Transmissibility of Mycobacterium pinnipedii in a murine model.

The causative agent of tuberculosis in pinnipeds is Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex (MTC). The natural hosts are pinnipeds; however, other non-marine mammals, including humans, can also be infected. The transmissibility of a pathogen is related to its virulence. The transmissibility of a M. pinnipedii strain (i.e., 1856) was investigated in a murine model and compared with that of two Mycobacterium bovis strains (i.e., 534 and 04-303) with different reported virulence. Non-inoculated mice (sentinels) were co-housed with intratracheally inoculated mice. Detailed inspection of mice to search for visible tuberculosis lesions in the lungs and spleen was performed, and bacillus viability at 30, 60, and 90 days post-inoculation (dpi) was assayed. A transmissibility of 100% was recorded at 30 dpi in sentinel mice co-housed with the inoculated mice from the M. pinnipedii and M. bovis 04-303 groups, as evidenced by the recovery of viable M. pinnipedii and M. bovis from the lungs of sentinel mice. Mice inoculated with M. pinnipedii (1856) and M. bovis (534) survived until euthanized, whereas five of the M. bovis 04-303-inoculated mice died at 17 dpi. This study constitutes the first report of the transmissibility of a M. pinnipedii strain in mice and confirms the utility of this experimental model to study virulence features such as the transmission of poorly characterized MTC species.

Negative Regulation of Autophagy during Macrophage Infection by Mycobacterium bovis BCG via Protein Kinase C Activation.

Mycobacterium tuberculosis (Mtb) employs various strategies to manipulate the host's cellular machinery, overriding critical molecular mechanisms such as phagosome-lysosome fusion, which are crucial for its destruction. The Protein Kinase C (PKC) signaling pathways play a key role in regulating phagocytosis. Recent research in Interferon-activated macrophages has unveiled that PKC phosphorylates Coronin-1, leading to a shift from phagocytosis to micropinocytosis, ultimately resulting in Mtb destruction. Therefore, this study aims to identify additional PKC targets that may facilitate Mycobacterium bovis (M. bovis) infection in macrophages. Protein extracts were obtained from THP-1 cells, both unstimulated and mycobacterial-stimulated, in the presence or absence of a general PKC inhibitor. We conducted an enrichment of phosphorylated peptides, followed by their identification through mass spectrometry (LC-MS/MS). Our analysis revealed 736 phosphorylated proteins, among which 153 exhibited alterations in their phosphorylation profiles in response to infection in a PKC-dependent manner. Among these 153 proteins, 55 are involved in various cellular processes, including endocytosis, vesicular traffic, autophagy, and programmed cell death. Importantly, our findings suggest that PKC may negatively regulate autophagy by phosphorylating proteins within the mTORC1 pathway (mTOR2/PKC/Raf-1/Tsc2/Raptor/Sequestosome-1) in response to M. bovis BCG infection, thereby promoting macrophage infection.

Specific identification of Mycobacterium bovis by Loop-Mediated Isothermal Amplification (LAMP) targeting the Region of Difference 12 (RD12) of the M. tuberculosis complex.

Bovine tuberculosis is a prevalent zoonotic disease that causes high risks for production animals, dairy producers and consumers, together with significant economic losses. Thus, methods for easy, fast and specific detection of Mycobacterium bovis in small and medium-sized livestock under field conditions are very required. In this work, a Loop-Mediated Isothermal Amplification LAMP-PCR targeting the Region of Difference 12 (RD12) of M. bovis genome was designed for the purpose of identification. A set of six primers designed for the isothermal amplification of five different genomic fragments led to the specific identification of M. bovis from other mycobacterial species. A basic colorimetric reaction was clearly observed at first sight under natural light, indicating positive identification of M. bovis in a maximum of 30 min of isothermal amplification at 65 °C. The limit of detection was near 50 fg of M. bovis genomic DNA, corresponding approximately to 10 copies of the genome. •The proposed LAMP-PCR amplification of M. bovis genomic DNA might be performed by untrained laboratory personnel.•Specific identification of M. bovis LAMP is possible in 30 min at 65.. C using a simple water bath.•The basic colorimetric reaction for M. bovis identification could be observed with the naked eye under natural light.

