Seroepidemiological study of Q fever in domestic ruminants in semi-extensive grazing systems

<p>Abstract</p> <p>Background</p> <p>Q fever, a worldwide zoonotic disease caused by <it>Coxiella burnetii</it>, is endemic in northern Spain where it has been reported as responsible for large series of human pneumonia cases and domestic ruminants' reproductive disorders. To investigate pathogen exposure among domestic ruminants in semi-extensive grazing systems in northern Spain, a serosurvey was carried out in 1,379 sheep (42 flocks), 626 beef cattle (46 herds) and 115 goats (11 herds). Serum antibodies were analysed by ELISA and positive samples were retested by Complement Fixation test (CFT) to detect recent infections.</p> <p>Results</p> <p>ELISA anti-<it>C. burnetii </it>antibody prevalence was slightly higher in sheep (11.8 ± 2.0%) than in goats (8.7 ± 5.9%) and beef cattle (6.7 ± 2.0%). Herd prevalence was 74% for ovine, 45% for goat and 43% for bovine. Twenty-one percent of sheep flocks, 27% of goat and 14% of cattle herds had a <it>C. burnetii </it>seroprevalence ≥ 20%. Only 15 out of 214 ELISA-positive animals reacted positive by CFT. Age-associated seroprevalence differed between ruminant species with a general increasing pattern with age. No evidence of correlation between abortion history and seroprevalence rates was observed despite the known abortifacient nature of <it>C. burnetii </it>in domestic ruminants.</p> <p>Conclusions</p> <p>Results reported herein showed that sheep had the highest contact rate with <it>C. burnetii </it>in the region but also that cattle and goats should not be neglected as part of the domestic cycle of <it>C. burnetii</it>. This work reports basic epidemiologic patterns of <it>C. burnetii </it>in semi-extensive grazed domestic ruminants which, together with the relevant role of <it>C. burnetii </it>as a zoonotic and abortifacient agent, makes these results to concern both Public and Animal Health Authorities.</p

Host and environmental factors modulate the exposure of free-ranging and farmed red deer (Cervus elaphus) to coxiella burnetii

The control of multihost pathogens, such as Coxiella burnetii, should rely on accurate information about the roles played by the main hosts. We aimed to determine the involvement of the red deer (Cervus elaphus) in the ecology of C. burnetii. We predicted that red deer populations from broad geographic areas within a European context would be exposed to C. burnetii, and therefore, we hypothesized that a series of factors would modulate the exposure of red deer to C. burnetii. To test this hypothesis, we designed a retrospective survey of 47 Iberian red deer populations from which 1,751 serum samples and 489 spleen samples were collected. Sera were analyzed by enzyme-linked immunosorbent assays (ELISA) in order to estimate exposure to C. burnetii, and spleen samples were analyzed by PCR in order to estimate the prevalence of systemic infections. Thereafter, we gathered 23 variables— within environmental, host, and management factors—potentially modulating the risk of exposure of deer to C. burnetii, and we performed multivariate statistical analyses to identify the main risk factors. Twenty-three populations were seropositive (48.9%), and C. burnetii DNA in the spleen was detected in 50% of the populations analyzed. The statistical analyses reflect the complexity of C. burnetii ecology and suggest that although red deer may maintain the circulation of C. burnetii without third species, the most frequent scenario probably includes other wild and domestic host species. These findings, taken together with previous evidence of C. burnetii shedding by naturally infected red deer, point at this wild ungulate as a true reservoir for C. burnetii and an important node in the life cycle of C. burnetii, at least in the Iberian Peninsula

Screening a Peptide Library by DSC and SAXD: Comparison with the Biological Function of the Parent Proteins

We have recently identified the membranotropic regions of the hepatitis C virus proteins E1, E2, core and p7 proteins by observing the effect of protein-derived peptide libraries on model membrane integrity. We have studied in this work the ability of selected sequences of these proteins to modulate the Lβ-Lα and Lα-HII phospholipid phase transitions as well as check the viability of using both DSC and SAXD to screen a protein-derived peptide library. We demonstrate that it is feasible to screen a library of peptides corresponding to one or several proteins by both SAXD and DSC. This methodological combination should allow the identification of essential regions of membrane-interacting proteins which might be implicated in the molecular mechanism of membrane fusion and/or budding

Protection of Spanish Ibex (Capra pyrenaica) against Bluetongue Virus Serotypes 1 and 8 in a Subclinical Experimental Infection

