of IIV-6 preparations at doses as low as 1 particle per insect. PCR had a slightly lower sensitivity followed by the insect cell culture assay.
Invertebrate Iridoviruses: A Glance over the Last Decade
Viruses, 2018
Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve clas...
Iridovirus infection in terrestrial isopods from Sicily (Italy)
Tissue and Cell, 2013
During our researches on systematics and ecology of terrestrial isopods, carried out in western Sicily, some specimens showing a blue-purple coloration were collected; they belonged to four species: Armadillidium decorum Brandt, 1833, Trichoniscus panormidensis , Philoscia affinis Verhoeff, 1908, Porcellio siculoccidentalis Viglianisi et al., 1992 We hypothesized that such coloration could be due, as reported in literature, to characteristic paracrystalline arrays of virions inside the tissues of blue colored specimens. Ultrastructural observations by transmission electron microscopy, on tissues of A. decorum, showed the presence of electron-dense viral particles, with a diameter of nearly 0.12 m. Dual-axis tomography, performed on specimens of A. decorum, evidenced an icosahedral structure of viral particles matching with that of Isopod Iridescent Virus (IIV). Molecular analysis, on 254 bp portion of the major capsid protein (MCP) gene, allowed to place the virus into IIV-31 group, already known for other oniscidean species. The symptoms of infected individuals and the course of the disease were followed in laboratory, indicating similarities with other studies on Isopod Iridoviruses. Moreover, some notes on reproduction of infected ovigerous females are reported. Our data support unequivocal and direct evidences for the first case of IIV infection in terrestrial isopods reported in Italy.
Neotropical Entomology, 2020
Iridoviridae is a DNA virus family that affects both vertebrates and invertebrates. Immature aquatic stages of many dipteran species infected with iridovirus have been found in different places worldwide. The most represented genera of the Culicidae family are Aedes and Psorophora. To date, sixteen species of Aedes naturally infected with iridoviruses have been reported. Moreover, there are four records for the genus Psorophora, one for Culiseta, and two for Culex. In this paper, we report two new mosquito species as natural hosts of iridoviridae in Argentina: Aedes albifasciatus (Macquart) and Culex dolosus (Lynch Arribalzaga). We also analyzed the ability of a Cx. pipiens-Invertebrate Iridescent Virus to replicate in vivo in the larval stage of two mosquito species, Culex apicinus Philippi and Ae. aegypti (L.) using Strelkovimermis spiculatus as a vector, under laboratory conditions. Although Ae. aegypti is the most recognized mosquito vector of important arboviruses responsible for emergent diseases, Cx. apicinus and Ae. albifasciatus may also be implicated in enzootic or epizootic cycles of virus transmission, such as the St. Louis Encephalitis virus and the Western Equine Encephalomyelitis virus.
Persistence of invertebrate iridescent virus 6 in tropical artificial aquatic environments
Archives of Virology, 2005
The rate of loss of activity of invertebrate iridescent virus 6 (IIV-6, family Iridoviridae) was determined in two artificial aquatic habitats in southern Mexico, using a sensitive insect bioassay technique. IIV-6 placed in trays of water in direct sunlight suffered rapid loss of activity (99.99% reduction) over a period of 36 h, during which water temperatures fluctuated between 24 and 41 • C. No significant deactivation occurred during the hours of darkness. In contrast, IIV-6 placed in trays of water in the shade lost 97% of original activity over a 60 h period, during which water temperatures fluctuated from 24 to 31 • C. Longitudinal analysis involving mixed effects models of time (shade) and cumulative exposure to ultraviolet radiation (sunlight) indicated that the rate of deactivation was best described by third order polynomial equations in both cases. We conclude that the likelihood of transmission of IIVs in aquatic habitats will be mediated by the intensity of UV radiation and water temperature. * Invertebrate iridescent viruses (IIVs) (family Iridoviridae) are icosahedral particles containing a large (∼200 kb) dsDNA genome [2]. These viruses infect many invertebrate species worldwide, especially the aquatic larval stages of medically important vectors, such as mosquitoes and blackflies . The ability of IIVs to persist in the environment is poorly understood. Ultraviolet radiation has been used frequently to deactivate iridoviruses for laboratory studies , and in aquaculture to sterilize the water of fish farm nurseries . Laboratory studies indicate that moisture appears to be crucial to IIV survival and
Virus Fitopatógenos en Insectos Asociados Al Ajo
Revista Chapingo Serie Horticultura, 2014
La propagación vegetativa del ajo (Allium sativum) es la principal vía de transmisión de virus para este cultivo. No obstante, no se debe descartar la dispersión por insectos vectores. El objetivo del presente estudio fue detectar, mediante la prueba de ELISA, la presencia de virus en insectos colectados en plantas de ajo. El experimento se llevó a cabo durante el ciclo Otoño-Invierno 2008-2009. La toma de muestras de insectos se realizó en tres fechas después de la siembra. La identificación de las especies de insectos se realizó utilizando un estereomicroscopio Zeiss de 30X y claves taxonómicas. La detección de virus fue mediante la técnica de DAS-ELISA para los potyvirus Virus del rayado amarillo del puerro (Leek yellow spot virus: LYSV) y Virus del enanismo amarillo de la cebolla (Onion yellow dwarf virus: OYDV); los carlavirus Virus latente común del ajo (Garlic common latent virus: GCLV) y Virus latente del chalote (Shallot latent virus: SLV); y el tospovirus Virus del manchado amarillo del iris (Iris yellow spot virus: IYSV). Se identificaron 19 especies de insectos, de los que destacaron Thrips tabaci Lindeman, como positivo en 18 muestras para GCLV y dos muestras para IYSV, y Collops quadrimaculatus, como positivo en una muestra para GCLV.
Entomopathogenic Viruses in the Neotropics: Current Status and Recently Discovered Species
Neotropical Entomology, 2020
The market for biological control of insect pests in the world and in Brazil has grown in recent years due to the unwanted ecological and human health impacts of chemical insecticides. Therefore, research on biological control agents for pest management has also increased. For instance, insect viruses have been used to protect crops and forests around the world for decades. Among insect viruses, the baculoviruses are the most studied and used viral biocontrol agent. More than 700 species of insects have been found to be naturally infected by baculoviruses, with 90% isolated from lepidopteran insects. In this review, some basic aspects of baculovirus infection in vivo and in vitro infection, gene content, viral replication will be discussed. Furthermore, we provide examples of the use of insect viruses for biological pest control and recently characterized baculoviruses in Brazil. Entomopatogenic Viruses Conventionally, viruses are isolated from insects with visible symptoms of infection (Liu et al 2011a). Baculovirus infections