Replication and transmission features of two experimental vaccine candidates against bovine tuberculosis subcutaneously administrated in a murine model.

Cattle vaccination is an attractive approach in compliance with control and eradication programs against Bovine Tuberculosis (bTB). Today, there is no anti bTB vaccine licensed. Two vaccine candidates, MbΔmce2 and MbΔmce2-phoP previously designed were evaluated in BALB/c mice, including the parental M. bovis NCTC10772 and a M. bovis hypervirulent Mb04-303 strains as controls. Sentinel mice (non-inoculated) cohoused with subcutaneous inoculated mice. Persistence, visible tuberculosis lesions (VTL) in lungs and spleens and bacillary load were investigated subcutaneously delivered at 60 and 90 days after inoculation (dpi) as well as their potential transmission to naïve mice. While a 100% survival was observed at 90 dpi without VTL in all groups, transmission was not evidenced in the sentinels mice. Vaccine candidates and control strains were isolated from the spleen of all inoculated mice, while Mb04-303 was isolated from the lungs of one inoculated mouse. Vaccine candidate's attenuation considering survival, lung bacillary load and VTL was confirmed, administrated by the subcutaneous route. Future experiments are necessary to demonstrate whether the persistence of both mutants in the spleen, with low CFU, remains over time to increase the potential increasing risk of dissemination to organs and subsequent transmission to other animals by airborne or other routes.

Whole Genome Sequencing Links Mycobacterium bovis From Cattle, Cheese and Humans in Baja California, Mexico.

Mycobacterium bovis causes tuberculosis (TB) in cattle, which in turn can transmit the pathogen to humans. Tuberculosis in dairy cattle is of particular concern where the consumption of raw milk and dairy products is customary. Baja California (BCA), Mexico, presents high prevalence of TB in both cattle and humans, making it important to investigate the molecular epidemiology of the disease in the region. A long-term study was undertaken to fully characterize the diversity of M. bovis genotypes circulating in dairy cattle, cheese and humans in BCA by whole-genome sequencing (WGS). During a 2-year period, 412 granulomatous tissue samples were collected from local abattoirs and 314 cheese samples were purchased from local stores and vendors in BCA and sent to the laboratory for mycobacterial culture, histology, direct PCR and WGS. For tissue samples M. bovis was recovered from 86.8%, direct PCR detected 90% and histology confirmed 85.9% as mycobacteriosis-compatible. For cheese, M. bovis was recovered from 2.5% and direct PCR detected 6% of the samples. There was good agreement between diagnostic tests. Subsequently, a total of 345 whole-genome SNP sequences were obtained. Phylogenetic analysis grouped these isolates into 10 major clades. SNP analysis revealed putative transmission clusters where the pairwise SNP distance between isolates from different dairies was ≤3 SNP. Also, human and/or cheese isolates were within 8.45 (range 0-17) and 5.8 SNP (range 0-15), respectively, from cattle isolates. Finally, a comparison between the genotypes obtained in this study and those reported previously suggests that the genetic diversity of M. bovis in BCA is well-characterized, and can be used to determine if BCA is the likely source of M. bovis in humans and cattle in routine epidemiologic investigations and future studies. In conclusion, WGS provided evidence of ongoing local transmission of M. bovis among the dairies in this high-TB burden region of BCA, as well as show close relationships between isolates recovered from humans, cheese, and cattle. This confirms the need for a coordinated One Health approach in addressing the elimination of TB in animals and humans. Overall, the study contributes to the knowledge of the molecular epidemiology of M. bovis in BCA, providing insight into the pathogen's dynamics in a high prevalence setting.

Phosphate starvation enhances phagocytosis of Mycobacterium bovis/BCG by macrophages.

