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Author  |
Vollmerhaus, B.; Roos, H.; Gerhards, H.; Knospe, C. |
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Title |
[Phylogeny, form and function of canine teeth in the horse] |
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Journal Article |
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Year |
2003 |
Publication |
Anatomia, histologia, embryologia |
Abbreviated Journal |
Anat Histol Embryol |
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Volume |
32 |
Issue |
4 |
Pages |
212-217 |
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Animals; Cuspid/*anatomy & histology/radiography; Evolution; Horses/*anatomy & histology; Male; Phylogeny; *Social Dominance |
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The canine teeth of the horse developed phylogenically from the simple, pointed, short-rooted tooth form of the leaf eating, in pairs living, Eocene horse Hyracotherium and served up to the Oligocene as a means of defense (self preservation). In the Miocene the living conditions of the Merychippus changed and they took to eating grass and adopted as a new behavior the life in a herd. The canine teeth possibly played an important role in fights for social ranking; they changed from a crown form to knife-like shape. In the Pliohippus the canine tooth usually remained in male horses and since the Pliocene, it contributed to the fights between stallions, to ensure that the offspring only came from the strongest animals (preservation of the species). Form and construction of the canine tooth are described and discussed in detail under the above mentioned phylogenic and ethologic aspects. |
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Institut fur Tieranatomie und Chirurgische Tierklinik der Universitat Munchen, Veterinarstrasse 13, D 80539 Munchen, Deutschland. c-neumueller@anat.vetmed.uni-muenchen.de |
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German |
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[Zur Phylogenie, Form und Funktion der Dentes canini des Pferdes] |
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0340-2096 |
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PMID:12919071 |
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refbase @ user @ |
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672 |
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Author |
Visser, E.K.; van Reenen, C.G.; Schilder, M.B.H.; Barneveld, A.; Blokhuis, H.J. |
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Title |
Learning performances in young horses using two different learning tests |
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Journal Article |
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Year |
2003 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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Volume |
80 |
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Pages |
311-326 |
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Keywords |
Horse; Personality; Learning performance; Consistency; Emotionality |
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Abstract |
To achieve optimal performance in equine sports as well as in leisure not only the physical abilities of the horse should be considered, but also the horse's personality. Besides temperamental aspects, like emotionality, or the horse's reactivity towards humans in handling situations, the learning ability of the horse is another relevant personality trait. To study whether differences in learning performance are consistent over time and whether individual learning performance differs between learning tests or is affected by emotionality, 39 young horses (Dutch Warmblood) were tested repeatedly in two learning tests. An aversive stimulus (AS) was used in one learning test (the avoidance learning test) and a reward was used in the other learning test (the reward learning test). During both learning tests behaviour as well as heart rate were measured. Each test was executed four times, twice when horses were 1 year of age, and twice when they were 2 years of age. Half of the horses received additional physical training from 6 months onwards. In both tests horses could be classified as either performers, i.e. completing the daily session, or as non-performers, i.e. returning to the home environment without having completed the daily session. There were some indications that emotionality might have caused non-performing behaviour, but these indications are not convincing enough to exclude other causes. Furthermore, there seem to be no simple relationships between measures of heart rate, behavioural responses putatively related to emotionality and learning performance. Horses revealed consistent individual learning performances within years in both tests, and in the avoidance learning test also between years. There was no significant correlation between learning performances in the avoidance learning test and the learning performances in the reward learning test. It is concluded that individual learning abilities are consistent over a short time interval for an avoidance learning test and a reward learning test and over a longer time for the avoidance learning test. Furthermore, results indicate that some horses perform better when they have to learn to avoid an aversive stimulus while others perform better when they are rewarded after a correct response. It is suggested that these differences may be relevant to design optimal individual training programmes and methods. |
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2009 |
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Visser, E.K.; Van Reenen, C.G.; Rundgren, M.; Zetterqvist, M.; Morgan, K.; Blokhuis, H.J. |
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Title |
Responses of horses in behavioural tests correlate with temperament assessed by riders |
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Journal Article |
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Year |
2003 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
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35 |
Issue |
2 |
Pages |
176-183 |
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Keywords |
Adult; Animals; *Behavior, Animal/physiology; Data Interpretation, Statistical; Female; *Handling (Psychology); Heart Rate/*physiology; Horses/physiology/*psychology; Humans; Male; Personality; Temperament/*physiology |
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REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212<W<0.505, P < 0.001). CONCLUSIONS: Correlations between behavioural and heart rate variables in the behavioural tests revealed that horses with a high level of locomotion or much restlessness behaviour exhibited high mean heart rate and low heart rate variability. In particular, heart rate variables in the behavioural tests were found to correlate with riders' rating scores. Furthermore, the underlying components of the handling test, retrieved with a principal component analysis (PCA) correlated with riders' rating scores while the underlying components of the novel object test did not. POTENTIAL CLINICAL RELEVANCE: It is concluded that it is possible for a large panel of assessors to agree upon a horse's temperament and that objective measures from behavioural tests correlate significantly with temperamental traits assessed by a panel of assessors. |
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Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.163, NL-3508 TD Utrecht, The Netherlands |
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English |
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0425-1644 |
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PMID:12638795 |
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Call Number |
