Fig 1 - available from: Parasites & Vectors
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The device used to trap mosquitoes attracted by falcon broods. The upper side of the plastic sheet is covered with an adhesive gel that traps insects landing on the surface. The sheets were left in this position for 24 h
Source publication
Background
Avian host species have different roles in the amplification and maintenance of West Nile virus (WNV), therefore identifying key taxa is vital in understanding WNV epidemics. Here, we present a comprehensive case study conducted on red-footed falcons, where host-vector, vector-virus and host-virus interactions were simultaneously studied...
Citations
... This suggests that Anas platyrhynchos Mallard Czech Republic [9] Spain [46,100] Anas strepera Gadwall Czech Republic [9] Spain [100] Anas sp. Duck (unspecified) China [53] France [30] Spain [101] Anser anser Greylag goose Czech Republic [9] Spain [46,100] Ardea cinerea Grey heron Spain [100] Branta canadensis Canada goose Spain [100] Chen caerulescens Snow goose Spain [100] Circus aeruginosus Western Marsh harrier Czech Republic [9] Cygnus olor Mute swan United Kingdom [28] Egretta garzetta Little egret Spain [100] Emberiza citrinella Yellowhammer Czech Republic [9] Erithacus rubecula European robin Czech Republic [9] Falco vespertinus Red-footed falcon Hungary [96] Fringilla coelebs Eurasian chaffinch Czech Republic [9] Gallus gallus Red junglefowl Spain [46,100] Gallus sp. Chicken (unspecified) Russia [87] Hirundo rustica Barn swallow Czech Republic [9] United Kingdom [28] Muscicapa striata Spotted flycatcher Czech Republic [9] Nycticorax nycticorax Black-crowned night heron Czech Republic [9] Parus caeruleus Blue tit Czech Republic [9] Parus major Great tit Czech Republic [9] Passer domesticus House sparrow Czech Republic [9] Sturnus vulgaris Common starling Czech Republic [9] Tadorna ferruginea Ruddy shelduck Spain [100] Tadorna tadorna Common shelduck Spain [100] Turdus merula Eurasian blackbird Czech Republic [9] Unspecified Unspecified Spain [34,46] Mammal (Mammalia) Bos taurus Cow China [33] Russia [87] Canis familiaris Dog Italy [91] Russia [87] Equus caballus Horse France [30] Russia [87] Homo sapiens Human Russia [87] UK [51] Sus domesticus Pig China [33] Unspecified Unspecified Spain [34,46] Reptile (Reptilia) Unspecified Unspecified Spain [34] the feeding preference of Cx. modestus depends on host abundance and availability in their current habitats. ...
... Wild Cx. modestus have been captured using a variety of different trapping methods, including HLCs [32,51,52], BG-Sentinel traps baited with CO 2 [4,13,59,93], CDC light traps baited with CO 2 [12,15,26,52,53,61], Mosquito Magnet Pro traps [19,28,29], and larval dipping [18,19,21,29,94]. Other trapping methods include CO 2 -baited traps (undescribed) [32,95], CO 2 -baited CDC traps without light [35], CDC traps without light baited with a Japanese quail or rabbit [9], CO 2 -baited CDC traps with sentinel birds (Japanese quail or chicken) or sentinel mammals (rabbit or guinea pig) [35], the EVS/ CO 2 Mosquito Trap [14], and a resting box baited with Red-footed falcon nestlings [96]. ...
Culex (Barraudius) modestus (Ficalbi 1889) are found in temperate regions across Europe, Asia, and Northern Africa. These mosquitoes thrive during the summer and prefer to breed in permanent vegetative habitats such as rice paddies and marshes. Culex modestus feed on a wide range of bird species but are highly attracted to humans, which makes them a potential ‘bridge’ vector for enzootic pathogens. There is compelling evidence that Culex modestus is an efficient vector for West Nile virus, potentially capable of causing epidemics in humans and other mammals. This species is also a likely vector for Usutu virus, avian malaria (Plasmodium spp.), and parasitic heartworms (Dirofilaria spp.). Culex modestus can be morphologically identified at the larval and adult stages, and a distinctive phenotype of this species is their ability to overwinter. Despite the widespread establishment of this mosquito species and their role as vectors for human pathogens, we lack sufficient knowledge on this species to implement and evaluate targeted vector control measures. Since Culex modestus can be considered a potential public health threat, there is a need for a better understanding of this mosquito species.
