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Передача вируса лихорадки Рифт-Вэлли взрослыми комарами после поглощения вируса личинками.

Мы изучили способность Culex pipiens, Aedes Crossluteolus и Ae. mcintoshi, подвергаясь воздействию личинок в печени от вируса лихорадки Рифт-Вэлли (RVF), стать инфицированным и трансстадиально передавать вирус взрослым, а взрослым передавать вирус путем укуса хомякам. После воздействия личинок 9% (5/54) взрослых Сх. пипиенов и 8% (38/505) видов взрослых ээ. (Неомеланиконион) были заражены. Все инфицированные Cx. pipiens и около половины инфицированных Ae. Crocluteolus и Ae. mcintoshi перенес вирус RVF, укусив хомяков. Показатели передачи инфекции от комаров, инфицированных в устной форме в кач

Совпадение в аннотации оригинала
We studied the ability of Culex pipiens, Aedes circumluteolus, and Ae. mcintoshi, exposed as larvae to liver tissue from a Rift Valley fever (RVF) virus-infected hamster, to become infected and transstadially transmit virus to the adult and for the adults to transmit virus by bite to hamsters. After exposure as larvae, 9% (5/54) of adult Cx. pipiens and 8% (…

Experimental infection and protection of lambs with a minute plaque variant of Rift Valley fever virus.

The injection of a single dose containing 5 X 10(3) plaque forming units (PFU) of a minute plaque variant of Rift Valley fever virus (RVFV) into two susceptible lambs resulted in no detectable viremia, pyrexia or clinical signs of disease. Immunization with the minute plaque variant induced neutralizing antibody as early as seven days postinoculation; however, no complement fixing antibodies were detected. Lambs immunized in this manner were protected when challenged with an infectious dose containing 1 X 10(3) PFU of wild type RVFV. These data indicate that the minute plaque variant may hold …

[Rift valley fever and Zinga virus: a pathogenic arbovirus in man and animal new for Madagascar].

Virus Zinga strains have been isolated from several pools of mosquitoes collected in Perinet area, 130 km far from Tananarive, at the Institut Pasteur of Madagascar in 1980. Although this virus is pathogenic for man, it seemed to give only a mild illness and did not appear to constitute a problem of Public Health. But today it is seen in quite a different way; since the WHO Center for Arbovirus Reference and Research of New Haven has shown the serologic identity between virus Zinga and an another arbovirus, Rift Valley Fever virus. This latter is in fact very pathogenic for man and domestic an…

Rift Valley fever vaccine--antibody and immune response in cattle to a live and an inactivated vaccine.

In a study of the response in cattle to a live and an inactivated Rift Valley fever (RVF) vaccine prepared from cell cultures infected with RVF virus, the effects of varying doses and combinations of these vaccines were compared. The antibody response to a primary injection of either vaccines was poor when measured by the serum virus neutralization test (SVN) and the haemagglutination-inhibition test (HI) but a booster dose of inactivated vaccine evoked a good anamnestic response in cattle previously injected with either of these vaccines. Cattle vaccinated with the live vaccine but negative t…

Evaluation of factors related to growth of Rift Valley fever virus in suspended cell cultures.

The effect of several controlled variables on the peak titer and fold increase of Rift Valley fever virus grown in suspension culture on two variants of Earle's L cell, L-DR and L-MA clone 1-1, was studied. No significant amount of cell-associated virus was found at 24 hr, indicating a release of virus soon after its formation. Mild sonic treatment of the virus produced in serum-free medium increased the infective titer about 10x. This difference was not observed with virus produced in medium supplemented with serum. Peak titer was not affected by medium used during the infection period, by mu…

Reprint of "Epidemiology of brucellosis, Q Fever and Rift Valley Fever at the human and livestock interface in northern Côte d'Ivoire".

Northern Côte d'Ivoire is the main livestock breeding zone and has the highest livestock cross-border movements in Côte d'Ivoire. The aim of this study was to provide updated epidemiological data on three neglected zoonotic diseases, namely brucellosis, Q Fever and Rift Valley Fever (RVF). We conducted three-stage cross-sectional cluster surveys in livestock and humans between 2012 and 2014 in a random selection of 63 villages and a sample of 633 cattle, 622 small ruminants and 88 people. We administered questionnaires to capture risk factors and performed serological tests including the Rose …

Temporal distribution and spatial pattern of abundance of the Rift Valley fever and West Nile fever vectors in Barkedji, Senegal.

