One health approach to Rift Valley fever vaccine development
Kortekaas, J.A. - \ 2014
Antiviral Research 106 (2014)24. - ISSN 0166-3542 - p. 24 - 32.
lethal virus challenge - saudi-arabia - immune-responses - rhesus macaques - mp-12 vaccine - south-africa - enzootic hepatitis - northeastern kenya - ifnar(-/-) mice - rvfv infection
Since its discovery in the 1930s, Rift Valley fever virus (RVFV) spread across the African continent and invaded the Arabian Peninsula and several islands off the coast of Southeast Africa. The virus causes recurrent outbreaks in these regions, and its continued spread is of global concern. Next-generation veterinary vaccines of improved efficacy and safety are being developed that can soon be used for the widespread vaccination of livestock. However, due to regulatory and economic challenges, vaccine manufacturers have been reluctant to develop a human vaccine. Recent innovations in veterinary vaccinology, animal models and licensing strategies can now be used to overcome these hurdles. This paper reviews the historical impact of RVFV on human health and proposes strategies to develop and license a next-generation vaccine for both animals and humans
The transmission potential of Rift Valley fever virus among livestock in the Netherlands: a modelling study
Fischer, E.A.J. ; Boender, G.J. ; Nodelijk, G. ; Koeijer, A.A. de; Roermund, H.J.W. van - \ 2013
Veterinary Research 44 (2013). - ISSN 0928-4249
west-nile-virus - adult culex-pipiens - vector competence - diptera-culicidae - mosquito diptera - vexans diptera - saudi-arabia - infection - population - dynamics
Rift Valley fever virus (RVFV) is a zoonotic vector-borne infection and causes a potentially severe disease. Many mammals are susceptible to infection including important livestock species. Although currently confined to Africa and the near-East, this disease causes concern in countries in temperate climates where both hosts and potential vectors are present, such as the Netherlands. Currently, an assessment of the probability of an outbreak occurring in this country is missing. To evaluate the transmission potential of RVFV, a mathematical model was developed and used to determine the initial growth and the Floquet ratio, which are indicators of the probability of an outbreak and of persistence in a periodic changing environment caused by seasonality. We show that several areas of the Netherlands have a high transmission potential and risk of persistence of the infection. Counter-intuitively, these are the sparsely populated livestock areas, due to the high vector-host ratios in these areas. Culex pipiens s.l. is found to be the main driver of the spread and persistence, because it is by far the most abundant mosquito. Our investigation underscores the importance to determine the vector competence of this mosquito species for RVFV and its host preference.
Rift Valley Fever Risk Map Model and Seroprevalence in Selected Wild Ungulates and Camels from Kenya
Britch, S.C. ; Binepal, Y.S. ; Ruder, M.G. ; Kariithi, H.M. ; Linthicum, K.J. ; Anyamba, A. ; Small, J.L. ; Tucker, C.J. ; Ateya, L.O. ; Oriko, A.A. ; Gacheru, S. ; Wilson, W.C. - \ 2013
PLoS ONE 8 (2013)6. - ISSN 1932-6203 - 16 p.
saudi-arabia - vertical transmission - vegetation index - african buffalo - virus - outbreak - antibody - humans - prevalence - prevention
Since the first isolation of Rift Valley fever virus (RVFV) in the 1930s, there have been multiple epizootics and epidemics in animals and humans in sub-Saharan Africa. Prospective climate-based models have recently been developed that flag areas at risk of RVFV transmission in endemic regions based on key environmental indicators that precede Rift Valley fever (RVF) epizootics and epidemics. Although the timing and locations of human case data from the 2006–2007 RVF outbreak in Kenya have been compared to risk zones flagged by the model, seroprevalence of RVF antibodies in wildlife has not yet been analyzed in light of temporal and spatial predictions of RVF activity. Primarily wild ungulate serum samples from periods before, during, and after the 2006–2007 RVF epizootic were analyzed for the presence of RVFV IgM and/or IgG antibody. Results show an increase in RVF seropositivity from samples collected in 2007 (31.8%), compared to antibody prevalence observed from 2000–2006 (3.3%). After the epizootic, average RVF seropositivity diminished to 5% in samples collected from 2008–2009. Overlaying maps of modeled RVF risk assessments with sampling locations indicated positive RVF serology in several species of wild ungulate in or near areas flagged as being at risk for RVF. Our results establish the need to continue and expand sero-surveillance of wildlife species Kenya and elsewhere in the Horn of Africa to further calibrate and improve the RVF risk model, and better understand the dynamics of RVFV transmission.
