scholarly journals RNA Viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 144 ◽  
Author(s):  
Mathilde Gondard ◽  
Sarah Temmam ◽  
Elodie Devillers ◽  
Valérie Pinarello ◽  
Thomas Bigot ◽  
...  
Keyword(s):  
Rna Virus ◽  
Rhipicephalus Microplus ◽  
Amblyomma Variegatum ◽  
Screening Tests ◽  
Virus Diversity ◽  
High Infection ◽  
Viral Communities ◽  
High Level ◽  
Vector Capacity

Ticks transmit a wide variety of pathogens including bacteria, parasites and viruses. Over the last decade, numerous novel viruses have been described in arthropods, including ticks, and their characterization has provided new insights into RNA virus diversity and evolution. However, little is known about their ability to infect vertebrates. As very few studies have described the diversity of viruses present in ticks from the Caribbean, we implemented an RNA-sequencing approach on Amblyomma variegatum and Rhipicephalus microplus ticks collected from cattle in Guadeloupe and Martinique. Among the viral communities infecting Caribbean ticks, we selected four viruses belonging to the Chuviridae, Phenuiviridae and Flaviviridae families for further characterization and designing antibody screening tests. While viral prevalence in individual tick samples revealed high infection rates, suggesting a high level of exposure of Caribbean cattle to these viruses, no seropositive animals were detected. These results suggest that the Chuviridae- and Phenuiviridae-related viruses identified in the present study are more likely tick endosymbionts, raising the question of the epidemiological significance of their occurrence in ticks, especially regarding their possible impact on tick biology and vector capacity. The characterization of these viruses might open the door to new ways of preventing and controlling tick-borne diseases.

scholarly journals RNA viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles

2019 ◽  
Author(s):  
Mathilde Gondard ◽  
Sarah Temmam ◽  
Elodie Devillers ◽  
Valerie Pinarello ◽  
Thomas Bigot ◽  
...  
Keyword(s):  
Rna Virus ◽  
Rhipicephalus Microplus ◽  
Amblyomma Variegatum ◽  
Screening Tests ◽  
Virus Diversity ◽  
High Infection ◽  
Viral Communities ◽  
High Level ◽  
Vector Capacity

Ticks transmit a wide variety of pathogens including bacteria, parasites and viruses. Over the last decade, numerous novel viruses have been described in arthropods, including ticks, and their characterization has provided new insights into RNA virus diversity and evolution. However, little is known about their ability to infect vertebrates. As very few studies have described the diversity of viruses present in ticks from the Caribbean, we implemented an RNA-sequencing approach on Amblyomma variegatum and Rhipicephalus microplus ticks collected from cattle in Guadeloupe and Martinique. Among the viral communities infecting Caribbean ticks, we selected four viruses belonging to the Chuviridae, Phenuiviridae and Flaviviridae families for further characterization and designing antibody screening tests. While viral prevalence in individual tick samples revealed high infection rates, suggesting a high level of exposure of Caribbean cattle to these viruses, no seropositive animals were detected. These results suggest that the Chuviridae- and Phenuiviridae-related viruses identified in the present study are more likely tick endosymbionts, raising the question of the epidemiological significance of their occurrence in ticks, especially regarding their possible impact on tick biology and vector capacity. The characterization of these viruses might open the door to new ways of preventing and controlling tick-borne diseases.

scholarly journals The Characterization of RNA Viruses in Tropical Seawater Using Targeted PCR and Metagenomics

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Alexander I. Culley ◽  
Jaclyn A. Mueller ◽  
Madhi Belcaid ◽  
Elisha M. Wood-Charlson ◽  
Guylaine Poisson ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Rna Virus ◽  
Buoyant Density ◽  
Global Scale ◽  
Limited Data ◽  
Viral Genomes ◽  
Viral Communities ◽  
Seawater Samples ◽  
Photosynthesis And Respiration

ABSTRACTViruses have a profound influence on the ecology and evolution of plankton, but our understanding of the composition of the aquatic viral communities is still rudimentary. This is especially true of those viruses having RNA genomes. The limited data that have been published suggest that the RNA virioplankton is dominated by viruses with positive-sense, single-stranded (+ss) genomes that have features in common with those of eukaryote-infecting viruses in the orderPicornavirales(picornavirads). In this study, we investigated the diversity of the RNA virus assemblages in tropical coastal seawater samples using targeted PCR and metagenomics. Amplification of RNA-dependent RNA polymerase (RdRp) genes from fractions of a buoyant density gradient suggested that the distribution of two major subclades of the marine picornavirads was largely congruent with the distribution of total virus-like RNA, a finding consistent with their proposed dominance. Analyses of the RdRp sequences in the library revealed the presence of many diverse phylotypes, most of which were related only distantly to those of cultivated viruses. Phylogenetic analysis suggests that there were hundreds of unique picornavirad-like phylotypes in one 35-liter sample that differed from one another by at least as much as the differences among currently recognized species. Assembly of the sequences in the metagenome resulted in the reconstruction of six essentially complete viral genomes that had features similar to viruses in the familiesBacillarna-,Dicistro-, andMarnaviridae. Comparison of the tropical seawater metagenomes with those from other habitats suggests that +ssRNA viruses are generally the most common types of RNA viruses in aquatic environments, but biases in library preparation remain a possible explanation for this observation.IMPORTANCEMarine plankton account for much of the photosynthesis and respiration on our planet, and they influence the cycling of carbon and the distribution of nutrients on a global scale. Despite the fundamental importance of viruses to plankton ecology and evolution, most of the viruses in the sea, and the identities of their hosts, are unknown. This report is one of very few that delves into the genetic diversity within RNA-containing viruses in the ocean. The data expand the known range of viral diversity and shed new light on the physical properties and genetic composition of RNA viruses in the ocean.

