Comparative Field Trial Effect of <em>Brucella</em> spp. Vaccines on Seroconversion in Goats and Their Possible Implications to Control Programs

The aim of this study was to determine the seroprevalence of Brucella spp. in a goat flock and the seroconversion of three groups of animals vaccinated with Rev-1 (Brucella melitensis), RB51, and RB51-SOD (Brucella abortus) to estimate the level of protection conferred on susceptible females. Seventy-two animals were used by group. Goats were older than 3 months, seronegative to brucellosis, not vaccinated previously, and kept within positive flocks. Vaccinated animals received 2 mL of product subcutaneously in the neck region. The first block was injected with Rev-1; the second received RB51, and the third group was injected with RB51-SOD. Follow-up sampling was performed at 30, 60, 90, and 365 days postvaccination. The general prevalence of brucellosis for the three groups was 1.2% (95%CI:0.5–2.7). The seroconversion rate by day 30 after vaccination was 77.7% (95%CI:61.9–88.2) for goats vaccinated with Rev-1. At 365 days post vaccination, the percentage of seropositive goats declined to 13.8% (95%CI:6.0–28.6). At day 365 after vaccination, 2.7% (95%CI:0.4–14.1) and 5.5% (95%CI:1.5–18.1) of animals vaccinated with RB51 and RB51-SOD, respectively, became positive. Results show that the seroconversion induced by Brucella abortus RB51 and RB51-SOD vaccines is lower than that by Brucella melitensis Rev-1

Estimación del riesgo microbiológico asociado al consumo de ostión crudo contaminado con Vibrio cholerae y Vibrio parahaemolyticus

The aim of the study was to assess the potential riskof exposure to V. cholerae and V. parahaemolyticus associated to raw American oyster (Crassostrea virginica) consumption collected from the Mandinga Lagoon System (MLS), in restaurants, oyster bars, and street vendors. Risk was estimated as number of cases/100,000 servings with FDA model. The risk of oyster consumption from MLS contaminated with V.cholerae noO1/noO139 chxA+ and unrefrigerated 10-h was low (99 × 10-5 cases) in summer; V. parahaemolyticus tdh+ y tdh+/trh+ estimated risk was high in spring (2,200 × 10-5 y 4,000 × 10-5 cases, respectively) and the pandemic strain orf8+ risk was medium in winter (110 × 10-5 cases). Oyster cocktailconsumption unrefrigerated for 10 h and contaminated with V. cholerae noO1/noO139 chxA+, represented a low mean risk (0.87 × 10-5 and 0.44 × 10-5 cases) for oyster cocktails from restaurants and oyster bars, respectively, a high mean risk forstreet vendor cocktails stored at ambient temperature 24 h (2,500 × 10-5 cases), and a low mean risk for V. parahaemolyticus tdh+ in restaurants (0.21 × 10-5 cases) and oyster bar (1.1 × 10-5 cases) cocktails. Risk assessment results indicated that pathogenic percentage, type of establishment, and unrefrigerated storage time were variables that most increased the probability of illness, and spring the season with the highest risk for consumers.El objetivo del estudio fue predecir el riesgo potencial de exposición a V. cholerae y V. parahaemolyticus asociado al consumo de ostión americano (Crassostrea virginica) crudo colectado del Sistema Lagunar Mandinga (SLM), en restaurantes, coctelerías y puestos ambulantes. El riesgo se estimó como casos esperados/100,000 porciones con el modelo de la FDA. En ostiones del SLM el riesgo estimado por consumir ostiones contaminados con V. cholerae noO1/noO139 chxA+ sin refrigerar 10 h en verano fue bajo (99×10-5 casos); V. parahaemolyticus tdh+ y tdh+/trh+ representaron un riesgo estimado alto en primavera (2,200×10-5 y 4,000×10-5 casos, respectivamente) y la cepa pandémica orf8+ un riesgo medio (110×10-5 casos) en invierno. El consumo de ostión crudo sin refrigerar 10 h contaminado con V. cholerae noO1/noO139 chxA+ representó un riesgo promedio bajo (0.87×10-5 y 0.44×10-5 casos) para restaurantes y coctelerías, respectivamente, alto para cocteles expendidos en puestos ambulantes a temperatura ambiente 24 h (2,500×10-5 casos) y bajo a V. parahaemolyticus tdh+ en restaurantes (0.21×10-5 casos) y coctelerías (1.1×10-5 casos). El porcentaje patogénico, el sitio de venta y el tiempo sin refrigerar fueron las variables que incrementaron el riesgo de enfermar, siendo primavera la estación con el mayor riesgo para el consumidor

