Spatial-temporal risk factors in the occurrence of rabies in Mexico.

Rabies is a zoonotic disease that affects livestock worldwide. The distribution of rabies is highly correlated with the distribution of the vampire bat Desmodus rotundus, the main vector of the disease. In this study, climatic, topographic, livestock population, vampire distribution and urban and rural zones were used to estimate the risk for presentation of cases of rabies in Mexico by co- Kriging interpolation. The highest risk for the presentation of cases is in the endemic areas of the disease, i.e. the States of Yucatán, Chiapas, Campeche, Quintana Roo, Tabasco, Veracruz, San Luis Potosí, Nayarit and Baja California Sur. A transition zone for cases was identified across northern Mexico, involving the States of Sonora, Sinaloa, Chihuahua, and Durango. The variables topography, vampire distribution, bovine population and rural zones are the most important to explain the risk of cases in livestock. This study provides robust estimates of risk and spread of rabies based on geostatistical methods. The information presented should be useful for authorities responsible of public and animal health when they plan and establish strategies preventing the spread of rabies into rabies-free regions of México.

Vaccination Strategies in a Potential Use of the Vaccine against Bovine Tuberculosis in Infected Herds.

Bovine tuberculosis (bTB) is a disease of cattle that represents a risk to public health and causes severe economic losses to the livestock industry. Recently, one of the strategies recommended for reducing the prevalence of the disease in animals is the use of the BCG vaccine, alone or in combination with proteins. It has been shown that the vaccine elicits a strong immune response, downsizes the number of animals with visible lesions, and reduces the rate of infection as well as the bacillary count. This paper, based on scientific evidence, makes suggestions about some practical vaccination alternatives that can be used in infected herds to reduce bTB prevalence, considering BCG strains, vaccine doses, routes of application, and age of the animals. Our conclusion is that vaccination is a promising alternative to be included in current control programs in underdeveloped countries to reduce the disease burden.

Descriptive and Time-Series Analysis of Rabies in Different Animal Species in Mexico.

The spatio-temporal epidemiology of rabies has related the influence of environmental factors and anthropogenic changes on the movements of the hematophagous bat Desmodus rotundus. In Mexico, D. rotundus is the main transmitter of the rabies virus for different livestock species, modifying annually the fluctuation of the number of cases of rabies and its dissemination in subtropical areas and regions considered free of the disease. The purpose of this study was to perform a descriptive analysis of the distribution of cases of rabies in Mexico, and to perform a time-series analysis to evaluate stationarity and to predict the number of cases for the following year. A total of 3,469 cases were reported in the period of interest, of which the 89.1% occurred in cattle, 4.3% in horses, 1.5% in sheep, 0.6% in goats, 0.01% in pig, 3.1% in vampire bats, 0.3% in cervids, 0.2% in skunks, 0.1% in insectivorous bats, 0.1% in foxes, 0.1% in buffaloes, and 0.02% in coatis; 0.5% were not identified. The most frequent antigenic variants reported were AgV11, AgV5, and AgV3, associated with D. rotundus. The distribution of cases in bats correlates with the distribution of cases in domestic and wild animals; however, cases were observed in wild species in non-endemic areas of Mexico, like the State of Chihuahua. The additive model used in the time-series analysis showed a seasonal pattern with a peak of cases at the beginning of each year, from January to March. The model showed a good predicting value; the Pearson correlation coefficient R2 was 0.705. The highest probability for the occurrence of rabies cases in the different species estimated by Ordinary Kriging was in the coast of the Gulf of Mexico, involving the states of Tamaulipas, Veracruz, Tabasco, Chiapas, and Yucatan. This study confirms that rabies in domestic and wild species is endemic in tropical and subtropical areas-however, cases have been observed in new geographic areas-and provides useful information to support actions to stop the spread of the rabies virus or the reservoir, and for planning vaccination strategies considering time and place.

Prime Vaccination with Chitosan-Coated Phipps BCG and Boosting with CFP-PLGA against Tuberculosis in a Goat Model.

