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Ability of a mutagenized virus variant to protect young lambs from Rift Valley fever.

A live attenuated vaccine virus variant of Rift Valley fever (RVF) virus was developed by passaging a human isolate in tissue culture under the influence of the mutagen 5-fluorouracil. This virus variant (MV P12) has been assessed in this study as to its suitability as a vaccine, by testing its pathogenicity in young lambs and measuring its ability to induce a protective immune response. Even high doses of the vaccine virus failed to induce any of the clinical or histopathologic changes associated with classical RVF virus infection. Although the vaccine induced mild pyrexia when given in high …

Transmission of Rift Valley fever virus by the sand fly, Phlebotomus duboscqi (Diptera: Psychodidae).

Studies were conducted to determine if the sand fly Phlebotomus duboscqi could serve as a vector of Rift Valley fever (RVF) virus. When 145 P. duboscqi were fed on a hamster with RVF viremia (approximately 10(9) PFU/ml of blood), 72 (50%) became infected. Of 5 with disseminated infections (i.e., virus recovered from their legs) 4 transmitted virus to hamsters by bite. Sand flies were uniformly infected when RVF virus was inoculated by the intrathoracic route, and each of 31 sand flies so inoculated that fed on a hamster transmitted virus. None of 331 progeny of inoculated sand flies or 230 pro…

Rift Valley fever infection of rhesus monkeys: implications for rapid diagnosis of human disease.

Rhesus monkeys inoculated with Rift Valley fever (RVF) virus provide a model in which serial observations of serum viral antigen and antibodies can be made. In 9 non-fatal and 3 fatal infections, either antigen or IgM enzyme-linked immunosorbent assay (ELISA) antibodies were detected in every serum sample during the acute phase. Furthermore, viral nucleic acid could be detected by filter hybridization in most samples taken on days 1 to 3. Circulation of significant quantities of viral RNA provides an additional approach to the diagnosis and study of RVF.

Isolation of Rift Valley fever virus from human peripheral blood mononuclear cells: Mauritanian epidemic.

During the Mauritanian Rift Valley fever (RVF) epidemic of 1987, peripheral blood mononuclear cells (PBMC) were studied from 78 sick patients. RVF virus (RVFV) was isolated in 5 cases, on Aedes pseudoscutellaris AP61, from both PBMC and serum. Among the 78 cases studied, RVF was proven in 19 cases (24.3%) by specific IgM detection, and in 12 cases (15.3%) by virus isolation from serum, of which 3 also exhibited anti-RVF IgM. Among the 5 PBMC-positive RVFV cases, 2 strains were isolated in the presence of specific IgM from patients presenting with neurologic signs. These observations raised the…

Detection of Rift Valley fever viral activity in Kenya by satellite remote sensing imagery.

Data from the advanced very high resolution radiometer on board the National Oceanic and Atmospheric Administration's polar-orbiting meteorological satellites have been used to infer ecological parameters associated with Rift Valley fever (RVF) viral activity in Kenya. An indicator of potential viral activity was produced from satellite data for two different ecological regions in Kenya, where RVF is enzootic. The correlation between the satellite-derived green vegetation index and the ecological parameters associated with RVF virus suggested that satellite data may become a forecasting tool f…

Enzyme-linked immunosorbent assay for detection of Rift Valley fever virus antigen in mosquitoes.

An enzyme-linked immunosorbent assay (ELISA) was used to measure the quantity of Rift Valley fever (RVF) viral antigen in infected Egyptian Culex pipiens. Infectivity, as measured by plaque assay, was significantly correlated with viral antigen, as measured by the ELISA, in all groups of mosquitoes regardless of the time interval after the infectious blood meal. The proportion of noninfectious viral antigen in these groups increased with time. When individual mosquitoes were assayed the plaque assay and the ELISA techniques had similar sensitivity (100% vs. 93%, respectively) and specificity (…

Enhanced efficacy of liposome-encapsulated ribavirin against Rift Valley fever virus infection in mice.

Administration of liposome-encapsulated ribavirin to mice led to ribavirin concentrations in the liver, the primary site of Rift Valley fever virus proliferation, that were fivefold greater than those attained with the same doses of free ribavirin. Liposomal ribavirin given at a dose of either 25 or 50 mg of drug per kg of body weight protected mice against a rapidly lethal high-titer challenge with Rift Valley fever virus, whereas similar doses of free drug or empty liposomes had no detectable benefit. Hence, tissue targeting of ribavirin with liposomes substantially increased the therapeutic…

The Rift Valley fever epizootic in Egypt 1977-78. 2. Ecological and entomological studies.

Epidemiological factors related to the introduction, spread and maintenance of Rift Valley fever (RVF) virus were studied during the 1977-78 epizootic in Egypt, Culex pipiens is the most ubiquitous and prevalent mosquito species in the Nile Valley and Delta. Isolation of RVF virus from unengorged C. pipiens, and demonstration of laboratory transmission of the virus by this species, strongly implicate it as the chief vector in Egypt. Virus transmission to man also occurs by contamination when handling infected meat and by inhaling natural virus aerosols. Wild rodents apparently do not serve as …

Detection of Crimean-Congo hemorrhagic fever virus and Rift Valley fever virus antibodies in animal workers in Cameroon.

