Molecular characterization of Mycobacterium tuberculosis complex isolates from wild ungulates in south-central Spain

A review of bovine tuberculosis in the kafue basin ecosystem

The Kafue basin ecosystem is the only remaining natural habitat for the endangered Kafue lechwe antelope (Kobus leche Kafuensis). However, hydroelectricity power production, large-scale sugar plantations, commercial fishing and increasing livestock production are threatening its natural existence and sustainability. Further, increasing human settlements within and around the Kafue basin have resulted in decreased grazing grounds for the Kafue lechwe antelopes despite a corresponding increase in cattle population sharing the same pasture. Baseline epidemiological data have persistently reported findings of bovine tuberculosis (BTB) in both wild and domestic animals, although these have been deficient in terms of describing direct evidence in the role of either lechwe antelopes or cattle in the reported observations. Despite the current literature being deficient in establishing the casual role and transmission patterns of BTB, a bimodal route of infection at the livestock/wildlife interface has been postulated. Likewise, it is not known how much of (BTB) has the potential of causing disease in humans. This paper, seeks to underline those aspects that need further research and update available data on BTB in the Kafue basin with regards to the prevalence, distribution, risk factors, threats on wildlife conservation, livestock production, public health implications, and possible mitigatory measures.

Advances in molecular diagnostics for Mycobacterium bovis

The two most important molecular diagnostic techniques for bovine tuberculosis are the polymerase chain reaction (PCR) because of its rapid determination of infection, and DNA strain typing because of its ability to answer important epidemiological questions. PCR tests for Mycobacterium bovis have been improved through recent advances in PCR technology, but still lack the sensitivity of good culture methods, and in some situations are susceptible to giving both false negative and false positive results. Therefore, PCR does not usually replace the need for culture, but is used to provide fast preliminary results. DNA typing of M. bovis isolates by restriction endonuclease analysis (REA) was developed 25 years ago in New Zealand, and remains an important tool in the New Zealand control scheme, where the typing results are combined with other information to determine large and expensive possum poisoning operations. A range of other DNA typing systems developed for M. bovis in the 1990 s have assisted epidemiological investigations in some countries but are now less commonly used. Variable number tandem repeat (VNTR) typing and spoligotyping, either alone or together, have now become the preferred approaches as they are robust and amenable to electronic analysis and comparison. Spoligotyping gives only moderate discrimination but can be easily applied to large numbers of isolates, and VNTR typing provides better discrimination than all other methods except for REA. While the current typing techniques are sufficient for most epidemiological purposes, more discriminating methods are likely to become available in the near future.

Fine-tuning the space, time, and host distribution of mycobacteria in wildlife

Background

We describe the diversity of two kinds of mycobacteria isolates, environmental mycobacteria and Mycobacterium bovis collected from wild boar, fallow deer, red deer and cattle in Doñana National Park (DNP, Spain), analyzing their association with temporal, spatial and environmental factors.

Results

High diversity of environmental mycobacteria species and M. bovis typing patterns (TPs) were found. When assessing the factors underlying the presence of the most common types of both environmental mycobacteria and M. bovis TPs in DNP, we evidenced (i) host species differences in the occurrence, (ii) spatial structuration and (iii) differences in the degree of spatial association of specific types between host species. Co-infection of a single host by two M. bovis TPs occurred in all three wild ungulate species. In wild boar and red deer, isolation of one group of mycobacteria occurred more frequently in individuals not infected by the other group. While only three TPs were detected in wildlife between 1998 and 2003, up to 8 different ones were found during 2006-2007. The opposite was observed in cattle. Belonging to an M. bovis-infected social group was a significant risk factor for mycobacterial infection in red deer and wild boar, but not for fallow deer. M. bovis TPs were usually found closer to water marshland than MOTT.

Conclusions

The diversity of mycobacteria described herein is indicative of multiple introduction events and a complex multi-host and multi-pathogen epidemiology in DNP. Significant changes in the mycobacterial isolate community may have taken place, even in a short time period (1998 to 2007). Aspects of host social organization should be taken into account in wildlife epidemiology. Wildlife in DNP is frequently exposed to different species of non-tuberculous, environmental mycobacteria, which could interact with the immune response to pathogenic mycobacteria, although the effects are unknown. This research highlights the suitability of molecular typing for surveys at small spatial and temporal scales.

Eurasian wild boar response to skin-testing with mycobacterial and non-mycobacterial antigens

Eurasian wild boar (Sus scrofa) are able to maintain bovine tuberculosis (bTB) in the wild and are most probably able to transmit the disease to other species, thus acting as a true wildlife reservoir. Translocation of wild boar is a common practice in European countries. Therefore, identifying effective tools for bTB diagnosis in living wild boar is crucial for the implementation of control measures. We describe for the first time the sex and origin related differences in the skin-test response to mycobacterial antigens (bPPD and aPPD) and to a non-mycobacterial antigen (PHA, a plant derived mitogen) in wild and farmed wild boar, and used a small sample of known M. bovis infected wild boar to establish whether skin-testing is an option for bTB diagnosis in living wild boar. The highest skinfold increase response was detected at the PHA injection site, evidencing that the PHA test could be useful in monitoring cell mediated immunity (CMI) in wild boar populations. A clear age-increasing trend of the PHA response indicated that age should be taken into account when measuring CMI in wild boar. Origin related differences in the response against mycobacterial antigens could reflect differential exposure to mycobacterial antigens. Skin testing in BCG immunized wild boar showed low sensitivity (43-57%), while the sensitivity was good in the culture positive controls (75-100%), depending on the reading criterion. Specificity improved when the criterion was a response to bPPD larger than 2 mm and bPPD response larger than aPPD response (77%). Although a limited sample, our results indicated the potential of skin test as a bTB diagnostic tool in Eurasian wild boar. However, handling of wild boar is dangerous, specificity is low, and more effort is needed in order to define the sensitivity of this technique.

