<prompt> Which one of the following is a rickettsial diseaseWeils diseaseRocky mountain feverRelapsing feverPontaic fever  <response>: Rocky mountain spotted fever is caused by R.ricketsii.vector is dermacentar andersonii it is prevalent in noh america and South America. It is the most serious type of spotted fever Ref: AnanthNarayan and panikers 10th edition 