Vibrio in seafood - FAO.org

More documents

Recommendations

Info

While these assumptions are not representative of what we believe is the nature of the humandose-response relationship, they form the basis of the first iteration of the hazard characterization. Asmore information becomes available, these assumptions will be revised to better reflect our understandingof dose-response relationships.2.3.3.2.3 Goodness of fit of the distributionThe goodness of fit of the distributions for all of the Vibrio spp. are uncharacterised as a family ofdose-response parameters are used to represent the parameter uncertainty.2.3.3.2.4 Uncertainty and variability in the estimatesThis analysis incorporates both uncertainty and variability in the estimates. Since the doseresponseestimates are based upon curves fitted to human volunteer data, there is uncertainty as to whetherthe parameters that give the best fit are the "true" parameters of the dose-response curve. To account forthis uncertainty, a Monte Carlo simulation model can be set up to probabilistically select from the group ofplausible dose-response parameters generated in this analysis. While it is not modelled in this analysis,there is variability in the virulence of the pathogens and in the susceptibility of the host. Further researchis needed to provide data for assessing and modelling variability in pathogen and in host. A keyuncertainty in this hazard characterization is the effect of the food matrix on the dose-responserelationship. Both the experience of the United Stated risk assessment on V. parahaemolyticus(Anonymous, 2001) and evidence from the studies of Cash, et al. (1974) have indicated that some foodmatrices may shift the dose-response curve to the left indicating that a higher dose of the pathogen isrequired to cause illness. Future human volunteer studies may help to resolve this question and providedata that will allow scaling factors to be applied to predict the risk for specific pathogens consumed withspecific food matrices.2.4 Risk characterizationto be completed in 20022.5 Gaps in the dataDeficiencies of the current research with respect to risk assessment were identified in order tosuggest future research or further data gathering to reduce uncertainties. They areas are as follows;• Incidence/frequency of pathogenic V. parahaemolyticus in water and shellfish.• Factors that affect incidence of pathogenic V. parahaemolyticus in the environment.• Role of oyster physiology and immune status in levels of V. parahaemolyticus. There is a need tocorrelate the number of V. parahaemolyticus with the percentage oysters diseased.• More research on the potential virulence factors of pathogenic strains other than TDH, e.g. urease,enterotoxins. V. parahaemolyticus strains that do not produce TDH, TRH, or urease have recentlybeen found to induce fluid accumulation in suckling mice and diarrhoea in a ferret model after oralinoculation in a dose-dependent manner (Kothary et al., 2000). Correlation between clinical andenvironmental incidence of these strains is yet to be determined.• Growth rate of V. parahaemolyticus within oysters at temperatures other than 26° C; including theissue of potential differences in the growth rate of pathogenic strains versus totalV. parahaemolyticus populations.42
• Rates of hydrographic flushing (water turnover) in shellfish harvest areas based on levels offreshwater flows, tidal changes, winds, depth of harvesting area and how these factors mayinfluence pathogenic V. parahaemolyticus numbers.• Consumer handling of oysters.• Improved global public health surveillance of V. parahaemolyticus to identify new epidemicstrains as they emerge.2.6 ReferencesAiso, K, and Fujiwara, K. 1996. Feeding tests of the pathogenic halophilic bacteria. Annual Research ReportInstitute of Food Microbiology Chiba University, 15:34-38.Abbott, S.L., Powers, C., Kaysner, C. A., Takeda, Y., Ishibashi, M. , Joseph, S. W., and Janda, J. M. 1989.Emergence of a restricted bioserovar of Vibrio parahaemolyticus as the predominant cause 2891ofVibrio-associated gastroenteritis on the West Coast of the United States and Mexico. Journal ofClinical Microbiology, 27: -2893Amako, K., Shimodori, Imoto, S. , Miake, T. , S. , and Umeda, A. 1987. Effects of chitin and its solublederivatives on survival of Vibrio cholerae O1 at low temperature. Applied and EnvironmentalMicrobiology, 53:603-605.Angulo F, and Evans M. 1999. Vibrio parahaemolyticus epidemiological data, personal communication. UnitedStates Centers for Disease Control and Prevention.Anonymous. 1996. Bol. Epidemiol. Semaenal., 4(46): 401.Anonymous. 1998a. Bol. Epidemiol. Semaenal, 6(31): 306.Anonymous. 