PallarésFrancisco F. Use of Real-Time and Classic Polymerase Chain Reaction Assays for the Diagnosis of Porcine Tuberculosis in Formalin-Fixed, Paraffin-Embedded Tissues

The current study was carried out to set up a fast and specific technique for porcine tuberculosis diagnosis in formalin-fixed, paraffin-embedded tissues. A retrospective study was carried out using 54 samples fixed in 10% neutral buffered formalin from 29 slaughtered Iberian pigs. Most of the pigs showed tissue samples positive to immunohistochemical staining (70.4%), and mycobacteria were detected within or near the necrotic cores of the lesions. However, diagnosis by this technique was time-consuming and tedious because of the paucibacillar nature of porcine tuberculous lesions. Classic polymerase chain reaction (PCR) was unsuccessful in mycobacteria genome amplification in all of the examined samples; however, real-time PCR amplified the mycobacteria genome in 23 of 29 examined pigs, identifying the Mycobacterium tuberculosis complex in all but one, which amplified Mycobacterium avium complex. Moreover, when reamplification of the DNA was performed, classic PCR amplified the mycobacteria genome in all the examined pigs (29/29), identifying the M. tuberculosis complex in 28 of 29 studied pigs and M. avium complex in only 1 pig. Results of the current study point out that both real-time and classic PCR assays, with genome reamplification, represent sensitive, fast, and specific diagnostic tools for porcine tuberculosis in formalin-fixed, paraffin-embedded tissues.

Impact of major histocompatibility complex class II polymorphisms on Iberian red deer parasitism and life history traits

Host genetic diversity plays an important role in buffering populations against pathogens. We characterized the allelic diversity at the second exon of the b (DRB-2) chain of the major histocompatibility complex class II (MHC-II) locus in a population of Iberian red deer (Cervus elaphus hispanicus) and its impact on parasitism by macroparasites, on a microparasite causing tuberculosis, and on relevant life history traits (spleen size and body condition). No DRB-2 haplotype conferred general resistance or susceptibility against all parasites. However, specific significant correlations were found between some DRB-2 haplotypes and specific parasites. We also detected associations between DRB-2 haplotypes and body condition and spleen size after controlling for body size, sex and age. Our results evidenced a functional significance of MHC-II genes in the defence of Iberian red deer against parasites. These results also support a role of MHC-II as a fitness-enhancing genetic element which can be mediated by parasite effects on life traits with a genetic basis. We conclude that MHC immunogenetic studies may assess management decisions in Iberian red deer because (i) loss of genetic diversity may lead to increased disease occurrence, and (ii) MHC genes are ecologically relevant since they underlie host infection rates and life history traits.

Classification of worldwide bovine tuberculosis risk factors in cattle: a stratified approach

The worldwide status of bovine tuberculosis (bTB) as a zoonosis remains of great concern. This article reviews the main risk factors for bTB in cattle based on a three-level classification: animal, herd and region/country level. A distinction is also made, whenever possible, between situations in developed and developing countries as the difference of context might have consequences in terms of risk of bTB. Recommendations are suggested to animal health professionals and scientists directly involved in the control and prevention of bTB in cattle. The determination of Millenium Development Goals for bTB is proposed to improve the control/eradication of the disease worldwide.

Feline leukemia virus and other pathogens as important threats to the survival of the critically endangered Iberian lynx (Lynx pardinus)

BACKGROUND

The Iberian lynx (Lynx pardinus) is considered the most endangered felid species in the world. In order to save this species, the Spanish authorities implemented a captive breeding program recruiting lynxes from the wild. In this context, a retrospective survey on prevalence of selected feline pathogens in free-ranging lynxes was initiated.

METHODOLOGY/ PRINCIPAL FINDINGS

We systematically analyzed the prevalence and importance of seven viral, one protozoan (Cytauxzoon felis), and several bacterial (e.g., hemotropic mycoplasma) infections in 77 of approximately 200 remaining free-ranging Iberian lynxes of the Doñana and Sierra Morena areas, in Southern Spain, between 2003 and 2007. With the exception of feline immunodeficiency virus (FIV), evidence of infection by all tested feline pathogens was found in Iberian lynxes. Fourteen lynxes were feline leukemia virus (FeLV) provirus-positive; eleven of these were antigenemic (FeLV p27 positive). All 14 animals tested negative for other viral infections. During a six-month period in 2007, six of the provirus-positive antigenemic lynxes died. Infection with FeLV but not with other infectious agents was associated with mortality (p<0.001). Sequencing of the FeLV surface glycoprotein gene revealed a common origin for ten of the eleven samples. The ten sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Endogenous FeLV sequences were not detected.

CONCLUSIONS/SIGNIFICANCE

It was concluded that the FeLV infection most likely originated from domestic cats invading the lynx's habitats. Data available regarding the time frame, co-infections, and outcome of FeLV-infections suggest that, in contrast to the domestic cat, the FeLV strain affecting the lynxes in 2007 is highly virulent to this species. Our data argue strongly for vaccination of lynxes and domestic cats in and around lynx's habitats in order to prevent further spread of the virus as well as reduction the domestic cat population if the lynx population is to be maintained.

