Diagnosis: Unknown
T01:C01 - S01:E01 - Tracking a Killer
Health officials investigate a Legionnaires' disease outbreak near Roanoke, Virginia, after patients contract the same strain of bacteria.
T01:C02 - S01:E02 - Tainted Blood
Health officials investigate a rare, fatal blood disorder spreading from Albuquerque to other states as they race to uncover its cause.
T01:C03 - S01:E03 - New Epidemic
Doctors investigate a deadly neurological outbreak in New York as mysterious illnesses in humans and zoo birds point to a mosquito-borne virus.
T01:C04 - S01:E04 - Invisible Threat
Minnesota health officials investigate a suspected food poisoning outbreak after a mother, her son and several others become seriously ill.
T01:C05 - S01:E05 - Summer Exposure
Health officials investigate an outbreak of rare bacterial disease on Martha's Vineyard after residents and landscapers become infected.
T01:C06 - S01:E06 - Unlikely Source
Health officials investigate suspected water contamination after a hospital in Walkerton, Ontario, sees a surge of patients with similar symptoms.
T01:C07 - S01:E07 - Island Fever
Health officials investigate a mysterious illness spreading through a Maui village as symptoms point to a potentially mosquito-borne virus.
T01:C08 - S01:E08 - Home Invasion
Investigators search for the cause of a family's chronic illnesses after doctors find similar symptoms among infants in comparable living conditions.
T01:C09 - S01:E09 - Sudden Death
Alberta health officials race to contain an outbreak of rare bacterial meningitis as cases rise and thousands of young people face exposure.
T01:C10 - S01:E10 - Toxic Exposure
Doctors investigate a series of life-threatening illnesses in Wisconsin as similar cases among women point to toxic shock syndrome.
T01:C11 - S01:E11 - Deadly Spores
Doctors investigate a deadly fungal outbreak on Vancouver Island after dozens of patients develop severe respiratory and neurological symptoms.
T01:C12 - S01:E12 - Dangerous Catch
Researchers develop troubling neurological symptoms and skin lesions, prompting an investigation into a possible link to their work with Pfiesteria.
T01:C13 - S01:E13 - Flesh Eater
Health officials investigate a deadly streptococcus outbreak in Texas as an aggressive strain causes severe illness and spreads beyond the state.