Attempts to improve the immune response and efficacy of vaccines against tuberculosis in cattle, goats, and other animal species have been the focus of research in this field during the last two decades. Improving the vaccine efficacy is essential prior to running long-lasting and expensive field trials. Studies have shown that vaccine protocols utilizing boosting with proteins improve the vaccine efficacy. The use of polymers such as chitosan and PolyLactic-co-Glycolic Acid (PLGA) improves the immune response against different diseases by improving the interaction of antigens with the cellular immune system and modulating the host immune response. This study shows that the prime BCG vaccination, boosted with a culture filtrate protein (CFP), alone or in combination with chitosan and PolyLactic-co-Glycolic Acid (PLGA), have the potential to reduce tuberculosis (TB) dissemination by reducing the number of animals with lesions, the number of lesions per animal, and the size of the lesions in vaccinated animals, compared with those not vaccinated or those vaccinated with BCG alone. The vaccinated groups showed significantly higher Interferon-γ levels in the blood compared to the control, nonvaccinated group after vaccination, after boosting, and after the challenge with the wild-type Mycobacterium bovis strain.

Application of antigenic biomarkers for Mycobacterium tuberculosis.

The study and characterization of biomolecules involved in the interaction between mycobacteria and their hosts are crucial to determine their roles in the invasion process and provide basic knowledge about the biology and pathogenesis of disease. Promising new biomarkers for diagnosis and immunotherapy have emerged recently. Mycobacterium is an ancient pathogen that has developed complex strategies for its persistence in the host and environment, likely based on the complexity of the network of interactions between the molecules involved in infection. Several biomarkers have received recent attention in the process of developing rapid and reliable detection techniques for tuberculosis. Among the most widely investigated antigens are CFP-10 (10-kDa culture filtrate protein), ESAT-6 (6-kDa early secretory antigenic target), Ag85A, Ag85B, CFP-7, and PPE18. Some of these antigens have been proposed as biomarkers to assess the key elements of the response to infection of both the pathogen and host. The design of novel and accurate diagnostic methods is essential for the control of tuberculosis worldwide. Presently, the diagnostic methods are based on the identification of molecules in the humoral response in infected individuals. Therefore, these tests depend on the capacity of the host to develop an immune response, which usually is heterogeneous. In the last 20 years, special attention has been given to the design of multiantigenic diagnostic methods to improve the levels of sensitivity and specificity. In this review, we summarize the state of the art in the study and use of mycobacterium biomolecules with the potential to support novel tuberculosis control strategies.

Effect and Analysis of Bacterial Lysates for the Treatment of Recurrent Urinary Tract Infections in Adults.

Urinary tract infection (UTI) is a relevant public health problem, economically and socially affecting the lives of patients. The increase of antimicrobial bacterial resistance significantly hinders the treatment of UTIs, raising the need to search for alternative therapies. Bacterial lysates (BL) obtained from Escherichia coli and other pathogens have been used to treat different infectious diseases with promising results. This work aims to evaluate the effect and composition of an autologous BL for the treatment and control of recurrent UTIs in adults. The results show remission in 70% of the patients within the first three months after the administration of BL, while the infection is maintained under control for 6-12 months. The analysis by liquid chromatography-mass spectrometry (LC-MS) of the BL fractions recognized by the sera of patients shows the presence of cytosolic proteins, fimbriae, OMPs, and LPS. Our study demonstrates that the autologous BL contributed to the treatment and control of recurrent UTIs in adults, and its composition shows that different surface components of E. coli are potential immunogens that could be used to create a polyvalent protective vaccine.

Spatiotemporal analysis of rabies in cattle in central Mexico.