INTRODUCTION: Crimean-Congo hemorrhagic fever virus (CCHFV) and Rift Valley fever virus (RVFV) are emerging arboviruses primarily affecting domestic animals. Research has demonstrated their endemicity in various parts of the world, including Africa. Despite the high seroprevalence of CCHFV infection recently reported among cattle in Cameroon, the epidemiological status of animal workers who frequently interact with these animals remains poorly understood. This study investigates the seroprevalence of CCHFV and RVFV infections, along with associated factors, among animal workers in Cameroon. M…

First Serological Evidence of Crimean-Congo Hemorrhagic Fever Virus and Rift Valley Fever Virus in Ruminants in Tunisia.

Crimean-Congo hemorrhagic fever virus (CCHFV, Nairoviridae family) and Rift Valley fever virus (RVFV, Phenuiviridae family) are zoonotic vector-borne pathogens with clinical relevance worldwide. Our study aimed to determine seroprevalences of these viruses and potential risk factors among livestock (cattle, sheep, and goats) in Tunisia. Sera were tested for antibodies against CCHFV (n = 879) and RVFV (n = 699) using various enzyme-linked immunosorbent assays (ELISAs) and indirect immunofluorescence assays (IIFA). The overall seroprevalence of IgG antibodies was 8.6% (76/879) and 2.3% (16/699) …

Interventions against West Nile virus, Rift Valley fever virus, and Crimean-Congo hemorrhagic fever virus: where are we?

ARBO-ZOONET is an international network financed by the European Commission's seventh framework program. The major goal of this initiative is capacity building for the control of emerging viral vector-borne zoonotic diseases, with a clear focus on West Nile virus, Rift Valley fever virus, and Crimean-Congo hemorrhagic fever virus. To evaluate the status quo of control measures against these viruses, an ARBO-ZOONET meeting was held in Istanbul, Turkey, from 19 to 20 November 2009. The symposium consisted of three themes: (1) vaccines: new and existing ones; (2) antivirals: existing and new deve…

Diagnostic serology test comparison for Q fever and Rift Valley fever in humans and livestock from pastoral communities.

Q fever (QF) and Rift Valley fever (RVF) are endemic zoonotic diseases in African countries, causing significant health and economic burdens. Accurate prevalence estimates, crucial for disease control, rely on robust diagnostic tests. While enzyme-linked immunosorbent assays (ELISA) are not the gold standard, they offer rapid, cost-effective, and practical alternatives. However, varying results from different tests and laboratories can complicate comparing epidemiological studies. This study aimed to assess the agreement of test results for QF and RVF in humans and livestock across different l…

Seroprevalence of Rift Valley fever virus and factors associated with exposure in south-central Uganda.

BACKGROUND: Rift Valley fever (RVF) poses a recurring public health and economic challenge in Uganda's cattle corridor. It is a mosquito-borne zoonotic disease caused by the Rift Valley fever virus (RVFV), with high livestock density, favorable rainfall patterns, and close human-animal interaction facilitating viral transmission and disease outbreaks. Although RVF outbreaks have occurred, data on human exposure in south-central Uganda remain limited. METHODS: This cross-sectional study assessed the seroprevalence and associated factors of RVFV exposure among selected communities in the greate…

Разработка высокочувствительного вертикального иммунизатора для обнаружения вируса лихорадки Рифт-Вэлли.

лихорадка Рифт-Вэлли (RVF) — инфекционная болезнь, трансмиссивная, зоонотическая, с подтвержденной историей заболеваемости и смертности как у людей, так и у животных. Вирус лихорадки Рифт-Вэлли (RVFV) отнесен центрами по борьбе с заболеваниями и их профилактике к категории высокоприоритетного биоугроза и создает серьезную национальную угрозу в связи с его легкостью распространения и потенциалом социальных потрясений. РВФ часто представляет собой фебрилальную болезнь без каких-либо конкретных симптомов, что делает обнаружение на ранней стадии особенно трудным. Поэтому крайне важно, чтобы быстра

Совпадение в аннотации оригинала
Rift Valley fever (RVF) is a vector-borne, zoonotic infectious disease with a proven history of morbidity and mortality in both humans and animals. Rift Valley fever virus (RVFV) is categorized as a high-priority biothreat agent by the Centers for Disease Control and Prevention and poses a serious national threat due to its ease of dissemination and potentia…

Detection and Molecular Characterization of Rift Valley Fever Virus in Apparently Healthy Cattle in Uganda.

Rift Valley fever (RVF) is a zoonotic disease caused by the Rift Valley fever virus (RVFV), affecting humans, livestock, and wild ruminants. This study aimed to characterize and assess the genetic diversity of RVFV strains circulating among livestock in Uganda. Blood samples were collected between January 2021 and May 2024 from apparently healthy cattle, goats, and sheep in four districts. The samples were first screened for RVFV antibodies using ELISA; antibody-positive samples were subsequently tested for viral RNA using reverse transcriptase quantitative PCR (RT-qPCR). The PCR-positive samp…

Seroprevalence of Rift Valley Fever Viruses Antibodies in Domestic Livestock in the Tahoua Region of Niger.

Rift Valley Fever (RVF) remains a significant public health and economic concern in Niger, particularly in the Tahoua region. This study aimed to update seroprevalence estimates of Rift Valley Fever Virus (RVFV) and identify high-risk areas and animal populations. A cross-sectional survey was conducted between January and May 2024, during which 615 domestic ruminants (cattle, sheep, goats, and camels) were sampled and tested for RVFV-specific antibodies using a competitive enzyme-linked immunosorbent assay (cELISA). The overall RVFV seroprevalence in the Tahoua region was 11.87% (±2.55%). Came…