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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Salmonella typhi is the causative agent of typhoid fever. The infective dose of S.typhi -
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The correct answer is  All Salmonella infections begin with ingestion of organisms, most commonly in contaminated food or water. The infectious dose is 103–106 colony-forming units.