PAMPLONA, Spain — Two Americans and a Briton were gored and eight others injured Tuesday as thousands of daredevils dashed alongside fighting bulls through the streets of this northern Spanish city on the first bull run of the San Fermin festival, organizers said. The San Fermin press office said a 38-year-old American identified only by his initials, M.W.O., was gored in the armpit and a 27-year-old Californian identified by the initials D.M.O.