99 research outputs found

    Understanding spatio-temporal variability in the reproduction ratio of the bluetongue (BTV-1) epidemic in southern Spain (Andalusia) in 2007 using epidemic trees

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    Andalusia (Southern Spain) is considered one of the main routes of introduction of bluetongue virus (BTV) into Europe, evidenced by a devastating epidemic caused by BTV-1 in 2007. Understanding the pattern and the drivers of BTV-1 spread in Andalusia is critical for effective detection and control of future epidemics. A long-standing metric for quantifying the behaviour of infectious diseases is the case-reproduction ratio (Rt), defined as the average number of secondary cases arising from a single infected case at time t (for t>0). Here we apply a method using epidemic trees to estimate the between-herd case reproduction ratio directly from epidemic data allowing the spatial and temporal variability in transmission to be described. We then relate this variability to predictors describing the hosts, vectors and the environment to better understand why the epidemic spread more quickly in some regions or periods. The Rt value for the BTV-1 epidemic in Andalusia peaked in July at 4.6, at the start of the epidemic, then decreased to 2.2 by August, dropped below 1 by September (0.8), and by October it had decreased to 0.02. BTV spread was the consequence of both local transmission within established disease foci and BTV expansion to distant new areas (i.e. new foci), which resulted in a high variability in BTV transmission, not only among different areas, but particularly through time, which suggests that general control measures applied at broad spatial scales are unlikely to be effective. This high variability through time was probably due to the impact of temperature on BTV transmission, as evidenced by a reduction in the value of Rt by 0.0041 for every unit increase (day) in the extrinsic incubation period (EIP), which is itself directly dependent on temperature. Moreover, within the range of values at which BTV-1 transmission occurred in Andalusia (20.6°C to 29.5°C) there was a positive correlation between temperature and Rt values, although the relationship was not linear, probably as a result of the complex relationship between temperature and the different parameters affecting BTV transmission. Rt values for BTV-1 in Andalusia fell below the threshold of 1 when temperatures dropped below 21°C, a much higher threshold than that reported in other BTV outbreaks, such as the BTV-8 epidemic in Northern Europe. This divergence may be explained by differences in the adaptation to temperature of the main vectors of the BTV-1 epidemic in Andalusia (Culicoides imicola) compared those of the BTV-8 epidemic in Northern Europe (Culicoides obsoletus). Importantly, we found that BTV transmission (Rt value) increased significantly in areas with higher densities of sheep. Our analysis also established that control of BTV-1 in Andalusia was complicated by the simultaneous establishment of several distant foci at the start of the epidemic, which may have been caused by several independent introductions of infected vectors from the North of Africa. We discuss the implications of these findings for BTV surveillance and control in this region of Europe

    Epidemiology and spatio‐temporal analysis of West Nile virus in horses in Spain between 2010 and 2016

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    During the last decade, West Nile virus (WNV) outbreaks have increased sharply in both horses and human in Europe. The aims of this study were to evaluate characteristics and spatio‐temporal distribution of WNV outbreaks in horses in Spain between 2010 and 2016 in order to identify the environmental variables most associated with WNV occurrence and to generate high‐resolution WNV suitability maps to inform risk‐based surveillance strategies in this country. Between August 2010 and November 2016, a total of 403 WNV suspected cases were investigated, of which, 177 (43.9%) were laboratory confirmed. Mean values of morbidity, mortality and case fatality rates were 7.5%, 1.6% and 21.2%, respectively. The most common clinical symptoms were as follows: tiredness/apathy, recumbency, muscular tremor, ataxia, incoordination and hyperaesthesia. The outbreaks confirmed during the last 7 years, with detection of WNV RNA lineage 1 in 2010, 2012, 2013, 2015 and 2016, suggest an endemic circulation of the virus in Spain. The spatio‐temporal distribution of WNV outbreaks in Spain was not homogeneous, as most of them (92.7%) were concentrated in western part of Andalusia (southern Spain) and significant clusters were detected in this region in two non‐consecutive years. These findings were supported by the results of the space–time scan statistics permutation model. A presence‐only MaxEnt ecological niche model was used to generate a suitability map for WNV occurrence in Andalusia. The most important predictors selected by the Ecological Niche Modeling were as follows: mean annual temperature (49.5% contribution), presence of Culex pipiens (19.5% contribution), mean annual precipitation (16.1% contribution) and distance to Ramsar wetlands (14.9% contribution). Our results constitute an important step for understanding WNV emergence and spread in Spain and will provide valuable information for the development of more cost‐effective surveillance and control programmes and improve the protection of horse and human populations in WNV‐endemic areas.info:eu-repo/semantics/acceptedVersio