Comparison of Three Immunological Diagnostic Tests for the Detection of Avian Tuberculosis in Naturally Infected Red Deer (Cervus Elaphus)

Cases of tuberculosis due to Mycobacterium avium subsp. avium in 52 adult red deer ( Cervus elaphus) from a farm were studied using different diagnostic techniques. Immunological probes consisted of the comparative cervical tuberculin (CCT) skin test, the interferon-γ (IFN-γ) assay, and 2 enzyme-linked immunosorbent assays (ELISAs) employing either avian purified protein derivatives or protoplasmatic antigen (PPA-3) as antigens. Three of the animals were euthanized due to severe weakness, loss of weight, and emaciation. Macroscopically, the 3 animals showed tuberculous lesions located mainly in lymph nodes of the digestive system and small intestine but also in other organs and lymph nodes. Polymerase chain reaction was carried out on samples from the 3 deer using primers to detect IS901, IS900, and IS6110, specific for Mycobacterium avium subsp. avium, Mycobacterium avium subsp. paratuberculosis, and Mycobacterium tuberculosis complex, including Mycobacterium bovis, respectively. The last 2 agents cause pathologies very similar to avian tuberculosis in deer. The 3 deer were strongly positive by both ELISAs, slightly positive by the IFN-γ test, and 1 of 2 was positive by the CCT test. As with domestic ruminants, ELISA could detect deer in an advanced stage of infection, with large numbers of mycobacteria.

Gene expression profiles of European wild boar naturally infected with Mycobacterium bovis

Global gene expression profiles were analyzed in European wild boar naturally infected with Mycobacterium bovis. Spleen RNA was extracted from 23 M. bovis-infected and 17 uninfected animals and analyzed using a Pigoligoarray representing 20,400 genes. Differentially expressed sequences (N=161) were identified affecting cellular processes such as apoptosis, cell communication and signal transduction, cell growth and/or maintenance, cytoskeleton organization and biogenesis, DNA repair, immune response, metabolism and energy pathways, protein metabolism, regulation of cell proliferation, regulation of gene expression, regulation of nucleic acid metabolism, regulation of physiological processes, and transport. Real-time RT-PCR analysis of mRNA levels was used to corroborate microarray results of selected genes. Immune response genes were among the most represented differentially expressed sequences and were selected for further discussion. Beta-defensin 129, T-cell surface glycoprotein CD8 and B-cell receptor-associated protein 29 were overexpressed in infected animals. Lower expression levels of the immune response genes galectin-1, complement component C1qB and certain HLA class I and class II histocompatibility antigens and immunoglobulin chains were found in infected animals. This study identified new mechanisms by which naturally infected European wild boar respond to M. bovis infection and how the pathogen circumvents host immune responses to establish infection. Gene expression studies in naturally infected wildlife reservoirs of bovine tuberculosis are important for functional genomics and vaccine studies to aid in disease control in wildlife.

High prevalence of antibodies against Chlamydiaceae and Chlamydophila abortus in wild ungulates using two "in house" blocking-ELISA tests

Few data are available on the prevalence and relevance of chlamydiae in wild mammals, and even fewer studies have been conducted to determine the prevalence of Chlamydophila abortus in wildlife hosts, most probably due to the absence of suitable species-specific serological assays for testing sera from wild animals. In light of this, we have developed two in-house blocking-ELISA tests for detection of antibodies against Chlamydiaceae and C. abortus in wild ungulates, and analyzed the relationship between geographical and biological factors and the prevalence of antibodies against Chlamydiaceae and C. abortus in 434 wild ungulates from Spain, including sera from European wild boar, Red deer, Fallow deer, Roe deer, Mouflon, Barbary sheep, Southern chamois, and Iberian ibex. Serology revealed that 41.7+/-4% of the sera were positive for the b-ELISA-LPS (Chlamydiaceae-specific) and 18.9+/-3% for the b-ELISA-rPOMP (C. abortus-specific). Antibodies against Chlamydiaceae lipopolysaccharide (LPS) were detected in sera from all eight ungulate species, the prevalence ranging from 23 to 60%. Iberian ibex was the only wild ungulate not showing seropositivity to the C. abortus specific polymorphic outer membrane protein (POMP). The prevalence of anti-POMP antibodies in the other seven wild ungulate species ranged from 7 to 40%. While significant seroprevalence differences were detected among species and among sampling regions, no effect of age and sex was observed. The high prevalence levels found should be considered with regards to livestock and human health, and warrant further research.

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.

Influence of methylmalonyl-CoA mutase alleles on resistance to bovine tuberculosis in the European wild boar (Sus scrofa)

An association study was carried out to examine the influence of methylmalonyl-CoA mutase (MUT) polymorphisms on the susceptibility of a well-studied wild boar population from southern Spain to develop bovine tuberculosis (bTB). To this end, we examined polymorphisms at a closely linked dinucleotide microsatellite flanking exon 2 of the MUT gene in 37 wild boars with bTB and 36 non-infected individuals. The microsatellite showed low polymorphism in the studied population, with only three alleles (MUTm-A, MUTm-B and MUTm-C) found, in contrast to the 11 alleles previously reported for domestic pigs. Our case-control study showed that the MUTm-B allele was associated with disease in a dominant pattern (odds ratio = 3.36; 95% CI = 1.05-10.72; P = 0.04), while the MUTm AA genotype appeared to have a protective effect against bTB infection (odds ratio = 4.33; 95% CI = 1.20-14.96; P = 0.02). Interestingly, infected wild boars heterozygous for MUTm AB are at an advantage (11-fold) to contain the systemic spread of the disease when compared to other genotypes, implying that a balanced polymorphism may be present in the population. These results strengthen previous observations regarding the importance of the MUT gene on bTB resistance in wild boars and indicate that polymorphisms at this locus will influence the risk of acquiring and maintaining bTB in the studied population.