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 &lt; 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 &lt; 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 &lt; 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 (&lt; 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 &lt; 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 &lt; 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

Detection of Bartonella bovis DNA in blood samples from a veterinarian in Mexico

The genus Bartonella encompasses 38 validated species of Gram-negative, facultative intracellular bacteria that colonize the endothelial cells and erythrocytes of a wide spectrum of mammals. To date, 12 Bartonella species have been recorded infecting humans, causing diseases of long historical characterization, such as cat scratch fever and trench fever, and emerging bartonellosis that mainly affect animal health professionals. For this reason, this study aimed to report a documented case of Bartonella bovis infecting a veterinarian from Mexico by the amplification, sequencing and phylogenetic reconstruction of the citrate synthase (gltA) and the RNA polymerase beta-subunit (rpoB) genes, and to report the natural course of this infection. To our knowledge, this work is the first to report the transmission of B. bovis via needlestick transmission to animal health workers in Latin America

Influence of environmental factors on the presence of Vibrio cholerae in the marine environment: a climate link

Evidence indicates that the atmospheric and oceanic processes that occur in response to increased greenhouse gases in the broad-scale climate system may already be changing the ecology of infectious diseases. Recent studies have shown that climate also influences the abundance and ecology of pathogens, and the links between pathogens and changing ocean conditions, including human diseases such as cholera. Vibrio cholerae is well recognized as being responsible for significant mortality and economic loss in developing countries, most often centered in tropical areas of the world. Within the marine environment, V. cholerae is found attached to surfaces provided by plants, filamentous green algae, copepods, crustaceans, and insects. The specific environmental changes that amplified plankton and associated bacterial proliferation and govern the location and timing of plankton blooms have been elucidated. Several studies have demonstrated that environmental non-O1 and non-O139 V. cholerae strains and V. cholerae O1 El Tor and O139 are able to form a three-dimensional biofilm on surfaces which provides a microenvironment, facilitating environmental persistence within natural aquatic habitats during interepidemic periods. Revealing the influence of climatic/environmental factors in seasonal patterns is critical to understanding temporal variability of cholera at longer time scales to improve disease forecasting. From an applied perspective, clarifying the mechanisms that link seasonal environmental changes to diseases’ dynamics will aid in developing strategies for controlling diseases across a range of human and natural systems

Effect of pasteurization on the concentration of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) in bovine milk

