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Vaccination for the control of Rift Valley fever in enzootic and epizootic situations.

Vaccination continues to be the most effective way to control Rift Valley fever (RVF), a zoonotic insect-borne viral disease of livestock. The irregular, cyclical and persistent nature of RVF in its occurrence in enzootic situations suggests that the vaccination strategy to be considered for these regions should be different from what is envisaged for free from risk regions. Currently available RVF vaccines have been extensively used for the control of the disease. However, these vaccines have shortcomings that have encouraged many research groups to develop new vaccine candidates that would a…

Rift valley fever in humans and animals in Mayotte, an endemic situation?

Retrospective studies and surveillance on humans and animals revealed that Rift Valley Fever virus (RVFV) has been circulating on Mayotte for at least several years. A study was conducted in 2011 to estimate the seroprevalence of RVF in humans and in animals and to identify associated risk factors. Using a multistage cluster sampling method, 1420 individuals were enrolled in the human study, including 337 children aged 5 to 14 years. For the animal study, 198 seronegative ruminants from 33 randomly selected sentinel ruminant herds were followed up for more than one year. In both studies, infor…

Ultrastructural study of Rift Valley fever virus in the mouse model.

Detailed ultrastructural studies of Rift Valley fever virus (RVFV) in the mouse model are needed to develop and characterize a small animal model of RVF for the evaluation of potential vaccines and therapeutics. In this study, the ultrastructural features of RVFV infection in the mouse model were analyzed. The main changes in the liver included the presence of viral particles in hepatocytes and hepatic stem cells accompanied by hepatocyte apoptosis. However, viral particles were observed rarely in the liver; in contrast, particles were extremely abundant in the CNS. Despite extensive lymphocyt…

Development of a novel nonhuman primate model for Rift Valley fever.

Rift Valley fever (RVF) virus (RVFV) can cause severe human disease characterized by either acute-onset hepatitis, delayed-onset encephalitis, retinitis and blindness, or a hemorrhagic syndrome. The existing nonhuman primate (NHP) model for RVF utilizes an intravenous (i.v.) exposure route in rhesus macaques (Macaca mulatta). Severe disease in these animals is infrequent, and large cohorts are needed to observe significant morbidity and mortality. To overcome these drawbacks, we evaluated the infectivity and pathogenicity of RVFV in the common marmoset (Callithrix jacchus) by i.v., subcutaneou…

Pathological studies on postvaccinal reactions of Rift Valley fever in goats.

RVF live attenuated vaccine (Smithburn strain) was evaluated by using goats as experimental animal. The results indicate that this vaccine cause severe deleterious pathological changes in liver especially in kids and causing abortion in pregnant does. The virus was seen to be propagated inside hepatic cells forming intranuclear inclusions which was also seen by E.M. Viral antigens were detected in hepatic cells, gall bladder, endothelial lining of blood vessels, leukocytes, kidneys and heart by using immunoflourescent technique. It could be concluded that the use of live attenuated vaccine of

Potential vectors of Rift Valley fever virus in the Mediterranean region.

We evaluated the ability of three mosquito species (Aedes caspius, Aedes detritus, Culex pipiens), collected in southern France and Tunisia, and of different laboratory-established colonies (Aedes aegypti, Aedes albopictus, Aedes vexans, Anopheles gambiae, Culex pipiens, Culex quinquefasciatus) to disseminate two strains of Rift Valley fever virus (RVFV), the virulent ZH548 and the avirulent Clone 13. After feeding on an infectious blood meal at 10(8.5) plaque-forming units/mL, females were maintained at 30 degrees C for 14 days. Surviving females were tested for the presence of virus on head …

The impact of climate change on the epidemiology and control of Rift Valley fever.

Climate change is likely to change the frequency of extreme weather events, such as tropical cyclones, floods, droughts and hurricanes, and may destabilise and weaken the ecosystem services upon which human society depends. Climate change is also expected to affect animal, human and plant health via indirect pathways: it is likely that the geography of infectious diseases and pests will be altered, including the distribution of vector-borne diseases, such as Rift Valley fever, yellow fever, malaria and dengue, which are highly sensitive to climatic conditions. Extreme weather events might then…

The evolving transmission pattern of Rift Valley fever in the Arabian Peninsula.