Isolation and characterisation of Rhodococcus equi from submaxillary lymph nodes of wild boars (Sus scrofa)

Rhodococcus equi has been isolated from the submaxillary lymph nodes of domesticated pigs, but little is known about the presence of R. equi in wild boars. The aim of the study was the evaluation of the incidence of R. equi in wild boars and the characterisation of them. Of 482 submaxillary lymph nodes of wild boars shot in 39 settlements throughout Hungary, R. equi was isolated from 60 specimens, and plasmid types of 82 isolates were examined. The isolates were tested for the presence of 15-17-kDa (VapA) and 20-kDa virulence-associated protein antigen (VapB) genes by polymerase chain reaction (PCR). Plasmid DNAs were isolated and analysed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. None of the 82 isolates contained vapA gene but 21 isolates (25.6%) were positive for vapB gene showing 827bp product of the expected size in the PCR amplification. Sixty-one strains (74.4%) did not contain plasmid. The 21 isolates of intermediate virulence contained virulence plasmids that were identified as types 1 (1 isolate), 5 (16 isolates), 21 (1 isolate), and three new distinct plasmid variants (1-1-1 isolate), respectively. On the basis of restriction digestion patterns of plasmid DNAs, we tentatively designated the new variants as types 25-27, respectively. The prevalence of R. equi strains of intermediate virulence among the isolates originated from the submaxillary lymph nodes of wild boars (25.6%) is very similar to those of domestic pigs (26.8%) in Hungary, and plasmid type 5 is the predominating one in both groups. This is the first report of isolation of VapB-positive R. equi from wild boars in the world.

Spoligotype diversity of Mycobacterium bovis and Mycobacterium caprae animal isolates

The genetic diversity of 283 Mycobacterium bovis (M. bovis) and 10 Mycobacterium caprae (M. caprae) strains, isolated between 2002 and 2007 from cattle, goat, red deer and wild boar from six different geographical regions of Portugal was investigated by spoligotyping. The technique showed a good discriminatory power (Hunter-Gaston Index, h=0.9) for the strains, revealing 29 different patterns. One pattern (SB0121) was clearly predominant, accounting for 26.3% of the isolates; ten patterns, representing 20.7% of the isolates, had never been reported previously. Multiple spoligotypes were detected in thirteen cattle and one goat herd, most of which were found in beef cattle and extensive management regions, suggesting different infection sources. With the exception of two spoligotypes, those in wildlife species were also found in domestic species.

Differential expression of inflammatory and immune response genes in mesenteric lymph nodes of Iberian red deer (Cervus elaphus hispanicus) naturally infected with Mycobacterium bovis

Little information is available about gene expression in natural mycobacterial infection of wildlife species. Iberian red deer can serve as reservoir of Mycobacterium bovis in Spain, thus increasing the risk of bovine tuberculosis (bTB) in humans and cattle. Herein, we characterized the differential expression of inflammatory and immune response genes in mesenteric lymph nodes of deer naturally infected with M. bovis using microarray hybridization. Results were validated by determination of serum protein concentrations and/or real-time RT-PCR. Of the 600 genes that were analyzed in the microarray, 17 genes displayed an expression fold change greater than 1.7 in infected or uninfected deer (P0.05). These genes included tight junction proteins, IL-11R, bactenecin, CD62L, CD74, desmoglein, IgA and IgM that constitute new findings and suggest new mechanisms by which M. bovis may modulate host inflammatory and immune responses. These results contribute to our basic understanding of the mechanisms of pathogenesis and immunity to natural mycobacterial infections and may have important implications for the control of bTB.

Comparative genomics and proteomics to study tissue-specific response and function in natural Mycobacterium bovis infections

Bovine tuberculosis (bTB) is an established zoonotic disease which affects cattle and wildlife worldwide and new strategies are required to control and eradicate the disease. The European wild boar (Sus scrofa) is a major reservoir of bTB in Spain. The objective of this paper was to review tissue-specific response and function of mandibular lymph nodes (MLN) and oropharyngeal tonsils (OT) in European wild boar naturally infected with Mycobacterium bovis. Genomics and proteomics data were used to compare differential gene expression and global protein patterns in OT and MLN of M. bovis-infected and uninfected European wild boar and the results were analyzed considering previous reports of experimental infections in laboratory and domestic animals. The results showed tissue-specific differences in OT and MLN in response to M. bovis infection. Tissue-specific differences in gene expression and protein profiles suggested different functions for OT and MLN during mycobacterial infection and provided information to characterize the pathobiology of M. bovis infection in European wild boar with important implications for the control of bTB in Spain. The characterization of molecular events in tissues that play different roles during mycobacterial infection in naturally infected individuals may be relevant to understand the pathobiology of M. bovis infection and to design effective strategies for the control of bTB in wildlife reservoirs.

Wild deer as a source of infection for livestock and humans in the UK

Wild deer can feature in the epidemiology of a wide range of livestock and human diseases in the United Kingdom by representing a source of disease via various transmission routes. This review highlights current and possible future infections of deer in the UK which may have an impact on livestock and/or human health. Increases in deer abundance as well as range expansion are likely to exacerbate the potential for disease persistence due to the formation of multi-species deer assemblages, which may act as disease reservoirs. Climatic changes are likely to have a direct impact on the presence and abundance of various pathogens and their vectors, so that with a warming climate exotic diseases may play a role in future UK livestock and wildlife disease management. This paper highlights the need for a monitoring strategy for wildlife diseases, in particular infections in wild deer, in the UK.

Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden

In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.

