Laurence Fishburne at a "Contagion" photocall during the 68th Venice International Film Festival. (Sept. 4, 2011)

*The killer virus thriller “Contagion,” which stars Lawrence Fishburne as the head of the Center for Disease Control trying to stop a pandemic, took in $23.1 million to easily win the weekend box office.

The Warner Bros. film bumps “The Help” off its three-week perch to No. 2. The Viola Davis and Octavia Spencer movie held the No. 1 spot for 25 days in a row—the best showing since “The Sixth Sense” (35 days)–but it still scored a weekend take of $8.7 million for a new domestic total of $137.1 million.

The performance of “The Help” and Steven Soderbergh’s “Contagion” is a notable win for Participant Media, which co-financed and co-produced both titles (“Contagion” with Warner Bros., and “The Help” with DreamWorks).

The socially minded production company–run by CEO Jim Berk and president Ricky Strauss–was founded by Jeff Skoll, who runs a separate foundation focusing on the five biggest threats facing the globe–one of them being pandemics.

“Contagion,” also starring Matt Damon, Gwyneth Paltrow, Marion Cotillard, Jude Law, Kate Winslet and Bryan Cranston, is about as a team of CDC doctors, world health officials and citizens caught up in trying to stop a worldwide viral outbreak. The $60 million pic received a B- CinemaScore, with more than 80% of the audience over the age of 25.

Meanwhile, Sony’s Zoe Saldana action pic Colombiana came in at No. 5, grossing an estimated $4 million for a cume of $29.8 million in its third weekend.

DOMESTIC BOX OFFICE (Sept. 9-11)

1. Contagion (Warner Bros., 3,222): $23.1 Million

2. The Help (Disney, 2,935): $8.7 Million

3. Warrior (Lionsgate, 1869): $5.6 Million

4. The Debt (Focus, 1,872): $4.9 Million

5. Colombiana (Sony, 2,354): $4 Million

6. Rise of the Planet of the Apes (Fox, 2,887): $3.9 Million

7. Shark Night 3D (Relativity Media, 2,848): $3.5 Million

8. Apollo 18 (Weinstein Co., 3,330): $2.9 Million

9. Our Idiot Brother (Weinstein Co., 2,396): $2.8 Million

10. Spy Kids: All the Time in the World in 4D (Weinstein Co., 2,544): $2.5 Million