    Quantitative assessment of the probability of bluetongue virus overwintering by horizontal transmission : application to Germany

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    Even though bluetongue virus (BTV) transmission is apparently interrupted during winter, bluetongue outbreaks often reappear in the next season (overwintering). Several mechanisms for BTV overwintering have been proposed, but to date, their relative importance remain unclear. In order to assess the probability of BTV overwintering by persistence in adult vectors, ruminants (through prolonged viraemia) or a combination of both, a quantitative risk assessment model was developed. Furthermore, the model allowed the role played by the residual number of vectors present during winter to be examined, and the effect of a proportion of Culicoides living inside buildings (endophilic behaviour) to be explored. The model was then applied to a real scenario: overwintering in Germany between 2006 and 2007. The results showed that the limited number of vectors active during winter seemed to allow the transmission of BTV during this period, and that while transmission was favoured by the endophilic behaviour of some Culicoides, its effect was limited. Even though transmission was possible, the likelihood of BTV overwintering by the mechanisms studied seemed too low to explain the observed re-emergence of the disease. Therefore, other overwintering mechanisms not considered in the model are likely to have played a significant role in BTV overwintering in Germany between 2006 and 2007

    Saliva secretory IgA kinetics in obese subjects submitted to a graded exercise test

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    INTRODUCTION: Secretory IgA (sIgA) is predominant immunoglobulin in secretions of the mucosal immune system. It inhibit attachment and replication of pathogenic microorganism, preventing colonization by these pathogens. Therefore, sIgA is consider the first line of defense against pathogens. Previous studies have indicated a direct link between low salivary sIgA levels with of upper respiratory tract infections (UTRI) episodes in endurance sports and elite athletes. PURPOSE: Determine the effect of a maximal graded exercise test on the saliva sIgA levels in obese adult subjects. METHODS: Eleven obese male subjects (Age 31± 1.53 years) were recruited. The Body Mass Index (BMI) and, Waist Circumference (WC) were measured. Graded exercise test was performed on an electrically-braked cycle ergometer (Lode). The Heart rate (HR) was registered using a digital pulse meter (Polar FT1 model) before, immediately finished the exercise and after 30 min post- exercise test. The saliva samples were collected alongside with HR during the test. RESULTS: The WC (110.37 ± 3.89 cm) and BMI (34.73 ± 1.62 kg/m2) values confirmed the obesity state in the participants. The HR at basal was 77.09 ± 3.10 bpm, at post exercise, the HR mean was 175.45 ± 4.94 bpm (p \u3c0.0001 vs basal). Finally, at 30 post exe, the HR was 91.81 ± 3.01 bpm (P \u3c0.0001 vs post-exe). In basal state, the sIgA concentration was 94.21 ± 13.57 ”m/mL. At post exe, the sIgA mean was 175.9 ± 22.45 ”m/mL (p\u3c0.05 vs basal). Finally, 30’ post-exercise the sIgA level was 91.39 ± 10.40 ”m/mL. However, the sIgA was not modified by the exercise. CONCLUSION: The present work demonstrates that the salivary sIgA increases temporally as a response to the graded exercise test in obese adults. Although, the changes in the sIgA concentration was not accompanied with a major sIgA secretion in the saliva