Lesions associated with Mycobacterium tuberculosis complex infection in the European wild boar

Information on lesion distribution and characteristics is essential to determine the significance of a species as a reservoir host for tuberculosis (TB). Herein, we describe the extension and distribution of lesions in 127 Mycobacterium tuberculosis Complex culture positive European wild boars (Sus scrofa), and use this information to discuss the role of this wildlife species in TB epidemiology in Mediterranean Spain. Macroscopic TB-compatible lesions were detected in 105 of 127 wild boars (82.68%). Only microscopic lesions were found in 11 wild boars (8.66%). Lesions were not evident in 11 wild boars (8.66%). A total of 49 wild boars had lesions confined to one anatomical region (42.2%, localized TB), while 67 animals had lesions in more than one anatomical region (57.8%, generalized TB). Head lymph nodes (LNs), particularly the mandibular LNs, were most frequently affected (107/116, 92.24%), and 43 wild boar had only mandibular LN lesions. Histopathology evidenced TB lesions in 38.1% of the lungs, 23% of the livers and 13% of the spleens examined. Mammary gland lesions were observed in three cases. When TB lesions were localized, granulomas characterized by a mixed inflammatory cell population were more predominant, whereas strongly necrotic-calcified granulomas were more prevalent in generalized cases of TB infection. Large lesions in more than one anatomical region were more frequent among juveniles. The histopathological characteristics of the tuberculous reaction and the associated tissue damage in various organs, together with the gross pathology, indicate that at least those wild boar with large lesions and generalized infections have the potential to excrete mycobacteria by several routes. This finding, in the context of unusually high densities of wild boar and fencing and feeding, reinforces the suggestion that wild boar can act as a true TB reservoir under the particular circumstances of Mediterranean Spain. Further studies on the routes of excretion as well as the effect of altering management methods would be of interest to confirm the role of wild boar in TB epidemiology in Spain.

Improvement of spoligotyping with additional spacer sequences for characterization of Mycobacterium bovis and M. caprae isolates from Spain

Spoligotyping is a typing tool used worldwide for epidemiological studies on Mycobacterium tuberculosis complex organisms; however it has received little attention regarding improvement of its discriminatory power (DP). In this study, we have evaluated a spoligotyping membrane prepared with 25 novel spacer sequences selected from a previous study [van der Zanden AG, Kremer K, Schouls LM. Improvement of differentiation and interpretability of spoligotyping for Mycobacterium tuberculosis complex isolates by introduction of new spacer oligonucleotides. J Clin Microbiol 2002;40:4628-39] on 308 M. bovis and 88 M. caprae Spanish isolates in comparison with the traditional spoligotyping membrane. The results obtained by combining the two membranes together revealed an improvement of 45 patterns instead of 31. The spacers used in the second membrane were able to distinguish 8 out of the 16 M. bovis types that had more than one isolate. Seven of these types were differentiated into two subtypes with the second-generation membrane, while spb-7, the most prevalent in Spain, was further differentiated into eight subtypes. This second-generation membrane also differentiates M. bovis from M. caprae. A set of 39 spacers (1, 2, 4-8, 10-15, 17-21, 23, 26-32, 37, 44-49, 51-54, 56 and 57) contain all the DP for both M. bovis and M. caprae isolates; and a set of 35 spacers (1, 2, 4-8, 10-15, 17-21, 26-32, 37, 44-48, 52-54 and 57) had all the DP for the M. bovis isolates. Our results show that the research on new spacers and the design of a new membrane may be useful for epidemiological studies of M. bovis and M. caprae isolates.

Risk analysis and bovine tuberculosis, a re-emerging zoonosis

The widespread of immunodeficiency with AIDS, the consequence of poverty on sanitary protection and information at both individual and state levels lead control of tuberculosis (TB) to be one of the priorities of World Health Organization programs. The impact of bovine tuberculosis (BTB) on humans is poorly documented. However, BTB remains a major problem for livestock in developing countries particularly in Africa and wildlife is responsible for the failure of TB eradication programs. In Africa, the consumption of raw milk and raw meat, and the development of bushmeat consumption as a cheap source of proteins, represent one of the principal routes for human contaminations with BTB. The exploration of these different pathways using tools as participatory epidemiology allows the risk analysis of the impact of BTB on human health in Africa. This analysis represents a management support and decision tool in the study and the control of zoonotic BTB.

Risk factors associated with the prevalence of tuberculosis-like lesions in fenced wild boar and red deer in south central Spain

In recent decades the management of large game mammals has become increasingly intensive in south central Spain (SCS), resulting in complex epidemiological scenarios for disease maintenance, and has probably impeded schemes to eradicate tuberculosis (TB) in domestic livestock. We conducted an analysis of risk factors which investigated associations between the pattern of tuberculosis-like lesions (TBL) in wild boar (Sus scrofa) and red deer (Cervus elaphus) across 19 hunting estates from SCS and an extensive set of variables related to game management, land use and habitat structure. The aggregation of wild boar at artificial watering sites was significantly associated with an increasing risk of detecting TBL in both species, which probably relates to enhanced opportunities for transmission. Aggregation of wild boar at feeding sites was also associated with increased risks of TBL in red deer. Hardwood Quercus spp. forest availability was marginally associated with an increased risk of TB in both species, whereas scrubland cover was associated with a reduced individual risk of TBL in the wild boar. It is concluded that management practices that encourage the aggregation of hosts, and some characteristics of Mediterranean habitats could increase the frequency and probability of both direct and indirect transmission of TB. These findings are of concern for both veterinary and public health authorities, and reveal tuberculosis itself as a potential limiting factor for the development and sustainability of such intensive game management systems in Spanish Mediterranean habitats.

Does chemical composition of antler bone reflect the physiological effort made to grow it?

