Crossing the Interspecies Barrier: Opening the Door to Zoonotic Pathogens

The number of pathogens known to infect humans is ever increasing. Whether such increase reflects improved surveillance and detection or actual emergence of novel pathogens is unclear. Nonetheless, infectious diseases are the second leading cause of human mortality and disability-adjusted life years lost worldwide [1], [2]. On average, three to four new pathogen species are detected in the human population every year [3]. Most of these emerging pathogens originate from nonhuman animal species

Differentially represented proteins in response to infection with Mycobacterium tuberculosis identified by quantitative serum proteomics in Asian elephants

Tuberculosis is a major global concern. Tuberculosis in wildlife is a risk for zoonotic transmission and becoming one of the challenges for conservation globally. In elephants, the number of cases is likely rising. The aim of this study was to identify proteins related to tuberculosis infection in elephants, which could then be used for the development of diagnostic tools and/or vaccines. A serum proteomics approach was used to characterize differentially represented proteins in response to Mycobacterium tuberculosis in Asian elephants (Elaphas maximus). Blood samples were collected from eight elephants, four of which were antibody positive for tuberculosis and four were antibody negative. Proteomics analysis identified 26 significantly dysregulated proteins in response to tuberculosis. Of these, 10 (38%) were identified as immunoglobulin and 16 (62%) as non-immunoglobulin proteins. The results provided new information on the antibody response to mycobacterial infection and biomarkers associated with tuberculosis and protective response to mycobacteria in Asian elephants. Protective mechanisms included defense against infection (Alpha- 1-B glycoprotein A1BG, Serpin family A member 1 SERPINA1, Transthyretin TTR), neuroprotection (TTR), and reduced risks of inflammation, infections, and cancer (SERPINA1, Keratin 10 KRT10). Using a translational biotechnology approach, the results provided information for the identification of candidate diagnostic, prognostic, and protective antigens for monitoring and control of tuberculosis in Asian elephants.La tuberculosis es una de las principales preocupaciones a nivel mundial. La tuberculosis en la fauna salvaje es un riesgo de transmisión zoonótica y se está convirtiendo en uno de los retos de la conservación a nivel mundial. En los elefantes, es probable que el número de casos aumente. El objetivo de este estudio era identificar las proteínas relacionadas con la infección por tuberculosis en los elefantes, que podrían utilizarse para el desarrollo de herramientas de diagnóstico y/o vacunas. Se utilizó un enfoque de proteómica sérica para caracterizar las proteínas representadas diferencialmente en respuesta a Mycobacterium tuberculosis en elefantes asiáticos (Elaphas maximus). Se recogieron muestras de sangre de ocho elefantes, cuatro de los cuales dieron positivo a los anticuerpos de la tuberculosis y cuatro fueron negativos a los anticuerpos. El análisis proteómico identificó 26 proteínas significativamente desreguladas en respuesta a la tuberculosis. De ellas, 10 (38%) se identificaron como inmunoglobulinas y 16 (62%) como proteínas no inmunoglobulínicas. Los resultados aportaron nueva información sobre la respuesta de los anticuerpos a la infección micobacteriana y los biomarcadores asociados a la tuberculosis y la respuesta protectora a las micobacterias en los elefantes asiáticos. Los mecanismos de protección incluían la defensa contra la infección (glicoproteína alfa-1-B, miembro 1 de la familia A de las serpinas SERPINA1, transtiretina TTR), la neuroprotección (TTR) y la reducción del riesgo de inflamación, infecciones y cáncer (SERPINA1, queratina 10 KRT10). Utilizando un enfoque de biotecnología traslacional, los resultados proporcionaron información para la identificación de antígenos candidatos de diagnóstico, pronóstico y protección para el seguimiento y control de la tuberculosis en elefantes asiáticos

Oral re-vaccination of Eurasian wild boar with Mycobacterium bovis BCG yields a strong protective response against challenge with a field strain