Seasonal patterns in immune indices reflect microbial loads on birds but not microbes in the wider environment
Horrocks, N.P.C. ; Matson, K.D. ; Shobrak, M. ; Tinbergen, J.M. ; Tieleman, B.I. - \ 2012
Ecosphere 3 (2012)2. - ISSN 2150-8925 - 14 p.
feather-degrading bacteria - arabian desert - saudi-arabia - life-history - trade-offs - ecological immunology - evolutionary ecology - atmospheric bacteria - airborne particles - aridity gradient
Documenting patterns in immune function is a first step to understanding immune variation, but to comprehend causes and consequences, antigen and parasite exposure that may drive such variation must be determined. We measured host-independent microbial exposure in five species of larks (Alaudidae) in the Arabian Desert by sampling ambient air for culturable microbes during late spring and winter, two periods with contrasting environmental conditions. We developed a novel technique to assay densities of microbes shed from birds, and we quantified four indices of constitutive innate immunity. Birds shed significantly more microbes during spring than winter, and all immune indices except one were also significantly higher during spring. In contrast, concentrations of airborne environmental microbes were higher in winter. Among all birds in both seasons, lysis titers were positively correlated with total densities of microbes shed from birds, suggesting that immune defenses are directed towards the microbes that birds carry, rather than microbes in the wider environment. Our findings highlight the relevance of quantifying non-specific immune challenges in ecological immunology studies, and reinforce the importance of both host-dependent and host-independent measures of antigenic pressure for understanding immune variation. Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00287.1
Rift Valley fever virus immunity provided by a paramyxovirus vaccine vector
Kortekaas, J.A. ; Boer, S.M. de; Kant, J. ; Vloet, R.P.M. ; Antonis, A.F.G. ; Moormann, R.J.M. - \ 2010
Vaccine 28 (2010)27. - ISSN 0264-410X - p. 4394 - 4401.
newcastle-disease-virus - neutralizing antibodies - envelope glycoproteins - monoclonal-antibodies - respiratory-tract - lethal infection - avian influenza - protects mice - saudi-arabia - i interferon
Rift Valley fever virus (RVFV) causes recurrent large outbreaks among humans and livestock. Although the virus is currently confined to the African continent and the Arabian Peninsula, there is a growing concern for RVFV incursions into countries with immunologically naive populations. The RVFV structural glycoproteins Gn and Cc are preferred targets in the development of subunit vaccines that can be used to control future outbreaks. We here report the production of Gn and Cc by a recombinant vaccine strain of the avian paramyxovirus Newcastle disease virus (NDV) and demonstrate that intramuscular vaccination with this experimental NDV-based vector vaccine provides complete protection in mice. We also demonstrate that a single intramuscular vaccination of lambs, the main target species of RVFV, is sufficient to elicit a neutralizing antibody response. (C) 2010 Elsevier Ltd. All rights reserved.
Interventions Against West Nile Virus, Rift Valley Fever Virus, and Crimean-Congo Hemorrhagic Fever Virus: Where Are We?
Kortekaas, J.A. ; Ergonul, O. ; Moormann, R.J.M. - \ 2010
Vector-Borne and Zoonotic Diseases 10 (2010)7. - ISSN 1530-3667 - p. 709 - 718.
boophilus-microplus - recombinant vaccine - immune-responses - neutralizing antibodies - antiviral compounds - ribavirin therapy - oral ribavirin - saudi-arabia - efficacy - protein
ARBO-ZOONET is an international network financed by the European Commission's seventh framework program. The major goal of this initiative is capacity building for the control of emerging viral vector-borne zoonotic diseases, with a clear focus on West Nile virus, Rift Valley fever virus, and Crimean-Congo hemorrhagic fever virus. To evaluate the status quo of control measures against these viruses, an ARBO-ZOONET meeting was held in Istanbul, Turkey, from 19 to 20 November 2009. The symposium consisted of three themes: (1) vaccines: new and existing ones; (2) antivirals: existing and new developments; and (3) antivector vaccines. In addition, a satellite workshop was held on epidemiology and diagnosis. The meeting brought together foremost international experts on the subjects from both within and without the ARBO-ZOONET consortium. This report highlights selected results from these presentations and major conclusions that emanated from the discussions held.
Description of plant communities on the Red Sea costal plain of Sudan
Woldewahid, G. ; Werf, W. van der; Sykora, K.V. ; Abate, T. ; Mostofa, B. ; Huis, A. van - \ 2007
Journal of Arid Environments 68 (2007)1. - ISSN 0140-1963 - p. 113 - 131.
vegetation-soil relationships - locust schistocerca-gregaria - saudi-arabia - ecology - regime - israel - jedda - negev
The coastal plains of the Red Sea constitute an important breeding area for the desert locust, Schistocerca gregaria. Vegetation analysis was undertaken in the coastal plain of Sudan to provide a frame of reference for studies on desert locust ecology and distribution. Vegetation relevés (>60 in any season) were made at peak vegetation cover during three subsequent winters, 1999¿2002. Four plant communities were distinguished by Two-Way Indicator Species Analysis. They are named by the dominant plant species: Suaeda monoica Forssk., Heliotropium spp., Panicum turgidum Forssk., and Acacia tortilis (Forssk.) Hayne. These plant communities reflect underlying differences in elevation, soil texture, water availability and land use. The spatial extent of these plant communities is mapped. The resulting vegetation classification is easy to use under field conditions and can be used for ecological studies and practical monitoring of the desert locust
Isolation of Brucella melitensis from an Arabian oryx (Oryx leucoryx)
Ostrowski, S. ; Anajariyya, S. ; Kamp, E.M. ; Bedin, E. - \ 2002
Veterinary Record 150 (2002)6. - ISSN 0042-4900 - p. 186 - 188.
saudi-arabia - wildlife