Graphical Abstract
... Horse owners around the capital have better access to veterinary care, information, and diagnostic techniques. Hajdú-Bihar County and the area of Hortobágy are well known for their migratory avian population, which carries a continuous risk of new virus introductions from Africa and where the bird population density also favors virus transmission [48,49]. Overwintering of mosquito species and temperature changes strongly correlate with virus enrichment in optimal areas [48]. ...
West Nile virus (WNV) is an emerging pathogen in Hungary, causing severe outbreaks in equines and humans since 2007. The aim of our study was to provide a comprehensive report on the clinical signs of West Nile neuroinvasive disease (WNND) in horses in Hungary. Clinical details of 124 confirmed equine WNND cases were collected between 2007 and 2019. Data about the seasonal and geographical presentation, demographic data, clinical signs, treatment protocols, and disease progression were evaluated. Starting from an initial case originating from the area of possible virus introduction by migratory birds, the whole country became endemic with WNV over the subsequent 12 years. The transmission season did not expand significantly during the data collection period, but vaccination protocols should be always reviewed according to the recent observations. There was not any considerable relationship between the occurrence of WNND and age, breed, or gender. Ataxia was by far the most common neurologic sign related to the disease, but weakness, behavioral changes, and muscle fasciculation appeared frequently. Apart from recumbency combined with inappetence, no other clinical sign or treatment regime correlated with survival. The survival rate showed a moderate increase throughout the years, possibly due to the increased awareness of practitioners.
... Common and lesser kestrels, peregrine falcons, hobbies, and merlins yielded bacteria Escherichia coli but also Staphylococcus spp., Mycobacterium spp., and Pseudomonas spp. as well as viruses (Vidal et al. 2017). Effects of virus infections in nestlings can be mitigated by maternal antibodies (Soltész et al. 2017). Nevertheless, hatching order negatively influences antibody levels in broods with seropositive nestlings (Soltész et al. 2017). ...
... Effects of virus infections in nestlings can be mitigated by maternal antibodies (Soltész et al. 2017). Nevertheless, hatching order negatively influences antibody levels in broods with seropositive nestlings (Soltész et al. 2017). Although malaria infections in male and female parents had no effect on clutch size, hatching success, or nesting success, parental effort by males may be limited by this parasite due to their higher investment during the chick rearing period (Ortego et al. 2008a). ...
The precise timing of reproduction is an important determinant of fitness of falcon. Increasing day length stimulates several neuroendocrine and endocrine secretions and triggers gonadal development in the anticipation of the breeding season. The female falcon starts egg formation after the achievement of body reserves that loss later during the early nesting period. The advance of laying time of falcons depends on the food supply in winter and spring, the amount of precipitation at that time of the year, and the spring temperatures. A breeding population consists of (1) breeding individuals of previous years, (2) first year individuals from the same area and (3) floaters. Floaters have a fundamental role on population growth, especially in small size populations. The decision of where to breed exerts a strong impact on fitness. Nevertheless, where nest sites are largely available without a concomitant food increase during the mating period, the number of breeding pairs does not increase. Overall, the cost of reproduction reduces subsequent survival and reproduction of parents that raise large number of offspring. Falcons changed eyries after successfully raising large broods, and eyrie switching increased the breeding success of females but not of males. An adaptive decline in average fertility, clutch size, and hatchability with progressive date of laying is characteristic of most bird species with a single clutch of variable size per year such as falcons. Successful individuals vary greatly in productivity, which is correlated with life span. Parental daily energy expenditure is positively associated with the increasing number of young in the brood. Male parents responded to brood size variation and adjusted their provisioning behaviour accordingly. Females show a conservative strategy aimed at maintaining and rationalizing fat reserves collected during the pre-reproductive phase. The post-fledging dependence period is the crucial stage when juveniles are still dependent from parents and move around the nest site with the family which occurs from the fledging day to the first of leaving the natal area. Reproductive performance of both sexes improved with age. In females this is due to a strong selective pressure upon non-competitive breeders, whereas males improve within individuals early in their life along with hunting skill.
