Three types of outbreaks were used, each representing various types of naturally occurring events: log normal, a rapidly increasing outbreak; inverted log normal, a slowly starting outbreak; and a single-day spike.
Increased outbreaks have been linked to a number of factors from decreased predation, increased nutrient run-off, increased salinity, and increased water temperatures.
The emergence of new norovirus GII.4 variants resulted in an increased norovirus outbreak activity in the following season in a unique biannual pattern in Alberta over an eight year period.
Ron Klain, the Ebola czar under then-President Barack Obama, disagrees with that last characterization of a "perfect storm". While Ebola has never been fought in a war zone before, he argues that this is the "new normal," not a one-off situation, in an era of increasing outbreaks of the highest risk.
Re "Climate Change Isn't a Culprit in Increasing Outbreaks, Study Finds" (Global Update, Aug. 30): You report a study indicating that warmer oceans do not increase blooms in plankton and consequently the proliferation of the bacterium Vibrio cholerae.
Measles, a disease declared eliminated in the United States 15 years ago, is posing a renewed health threat with increasing outbreaks in the last two years.
Lopman et al found that the number of beds on a ward and elderly care wards was related to an increased hazard of outbreaks occurring.
The proportion of GII.4 Sydney outbreaks in the states with an increased cumulative number of outbreaks in 2012 2013 was not significantly different from the proportion in those states without an increased number of outbreaks (61% vs. 67%, respectively; p = 0.27).
Problems in defining epidemics exist as well, since most reports lack clear or internationally recognized criteria; we had to accept the perception of an increased incidence that prompted outbreak reports.
Finally, increased flooding could result in flooded sewage treatment plants and an increased risk of cryptosporidiosis outbreaks (EEA, 2007).
