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Susceptibility and barriers to infection of Colorado mosquitoes with Rift Valley fever virus.

Rift Valley fever virus (RVFV) causes morbidity and mortality in humans and domestic ungulates in sub-Saharan Africa, Egypt, and the Arabian Peninsula. Mosquito vectors transmit RVFV between vertebrates by bite, and also vertically to produce infectious progeny. Arrival of RVFV into the United States by infected mosquitoes or humans could result in significant impacts on food security, human health, and wildlife health. Elucidation of the vectors involved in the post-introduction RVFV ecology is paramount to rapid implementation of vector control. We performed vector competence experiments in …

Co-circulation of Orthobunyaviruses and Rift Valley Fever Virus in Mauritania, 2015.

Ngari virus (NRIV) has been mostly detected during concurrent outbreaks of Rift Valley fever virus (RVFV). NRIV is grouped in the genus Orthobunyavirus within the Bunyaviridae family and RVFV in the genus Phlebovirus in the family Phenuiviridae. Both are zoonotic arboviruses and can induce hemorrhagic fever displaying the same clinical picture in humans and small ruminants. To investigate if NRIV and its parental viruses, Bunyamwera virus (BUNV) and Batai virus (BATV), played a role during the Mauritanian RVF outbreak in 2015/16, we analyzed serum samples of sheep and goats from central and so…

First serological evidence of the Rift Valley fever Phlebovirus in Tunisian camels.

Rift Valley fever (RVF) is a mosquito-borne zoonosis that severely impacts livelihoods, national and international economies, and human health. Few studies have investigated the prevalence of this infection in Tunisian livestock. The present report aimed to update the epidemiological status and identify the risk factors associated with this RVF virus infection in the one-humped dromedary camel from arid areas. A total of 470 sera of apparently healthy camels (Camelus dromedarius) were collected from six governorates from southern and central Tunisia. Samples were tested by a competitive Enzyme…

Rift Valley Fever: risk of persistence, spread and impact in Mayotte (France).

Rift Valley fever (RVF) is a vector-borne disease transmitted by different mosquito species, especially Aedes and Culex genus, to animals and humans. In November 2018, RVF re-emerged in Mayotte (France) after 11 years. Up to the end of October 2019, 126 outbreaks in animals and 143 human cases were reported. RVF mortality was 0.01%, and the number of abortions reported in polymerase chain reaction (PCR)-positive ruminants was fivefold greater than the previous 7 years. Milk loss production in 2019 compared to 2015-2018 was estimated to be 18%, corresponding to an economic loss of around €191,0…

Serosurvey on Sheep Unravel Circulation of Rift Valley Fever Virus in Nigeria.

Rift Valley fever is an arboviral zoonoses causing severe morbidity and mortality among humans and animals in many African countries. A cross-sectional study in populations of sheep reared around the Gidan-Waya Forest Reserve located in Jema'a LGA of Kaduna State, Nigeria to determine the serological evidence of exposure to Rift Valley fever virus (RVFV) using a commercial competitive enzyme-linked immunosorbent assay. Of the 200 sheep sampled, 9 (4.5%; 95 CI 2.23-8.33) were positive for antibodies to the RVFV. The detection of antibodies suggests a covert circulation among the sheep and may b…

Drivers for Rift Valley fever emergence in Mayotte: A Bayesian modelling approach.

Rift Valley fever (RVF) is a major zoonotic and arboviral hemorrhagic fever. The conditions leading to RVF epidemics are still unclear, and the relative role of climatic and anthropogenic factors may vary between ecosystems. Here, we estimate the most likely scenario that led to RVF emergence on the island of Mayotte, following the 2006-2007 African epidemic. We developed the first mathematical model for RVF that accounts for climate, animal imports and livestock susceptibility, which is fitted to a 12-years dataset. RVF emergence was found to be triggered by the import of infectious animals, …

The first positive serological study on rift valley fever in ruminants of Iran.

BACKGROUND & OBJECTIVES: Rift Valley fever (RVF) is a zoonotic vector-borne disease that primarily affects domestic animals but can also infect humans. The purpose of the present study was to investigate the presence of antibodies against RVF virus (RVFV) in ruminants, viz. cattle, sheep, and goats in Kurdistan Province of western Iran. METHODS: Blood samples were collected from 288 ruminants (118 cattle, 142 sheep and 28 goats) of both sexes, under age groups ≤1, 1-3, 3-5 and ≥5 yr, from January 2016 to December 2016. Clinical symptoms and history of abortion were recorded. The presence of R…

Surveillance of Rift Valley Fever Virus in Mosquito Vectors of the Republic of Korea.

Rift Valley fever (RVF) is an acute mosquito-borne viral zoonotic disease that affects mainly domestic ruminants and humans. RVF virus (RVFV) was first identified in Kenya in 1931 and was reported to be endemic in Africa but has recently spread to the Arabian Peninsula. With increasing climate change and globalization of trade in animals and animal products, there is great concern that the disease will spread worldwide to regions such as Europe, Asia, and the Americas. Although RVFV has not been reported in the Republic of Korea (ROK), the possibility of RVFV introduction is increasing because…

Predictive Factors and Risk Mapping for Rift Valley Fever Epidemics in Kenya.

BACKGROUND: To-date, Rift Valley fever (RVF) outbreaks have occurred in 38 of the 69 administrative districts in Kenya. Using surveillance records collected between 1951 and 2007, we determined the risk of exposure and outcome of an RVF outbreak, examined the ecological and climatic factors associated with the outbreaks, and used these data to develop an RVF risk map for Kenya. METHODS: Exposure to RVF was evaluated as the proportion of the total outbreak years that each district was involved in prior epizootics, whereas risk of outcome was assessed as severity of observed disease in humans a…

Seroepidemiological Survey of Rift Valley Fever Virus in Ruminants in Garissa, Kenya.

