The DNREC Mosquito Control section’s woodland pools spray campaign targets larval (immature) mosquitoes before they can emerge as biting insects that torment Delawareans and visitors alike later in spring and summer. /DNREC photo

Spring Campaign to Reduce Numbers of Year’s First Biting Mosquitoes

The Delaware Department of Natural Resources and Environmental Control will begin its annual spraying of spring woodland pools to control aquatic immature (larval) mosquitoes as early as Friday, March 15, weather permitting. The spring spray campaign by DNREC’s Mosquito Control section will begin in southern Sussex County, then expand into Kent and New Castle counties over the next several weeks. Controlling early-season woodland pool larval mosquitoes limits the emergence of biting adult mosquitoes later in the spring.

Up to 10,000 acres of wet woodlands near select populated areas will be treated with a helicopter applying the bacteria-derived insecticide Bti. As with all insecticides used by the Mosquito Control section within the DNREC Division of Fish and Wildlife, Bti has been determined by the U.S. Environmental Protection Agency to pose no unreasonable risks to human health, wildlife or the environment when applied in accordance with product label instructions as required by federal law.

The spring woodland mosquito larvae spraying campaign marks the beginning of Delaware’s mosquito control season – which in most years continues until late October or early November. Starting in April, Mosquito Control section activities will expand to larval and adult saltmarsh mosquitoes, other freshwater mosquitoes, and urban and suburban container-breeding mosquitoes to manage mosquito populations for improving the state’s quality of life and to protect public health.

Locations and times for scheduled mosquito spraying activity in the state can be obtained by calling toll-free 800-338-8181. Mosquito spraying announcements can also be received by email, text or voicemail by subscribing to Mosquito Control’s Spray Zone Notification System at de.gov/mosquitospray.

To request local mosquito control service, call a Mosquito Control section field office:

• Glasgow Office, 302-836-2555, serving New Castle County and the northern half of Kent County, including Dover.
• Milford Office, 302-422-1512, serving the southern half of Kent County south of Dover and all of Sussex County.

For more information on DNREC’s mosquito control efforts in Delaware, visit de.gov/mosquito.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. The DNREC Division of Fish and Wildlife conserves and manages Delaware’s fish and wildlife and their habitats, and provides fishing, hunting, wildlife viewing and boating access on nearly 68,000 acres of public land owned or managed by the Division of Fish and Wildlife. For more information, visit the website and connect with @DelawareDNREC on Facebook, Instagram, X (formerly known as Twitter) or LinkedIn.

Media contacts: Michael Globetti, michael.globetti@delaware.gov; Nikki Lavoie, nikki.lavoie@delaware.gov

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No Human Cases of WNV Reported to Date in State; Equine
Owners Urged by Department of Agriculture to Vaccinate Animals

West Nile Virus (WNV) has been detected in Delaware the first time for 2023 in a sentinel chicken, the Delaware Department of Natural Resources and Environmental Control announced today. This initial finding was from a sentinel chicken station near Wilmington sampled on July 31 by the DNREC Mosquito Control Section, and then tested and reported virus positive by the Delaware Public Health Laboratory on Aug. 4. While there have been no reported WNV cases in humans this year in the state, Delawareans are reminded that the possibility of contracting mosquito-transmitted diseases, including WNV and eastern equine encephalitis (EEE), will continue until colder autumn temperatures arrive in mid-October or later.

Blood samples are collected by the DNREC Mosquito Control section each week from early July into October from the state’s outdoor-caged sentinel chickens that are humanely housed and handled at 20 monitoring stations statewide. The blood samples are tested for WNV and EEE antibodies by the Delaware Public Health Laboratory. Sentinel chickens bitten by mosquitoes carrying WNV or EEE develop antibodies to these diseases but are otherwise unaffected. Mosquitoes can transmit both WNV and EEE to humans and horses.