Vector-borne viruses are no respecters of international boundaries. The recent outbreak of Rift Valley fever (RVF) in the Kingdom of Saudi Arabia (KSA) and Yemen in September 2000 clearly sends a message that once pathogens cross their known geographic limits, they tend to adapt to the local ecology in order to survive and maintain transmission. This paper examines the various factors that may contribute to the establishment of RVF in the Arabian Peninsula (AP) and its possible spread to other countries. The annual influx of over 2 million pilgrims for the Hajj (annual pilgrimage for Muslims) …

Detection of Rift Valley fever virus in mosquitoes by RT-PCR.

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect Rift Valley fever (RVF) virus RNA in experimentally infected mosquitoes was developed. The specificity of the assay was evaluated with three other phleboviruses; sandfly fever Sicilian (Sabin), sandfly fever Naples (Sabin) and Punta Toro (MSP 3) viruses. The relative sensitivity of the assay, determined by using RVF virus RNA extracted from serial dilutions of virus culture, was approximately 50 plaque forming units. This sensitivity level was 100-fold higher when a nested PCR procedure was used. When the RT-PCR assay w…

[Serological survey of Rift Valley fever in sheep on the Ivory Coast].

A serological survey of Rift Valley fever was carried out in sheep in Côte-d'Ivoire. Thousand and fifty one seras collected between 1988 and 1990 in the South of the country were tested for IgG and IgM by ELISA with two objectives: determining the incidence of the Rift Valley fever and analysing the role of this virus in reproductive failure and abortion. The incidence rate was 6.85%. No difference was found between the three different geographic areas nor between the three years of the survey. Antibody prevalence increased significantly with age. The Rift Valley fever must be considered as en…

Профилактика лихорадки Рифт-Вэлли у обезьян с интерфероном-альфа.

Профилактическая и терапевтическая эффективность рекомбинантного лейкоцита А интерферона (RIFN-альфа A) и ВИЧ-инфицированного вирусом Сендай человеческого лейкоцита интерферона (HuIFN-alpha) была изучена путем внутримышечного воздействия на вирус лихорадки Рифт-Вэлли (RVFV), инфицированный резусными обезьянами. Был проконтролирован клинический, вирологический, иммунологический и геместатический параметры. Пять ежедневных прививок 5 X 10(5) продукта интерферона на килограмм веса тела, инициированных за 24 часа до или 6 часов после инфекции RVFV, предотвращающих или сильно подавляющих виремию. Н

Совпадение в аннотации оригинала
Prophylactic and therapeutic efficacy of recombinant leukocyte A interferon (rIFN-alpha A) and Sendai virus-induced human leukocyte interferon (HuIFN-alpha) administered intramuscularly to Rift Valley fever virus (RVFV)-infected rhesus monkeys was studied. Clinical, virologic, immunologic, and hemostatic parameters were monitored. Five daily inoculations of …

Оплодотворение и распространение вируса лихорадки Рифт-Вэлли в Кулексе-пипиенсе.

После поглощения вируса лихорадки Рифт-Вэлли (RVF) от 10(4.2) до 10(7.2), заразились 662 из 850 женщин-пипиен-кулек (78%). Комары, которые заразились, разделились на две разные группы: 1) те, у кого нераспространенная инфекция ограничена кишечником, и 2) те, у кого распространяется инфекция. Первая группа содержала медианный показатель 10 (3,2) ПФУ, в то время как женщины, инфицированные инфекцией, имели средний показатель 10 (5,5). Только те самки, у которых была распространенная инфекция, могли передать вирус, укусив чувствительного хомяка. Это согласуется с мезентеронным барьером для распро

Совпадение в аннотации оригинала
Following ingestion of 10(4.2) to 10(7.2) plaque-forming units (PFU) of Rift Valley fever (RVF) virus, 662 of 850 female Culex pipiens (78%) became infected. Those mosquitoes that became infected separated into two distinct groups: 1) those with a nondisseminated infection limited to the gut, and 2) those with a disseminated infection. The former group conta…

A serological survey of Rift Valley fever antibodies in the northern Sinai.

In the aftermath of an extensive Egyptian Rift Valley fever (RVF) epidemic during 1977-78, RVF activity in the adjacent Sinai peninsula has been inferred from the presence of haemagglutination-inhibition (HI) antibodies in sera from indigenous humans and rodents. We attempted to confirm these findings by HI testing of sera from Israeli soldiers serving in the region of the El Arish Wadi system in the Sinai, and from indigenous rodents. Six of 199 human sera (3.0%) and two of 88 rodent sera (2.3%) were positive, but none reacted in the more specific plaque-reduction neutralization test. We conc…