Результаты поиска

Seroprevalence and risk factors for Q fever and Rift Valley fever in pastoralists and their livestock in Afar, Ethiopia: A One Health approach.

BACKGROUND: Coxiella burnetii, the causative agent of Q fever, and Rift Valley fever virus are two under-researched zoonotic pathogens in Ethiopia. Potential outbreaks of these diseases, in light of the high dependency of nomadic pastoralists on their livestock, poses a risk to both human and animal health in addition to risking the pastoralists livelihoods. Our study aimed to determine the seroprevalence and associated risk factors for Q fever and Rift Valley fever in pastoral communities in the Afar region of north-eastern Ethiopia. METHODOLOGY/PRINCIPAL FINDINGS: This cross-sectional study…

Hyperendemicity of Rift Valley Fever in Southwestern Uganda Associated With the Rapidly Evolving Lineage C Viruses.

BACKGROUND: Recent Rift Valley fever (RVF) epidemiology in the eastern Africa region is characterized by widening geographic range and increasing frequency of small disease clusters. Here we conducted studies in the southwestern (SW) Uganda region that has since 2016 reported increasing RVF activities. METHODS: A 22-month long hospital-based study in 3 districts of SW Uganda targeting patients with acute febrile illness or unexplained bleeding was followed by a cross-sectional population-based human-animal survey. We then estimated RVF virus (RVFV) force of infection and yearly cases using ag…

Epidemiological and molecular characterization of Rift Valley fever outbreak in livestock in Burundi, May - November 2022.

An outbreak of Rift Valley fever (RVF) was officially reported for the first time in Burundi on 10th May 2022. The outbreak originated in the northern provinces and progressively spread to other regions of the country. This study presents (i) epidemiological investigations that were carried out through a countrywide emergency response and (ii) the characterization of the genotype of the RVF virus that caused the outbreak through phylogenetic analyses. Field teams visited each affected farm, collected data on observed syndromes, species and number of animals affected, farm's locations, and herd…

Sensitivity analysis of factors influencing the ecology of mosquitoes involved in the transmission of Rift Valley fever virus.

Vector-borne diseases are a major global health concern, with Rift Valley fever (RVF) serving as a key example due to its impact on both human and animal health. Predicting and controlling such diseases requires understanding how environmental factors shape mosquito ecology. Due to mosquito abundance, distribution, and behavior being influenced by ecological conditions, identifying the drivers of these dynamics is essential for anticipating transmission risk. This study aims to assess the sensitivity of ecological factors governing the ecology of mosquitoes, using a deterministic, compartmenta…

Use of Rift Valley Fever Virus Expressing NanoLuc Luciferase for the Assessment of Neutralizing Antibodies and Antivirals.

Rift Valley fever (RVF) is an arboviral zoonotic disease affecting many African countries with the potential to spread to other geographical areas. In this chapter we describe the use of a replication-competent recombinant (r)RVFV expressing NanoLuc Luciferase (Nluc) for in vitro studies. The determination of parameters such as neutralizing antibodies in serum samples, or the antiviral activity of drugs is usually carried out using standard assays based on the assessment of cytopathic effect on cell cultures. The use of a virus encoding a traceable reporter protein allows to correlate the pres…

The Dissemination of Rift Valley Fever Virus to the Eye and Sensory Neurons of Zebrafish Larvae Is Stat1-Dependent.

The Rift Valley fever virus (RVFV) causes haemorrhagic fever, encephalitis, and permanent blindness and has been listed by the WHO as a priority pathogen. To study RVFV pathogenesis and identify small-molecule antivirals, we established a novel In Vivo model using zebrafish larvae. Pericardial injection of RVFV resulted in ~4 log10 viral RNA copies/larva, which was inhibited by the antiviral 2'-fluoro-2'-deoxycytidine. The optical transparency of the larvae allowed detection of RVFVeGFP in the liver and sensory nervous system, including the optic tectum and retina, but not the brain or spinal …

Genomic Epidemiology of Rift Valley Fever Virus Involved in the 2018 and 2022 Outbreaks in Livestock in Rwanda.