    Seropositivity and Risk Factors Associated with Toxoplasma gondii Infection in Wild Birds from Spain

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    Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n = 610), Strigiformes (n = 260), Ciconiiformes (n = 156), Gruiformes (n = 21), and other orders (n = 32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≄1∶25) were found in 282 (26.1%, IC95%:23.5–28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) “vulnerable” Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN “near threatened” red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour

    Cardiorespiratory, metabolic and muscular responses during a video-recorded aerobic dance session on an air dissipation platform

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    Background: Aerobic dance (AD) is an appropriate physical activity for improving cardiorespiratory fitness. This study aimed to compare cardiorespiratory and metabolic responses, and muscle fatigue between an air dissipation platform (ADP) and a hard surface during a video-recorded AD session. Methods: 25 healthy young women (23.3 ± 2.5 years) completed three sessions. In session 1, participants performed an incremental test to exhaustion on a treadmill. One week after session 1, participants were randomly assigned in a crossover design to perform video-recorded AD sessions on an ADP and on a hard surface (sessions 2 and 3). Cardiorespiratory and metabolic responses were assessed during AD sessions. Muscular fatigue was measured before and after AD sessions by a countermovement jump test. Results: Significantly higher heart rate, respiratory exchange ratio, pulmonary ventilation, ventilatory oxygen equivalent, and ventilatory carbon dioxide equivalent were observed on an ADP than on a hard surface (p 0.05). Conclusions: Video-recorded AD on an ADP increased the cardioventilatory and metabolic responses compared to a hard surface, preventing further muscle fatigue

    Aerobic Dance on an Air Dissipation Platform Improves Cardiorespiratory, Muscular and Cellular Fitness in the Overweight and Obese Elderly

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    Background: Obesity is a global health problem associated with a high number of comorbidities that decrease functional capacity, especially in elderly people. Aerobic dance is considered a viable strategy to prevent the effects of aging, mainly in obese and overweight elderly people. This study aimed to evaluate the effects of aerobic dance on an air dissipation platform (ADP) on body composition, oxidative stress and muscular and cardiorespiratory fitness in elderly people. Methods: In total, 32 elderly adults (67.1 ± 3.6) were divided into 3 groups based on body mass index: healthy (HG), overweight (OWG) and obese (OG). Training program of aerobic dance on an ADP was carried out twice a week for 12 weeks. Results: OWG (p = 0.016) and OG decreased their weight (p < 0.001). There was a significant decrease in malondialdehyde concentrations in all experimental groups (p < 0.05). OWG and OG significantly improved their peak oxygen uptake (p < 0.01). HG increased the vertical jump height (p < 0.05), and HG and OG improved the power output of the lower extremities (p < 0.05). Conclusions: The aerobic dance on an ADP may be an effective alternative to lose weight, prevent oxidative stress and improve cardiorespiratory fitness in obese and overweight elderly people

    Assessing the variability in transmission of bovine tuberculosis within Spanish cattle herds

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    In Spain, despite years of efforts to eradicate bovine tuberculosis (bTB), the disease is still endemic, with some areas of high prevalence. In this context, the surveillance and control plans may need to be re-evaluated, and understanding the dynamics of bTB spread within Spanish herds may help to develop new strategies for reducing the time for detection of infected herds and for the elimination of bTB from the herds already infected. Here, we developed a compartmental stochastic model to simulate bTB within-herd transmission, fed it with epidemiological data from 22 herds (obtained from a previous work) and carried out parameter inference using Approximate Bayesian Computing methods We also estimated the “Within-herd transmission potential Number” (Rh), i.e. the average number of secondary cases generated by a single animal infected introduced into a totally susceptible herd, considering different scenarios depending on the frequency of controls. The median global values obtained for the transmission parameters were: for the transmission coefficient (ÎČ), 0.014 newly infected animals per infectious individual per day (i.e. 5.2 per year), for the rate at which infected individuals become infectious (α), 0.01 per day (equivalent to a latent period of 97 days), and for the rate at which infected individuals become reactive to the skin test (α1), 0.08 per day (equivalent to a period of 12 days for an infected animal to become reactive). However, the results also evidenced a great variability in the estimates of those parameters (in particular ÎČ and α) among the 22 herds. Considering a 6-month interval between tests, the mean Rh was 0.23, increasing to 0.82 with an interval of 1 year, and to 2.01 and 3.47 with testing intervals of 2 and 4 years, respectively.info:eu-repo/semantics/publishedVersio

