Chapters authored
Survival Differences of Vibrio vulnificus and Vibrio parahaemolyticus Strains in Shellstock Oysters (Crassostrea virginica) from Harvest to Sale: A Risk Perspective
As there is limited information on the risk for consuming market oysters contaminated with V. vulnificus and V. parahaemolyticus, the aim of this study was to estimate the risk associated with raw oyster consumption affected by contamination levels and temperature during postharvest and transportation. To evaluate the effect of the temperature during transportation from the Mandinga Lagoon to Mexico City on the growth of V. vulnificus and V. parahaemolyticus, a modified Gompertz model was fitted at ambient temperatures of 20.1, 25.6, and 24.4°C for 22 h in windy, dry, and rainy seasons, respectively. The risk was calculated using FDA/FAO/WHOv.2005 software. Results showed that the mean risk (cases per 100,000 servings) of a person acquiring V. vulnificus vvha+/cvgC infection by consuming raw oysters was 2.9 × 10−6, 4.7 × 10−6, and 4.3 × 10−6 during windy, dry, and rainy seasons, respectively. Risk for consuming oysters during windy season at-harvest contaminated with V. parahaemolyticus tdh+ was 8 × 10−6 and 7.8 × 10−7 for consuming oysters at-market during rainy season contaminated with V. parahaemolyticus tdh+ and trh+. These results suggest that maintaining temperatures above 20°C during oyster storage and transportation increases the risk of infections by pathogenic strains. The results provide a benchmark information to establish strategies to improve public health.
Part of the book: Molluscs
Comparative Field Trial Effect of Brucella 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.
Part of the book: New Insight into Brucella Infection and Foodborne Diseases