Spatial epidemiology of bat-transmitted rabies in cattle has been limited to spatial distribution of cases, an approach that does not identify hidden patterns and the spread resulting in outbreaks in endemic and susceptible areas. Therefore, the purpose of this study was to determine the relationship between the three variables average annual maximum, annual minimum temperature and precipitation in the region on the one hand, and the spatial distribution of cases on the other, using geographic information systems and co-Kriging considering that these environmental variables condition the existence of the rabies vector Desmodus rotundus. A stationary behaviour between the primary and the secondary variables was verified by basic statistics and moving window statistics. The directions of greater and lesser spatial continuity were determined by experimental cross-semivariograms. It was found that the highest risk for bovine paralytic rabies occurs in areas known as La Huasteca Potosina and La Sierra Gorda that are characterized by a maximum temperature of 29.5 °C, a minimum temperature of 16.5 °C and precipitation of 1200 mm. A risk estimation map was obtained for the presence of rabies with a determination coefficient greater than 95%, and a correlation coefficient greater than 0.95. Our conclusion is that ordinary co- Kriging provides a better estimation of risk and spatial distribution of rabies than simple Kriging, making this the method recommended for risk estimation and regional distribution of rabies.

Genome-Wide Association Study in Mexican Holstein Cattle Reveals Novel Quantitative Trait Loci Regions and Confirms Mapped Loci for Resistance to Bovine Tuberculosis.

Bovine tuberculosis (bTB) is a disease of cattle that represents a risk to public health and causes severe economic losses to the livestock industry. Recently, genetic studies, like genome-wide association studies (GWAS) have greatly improved the investigation of complex diseases identifying thousands of disease-associated genomic variants. Here, we present evidence of genetic variants associated with resistance to TB in Mexican dairy cattle using a case-control approach with a selective DNA pooling experimental design. A total of 154 QTLRs (quantitative trait loci regions) at 10% PFP (proportion of false positives), 42 at 5% PFP and 5 at 1% PFP have been identified, which harbored 172 annotated genes. On BTA13, five new QTLRs were identified in the MACROD2 and KIF16B genes, supporting their involvement in resistance to bTB. Six QTLRs harbor seven annotated genes that have been previously reported as involved in immune response against Mycobacterium spp: BTA (Bos taurus autosome) 1 (CD80), BTA3 (CTSS), BTA 3 (FCGR1A), BTA 23 (HFE), BTA 25 (IL21R), and BTA 29 (ANO9 and SIGIRR). We identified novel QTLRs harboring genes involved in Mycobacterium spp. immune response. This is a first screening for resistance to TB infection on Mexican dairy cattle based on a dense SNP (Single Nucleotide Polymorphism) chip.

Prevalence and Zoonotic Potential of Giardia intestinalis in Dogs of the Central Region of Mexico.

Giardia intestinalis is a protozoan of worldwide distribution capable of infecting a large number of species, including humans and domestic animals. Dogs represent a risk to public health due to cross-infections by the zoonotic assemblages. However, there is little information concerning the prevalence and frequency of this parasite and its assemblages in dogs of the central region of Mexico, thus this study aimed to contribute to this matter. A total of 402 feces samples from dogs of different settings (shelter, breeding establishments, domestic and stray) were obtained and direct coproparasitoscopic examination by flotation revealed a prevalence of 25%. PCR was performed for amplification of the ß-Giardin gene, to which 24 samples were positive. Assemblages were obtained through RFLP analysis, using enzymes Hae III to obtain the main genotypes (A-G), and Hha I to subtype assemblage A. All 24 samples were genotyped as assemblage A, with 83% as AI and 17% as AII. Thus, these findings confirm that dogs in the central region of Mexico are a risk for zoonotic transmission of this parasite, emphasizing the importance of a much needed control of the disease in this species.

Molecular epidemiology of cattle tuberculosis in Mexico through whole-genome sequencing and spoligotyping.

