The results showed gastroenteritis outbreaks per 1,000 cruises increased overall from 0.65 in 2001 to 5.46 in 2004. At the same time, ship environmental inspection scores were high, with an average of 95 on a 100-point scale.
Cramer attributes noroviruses to the increase. Cramer, medical epidemiologist with the Vessel Sanitation Program at the Centers for Disease Control and Prevention, says, "Since the introduction of more advanced laboratory techniques that can positively identify noroviruses, these viruses have increasingly been identified as associated with cruise ship outbreaks."
Dave Forney, chief of CDC's Vessel Sanitation Program, says, "We suspect that people are probably coming on board with the virus. On a cruise ship, people are out and about in very public areas, and so we have this depositing of the virus on various surfaces that then would be easily picked up by others."
In the study, researchers conclude, "This increase (in outbreaks) highlights the inability of environmental programs to fully predict and prevent risk factors common to person-to-person and fomite spread of the disease."
Fomites are inanimate objects like, dishes, toilet seats or doorknobs that may be contaminated with infectious organisms and help spread disease.
