International health organizations are providing new information about a rare, virulent strain of deadly bacteria, as authorities try to pinpoint the source of the outbreak. Here are some facts:

E. coli and how it is transmitted; E. coli is an abbreviation for Escherichia, which is a large and diverse group of bacteria. Most strains are harmless, others can cause illness. Symptoms include stomach cramps, diarrhea and vomiting. The major source is cattle, but other animals, foods and liquids may spread contamination to people.

“Shiga toxin-producing” E. coli; This is a dangerous form of E. coli known by the acronym STEC. The best known strain of this STEC (also called (0157) was identified in 1982. Transmission and symptoms are similar to the most common form of E. coli.

EHEC; A very serious infection is enterohaemorrhagic E. coli known by the acronym EHEC. It produces toxins, known as verotoxins or Shiga-like toxins. It may lead to life threatening diseases such as hemolytic uremic syndrome, or HUS.

HUS; Scientists believe this is responsible for the European outbreak, originating from a potentially life threatening strain of STEC (0104). HUS afflicts the kidneys, blood and central nervous system.