BACKGROUND: Tuberculosis is an important health problem worldwide. The only available vaccine is M. bovis/BCG, an attenuated mycobacterium that activates the innate and the acquired immune system after being phagocytosed by macrophages and dendritic cells. Vaccination fails to prevent adult pulmonary tuberculosis although it may have a protective effect in childhood infection. Understanding how BCG interacts with macrophages and other immunocompetent cells is crucial to develop new vaccines. RESULTS: In this study we showed that macrophages phagocytose M. bovis/BCG bacilli with higher efficiency when they are cultured without phosphate. We isolated mycobacterial membranes to search for mycobacterial molecules that could be involved in these processes; by immunoblot, it was found that the plasma membranes of phosphate-deprived bacilli express the adhesins PstS-1, LpqH, LprG, and the APA antigen. These proteins are not detected in membranes of bacilli grown with usual amounts of phosphate. CONCLUSIONS: The interest of our observations is to show that under the metabolic stress implied in phosphate deprivation, mycobacteria respond upregulating adhesins that could improve their capacity to infect macrophages. These observations are relevant to understand how M. bovis/BCG induces protective immunity.

Rab7 controls lipid droplet-phagosome association during mycobacterial infection.

Lipid droplets (LDs) are organelles that have multiple roles in inflammatory and infectious diseases. LD act as essential platforms for immunometabolic regulation, including as sites for lipid storage and metabolism, inflammatory lipid mediator production, and signaling pathway compartmentalization. Accumulating evidence indicates that intracellular pathogens may exploit host LDs as source of nutrients and as part of their strategy to promote immune evasion. Notably, numerous studies have demonstrated the interaction between LDs and pathogen-containing phagosomes. However, the mechanism involved in this phenomenon remains elusive. Here, we observed LDs and PLIN2 surrounding M. bovis BCG-containing phagosomes, which included observations of a bacillus cell surrounded by lipid content inside a phagosome and LAM from mycobacteria co-localizing with LDs; these results were suggestive of exchange of contents between these compartments. By using beads coated with M.tb lipids, we demonstrated that LD-phagosome associations are regulated through the mycobacterial cell wall components LAM and PIM. In addition, we demonstrated that Rab7 and RILP, but not Rab5, localizes to LDs of infected macrophages and observed the presence of Rab7 at the site of interaction with an infected phagosome. Moreover, treatment of macrophages with the Rab7 inhibitor CID1067700 significantly inhibited the association between LDs and LAM-coated beads. Altogether, our data demonstrate that LD-phagosome interactions are controlled by mycobacterial cell wall components and Rab7, which enables the exchange of contents between LDs and phagosomes and may represent a fundamental aspect of bacterial pathogenesis and immune evasion.

Analysis of Bovine Tuberculosis Transmission in Jalisco, Mexico through Whole-genome Sequencing.

INTRODUCTION: Bovine tuberculosis, caused by M. bovis, is endemic in Mexico and has had a big impact on public health. Jalisco is considered to be an important dairy region in the country, accounting for approximately 19% of the total milk production. Within Jalisco, the region of Altos Sur holds the largest proportion of the cattle inventory of the state. MATERIAL AND METHODS: To determine the frequency of bovine tuberculosis in Altos Sur, Jalisco, as well as M. bovis genetic diversity, sampling of tissue (lymph nodes, lungs, and liver) from Holstein cattle was performed in four abattoirs belonging to three municipalities of this region (Tepatitlán de Morelos, San Miguel el Alto, and Arandas). Spoligotyping and whole-genome sequencing were carried out to assess the genetic relationships of M. bovis strains circulating in this area, as well as a comparison to isolates from other places in Mexico. RESULTS: Prevalence was 15.06%, and distribution similar among the three municipalities. The most frequent spoligotypes were SB0673, SB121, and SB0145. Whole-genome sequencing revealed three main clades (I, II, III), but isolates did not show clustering by region. CONCLUSION: Phylogenetic analysis suggested ongoing transmission between herds of the different regions, and no unique source of infection was determined. This hinders efforts under the national program for the control and eradication of the disease, so serious attention must be paid to rural regions such as Altos Sur in order to improve its success.

More insights about the interfering effect of Mycobacterium avium subsp. paratuberculosis (MAP) infection on Mycobacterium bovis (M. bovis) detection in dairy cattle.