In a previous study, antler bone chemical composition was found to differ between base and tip. If such variation is in part due to the physiological effort made to grow the antler, composition trends should differ between antlers from deer population differing in mineral or food availability, or body reserves. To assess this, we examined cortical thickness and bone composition along the antler shaft, and compared trends between antlers from two populations: captive, well-fed, health-managed deer (n=15), and free-ranging deer with lower food quality and no health treatment (n=10). Significant and clear divergent trends supporting greater physiological exhaustion in free-ranging deer and high or moderate predictive models were found for cortical thickness (R(2)=61.8%), content of Na (R(2)=68.6%), Mg (R(2)=56.3%), K (R(2)=40.0%), and Zn (34.6%); lower predictive power was found for protein (R(2)=25.6%) and ash content (R(2)=19.5%); and poor predictive power was found for Ca (R(2)=4.3%), Fe (R(2)=11.1%), and Si (R(2)=4.7%). A second part of the study assessed similar antler structures grown at the beginning (brow tine) and end (top tine) of antler growth within captive deer. Greater cortical thickness and ash content was found for brow tine, as well as a smaller protein, K and Mg content. In contrast, no difference was found for Ca, Na, Zn, Fe or Si. The results suggest that thickness and mineral composition reflect the physiological effort made to build antler bone.

The importance of parasite life history and host density in predicting the impact of infections in red deer

We studied a macroparasite (Elaphostrongylus cervi, Nematoda) and a microparasite infection (tuberculosis, TB) in red deer (Cervus elaphus) across different populations where managers manipulated host condition, density and aggregation by providing supplemental food. We aimed to test whether and, if so, how persistence and transmission of both parasites differentially varied as host body condition and population density varied. We took account of sex, as red deer life history greatly concerns sex-related traits. Changes in host factors had different consequences for the spread of each parasite type. Individual presence of tuberculosis was positively associated with host density, whereas E. cervi abundance negatively related to host density and enhanced body condition. There was lack of body condition density dependence; and body condition was mainly dependent on the amount of supplemental food provided, but also on habitat quality descriptors. Overall, our results suggest that body condition was improved at the cost of increased host contact rates, which implied an ecological trade-off between acquiring resources to cope with E. cervi, a macroparasite, and concurrent exposure to mycobacteria. By the simultaneous study of both infections, this research suggests that the effects of changes in host number and population structure on disease spread and persistence need to take into account variation in life histories of the parasites. These findings also raise concern about the ecological consequences of diseases and management of wildlife on host life history.

Proteomic and transcriptomic analyses of differential stress/inflammatory responses in mandibular lymph nodes and oropharyngeal tonsils of European wild boars naturally infected with Mycobacterium bovis

Differential stress/inflammatory responses were characterized at the mRNA and protein levels in mandibular lymph nodes (MLN) and oropharyngeal tonsils of European wild boars (Sus scrofa), naturally infected with Mycobacterium bovis. Suppression-subtractive hybridization combined with immunohistochemistry and/or quantitative real-time RT-PCR were used to identify and characterize abundant stress/inflammatory gene sequences differentially expressed in tuberculous (TB+) wild boars. Genes identified in MLN and tonsils corresponded to serum amyloid A, arginase I, osteopontin, lysozyme, annexin I, and heat shock proteins, respectively. Global protein patterns in MLN and tonsils were compared between TB+ and nontuberculous (TB-) boars by 2-DE and MALDI-TOF MS. Five proteins, including stress/inflammatory proteins annexin V, serum albumin, and apolipoprotein A1 were found at lower levels in MLN of TB+ boars. Manganese superoxide dismutase was found up-regulated in MLN of TB+ boars. Five proteins, including creatine kinase and MHC class II antigens were found up-regulated in tonsils of TB+ boars. These results demonstrated differential stress/inflammatory responses in wild boars naturally infected with M. bovis and suggest possible markers of tuberculosis in this species that may prove useful for future studies of host-pathogen interactions and for diagnostics and vaccine development.

The new mycobacteria: an update

The continuous evolution of mycobacterial taxonomy may represent a source of confusion for laboratories and clinicians. Apart from the obvious pathogenic strains of the Mycobacterium tuberculosis complex, Mycobacterium leprae and Mycobacterium ulcerans, the role of other mycobacteria may be associated with varying conditions ranging from contamination to specific disease processes. Of the more than 120 mycobacterial species recognized currently, very few have not been reported as pathogenic in humans or animals. Although the attempt to keep pace with the steadily increasing number of mycobacterial species seems hopeless, a careful review of the recent literature relevant to the newly described species may be advantageous. The aim of this present update is to provide epidemiological and clinical information along with major phenotypic and genotypic characteristics of the species described in the last 3 years.

Molecular epidemiology of multidrug-resistant Mycobacterium bovis isolates with the same spoligotyping profile as isolates from animals

PCR-based characterization techniques have been adopted in most laboratories for Mycobacterium bovis typing. We report a molecular characterization of human multidrug-resistant M. bovis isolates and three bovine isolates that share the spoligotyping profile. The analysis of the direct repeat region showed that both groups differed in the presence of spacers not included in the current membrane. They were also distinguished by two out of the nine mycobacterial interspersed repetitive unit variable-number tandem repeat loci tested, indicating that the human infection was not acquired from the cattle from which isolates were obtained. These results highlight that a combination of techniques is required for appropriate discrimination, even for those spoligotypes that have a low frequency.

The Application of Reproductive Technologies to Natural Populations of Red Deer

Over the past decade, there has been increasing interest in the application of reproductive technology to the conservation and management of natural populations of deer. The application of assisted reproduction technologies within natural population of deer is in its infancy. However, its future potential is enormous, particularly in relation to genetic management or conservation. This paper reviews the present state of such technologies for a wild subspecies of red deer, the Iberian red deer (Cervus elaphus hispanicus), by discussing the major components of oestrous synchronization, semen collection/cryopreservation and insemination techniques. In addition, findings made during the course of studies on natural populations have enormous potential for the understanding of novel reproductive mechanism that may not be uncovered by livestock or human studies. A summary of these results are also reviewed here.

