Epi Week #25 - 2014 General Statements
Arbovirus testing has begun for 2014, with mosquito control projects/districts and the state laboratory starting the week to week monitoring for both West Nile Virus (WNV) and Eastern Equine Encephalitis (EEEv). As is typical with the first report of the season, no arbovirus has been detected yet. However, because of last summer’s WNV and EEEv activity, we can anticipate the first mosquito pool detections within the next few weeks.
Several of the Mosquito Control Districts/Projects (MCDs/MCPs) noted that cool spring temperatures and lack of precipitation has led to lower than average mosquito populations compared to previous years. The Mass. Dept. of Public Health (DPH) also indicated lower than average collections of Culiseta melanura (a primary carrier of EEEv) from their long-term traps. While temperatures have certainly ramped up over the past couple of weeks, precipitation remains below normal for much for the state, and that’s typically good news for us and bad news for mosquitoes.
MCDs/MCPs continued larviciding of catch basins to combat increasing populations of Culex spp. Several also reported ULV application of adulticides, either for individual resident requests or wide-area spraying.
The most abundant species of mosquitoes so far this season have been Culex pipiens/restuans, Culiseta melanura, and Ochlerotatus canadensis. Bristol County reported a single Aedes albopictus (Asian Tiger Mosquito) was collected this week – we will continue to watch this situation closely this season given the potential for that species to become established in Mass. and its ability to carry Dengue fever and Chikungunya virus.
Weather
Looking back to early 2014, March was below average in both snowfall and temperature, with average temperature nearly 5’F below average for the month. In contrast, April temperatures returned to nearly normal, with precipitation just slightly below average. May temperatures were actually slightly above average, though it felt cooler because we ended the month with a dramatic cold spell. May precipitation was slightly below average. June precipitation continued to be below average for most regions, with Epi Week 25 producing no more than .65 inches of rain anywhere in the state.