El Diclorodifeniltricloroetano (DDT) y Hexaclorociclohexano (HCH) son disruptores endócrinos cuya presencia en la leche representa un riesgo para la salud. Existe evidencia de que la pasteurización disminuye o incrementa la concentración de plaguicidas organoclorados en productos lácteos. La presente investigación evaluó el efecto de la pasteurización a 63 °C 30 min-1 y 73 °C 15 seg-1 en las concentraciones de DDT, HCH y sus metabolitos en leche bovina, para estimar la exposición dietaria por consumo humano de leche pasteurizada. Se realizó un diseño experimental de bloques al azar con dos tratamientosen 100 muestras de leche recolectadas en Soledad de Doblado y Jamapa, Veracruz, México. Los plaguicidas se cuantificaron por cromatografíade gases con detector de microcaptura de electrones. Los datos se analizaron mediante Análisis de Varianza unifactorial (P<0.05) y las medias se compararon con Tukey (P< 0.05). La exposición dietaria a plaguicidas se evaluó por laIngesta Diaria Estimada (IDE) y Dosis Diaria Promedio (DDP) en tres grupos de población. La pasteurización a 73 ºC disminuyó 30.94, 44.51, 3.18, 81.23 y 42.82 % las concentraciones de p,p'-DDE,p,p'-DDD, o,p'-DDT, p,p'-DDT y DDT total, respectivamente, así como las concentraciones de β-HCH, γ-HCH y HCH total (85.68, 18.88 y 99.31 %, respectivamente). La IDE para niños, adultos y ancianos de DDT total fue menor por consumo de leche pasteurizada a 73 ºC y de γ-HCH a 63 ºC. La DDP de DDT total disminuyó con la pasteurización a 73 °C. La exposición dietaria de DDT y HCH fue mayor en niños.Dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) are endocrine disruptors whose presence in milk entails a health risk. There is evidence that pasteurization decreases or increases the concentration of organochlorine pesticides in dairy products. The present research evaluated the effect of pasteurization at 63 °C 30 min-1 and 73 °C 15 sec-1 on the concentrations of DDT, HCH and their metabolites in bovine milk, in order to estimate the dietary exposure from human consumption of pasteurized milk. A completely randomized experimental design with two treatments was performed on 100 milk samples collected in Soledad de Doblado and Jamapa, Veracruz, Mexico. Pesticides were quantified by gas chromatography with an electron microcapture detector. Data were analyzed by single-factor analysis of variance (P<0.05), and means were compared with Tukey’s test (P<0.05). The dietary exposure to pesticides was assessed based on the estimated daily intake (EDI) and average daily dose (ADD) in three population groups. Pasteurization at 73 ºC reduced the concentrations of p,p'-DDE, p,p'-DDD, o,p'-DDT, p,p'-DDT and total DDT by 30.94, 44.51, 3.18, 81.23, and 42.82 %, respectively, as well as the concentrations of β-HCH, γ-HCH and total HCH (by 85.68, 18.88, and 99.31 %, respectively). The EDI of total DDT by children, adults,  and elderly people was lowest for consumption of milk  pasteurized at 73 °C, and that of γ-HCH, for milk pasteurized at 63 °C. The DDP of total DDT decreased with pasteurization at 73 °C. The dietary exposure to DDT and HCH was higher in children

Microbial risk assessment of Vibrio spp. in seafood products in Mexico

Food-borne diseases are among the major public health problems that currently exist. Microbiological risk assessment is a process used to evaluate the hidden hazards in food, the likelihood of exposure to these hazards and their impact on public health. Risk assessment is performed in four steps: hazard identification, hazard characterization, assessment of exposure and risk characterization. According to the process/response microbial risk assessment is classified in two categories, qualitative and quantitative. The aim of this review is to underline the importance of implementing assessments in seafood that is usually consumed raw, strengthening access to good quality and safe food for the consumer’s benefit and to stress the necessity of microbiological risks assessments in Mexico

Crecimiento y sobrevivencia de Vibrio parahaemolyticus en ostión americano (Crassostrea virginica) almacenada en refrigeración

Objetivo. Cuantificar las densidades de Vibrio parahaemolyticus en ostión americano (Crassostrea virginica) almacenado en refrigeración. Material y métodos. Se almacenaron 320 ostiones a 7 °C durante nueve días y se determinaron las densidades totales y patogénicas mediante la técnica NMP-PCR. Resultados. Se observaron densidades de V. parahaemolyticus tlh+ en los días 0, 3 y 6 de almacenamiento con 1.134, 2.764 y 0.785 log10NMP/g, respectivamente, y en los días 0 y 3 la densidad patogénica trh+ con 0.477 y 0.519 log10NMP/g, respectivamente; las densidades patogénicas tdh+ (0.519 log10NMP/g), tdh+/trh+ (0.519 log10NMP/g) y tdh+/orf8+ (-0.444 log10NMP/g) se detectaron al tercer día de almacenamiento. Conclusión. Los resultados sugieren que el crecimiento de V. parahaemolyticus y la ocurrencia de genes patogénicos a 7 °C involucran cambios en la expresión génica como una respuesta al estrés por frío. Esto contribuye a la sobrevivencia y virulencia de V. parahaemolyticus, lo cual representa un riesgo a la salud pública

