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

In 2008-2009 a Rift Valley Fever (RVF) outbreak occurred in the Anjozorobe area, a temperate and mountainous area of the Madagascar highlands. The results of a serosurvey conducted in 2009 suggested recurrent circulation of RVF virus (RVFV) in this area and potential involvement of the cattle trade in RVFV circulation. The objective of this study was to describe the cattle trade network of the area and analyse the link between network structure and RVFV circulation. Five hundred and sixteen animals that tested negative in 2009 were sampled again in 2010. The 2009-2010 cattle-level seroconversi…

Identification of suitable areas for the occurrence of Rift Valley fever outbreaks in Spain using a multiple criteria decision framework.

Rift Valley fever (RVF) is a mosquito-borne viral disease that may produce a considerable impact on the economy in affected countries. In the last decades, the geographic distribution of RVF virus has increased including most of the countries in Africa, Arabia Saudi and Yemen. This situation has raised the concerns regarding its potential introduction in the European Union (EU) countries where the high number of susceptible species and competent vectors may contribute to the spread of the disease and challenge its rapid control. Thus, the identification of the areas and time periods with highe…

High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study.

BACKGROUND: The Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus. RVFV mostly causes outbreaks among domestic ruminants with a major economic impact. Human infections are associated with these events, with a fatality rate of 0.5-2%. Since the virus is able to use many mosquito species of temperate climates as vectors, it has a high potential to spread to outside Africa. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a stratified, cross-sectional sero-prevalence survey in 1228 participants from Mbeya region, southwestern Tanzania. Samples were selected from 17,872 persons who too…

Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007.

BACKGROUND: Rift Valley fever (RVF) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. METHODS: Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Kha…

Оплодотворение Клона 13, естественно смягченная авирующая изоляция вируса лихорадки Рифт-Вэлли, в Эдесе и Кулексе.

Вирус лихорадки Рифт-Вэлли продолжает вызывать серьезные вспышки острых и фебрильных заболеваний среди людей и домашних животных в Африке. Высокая патогенность вируса объясняется главным образом неструктурным белком, получаемым из сегмента S NS, который, как было показано, препятствует интерферональному выражению типа I на уровне транскрипции и подавляет синтез принимающих клеток RNA. Клон 13, естественно смягченный клон, содержащий исключение 70% в NS, является перспективным кандидатом на вакцину, поскольку он не имеет патогенности для мышей и высокоиммуногенный, ведущий к длительному иммунит

Совпадение в аннотации оригинала
Rift Valley fever virus continues to cause large outbreaks of acute and febrile illness among humans and domestic animals in Africa. The high pathogenicity of the virus is mainly due to the non-structural protein derived from the S segment NSs, which was shown to inhibit the type I interferon expression at the transcriptional level and to suppress host cell …

Laboratory safe detection of nucleocapsid protein of Rift Valley fever virus in human and animal specimens by a sandwich ELISA.

A safe laboratory procedure, based on a sandwich ELISA (sAg-ELISA), was developed and evaluated for the detection of nucleocapsid protein (NP) of Rift Valley fever virus (RVFV) in specimens inactivated at 56 degrees C for 1h in the presence of 0.5% Tween-20 (v/v) before testing. Polyclonal capture and detection immune sera were generated respectively in sheep and rabbits immunized with recombinant NP antigen. The assay was highly repeatable and specific; it detected strains of RVFV from the entire distributional range of the disease, isolated over a period of 53 years; no cross-reactivity with…

Evaluation of a commercial competitive ELISA for the detection of antibodies to Rift Valley fever virus in sera of domestic ruminants in France.

This paper describes the sensitivity and specificity of a commercial competitive ELISA for the detection of antibodies to Rift Valley fever virus (RVFV) from sera of French domestic ruminants. Field samples were collected from mainland France for the known-negative sera (cattle=191, goats=119, sheep=192) and from ruminants of a French overseas territory (Mayotte) for the known-positive sera. A cut-off value of 43% was determined for all species, achieving a sensitivity and specificity of 100% and a concordance of 100% with the species-specific threshold recommended by the manufacturer. Our res…

Mapping of the mutations present in the genome of the Rift Valley fever virus attenuated MP12 strain and their putative role in attenuation.

