<prompt> Most virulent variety of shigellosis is caused by:S. dysentriaeS. sonneiS. flexneriS. boydii  <response>: Ans. is a i.e., Shigella dysenteriaeRef: Ananthanarayan, 8the, p. 286 and 9the, p. 2851Complications are most often seen in infection with Sh. dysenteriae type I and include arthritis, toxic neuritis, conjunctivitis, parotitis and in children, intussusception. HUS may occur in severe cases. 