Most people infected with WNV do not develop symptoms, but about 20% can develop a mild illness, including fever, body and muscle aches, headache, nausea, vomiting, and rash symptoms. A small number of people can develop serious illness involving neurological problems, paralysis, and possibly death. The Division of Public Health Disease Prevention & Control Section reports that Delaware had one confirmed case of invasive WNV in 2022, and none so far this year. EEE is not as prevalent as WNV but can present more severe symptoms in humans and horses.

The public is reminded to take common-sense precautions to avoid mosquito bites, including wearing light-colored clothing of long-sleeved shirts and long pants when outdoors in mosquito-prone areas; applying insect repellent containing 10 to 30% diethyltoluamide (DEET) in accordance with label instructions; and avoiding mosquito-infested areas and at times of peak mosquito activity around dusk, dawn and at night.

According to the Delaware Department of Agriculture (DDA), there were no equine cases of WNV or EEE in 2022. The State Veterinarian urges horse owners to contact their veterinarians to vaccinate horses and other equines against WNV and EEE. Both vaccines are highly effective in minimizing disease and may be the reason why Delaware had no equine cases in 2022. Horses that have been vaccinated in the past will need an annual booster shot. Neither disease has a specific drug treatment, and infections in horses are fatal in 70% to 90% of EEE cases and 30% of WNV cases.

Spraying to reduce mosquito populations in areas where WNV or EEE is detected may be initiated by the DNREC Mosquito Control Section as warranted, based on factors to include mosquito population levels and mosquito species present in affected areas. To reduce mosquito-breeding habitat and chances of disease transmission, residents should drain or remove outdoor items that collect water, such as discarded buckets or containers, uncovered trashcans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in boat tarps, clogged rain gutters, corrugated downspout extenders, and unused swimming pools.

Horse owners can take several additional steps in the barn and around the farm to help protect horses from mosquito bites. Horses should be kept inside at dawn and dusk, peak hours for mosquito activity. Topical insect repellents labeled for use on horses may be applied. Wind generated by fans installed in horse stalls can also help deter mosquitoes. Water troughs or buckets should be emptied, cleaned, and refilled every 2-3 days to remove mosquito eggs or larvae.

• For mosquito biology/ecology and control, contact the DNREC Mosquito Control section office in Dover at 302-739-9917.
  • For requests for mosquito relief in upstate areas from Dover north, contact Mosquito Control’s Glasgow field office at 302-836-2555.
  • For requests for mosquito relief in downstate areas south of Dover, contact Mosquito Control’s Milford field office at 302-422-1512.
• For animal health questions, contact the Delaware Department of Agriculture’s Poultry and Animal Health Section at 302-698-4500.
• To report suspected cases of human WNV, call the Delaware Division of Public Health Office of Infectious Disease Epidemiology toll-free at 888-295-5156.
  • For more information on West Nile virus or eastern equine encephalitis, visit cdc.gov/ncidod/dvbid/westnile/index.htm.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. The DNREC Division of Fish and Wildlife conserves and manages Delaware’s fish and wildlife and their habitats, and provides fishing, hunting, wildlife viewing and boating access on nearly 68,000 acres of public land owned or managed by the Division of Fish and Wildlife. For more information, visit the website and connect with @DelawareDNREC on Facebook, Instagram,  Twitter or LinkedIn.

Media contacts: Michael Globetti, michael.globetti@delaware.gov; Nikki Lavoie, nikki.lavoie@delaware.gov
DDA: Stacey Hofmann, stacey.hofmann@delaware.gov

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DNREC Mosquito Control Section will begin aerial spraying of woodland pools this week to limit the emergence of biting adult mosquitoes later in the spring. /DNREC photo

Spring Campaign Will Reduce Numbers of Year’s First Biting Mosquitoes

The Delaware Department of Natural Resources and Environmental Control will begin annual spraying of spring woodland pools to control aquatic immature (larval) mosquitoes on Wednesday, March 16, weather permitting. Spraying by DNREC’s Mosquito Control section will begin in southern Sussex County, then expand into Kent and New Castle counties over the next several weeks. Controlling early-season woodland pool larval mosquitoes limits the emergence of biting adult mosquitoes later in the spring.

