scholarly journals Diverse novel resident Wolbachia strains in Culicine mosquitoes from Madagascar

2018 ◽  
Author(s):  
Claire Louise Jeffries ◽  
Luciano M Tantely ◽  
Fara Nantenaina Raharimalala ◽  
Eliot Hurn ◽  
Sébastien Boyer ◽  
...  
Keyword(s):  
Rift Valley Fever ◽  
Sanger Sequencing ◽  
Potential Role ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Prevalence Rates ◽  
Valley Fever ◽  
Endosymbiotic Bacteria ◽  
Arboviral Transmission ◽  
Strain Characterisation

AbstractWolbachia endosymbiotic bacteria are widespread throughout insect species and Wolbachia transinfected in Aedes mosquito species has formed the basis for biocontrol programs as Wolbachia strains inhibit arboviral replication and can spread through populations. Resident strains in wild Culicine mosquito populations (the vectors of most arboviruses) requires further investigation given resident strains can also affect arboviral transmission. As Madagascar has a large diversity of both Culicine species and has had recent arboviral outbreaks, an entomology survey was undertaken, in five ecologically diverse sites, to determine the Wolbachia prevalence. We detected diverse novel resident Wolbachia strains within the Aedeomyia, Culex, Ficalbia, Mansonia and Uranotaenia genera. Wolbachia prevalence rates and strain characterisation through Sanger sequencing with multilocus sequence typing (MLST) and phylogenetic analysis revealed significant diversity and we detected co-infections with the environmentally acquired bacterial endosymbiont Asaia. Mosquitoes were screened for major arboviruses to investigate if any evidence could be provided for their potential role in transmission and we report the presence of Rift Valley fever virus in three Culex species: Culex tritaeniorhynchus, Culex antennatus and Culex decens. The implications of the presence of resident Wolbachia strains are discussed and how the discovery of novel strains can be utilized for applications in the development of biocontrol strategies.

scholarly journals An Epidemiological Model of Rift Valley Fever with Spatial Dynamics

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Tianchan Niu ◽  
Holly D. Gaff ◽  
Yiannis E. Papelis ◽  
David M. Hartley
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Horizontal Transmission ◽  
Spatial Dynamics ◽  
The United States ◽  
Trade Restrictions ◽  
Valley Fever ◽  
Supply Chain Disruptions

As a category A agent in the Center for Disease Control bioterrorism list, Rift Valley fever (RVF) is considered a major threat to the United States (USA). Should the pathogen be intentionally or unintentionally introduced to the continental USA, there is tremendous potential for economic damages due to loss of livestock, trade restrictions, and subsequent food supply chain disruptions. We have incorporated the effects of space into a mathematical model of RVF in order to study the dynamics of the pathogen spread as affected by the movement of humans, livestock, and mosquitoes. The model accounts for the horizontal transmission of Rift Valley fever virus (RVFV) between two mosquito and one livestock species, and mother-to-offspring transmission of virus in one of the mosquito species. Space effects are introduced by dividing geographic space into smaller patches and considering the patch-to-patch movement of species. For each patch, a system of ordinary differential equations models fractions of populations susceptible to, incubating, infectious with, or immune to RVFV. The main contribution of this work is a methodology for analyzing the likelihood of pathogen establishment should an introduction occur into an area devoid of RVF. Examples are provided for general and specific cases to illustrate the methodology.

Rift Valley fever virus transmission by different Egyptian mosquito species

1987 ◽  
Vol 81 (4) ◽  
pp. 694-698 ◽  
Author(s):  
Adel M. Gad ◽  
Mosaad M. Hassan ◽  
Sharif El Said ◽  
Mahmoud I. Moussa ◽  
Owen L. Wood
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Virus Transmission ◽  
Fever Virus ◽  
Valley Fever

Vector Potential of Selected North American Mosquito Species for Rift Valley Fever Virus

1988 ◽  
Vol 38 (2) ◽  
pp. 440-446 ◽  
Author(s):  
Thomas P. Gargan ◽  
David J. Dohm ◽  
Michael J. Turell ◽  
Charles L. Bailey ◽  
Gary G. Clark
Keyword(s):  
North American ◽  
Vector Potential ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Fever Virus ◽  
Valley Fever

The potential role of rodents in the enzootic cycle of Rift Valley fever virus in Senegal

