David Duchovny

Dr. Ira Kane

Julianne Moore

Dr. Allison Reed, CDC

Orlando Jones

Prof. Harry Phineas Block

Seann William Scott

Wayne Grey

Ted Levine

General Russell Woodman

Ty Burrell

Colonel Flemming

Ethan Suplee

Deke

Michael Bower

Danny

Dan Aykroyd

Governor Lewis

Gregory Itzin

Cartwright

Pat Kilbane

Officer Johnson

Sarah Silverman

Denise

Michelle Wolff

Carla

Katharine Towne

Nadine

Stephanie Hodge

Jill Mason

John Cho

Student

Steven Gilborn

Judge Guilder

Wayne Duvall

Dr. Paulson

Kyle Gass

Officer Drake

Jerry Trainor

Tommy

Jennifer Savidge

Clare

Wendy Braun

Nurse Tate

Michael Chapman

Sheriff Long

Mary Pat Gleason

Customer

Andrew Bowen

Road Worker

Chris Wylde

Student

Tom Woodruff Jr.

Lead Primate Creature (uncredited)

Ashley Clark

Lt. Cryer