Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease endemic to Africa and the Arabian Peninsula. High rates of abortion among infected ruminants and hemorrhagic fever in infected ...humans are major public health concerns. Commercially available veterinary RVF vaccines are important for preventing the spread of the Rift Valley fever virus (RVFV) in endemic countries; however, RVFV outbreaks continue to occur frequently in endemic countries in the 21st century. In the U.S., the live-attenuated MP-12 vaccine has been developed for both animal and human vaccination. This vaccine strain is well attenuated, and a single dose induces neutralizing antibodies in both ruminants and humans. Areas covered: This review describes scientific evidences of MP-12 vaccine efficacy and safety, as well as MP-12 variants recently developed by reverse genetics, in comparison with other RVF vaccines. Expert commentary: The containment of active RVF outbreaks and long-term protection from RVF exposure to infected mosquitoes are important goals for RVF vaccination. MP-12 vaccine will allow immediate vaccination of susceptible animals in case of an unexpected RVF outbreak in the U.S., whereas MP-12 vaccine may be also useful for the RVF control in endemic regions.
Porphyry and skarn deposits in the middle Yangtze Valley within the Northern Yangtze Craton have a combined tungsten resource of ~3milliontonnes (Mt) and represent one of the most important tungsten ...regions in the world. The Dahutang porphyry tungsten deposit, with reserves of >1Mt, is one of the largest deposits. Uranium–Pb analyses for the ore-related granitoids yield ages of 147.4±0.58Ma–148.3±1.9Ma for porphyritic biotite granite, 144.7±0.47Ma–146.1±0.64Ma for fine-grained granite, and 143.0±0.76Ma–143.1±1.2Ma for granite porphyry, a progressive youngling of ages that is consistent with field observations. Geochemical data show that the three types of granite are characterized by enrichments in Rb, Pb, and U, and depletion in Ba, Nb, P, and Ti, with ASI molar Al2O3/(CaO+Na2O+K2O)>1.1 that is characteristic of a peraluminous melt. The P2O5 contents of the granites are 0.13–0.37% and have a positive correlation with SiO2, and they are thus S-type intrusions. They exhibit initial 87Sr/86Sr of 0.721 to 0.731 and εNd(t) of −5.06 to −7.99 for porphyritic biotite granite, 0.7196 to 0.7289 and −6.29 to −6.74 for fine-grained granite, and 0.7153 to 0.7365 and −5.09 to −7.64 for granite porphyry. Chondrite-normalized rare earth element (REE) patterns for the granites are characterized by enrichment in the light REE and a strong negative Eu anomaly, indicating that they were derived from the Proterozoic pelitic and psammitic basement strata and experienced strong fractional crystallization of plagioclase. Our ca. 150–140Ma age for the Dahutang S-type magmatism and W mineralization is identical to that of the I-type magmatism related to Cu–Au–Mo–Fe-bearing porphyry and skarn deposits along the middle to lower Yangtze River Valley. We propose that the latest Jurassic to earliest Cretaceous granitoids and ores formed during a tearing of the subducting Izanagi slab, which caused the upwelling of asthenosphere and resulting mantle–crust interaction. The S-type granitoids and related W ore systems resulted from the re-melting of the Proterozoic crust, whereas the I-type granitic rocks and related ores are attributed to the partial melting of the subducted slab.
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•Petrogenesis of the granitoids within Dahutang tungsten deposit, South-Central China.•Zircon U-Pb ages for granitoids obtained range from 147.4±0.58 Ma to 143.0±0.76 Ma.•Petrochemical and Sr-Nd data indicate the granitoids are remelted from the crust.•Model for the petrogenesis and related mineraliztion of the deposit was proposed.
Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006-07. This study investigates the spatial and ...temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies.
A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district.
RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977-79, 1989, 1997-98 and 2006-07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR = 6.14, CI: 1.96, 19.28), total amount of rainfall of >405.4 mm (OR = 12.36, CI: 3.06, 49.88), soil texture (clay OR = 8.76, CI: 2.52, 30.50, and loam OR = 8.79, CI: 2.04, 37.82).
RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture.
Groundwater depletion is an important problem driven by population growth, land use and land cover (LULC) change, climate change, and other factors. Groundwater depletion generates water stress and ...encourages unstainable resource use. The aim of this study is to determine how population growth, LULC change, and climate change relate to groundwater depletion in the Alto Atoyac sub-basin, Oaxaca, Mexico. Twenty-five years of dry season water table data from 1984 to 2009 are analyzed to examine annual groundwater depletion. Kriging is used to interpolate the region’s groundwater levels in a geographic information system (GIS) from mapped point measurements. An analysis of remotely sensed data revealed patterns of LULC change during a 34-year (1986–2018) period, using a supervised, machine-learning classification algorithm to calculate the changes in LULC. This analysis is shown to have an 85% accuracy. A global circulation model (GFDL-CM3) and the RCP4.5 and RCP8.5 scenarios were used to estimate the effects of climate change on the region’s groundwater. Estimates of evapotranspiration (using HELP3.5 code) and runoff (USDA-SCS-CN), were calculated. Since 1984, the region’s mean annual temperature has increased 1.79 °C and urban areas have increased at a rate of 2.3 km2/year. Population growth has increased water consumption by 97.93 × 106 m3/year. The volume of groundwater is shrinking at a rate of 284.34 × 106 m3/year, reflecting the extreme pressure on groundwater supply in the region. This research reveals the nature of the direct impacts that climate change, changing LULCs, and population growth have in the process of groundwater depletion.