Up to 10,000 acres of wet woodlands near select populated areas will be treated with a helicopter applying the bacteria-derived insecticide Bti. As with all insecticides used by the Mosquito Control section within the DNREC Division of Fish and Wildlife, Bti has been determined by the U.S. Environmental Protection Agency to pose no unreasonable risks to human health, wildlife or the environment when applied in accordance with product label instructions as required by federal law.

The spring woodland mosquito larvae spraying campaign marks the beginning of Delaware’s mosquito control season, which in most years continues until late October or early November. Control activities will be expanded starting in mid-April to larval and adult saltmarsh mosquitoes, other freshwater mosquitoes, and urban and suburban container-breeding mosquitoes to manage mosquito populations for improving the state’s quality of life and to protect public health.
Locations and times for scheduled mosquito spraying activity can be obtained by calling toll-free 800-338-8181. Mosquito spraying announcements can also be received by email, text or voicemail by subscribing to Mosquito Control’s Spray Zone Notification System at de.gov/mosquitospray.

To request local mosquito control service, please call the following Mosquito Control field offices

• Glasgow Office, 302-836-2555, serving New Castle County and the northern half of Kent County, including Dover.
• Milford Office, 302-422-1512, serving the southern half of Kent County south of Dover and all of Sussex County.
  For more information on mosquito control in Delaware, call the Mosquito Control Dover office at 302-739-9917.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities, and educates Delawareans about the environment. The DNREC Division of Fish and Wildlife conserves and manages Delaware’s fish and wildlife and their habitats, and provides fishing, hunting, wildlife viewing and boating access on nearly 68,000 acres of public land. For more information, visit the website and connect with @DelawareDNREC on Facebook, Twitter or LinkedIn.

Media Contacts: Michael Globetti, michael.globetti@delaware.gov; Nikki Lavoie, nikki.lavoie@delaware.gov

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DOVER (Oct. 8, 2021) – The Division of Public Health (DPH) announced today that a 79-year-old Sussex County woman has become infected with West Nile Virus (WNV), the state’s second case of human WNV in 2021. An epidemiological investigation is currently ongoing to confirm any travel history or sources that could have led to transmission. To protect the patient’s privacy, no more information will be provided on the individual at this time.

“As mosquito season continues through the fall months, it is important for everyone to take proper precautions when going outdoors in an environment where mosquitoes are prevalent,” said DPH Director Dr. Karyl Rattay. “Wearing insect repellent and wearing light-colored, long-sleeved shirts and pants are easy measures to take that can protect against this serious and sometimes deadly virus.”

The mosquitoes that cause WNV bite primarily from dusk (evening) to dawn (morning). However, other mosquitoes that cause diseases such as chikungunya, dengue fever, and Zika can bite during the day. It is important to protect yourself by wearing insect repellent whenever you go outdoors.

WNV is a mosquito-borne illness that can cause serious health problems. WNV is transmitted by mosquitoes, generally in summer and fall, with a peak period for disease transmissions from mid-August to mid-October. Nearly 80 percent of people infected with WNV will not become ill. While only a little less than 20 percent of those infected with the virus will develop West Nile fever with mild symptoms (fever, headache, body aches, a skin rash on the chest or back and swollen lymph glands), one in 150 people infected will develop severe infection (West Nile encephalitis or meningitis).

Symptoms of severe WNV infection include headache, high fever, stiff neck, and/or tremors and muscle weakness. The elderly and those with weakened immune systems are most at risk. Anyone who experiences any of these severe symptoms should seek medical help immediately. Symptoms may progress to stupor, disorientation, coma, convulsions, paralysis and possibly death.

In addition, the Office of the State Veterinarian has announced a confirmed case of West Nile Virus (WNV) in a horse. The infected horse was a 3-year-old Standardbred gelding residing in Kent County. The horse began showing signs of weakness in the hind limbs, with fever and respiratory signs on Oct. 1. The gelding lost the ability to stand and was therefore euthanized on Oct. 5. Samples were submitted to the Delaware Public Health Laboratory on Oct. 6, which confirmed the diagnosis of WNV on Oct. 7. The affected horse was not currently vaccinated against WNV.

