First 2022 Delaware Evidence of Eastern Equine Encephalitis Detected in DNREC’s Sentinel Chickens

Public Urged to Take Precautionary Measures Until Colder Weather Arrives in The Fall

Eastern Equine Encephalitis (EEE), a mosquito-transmitted disease, has been detected in Delaware the first time for 2022 in a sentinel chicken, the Delaware Department of Natural Resources and Environmental Control announced today. Mosquito-transmitted virus detections in DNREC’s sentinel chickens are unrelated to Delaware’s poultry industry.

The EEE finding in northern New Castle County was from a sentinel chicken station sampled by the DNREC Division of Fish and Wildlife Mosquito Control section and confirmed by the Delaware Public Health Laboratory Aug. 9. While there have been no reported EEE cases in humans this year in the state, Delawareans are reminded that the possibility of contracting mosquito-transmitted diseases, including EEE and West Nile Virus (WNV), will continue until colder autumn temperatures in late-October or later.

The first EEE-positive sentinel chicken for this year adds to five WNV-positive sentinel chickens found earlier at three other sentinel chicken arbovirus monitoring stations in New Castle and Kent counties – with the first WNV finding occurring in early July. No EEE or WNV human cases have been reported to date in 2022 by the Delaware Public Health Laboratory, nor have any EEE or WNV equine cases been reported by the Delaware Department of Agriculture.

Blood samples are collected by the 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 EEE and WNV antibodies by the Delaware Public Health Laboratory. Sentinel chickens bitten by mosquitoes carrying EEE or WNV develop antibodies to these diseases but are otherwise unaffected. Mosquitoes can transmit both WNV and EEE to humans and horses.

The public is reminded 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% 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.

Spraying to reduce mosquito populations in areas where EEE or WNV is detected may be initiated by DNREC’s 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.

While EEE is rarer than WNV, both EEE and WNV can adversely affect people and horses. Most people who become infected with EEE virus and WNV show either no or mild symptoms. Early symptoms in people contracting EEE or WNV can be similar, but EEE often becomes more pronounced and debilitating, manifested by meningitis or encephalitis typically resulting in hospitalizations. EEE has a higher human mortality rate of approximately 30%, with infants, children and the elderly most vulnerable, according to the U.S. Centers for Disease Control and Prevention. Symptoms in people infected with EEE usually start from four to 10 days after being bitten by a mosquito infected with EEE. Early EEE symptoms can include headache, high fever, stiff neck, tremors or muscle weakness, with more severe cases progressing to stupor, disorientation, coma, convulsions, paralysis and possibly death. 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 infected with WNV can develop serious illness involving neurological problems, paralysis and possibly death. There are no human vaccines for EEE or WNV. Anyone developing the symptoms described above should see their healthcare provider.

Horse owners should contact their veterinarian immediately if they suspect their horse may be showing signs of WNV or EEE. Symptoms of EEE in horses include fever (102.5-104.5°F), loss of appetite, head pressing, depression or personality change, wobbling or staggering, weakness, blindness, convulsions, muscle tremors in the head and neck or hind-limb weakness. These signs are also consistent with WNV, although a fever may or may not be present with WNV.

Additional information about mosquitoes and mosquito-transmitted diseases is available from the following resources:

For mosquito biology/ecology and control, contact the 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 EEE or WNV, call the Division of Public Health Office of Infectious Disease Epidemiology toll-free at 888-295-5156.
For more information on Eastern Equine Encephalitis or West Nile Virus, 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 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; Joanna Wilson, joanna.wilson@delaware.gov

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First 2022 Delaware Evidence of West Nile Virus Detected in DNREC’s Sentinel Chickens

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

West Nile Virus (WNV) has been detected in Delaware the first time for 2022 in a sentinel chicken, the Delaware Department of Natural Resources and Environmental Control announced today. This initial finding was from a sentinel chicken station in southern New Castle County sampled by the DNREC Division of Fish and Wildlife Mosquito Control section and confirmed by the Delaware Public Health Laboratory 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 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. 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 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 2021. With the detection of WNV in a sentinel chicken this early in the season, the state veterinarian urges horse owners to contact their veterinarians as soon as possible 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 2021. 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.

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

For mosquito biology/ecology and control, contact the 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.

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

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Mosquito-transmitted Eastern Equine Encephalitis Detected in DNREC’s Sentinel Chickens

Public Urged to Take Precautionary Measures Until Colder Weather Arrives

Eastern Equine Encephalitis (EEE), a mosquito-transmitted disease, has been detected in Delaware for the first time in 2021, at a sentinel chicken station in southwestern Sussex County sampled Oct. 11 by the Delaware Department of Natural Resources and Environmental Control to monitor for certain mosquito-transmitted diseases. Twenty sentinel chicken stations are sampled weekly throughout the state each summer and fall to help track Eastern Equine Encephalitis (EEE) and West Nile virus (WNV), the primary mosquito-transmitted diseases that are human health threats in Delaware. Mosquito-transmitted virus detections in DNREC’s sentinel chickens are unrelated to Delaware’s poultry industry.

