Revised Massachusetts state guidelines now allow officials to consider aerial insecticide spraying as soon as an area is deemed at "high risk" for EEE instead of the "critical" level required before. The guidelines make it easier to reach the "high risk" category, by requiring that only one sample of mammal biting mosquitoes carrying EEE be found in an area instead of two. The revisions have dropped the threshold for "critical risk," as well.
New EEE protection guidelines
Guidelines now allow officials to consider aerial insecticide spraying as soon as an area is deemed at "high risk" for EEE instead of the "critical" level required before.
The revisions also allow for more targeted aerial spraying instead of the sweeping, regional sprays performed in 2006 and 2010.
Since EEE was first recorded in Massachusetts in 1938, the mosquito-borne virus has caused fewer than 100 confirmed human cases, and killed about half of them, according to the Massachusetts Department of Public Health. More than 60 percent of Massachusetts' cases have been in Plymouth and Norfolk counties.
Human EEE cases in Massachusetts have usually occurred in outbreaks lasting two to three years, striking about 10-20 years apart, according to DPH.
But the pattern in more recent years points to an apparent change in the risk cycle, said Kevin Cranston, director of DPH's Bureau of Infectious Disease.
The number of cases recorded during outbreaks has dropped significantly, but the average time between these outbreaks has shortened, according to a report by the panel. Years with more than one human case of EEE are tending to hit more often, and there is an increased probability in any given year that at least one person will be infected.
The new regulations in Massachusetts for aerial insecticide spraying for mosquitoes will help protect both equines and humans from Eastern equine encephalitis.
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