Molecular detection of bovine leukosis virus in naturally infected dairy and dual-purpose cattle in Mexico.

The objective of this study was to determine the prevalence of bovine leukosis virus (BLV) in specialized and dual-purpose dairy cows located in the central zone of Veracruz state in Mexico, using endpoint polymerase chain reaction (PCR). The study population consisted of 307 specialized dairy cows and 95 dual-purpose cows from 13 municipalities located in the study area. All cows were apparently healthy and ≥ 3 years old. Cows were stratified by age (3 - 5, 6 - 8 and ≥ 9 years). The overall prevalence of infection was 6.96%; the calculated prevalence in dairy cows was 7.82% and in dual-purpose cows it was 4.21%. The municipality with the highest proportion was Acajete (14.28%), followed by Huatusco and Tomatlán (11.53%). The association analysis confirms the infection's independence to the cows' productive purpose. The results by age strata were 3 - 5 (4.60%), 6 - 8 (8.00%) and ≥ 9 (18.40%) with X2 = 9.96, with an odds ratio of 4.68 for the stratum ≥ 9 years with a significant difference. The present study determined the prevalence of proviral DNA of BLV in dairy and dual-purpose cows in six municipalities in the central zone of Veracruz state, Mexico, using endpoint PCR.

Spatial distribution models of seroreactive sheep to Leptospira spp. in Veracruz, Mexico.

Leptospirosis is an infectious zoonotic disease of special importance in tropical regions of the world and is closely related to climatic conditions. In Mexico, at least eight Leptospira serogroups are known to affect sheep, but little is known about their distribution. The aim was to analyse the spatial distribution of seroreactive sheep to eight serogroups of Leptospira spp. through ecological niche modelling from the state of Veracruz. We carried out a cross-sectional, multistage, and stratified epidemiological study, sampling 405 sheep in different regions of the state (north, center, and south). The sera were analysed using the microscopic agglutination test (MAT) to identify seropositivity to eight Leptospira serogroups (Icterohaemorrhagiae, Pyrogenes, Grippotyphosa, Canicola, Pomona, Hardjo, Wolffi, and Tarassovi). Management variables in the sampled herds were evaluated through a survey among the producers, which was analysed using the chi-squared test for cross-tabulation. Geospatial modelling was conducted using MAXENT and 19 climatic variables, and validation was carried out using the area under the curve (AUC). No positive animals were found for Pomona in any area of Veracruz, and there was only one case of seroreactivity to Grippotyphosa. The total seroprevalence found was 53.83% (95% confidence interval [CI] 48.84-58.75). The main serogroup found was Sejroe (55.31%, 95% CI 50.32-60.20%), followed by Canicola (8.64%, 95% CI 6.17-11.92%), Icterohaemorrhagiae (4.69%, 95% CI 2.93-7.36%), Tarassovi (3.95%, 95% CI 2.35-6.47%), Pyrogenes (2.47%, 95% CI 1.26-4.64%), Australis (0.99%, 95% CI 0.32-2.69%), and Grippotyphosa (0.25%, 95% CI 0.01-1.59%). The predictive model for Australis was not significant. Acceptable predictive models (AUC > 0.7-0.8) were found for Canicola, Icterohaemorrhagiae, Pyrogenes, and Tarassovi, while for Sejroe, it was excellent (AUC > 0.85); consequently, the climatic variables that most contributed to the model were those related to precipitation. The potential distribution of Pyrogenes, Icterohaemorrhagiae, and Canicola was located to a greater extent in the three regions; Pyrogenes and Tarassovi were distributed mostly in the north and central regions, and Sejroe was mostly located in the center and south of the state. Ecological niche modelling could support epidemiological control and surveillance programs for affected sheep herds in the state of Veracruz.

Seroprevalence and risk factors associated with Toxoplasma gondii infection in sheep of Veracruz State, southeast Mexico.

Toxoplasma gondii is widely prevalent in sheep and their products pose a risk to public health. The aim of this study was to identify the seroprevalence and risk factors associated with T. gondii infection in sheep in Veracruz State, Mexico. The study was cross-sectional and it was carried out in thirteen municipalities distributed in three regions of Veracruz State. A total of 414 blood samples were collected from four districts of Veracruz State and analyzed for T. gondii antibodies using enzyme-linked immunosorbent assay. Total seroprevalence was 35.90% (149/414; 95.00% CI = 31.40-40.80). Seroprevalence by the municipality was 10.50% to 85.70% and for the district was 28.80% to 47.80%, respectively. Age, breed and productive status were identified as risk factors associated with T. gondii infection significantly. The infection by T. gondii is widely present in the districts of the Veracruz State with a high seroprevalence and risk factors associated with infection.