scholarly journals AI-based localization and classification of skin disease with erythema

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ha Min Son ◽  
Wooho Jeon ◽  
Jinhyun Kim ◽  
Chan Yeong Heo ◽  
Hye Jin Yoon ◽  
...  
Keyword(s):  
Neural Network ◽  
Skin Diseases ◽  
Classification Model ◽  
Screening Tests ◽  
Sensitivity Score ◽  
Common Skin ◽  
Novel Method ◽  
Improved Performance ◽  
High Level

AbstractAlthough computer-aided diagnosis (CAD) is used to improve the quality of diagnosis in various medical fields such as mammography and colonography, it is not used in dermatology, where noninvasive screening tests are performed only with the naked eye, and avoidable inaccuracies may exist. This study shows that CAD may also be a viable option in dermatology by presenting a novel method to sequentially combine accurate segmentation and classification models. Given an image of the skin, we decompose the image to normalize and extract high-level features. Using a neural network-based segmentation model to create a segmented map of the image, we then cluster sections of abnormal skin and pass this information to a classification model. We classify each cluster into different common skin diseases using another neural network model. Our segmentation model achieves better performance compared to previous studies, and also achieves a near-perfect sensitivity score in unfavorable conditions. Our classification model is more accurate than a baseline model trained without segmentation, while also being able to classify multiple diseases within a single image. This improved performance may be sufficient to use CAD in the field of dermatology.

scholarly journals Diversity of Cowpea [Vigna unguiculata (L.) Walp] Landraces in Mozambique: New Opportunities for Crop Improvement and Future Breeding Programs

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 991
Author(s):  
Ana Maria Figueira Gomes ◽  
David Draper ◽  
Nascimento Nhantumbo ◽  
Rafael Massinga ◽  
José C. Ramalho ◽  
...  
Keyword(s):  
Vigna Unguiculata ◽  
Production Systems ◽  
Crop Improvement ◽  
Morphological Diversity ◽  
Ecological Zones ◽  
Nutrition Security ◽  
Food And Nutrition ◽  
High Level ◽  
Nutrition Sensitive

Cowpea (Vigna unguiculata) is a neglected crop native to Africa, with an outstanding potential to contribute to the major challenges in food and nutrition security, as well as in agricultural sustainability. Two major issues regarding cowpea research have been highlighted in recent years—the establishment of core collections and the characterization of landraces—as crucial to the implementation of environmentally resilient and nutrition-sensitive production systems. In this work, we have collected, mapped, and characterized the morphological attributes of 61 cowpea genotypes, from 10 landraces spanning across six agro-ecological zones and three provinces in Mozambique. Our results reveal that local landraces retain a high level of morphological diversity without a specific geographical pattern, suggesting the existence of gene flow. Nevertheless, accessions from one landrace, i.e., Maringué, seem to be the most promising in terms of yield and nutrition-related parameters, and could therefore be integrated into the ongoing conservation and breeding efforts in the region towards the production of elite varieties of cowpea.

scholarly journals Efficacy of two commercial synthetic pyrethroids (cypermethrin and deltamethrin) on Amblyomma variegatum and Rhipicephalus microplus strains of the south-western region of Burkina Faso

2021 ◽  
Vol 53 (3) ◽  
Author(s):  
Achille S. Ouedraogo ◽  
Olivier M. Zannou ◽  
Abel S. Biguezoton ◽  
Kouassi Yao Patrick ◽  
Adrien M. G. Belem ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Pyrethroid Resistance ◽  
Tick Control ◽  
Rhipicephalus Microplus ◽  
Amblyomma Variegatum ◽  
Synthetic Pyrethroid ◽  
Cattle Tick ◽  
Control Problems ◽  
Synthetic Pyrethroids ◽  
Western Region

AbstractSince 2011, period of the livestock invasion by the cattle tick Rhipicephalus microplus in Burkina Faso (BF), tick-control problems were exacerbated. Based on farmer’s reports, most commonly used commercial acaricides were found to be ineffective in Western South part of the country. To investigate the occurrence and extent of such acaricidal ineffectiveness, we performed the standardized larval packet test (LPT) with commercial deltamethrin (vectocid) and cypermethrin (cypertop), on two cattle tick species, the native Amblyomma variegatum and the invasive R. microplus. The resistance ratios (RR) were computed with susceptible Hounde strain of Rhipicephalus geigyi as reference. The R. microplus population showed resistance to the two acaricides tested with the highest lethal concentration (LC) values, and different resistance ratios higher than 4 (deltamethrin: RR50 = 28.18 and RR90 = 32.41; cypermethrin: RR50 = 8.79 and RR90 = 23.15). In the contrary, A. variegatum population was found to be highly susceptible to acaricides tested with low lethal concentrations and resistance ratio values (deltamethrin: RR50 = 0.5 and RR90 = 0.48; cypermethrin: RR50 = 0.68 and RR90 = 0.79). These data demonstrate high synthetic pyrethroid resistance in R. microplus strain, leading to conclude that the acaricide ineffectiveness in tick populations control remains a concern in BF.

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