2000 ◽  
Vol 2 (4) ◽  
pp. 343-346 ◽  
Author(s):  
Diop Gora ◽  
Thiongane Yaya ◽  
Thonnon Jocelyn ◽  
Fontenille Didier ◽  
Diallo Maoulouth ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Potential Role ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Valley Fever ◽  
Enzootic Cycle

scholarly journals Detection of Rift Valley Fever Virus RNA in Formalin-Fixed Mosquitoes by In Situ Hybridization (RNAscope®)

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1079
Author(s):  
Sarah Lumley ◽  
Laura Hunter ◽  
Kirsty Emery ◽  
Roger Hewson ◽  
Anthony R. Fooks ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Fever Virus ◽  
Sub Saharan Africa ◽  
Support Vector ◽  
Valley Fever

Rift Valley fever virus (RVFV) causes a zoonotic mosquito-borne haemorrhagic disease that emerges to produce rapid large-scale outbreaks in livestock within sub-Saharan Africa. A range of mosquito species in Africa have been shown to transmit RVFV, and recent studies have assessed whether temperate mosquito species are also capable of transmission. In order to support vector competence studies, the ability to visualize virus localization in mosquito cells and tissue would enhance the understanding of the infection process within the mosquito body. Here, the application of in situ hybridization utilizing RNAscope® to detect RVFV infection within the mosquito species, Culex pipiens, derived from the United Kingdom was demonstrated. Extensive RVFV replication was detected in many tissues of the mosquito with the notable exception of the interior of ovarian follicles.

scholarly journals Wolbachia effects on Rift Valley fever virus infection in Culex tarsalis mosquitoes

2017 ◽  
Author(s):  
Brittany L. Dodson ◽  
Elizabeth S. Andrews ◽  
Michael J. Turell ◽  
Jason L. Rasgon
Keyword(s):  
West Nile Virus ◽  
Virus Infection ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
West Nile Virus Infection ◽  
Fever Virus ◽  
Culex Tarsalis ◽  
Valley Fever

AbstractInnovative tools are needed to alleviate the burden of mosquito-borne diseases, and strategies that target the pathogen instead of the mosquito are being considered. A possible tactic is the use of Wolbachia, a maternally inherited, endosymbiotic bacterium that can suppress diverse pathogens when introduced to naive mosquito species. We investigated effects of somatic Wolbachia (strain wAlbB) infection on Rift Valley fever virus (RVFV) in Culex tarsalis mosquitoes. When compared to Wolbachia-uninfected mosquitoes, there was no significant effect of Wolbachia infection on RVFV infection, dissemination, or transmission frequencies, nor on viral body or saliva titers. Within Wolbachia-infected mosquitoes, there was a modest negative correlation between RVFV body titers and Wolbachia density, suggesting that Wolbachia may suppress RVFV in a density-dependent manner in this mosquito species. These results are contrary to previous work in the same mosquito species, showing Wolbachia-induced enhancement of West Nile virus infection rates. Taken together, these results highlight the importance of exploring the breadth of phenotypes induced by Wolbachia.Author SummaryAn integrated vector management program utilizes several practices, including pesticide application and source reduction, to reduce mosquito populations. However, mosquitoes are developing resistance to some of these methods and new control approaches are needed. A novel technique involves the bacterium Wolbachia that lives naturally in many insects. Wolbachia can be transferred to uninfected mosquitoes and can block pathogen transmission to humans. Additionally, Wolbachia is maternally inherited, allowing it to spread quickly through uninfected field populations of mosquitoes. We studied the impacts of Wolbachia on Rift Valley fever virus (RVFV) in the naturally uninfected mosquito, Culex tarsalis. Wolbachia had no effects on the ability of Culex tarsalis to become infected with or transmit RVFV. High densities of Wolbachia were associated with no virus infection or low levels of virus, suggesting that Wolbachia might suppress RVFV at high densities. These results contrast with our previous study that showed Wolbachia enhances West Nile virus infection in Culex tarsalis. Together, these studies highlight the importance of studying Wolbachia effects on a variety of pathogens so that control methods are not impeded.

scholarly journals Predicting the Mosquito Species and Vertebrate Species Involved in the Theoretical Transmission of Rift Valley Fever Virus in the United States

2014 ◽  
Vol 8 (9) ◽  
pp. e3163 ◽  
Author(s):  
Andrew J. Golnar ◽  
Michael J. Turell ◽  
A. Desiree LaBeaud ◽  
Rebekah C. Kading ◽  
Gabriel L. Hamer
Keyword(s):  
United States ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
The United States ◽  
Fever Virus ◽  
Vertebrate Species ◽  
Valley Fever