Many wild ruminants such as Spanish ibex (Capra pyrenaica) are susceptible to Bluetongue virus (BTV) infection, which causes disease mainly in domestic sheep and cattle. Outbreaks involving either BTV serotypes 1 (BTV-1) and 8 (BTV-8) are currently challenging Europe. Inclusion of wildlife vaccination among BTV control measures should be considered in certain species. In the present study, four out of fifteen seronegative Spanish ibexes were immunized with a single dose of inactivated vaccine against BTV-1, four against BTV-8 and seven ibexes were non vaccinated controls. Seven ibexes (four vaccinated and three controls) were inoculated with each BTV serotype. Antibody and IFN-gamma responses were evaluated until 28 days after inoculation (dpi). The vaccinated ibexes showed significant (P<0.05) neutralizing antibody levels after vaccination compared to non vaccinated ibexes. The non vaccinated ibexes remained seronegative until challenge and showed neutralizing antibodies from 7 dpi. BTV RNA was detected in the blood of non vaccinated ibexes from 2 to the end of the study (28 dpi) and in target tissue samples obtained at necropsy (8 and 28 dpi). BTV-1 was successfully isolated on cell culture from blood and target tissues of non vaccinated ibexes. Clinical signs were unapparent and no gross lesions were found at necropsy. Our results show for the first time that Spanish ibex is susceptible and asymptomatic to BTV infection and also that a single dose of vaccine prevents viraemia against BTV-1 and BTV-8 replication

Staphylococcal phenotypes induced by naturally occurring and synthetic membrane-interactive polyphenolic β-lactam resistance modifiers.

Galloyl catechins, in particular (-)-epicatechin gallate (ECg), have the capacity to abrogate β-lactam resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA); they also prevent biofilm formation, reduce the secretion of a large proportion of the exoproteome and induce profound changes to cell morphology. Current evidence suggests that these reversible phenotypic traits result from their intercalation into the bacterial cytoplasmic membrane. We have endeavoured to potentiate the capacity of ECg to modify the MRSA phenotype by stepwise removal of hydroxyl groups from the B-ring pharmacophore and the A:C fused ring system of the naturally occurring molecule. ECg binds rapidly to the membrane, inducing up-regulation of genes responsible for protection against cell wall stress and maintenance of membrane integrity and function. Studies with artificial membranes modelled on the lipid composition of the staphylococcal bilayer indicated that ECg adopts a position deep within the lipid palisade, eliciting major alterations in the thermotropic behaviour of the bilayer. The non-galloylated homolog (-)-epicatechin enhanced ECg-mediated effects by facilitating entry of ECg molecules into the membrane. ECg analogs with unnatural B-ring hydroxylation patterns induced higher levels of gene expression and more profound changes to MRSA membrane fluidity than ECg but adopted a more superficial location within the bilayer. ECg possessed a high affinity for the positively charged staphylococcal membrane and induced changes to the biophysical properties of the bilayer that are likely to account for its capacity to disperse the cell wall biosynthetic machinery responsible for β-lactam resistance. The ability to enhance these properties by chemical modification of ECg raises the possibility that more potent analogs could be developed for clinical evaluation

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

Changes in the dynamics of Coxiella burnetii infection in dairy cattle: An approach to match field data with the epidemiological cycle of C. burnetii in endemic herds

This study aimed to evaluate changes in the epidemiological status of Coxiella burnetii in dairy cattle herds to better understand the epidemiology of the infection and to predict its evolution. Bulk-tank milk (BTM) and serum samples were collected from 94 dairy cattle herds and analyzed by ELISA (BTM and sera) and PCR (BTM) in study 1 (S1). Two years later (study 2; S2), the same farms were visited with a similar sampling approach. To estimate seroconversion during this period, blood samples were collected from the maximum possible number of animals surveyed in S1. Environmental samples were collected in S2 to identify active shedding. Farms were allocated into 3 different categories in each study according to PCR and ELISA results: category A, with BTM ELISA and PCR positive herds and at least 1 seropositive animal; category B, with BTM ELISA or PCR positive herds or individual sera positive; and category C, with all negative results among herds. Changes in herd category between S1 and S2 were grouped in 9 classes. Two statistical models, one to search for drives of within-herd changes in C. burnetii infection status and another to look for variables modulating individual changes in C. burnetii antibody level, were built. Several herds in category A in S1 remained in that category 2yr later, indicating that C. burnetii can remain within a herd for a long time. Most of the herds with seroconversion and detection of the bacterium in the environment belonged to category A, suggesting active and recent infections. Changes in the epidemiological status of herds were driven by local densities of domestic ruminants, showing the implication of neighbor reservoirs; whereas individual changes in antibody levels were modulated by variation in the epidemiological status of herds. Observed changes in epidemiological status allowed depiction of the hypothesized life cycle of C. burnetii within dairy cattle herds, which should be tested by future long-term series studies on C. burnetii infection to help fitting control measures (e.g., vaccination) to within-herd C. burnetii status.This study was supported by Instituto Nacional de Tecnología Agraria y Alimentaria (INIA, Madrid, Spain) RTA 2009-00017-00 and the European Regional Development Fund (Brussels, Belgium). A. Piñero is the recipient of a predoctoral fellowship from INIA. F. Ruiz-Fons is funded by the Spanish Ministry for Economy and Competitiveness (Madrid, Spain) through a ‘Juan de la Cierva’ contract.Peer Reviewe

Border disease virus seroprevalence correlates to antibodies in bulk-tank milk and reproductive performance of dairy sheep flocks