Mycobacterium bovis infection in cattle persists in Mexico, posing a threat to human health. Control of bovine tuberculosis, through the National Program Against Bovine Tuberculosis, has led to the decrease of disease prevalence in most of the country, except for high dairy production regions. Genotyping of M. bovis has been performed mainly by spoligotyping and variable number tandem repeats (VNTR), but higher resolution power can be useful for a finer definition of the spread of the disease. Whole genome sequencing and spoligotyping was performed for a set of 322 M. bovis isolates from different sources in Mexico: Baja California, Coahuila, Estado de Mexico, Guanajuato, Hidalgo, Jalisco, Queretaro and Veracruz, from dairy and beef cattle, as well as humans. Twelve main genetic clades were obtained through WGS and genetic diversity analysis. A clear differentiation of the Baja California isolates was seen as they clustered together exclusively. However, isolates from the central states showed no specific clustering whatsoever. Although WGS proves to have higher resolving power than spoligotyping, and since there was concordance between WGS and spoligotyping results, we consider that the latter is still an efficient and practical method for monitoring bovine tuberculosis in developing countries, where resources for higher technology are scarce.

Genetic diversity based on MIRU-VNTR profile of isolates of Mycobacterium bovis from Mexican cattle.

Bovine tuberculosis (bTB) is a disease caused by Mycobacterium bovis (M. bovis), which affects cattle, animal species and humans. To determinate the genetic structure of strains of M. bovis in mexican cattle, 467 isolates obtained from 2009 to 2010 from different regions of Mexico with known spoligotype were included in the study. The isolates were genotyped by interspersed repeated mycobacterial units-variable number tandem repeats (MIRU-VNTR) obtaining 13 MIRU-VNTR groups. When combining MIRU-VNTR patterns with its spolygotypes, the Hunter genetic discrimination index (HGDI), we obtained 421 genetic patterns distributed in 17 groups. The HGDI for the total loci was 0.99. The locus that presented the higher HGDI was 2461 (0.857), while the locus with the lowest HGDI was 2686 (0.239). When we analyzed our results, using just 6 or 8 MIRU-VNTR we obtained an discriminatory power of 0.8499 and 0.8875 respectively indicating lower HGDI than 12 MIRU-VNTR locus.

Molecular Relationship between Strains of M. bovis from Mexico and Those from Countries with Free Trade of Cattle with Mexico.

The purpose of this study was to identify relationships between spoligotypes of M. bovis from cattle in Mexico and those reported in countries with free trade of cattle with Mexico: Australia, Canada, New Zealand and the United States of America. Mexican spoligotypes were obtained from isolates collected from cattle in different parts of the country. Spoligotypes from Canada and New Zealand were obtained from different reports in the literature. Those from the United States were obtained from the database of the National Veterinary Services Laboratory in APHIS-USDA. In order to perform the analysis in a single data set, spoligotypes were all converted to binary data and classified according to www.mbovis.org or www.pasteur-guadeloupe.fr:8081. Epidemiologic information included country and species infected. From 3,198 isolates, 174 different spoligotypes were obtained, 95 were orphans. Ninety one percent of the isolates came from the Unites States (n = 1,609) and Mexico (n = 1,323). Spoligotype SB0265 is shared between Canada and the United States in cattle and wildlife. Six spoligotypes, SB0673, SB0121, SB0145, SB0971, SB0140 and SB1165, were frequent in cattle and wildlife in the United States and cattle in Mexico, suggesting wide exchange of strains. Spoligotype SB0669 was found only in Mexico. Spoligotype SB0140 was the most common in Australia and the sixth in the United States and Mexico. In a phylogenetic analysis, spoligotype SB0140 appears as the oldest spoligotype in the data set, suggesting this as the ancestral spoligotype for all spoligotypes in the five countries. Some spoligotypes are shared by animals and humans, corroborating the zoonotic importance of M. bovis.