Comparative Survival and the Cold-Induced Gene Expression of Pathogenic and Nonpathogenic Vibrio Parahaemolyticus from Tropical Eastern Oysters during Cold Storage.

Expression of the regulatory stress rpoS gene controls the transcription of cspA genes, which are involved in survival and adaptation to low temperatures. The purpose of this study was to assess the growth kinetics of naturally occurring V. parahaemolyticus in shellstock oysters and in vitro and the cold-shock-induced expression of the rpoS and cspA gene response in vitro during postharvest refrigeration. Naturally contaminated eastern oysters (Crassostrea virginica) and pathogenic (Vp-tdh) and nonpathogenic (Vp-tlh) isolates were stored at 7 ± 1 °C for 168 h and 216 h, respectively. The regulatory stress (rpos) and cold-shock (cspA) gene expressions were determined by reverse transcription PCR. At 24 h, the (Vp-tdh) strain grew faster (p < 0.05) than the (Vp-tlh) strain in oysters (λ = 0.33, 0.39, respectively) and in vitro (λ = 0.89, 37.65, respectively), indicating a better adaptation to cold shock for the (Vp-tdh) strain in live oysters and in vitro. At 24 h, the (Vp-tdh) strain rpoS and cspA gene expressions were upregulated by 1.9 and 2.3-fold, respectively, but the (Vp-tlh) strain rpoS and cspA gene expressions were repressed and upregulated by -0.024 and 1.9-fold, respectively. The V. parahaemolyticus strains that were isolated from tropical oysters have adaptive expression changes to survive and grow at 7 °C, according to their virulence.

Improved Microbial Safety of Direct Ozone-Depurated Shellstock Eastern Oysters (Crassostrea virginica) by Superchilled Storage.

The effect of superchilled storage at -1°C on the microbial safety of oyster depurated with 0.2, 0.4, and 0.6 mg/L ozone was studied for 14 days. Fecal coliforms (4,100-16,000 MPN/100 g), Escherichia coli (1,500-3,650 MPN/100 g), Vibrio cholerae non-O1/non-O139 (13.0-102.0 MPN/g), and Salmonella spp. (2.270-3.035 × 103 CFU/g) were initially present in raw oysters. After 6 h depuration, fecal coliform counts decreased (P < 0.05) to 300, 20 and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, while a 0.3 log decrease in control oysters was observed. Initial E. coli counts decreased (P < 0.05) in oysters to 50, 20, and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, respectively. A 1 log reduction in V. cholerae non-O1/non-139 levels were observed in 0.4 and 0.6 mg/L-treatments after 2 and 4 h depuration. Salmonella spp. was not detected in oyster samples after 6 h depuration in 0.4 and 0.6 mg/L-ozone treatments. Considering the bacterial loads after depuration, at the end of superchilled storage the 0.4 mg/L-ozonated oysters attained lower (P < 0.05) fecal coliform levels (280 MPN/100 g) and E. coli counts in 0.4 and 0.6 mg/L-ozonated oysters (20 and 95 MPN/100 g, respectively). A 2-log decrease in V. cholerae non-O1/non-O139 levels on day 5 in 0.4 and 0.6 mg/L-ozonated oysters (< 0.3 MPN/g) was attained. V. cholerae non-O1/non-O139 counts in control oysters decreased 1 log on day 9 of superchilled storage. Salmonella spp. was not detected in ozonated and superchilled stored oysters. Levels of fecal coliforms, E. coli, Salmonella spp., and V. cholerae non-O1/non-O139 in non-ozone depurated oyster samples were higher than in control, 0.4 and 0.6 mg/L ozonated oyster samples during superchilled storage. The cumulative mortality rates after 14 days of storage for superchilled oysters (22.2%) was higher (P < 0.05) than 0.6 mg/L O3 (7.2%) and 0.4 mg/L O3 (5.8%) treatments, and control oysters (5.6%). pH values in control oysters decreased significantly (P < 0.05) throughout the storage period but not in oysters of both ozone treatments, indicating no detrimental effects on oyster survival. The results of this study suggest that superchilled storage enables ozonated shellstock oysters (0.4 mg/L-6 h) stored for 9 days to be safe human consumption.