INTRODUCTION: Rift Valley fever (RVF) is a vector-borne zoonotic disease caused by phlebovirus in the family Bunyaviridae. In Kenya, major outbreaks occurred in 1997-1998 and 2006-2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade. AIM: This study was conducted to determine RVF seroprevalence in cattle, sheep, and goats during an interepidemic period in Garissa County in Kenya. METHODS: In July 2013, we performed a cross-sectional survey and sampled 370 ruminants from eight RVF-prone areas of Garissa County. Rift …

Potency of a thermostabilised chimpanzee adenovirus Rift Valley Fever vaccine in cattle.

Development of safe and efficacious vaccines whose potency is unaffected by long-term storage at ambient temperature would obviate major vaccine deployment hurdles and limit wastage associated with breaks in the vaccine cold chain. Here, we evaluated the immunogenicity of a novel chimpanzee adenovirus vectored Rift Valley Fever vaccine (ChAdOx1-GnGc) in cattle, following its thermostabilisation by slow desiccation on glass fiber membranes in the non-reducing sugars trehalose and sucrose. Thermostabilised ChAdOx1-GnGc vaccine stored for 6 months at 25, 37 or 45 ° C elicited comparable Rift Vall…

Inter-epidemic acquisition of Rift Valley fever virus in humans in Tanzania.

BACKGROUND: In East Africa, epidemics of Rift Valley fever (RVF) occur in cycles of 5-15 years following unusually high rainfall. RVF transmission during inter-epidemic periods (IEP) generally passes undetected in absence of surveillance in mammalian hosts and vectors. We studied IEP transmission of RVF and evaluated the demographic, behavioural, occupational and spatial determinants of past RVF infection. METHODOLOGY: Between March and August 2012 we collected blood samples, and administered a risk factor questionnaire among 606 inhabitants of 6 villages in the seasonally inundated Kilombero…

Serologic evidence of exposure to Rift Valley fever virus detected in Tunisia.

Rift Valley fever virus (RVFv) is capable of causing dramatic outbreaks amongst economically important animal species and is capable of causing severe symptoms and mortality in humans. RVFv is known to circulate widely throughout East Africa; serologic evidence of exposure has also been found in some northern African countries, including Mauritania. This study aimed to ascertain whether RVFv is circulating in regions beyond its known geographic range. Samples from febrile patients (n = 181) and nonfebrile healthy agricultural and slaughterhouse workers (n = 38) were collected during the summer…

Оценка эффективности векторной вакцины Рифта Вэлли у бараков.

В настоящем исследовании проводится оценка защиты, обеспечиваемой одной подкоконной дозой модифицированной векторной вакцины от вируса Vaccinia vanka (MVA), кодирующей вирус Рифта долины (RVFV) гликпротеинов Gn и Gc у ягнят. Три группы из шести-семи ягненов были иммунизированы следующим образом: одна группа получила вакцину (определенная rMVA-GnGc), вторая группа получила вектор MVA (борьба с вектором), а третья группа получила солевой раствор (непрививаемый контроль). Четырнадцать дней спустя все животные были поставлены под угрозу с помощью 10(5) TCID50 вирулента RVFV изолирующего 56/74 и оц

Совпадение в аннотации оригинала
The present study has evaluated the protection conferred by a single subcutaneous dose of a modified vaccinia virus Ankara (MVA) vectored vaccine encoding the Rift Valley Fever virus (RVFV) glycoproteins Gn and Gc in lambs. Three groups of six to seven lambs were immunized as follows: one group received the vaccine (termed rMVA-GnGc), a second group received…

Recent outbreaks of rift valley Fever in East Africa and the middle East.

Rift Valley fever (RVF) is an important neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health. Mosquitoes in the Aedes genus have been considered as the reservoir, as well as vectors, since their transovarially infected eggs withstand desiccation and larvae hatch when in contact with water. However, different mosquito species serve as epizootic/epidemic vectors of RVF, creating a complex epidemiologic pattern in East Africa. The recent RVF outbreaks in Somalia (2006-2007), Kenya (2006-2007), Tanzania (2007), and Sudan (2007-2008) showed extension to…

Creation of a recombinant Rift Valley fever virus with a two-segmented genome.

Rift Valley fever virus (RVFV; family Bunyaviridae) is a clinically important, mosquito-borne pathogen of both livestock and humans, which is found mainly in sub-Saharan Africa and the Arabian Peninsula. RVFV has a trisegmented single-stranded RNA (ssRNA) genome. The L and M segments are negative sense and encode the L protein (viral polymerase) on the L segment and the virion glycoproteins Gn and Gc as well as two other proteins, NSm and 78K, on the M segment. The S segment uses an ambisense coding strategy to express the nucleocapsid protein, N, and the nonstructural protein, NSs. Both the N…

The status of Rift Valley fever in animals in Saudi Arabia: a mini review.

In August-September 2000, an overwhelming outbreak of Rift Valley fever (RVF) struck the southwestern part of Saudi Arabia and adjoining Yemeni territories. During the outbreak, which was the first ever to be recorded outside Africa, around 40,000 animals, mostly sheep and goats, died or aborted and 883 cases, with 124 deaths, were recorded among humans in Saudi Arabia. An additional 1328 human cases, with 166 deaths, were concurrently recorded in northwestern Yemen. Vector studies in Saudi Arabia established Aedes vexans arabiensis and Culex (culex) triteniorynchus as the biological vectors o…