... Common and lesser kestrels, peregrine falcons, hobbies, and merlins yielded bacteria Escherichia coli but also Staphylococcus spp., Mycobacterium spp., and Pseudomonas spp. as well as viruses (Vidal et al. 2017). Effects of virus infections in nestlings can be mitigated by maternal antibodies (Soltész et al. 2017). Nevertheless, hatching order negatively influences antibody levels in broods with seropositive nestlings (Soltész et al. 2017). ...
... Effects of virus infections in nestlings can be mitigated by maternal antibodies (Soltész et al. 2017). Nevertheless, hatching order negatively influences antibody levels in broods with seropositive nestlings (Soltész et al. 2017). Although malaria infections in male and female parents had no effect on clutch size, hatching success, or nesting success, parental effort by males may be limited by this parasite due to their higher investment during the chick rearing period (Ortego et al. 2008a). ...
Falcons show fine anatomical and physiological adaptations to capture different kinds of prey, but the mean prey mass correlated positively with mean mass of the falcon. The proportion of birds affect the diet breadth at species level, and the proportion of invertebrates negatively correlate with the rate of mammals. Thus, mammalian-eating falcons able to switch to alternative prey, and bird-eating falcons are forced to enlarge their foraging area to find enough avian prey. Ultimately, prey size and the type of prey increase the reversed size dimorphism (RSD) of falcons from insects to mammals to birds as prey. Falcons show a certain dietary plasticity due to environmental conditions that limit the distribution of prey and their abundances. The food composition can differ significantly depending on the season and falcons adjusted hunting efforts and techniques accordingly. In addition, the breadth of the food niche was positively correlated with habitat heterogeneity that ultimately increases the number of prey species, especially birds. Hunting techniques adopted by falcons depend on prey size and prey type, and their availability is mainly related to variable environmental factors. Anyway, they prioritize saving energy when foraging than time spent during foraging bouts. Avian predators are one of the major factors modifying avian and mammalian prey assemblages of a territory. Spatial synchrony in rodent population fluctuation is well described at boreal ecosystem and also in Central Europe but at a large spatial scale. Falcons that exclusively exploit migrating small birds for rearing young need to move to their breeding areas every year and then leave these areas outside the breeding season due to the absence of alternative prey out the seasonal migration periods. Flocking, vigilance, and mobbing are adopted by prey against falcons’ attacks, but hunting success of falcons is highest in attacks on small flocks. Populations of specialist predators often fluctuate with populations of preferred prey species. For example, stable, regular, synchronous, 10–12-year quasi-cycles have been demonstrated in grouses and gyrfalcons.
... However, subsequent studies in the House sparrow suggest that maternally-derived antibodies decline rapidly, being undetectable after 9 days, and do not confer protection to the juvenile after this point [43]. Maternal antibodies were suggested as a potential reason for the absence of disease in Redfooted falcon (Falco vespertinus) nestlings in the presence of infected mosquito vectors [44]. Avian immunity research has focused on humoral immunity, i.e., the induction of antibodies. ...