1998b. National Nutrition Survey, Japan, The Ministry of Health and Welfare.Anonymous. 1999a. Vibrio parahaemolyticus, Japan 1996-1998, IASR Infectious Agents Surveillance Report.20 (7):1-2.Anonymous 1999b. Vibrio parahaemolyticus, Taiwan: Background. PROMED-digest, 28 May 1999.Anonymous. (2001) Draft Risk Assessment on the Public Health Impact of Vibrio parahaemolytius in rawmolluscan shellfish. Center for Food Safety and Applied Nutrition, U.S. FDA, Washington, DCBaffone, W., Pianetti, A., Bruscolini, F. , Barbieri, E. , and Citterio, B.. 2000. Occurrence and expression ofvirulence-related properties of Vibrio species isolated from widely consumed seafood products.International Journal of Food Microbiology, 54:9-18.Barker, W. H. 1974. Vibrio parahaemolyticus outbreaks in the United States., p. 47-52. In T. Fujino, G.Sakaguchi, R. Sakazaki, and Y. Takeda. (eds), International Symposium on Vibrio parahaemolyticus.Saikon Publishing Company, Tokyo.Barker, J & Brown, M.R.W. 1994. Trojan horses of the microbial world: protozoa and the survival of thebacterial pathogens in the environment. Microbiology, 140: 1253 - 1259.Barker, W. H., and Gangarosa, E. J. 1974. Food poisoning due to Vibrio parahaemolyticus. Annual Review ofMedicine, 25:75-81.Baross, J. A., J. Liston, and R. Y. Morita. 1978. Incidence of Vibrio parahaemolyticus bacteriophages and otherVibrio bacteriophages in marine samples. Applied and Environmental Microbiology, 36:492-499.Bates, T. C., Tolker-Nielsen, T., Molin, S., and Oliver, J. D. 2000. The viable but nonculturable state in Vibrioparahaemolyticus . Abstracts of the 100th General Meeting of the American Society for Microbiology.Abstract No. I-87:400.43
Page 1 and 2: Food and Agriculture Organization o
Page 3: 4.2.5 Simulation Results...........
Page 6 and 7: United States prior to 1997 illness
Page 8 and 9: 2 RISK ASSESSMENT OF VIBRIO PARAHAE
Page 10 and 11: The approach being taken is to use
Page 12 and 13: 2.2.2 Growth and survival character
Page 14 and 15: given average temperature and predi
Page 16 and 17: strains have been identified as a p
Page 18 and 19: 2001) and so this assumption may ha
Page 20 and 21: States. The study was undertaken on
Page 22 and 23: The estimated relationships between
Page 24 and 25: Clearly, in order to predict the di
Page 26 and 27: expected. Differences in these dist
Page 28 and 29: measurements were recorded for any
Page 30 and 31: egions of the country the average p
Page 32 and 33: etained. A corresponding air temper
Page 34 and 35: Frequency of duration of oysterharv
Page 36 and 37: 2.2.5.4.5 Die-off of V. parahaemoly
Page 38 and 39: V. parahaemolyticus cause illness -
Page 40 and 41: and four of those patients died. Pa
Page 42 and 43: Vomiting 52 17-79Headache 42 13-56F
Page 44 and 45: 2.3.3.2 Dose-response model2.3.3.2.
Page 48 and 49: Bean, N. H., Maloney, E. K., Potter
Page 50 and 51: Gjerde, E.P. and Bøe, B. 1981. Isp
Page 52 and 53: Levine, W. C., Griffin, P. M., and
Page 54 and 55: Abstract of the National Shellfishe
Page 56 and 57: 3.1.2 Prevalence in foodAlthough li
Page 58 and 59: The concentration of V. parahaemoly
Page 60 and 61: Figure 3.3. Schematic representatio
Page 62 and 63: 3.2.4 Preparation and consumption m
Page 64 and 65: • Frequency of consumption of raw
Page 66 and 67: Sarkar, B. L., G. B. Nair, et al..
Page 68 and 69: foodborne case has been associated
Page 70 and 71: (Cook and Ruple, 1992). However, th
Page 72 and 73: 4.2.4.1 HarvestLike V. parahaemolyt
Page 74 and 75: Although not incorporated in the pr
Page 76 and 77: increase in log of Vv density32.521
Page 78 and 79: Figure 4.6 shows typical distributi
Page 80 and 81: 1.5Probability Density0.7501 2 3 4
Page 82 and 83: Table 4.6. Prevalence rates of V. v
Page 84 and 85: 4.3.3 Dose-response relationship4.3
Page 86 and 87: Dec 15 0.76 0.61 1,841,000 1,025,00
Page 88 and 89: • Does virulence vary by season,
Page 90 and 91: ICMSF. 1996. Microorganisms in Food
Page 92 and 93: Appendix.Analytica 2.0.5 Model Simu
Page 94 and 95: The chance nodes representing varia
Page 96 and 97:
5.2.2.2 Death or inactivationV. cho
Page 98 and 99:
Table 5.3. Instances of fish implic
Page 100 and 101:
Shrimp harvested fromcoastal areas
Page 102 and 103:
O1 through poor quality water, and
Page 104 and 105:
5.3.1.2 Characteristics of the host
Page 106 and 107:
5.3.3.1.4 Probability of death give
Page 108 and 109:
Resampled Beta-Poisson dose-respons
Page 110 and 111:
De Paola, A. 1981. Vibrio cholerae
Page 112:
Reilly, L.A. and Hackney, C.R. 1985
show all

Vibrio in seafood - FAO.org

Create successful ePaper yourself

Delete template?

Save as template?