Background: Field vaccination trials with Mycobacterium bovis BCG, an attenuated mutant of M. bovis, are ongoing in Spain, where the Eurasian wild boar (Sus scrofa) is regarded as the main driver of animal tuberculosis (TB). The oral baiting strategy consists in deploying vaccine baits twice each summer, in order to gain access to a high proportion of wild boar piglets. The aim of this study was to assess the response of wild boar to re-vaccination with BCG and to subsequent challenge with an M. bovis field strain.Results: BCG re-vaccinated wild boar showed reductions of 75.8% in lesion score and 66.9% in culture score, as compared to unvaccinated controls. Only one of nine vaccinated wild boar had a culture-confirmed lung infection, as compared to seven of eight controls. Serum antibody levels were highly variable and did not differ significantly between BCG re-vaccinated wild boar and controls. Gamma IFN levels differed significantly between BCG re-vaccinated wild boar and controls. The mRNA levels for IL-1b, C3 and MUT were significantly higher in vaccinated wild boar when compared to controls after vaccination and decreased after mycobacterial challenge.Conclusions: Oral re-vaccination of wild boar with BCG yields a strong protective response against challenge with a field strain. Moreover, re-vaccination of wild boar with BCG is not counterproductive. These findings are relevant given that re-vaccination is likely to happen under real (field) conditions.Peer reviewedVeterinary Pathobiolog

Bovine Tuberculosis in Doñana Biosphere Reserve: The Role of Wild Ungulates as Disease Reservoirs in the Last Iberian Lynx Strongholds

Doñana National Park (DNP) in southern Spain is a UNESCO Biosphere Reserve where commercial hunting and wildlife artificial feeding do not take place and traditional cattle husbandry still exists. Herein, we hypothesized that Mycobacterium bovis infection prevalence in wild ungulates will depend on host ecology and that variation in prevalence will reflect variation in the interaction between hosts and environmental risk factors. Cattle bTB reactor rates increased in DNP despite compulsory testing and culling of infected animals. In this study, 124 European wild boar, 95 red deer, and 97 fallow deer were sampled from April 2006 to April 2007 and analyzed for M. bovis infection. Modelling and GIS were used to identify risk factors and intra and inter-species relationships. Infection with M. bovis was confirmed in 65 (52.4%) wild boar, 26 (27.4%) red deer and 18 (18.5%) fallow deer. In the absence of cattle, wild boar M. bovis prevalence reached 92.3% in the northern third of DNP. Wild boar showed more than twice prevalence than that in deer (p<0.001). Modelling revealed that M. bovis prevalence decreased from North to South in wild boar (p<0.001) and red deer (p<0.01), whereas no spatial pattern was evidenced for fallow deer. Infection risk in wild boar was dependent on wild boar M. bovis prevalence in the buffer area containing interacting individuals (p<0.01). The prevalence recorded in this study is among the highest reported in wildlife. Remarkably, this high prevalence occurs in the absence of wildlife artificial feeding, suggesting that a feeding ban alone would have a limited effect on wildlife M. bovis prevalence. In DNP, M. bovis transmission may occur predominantly at the intra-species level due to ecological, behavioural and epidemiological factors. The results of this study allow inferring conclusions on epidemiological bTB risk factors in Mediterranean habitats that are not managed for hunting purposes. Our results support the need to consider wildlife species for the control of bTB in cattle and strongly suggest that bTB may affect animal welfare and conservation

Evidence of the role of tick subolesin in gene expression

Background: Subolesin is an evolutionary conserved protein that was discovered recently in Ixodes scapularis as a tick protective antigen and has a role in tick blood digestion, reproduction and development. In other organisms, subolesin orthologs may be involved in the control of developmental processes. Because of the profound effect of subolesin knockdown in ticks and other organisms, we hypothesized that subolesin plays a role in gene expression, and therefore affects multiple cellular processes. The objective of this study was to provide evidence for the role of subolesin in gene expression.Results: Two subolesin-interacting proteins were identified and characterized by yeast two-hybrid screen, co-affinity purification and RNA interference (RNAi). The effect of subolesin knockdown on the tick gene expression pattern was characterized by microarray analysis and demonstrated that subolesin RNAi affects the expression of genes involved in multiple cellular pathways. The analysis of subolesin and interacting protein sequences identified regulatory motifs and predicted the presence of conserved protein kinase C (PKC) phosphorylation sites.Conclusion: Collectively, these results provide evidence that subolesin plays a role in gene expression in ticks.Peer reviewedVeterinary PathobiologyBiochemistry and Molecular Biolog