Rift Valley fever (RVF), a mosquito-borne transboundary zoonosis, was first confirmed in Rwanda's livestock in 2012 and since then sporadic cases have been reported almost every year. In 2018, the country experienced its first large outbreak, which was followed by a second one in 2022. To determine the circulating virus lineages and their ancestral origin, two genome sequences from the 2018 outbreak, and thirty-six, forty-one, and thirty-eight sequences of small (S), medium (M), and large (L) genome segments, respectively, from the 2022 outbreak were generated. All of the samples from the 2022…

Seroprevalence of Rift Valley fever and associated risk factors in livestock of Afar Region, northeastern Ethiopia.

Rift Valley fever (RVF) is one of the emerging arthropod-borne zoonotic viral diseases with serious public and economic significance in the livestock and human populations of East Africa. Its epidemiology is inadequately recognized in Ethiopia. A cross-sectional study was conducted to investigate the seroprevalence and potential risk factors of RVF in domestic livestock of Amibara and Haruka districts of the Afar Region, northeastern Ethiopia. A total of 736 (224 cattle, 121 goats, 144 sheep, 155 camels and 92 donkeys) blood samples were collected, and serum extracted and tested using competit…

Mechanistic insight into the efficient packaging of antigenomic S RNA into Rift Valley fever virus particles.

Rift Valley fever virus (RVFV), a bunyavirus, has a single-stranded, negative-sense tri-segmented RNA genome, consisting of L, M and S RNAs. An infectious virion carries two envelope glycoproteins, Gn and Gc, along with ribonucleoprotein complexes composed of encapsidated viral RNA segments. The antigenomic S RNA, which serves as the template of the mRNA encoding a nonstructural protein, NSs, an interferon antagonist, is also efficiently packaged into RVFV particles. An interaction between Gn and viral ribonucleoprotein complexes, including the direct binding of Gn to viral RNAs, drives viral …

Outbreak of Rift Valley Fever Retinitis in Rwanda: Novel Imaging Findings and Response to Treatment with Corticosteroids.

PURPOSE: To describe the clinical and epidemiological characteristics of the first epidemic of Rift Valley Fever retinitis in Rwanda and to report novel imaging findings and a possible role for corticosteroids. METHODS: Retrospective analysis of all patients who presented with presumed Rift Valley Fever retinitis at the Rwanda Charity Eye Hospital over a period of 4 months in 2022. Multimodal images are reviewed including optical coherence tomography, fluorescein angiography, color, infrared, red-free, and autofluorescence photography. RESULTS: The newly identified arciform hyporeflective pa…

Обследование на основе широкого участия факторов риска и путей воздействия лихорадки долины Рифт в скотоводческих и агропастбищных общинах Уганды.

Для оценки знаний скотоводов и агропасториалистов о лихорадке Рифт-Вэлли (RVF) в период с января по февраль 2022 года в Напаке, Бутебо, Исингиро и Лянтонде, Уганда, были проведены эпидемиологические исследования с участием 215 скотоводов и 27 основных информаторов. Скотоводы во всех четырех округах были знакомы с РВФ и даже имели местные названия или описания. Пасторалисты и агропасторалисты обладали ценными знаниями о клинических характеристиках РВФ и таких эпидемиологических факторах риска, как наличие инфицированных комаров, проживание в районах, подверженных наводнениям, и чрезмерное колич

Совпадение в аннотации оригинала
To assess pastoralists' and agropastoralists' knowledge on Rift Valley fever (RVF), participatory epidemiological studies were conducted with 215 livestock keepers and 27 key informants in Napak, Butebo, Isingiro and Lyantonde districts, Uganda, between January and February 2022. Livestock keepers in all four districts had knowledge of RVF and even had local…

Serological evidence of the circulation of the Rift Valley fever virus in sheep and goats slaughtered in Yaoundé, Cameroon.

BACKGROUND: Rift Valley fever (RVF) is an emerging mosquito-borne haemorrhagic fever disease capable of causing severe outbreaks with high mortality and morbidity in human, livestock, and wildlife species, particularly in Africa. The onset of the disease in humans is often preceded by epizootic circulation in animals. Therefore, this study was conducted to investigate the seroprevalence of Rift Valley fever virus (RVFV) infection in animals slaughtered in the "Marché huitième" slaughterhouse in Yaoundé, Cameroon. METHODS: A cross-sectional study was conducted at the "Marché huitième" slaughte…

Congenital Rift Valley fever in Sprague Dawley rats is associated with diffuse infection and pathology of the placenta.