Comportamiento epidemiológico de la rabia paralítica bovina en la región central de México, 2001-2013 / Epidemiological trends in bovine paralytic rabies in central Mexico, 2001-2013

OBJETIVO:Determinar la distribución geoespacial de los casos de rabia paralítica bovina transmitida por Desmodus rotundus en los estados de Guanajuato, Querétaro y San Luis Potosí, México. MÉTODOS: Estudio epidemiológico transversal a partir de los casos notificados por las campañas estatales de control de la rabia paralítica bovina en Guanajuato (2008-2013), Querétaro (2005-2013) y San Luis Potosí (2001-2013). Se confirmaron los casos por inmunofluorescencia directa. Se elaboraron mapas de distribución de los casos por año y por especie, mediante el software ArcMap versión 10.1. Para identificar áreas con condiciones apropiadas para la presencia de casos se combinaron las variables bioclimáticas con los casos georreferenciados, mediante el programa MaxEnt versión 3.3.3. RESULTADOS: Se registraron 1 037 casos, de los cuales, 911 (87,9%) ocurrieron en San Luis Potosí, 82 (7,9%) en Querétaro y 44 (4,2%) en Guanajuato. Del total, 87,4% ocurrió en alturas menores de 1 500 msnm. En Guanajuato y Querétaro, 77,3% y 42,3% de los casos, respectivamente, ocurrieron en alturas mayores de 1 500 msnm. Los meses de mayor incidencia fueron de diciembre a marzo. La variante antigénica viral V11 fue la más frecuente (173 casos), presente en los tres estados estudiados. En el canal endémico, el promedio de casos se mantiene en la zona de seguridad de enero a marzo, pero de abril a junio excede la mediana. La distribución espacial de los casos muestra la diseminación reciente de la enfermedad, lo que coincide con la presencia del murciélago vampiro. CONCLUSIONES: La rabia paralítica bovina se ha extendido a regiones anteriormente libres de esta enfermedad. Las características ambientales y la altura sobre el nivel del mar no limitan la presentación de casos. Se debe mantener un monitoreo constante para la detección oportuna de casos. La vacunación se debe realizar antes del comienzo de las lluvias, sin esperar la aparición de brotes.

OBJECTIVE: To determine the geospatial distribution of bovine paralytic rabies cases transmitted by Desmodus rotundus in the Mexican states of Guanajuato, Querétaro, and San Luis Potosí. METHODS: This was a cross-sectional epidemiological study based on cases reported during statewide campaigns for the control of bovine paralytic rabies in Guanajuato (2008-2013), Querétaro (2005-2013) and San Luis Potosí (2001-2013). All cases were confirmed by direct immunofluorescence. Maps showing the distribution of cases by year and species were constructed using ArcMap version 10.1. To identify areas where conditions favor the appearance of cases, bioclimatic variables were combined with georeferenced cases using MaxEnt version 3.3.3. RESULTS: Of the 1037 cases recorded, 911 (87.9%) occurred in San Luis Potosí, 82 (7.9%) in Querétaro, and 44 (4.2%) in Guanajuato. Of the total number of cases, 87.4% occurred at altitudes of less than 1500 meters above sea level. In Guanajuato and Querétaro, 77.3% and 42.3% of the cases, respectively, occurred at altitudes greater than 1 500 meters above sea level. Peak incidence was recorded from December to March. The V11 antigenic variant of the virus was the most common (173 cases); it was found in all three states. In the endemic channel, the average number of cases remains within the security zone from January to March but exceeds the median value from April to June. The spatial distribution of cases shows that the disease has spread recently, which correlates with the presence of the vampire bat. CONCLUSIONS: Bovine paralytic rabies has spread to areas that were formerly free of the disease. Environmental characteristics and the altitude above sea level do not limit the appearance of cases. Constant monitoring should be conducted for early case detection. Vaccination should take place before the rainy season starts, without waiting for outbreaks to occur.