West Nile Virus and Eastern Equine Encephalitis (EEE) are diseases transmitted to horses via the bites of mosquitoes. Humans can also be infected with WNV and EEE, but transmission requires a mosquito bite, and the virus cannot be directly transmitted between horses, or between horses and people. Signs of infection in horses include fever (although not always with WNV), anorexia, head pressing, depression or personality change, wobbling or staggering, weakness, blindness, convulsions, muscle spasms in the head and neck, or hind-limb weakness. If owners notice any of these signs in their horses, they should contact their veterinarian immediately.

“It is essential that owners of horses and other equines work with their veterinarian to set up a routine vaccination protocol to help prevent West Nile Virus and Eastern Equine Encephalitis,” said Dr. Karen Lopez, Deputy State Veterinarian. “Unfortunately, neither disease has a specific drug treatment. Eastern Equine Encephalitis infections are fatal in 70 to 90 percent of the cases, and West Nile Virus is fatal in 30 percent of the horses that contract it.”

Horse owners can take several additional steps in the barn and around the farm to help protect horses from mosquito bites. Horses should be kept inside during dawn and dusk, which are peak hours for mosquito activity. Topical insect repellents labeled for use on horses may be applied. The wind generated by fans installed in horse stalls can also help deter mosquitoes. Old tires and containers should be disposed of, and standing water eliminated. Water troughs or buckets should be emptied, cleaned, and refilled every 2-3 days if possible to remove any mosquito eggs or larvae.

Mosquito Bite Prevention: To avoid mosquito bites and reduce the risk of infection, individuals should:

• Use Environmental Protection Agency (EPA)-registered insect repellents. Follow the manufacturer’s instructions for reapplication times.
• If using sunscreen, apply it first and insect repellent second.
• Adults: Spray insect repellent onto your hands and then apply it to the child’s face. Do not apply insect repellent onto a child’s hands, eyes, mouth, or on cut or irritated skin.
• Do not use insect repellent on babies younger than 2 months of age.
• When outside, wear shoes, light-colored long-sleeved shirts and pants. Dress your child in clothing that covers arms and legs. Mosquito netting can protect one’s face and neck, and infants in carriages, strollers and playpens.
• Use permethrin (an insecticide) to treat clothing and gear (such as boots, pants, socks, and tents), but do not apply to skin.
• Prevent mosquitoes from entering the house by using screens and keeping windows and doorways tightly sealed.

The Department of Natural Resources and Environmental Control’s (DNREC) Mosquito Control section announced WNV in sentinel chickens for the first time this year in July. Delawareans are reminded that the possibility of contracting mosquito-transmitted diseases, including WNV and EEE, will continue until colder autumn temperatures in mid-October or later. Until that time, in response to findings of WNV or EEE in humans or horses by the Division of Public Health and Delaware Department of Agriculture, respectively, DNREC’s Mosquito Control Section typically increases its mosquito population surveillance efforts in the vicinity of the virus findings, and then, depending on types and numbers of mosquitoes encountered, takes appropriate mosquito control measures as warranted. To report suspected cases of human WNV, call the DPH Office of Infectious Disease Epidemiology at 1-888-295-5156.

For more information about mosquitoes and mosquito-borne illnesses, use the following resources:

• For mosquito biology/ecology and control, contact the DNREC Mosquito Control section office in Dover at 302-739-9917.
• For requests for mosquito relief in upstate areas from Dover north, contact Mosquito Control’s Glasgow field office at 302-836-2555.
• For requests for mosquito relief in downstate areas south of Dover, contact Mosquito Control’s Milford field office at 302-422-1512.
• For animal health questions, contact the Delaware Department of Agriculture’s Poultry and Animal Health Section at 302-698-4561.
• To report suspected cases of human WNV, call the Division of Public Health Office of Infectious Disease Epidemiology toll-free at 1-888-295-5156.
• For more information on West Nile virus or Eastern equine encephalitis, visit www.cdc.gov/ncidod/dvbid/westnile/index.htm.