The estimated herd and within herd Mycobacterium bovis (M. bovis) infection prevalence in the southern Chile regions are 0.3 and 0.67%, respectively. However, higher rates of infection still remain in some herds. In parallel, it is well established that a big proportion of cattle herds are infected with Mycobacterium avium subsp. paratuberculosis (MAP), which has been also associated with a clear interference effect on M. bovis diagnosis. The present study aims to provide more insights about the diagnostic interference for Mycobacterium bovis detection due to co-infection with MAP. To better understand the dynamics of this identified interference, the effect of MAP genotype present, as well as MAP faecal shedding values (as proxy of the infection progression), for each of the CFT results was compared. No relationship was observed between MAP genotype with any type of differential response to the diagnostic tests of M. bovis infection. However, MAP shedding values in animals with positive CFT diagnostic results for M. bovis infection was significantly lower than animals with a negative CFT result, observing that as the MAP shedding load raises, the response to the bovine tuberculin test tends to be negative. The findings reported in this study allows to interpret that one of the causes of the prolonged elimination of M. bovis infection from some cattle herds may be due in part to the advanced MAP infection status in co-infected individuals affecting the outcome of screening in-vivo diagnostic techniques such as CFT. These false negative animals that show negative results to M. bovis detection tests, may maintain the infection at herd level and spread the pathogen to healthy individuals.

Genetically Related Mycobacterium bovis Strains Displayed Differential Intracellular Growth in Bovine Macrophages.

Molecular typing of bacterial isolates provides a powerful approach for distinguishing Mycobacterium bovis (M. bovis) genotypes. It is known that M. bovis strain virulence plays a role in prevalence and spread of the disease, suggesting that strain virulence and prevailing genotypes are associated. However, it is not well understood whether strain virulence correlates with particular genotypes. In this study, we assessed the in vitro intracellular growth of 18 M. bovis isolates in bovine macrophages as an indicator of bacterial virulence and sought a relationship with the genotype identified by spoligotyping. We found 14 different spoligotypes-11 were already known and three spoligotypes had never been reported before. We identified 2 clusters that were phylogenetically related, containing 10 and 6 strains, respectively, and 2 orphan strains. Intracellular growth and phagocytic rates of 18 M. bovis strains were heterogeneous. Our results suggest that M. bovis intracellular growth and phagocytosis are independent of the bacterial lineage identified by spoligotyping.

Rapid culture-based detection of living mycobacteria using microchannel electrical impedance spectroscopy (m-EIS).

BACKGROUND: Multiple techniques exist for detecting Mycobacteria, each having its own advantages and drawbacks. Among them, automated culture-based systems like the BACTEC-MGIT™ are popular because they are inexpensive, reliable and highly accurate. However, they have a relatively long "time-to-detection" (TTD). Hence, a method that retains the reliability and low-cost of the MGIT system, while reducing TTD would be highly desirable. METHODS: Living bacterial cells possess a membrane potential, on account of which they store charge when subjected to an AC-field. This charge storage (bulk capacitance) can be estimated using impedance measurements at multiple frequencies. An increase in the number of living cells during culture is reflected in an increase in bulk capacitance, and this forms the basis of our detection. M. bovis BCG and M. smegmatis suspensions with differing initial loads are cultured in MGIT media supplemented with OADC and Middlebrook 7H9 media respectively, electrical "scans" taken at regular intervals and the bulk capacitance estimated from the scans. Bulk capacitance estimates at later time-points are statistically compared to the suspension's baseline value. A statistically significant increase is assumed to indicate the presence of proliferating mycobacteria. RESULTS: Our TTDs were 60 and 36 h for M. bovis BCG and 20 and 9 h for M. smegmatis with initial loads of 1000 CFU/ml and 100,000 CFU/ml respectively. The corresponding TTDs for the commercial BACTEC MGIT 960 system were 131 and 84.6 h for M. bovis BCG and 41.7 and 12 h for M smegmatis, respectively. CONCLUSION: Our culture-based detection method using multi-frequency impedance measurements is capable of detecting mycobacteria faster than current commercial systems.