Comportamiento epidemiológico de la rabia paralítica bovina en la región central de México, 2001–2013 / Epidemiological trends in bovine paralytic rabies in central Mexico, 2001–2013

Objetivo. Determinar la distribución geoespacial de los casos de rabia paralítica bovina transmitida por Desmodus rotundus en los estados de Guanajuato, Querétaro y San Luis Potosí, México. Métodos. Estudio epidemiológico transversal a partir de los casos notificados por las campañas estatales de control de la rabia paralítica bovina en Guanajuato (2008–2013), Querétaro (2005–2013) y San Luis Potosí (2001–2013). Se confirmaron los casos por inmunofluorescencia directa. Se elaboraron mapas de distribución de los casos por año y por especie, mediante el software ArcMap versión 10.1. Para identificar áreas con condiciones apropiadas para la presencia de casos se combinaron las variables bioclimáticas con los casos georreferenciados, mediante el programa MaxEnt versión 3.3.3. Resultados. Se registraron 1 037 casos, de los cuales, 911 (87,9%) ocurrieron en San Luis Potosí, 82 (7,9%) en Querétaro y 44 (4,2%) en Guanajuato. Del total, 87,4% ocurrió en Alturas menores de 1 500 msnm. En Guanajuato y Querétaro, 77,3% y 42,3% de los casos, respectivamente, ocurrieron en alturas mayores de 1 500 msnm. Los meses de mayor incidencia fueron de diciembre a marzo. La variante antigénica viral V11 fue la más frecuente (173 casos), presente en los tres estados estudiados. En el canal endémico, el promedio de casos se mantiene en la zona de seguridad de enero a marzo, pero de abril a junio excede la mediana. La distribución espacial de los casos muestra la diseminación reciente de la enfermedad, lo que coincide con la presencia del murciélago vampiro. Conclusiones. La rabia paralítica bovina se ha extendido a regiones anteriormente libres de esta enfermedad. Las características ambientales y la altura sobre el nivel del mar no limitan la presentación de casos. Se debe mantener un monitoreo constante para la detección oportuna de casos. La vacunación se debe realizar antes del comienzo de las lluvias, sin esperar la aparición de brotes.

Objective. To determine the geospatial distribution of bovine paralytic rabies cases transmitted by Desmodus rotundus in the Mexican states of Guanajuato, Querétaro, and San Luis Potosí. Methods. This was a cross-sectional epidemiological study based on cases reported during statewide campaigns for the control of bovine paralytic rabies in Guanajuato (2008–2013), Querétaro (2005–2013) and San Luis Potosí (2001–2013). All cases were confirmed by direct immunofluorescence. Maps showing the distribution of cases by year and species were constructed using ArcMap version 10.1. To identify areas where conditions favor the appearance of cases, bioclimatic variables were combined with georeferenced cases using MaxEnt version 3.3.3. Results. Of the 1037 cases recorded, 911 (87.9%) occurred in San Luis Potosí, 82 (7.9%) in Querétaro, and 44 (4.2%) in Guanajuato. Of the total number of cases, 87.4% occurred at altitudes of less than 1500 meters above sea level. In Guanajuato and Querétaro, 77.3% and 42.3% of the cases, respectively, occurred at altitudes greater than 1 500 meters above sea level. Peak incidence was recorded from December to March. The V11 antigenic variant of the virus was the most common (173 cases); it was found in all three states. In the endemic channel, the average number of cases remains within the security zone from January to March but exceeds the median value from April to June. The spatial distribution of cases shows that the disease has spread recently, which correlates with the presence of the vampire bat. Conclusions. Bovine paralytic rabies has spread to areas that were formerly free of the disease. Environmental characteristics and the altitude above sea level do not limit the appearance of cases. Constant monitoring should be conducted for early case detection. Vaccination should take place before the rainy season starts, without waiting for outbreaks to occur.

What Can Proteomics Tell Us about Tuberculosis?

Tuberculosis (TB) is an infectious disease transmitted by aerosol droplets and characterized by forming granulomatous lesions. Although the number of people infected in the population is high, the vast majority does not exhibit symptoms of active disease and only 5-10% develop the disease after a latent period that can vary from weeks to years. The bases of the immune response for this resistance are unknown, but it depends on a complex interaction between the environment, the agent, and the host. The analysis of cellular components of M. tuberculosis shows important host-pathogen interactions, metabolic pathways, virulence mechanisms, and mechanisms of adaptation to the environment. However, the M. tuberculosis proteome still remains largely uncharacterized in terms of virulence and pathogenesis. Here, we summarize some of the major proteomic studies performed to scrutinize all the mycobacterial components.

