Pathogens outbreak

Disease control in aquaculture aims to mitigate the effects of pathogen outbreaks throughout the production cycle and improve productivity. Disease is a major issue in aquaculture as in all intensive culture systems and accounts for significant mortalities and economic loss in industry. The availability of microarray technology has provided tools for researchers to describe viral, bacterial and parasitic disease processes in a number of host... 

However, very little evidence exists to indicate that current water treatment practices are inadequate (no outbreaks of viral or protozoal infections have been reported and waterborne diseases attributed to these pathogens are rare in this country). 

Abundant literature on the increase of the densities of faecal pathogens and indicators in water sources during dry and rainy periods and the significant effect of rain in water-borne infectious disease outbreaks exist and prove all these assertions. 

NoV outbreaks in hospital settings can be expensive, with one case report identifying costs totaling over 650,000 for a single outbreak (Johnston et ah, 2007). A 2007 review found that NoV outbreaks in hospitals had a 44% rate of requiring unit closures, much higher than the rates for other nosocomial pathogens (Hansen et ah, 2007). 

Gallay, A., E)e Valk, H., Cournot, M., Ladeuil, B., Hemery, C., Castor, C., Bon, F., Megraud, F., Le Cann, P., and Desenclos, J. C. (2006). A large multi-pathogen waterborne community outbreak linked to faecal contamination of a groundwater system, France, 2000. Clin. Microbiol. Infect. 12, 561-570. 

EHEC are the pathogenic subgroup of Stx-producing E. coli (STEC). Acute hemorrhagic colitis has been associated mainly with the 0157 H7 serotype. This serotype has been responsible for larger outbreaks of infection, has higher rates of complications, and appears to be more pathogenic than non-EHEC STEC strains. The spectrum of disease associated with E. coli 0157 H7 includes bloody diarrhea, which is seen in as many as 95% of patients, nonbloody diarrhea, hemolytic-uremic syndrome (HUS), and thrombotic thrombocytopenic purpura. 

The Centers for Disease Control (CDC) in the USA has estimated that Campylobacter and Salmonella are the top two bacterial foodbome pathogens as they are responsible for a total of 2 and 1.3 million foodbome infections every year (Mead et al., 1999). Most of the cases of infection with Campylobacter and Salmonella appear to be due to eggs and poultry, but a significant number of cases are related to beef products (CDC, 2005 Jay, 2000). EHEC does not cause as many infections as the top two pathogens (approximately 100,000 in the USA), but EHEC is frequently linked to outbreaks of diarrhea caused by the consumption of contaminated ground beef (Mead et al., 1999, Rangel et al., 2005). Infections caused by EHEC are the major microbial public health concern related to ruminant food products. 

Pathogen contamination can occur at every stage of the whole production chain from field-to-fork (Table 19.1). Nevertheless, besides other components of infection, manures derived from livestock are considered to be an important potential preharvest contamination source (Fig. 19.1). Several disease outbreaks have been associated with raw fruits and vegetables and unpasteurised products some have been traced back to livestock (Pell, 1997), but in the majority of the outbreaks associated with fresh produce, minimally processed products and unpasteurised products, the source of contamination remains unknown (de Roever, 1998). 

Harris LJ, Farber JN, Beuchat LR, Parish ME, Suslow TV, Garrett EH and Busta FF. 2003. Outbreaks associated with fresh produce incidence, growth, and survival of pathogens in fresh and fresh-cut produce. Compreh Rev Food Sci Food Saf 2(suppl) 78-141. 

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