LAS VEGAS -- Health officials say tainted water doesn't seem to be the cause behind hundreds of reports of gastrointestinal illness following the Rock `n' Roll Las Vegas Marathon.
Southern Nevada Health District epidemiologists say preliminary results of their investigation released Thursday are "largely inconsistent" with the hypothesis that hydrant water passed out during the race sickened runners.
Health officials say data also doesn't support the idea that out-of-town marathoners got sick because they aren't used to the desert climate, or that inexperienced runners were stricken more than veteran participants.
Authorities say no cause for the illness has been determined.
Runners speculated on Facebook that hydrant water poured into plastic-lined trash cans was contaminated.
Health officials surveyed about 1,000 of the 44,000 people who competed in the Dec. 4 race.