Evaluation of the spatial and temporal distribution of and risk factors for Bluetongue serotype 1 epidemics in sheep Extremadura (Spain), 2007–2011

Pascual-Linaza, Ana V.; Martínez‐López, Beatriz; Pfeiffer, Dirk U.; Moreno, José Carlos; Sanz, Cristina; Sánchez-Vizcaíno, José Manuel

doi:10.1016/j.prevetmed.2014.05.009

Cited by 15 publications

(19 citation statements)

References 25 publications

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“…For animal density, cattle are considered BTV amplifiers because of their long-term viraemia [1] and the major role they have in BTV diffusion is confirmed in the present study and in the findings obtained from other studies [39, 40, 41]. The small ruminants’ density was identified as a protective factor.…”

Section: Discussionsupporting

confidence: 87%

“…The small ruminants’ density was identified as a protective factor. In the present study, it was negatively associated with BTV infection, while in the cited studies it resulted as a risk factor [39, 40, 41]. Nevertheless, no association could be proven in the study conducted by Arenas-Montes et al [42], while Pioz et al [43] confirmed a negative association.…”

Section: Discussioncontrasting

confidence: 56%

“…Relative to the sheep herd size affecting the likelihood of being BTV seropositive, there is limited amount of information in the literature. The herd size was positively associated with BTV1 epidemic in Spain [40], while in comparable studies only sheep density in the proximity of the farm was considered. In the present study, BTV infection decreased significantly with the increase of the number of sheep inside a farm.…”

Section: Discussionmentioning

confidence: 99%

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A cross-sectional serosurvey in a sheep population in central Italy following a bluetongue epidemic

et al. 2019

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Bluetongue (BT) is a viral disease that affects ruminants and is transmitted by midges of the genus Culicoides spp. The seroprevalence, the clinical form and the occurrence rates significantly differ in relation to several factors such as bluetongue virus (BTV) serotype, host species, breed susceptibility, specific previous exposure, vector ecology, husbandry and health status. Following the 2001–2006 BTV2 and BTV16 epidemics in central Italy, a new epidemic caused by BTV1 occurred in 2013–2015 causing 398 outbreaks in a susceptible population of about 1 million ruminants. The present study assessed the BTV1 seroprevalence in the sheep population of central Italy by conducting two cross-sectional surveys, in the proximity of and within BT outbreak farms. A total of 2,984 sheep from 437 farms were sampled. The animal-level prevalence was 19% (95% CI: 17–21%), the between-herd prevalence was 46% (95% CI: 41–51%) and the within-herd prevalence was 21% (95% CI: 16–26%). Risk factors were investigated by logistic regression models. Living on a farm where an outbreak occurred and the number of outbreaks in proximity of the farm were identified as risk factors, while herd size was identified as a protective factor. This study represents the first BT survey in southern Europe and reports valuable findings on BTV epidemiology. Despite intensive virus circulation, the estimated seroprevalences were low. The assessment of the population immunity level is crucial for defining an efficient vaccination strategy and for predicting the impact of future virus circulation. In view of the low seroprevalence detected albeit an extensive BTV1 circulation, the population immunity was likely to be inadequate in preventing new BTV1 epidemics. Moreover, considering the recurrent introduction of new serotypes from North Africa and the Balkans, the control of multi-serotype BTV infections will continue to present a challenge in the near future.

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Section: Discussionsupporting

confidence: 87%

Section: Discussioncontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

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A cross-sectional serosurvey in a sheep population in central Italy following a bluetongue epidemic

et al. 2019

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“…Local conditions such as humidity, temperature, wind and land cover could have been considered as they are known to impact Culicoïdes presence, persistence, activity and dissemination (Purse et al., ; Sanders et al., ; Wilson & Mellor, ; Wittmann, Mellor, & Baylis, ). Indicators of hosts presence and abundance such as local density of cows and small ruminants or probability of interaction with red deer have been reported as risk factors for the persistence in hosts and local transmission (Allepuz et al., ; Durand et al., ; Pascual‐Linaza et al., ). Yet, these variables had been identified as risk factors during the occurrence of outbreaks in a limited period of time, whereas the animals sampled in our study could have seroconverted over a wide temporal window during which many of them had lived in different environments.…”

Section: Methodsmentioning

confidence: 99%

Serological status for BTV-8 in French cattle prior to the 2015 re-emergence

Courtejoie

Durand

Bréard

et al. 2017

Transbound Emerg Dis

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The animal-level seroprevalence averaged at 44%, with a strong age pattern reflecting the cumulative exposure to both natural infection and to vaccination. A multivariable analysis allowed separating the respective effects of both exposures. A higher proportion of seropositivity risk was attributed to vaccination (67.4%) than to exposure to natural infection (24.2%). The evolution of seroprevalence induced by the two main risk factors in 74 mainland departments was reconstructed between the vaccination ban (2013) and the re-emergence (2015). We showed a striking decrease in seroprevalence with time after the vaccination ban, due to population renewal, which could have facilitated virus transmission leading to the current outbreak situation. K E Y W O R D Sbluetongue, BTV-8, cattle, France, prevalence, re-emergence, serology

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“…The Autonomous Community of Extremadura has been one of the regions in Spain most severely affected by bluetongue epidemics (Pascual-Linaza et al, 2014). Framed within a national surveillance program for BTV in Extremadura, CDC miniature light traps (Model 512; John W. Hock Company, Gainesville, Florida, USA) were used to capture adult Culicoides during 2014 in previously selected farms.…”

Section: Methodsmentioning

confidence: 99%

Primera cita de <em>Culicoides paradoxalis</em> Ramilo & Delécolle, 2013 (Diptera, Ceratopogonidae) en España

et al. 2015

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The ceratopogonid Culicoides paradoxalis Ramilo & Delécolle, 2013 is recorded for the first time in Spain based on reliable morphological evidence according to the previous descriptions of other authors. A total of 438 females (349 nulliparous and 89 parous) and a single male were collected with CDC miniature light traps at three different livestock-associated locations in Extremadura Autonomous Community (Spain) in 2014. Most specimens were captured between June and August, suggesting a univoltine pattern for this species extended over summer and early autumn. Although the number of collections of C. paradoxalis is low in comparison with the dominant species, the occurrence of this species in monitoring surveillance programs should deserve specific attention in order to estimate the accurate ratio of potential vectors unmistakably. Interesting information about the period of flight and illustrated morphological features are presented for C. paradoxalis in the current paper.

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Evaluation of the spatial and temporal distribution of and risk factors for Bluetongue serotype 1 epidemics in sheep Extremadura (Spain), 2007–2011

Cited by 15 publications

References 25 publications

A cross-sectional serosurvey in a sheep population in central Italy following a bluetongue epidemic

A cross-sectional serosurvey in a sheep population in central Italy following a bluetongue epidemic

Serological status for BTV-8 in French cattle prior to the 2015 re-emergence

Primera cita de <em>Culicoides paradoxalis</em> Ramilo & Delécolle, 2013 (Diptera, Ceratopogonidae) en España

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