Summary of Program

Since the first identification of West Nile Virus in Manchester in 2000, the Manchester Health Department has actively engaged in arboviral surveillance and control. The program aims to minimize residents' risk of exposure to mosquito-borne diseases. Continued surveillance, control, and public education are essential for protecting public health in Manchester.

Arboviruses, short for arthropod-borne viruses, are illnesses transmitted to humans by the bites of mosquitoes and ticks. Manchester’s Arboviral Surveillance Program primarily focuses on monitoring mosquito-borne arboviruses. 

In New Hampshire, there are three arboviruses of concern: West Nile Virus (WNV), Eastern Equine Encephalitis (EEE), and Jamestown Canyon Virus (JCV). WNV, EEE, and JCV can be spread to humans through the bite of an infected mosquito. 

Surveillance

Manchester's Arboviral Serveillance Program includes mosquito and human serveillance components:

1. Mosquito Surveillance: From July to mid-October, mosquito traps are routinely deployed at various locations across the city. Mosquitoes are collected, identified by species, and submitted to the NH State Public Health Lab for WNV, EEE, and JCV testing. Positive results of this testing can indicate an increased risk to humans.
2. Human Surveillance: The Manchester Health Department collaborates with healthcare providers and the New Hampshire Department of Health and Human Services to identify and follow up with patients infected with WNV, EEE, and JCV to understand the infection's source and spread.

Please visit the New Hampshire Department of Health and Human Services Mosquito-Borne Illnesses webpage to view routine arbovirus test results and the NH Arboviral Risk Map. Results and risk levels are updated weekly throughout the surveillance season.

Spraying

The Manchester Health Department works closely with the New Hampshire Department of Health and Human Services (DHHS) to evaluate possible ongoing mosquito-borne disease transmission in and around the community.

When sufficient data indicates an increased public health risk, the decision to spray and apply pesticides at various city-owned properties is made. In partnership with our contracted pesticide applicator, the Manchester Health Department holds a special permit from the New Hampshire Department of Agriculture to spray for mosquito control during public health emergencies. Before spraying, the public is notified of the date, time, and location of spraying in accordance with special permit requirements. Additionally, information about the pesticides to be used is made available through public notification.

Please review the New Hampshire Arboviral Illness Surveillance, Prevention, and Response Plan for more information on arboviral surveillance response. 

Mosquito Spraying

Currently, there is no scheduled spraying in the City of Manchester. Below are insecticides commonly used when spraying:

• crosscheck-insecticide-label.pdf
• crosscheckplussds.pdf
• merus3_0.pdf
• merus3_0-sds.pdf

Control Measures

Mosquitoes lay their eggs in stagnant or standing water. Eliminating standing water and limiting mosquito breeding opportunities is the primary strategy for preventing disease transmission. In 2001, Manchester adopted the ordinance below to combat mosquito breeding conditions:

91.51 DUTY TO MAINTAIN PREMISES FREE OF MOSQUITO BREEDING CONDITIONS.

   The owner or person in control of any piece of property shall at all times maintain the premises free of any barrel, tire, tub, swimming pool, ornamental pool, or any other artificial water receptacle, or shall treat and maintain such receptacle in a manner that prevents the breeding of mosquitoes.

Below are steps that property owners can take to reduce mosquito breeding:

1. Eliminate Standing Water: 
   • Empty and clean birdbaths, gutters, and pet water dishes regularly
   • Turn over items such as wheelbarrows and plastic wading pools when not in use
   • Remove and discard rimless tires, buckets, cans, and other containers capable of holding water
   • Drill holes in the bottom of containers capable of holding water
2. Proper Maintenance of Swimming Pools and Ponds:
   • Ensure swimming pools are maintained and treated with appropriate chemicals
   • Cover pools when not in use and ensure the cover does not collect water on top
   • Aerate or stock ornamental ponds with mosquito-eating fish, such as guppies or goldfish
3. Landscape Management:
   • Trim tall grass and bushes to allow air to circulate through plants
   • Remove excess vegetation and organic debris from around water sources
4. Rainwater Management:
   • Ensure rainwater drainage systems are functioning correctly to avoid water accumulation
   • Use rain barrels with tight-fitting lids or mosquito screens
5. Install Screens and Barriers:
   • Use fine mesh screens on windows and doors to prevent mosquitoes from entering buildings
   • Repair holes in screens on windows and doors
6. Regular Inspections and Maintenance:
   • Regularly inspect your property to identify and address potential mosquito breeding sites
   • Ensure septic tanks are properly sealed and maintained to prevent mosquito entry
   • Remind and help neighbors maintain their property free of mosquito breeding conditions. Preventing mosquito-borne illnesses is a community effort!
7. Use of Larvicides:
   1. Apply larvicides to standing water that cannot be eliminated to kill mosquito larvae before they become adults. Larvicides are particularly useful in ponds, ditches, and rain barrels
      • Bacillus thuringiensis israelensis (Bti): Bti produces toxins that are deadly to mosquito larvae. 

Implementing these methods can significantly reduce mosquito breeding and minimize the risk of mosquito-borne illnesses in the community. 

Bite Prevention

To reduce your risk of being bitten by mosquitoes and contracting West Nile Virus or Eastern Equine Encephalitis:

• If you are outside during the evening, nighttime, and dawn hours, wear protective clothing such as long pants, long-sleeved shirts, a hat, and socks.
• If you are outside during the evening, nighttime, and dawn hours, consider using an insect repellent containing no more than 30% DEET (N, N-diethyl-meta-toluamide). Repellents containing Picaridin, lemon eucalyptus oil, or IR3535 have also been deemed effective. 
• Remember always to use repellants in accordance with the manufacturer’s directions.
• Children should not apply DEET to themselves. Since repellents may irritate the eyes and mouth, avoid applying repellent to children's hands.

For additional information on mosquito-borne viruses, prevention guidelines, and risk levels, please visit the New Hampshire Department of Health and Human Services Mosquito-Borne Illnesses webpage.