Rapid culture-based detection of living mycobacteria using microchannel electrical impedance spectroscopy (m-EIS)

BACKGROUND: Multiple techniques exist for detecting Mycobacteria, each having its own advantages and drawbacks. Among them, automated culture-based systems like the BACTEC-MGIT™ are popular because they are inexpensive, reliable and highly accurate. However, they have a relatively long "time-to-detection" (TTD). Hence, a method that retains the reliability and low-cost of the MGIT system, while reducing TTD would be highly desirable. METHODS: Living bacterial cells possess a membrane potential, on account of which they store charge when subjected to an AC-field. This charge storage (bulk capacitance) can be estimated using impedance measurements at multiple frequencies. An increase in the number of living cells during culture is reflected in an increase in bulk capacitance, and this forms the basis of our detection. M. bovis BCG and M. smegmatis suspensions with differing initial loads are cultured in MGIT media supplemented with OADC and Middlebrook 7H9 media respectively, electrical "scans" taken at regular intervals and the bulk capacitance estimated from the scans. Bulk capacitance estimates at later time-points are statistically compared to the suspension's baseline value. A statistically significant increase is assumed to indicate the presence of proliferating mycobacteria. RESULTS: Our TTDs were 60 and 36 h for M. bovis BCG and 20 and 9 h for M. smegmatis with initial loads of 1000 CFU/ml and 100,000 CFU/ml respectively. The corresponding TTDs for the commercial BACTEC MGIT 960 system were 131 and 84.6 h for M. bovis BCG and 41.7 and 12 h for M smegmatis, respectively. CONCLUSION: Our culture-based detection method using multi-frequency impedance measurements is capable of detecting mycobacteria faster than current commercial systems.

Detecção de Mycobacterium bovis por reação em cadeia de polimerase no leite de vacas reagentes ao teste de tuberculinização no estado de Alagoas / Mycobacterium bovis for detection of reaction polymerase chain in cows milk to reagents tuberculin test in Alagoas state

A tuberculose é uma afecção de caráter infectocontagiosa de ocorrência global responsável por grandes prejuízos à pecuária leiteria. Devido à importância da doença para a saúde animal e humano, objetivou-se detectar por Reação em Cadeia de Polimerase M. bovis reagentes no leite de vacas reagentes no teste de tuberculinização. O estudo foi desenvolvido em rebanhos leiteiros localizados em municípios da bacia leiteira do estado de Alagoas. Utilizou-se 130 fêmeas da espécie bovina com idades e raças variadas, em diferentes períodos de lactação. Nessas fêmeas foi realizado o teste de tuberculinização cervical comparativo. Após a realização dos testes, observou-se a frequência de 5,38% (7/130) para tuberculose bovina na região. O município diagnosticado com maior frequência de animais reagentes foi Batalha com 57,14% (4/7), seguido de Monteirópolis, Jaramataia e Jacaré dos Homens, todos com 14,28 %.(1/7) de fêmeas positivas onde identificou-se 66,67% de focos de infecção para tuberculose bovina na região. O DNA foi extraído de sete amostras de leite dos animais reagentes a tuberculinização para realização da PCR, todas as amostras foram positivas na PCR específica para M. bovis. A presença do M. bovis no leite de vacas reagentes evidencia o risco da infecção humana através da ingestão de leite cru e seus derivados. Ficando evidente a importância da realização do teste de tuberculinização para a vigilância epidemiológica da tuberculose nos rebanhos de bovinos no estado de Alagoas.(AU)

Tuberculosis is a contagious infectious disease character of global occurrence responsible for major losses to dairy cattle. Because of the importance of the disease to animal and human health, aimed of detect by Polymerase Chain Reaction,at contamination at M. bovis in milk cows in the tuberculin test. The study was conducted in dairy herds located in municipalities in the dairy region of the state of Alagoas. We used 130 female bovine animals aged and varied races, in different periods of lactation. These females was performed comparative cervical tuberculin test. After the tests, the frequency was observed in 5.38% (7/130) for bovine tuberculosis in the region. The municipality diagnosed with greater frequency of positive animals was Battle with 57.14% (4/7), followed by Monteirópolis, Jaramataia and Alligator Men, all with 14.28%. (1/7) of positive females where checking 66.67% of outbreaks of infection for bovine tuberculosis in the region. The DNA was extracted from seven samples of milk from tuberculin animals reagents for the PCR, all samples were positive in the PCR specific for M. bovis. The M. bovis presence in the milk of cows reagents shows the risk of human infection through the ingestion of raw milk and its derivatives. Evidencing the importance of carrying out the tuberculin test for tuberculosis surveillance in cattle herds in the state of Alagoas.(AU)