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Serial |
1906 |
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Visser, E.K.; Van Reenen, C.G.; Engel, B.; Schilder, M.B.H.; Barneveld, A.; Blokhuis, H.J. |
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Title |
The association between performance in show-jumping and personality traits earlier in life |
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Journal Article |
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Year |
2003 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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Volume |
82 |
Issue |
4 |
Pages |
279-295 |
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Keywords |
Personality; Performance; Horses; Prediction; Individual differences; Behavioural tests |
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For a horse to succeed in a show-jumping career, the individual has to possess both excellent physical abilities as well as a suitable personality to perform under challenging conditions. Forty-one Dutch Warmblood horses were used to develop personality tests and correlations between test variables and early training performances in jumping were studied. In behavioural tests, during the first 2 years of the horses' lives, personality aspects like emotionality, reactivity to human and learning abilities were quantified. At the age of 3, horses were broken and received early training in show-jumping. The inter-relationship between several performance variables measured during this early training phase were studied using principal component analysis (PCA). Variables measured in the different personality tests (novel-object test, handling test, avoidance-learning test and a reward-learning test) showed no correlations, suggesting that these tests all triggered different aspects of a horse's personality. This study indicates that it is possible to predict a substantial part of the show-jumping performance of an individual horse later in life by personality traits earlier in life. |
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refbase @ user @ |
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326 |
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Author |
Vieuille, C.; Berger, F.; Le Pape, G.; Bellanger, D. |
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Title |
Sow behaviour involved in the crushing of piglets in outdoor farrowing huts--a brief report |
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Journal Article |
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Year |
2003 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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80 |
Issue |
2 |
Pages |
109-115 |
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Pig-maternal behaviour; Crushing; Free-ranging; Welfare |
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This study focuses on maternal activities involved in the trapping of piglets by the sow's body in outdoor farrowing systems and examine the mother-piglet context leading either to the death of piglets or to their survival. The behaviour of six Large-WhitexLandrace sows and their litters was continuously video recorded at their first and second parity, during the 40 h following parturition. Crushing mainly occurred at evening and night, during the first 12 h of farrowing and involved changes between lying, sitting and standing positions, as well as between udder and side lying. No piglet died from savaging. Nevertheless, aggressive behaviours of sows were observed, particularly in their first maternal experience. The immediate context of trapping was related to the labour of the sow and to the feeding and resting of piglets. The immediate crushing context was related to active avoidance of restless piglets while lying down, as well as sitting and standing behaviours. These results are discussed in terms of differential reactions of the sow to suckling attempts of piglets. |
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Equine Behaviour @ team @ |
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2235 |
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Author |
van Duijn, M. A.J. |
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Title |
Software for Social Network Analysis |
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Manuscript |
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2003 |
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This chapter gives a state-of-the art overview of available (free and commercial)
software for social network analysis as of fall 2003. It reviews and compares
six programs, illustrating their functionality with example data. Data manipulation
options and available support are also discussed. Furthermore, seventeen
other, of which nine special-purpose, software packages and ve software routine
packages for general statistical software are reviewed brie
y. The chapter
concludes with some recommendations. |
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Heymans Institute/DPMG |
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University of Groningen |
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Equine Behaviour @ team @ |
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5205 |
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Author |
Van Doorn G.S.; Hengeveld G.M.; Weissing F.J. |
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Title |
The Evolution of Social Dominance I: Two-player Models |
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Journal Article |
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2003 |
Publication |
Behavior |
Abbreviated Journal |
Behavior |
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140 |
Issue |
10 |
Pages |
1305-1332 |
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A difference in dominance rank is an often-used cue to resolve conflicts between two animals without escalated fights. At the group level, adherence to a dominance convention efficiently reduces the costs associated with conflicts, but from an individual's point of view, it is difficult to explain why a low ranking individual should accept its subordinate status. This is especially true if, as suggested by several authors, dominance not necessarily reflects differences in fighting ability but rather results from arbitrary historical asymmetries. According to this idea, rank differentiation emerges from behavioural strategies, referred to as winner and loser effects, in which winners of previous conflicts are more likely to win the current conflict, whereas the losers of previous conflicts are less likely to do so. In order to investigate whether dominance, based on such winner and loser effects, can be evolutionarily stable, we analyse a game theoretical model. The model focuses on an extreme case in which there are no differences in fighting ability between individuals at all. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. By means of numerical analysis, we find alternative evolutionarily stable strategies, which all utilize these asymmetries for conventional conflict resolution. One class of these strategies is based on winner and loser effects, thus generating evolutionarily stable dominance relations even in the absence of differences in resource holding potential. |
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Equine Behaviour @ team @ |
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5105 |
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Van Doorn G.S.; Hengeveld G.M.; Weissing F.J. |
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The Evolution of Social Dominance II: Multi-Player Models |
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2003 |
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Behavior |
