The control of VTEC in the animal reservoir

摘要: Abstract A great diversity of VTECs exist but only in the case Escherichia coli O157:H7, a common human foodborne pathogen, has sufficient research been done to allow generalizations about ecology. The key features are as follows: lack host specificity such that indistinguishable isolates can be found variety species; near-ubiquitous distribution cattle (and perhaps other ruminant) farms; transient residence gastrointestinal flora individual animals is not associated with clinical disease; temporal clustering at population level most fecal shedding confined sharp bursts high percentage separated by much longer periods very low prevalence; higher prevalence young comparison older ones; floral disturbance caused transit, feed changes or antimicrobial dosing; and markedly during warm months. Molecular epidemiological studies E. O157:H7 have demonstrated subtypes organism persist on farms for years, thus supporting conclusion represent reservoir. Yet farms, often environmental niches species animals; thus, it completely clear themselves New periodically observed particular hundreds kilometers even absence any obvious animal movements between them. number farm does appear qualitatively correlated (e.g., purchases) into farm. Commercial feeds sometimes contaminated seems likely an important route dissemination this agent VTEC. Mixed collected from feeding troughs commonly positive watering troughs, water means infection. Environmental replication sediments occurs may account Since remain infective least 6 months trough sediments, niche where survives when cannot detected cattle, especially cold Traditional controlling infectious agents, eradication test removal carrier animals, do feasible VTECs. Nevertheless, certain management practices—especially those related maintenance multiplication water—may provide practical substantially reduce these agents arriving slaughter plants.