The MP12 attenuated strain of Rift Valley fever virus was obtained by 12 serial passages of a virulent isolate ZH548 in the presence of 5-fluorouracil (Caplen et al., 1985. Mutagen-directed attenuation of Rift Valley fever virus as a method for vaccine development. J. Gen. Virol., 66, 2271-2277). The comparison of the M segment of the two strains has already been reported by Takehara et al. (Takehara et al., 1989. Identification of mutations in the M RNA of a candidate vaccine strain of Rift Valley fever virus. Virology 169, 452-457). We have completed the comparison and found that altogether …

Effect of environmental temperature on the vector competence of Aedes taeniorhynchus for Rift Valley fever and Venezuelan equine encephalitis viruses.

Studies were conducted to determine the effect of environmental temperature on the susceptibility of Aedes taeniorhynchus mosquitoes for Venezuelan equine encephalitis (VEE) and Rift Valley fever (RVF) viruses. Mosquitoes reared at low temperature (19 degrees C) were significantly more susceptible to infection with RVF virus (infection rate = 70%, 158 of 226) than were those mosquitoes reared at 26 degrees C (infection rate = 48%, 135 of 280), regardless of the temperature at which mosquitoes were held after exposure to virus (19 or 26 degrees C). Likewise, for Ae. taeniorhynchus exposed to VE…

Complete sequences of the glycoproteins and M RNA of Punta Toro phlebovirus compared to those of Rift Valley fever virus.

The complete sequence of Punta Toro virus (Phlebovirus, Bunyaviridae) middle size (M), RNA has been determined. The RNA is 4330 nucleotides long (mol wt 1.46 X 10(6), base composition: 26.7% A, 33.6% U, 18.5% G, 21.2% C) and has 3'- and 5'-terminal sequences that, depending on the arrangement, are complementary for some 15 residues. The viral RNA codes in its viral-complementary sequence for a single primary gene product (the viral glycoprotein precursor) that is comprised of 1313 amino acids (146,376 Da) and is abundant in cysteine residues but has few potential asparagine-linked glycosylatio

Effect of extrinsic incubation temperature on the ability of Aedes taeniorhynchus and Culex pipiens to transmit Rift Valley fever virus.

Studies were conducted to examine the effects of extrinsic incubation (EI) temperature on the vector competence of Egyptian Culex pipiens and North American Aedes taeniorhynchus for Rift Valley fever (RVF) virus. Following per os exposure, infection rates in Ae. taeniorhynchus remained relatively constant at 55%, 56%, and 59% for mosquitoes held at EI temperatures of 13, 26, and 33 degrees C, respectively. In contrast, significantly fewer Cx. pipiens became infected when held at 13 degrees C (38%), than when held at 26 degrees C (75%) or 33 degrees C (91%). In both species, viral dissemination…

Hydrops amnii in sheep associated with hydranencephaly and arthrogryposis with wesselsbron disease and rift valley fever viruses as aetiological agents.

During the 1974/75 lambing season numerous reports were received from various parts of the Republic of South Africa and South West Africa of severe abdominal distension in ewes after vaccination with the attenuated Rift Valley fever and/or attenuated Wesselsbron disease vaccine. The ewes were vaccinated at different stages of gestation in spite of recommendations to the contrary, the syndrome being especially obvious in ewes immunized with one or both of these vaccines during the first trimester of pregnancy. In some of the flocks hydrops amnii was recorded in as many as 15% of the ewes. Many …

Zoonotic arbovirus infections in cattle in Mozambique with special reference to Crimean-Congo hemorrhagic fever virus (CCHFV) and rift valley fever virus (RVFV).

BACKGROUND: Arboviruses pose a great threat to public health in sub-Saharan African countries. Mozambique is located in a region that is prone to climate change-related devastation, including heavy rainfalls and severe droughts that favor the emergence of zoonotic viruses transmitted by arthropods such as Crimean-Congo hemorrhagic fever virus (Orthonairovirus haemorrhagiae, CCHFV) and Rift Valley fever virus (Phlebovirus riftense, RVFV). Both viruses are closely associated with livestock farming, including cattle, and can cause symptoms of hemorrhagic fever in humans. Available previous data s…

Attenuation of pathogenic Rift Valley fever virus strain through the chimeric S-segment encoding sandfly fever phlebovirus NSs or a dominant-negative PKR.

