German authorities on Thursday identified the northern city of Hamburg as the location where a sewage sample containing the wild form of the polio virus had been found, saying a task force had been established and more samples would be taken.The nation's main public health body, Robert Koch Institute, or RKI, told Reuters on Wednesday that the wastewater test at an unspecified German location was positive for the wild polio virus, in a setback for efforts to rid the world of the deadly disease.