[Epidemiology of caprine brucellosis in the Central Zone of the State of Veracruz]. / Epidemiología de la brucelosis caprina en la Zona Centro del Estado de Veracruz.

INTRODUCTION: Brucellosis is a disease of high morbidity that affects several animal species, is transmitted to humans and, therefore, is a zoonosis. It is caused by bacteria of the genus Brucella. In this study we aim to determine seroprevalence, risk factors, and spatial distribution of caprine brucellosis in 14 municipalities in the central region of the state of Veracruz. MATERIALS AND METHODS: This cross-stratified multistage study was conducted between 2009 and 2012. It included 572 animals of 81 production units selected by consensus according to the value tables of ​​Cannon and Roe. The diagnosis was by Card Testing and Radial Immunodiffusion. The seroprevalence was determined with the VassarStats® risk factor program and odds. RESULTS: The overall seroprevalence was 0.52% (95% CI: 0.13-1.65) and production units 2.47% (95% CI: 0.43-9.46). They were identified as risk factor for infection, production units in feedlot system and Card Testing seroconversion to vaccine against brucellosis; and as a protective factor, vaccination. CONCLUSIONS: Seroprevalence and distribution of goat brucellosis is low, the intensive system is a risk, and according with the Health Ministry in order that human cases are scarce.

Environmental parameters influence on the dynamics of total and pathogenic Vibrio parahaemolyticus densities in Crassostrea virginica harvested from Mexico's Gulf coast.

The influence of environmental parameters on the total and pathogenic Vibrio parahaemolyticus seasonal densities in American oysters (Crassostrea virginica) was evaluated for 1 year. Harvesting site A yielded the highest mean densities of V. parahaemolyticus tlh+, tdh+/trh-, tdh-/trh+ and tdh+/trh+ during spring season at 2.57, 1.74, 0.36, and -0.40 log10 MPN/g, respectively, and tdh+/orf8+ during winter season (0.90 log10 MPN/g). V. parahaemolyticus tlh+ densities were associated to salinity (R(2)=0.372, P<0.022), tdh+/trh+ to turbidity (R(2)=0.597, P<0.035), and orf8+ to temperature, salinity, and pH (R(2)=0.964, P<0.001). The exposure to salinity and temperature conditions during winter and spring seasons regulated the dynamics of V. parahaemolyticus harboring potentially pathogenic genotypes within the oyster. The adaptive response of V. parahaemolyticus to seasonal environmental changes may lead to an increase in survival and virulence, threatening the seafood safety and increasing the risk of illness.

Physiological effects of constitutive expression of Oilseed Rape Mosaic Tobamovirus (ORMV) movement protein in Arabidopsis thaliana.

Movement proteins (MPs) are non-cell autonomous viral-encoded proteins that assist viruses in their cell-to-cell movement. The MP encoded by Tobamoviruses is the best characterized example among MPs of non-tubule-inducing plant RNA viruses. The MP of Oilseed Rape Mosaic Tobamovirus (ORMV) was transgenically expressed in Arabidopsis thaliana, ecotype RLD, under the expression of the 35S promoter from Cauliflower Mosaic Virus. Transgenic lines were obtained in sense and antisense orientations. One of the sense transgenic lines was further characterized turning out to carry one copy of the transgene inserted in the terminal region of the right arm of chromosome 1. The constitutive expression of ORMV-MP induced mild physiological effects in Arabidopsis. Plants of the transgenic line allowed a faster systemic movement of the phloem tracer carboxyfluorescein. The tracer was unloaded differentially in different flower parts, revealing differential effects of ORMV-MP on phloem unloading in sink organs. On the other hand, transgenic Arabidopsis did not show any effect on biomass partitioning or sugar availability, effects reported for equivalent transgenic solanaceous plants expressing the MP of Tobacco Mosaic Virus, another Tobamovirus. Finally, the transgenic Arabidopsis plants were susceptible to ORMV infection, although showing milder overall symptoms than non-transgenic controls. The results highlight the relevance of the specific host-virus system, in the physiological outcome of the molecular interactions established by MPs.