There is a great need to establish effective tools to control border disease virus (BDV) in European dairy sheep flocks. Hence, our main aim was to investigate the accuracy of analyzing anti-BDV antibodies in bulk-tank milk (BTM) in detecting the real BDV seroprevalence in dairy sheep flocks. Furthermore, the relevance of BDV to reproductive performance of dairy sheep flocks prompted us to search for the association between BDV seroprevalence and reproductive parameters. For these purposes, 34 flocks were selected based on different percentages of antibody inhibition (AIP) values in BTM as estimated by ELISA. Serum samples from 10 replacement lambs older than 6 mo, 10 ewes 1 to 2 yr old, and 10 ewes >2 yr old were collected and analyzed for the presence of anti-BDV antibodies by ELISA. A negative relationship between BDV AIP in BTM and within-flock seroprevalence was observed. Flocks with a high AIP (>80%) had an average of 2.5% seropositive animals; flocks with a moderate AIP (46-79%) had 11.4% seropositive animals; and finally, flocks with an AIP ¿45% showed a high flock seroprevalence (57.2%). Ten out of 34 flocks showed a high BDV seroprevalence in lambs, suggesting the presence of persistently infected animals in the flock. The observed AIP values in BTM from these likely BDV-infected flocks were indicative of a high seroprevalence. The analysis of reproductive-parameters data collected from these flocks showed no differences in fertility or prolificacy in relation to BDV circulation rates. Nonetheless, lamb mortality was significantly greater in flocks with low-moderate seroprevalence (10-30%), probably as a result of a first-time contact with BDV of previously naïve ewes. These findings suggest that testing of BTM samples may be useful in inferring the BDV seroprevalence in a flock.This work was funded by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA, RTA04-057) and Departamento de Medio Ambiente, Planificación Territorial, Agricultura y Pesca (DAPA) from the Basque Government, Spain. The authors thank Josune Arranz and Ina Beltrán de Heredia from NEIKER-Arkaute for their effort in compiling and revising the productive database. Francisco Ruiz-Fons is supported by a postdoctoral grant of the Instituto de Salud Carlos III of the Spanish Ministry of Health.Peer Reviewe

Estimation of Coxiella burnetii prevalence in dairy cattle in intensive systems by serological and molecular analyses of bulk-tank milk samples

A large-scale investigation on Coxiella burnetii was carried out in dairy cattle herds from a Q fever-endemic region to evaluate the degree of exposure to C. burnetii and to estimate prevalences. This study included all of the dairy cattle herds from the province of Bizkaia, Northern Spain (n=178). Herds were visited between September 2009 and February 2010, and 100mL of bulk-tank milk (BTM) per farm was collected to be analyzed by ELISA and PCR. Blood samples were also taken from about 15 animals randomly selected from each herd. One hundred nineteen of the 178 studied herds (66.9±6.9%) were positive for the presence of anti-C. burnetii antibodies in BTM. Serum samples from 1,306 cows, 654 heifers, and 502 calves were analyzed by ELISA, and cows showed a statistically significantly higher seroprevalence (12.3±1.8%) than heifers (1.1±0.8%) and calves (0.0±0.0%). Eighty-nine herds (50.0±7.3%) had at least 1 seropositive animal, but within-herd prevalences higher than 20% were only observed in 24 herds (13.5±5.0%). A significant correlation was observed between BTM ELISA sample-to-positive control ratios and within-herd seroprevalence, being higher when considering only cows (R 2=0.21). Animals from herds with negative BTM by ELISA showed a mean seroprevalence of 2.5%, whereas animals from herds with positive BTM samples had a statistically significantly higher seroprevalence (8.9%, F=19.7, degrees of freedom=1). The proportion of herds C. burnetii positive by BTM PCR was 51.7±7.3% (92/178). The widespread distribution of C. burnetii in cattle advocates for the implementation of Q fever control strategies.This work was supported by funding from Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA, Madrid, Spain; RTA 2009-00017-00), European Regional Development Fund (ERDF), and the Department of Agriculture of the Basque Government (Spain). I. Astobiza is the recipient of a predoctoral fellowship from the Department of Agriculture, Fisheries and Food of the Basque Government and A. Piñero is the recipient of a predoctoral fellowship from INIA.Peer Reviewe

Measuring antibody levels in bulk-tank milk as an epidemiological tool to search for the status of Coxiella burnetii in dairy sheep

Pooling samples may provide a valuable alternative to individual testing for pathogen surveillance purposes. We studied the reliability of measuring the level of antibodies against Coxiella burnetii in bulk-tank milk (BTM) to estimate the seroprevalence of C. burnetii in dairy sheep in 34 flocks. We then estimated the seroprevalence of C. burnetii in 154 dairy sheep flocks according to the level of antibodies in BTM. We tested for the accuracy of our estimation at the population level by comparing predicted mean C. burnetii flock seroprevalence with that obtained in another survey performed on the same population. Our findings showed that testing BTM by ELISA is a cost-effective and relatively good index of the seroprevalence of C. burnetii in dairy sheep and may be a useful tool for epidemiological surveillance at the population level.This work was supported by funding from INIA, FAU2006-00002-C04-01 and FEDER. F. Ruiz-Fons is supported by the Instituto de Salud Carlos III of the Spanish Ministry of Science and Innovation. Ianire Astobiza is the recipient of a predoctoral fellowship of the Department of Agriculture, Fisheries and Food of the Basque Government.Peer Reviewe