Detecção de Mycobacterium bovis por reação em cadeia de polimerase no leite de vacas reagentes ao teste de tuberculinização no estado de Alagoas / Mycobacterium bovis for detection of reaction polymerase chain in cows milk to reagents tuberculin test in Alagoas state

A tuberculose é uma afecção de caráter infectocontagiosa de ocorrência global responsável por grandes prejuízos à pecuária leiteria. Devido à importância da doença para a saúde animal e humano, objetivou-se detectar por Reação em Cadeia de Polimerase M. bovis reagentes no leite de vacas reagentes no teste de tuberculinização. O estudo foi desenvolvido em rebanhos leiteiros localizados em municípios da bacia leiteira do estado de Alagoas. Utilizou-se 130 fêmeas da espécie bovina com idades e raças variadas, em diferentes períodos de lactação. Nessas fêmeas foi realizado o teste de tuberculinização cervical comparativo. Após a realização dos testes, observou-se a frequência de 5,38% (7/130) para tuberculose bovina na região. O município diagnosticado com maior frequência de animais reagentes foi Batalha com 57,14% (4/7), seguido de Monteirópolis, Jaramataia e Jacaré dos Homens, todos com 14,28 %.(1/7) de fêmeas positivas onde identificou-se 66,67% de focos de infecção para tuberculose bovina na região. O DNA foi extraído de sete amostras de leite dos animais reagentes a tuberculinização para realização da PCR, todas as amostras foram positivas na PCR específica para M. bovis. A presença do M. bovis no leite de vacas reagentes evidencia o risco da infecção humana através da ingestão de leite cru e seus derivados. Ficando evidente a importância da realização do teste de tuberculinização para a vigilância epidemiológica da tuberculose nos rebanhos de bovinos no estado de Alagoas.

Tuberculosis is a contagious infectious disease character of global occurrence responsible for major losses to dairy cattle. Because of the importance of the disease to animal and human health, aimed of detect by Polymerase Chain Reaction,at contamination at M. bovis in milk cows in the tuberculin test. The study was conducted in dairy herds located in municipalities in the dairy region of the state of Alagoas. We used 130 female bovine animals aged and varied races, in different periods of lactation. These females was performed comparative cervical tuberculin test. After the tests, the frequency was observed in 5.38% (7/130) for bovine tuberculosis in the region. The municipality diagnosed with greater frequency of positive animals was Battle with 57.14% (4/7), followed by Monteirópolis, Jaramataia and Alligator Men, all with 14.28%. (1/7) of positive females where checking 66.67% of outbreaks of infection for bovine tuberculosis in the region. The DNA was extracted from seven samples of milk from tuberculin animals reagents for the PCR, all samples were positive in the PCR specific for M. bovis. The M. bovis presence in the milk of cows reagents shows the risk of human infection through the ingestion of raw milk and its derivatives. Evidencing the importance of carrying out the tuberculin test for tuberculosis surveillance in cattle herds in the state of Alagoas.

Zoonotic tuberculosis. A comprehensive ONE HEALTH approach.

The objective of this report is to provide information on Mycobacterium tuberculosis complex infections in animals and in humans. Included is information on the susceptibility of different species as well as information on etiology, epidemiology, pathogenesis, diagnosis, prevention and control of this disease. The term One Health has been adopted to describe the unified human medical and veterinary interdisciplinary/multidisciplinary collaborative approach to zoonoses and will be critical for future endeavors in the control of the global TB epidemic. This unified paradigm is ideally suited for control of bovine TB and many other international public health and clinical health issues. Sharing resources and increasing interaction between public health and veterinary medical scientists can raise awareness of 'shared risk' of bovine TB between humans and animals and, in resource-limited situations, can maximize use of existing infrastructure and reduce unnecessary duplication of effort in disease control programs.

