The diversity and abundance of vectors are essential parameters in the transmission dynamics of West Nile virus (WNV) between its avian reservoirs and clinically susceptible mammalian species. Knowing the determinants of vector abundance could be thus useful in preventing West Nile fever (WNF) cases and associated socio-economic impact. We designed a survey at the wildlife-livestock interface to test the hypothesis that variations in environmental favourability between anthropized and wild scenarios modulate WNV vector abundance and transmission risk.
View Article and Find Full Text PDFAvailable methods to census exophilic tick populations have limitations in estimating true population size due to their inability to capture a high proportion of the actual tick population. We currently ignore the efficacy of these methods to capture questing Hyalomma spp. ticks, vectors of the Crimean-Congo hemorrhagic fever virus.
View Article and Find Full Text PDFThe incidence of West Nile fever (WNF) is highly variable in emerging areas, making it difficult to identify risk periods. Using clinical case records has important biases in understanding the transmission dynamics of West Nile virus (WNV) because asymptomatic infections are frequent. However, estimating virus exposure in sentinel species could help achieve this goal at varying spatiotemporal scales.
View Article and Find Full Text PDFBackground: The 'snow-melt mosquito' aedes (rusticoidus) refiki is a rare species with a wide distribution in Europe that is usually defined as an aggressive mosquito for mammals, including humans. During a mosquito survey in a peri-urban area in south-central mainland Spain, adult Ae. refiki females were captured and identified by morphological traits.
View Article and Find Full Text PDFWest Nile virus (WNV) transmission rate is shaped by the interaction between virus reservoirs and vectors, which may be maximized in farm environments. Based on this hypothesis, we screened for WNV in wild birds in three scenarios with decreasing gradient of interaction with horses: (i) the farm (A); (ii) the neighborhood (A); and (iii) a wild area (A). We captured wild birds and analyzed their sera for WNV antibodies by blocking ELISA and micro-virus neutralization test.
View Article and Find Full Text PDFAn experimental infection approach was used to estimate the competence of the common mosquito, , for hepatitis E virus replication and transmission, using an isolate of hepatitis E virus genotype 3 of human origin in varying infectious doses. The experimental approach was carried out in biosafety level 2 conditions on three batches of 120 females, each using an artificial feeding system containing the virus in aliquots of fresh avian blood. Mosquitoes from each batch were collected 1, 7, 14, and 21 days post-infection (dpi) and dissected.
View Article and Find Full Text PDFThe objective of this study was to evaluate the spatial risk of exposure to Crimean-Congo haemorrhagic fever virus (CCHFV) infection of healthy blood donors in an enzootic region with a predicted risk gradient based on a virus-animal interaction risk model. We designed a cross-sectional study to test if the exposure pattern of the human population to CCHFV spatially matches the predicted risk. We randomly selected 1384 donors from different risk gradients and analyzed their sera searching for CCHFV antibodies.
View Article and Find Full Text PDFCrimean-Congo haemorrhagic fever virus (CCHFV) continues to cause new human cases in Iberia while its spatial distribution and ecological determinants remain unknown. The virus remains active in a silent tick-animal cycle to which animals contribute maintaining the tick populations and the virus itself. Wild ungulates, in particular red deer, are essential hosts for Hyalomma ticks in Iberia, which are the principal competent vector of CCHFV.
View Article and Find Full Text PDFHigh impact, mosquito-borne flaviviruses such as West Nile virus (WNV), Usutu virus (USUV), Japanese encephalitis virus (JEV), Tembusu virus (TMUV), and Bagaza/Israel turkey meningoencephalomyelitis virus (BAGV/ITV) are emerging in different areas of the world. These viruses belong to the Japanese encephalitis (JE) serocomplex (JEV, WNV, and USUV) and the Ntaya serocomplex (TMUV and BAGV/ITV). Notably, they share transmission route (mosquito bite) and reservoir host type (wild birds), and some of them co-circulate in the same areas, infecting overlapping mosquito and avian population.
View Article and Find Full Text PDFAujeszky's disease (AD) virus is enzootic in Iberian wild boar, thus posing a threat to the official eradication of AD on extensive domestic pig farms in Spain. Understanding the dynamics and drivers of ADV infection in wild boar will help prevent viral transmission at the wild boar-pig interface. This study analyses the dynamics of ADV infection in wild boar and tests relevant hypotheses in order to identify drivers of ADV infection dynamics.
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