Estimation of European wild boar relative abundance and aggregation: a novel method in epidemiological risk assessment

Wild boars are important disease reservoirs. It is well known that abundance estimates are needed in wildlife epidemiology, but the expense and effort required to obtain them is prohibitive. We evaluated a simple method based on the frequency of faecal droppings found on transects (FBII), and developed a spatial aggregation index, based on the runs test statistic. Estimates were compared with hunting data, and with porcine circovirus and Aujeszky's disease virus seroprevalences and Mycobacterium tuberculosis complex and Metastrongylus spp. prevalence. The FBII and the aggregation index were correlated with the hunting index, but both of the former estimates correlated better than the latter with the disease prevalences. Hence, at least in habitats with high wild boar densities, the FBII combined with the aggregation index constitutes a cheap and reliable alternative for wild boar abundance estimation that can be used for epidemiological risk assessment, even outside the hunting season and in areas with no available data on hunting activities.

Ixodid ticks parasitizing Iberian red deer (Cervus elaphus hispanicus) and European wild boar (Sus scrofa) from Spain: Geographical and temporal distribution

Commercial hunting of Spanish wild ungulates has made them an important economic resource. Wild ungulates may have an important role in the maintenance of ixodid tick populations, and also as reservoirs of pathogens. We studied the ixodid ticks that parasitize Iberian red deer and European wild boar from Spain. Ixodid ticks (n=6,336) were collected from 431 Iberian red deer and 142 wild boar in different regions of Spain. We found 10 different ixodid tick species parasitizing Iberian red deer, mainly Hyalomma marginatum marginatum (63.7%), Rhipicephalus (Boophilus) annulatus (7.9%) and R. bursa (7.5%). R. (Boophilus) annulatus was only collected in the province of Cádiz (southern Spain). We found 8 ixodid tick species on the wild boar, mainly Hy. m. marginatum (68.7%), R. bursa (14.6%) and Dermacentor marginatus (9.3%). We found one adult Hy. marginatum rufipes and one adult Hy. anatolicum excavatum parasitizing wild boar from south-central Spain. Mean prevalence of ixodid ticks was 41.3+/-0.08% (n=475) and 31+/-0.09% (n=284) and intensity of parasitization was 13.9+/-0.2 (n=283) and 13.6+/-0.3 (n=130) ticks/animal for Iberian red deer and wild boar, respectively. Only 5 of the 13 ixodid tick species found were shared by Iberian red deer and wild boar. This finding could indicate a host preference when Iberian red deer and wild boar share common habitats. In both Iberian red deer and wild boar from south-central Spain the monthly relative frequencies of Hy. m. marginatum and R. bursa presented an inverse pattern. The highest Hy. m. marginatum relative frequencies coincided with the lowest R. bursa relative frequencies along the year. R. bursa and I. ricinus were present in areas from northern to southern Spain while Hyalomma sp. and D. marginatus were exclusively collected in the two southern thirds of Spain. Haemaphysalis sp. and D. reticulatus were collected in northern Spain. Hy. m. marginatum and R. bursa were present during the whole year in red deer and wild boar from south-central Spain, showing more than one life cycle per year. These results are important for understanding the role of wild ungulates in the maintenance of tick infestations and to improve tick control programmes.

Genes differentially expressed in oropharyngeal tonsils and mandibular lymph nodes of tuberculous and nontuberculous European wild boars naturally exposed to Mycobacterium bovis

Bovine tuberculosis, caused by Mycobacterium bovis (Mycobacterium tuberculosis complex), is a zoonotic disease that affects cattle worldwide. The bacterium infects other animal species, both domesticated and wild, and this range of hosts complicates attempts to control or eradicate the disease. Despite advances in the characterization of the mechanisms involved in host-pathogen interactions and host cell responses to M. tuberculosis complex in human, bovine and mouse cells, differentially expressed genes in tissue biopsies of naturally occurring tuberculous and nontuberculous exposed individuals have been poorly characterized. In this study, differential gene expression was analysed using suppression-subtractive hybridization in oropharyngeal tonsils and mandibular lymph nodes of field-collected tuberculous and nontuberculous European wild boars from a tuberculosis-endemic area of Spain. Real-time PCR and semiquantitative reverse-transcriptase PCR of selected genes confirmed the results of the suppression-subtractive hybridization analysis. Protein expression of selected differentially expressed genes was analysed by radial immunodiffusion or immunohistochemistry. Differential gene expression varied among tuberculous and non-tuberculous groups and between tonsils and lymph nodes. Single and multiple cellular mechanisms were affected, including signal transduction, immune response, inflammation, stress, apoptosis/antiapoptosis, cell structure, adhesion and transport, protein and DNA/RNA metabolism and enzymatic processes. These results demonstrate the modulation of gene expression by mycobacterial infection in tonsils and mandibular lymph nodes of European wild boars naturally exposed to M. bovis, and provide a basis for defining host-pathogen interactions and the mechanism of protective immunity.

Characterization of selected genes upregulated in non-tuberculous European wild boar as possible correlates of resistance to Mycobacterium bovis infection

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (Mycobacterium tuberculosis complex), is a zoonotic disease that affects cattle and wildlife worldwide. These animal hosts can serve as reservoirs of infection, thus increasing the risk of human exposure and infection. In this study we quantified by RNA macroarray fluorescent hybridization and real-time RT-PCR the mRNA levels of genes differentially expressed in oropharyngeal tonsils and mandibular lymph nodes of three and seven individual non-tuberculous and tuberculous wild boars naturally exposed to M. bovis, respectively. These results demonstrated upregulation of two genes, complement component 3 (C3) and methylmalonyl-CoA mutase (MUT), in the non-tuberculous wild boars. These upregulated genes may contribute to resistance of wild boars to bTB by modifying the innate immunity, which limits the ability of the mycobacterium to infect and persist within macrophages. The C3 and MUT genes, therefore, are likely to be good candidates to study as markers of bTB resistance using functional genomics in animal model systems. Identification of genes upregulated in wild animals resistant to bTB contributes to our understanding of the mechanisms of protective immunity and resistance to mycobacterial organisms.

