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

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.

Transstadial and Horizontal Transmission of Rift Valley Fever Virus in Hyalomma Truncatum

1989 ◽  
Vol 41 (4) ◽  
pp. 491-496 ◽  
Author(s):  
Kenneth J. Linthicum ◽  
Charles L. Bailey ◽  
Thomas M. Logan ◽  
James R. Moulton ◽  
David J. Dohm
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Horizontal Transmission ◽  
Fever Virus ◽  
Valley Fever ◽  
Hyalomma Truncatum

scholarly journals Preliminary Evaluation of a Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Providing Full Protection against Heterologous Virulent Challenge in Cattle

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 748
Author(s):  
William C. Wilson ◽  
Bonto Faburay ◽  
Jessie D. Trujillo ◽  
Izabela Ragan ◽  
Sun-Young Sunwoo ◽  
...  
Keyword(s):  
Rift Valley ◽  
Subunit Vaccine ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
The United States ◽  
Fever Virus ◽  
Sub Saharan Africa ◽  
Preliminary Evaluation ◽  
Vaccine Platform ◽  
Valley Fever

Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen that causes periodic outbreaks of abortion in ruminant species and hemorrhagic disease in humans in sub-Saharan Africa. These outbreaks have a significant impact on veterinary and public health. Its introduction to the Arabian Peninsula in 2003 raised concerns of further spread of this transboundary pathogen to non-endemic areas. These concerns are supported by the presence of competent vectors in many non-endemic countries. There is no licensed RVF vaccine available for humans and only a conditionally licensed veterinary vaccine available in the United States. Currently employed modified live attenuated virus vaccines in endemic countries lack the ability for differentiating infected from vaccinated animals (DIVA). Previously, the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins, derived from the 1977 human RVFV isolate ZH548, was demonstrated in sheep. In the current study, cattle were vaccinated subcutaneously with the Gn only, or Gn and Gc combined, with either one or two doses of the vaccine and then subjected to heterologous virus challenge with the virulent Kenya-128B-15 RVFV strain, isolated from Aedes mosquitoes in 2006. The elicited immune responses by some vaccine formulations (one or two vaccinations) conferred complete protection from RVF within 35 days after the first vaccination. Vaccines given 35 days prior to RVFV challenge prevented viremia, fever and RVFV-associated histopathological lesions. This study indicates that a recombinant RVFV glycoprotein-based subunit vaccine platform is able to prevent and control RVFV infections in target animals.

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