The El Tor biotype of Vibrio cholerae O1, the dominant biotype responsible for the 7th pandemic, has been observed to acquire classical biotype characteristics including production of classical CT (cholera toxin). These are called:
- A O139 serogroup strains
- B Non-O1/Non-O139 environmental strains
- C Hybrid El Tor strains or Altered El Tor strains ✓
- D Ogawa serotype strains
Correct answer: C. Hybrid El Tor strains or Altered El Tor strains
Explanation
Since the early 2000s, 'Altered El Tor' or 'Hybrid El Tor' strains of V. cholerae O1 have emerged, which carry the classical biotype cholera toxin gene (ctxB classical) on the El Tor genomic background, and produce Hcp (Haitian-like) toxin. These hybrids cause more severe disease than conventional El Tor strains. V. cholerae O139 is a different serogroup, not a biotype. Ogawa and Inaba are serotypes of O1.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.