Description and analysis of the cattle trade network in the Madagascar highlands: Potential role in the diffusion of Rift Valley fever virus

Acta Tropica ◽  
2013 ◽  
Vol 126 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Gaëlle Nicolas ◽  
Benoît Durand ◽  
Raphaël Duboz ◽  
René Rakotondravao ◽  
Véronique Chevalier
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Potential Role ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Trade Network ◽  
Valley Fever

scholarly journals Rift Valley fever – a growing threat to humans and animals

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Małgorzata Kwaśnik ◽  
Wojciech Rożek ◽  
Jerzy Rola
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Global Climate ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Severe Disease ◽  
Clinical Signs ◽  
Wide Distribution ◽  
Sub Saharan Africa ◽  
Valley Fever

Abstract Rift Valley fever (RVF) is a zoonotic, vector-borne infectious disease of ruminants and camels transmitted mainly by the Aedes and Culex mosquito species. Contact with the blood or organs of infected animals may infect humans. Its etiological factor is the Rift Valley fever virus (RVFV) of the Phlebovirus genus and Bunyaviridae family. Sheep and goats are most susceptible to infection and newborns and young individuals endure the most severe disease course. High abortion rates and infant mortality are typical for RVF; its clinical signs are high fever, lymphadenitis, nasal and ocular secretions and vomiting. Conventional diagnosis is done by the detection of specific IgM or IgG antibodies and RVFV nucleic acids and by virus isolation. Inactivated and live-attenuated vaccines obtained from virulent RVFV isolates are available for livestock. RVF is endemic in sub-Saharan Africa and the Arabian Peninsula, but in the last two decades, it was also reported in other African regions. Seropositive animals were detected in Turkey, Tunisia and Libya. The wide distribution of competent vectors in non-endemic areas coupled with global climate change threaten to spread RVF transboundarily. The EFSA considers the movement of infected animals and vectors to be other plausible pathways of RVF introduction into Europe. A very low risk both of introduction of the virus through an infected animal or vector and of establishment of the virus, and a moderate risk of its transmission through these means was estimated for Poland. The risk of these specific modes of disease introduction into Europe is rated as very low, but surveillance and response capabilities and cooperation with the proximal endemic regions are recommended.

scholarly journals Rift Valley fever potential mosquito vectors and their infection status in Ngorongoro District in northern Tanzania

2015 ◽  
Vol 17 (4) ◽  
Author(s):  
Athanas D. Mhina ◽  
Christopher J. Kasanga ◽  
Calvin Sindato ◽  
Esron D. Karimuribo ◽  
Leonard E.G. Mboera
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Mosquito Species ◽  
Transmission Risk ◽  
Infection Status ◽  
Mosquito Vectors ◽  
Valley Fever ◽  
Breeding Sites ◽  
Ngorongoro District

Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease. Rift Valley fever virus (RVFV) has been isolated from more than 40 species of mosquitoes from eight genera. This study was conducted to determine the abundance of potential mosquito vectors and their RVFV infection status in Ngorongoro District of northern Tanzania.Methods: Adult mosquitoes were collected outdoors using the CDC light traps baited with carbon dioxide in five randomly selected villages namely, Meshili, Malambo, Osinoni, Endulen and Nainokanoka. The study was carried out towards the end of rainy season in May 2013. The traps were set in proximity to potential breeding sites and cattle kraals. The collected mosquitoes were identified to genus and species using morphological keys. They were tested for RVFV RNA  using  real time reverse transcription-polymerase chain reaction (rRT-PCR).Results: A total of 2,094 adult mosquitoes belonging to three genera and nine species were collected. Most of them (87.5%) were collected in Meshili, followed by Malambo (8.2%) and Osinoni (4%) villages. No single mosquito was collected in Nainokanoka or Endulen. The nine species collected were Culex pipiens complex, Cx. antennatus, Cx. tigripes, Cx. annulioris, Cx. cinereus, Anopheles arabiensis, An. squamosus, An. pharoensis and Mansonia uniformis. No RVFV RNA was detected in the mosquito specimens.Conclusion: Various RVFV potential mosquito species were collected from the study villages. These mosquito vectors were heterogeneously distributed in the district suggesting a variation in RVF transmission risk in the study area.

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