Zoonotic tuberculosis: A comprehensive one health approach

The objective of this report is to provide information on Mycobacterium tuberculosis complex infections in animals and in humans. Included is information on the susceptibility of different species as well as information on etiology, epidemiology, pathogenesis, diagnosis, prevention and control of this disease. The term One Health has been adopted to describe the unified human medical and veterinary interdisciplinary/multidisciplinary collaborative approach to zoonoses and will be critical for future endeavors in the control of the global TB epidemic. This unified paradigm is ideally suited for control of bovine TB and many other international public health and clinical health issues. Sharing resources and increasing interaction between public health and veterinary medical scientists can raise awareness of ‘shared risk' of bovine TB between humans and animals and, in resource-limited situations, can maximize use of existing infrastructure and reduce unnecessary duplication of effort in disease control programs.

El objetivo de este artículo es proporcionar información sobre las infecciones por el Complejo Mycobacterium tuberculosis en animales y en humanos. Se incluye información sobre la susceptibilidad de diferentes especies, así como sobre la etiología, epidemiología, patogenia, diagnóstico, prevención y control de esta enfermedad. La expresión UNA SALUD ha sido adoptada para describir el enfoque unificado de la medicina humana y la veterinaria, de colaboración interdisciplinaria/multidisciplinaria en las zoonosis, que puede resultar fundamental para el control de la endemia mundial de tuberculosis. Este paradigma unificado es especialmente relevante para el control de la tuberculosis bovina. Compartir recursos y lograr una mayor interacción entre la investigación en salud pública y en medicina veterinaria puede elevar la conciencia de “riesgo compartido” de la tuberculosis bovina en humanos y animales y, en situaciones de recursos limitados, puede maximizar el uso de la infraestructura existente y reducir la duplicación innecesaria de esfuerzos en los programas de control de la infección y enfermedad.

Risk factors for Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium bovis coinfection at individual animal level in southern Chile cattle populations.

Mycobacterium avium subsp. paratuberculosis (MAP) causes a chronic intestinal infection mainly in domestic and wild ruminants and is transmitted primarily by the fecal-oral route. Mycobacterium bovis (M. bovis) produces a chronic infection principally of the respiratory system. It affects most domestic mammals, wild species, and humans and is spread via the respiratory or oral route. It is important to note that M. bovis is considered a major zoonotic agent. The term coinfection refers to the coexistence of two or more infectious agents in the same host. The goal of the present study was to assess management factors that may favor coinfection with MAP and M. bovis in cattle at an individual level. A cross-sectional study was conducted including 366 cattle from 11 herds. Diagnostic information for both pathogens and individual characteristics of the animals and management practices applied on them was collected from each herd. The results indicated a set of variables being more frequent in the coinfected group of animals and mainly related with biosecurity measures. This study provided regionally based data that may be used to design future control plans for both cattle infections in southern Chile.

Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis

The presence of intestinal helminths can down-regulate the immune response required to control mycobacterial infection. BALB/c mice infected with Mycobacterium bovis following an infection with the intestinal helminth Strongyloides venezuelensis showed reduced interleukin-17A production by lung cells and increased bacterial burden. Also, small granulomas and a high accumulation of cells expressing the inhibitory molecule CTLA-4 were observed in the lung. These data suggest that intestinal helminth infection could have a detrimental effect on the control of tuberculosis (TB) and render coinfected individuals more susceptible to the development of TB.