Spatial distribution and risk factors of Brucellosis in Iberian wild ungulates

<p>Abstract</p> <p>Background</p> <p>The role of wildlife as a brucellosis reservoir for humans and domestic livestock remains to be properly established. The aim of this work was to determine the aetiology, apparent prevalence, spatial distribution and risk factors for brucellosis transmission in several Iberian wild ungulates.</p> <p>Methods</p> <p>A multi-species indirect immunosorbent assay (iELISA) using <it>Brucella </it>S-LPS antigen was developed. In several regions having brucellosis in livestock, individual serum samples were taken between 1999 and 2009 from 2,579 wild bovids, 6,448 wild cervids and4,454 Eurasian wild boar (<it>Sus scrofa</it>), and tested to assess brucellosis apparent prevalence. Strains isolated from wild boar were characterized to identify the presence of markers shared with the strains isolated from domestic pigs.</p> <p>Results</p> <p>Mean apparent prevalence below 0.5% was identified in chamois (<it>Rupicapra pyrenaica</it>), Iberian wild goat (<it>Capra pyrenaica</it>), and red deer (<it>Cervus elaphus</it>). Roe deer (<it>Capreolus capreolus</it>), fallow deer (<it>Dama dama</it>), mouflon (<it>Ovis aries</it>) and Barbary sheep (<it>Ammotragus lervia</it>) tested were seronegative. Only one red deer and one Iberian wild goat resulted positive in culture, isolating <it>B. abortus </it>biovar 1 and <it>B. melitensis </it>biovar 1, respectively. Apparent prevalence in wild boar ranged from 25% to 46% in the different regions studied, with the highest figures detected in South-Central Spain. The probability of wild boar being positive in the iELISA was also affected by age, age-by-sex interaction, sampling month, and the density of outdoor domestic pigs. A total of 104 bacterial isolates were obtained from wild boar, being all identified as <it>B. suis </it>biovar 2. DNA polymorphisms were similar to those found in domestic pigs.</p> <p>Conclusions</p> <p>In conclusion, brucellosis in wild boar is widespread in the Iberian Peninsula, thus representing an important threat for domestic pigs. By contrast, wild ruminants were not identified as a significant brucellosis reservoir for livestock.</p

Seroprevalence and Risk Factors Associated to Mycobacterium bovis in Wild Artiodactyl Species from Southern Spain, 2006–2010

The control of bovine tuberculosis (bTB) is at a critical point in the last stage of eradication in livestock. Wildlife species recently have emerged infected with TB in Europe, particularly ungulates in the Iberian Peninsula. Epidemiological information regarding TB in wild ungulates including affected species, prevalence, associated risk factors and appropriate diagnostic methods need to be obtained in these countries

Research gap analysis on African swine fever

The most significant knowledge gaps in the prevention and control of African swine fever (ASF) were identified by the EU Veterinary services and other stakeholders involved in pig production and wild boar management through an online survey. The respondents were asked to identify the major research needs in order to improve short-term ASF risk management. Four major gaps were identified: ‘wild boar’, ‘African swine fever virus (ASFV) survival and transmission’, ‘biosecurity’ and ‘surveillance’. In particular, the respondents stressed the need for better knowledge on wild boar management and surveillance, and improved knowledge on the possible mechanism for spread and persistence of ASF in wild boar populations. They indicated the need for research on ASFV survival and transmission from the environment, different products such as feed and feed materials, and potential arthropod vector transmission. In addition, several research topics on biosecurity were identified as significant knowledge gaps and the need to identify risk factors for ASFV entry into domestic pig holdings, to develop protocols to implement specific and appropriate biosecurity measures, and to improve the knowledge about the domestic pig–wild boar interface. Potential sources of ASFV introduction into unaffected countries need to be better understood by an in-depth analysis of the possible pathways of introduction of ASFV with the focus on food, feed, transport of live wild boars and human movements. Finally, research on communication methods to increase awareness among all players involved in the epidemiology of ASF (including truck drivers, hunters and tourists) and to increase compliance with existing control measures was also a topic mentioned by all stakeholders