DNA-paramagnetic silica bead aggregation in a rotating magnetic field facilitates the quantification of DNA with femtogram sensitivity, but yields no sequence-specific information. Here we provide an ...original description of aggregation inhibition for the detection of DNA and RNA in a sequence-specific manner following loop-mediated isothermal amplification (LAMP). The fragments generated via LAMP fail to induce chaotrope-mediated bead aggregation; however, due to their ability to passivate the bead surface, they effectively inhibit bead aggregation by longer 'trigger' DNA. We demonstrate the utility of aggregation inhibition as a method for the detection of bacterial and viral pathogens with sensitivity that approaches single copies of the target. We successfully use this methodology for the detection of notable food-borne pathogens Escherichia coli O157:H7 and Salmonella enterica, as well as Rift Valley fever virus, a weaponizable virus of national security concern. We also show the concentration dependence of aggregation inhibition, suggesting the potential for quantification of target nucleic acid in clinical and environmental samples. Lastly, we demonstrate the ability to rapidly detect infectious pathogens by utilizing a cell phone and custom-written application (App), making this novel detection modality fully portable for point-of-care use.
Rift Valley fever (RVF) is an important viral zoonotic disease in Africa with periodic outbreaks associated with severe disease, death, and economic hardship. During the 2006-2007 outbreaks in ...Eastern Africa, postmortem and necropsy tissue samples from 14 animals and 20 humans clinically suspected of RVF were studied with histopathologic evaluation and immunohistochemical (IHC) assays. Six animal and 11 human samples had IHC evidence of Rift Valley fever virus (RVFV) antigens. We found that extensive hepatocellular necrosis without prominent inflammatory cell infiltrates is the most distinctive histopathologic change in liver tissues infected with RVFV. Pathologic studies on postmortem tissue samples can help establish the diagnosis of RVF, differentiating from endemic diseases with clinical manifestations similar to RVF, such as malaria, leptospirosis, or yellow fever.
Rift Valley fever (RVF) is an important viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. The disease is of concern to international agricultural ...and public health communities. The RVFV MP-12 strain has been the most safety tested attenuated vaccine strain; thus it is being considered as a potential vaccine for the US national veterinary stockpile. This study was designed to establish safety protocols for large animal research with virulent RVF viruses, establish a target host immune response baseline using RVF MP-12 strain, and independently evaluate this strain as a potential US emergency response vaccine. Ten, approximately four month-old lambs and calves were vaccinated with RVF MP-12 strain; two additional animals per species provided negative control specimens. The animals were monitored for clinical and immune response, fever, and viremia. Two animals per species were sacrificed on 2, 3, 4, 10 and 28 days post infection and full necropsies were performed for histopathological examination. No clinical or febrile responses were observed in this study. The onset and titer of the immune response is discussed. There was no significant histopathology in the lambs; however, 6 out of 10 vaccinated calves had multifocal, random areas of hepatocellular degeneration and necrosis. RVF MP12 antigen was detected in these areas of necrosis by immunohistochemistry in one calf. This study provides independent and baseline information on the RVF MP-12 attenuated vaccination in vaccine relevant age target species and indicates the importance of performing safety testing on vaccine relevant aged target animals.
Forests of Belongingexamines the history and ongoing transformation of ethnic and social relationships among four distinct communities--Bangando, Baka, Bakwéle, and Mbomam--in the Lobéké forest ...region of southeastern Cameroon. By slotting forest communities into ecological categories such as "hunters" and "gatherers," previous analyses of social relationships in tropical forests have resulted in binary frameworks that render real-life relationships invisible and that have perpetuated correspondingly misleading labels, such as "pygmy." Through rich descriptive detail resulting from field work among the Bangando, Stephanie Rupp illustrates the complexity of social ties among groups and individuals, and their connections with the natural world. She demonstrates that social and ethno-ecological relations in equatorial African forests are nuanced, contested, and shifting, and that the intricacy of these links must be considered in the design and implementation of aid policies and strategies for conservation and development.
Human behavioral factors have been found to be central in the transmission of Rift Valley fever. Consumption of contaminated meat and milk in particular have been identified as one of the key risk ...factors for the transmission of Rift Valley fever in humans. In pastoral communities, livestock is the main source of livelihood from which many benefits such as food as well as economic and cultural services are derived. Zoonotic diseases therefore have a great impact on pastoral communities livelihoods. However, lay perceptions regarding the transmission of these diseases including Rift Valley fever hampers their effective control. This study investigated the lay perceptions of risks for Rift Valley fever transmission in a pastoral community in northeastern Kenya.
A qualitative study was carried out in Ijara district, Kenya which was one of the hotspots of Rift Valley during the 2006/2007 outbreak. Data were collected using focus group discussions and narratives guided by checklists. Eight focus group discussions consisting of 83 participants and six narratives were conducted. Data was transcribed, coded and analysed according to Emergent themes.
The participants reported that they had experienced Rift Valley fever in their livestock especially sheep and in humans both in 1997/1998 and 2006/2007. However, they believed that infections in humans occurred as a result of mosquito bites and had little to do with their consumption of meat, milk and blood from infected livestock. The participants in this study indicated that they had heard of the risks of acquiring the disease through consumption of livestock products but their experiences did not tally with the information they had received hence to them, Rift Valley fever was not transmissible through their dietary practices.
Though the communities in this region were aware of Rift Valley fever, they did not have elaborate information regarding the disease transmission dynamics to humans. To avoid misconception about transmission of the disease, intervention strategies, require to be accompanied by comprehensive explanations of the dynamics of its transmission. It is necessary to develop appropriate interventions that take into consideration, lay perceptions of risk factors for the disease and communities' livelihood strategies.
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