Rift Valley fever (RVF) is a disease of animals and humans associated with abortions in ruminants and late-gestation miscarriages in women. Here, we use a rat model of congenital RVF to identify tropisms, pathologies, and immune responses in the placenta during vertical transmission. Infection of late-gestation pregnant rats resulted in vertical transmission to the placenta and widespread infection throughout the decidua, basal zone, and labyrinth zone. Some pups from infected dams appeared normal while others had gross signs of teratogenicity including death. Histopathological lesions were de…

The challenging management of Rift Valley Fever in humans: literature review of the clinical disease and algorithm proposal.

Rift Valley Fever (RVF) is an emerging zoonotic arbovirus with a complex cycle of transmission that makes difficult the prediction of its expansion. Recent outbreaks outside Africa have led to rediscover the human disease but it remains poorly known. The wide spectrum of acute and delayed manifestations with potential unfavorable outcome much complicate the management of suspected cases and prediction of morbidity and mortality during an outbreak. We reviewed literature data on bio-clinical characteristics and treatments of RVF human illness. We identified gaps in the field and provided a prac…

The One Health Approach is Necessary for the Control of Rift Valley Fever Infections in Egypt: A Comprehensive Review.

Rift Valley fever (RVF) is an emerging transboundary, mosquito-borne, zoonotic viral disease caused high morbidity and mortality in both human and ruminant populations. It is considered an important threat to both agriculture and public health in African and the Middle Eastern countries including Egypt. Five major RVF epidemics have been reported in Egypt (1977, 1993, 1994, 1997, and 2003). The virus is transmitted in Egypt by different mosquito's genera such as Aedes, Culex, Anopheles, and Mansonia, leading to abortions in susceptible animal hosts especially sheep, goat, cattle, and buffaloes…

Vector competence of Culex antennatus and Anopheles coustani mosquitoes for Rift Valley fever virus in Madagascar.

Culex antennatus (Diptera: Culicidae), Anopheles coustani (Diptera: Culicidae) and Anopheles squamosus/cydippis were found to be infected with Rift Valley fever virus (RVFV) during an epidemic that occurred in 2008 and 2009 in Madagascar. To understand the roles played by Cx. antennatus and An. coustani in virus maintenance and transmission, RVFV vector competence was assessed in each species. Mosquito body parts and saliva of mosquitoes that fed on RVFV-infected blood were tested for RVFV using real-time quantitative polymerase chain reaction (RT-qPCR) assays. Overall, viral RNA was detected …

Competence of mosquitoes native to the United Kingdom to support replication and transmission of Rift Valley fever virus.

BACKGROUND: Rift Valley fever phlebovirus (RVFV) is a mosquito-borne arbovirus causing severe disease in humans and livestock. It is endemic in Africa and spread to the Arabian Peninsula in 2000 raising concerns it could emerge in Europe. The ability of temperate mosquitoes from the United Kingdom (UK) to support replication and transmission of RVFV is unknown. METHODS: In this study, two colonised lines of Culex pipiens, wild-caught Aedes detritus and Ae. rusticus from the UK were infected with pathogenic strains of RVFV to assess their vector competence. Mosquitoes were offered artificial b…

Seroprevalence and Virus Activity of Rift Valley Fever in Cattle in Eastern Region of Democratic Republic of the Congo.

Rift Valley fever (RVF) is a zoonotic disease that is characterized by periodic and severe outbreaks in humans and animals. Published information on the occurrence of RVF in domestic animals is very scarce in the Democratic Republic of the Congo (DRC). To assess possible circulation of Rift Valley fever virus (RVFV) in cattle in the eastern province of DRC, 450 sera collected from cattle in North Kivu, South Kivu, and Ituri provinces were analyzed using the enzyme-linked immunosorbent assay (ELISA), for the detection of viral Immunoglobulin (Ig) G and M, and reverse transcriptase polymerase ch…