[Epidemiological trends in bovine paralytic rabies in central Mexico, 2001-2013]. / Comportamiento epidemiológico de la rabia paralítica bovina en la región central de México, 2001-2013.

OBJECTIVE: To determine the geospatial distribution of bovine paralytic rabies cases transmitted by Desmodus rotundus in the Mexican states of Guanajuato, Querétaro, and San Luis Potosí. METHODS: This was a cross-sectional epidemiological study based on cases reported during statewide campaigns for the control of bovine paralytic rabies in Guanajuato (2008-2013), Querétaro (2005-2013) and San Luis Potosí (2001-2013). All cases were confirmed by direct immunofluorescence. Maps showing the distribution of cases by year and species were constructed using ArcMap version 10.1. To identify areas where conditions favor the appearance of cases, bioclimatic variables were combined with georeferenced cases using MaxEnt version 3.3.3. RESULTS: Of the 1037 cases recorded, 911 (87.9%) occurred in San Luis Potosí, 82 (7.9%) in Querétaro, and 44 (4.2%) in Guanajuato. Of the total number of cases, 87.4% occurred at altitudes of less than 1500 meters above sea level. In Guanajuato and Querétaro, 77.3% and 42.3% of the cases, respectively, occurred at altitudes greater than 1 500 meters above sea level. Peak incidence was recorded from December to March. The V11 antigenic variant of the virus was the most common (173 cases); it was found in all three states. In the endemic channel, the average number of cases remains within the security zone from January to March but exceeds the median value from April to June. The spatial distribution of cases shows that the disease has spread recently, which correlates with the presence of the vampire bat. CONCLUSIONS: Bovine paralytic rabies has spread to areas that were formerly free of the disease. Environmental characteristics and the altitude above sea level do not limit the appearance of cases. Constant monitoring should be conducted for early case detection. Vaccination should take place before the rainy season starts, without waiting for outbreaks to occur.

Efficacy of a vaccine formula against tuberculosis in cattle.

"Test-and-slaughter" has been successful in industrialized countries to control and eradicate tuberculosis from cattle; however, this strategy is too expensive for developing nations, where the prevalence is especially high. Vaccination with the Calmette-Guérin (BCG) strain has been shown to protect against the development of lesions in vaccinated animals: mouse, cattle and wildlife species. In this study, the immune response and the pathology of vaccinated (BCG-prime and BCG prime-CFP-boosted) and unvaccinated (controls) calves were evaluated under experimental settings. A 10(6) CFU dose of the BCG strain was inoculated subcutaneously on the neck to two groups of ten animas each. Thirty days after vaccination, one of the vaccinated groups was boosted with an M. bovis culture filtrate protein (CFP). Three months after vaccination, the three groups of animals were challenged with 5×10(5) CFU via intranasal by aerosol with a field strain of M. bovis. The immune response was monitored throughout the study. Protection was assessed based on immune response (IFN-g release) prechallenge, presence of visible lesions in lymph nodes and lungs at slaughter, and presence of bacilli in lymph nodes and lung samples in histological analysis. Vaccinated cattle, either with the BCG alone or with BCG and boosted with CFP showed higher IFN-g response, fewer lesions, and fewer bacilli per lesion than unvaccinated controls after challenge. Animals with low levels of IFN-g postvaccine-prechallenge showed more lesions than animals with high levels. Results from this study support the argument that vaccination could be incorporated into control programs to reduce the incidence of TB in cattle in countries with high prevalence.

Population structure of Mycobacterium bovis isolates from cattle in Mexico.

