Public Health IPM
Insects, Mosquitos & Ticks in Public Health
Mosquito-Borne Disease Risk in New Hampshire - Oct 6, 2015
Dr. Alan Eaton, UNH Cooperative Extension
This week we learned of our second positive indicator for Eastern Equine Encephalitis this year: another batch of Culiseta melanura mosquitoes tested positive, this time from Candia. Both Candia and Newton (site of last week’s positive mosquito batch) are places where historically the risk of EEE has been elevated in our state. Other positive EEE indicators in New England include positive mosquito batches in York County Maine, and Franklin County, Vermont.
We had no additional West Nile Virus indicators announced this week.
So this raises the disease risk slightly for Rockingham County, an area that has experienced elevated EEE risk in the past. Culiseta melanura is a bird-biting species, so this shows the virus is being spread among birds there now. The risk for WNV stays roughly the same as last week for us. Last week’s announcement of a WNV-positive bird from Holderness points out that the risk is not completely restricted to those towns with positive mosquito batches (in Cheshire, Hillsborough and Rockingham Counties). Additionally, WNV-positive mosquito batches have now been found in every county of Massachusetts, and in every county of Vermont except Orange, Caledonia and Essex. At least one human case was announced from Cumberland County, ME. When a hard frost kills off the adult mosquitoes, the risk should plummet. A light frost is insufficient to do this.
Protecting yourself from mosquito bites is your best defense from acquiring one of these diseases. That includes minimizing going in areas with lots of mosquitoes (esp within an hour or two of dusk), wearing clothing that exposes little skin, and using repellants if you are outdoors in mosquito-prone places. Read my publication on repellants.
Mosquito-Borne Disease Risk in New Hampshire - Sept 30, 2015
This week we learned of our very first positive indicator for Eastern Equine Encephalitis this year: a batch of Culiseta melanura mosquitoes from Newton that tested positive. The only other positive indicators anywhere in New England were announced recently: positive mosquito batches in York County Maine, and Franklin County, Vermont.
We had one additional West Nile Virus indicator announced this week: a raven from Holderness.
So this raises the risk slightly for Rockingham County, an area that has experienced elevated EEE risk in the past. C. melanura is a bird-biting species, so this shows the virus is being spread among birds there now. The risk for WNV stays about the same, but the discovery of a WNV-positive bird from Holderness points out that the risk is not completely restricted to those towns with positive mosquito batches. When a hard frost kills off the adult mosquitoes, the risk should dramatically drop.
Mosquito-Borne Disease Update - Sept 25, 2015
The risk of acquiring a mosquito-spread disease in New Hampshire is unusually low for this time of year. This week we learned that two additional batches of mosquitoes tested positive for West Nile Virus. One was a batch of Culiseta morsitans from East Kingston. That species is a mixed feeder, meaning that it sometimes bites mammals. The second was a batch of Aedes vexans from Keene. That species mostly bites mammals. So now there is a slightly elevated risk of acquiring WNV in three areas that we know of… the areas around East Kingston, Manchester and Keene.
So far there are still no positive indicators for Eastern Equine Encephalitis in New Hampshire. Positive mosquito batches have now been detected in York County, ME and Franklin Co, Vermont.
New Hampshire Mosquito-Borne Virus Situation - Sept 9, 2015
As of today, New Hampshire has had no positive indicators of mosquito-borne diseases this year. That includes mosquito and bird testing, veterinary cases or human cases. In bad years for West Nile Virus or Eastern Equine Encephalitis, we would have found positive mosquito batches, and several veterinary or human cases by now. The risk is always highest in September, and sometimes it extends into early October if we don’t get a good, killing frost until then. But I am pleased to note that no EEE positives have been reported anywhere in New England.
For West Nile Virus, there have been no human cases so far, but positive mosquito batches have turned up in several states: Vermont: Addison Co, Franklin Co, Rutland Co, Washington Co, Windham Co, Windsor Co. Massachusetts: Barnstable, Berkshire, Bristol, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester Counties. Connecticut: Fairfield, Hartford, New Haven, New London and Middlesex Counties. Rhode Island: Washington Co. Maine: No positives.
So, I am pleased to report that overall the risk in New Hampshire is low now. That could change. During periods of elevated risk, you affect your risk by where you go, what time of day you are active, how much exposed skin you have, and whether or not you use insect repellant.
New Hampshire Tick-Borne Disease Prevention Plan
This plan was unveiled (if that’s the correct word…) April 14th, 2015. The lead author is Dr. Abigail Matthewson, of the NH Department of Health and Human Services, but several of us in various state agencies participated in the planning, assembling information, and writing. It covers all human tick-borne diseases in New Hampshire, describes their symptoms & etiology, and goes over the various options to prevent becoming a victim. There are dozens of links to useful information, for people who really want a really thorough coverage of the subject. To learn more about Lyme and other tick borne diseases, click here. -Dr. Alan Eaton, Entomologist, UNH Cooperative Extension
Blacklegged Ticks in New Hampshire, Updated Map 2014
This map is the result of 25 years of active and passive surveillance on blacklegged tick (BLT) in New Hampshire. In the beginning, there were just three published records of this species in New Hampshire. This map compiles over 700 records, through late November 2013.
The NH Division of Health & Human Services has information and maps on Lyme disease and blacklegged tick.
Ticks can transmit several human diseases, and New Hampshire is home to many species of ticks. Learn what ticks look like, how they live, the diseases they spread, how to manage tick problems, and how to protect yourself from tick-borne diseases.
The NH Division of Health & Human Services has information & maps on mosquito-spread diseases in NH.
Eastern Equine Encephalitis (EEE) is a disease that is transmitted by mosquitos. Learn about Eastern Equine Encephalitis (EEE) and how it spreads, what types of mosquitos transmit EEE, and how to protect yourself from this disease.
Insect repellents can help you protect yourself from insect-borne diseases. Learn about the various types of insect repellents available and their efficacy.