A woman (Jane McNeill) shows the signs of a biological epidemic in Barry Levinson's found-footage thriller "The Bay."

Grade • B

DVD • There are shocks aplenty in the horror-thriller “The Bay,” but the biggest surprise is that it’s directed by Barry Levinson, the Hollywood veteran of “Rain Man,” “Diner” and “Wag the Dog.”

On a July 4th weekend in a Chesapeake Bay community, the usual patriotic festivities are cut short when a flesh-eating parasite, fed by nearby pollution, starts spreading among the townspeople. Panic, fear and violence soon take over the town, while Centers for Disease Control officials try to make sense of it all.

Adopting the new tricks of the found-footage genre — including cellphones, home video, surveillance cameras, Skype and TV reports — Levinson never lets the gimmicks dominate the terrifying and well-paced story.