For more information on what you can do to prevent West Nile Virus, visit the Centers For Disease Control and Prevention’s website, www.cdc.gov/westnile/prevention/index.html.

No Human Cases of WNV Reported to Date in State

West Nile Virus (WNV) has been detected in Delaware for the first time in 2021 in sentinel chickens, the Delaware Department of Natural Resources and Environmental Control announced today. This first finding occurred in northern New Castle County at a sentinel chicken station sampled by DNREC’s Mosquito Control section on July 19. While there have been no reported WNV cases in humans this year in the state, Delawareans are reminded that the possibility of contracting mosquito-transmitted diseases, including WNV and Eastern Equine Encephalitis (EEE), will continue until colder autumn temperatures in mid-October or later.

Blood samples are collected by the DNREC Division of Fish and Wildlife Mosquito Control section each week from early July into October from the state’s outdoor-caged sentinel chickens that are humanely housed and handled at 20 monitoring stations statewide. The blood samples are tested for WNV and EEE antibodies by the Delaware Public Health Laboratory. Sentinel chickens bitten by mosquitoes carrying WNV or EEE develop antibodies to these diseases but are otherwise unaffected by them. WNV and EEE can be transmitted by mosquitoes to humans and horses.

Most people infected with WNV do not develop symptoms, but about 20% can develop a mild illness, which may include fever, body and muscle aches, headache, nausea, vomiting and rash symptoms. A small number of people can develop serious illness involving neurological problems, paralysis and possibly death. EEE is not as prevalent as WNV, but can present more severe symptoms in humans and horses.

DNREC reminds the public to take common-sense precautions to avoid mosquito bites, including wearing long-sleeved shirts and long pants when outdoors in mosquito-prone areas, applying insect repellent containing 10 to 30% diethyl toluamide (DEET) in accordance with label instructions and avoiding mosquito-infested areas and times of peak mosquito activity around dusk, dawn and at night.

Spraying to reduce mosquito populations in areas where WNV or EEE is detected may be initiated by the Mosquito Control section as warranted based on factors to include mosquito population levels and mosquito species present. To reduce mosquito-breeding habitat and chances of disease transmission, residents should drain or remove outdoor items that collect water, such as discarded buckets or containers, uncovered trashcans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in boat tarps, clogged rain gutters, corrugated downspout extenders and unused swimming pools.

The state veterinarian within the Department of Agriculture urges horse owners to contact their veterinarians as soon as possible to have horses and other equines vaccinated against WNV and EEE. Neither disease has a specific drug treatment, and infections in horses are fatal in 70 to 90% of EEE cases and in 30% of WNV cases.

More information about mosquitos and mosquito-borne diseases is available from the following resources:

• For mosquito biology/ecology and control, contact the DNREC Mosquito Control section office in Dover at 302-739-9917.
• For requests for mosquito relief in upstate areas from Dover north, contact Mosquito Control’s Glasgow field office at 302-836-2555.
• For requests for mosquito relief in downstate areas south of Dover, contact Mosquito Control’s Milford field office at 302-422-1512.
• For animal health questions, contact the Delaware Department of Agriculture’s Poultry and Animal Health Section, at 302-698-4500.
• To report suspected cases of human WNV, call the Division of Public Health Office of Infectious Disease Epidemiology toll-free at 888-295-5156.
• For more information on West Nile virus or Eastern equine encephalitis, visit www.cdc.gov/ncidod/dvbid/westnile/index.htm.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. The DNREC Division of Fish and Wildlife conserves and manages Delaware’s fish and wildlife and their habitats, and provides fishing, hunting, wildlife viewing and boating access on nearly 65,000 acres of public land. For more information, visit the website and connect with @DelawareDNREC on Facebook, Twitter or LinkedIn.

Media Contacts: Nikki Lavoie, nikki.lavoie@delaware.gov; Michael Globetti, michael.globetti@delaware.gov

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