Abbreviated Journal |
Behavior |
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140 |
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10 |
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1333-1358 |
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The social hierarchies observed in natural systems often show a high degree of transitivity. Transitive hierarchies do not only require rank differentiation within pairs of individuals but also a higher level ordering of relations within the group. Several authors have suggested that the formation of linear hierarchies at the group level is an emergent property of individual behavioural rules, referred to as winner and loser effects. Winner and loser effects occur if winners of previous conflicts are more likely to escalate the current conflict, whereas the losers of previous conflicts are less likely to do so. According to this idea, an individual's position in a hierarchy may not necessarily reflect its fighting ability, but may rather result from arbitrary historical asymmetries, in particular the history of victories and defeats. However, if this is the case, it is difficult to explain from an evolutionary perspective why a low ranking individual should accept its subordinate status. Here we present a game theoretical model to investigate whether winner and loser effects giving rise to transitive hierarchies can evolve and under which conditions they are evolutionarily stable. The main version of the model focuses on an extreme case in which there are no intrinsic differences in fighting ability between individuals. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. We show that, at evolutionary equilibrium, these asymmetries can be utilized for conventional conflict resolution. Several evolutionarily stable strategies are based on winner and loser effects and these strategies give rise to transitive hierarchies. |
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Equine Behaviour @ team @ |
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5106 |
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van der Willigen, R.F.; Frost, B.J.; Wagner, H. |
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How owls structure visual information |
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2003 |
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Animal Cognition |
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Anim. Cogn. |
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6 |
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1 |
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39-55 |
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Animals; *Cognition; Depth Perception; Discrimination Learning; Female; Male; *Strigiformes; *Visual Perception |
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Recent studies on perceptual organization in humans claim that the ability to represent a visual scene as a set of coherent surfaces is of central importance for visual cognition. We examined whether this surface representation hypothesis generalizes to a non-mammalian species, the barn owl ( Tyto alba). Discrimination transfer combined with random-dot stimuli provided the appropriate means for a series of two behavioural experiments with the specific aims of (1) obtaining psychophysical measurements of figure-ground segmentation in the owl, and (2) determining the nature of the information involved. In experiment 1, two owls were trained to indicate the presence or absence of a central planar surface (figure) among a larger region of random dots (ground) based on differences in texture. Without additional training, the owls could make the same discrimination when figure and ground had reversed luminance, or were camouflaged by the use of uniformly textured random-dot stereograms. In the latter case, the figure stands out in depth from the ground when positional differences of the figure in two retinal images are combined (binocular disparity). In experiment 2, two new owls were trained to distinguish three-dimensional objects from holes using random-dot kinematograms. These birds could make the same discrimination when information on surface segmentation was unexpectedly switched from relative motion to half-occlusion. In the latter case, stereograms were used that provide the impression of stratified surfaces to humans by giving unpairable image features to the eyes. The ability to use image features such as texture, binocular disparity, relative motion, and half-occlusion interchangeably to determine figure-ground relationships suggests that in owls, as in humans, the structuring of the visual scene critically depends on how indirect image information (depth order, occlusion contours) is allocated between different surfaces. |
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Institut fur Biologie II, RWTH Aachen, Kopernikusstrasse 16, 52074, Aachen, Germany. willigen@bio2.rwth-aachen.de |
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1435-9448 |
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PMID:12658534 |
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Equine Behaviour @ team @ |
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2582 |
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Author |
Valero, N. |
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Title |
West Nile virus: a new challenge? |
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2003 |
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Investigacion Clinica |
Abbreviated Journal |
Invest Clin |
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44 |
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3 |
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175-177 |
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Animal Migration; Animals; Bird Diseases/virology; Birds; Caribbean Region; Central America; Culex/virology; Horse Diseases/virology; Horses; Humans; Insect Vectors/virology; North America/epidemiology; South America; West Nile Fever/*epidemiology/transmission/veterinary; West Nile virus/*physiology |
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West Nile Virus (WNV), a member of the family Flaviviridae, was first isolated in 1937. Since the original isolation of the WNV outbreaks have occurred with increase in frequency of cases in humans and horses, apparent increase in severe human disease and high avian death rates. In 1999, 2000 and 2002 outbreaks of the WNV encephalitis were reported in horses, birds and humans from New York and Canada. Ornithophilic mosquitoes are the principal vectors of the WNV and birds of several species chiefly migrants appear to be the major introductory or amplifying host. The pattern of outbreaks in the old and new world suggests that viremic migratory birds may also contribute to movement of the virus. If so, Central America, Caribbean Islands and countries of South America including Venezuela, are in potential risk for suffering a severe outbreak for WNV, since several species of birds have populations that pass trough New York and cross the western north Atlantic or Caribbean Sea. It is important the knowledge of the ecology of WNV as well of the efficacy of control efforts in order to minimize the public health impact in these countries, where all population is susceptible to this infection. |
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Spanish |
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Virus del Nilo Occidental: Un nuevo reto? |
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0535-5133 |
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PMID:14552056 |
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Equine Behaviour @ team @ |
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2640 |
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