What is the Difference Between ETEC and EHEC?

ETEC (enterotoxigenic E. coli) and EHEC (enterohemorrhagic E. coli) are two major pathotypes of E. coli bacteria that cause gastrointestinal illnesses. The key differences between ETEC and EHEC include:

1. Infections: ETEC is the main cause of travelers' diarrhea, while EHEC is the main cause of bloody diarrhea.
2. Reservoirs of Infection: ETEC has a human reservoir of infection, while EHEC is a zoonotic disease with ruminants, especially cattle, as a natural reservoir.
3. Transmission: Both ETEC and EHEC infections are primarily acquired through the ingestion of contaminated food or water. However, ETEC is mainly transmitted via contaminated water, such as surface water and drinking water, while EHEC is transmitted through fecal contamination of food or water.
4. Pathogenesis: ETEC produces enterotoxins that cause watery diarrhea, while EHEC produces Shiga-like toxins that can cause damage to the lining of the intestine, leading to bloody diarrhea.
5. Infective Doses: The infective dose for ETEC ranges from 10^8 to 10^10 cells for adults, while vulnerable populations such as infants may be susceptible to infection at lower doses. In contrast, the infective dose for EHEC is much lower, with less than 50 to a few hundred organisms usually sufficient to lead to clinical signs.
6. Severity: Although both ETEC and EHEC infections show similar clinical pictures at the beginning, such as watery diarrhea leading to rapid dehydration, EHEC infections can potentially cause more severe complications, such as hemolytic uremic syndrome (HUS).

Comparative Table: ETEC vs EHEC

ETEC and EHEC are two main pathotypes of E. coli bacteria associated with gastrointestinal illness. ETEC is the main cause of travelers' diarrhea, while EHEC is the main cause of bloody diarrhea. Here is a table highlighting the differences between ETEC and EHEC:

Please note that the infectious dose for EHEC and the infectious dose for ETEC may vary. Both ETEC and EHEC infections can be acquired through ingestion of contaminated food or water. While ETEC primarily affects travelers and is mainly transmitted through water sources, EHEC is often associated with undercooked meat and contaminated vegetables, and can cause more severe complications.