Rift Valley fever is a mosquito-borne zoonotic disease affecting ruminants and humans. Rift Valley fever virus (RVFV: family Bunyaviridae, genus Phlebovirus) causes abortions and fetal malformations in ruminants, and hemorrhagic fever, encephalitis, or retinitis in humans. The live-attenuated MP-12 vaccine is conditionally licensed for veterinary use in the US. However, this vaccine lacks a marker for the differentiation of vaccinated from infected animals (DIVA). NSs gene is dispensable for RVFV replication, and thus, rMP-12 strains lacking NSs gene is applicable to monitor vaccinated animals…

Climate Change, Urbanization, and the Emerging Urban Threat of Rift Valley Fever in Tropical and Subtropical Cities: A Narrative Review.

Rift Valley fever (RVF) is a climate-sensitive mosquito-borne zoonosis long regarded as a rural, pastoral disease, yet accelerating tropical urbanization and intensifying climate variability may be reshaping its epidemiology at the urban-peri-urban interface. This narrative review examines how global climate change and urban-specific climatic conditions jointly shape RVF virus (RVFV) vector habitats, transmission, and burden in tropical and subtropical cities, synthesizing 51 of 412 English-language records identified by a structured, non-systematic search of PubMed, Scopus, Web of Science, an…

Разработка анализа на основе люминекса для обнаружения антикаприпоксивируса и вируса лихорадки в долине рифта в домашних румынках.

Три члена рода каприпоксивируса (CaPV), кожного вируса (LSDV), вируса овцепокса (SPPV) и вируса козла (GTPV) имеют общие носители и районы совпадающего географического распределения с вирусом лихорадки Рифт Вэлли (RVFV). Таким образом, для обеспечения более эффективного с точки зрения затрат наблюдения за заболеваниями мы разработали и оценили результаты анализа Luminex на предмет одновременного обнаружения антител против CaPV и RVFV у домашних червей. У скота чувствительность (Se) составляла 98,7 процента, а специфичность (Sp) - 98,3 процента при обнаружении антиЛСДВ; оба диагностических пара

Совпадение в аннотации оригинала
The three members of the genus capripoxvirus (CaPV), lumpy skin disease virus (LSDV), sheeppox virus (SPPV), and goatpox virus (GTPV) have common hosts and areas of overlapping geographical distribution with Rift Valley fever virus (RVFV). Hence, to ensure more cost-effective disease surveillance we developed and evaluated a Luminex assay for the simultaneou…

Ecological and subject-level drivers of interepidemic Rift Valley fever virus exposure in humans and livestock in Northern Kenya.

Nearly a century after the first reports of Rift Valley fever (RVF) were documented in Kenya, questions on the transmission dynamics of the disease remain. Specifically, data on viral maintenance in the quiescent years between epidemics is limited. We implemented a cross-sectional study in northern Kenya to determine the seroprevalence, risk factors, and ecological predictors of RVF in humans and livestock during an interepidemic period. Six hundred seventy-six human and 1,864 livestock samples were screened for anti-RVF Immunoglobulin G (IgG). Out of the 1,864 livestock samples tested for IgG…

Rift Valley Fever Virus Infects the Posterior Segment of the Eye and Induces Inflammation in a Rat Model of Ocular Disease.

People infected with the mosquito-borne Rift Valley fever virus (RVFV) can suffer from eye-related problems resulting in ongoing vision issues or even permanent blindness. Despite ocular disease being the most frequently reported severe outcome, it is vastly understudied compared to other disease outcomes caused by RVFV. Ocular manifestations of RVFV include blurred vision, uveitis, and retinitis. When an infected individual develops macular or paramacular lesions, there is a 50% chance of permanent vision loss in one or both eyes. The cause of blinding ocular pathology remains unknown in part…

In vitro shared transcriptomic responses of Aedes aegypti to arboviral infections: example of dengue and Rift Valley fever viruses.

BACKGROUND: Arthropod borne virus infections are the cause of severe emerging diseases. Among the diseases due to arboviruses, dengue (DEN) and Rift Valley fever (RVF) are in the top ten in the list of diseases responsible of severe human cases worldwide. Understanding the effects of viral infection on gene expression in competent vectors is a challenge for the development of early diagnostic tools and may enable researchers and policy makers to better anticipate outbreaks in the next future. METHODS: In this study, alterations in gene expression across the entire Aedes aegypti genome during …