    Toxoplasma gondii in sympatric domestic and wild ungulates in the Mediterranean ecosystem

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    Toxoplasma gondii is a zoonotic protozoan of worldwide distribution. The present study provides information on risk factors affecting T. gondii infection in domestic and free-ranging wild ungulates sharing habitats in Mediterranean ecosystems in Spain. Serum samples from 482 extensively reared domestic ruminants and 2351 wild ungulates were tested for T. gondii antibodies using the modified agglutination test (MAT, cut-off 1:25). Toxoplasma gondii seroprevalence was 41.2% of 194 sheep, 18.6% of 199 cattle and 5.6% of 89 goats. The main risk factors associated with infection in livestock were the presence of cats, feeding on the ground and at stubble fields. In wild ungulates, T. gondii antibodies were detected in 10.5% of 1063 red deer, 15.6% of 294 fallow deer, 5.6% of 216 European mouflon, 5.6% of 90 Spanish ibex, 13.6% of 22 roe deer and 18.6% of 666 wild boars. The risk factors affecting T. gondii infection in wildlife were species, age and hunting season. Significantly higher seroprevalence was found in domestic ruminants, particularly in sheep, compared to the wild species tested. The present study indicates widespread exposure to T. gondii among domestic and wild ungulates in Southern Spain, with significant differences among species sharing the same ecosystem. The high seroprevalence observed in domestic ruminants, particularly in sheep, reinforces the need for farm management practices to control the risk factors associated with T. gondii infection in extensively reared livestock. Consumption of raw and undercooked food products from domestic and wildlife species may have important implications for public health.info:eu-repo/semantics/acceptedVersio

    Toxoplasma gondii in sympatric domestic and wild ungulates in the Mediterranean ecosystem

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    Toxoplasma gondii is a zoonotic protozoan of worldwide distribution. The present study provides information on risk factors affecting T. gondii infection in domestic and free-ranging wild ungulates sharing habitats in Mediterranean ecosystems in Spain. Serum samples from 482 extensively reared domestic ruminants and 2351 wild ungulates were tested for T. gondii antibodies using the modified agglutination test (MAT, cut-off 1:25). Toxoplasma gondii seroprevalence was 41.2% of 194 sheep, 18.6% of 199 cattle and 5.6% of 89 goats. The main risk factors associated with infection in livestock were the presence of cats, feeding on the ground and at stubble fields. In wild ungulates, T. gondii antibodies were detected in 10.5% of 1063 red deer, 15.6% of 294 fallow deer, 5.6% of 216 European mouflon, 5.6% of 90 Spanish ibex, 13.6% of 22 roe deer and 18.6% of 666 wild boars. The risk factors affecting T. gondii infection in wildlife were species, age and hunting season. Significantly higher seroprevalence was found in domestic ruminants, particularly in sheep, compared to the wild species tested. The present study indicates widespread exposure to T. gondii among domestic and wild ungulates in Southern Spain, with significant differences among species sharing the same ecosystem. The high seroprevalence observed in domestic ruminants, particularly in sheep, reinforces the need for farm management practices to control the risk factors associated with T. gondii infection in extensively reared livestock. Consumption of raw and undercooked food products from domestic and wildlife species may have important implications for public health.info:eu-repo/semantics/acceptedVersio
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