An epidemiological evaluation of Mycobacterium bovis infections in wild game animals of the Spanish Mediterranean ecosystem

Recreational hunting of indigenous wild artiodactyls has been one of the most lucrative and rapidly growing industries in Western Spain over the last five years. In the absence of careful ecological management, one consequence of the commercial exploitation of this natural resource has been the appearance of outbreaks of infectious disease; most notably bovine tuberculosis. From the outset of the study in 1997, we have observed a steady increase in prevalence of Mycobacterium bovis (M. bovis) in both species reaching 1.74 (+/-0.17) in deer in 2002 and 2.32 (+/-0.24) in wild boar. The latter species seems to be most severely affected with pulmonary lesions appearing more chronic than those observed in deer. In this study, we describe the epidemiology of M. bovis in European wild boar (Sus scrofa) and Iberian red deer (Cervus elaphus hispanicus) in Extremadura (W. Spain); a region where there are large areas of natural habitat for these species.

Seroprevalence of six reproductive pathogens in European wild boar (Sus scrofa) from Spain: The effect on wild boar female reproductive performance

We studied the seroprevalence of six reproductive pathogens in Spanish hunter-harvested wild boar females. The sample was representative of the hunting harvest in the studied hunting estates. Mean antibody prevalences were: 60.6+/-0.06% for Aujeszky's disease virus (ADV), 56.6+/-0.09% for porcine parvovirus (PPV), 51.8+/-0.06% for porcine circovirus type 2 (PCV2), 29.7+/-0.09% for Brucella spp. and 36.3+/-0.1% for Toxoplasma gondii. We did not detect antibodies against porcine reproductive and respiratory syndrome virus (PRRSv). ADV seroprevalence was associated with PPV and PCV2 seroprevalence in Spanish wild boar females. Ovulation rate in the studied wild boar females was 4.41+/-0.16 (n=120), mean litter size was 3.91+/-0.16 (n=82) and the partial resorption index 0.92+/-0.17 (n=66). Ovulation rate and litter size were statistically associated with age. T. gondii seroprevalence was negatively related to ovulation rate and partial resorption index. Wild boars from managed fenced estates had antibodies against more pathogens than wild boars from open estates. Potential relations between management of wild boar populations and exposure of individuals to different reproductive pathogens are discussed.

Prevalence of Toxoplasma gondii antibodies in red deer (Cervus elaphus) and other wild ruminants from Spain

Serum samples from 441 red deer (Cervus elaphus) and 161 other wild ruminant species, collected between 1993 and 2005 from six regions of Spain were tested for antibodies against Toxoplasma gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT 1:25 or higher) were detected in 15.6% of red deer. Statistically significant differences were observed among sampling sites with seroprevalence in red deer from Catalonia (42.2%) being significantly higher compared with other Spanish regions (8.7%) (P < 0.05). Statistically significant differences were not observed between T. gondii seroprevalence and sex, age or management of hunting estates (open versus fenced). Seroprevalence of T.gondii infection in other ruminants species was 24% of 79 fallow deer (Dama dama), 21.8% of 33 in roe deer (Capreolus capreolus), 33.3% of three Spanish ibex (Capra pyrenaica), 20% of 10 chamois (Rupicapra pyrenaica), 10% of 10 barbary sheep (Ammotragus lervia), and 14.8% of 27 mouflon (Ovis ammon) in areas not including Catalonia, where no samples from these species were available. Serological results indicated a widespread exposure to T. gondii among wildlife in Spain and suggest that consumption of raw or inadequately cooked meat, as well as handling carcasses of wild game, should be taken into account as a source of infection for humans.

Molecular epidemiology of bovine tuberculosis in wild animals in Spain: A first approach to risk factor analysis

In human tuberculosis (Mycobacterium tuberculosis), molecular epidemiology has accurately indicated the risk factors involved in active transmission of the disease, by comparing individuals whose isolates belong to a cluster with patients whose strains are considered unique. Nevertheless, this application has not been used in bovine tuberculosis (Mycobacterium bovis). Our study describes the integration of epidemiological data into molecular classification data on M. bovis isolates. These were isolated from wild ungulates in Extremadura (western Spain) with the objective of detecting the risk factors linked to the association of strains in clades, which are indicators of the active spread of the disease. The molecular markers used were spoligotyping + VNTR typing (loci: VNTR 2165, VNTR 2461, VNTR 0577, VNTR 0580, VNTR 3192 VNTR 2163a and VNTR 2163b) on a population of 59 M. bovis strains isolated from deer (Cervus elaphus), 112 from wild boar (Sus scrofa), six from bovines, 28 from pigs and 2 from goats (n=207). Epidemiological variables included the animal species from which the strain was isolated, pathological condition of the host (incipient lesion, early and late generalisation), date of sampling (during or after the reproductive period) and hunting season. Bivariant analysis was used to establish the risk factors connected to the association of strains and later, the variables were evaluated by means of logistic regression. Molecular typing grouped a total of 131 strains (64.21%) in 28 clusters and 76 isolates shows unique profiles. The association of strains was connected to the appearance of macroscopic lesions during the reproductive period (O.R. 4.80; 95% CI 1.09-22.99, P<0.005), showing a possible higher transmission during the courting period. This happened mainly during the last hunting season analysed (2002-2003, O.R. 3.69; 95% CI 1.27-11.9, P<0.05), clashing with the time of higher prevalence of the disease in wild ungulates. Active spread was not connected to any species in particular, or to any concrete pathological condition.