Evaluación de indicadores productivos en rebaños caprinos vacunados con cepas RB51–SOD, RB51 (Brucella abortus) y Rev-1 (Brucella melitensis)

Kidding rates, miscarriages and births of weak offspring were determined in herds vaccinated with the RB51-SOD (B. abortus) strain in order to evaluate the productive improvement and compare it with Rev-1 (B. melitensis) and RB51 (B. abortus) vaccines. Three subgroups of 36 goats each were vaccinated with Rev-1 (1-2x109 CFU), RB51 (3x108-3x109 CFU) and RB51-SOD (3x108-3x109 CFU) strains, with each strain having a control subgroup. Individual records were established for calculating post-vaccination rates in two kidding seasons.  In the first, the kidding  rate for Rev-1  was 66.6 %  (95%CI: 48.9-80.9),  RB51 50.0 % (95%CI:33.2-66.7), and RB51-SOD 69.4 % (95%CI:51.7-83.0). Miscarriages occurred in all three vaccinated subgroups, Rev-1 and RB51-SOD 5.5 % (95%CI: 0.9-20.0) and RB51 2.7 % (95%CI: 0.1-16.2). Weak offspring births occurred only in animals vaccinated with Rev-1 5.5 % (95%CI: 0.9-20.0). During the second epoch, the kidding rate in Rev-1 vaccinated females was 91.6 % (95% CI:76.4-97.8), RB51 94.4 % (95% CI:79.9-99.0), and RB51-SOD 94.4 % (95% CI:79.9-99.0). Animals vaccinated with Rev-1 and RB51 strains had 5.5 % (95%CI: 0.9-20.0) and 2.7 % (95%CI: 0.1-16.2) miscarriages, respectively; in vaccinated subgroups there were no births of weak offspring. The control subgroups behaved similarly to the vaccinated subgroups. Animals vaccinated with the RB51-SOD strain showed no significant difference from those that received the Rev-1 and RB51 strains, nor from the control subgroups (P>0.01); therefore, the RB51-SOD vaccine can generate protection against brucellosis and benefits in the production of goat herds.Se determinaron tasas de pariciones, abortos y nacimiento de crías débiles en rebaños vacunados con la cepa RB51–SOD (B. abortus) para evaluar la mejora productiva y compararla con las vacunas Rev–1 (B. melitensis) y RB51 (B. abortus). Se vacunaron tres subgrupos de 36 cabras cada uno con cepas Rev–1 (1–2x109 UFC), RB51 (3x108-3x109 UFC) y RB51–SOD (3x108-3x109 UFC), cada cepa tuvo un subgrupo control. Se establecieron registros individuales para calcular las tasas posvacunación en dos épocas de pariciones. En la primera, la tasa de partos para Rev-1 fue 66.6 % (IC95%: 48.9–80.9), RB51 50.0 % (IC95% :33.2–66.7) y RB51-SOD 69.4 % (IC95% :51.7–83.0). Los abortos se presentaron en los tres subgrupos vacunados, Rev-1 y RB51-SOD 5.5 %  (IC95% :0.9–20.0)  y  RB51 2.7 % (IC95%: 0.1–16.2). Los nacimientos de crías débiles se presentaron solo en animales vacunados con Rev-1 5.5 % (IC95%: 0.9–20.0). Durante la segunda época, la tasa de partos en hembras vacunadas con Rev-1 fue de 91.6 % (IC95% :76.4–97.8), RB51 94.4 % (IC95% :79.9–99.0) y RB51-SOD 94.4 % (IC95% :79.9–99.0). Tuvieron abortos animales vacunados con cepas Rev-1 y RB51, 5.5 % (IC95%: 0.9–20.0) y 2.7 % (IC95%: 0.1–16.2), respectivamente; en subgrupos vacunados no hubo nacimiento de crías débiles. Los subgrupos controles tuvieron un comportamiento similar a los vacunados. Los animales vacunados con la cepa RB51–SOD no mostraron diferencia significativa con los que recibieron las cepas Rev-1 y RB51, ni con los subgrupos control (P>0.01); por lo anterior, la vacuna RB51-SOD puede generar protección contra la brucelosis y beneficios en la producción de rebaños caprinos