Valoración de las pruebas diagnósticas para tuberculosis bovina en un rebaño bovino ubicado en zona de alta incidencia del estado Zulia Venezuela / Valuation of diagnostic tests for bovine tuberculosis in cattle herd located in a high incidence area of Zulia state Venezuela

Las pruebas de tuberculina son las de uso generalizado para el diagnóstico y el control de la tuberculosis (TBC) en el hombre y en los animales. Se caracteriza por una compleja mezcla de antígenos de mycobacterias capaces de inducir reacciones de hipersensibilidad en animales infectados, incluso con mycobacterias diferentes al Mycobacterium bovis, por efectos de reactividad cruzada. La preparación del derivado protéico purificado (PPD), es similar a la de la tuberculina, a diferencia de la concentración de proteínas, las cuales se separan por precipitación con agentes químicos y no por calor, aumentando su especificidad. Los primeros resultados obtenidos con las pruebas serológicas para el diagnóstico de tuberculosis bovina muestran que existe una gran reactividad antigénica cruzada entre las especies de mycobacterias, por lo que se requiere de antígenos más específicos. Se implementó un ELISA-TBC para la detección de anticuerpos anti M. bovis. El ensayo inmunoenzimático para el IFN-y bovino cuando se utilizó conjuntamente con el sistema de cultivo de sangre completa resultó en un ensayo in vitro rápido y sensible para detectar la reactividad de la inmunidad mediada por células al M. bovis en el ganado infectado. A partir de estas pruebas se compararon los resultados obtenidos para establecer la sensibilidad y especificidad utilizando como prueba oro, los datos obtenidos en el cultivo bacteriológico y la reacción en cadena de la polimerasa (PCR). Los animales reaccionantes a la tuberculina incluyeron animales positivos a PPD-B y PPD-A, así como animales negativos a cultivo bacteriológico y PCR. Los PPD-B positivos, no son en su totalidad, los mismos reaccionantes al IFN-y o al ELISA-TBC. Aún cuando su sensibilidad es baja, muestra mayor especificidad y concordancia que el resto de las pruebas utilizadas.

The tuberculin tests are widely used for diagnosis and control of tuberculosis (TB) in humans and animals. It is characterized by a complex mixture of mycobacteria antigens able to induce hypersensitivity reactions even in animals infected with mycobacteria other than M. bovis, for purposes of cross-reactivity. The preparation of purified protein derivative (PPD) is similar to the tuberculin, unlike the concentration of proteins which are separated by precipitation with chemical agents and not by increasing its specific heat. The first results obtained with the serological tests for diagnosis of bovine tuberculosis show that there is a great antigenic cross-reactivity between mycobacterias species so it requires more specific antigens. It implemented a cattle IFN-g test and ELISA-TBC to detect anti M. bovis activity. The immunoassay test for IFN-g used in conjunction with the cropping system of whole blood resulted in an essay in vitro rapid and sensitive to detect the reactivity of the cell-mediated immunity to M. bovis in livestock infected. Comparative test of the tuberculina, test of Gamma Interferon (INF-y) and a test ELISA-TBC, soon was taken to slaughter house to take linfoides weave samples and nodules, to which the test of chain reaction of Polimerasa was applied to them, to bacteriological culture and (PCR), for the identification from the pathogen. From these tests the patterns of immune response settled down and the obtained results of the different tests were compared to establish sensitivity and specificity using with t gold standard, the data collected in culture and PCR. The results were analyzed using the statistical method of analysis of variance for nonparametric tests. The PPD B-positive, are not the same reacting to IFN-y or at ELISA-TBC. Although its sensitivity is low, it shows greater specificity and consistency as the rest of the tests used.

Management factors associated with bovine tuberculosis on dairy herds in Rio de Janeiro, Brazil

With the purpose of identifying management factors that may be influencing the prevalence of bovine tuberculosis under tropicalconditions, namely in Rio de Janeiro, Brazil, 1632 cows were tested through the single cervical tuberculin test. A questionnairewas completed for each herd. A total of 207 positive reactions were observed, corresponding to 12.7% of the studied cattle. Themain factors observed that may be influencing the prevalence of bovine tuberculosis on those farms were the absence orreduced veterinary assistance and the herd size. The presence of adequate cattle houses and the highly intensive managementare also considered to be likely to influence the prevalence of the disease. Under tropical conditions, a tuberculosis controlprogram, in addition to the test-and-slaughter control method, should include an investigation of herd management practices totry to identify factors that are likely to influence the prevalence of the disease.