The temporal distribution and spatial pattern of abundance of mosquito vectors of Rift Valley fever (RVf) and West Nile fever (WNf) were studied during the 2005 and 2006 rainy seasons at Barkedji, Senegal. Mosquitoes were collected every two weeks with CDC light traps with dry ice at 79 sites including temporary ponds, barren, shrubby savannah, wooded savannah, steppes, and villages at different distances (between 0 and 600 m) from the nearest pond. The temporal distributions of these vectors varied between 2005 and 2006 and were positively correlated with rainfall for Aedes (Aedimorphus) vexa…

[Recombinant expression of rift valley fever virus nucleocapsid protein and generation of rabbit polyclonal antibodies].

Objective Prokaryotic expression and purification of the Rift Valley fever virus (RVFV) nucleocapsid protein (NP) were performed to establish a basis for serum NP antibody detection and to produce specific polyclonal antibodies against NP. Methods The constructed pET28a-ZH501-NP prokaryotic expression plasmid was transformed into BL21(DE3) competent cells, and the expression of the recombinant protein NP was induced by isopropyl-β-D-thiogalactoside (IPTG). The recombinant protein NP was purified using HisTrapTM HP and mixed with Freund's complete and incomplete adjuvants to immunize New Zealan…

Opportunities and challenges for countermeasures against Rift Valley fever virus: A quintessential One Health pathogen.

Rift Valley fever virus (RVFV) is a zoonotic arbovirus transmitted by a wide range of mosquito vectors present across the African continent. RVFV has resulted in large-scale epidemics in East, West, southern, and northern Africa with additional epidemics affecting the Arabian Peninsula, Mayotte, and Comoros. In some areas, rather than large-scale isolated outbreaks, RVFV causes a fluctuating low-level endemic burden affecting livestock populations by resulting in pregnancy loss and significant production losses. RVFV risk extends into the human population when it is transmitted either by vecto…

PROJECTING CLIMATE CHANGE IMPACTS ON INTER-EPIDEMIC RISK OF RIFT VALLEY FEVER ACROSS EAST AFRICA.

BACKGROUND: Rift Valley fever (RVF) is a zoonotic disease that causes sporadic, multi-country epidemics. However, RVF virus (RVFV) also circulates during inter-epidemic periods. There is limited understanding of how climate change will affect inter-epidemic RVF. Here, we project inter-epidemic RVF risk under future climate scenarios, focusing on the East African countries of Kenya, Tanzania, and Uganda. METHODS: We combined data on inter-epidemic RVF outbreaks and spatially-explicit predictor variables to build a predictive model of inter-epidemic RVF risk. We validated our model using RVFV s…

Humoral immunity is sufficient to protect mice against Rift Valley fever encephalitis following percutaneous exposure.

In humans, Rift Valley fever virus (RVFV) infection typically presents as a self-limiting febrile illness but can cause severe complications. Neurological disease manifestations are particularly concerning as they are associated with increased mortality and long-term morbidity. This study demonstrated that vaccination with live attenuated RVFV was effective in preventing central nervous system (CNS) disease in the CC057/Unc mouse model of late-onset RVF encephalitis. Vaccine candidates (ΔNSs and ΔNSsΔNSm) were safe and immunogenic and elicited both RVFV-specific humoral and cellular immunity. …

Localized Rift Valley fever virus persistence explains epidemic and interepidemic dynamics and guides control strategies.

Rift Valley fever (RVF) is an emerging disease with devastating impacts on livestock health and livelihoods. The risk of RVF virus (RVFV) emergence in new regions and the effectiveness of a strategy for preventing establishment are impacted by how infection persists at local scales. Multiple mechanisms have been proposed for its persistence in regions prone to epidemics, including maintenance via transovarial transmission (TOT) but whether and how TOT can support local persistence is not well understood. Through the development of host- and multi-vector climate-driven simulation models to recr…

Vaccine strains of Rift Valley fever virus exhibit attenuation at the maternal-fetal placental interface.

Rift Valley fever virus (RVFV) infection causes abortions in ruminant livestock and is associated with an increased likelihood of miscarriages in women. Using sheep and human placenta explant cultures, we sought to identify tissues at the maternal-fetal interface targeted by RVFV. Sheep villi and fetal membranes were highly permissive to RVFV infection resulting in markedly higher virus titers than human cultures. Sheep cultures were most permissive to wild-type RVFV and ΔNSm infection, while live attenuated RVFV vaccines (LAVs; MP-12, ΔNSs, and ΔNSs/ΔNSm) exhibited reduced replication. The hu…