Reported human cases of West Nile virus (WNV) in Europe increased dramatically in 2018. Lineage 1 strains had been circulating in Euro-Mediterranean countries since the early 1990s. The subsequent introduction of WNV lineage 2 has been responsible for the remarkable upsurge of European WNV outbreaks since 2004, including the dramatic increase in human cases observed since 2018. The virus exists in a natural cycle between mosquitoes and wild birds, with humans and horses acting as dead-end hosts. As the key vertebrate hosts in the transmission cycle of WNV, avian species have been the focus of surveillance across many countries. Raptors appear particularly susceptible to WNV infection, resulting in higher prevalence, and in some cases exhibiting neurological signs that lead to the death of the animal. In addition, birds of prey are known to play an important role as WNV reservoir and potentially amplifying hosts of infection. Importantly, raptor higher susceptibility/prevalence may indicate infection through predation of infected prey. Consequently, they are considered important target species when designing cost-effective surveillance for monitoring both seasonal WNV circulation in endemic countries and its emergence into new areas, where migrating raptors may play a critical role in virus introduction. This review summarizes the different aspects of the current knowledge of WNV infection in birds of prey and evaluates their role in the evolution of the epizootic that is spreading throughout Europe.
... Although many mosquito species can transmit the virus, Culex species remains the major vector (Noden, Coburn, Wright, & Bradley, 2015;Shahhosseini et al., 2017;Soltesz et al., 2017). ...
West Nile virus (WNV) is an important emerging zoonotic arbovirus giving rise to clinical syndromes of varying severity in humans and horses. Culex mosquitoes are the main vector. Although WNV has been reported in many countries in the Middle East and Asia, little is known about its prevalence in equine populations in the Arabian Peninsula. We have carried out a serological study on 200 horses to assess WNV infection in the Eastern and Central regions of Saudi Arabia in 2013–2015. Sera were tested for the presence of WNV antibodies in parallel using a commercial enzyme‐linked immunosorbent assay (ELISA) kit and microneutralization (MN) tests. In comparison with the MN assay used as “gold standard,” we find the ELISA had a sensitivity of 94.7% and specificity of 80.1%. The prevalence of WNV neutralizing antibody ranged from 5 (17.3%) of 29 sera collected in Riyadh up to 15 (55.6%) of 27 sera collected from Al‐Qateef. These findings highlight the need to be aware of the possibility of WNV disease in humans and horses presenting with central nervous system disease in the Kingdom of Saudi Arabia.
Chapter 3 of this book is about the emergence, classisfication, types, diagnosis and pathology of multiple Avian Leukosis Viruses
Rift Valley Fever (RVF) and West Nile virus (WNV) are two important emerging Arboviruses transmitted by Aedes and Culex mosquitoes, typically Ae. caspius, Ae. detritus and Cx. pipiens in temperate regions. In Morocco, several outbreaks of WNV (1996, 2003, and 2010), affecting horses mostly, have been reported in northwestern regions resulting in the death of 55 horses and one‐person cumulatively. Serological evidence of WNV local circulation, performed one year after the latest outbreak, revealed WNV neutralizing bodies in 59 out of 499 tested participants (Hicham El Rhaffouli et al., 2012). The country also shares common borders with northern Mauritania, where RVF is often documented. Human movement, livestock trade, climate changes, and the availability of susceptible mosquito vectors are expected to increase the spread of these diseases in the country. Thus, in this study, we gathered a dataset summarizing occurrences of Ae. caspius, Ae. detritus and Cx. pipiens in the country, and generated model prediction for their potential distribution under both current and future (2050) climate conditions, as a proxy to identify regions at‐risk of RVF and WNV probable expansion. We found that the northwestern regions (where the population is most concentrated), specifically along the Atlantic coastline, are highly suitable for Ae. caspius, Ae. detritus and Cx. pipiens, under present‐day conditions. Future model scenarios anticipated possible range changes for the three mosquitoes under all climatic assumptions. All of the studied species are prospected to gain new areas that are currently not suitable, even under the most optimist scenario, thus placing additional human populations at risk.
Our maps and predictions offer an opportunity to strategically target surveillance and control programmes. Public health officials, entomological surveillance, and control delegation must augment efforts and continuously monitor these areas to reduce and minimize human infection risk.
