General Statements from the State Reclamation & Mosquito Control Board – 2015
Epi week #41, Oct. 11-17, 2015
With a hard frost coming in at the start of Epi Week 42, surveillance has been completed by all districts. As DPH noted in their own report, risk of arbovirus transmission is minimal following a hard frost, since nearly all mosquito activity will cease. Surveillance was also minimal this week, with only Central Mass. Mosquito Control Project submitting pools for testing; most Districts/Projects have now turned their attention to water management projects.
There was no arbovirus found this week. Arbovirus levels as a whole for the season were low, with only 1 EEEv+ mosquito pool found. According to DPH, the last time Massachusetts had only a single mosquito positive was in 2002 (in Tewksbury), and the last time we had a season with 0 EEEv+ mosquitoes was 1996. This is expected to be the final report of the 2015 season.
Epi Week 41 was another dry week for most of the state, except for the Cape and Islands and the southernmost tip of Bristol County, following thunderstorms that passed through on Oct. 16th, delivering an inch or more of rain in some locations. As noted above, a hard frost is expected to start off Epi Week 42, the earliest hard frost the state has seen in several years. Expect a return to above normal temperatures by the middle/late part of Epi Week 42, followed by a gradual cool down.
Epi week #40, Oct. 4-10, 2015
Mosquito activity is definitely ramping down for the season, as temperatures continue to drop. There were only 3 new WNV+ mosquito pools this week, bringing the total for the season to 164. Of the 3 pools, 2 were from Boston and in the Culex pipiens/restuans complex, and 1 was from Westborough (Worcester County) and was Culiseta melanura. No further EEEv activity was detected. Mosquito surveillance is minimal across the districts/projects, with no treatment operations currently in effect.
After a week with significant precipitation, the rainfall map is back to pale yellow, with accumulation across the state all well below an inch.
Expect a gradual cool down over Epi Week 41, until a cold snap hits over the weekend that will bring daytime highs down to the low 40s. If winds go calm in the interior of the state, we could easily see many locations bottom out with upper 20s for overnight lows, which would guarantee a killing freeze. Even if the winds do not go calm, temperatures will still average 30-34F, which is plenty low enough for our first widespread frost. That said, we will not “lock-in” to this cold and should return to above normal temperatures by the middle/late part of Epi Week 42.