The molecular fingerprints of 878 isolates of Mycobacterium bovis collected from cattle between 2009 and 2010 in different regions of Mexico were used in this study. One hundred and ninety-four spoligotypes were observed in total with a high degree of heterogeneity. Sixty-four percent of the isolates grouped into just nine spoligotypes, and 27% fell into only two spoligotypes: SB0673 and SB0669; 149 were orphan spoligotypes. The two predominant spoligotypes were found in almost all states in Mexico, especially in central Mexico, where there is a high concentration of dairy cattle; however, some spoligotypes were closely associated with restricted geographical areas. The hypothetical evolutionary relationship among spoligotypes was estimated using the spoligoforest program in the spolTools webpage. Four trees with connected components and nine unconnected nodes were found. The biggest tree had SB0140 strain as a root, suggesting this as the oldest strain in the tree. However, the relationship of this spoligotype with SB0673 and SB0669 was weak. The discriminatory power of spoligotyping for this M. bovis sample of isolates was 0.94, and the recent transmission index (RTI) 0.83, suggesting a high rate of recent transmission of some strains of M. bovis in the population. This parameter indicates that new measures are required to stop the dissemination of tuberculosis in cattle.

European 1: a globally important clonal complex of Mycobacterium bovis.

We have identified a globally important clonal complex of Mycobacterium bovis by deletion analysis of over one thousand strains from over 30 countries. We initially show that over 99% of the strains of M. bovis, the cause of bovine tuberculosis, isolated from cattle in the Republic of Ireland and the UK are closely related and are members of a single clonal complex marked by the deletion of chromosomal region RDEu1 and we named this clonal complex European 1 (Eu1). Eu1 strains were present at less than 14% of French, Portuguese and Spanish isolates of M. bovis but are rare in other mainland European countries and Iran. However, strains of the Eu1 clonal complex were found at high frequency in former trading partners of the UK (USA, South Africa, New Zealand, Australia and Canada). The Americas, with the exception of Brazil, are dominated by the Eu1 clonal complex which was at high frequency in Argentina, Chile, Ecuador and Mexico as well as North America. Eu1 was rare or absent in the African countries surveyed except South Africa. A small sample of strains from Taiwan were non-Eu1 but, surprisingly, isolates from Korea and Kazakhstan were members of the Eu1 clonal complex. The simplest explanation for much of the current distribution of the Eu1 clonal complex is that it was spread in infected cattle, such as Herefords, from the UK to former trading partners, although there is evidence of secondary dispersion since. This is the first identification of a globally dispersed clonal complex M. bovis and indicates that much of the current global distribution of this important veterinary pathogen has resulted from relatively recent International trade in cattle.

Molecular epidemiology of human cases of tuberculosis by Mycobacterium bovis in Mexico.

The purpose of this study was to evaluate the role of Mycobacterium bovis in human cases of tuberculosis (TB) in an endemic area of the disease in cattle. Sputum, urine and other tissue samples were obtained from: (1) TB-symptomatic patients, (2) dairy farm workers and (3) abattoir workers. Samples of macroscopic lesions suspicious of TB were also obtained from cattle at slaughter in the same geographic area. A total of 562 human samples were collected: 255 from symptomatic patients, 218 from farm workers and 93 from abattoir workers. Samples were analysed by the bacillus acido-alcohol resitant (BAAR) and polymerase chain reaction (PCR) tests and cultured in Stonebrink and Löwenstein-Jensen. Spoligotyping was performed in all isolates obtained by culture and the DNA obtained by PCR. From the total number of human cases, 34 (6%) showed M. bovis spoligotype; eight spoligotypes from cattle showed an identical pattern to three spoligotypes from humans; a different set of spoligotypes from cattle (n = 8) had only one spacer difference to a set of spoligotypes from humans (n = 2). These results provide further evidence that infected cattle represent a risk to public health and support previous reports about the role of M. bovis in Mexican patients. There is no doubt that genotyping M. bovis isolates collected from cattle may have a substantial impact on our understanding of the epidemiology of TB.