Week 29 – July 18-22

2011 MOSQUITO REPORT: WEEK 29

Report based on data collected from traps deployed the week of July 18, 2011 through July 22, 2011. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. CURRENT MOSQUITO ACTIVITY/TREND

CDC Light Traps:
There was mixed host-seeking activity throughout Norfolk County for this week. About half of the towns reported lower than average activity. Foxboro, Medfield, Needham, and Stoughton had average levels of mosquito biting activity, whereas Medway, Millis, Norfolk, Walpole, Weymouth, and Wrentham experienced higher than average activity levels.

Gravid Traps:
Gravid mosquito activity was mixed this week as well. Avon, Braintree, Foxboro, Medfield, Norfolk, Randolph, and parts of Walpole had average gravid mosquito populations. Canton, Dedham, Dover, Franklin, Medway, Plainville, Quincy, parts of Sharon, Stoughton, parts of Walpole, and Weymouth collected higher than average gravid mosquitoes whereas the remaining towns reported lower than average numbers.

2. CURRENT PREDOMINANT SPECIES

CDC Light Traps:
Coquillettidia perturbans have made a return in abundance in Canton, Medway, Millis, Norfolk, Sharon, Walpole, Weymouth, and Wrentham. Culiseta melanura remain abundant in Sharon. Aedes vexans populations are higher than average in Canton, Franklin, Medway, Millis, and Weymouth; meanwhile Oc. taeniorhynchus has appeared in large numbers in Holbrook.

Gravid Traps:
Gravid Culex pipiens/restuans mosquito populations are mixed this week. Oc. japonicus numbers are about average for the week.

3. COMPARISON TO PREVIOUS SEASON

The week’s extremely hot weather conditions during trapping may have much to do with the mixed collections for host-seeking and gravid mosquitoes. New Co. perturbans populations are appearing in abundance as evidenced by parasitic mites on their bodies. Rainfall this week from localized thunderstorms may bring about higher numbers of Ae. vexans for next week.

4. WEATHER SUMMARY

This week was rather hot and humid. Other than some very light showers on Monday, the only rainfall occurred on Saturday morning with a line of strong to severe thunderstorms. The heaviest rainfall was along southern areas from Bellingham to Stoughton with amounts of ¼ to ¾ of an inch, while the remainder of the county received less than ¼ inch of rain.

Total weekly rainfall: 0.24 inches (-0.44 in.)
Total Monthly rainfall: 1.43 inches (-0.83 in.)
Total Yearly rainfall: 24.06 inches (+0.52 in.)

5. NUMBER OF REQUESTS FOR SERVICE

NCMCP received 4,738 calls year to date for service as of 7/22/11. NCMCP received 413 calls for service this week.

6. MCP/COMMISSION RESPONSE

NCMCP continues “area wide” ground ULV applications in high request areas and in areas where collection data indicate a need. Rain basin treatments continue with a concentration in urban areas where West Nile virus (WNV) has been collected historically. Rain basin treatments in the eastern areas where gravid traps are showing high levels of Culex have been prioritized. NCMCP is also prioritizing basin treatments adjacent to areas in Boston whereWest Nile virus has been identified. ULV applications have been conducted in these adjacent areas due to the high numbers of Culex collected in gravid traps. NCMCP continues some ground larviciding in coastal areas. Due to the positive WNV isolates in mosquitoes collected in Dedham and Quincy, NCMCP has conducted localized (focused) applications of both ULV and rain basin treatments. Boards of Health in both communities have stepped up public outreach using all available local media outlets.

Contact

144 Production Rd, Suite C

Walpole, MA 02081

Office: (781) 762-3681
Fax: (781) 769-6436