The first EEE finding in Delaware adds to an active year for WNV, which has been detected in 18 of DNREC’s 20 sentinel chicken stations involving a total of 74 WNV-positive chickens from late July to date. Two WNV-human cases have been reported to date in 2021 by the Delaware Public Health Laboratory, and one WNV-equine case has been reported by the Delaware Department of Agriculture. No EEE cases have been reported in humans or horses to date in 2021.

While EEE is rarer than WNV, both EEE and WNV can adversely affect people and horses. Early symptoms of contracting EEE or WNV can be similar, but EEE often becomes more pronounced and debilitating, manifested by meningitis or encephalitis typically resulting in hospitalizations. EEE has a higher human mortality rate of over 30%, with infants, children and the elderly most vulnerable, according to the U.S. Centers for Disease Control and Prevention. Symptoms of EEE usually start from 4 to 10 days after being bitten by a mosquito infected with EEE. Early EEE symptoms can include headache, high fever, stiff neck, tremors or muscle weakness, with more severe cases progressing to stupor, disorientation, coma, convulsions, paralysis and possibly death. There are no human vaccines for EEE or WNV.

About 80% of people infected with WNV do not show symptoms. About 20% of those infected with WNV develop mild symptoms such as fever, headache, body aches, a skin rash on the chest or back and swollen lymph glands. About one in 150 people infected with WNV might develop severe infection indicted by high fever, disorientation, tremors or convulsions, encephalitis or meningitis, all possibly leading to hospitalization and very rarely death. Survivors of severe cases of WNV can have long-lasting medical complications, including lingering paralysis.

Horse owners should contact their veterinarian immediately if they suspect their horse may be showing signs of WNV or EEE. Symptoms of EEE in horses include fever (102.5-104.5°F), loss of appetite, head pressing, depression or personality change, wobbling or staggering, weakness, blindness, convulsions, muscle tremors in the head and neck, and hind-limb weakness. These signs are also consistent with WNV, although a fever may or may not be present with WNV.

Fall is the peak time of year for mosquito-transmitted disease activity, which will continue until colder weather, possibly until early- to mid-November. While the recent EEE and WNV findings are not cause for alarm, Delaware residents and visitors are urged to be vigilant over the next few weeks to avoid or reduce exposures to mosquito bites. People should take precautions when outdoors in mosquito-prone areas, including wearing long-sleeved shirts and long pants, applying insect repellent containing 10 to 30% diethyl toluamide (DEET) or other EPA-approved insect repellents in accordance with label instructions and avoiding mosquito-infested areas and times of peak mosquito activity around dusk, dawn and at night.

To reduce mosquito-breeding habitat and mosquito populations and chances for disease transmission, DNREC’s Mosquito Control section recommends that property owners drain or remove outdoor items that collect water, such as discarded buckets or containers, uncovered trashcans, stagnant birdbaths, uncovered rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners and saucers, depressions in boat tarps, clogged rain gutters, corrugated downspout extenders and unused swimming pools.

In response to EEE and WNV activity, DNREC’s Mosquito Control section has increased mosquito population surveillance efforts in the vicinity of virus-positive findings and initiated targeted mosquito control actions as warranted, based on the mosquito species and numbers encountered.

Additional information about mosquitoes and mosquito-transmitted diseases is available from the following resources:

For mosquito biology/ecology and control, contact the 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 EEE or WNV, call the Division of Public Health Office of Infectious Disease Epidemiology toll-free at 888-295-5156.
For more information on Eastern Equine Encephalitis or West Nile Virus, visit www.cdc.gov/westnile/index.html.

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

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Delaware announces two more cases of West Nile Virus in horses

DOVER, Del. – The Office of the State Veterinarian announced today Delaware’s fourth and fifth cases of West Nile Virus (WNV) found in horses in 2018. Three previous cases of WNV in horses were reported in 2018, two in August and one in September.

The fourth case of WNV confirmed in a Delaware horse occurred in a 1-year-old Standardbred mare residing in Kent County. The horse received veterinary care for loss of control of limbs and buckling over in the front limbs which began on October 11. Clinical signs progressed to inability to rise, muscle twitching, and stupor. The horse was euthanized on October 15 due to the severity of its illness. She had not been vaccinated for WNV. New Bolton Center Clinical Pathology Laboratory reported positive WNV results on October 19.

The fifth infected horse is a 6-year-old Belgian mare residing in Kent County that was evaluated by a veterinarian for whole body stiffness, acting sore, and abnormal mentation consisting of aggression with a date of onset of October 12, 2018. Diagnostic specimens were submitted to the National Veterinary Services Laboratory, which confirmed the diagnosis on October 23. The mare had never been previously vaccinated against WNV. She was treated supportively and her condition was improving as of October 18.

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. Two cases of WNV were confirmed in Delaware horses in 2017.

The Department of Natural Resources and Environmental Control’s (DNREC) Mosquito Control Section has seen an increase of WNV found in wild birds and sentinel chickens this year throughout the state. There have been a total of eight EEE-positive sentinel chickens and WNV has been detected in 66 sentinel chickens and 37 wild birds. So far in Delaware in 2018, eight cases of WNV have been found in humans.

Even though we are nearing the end of the mosquito season, the State Veterinarian 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 EEE infections in horses are fatal in 70 to 90 percent of cases, and WNV in 30 percent of cases.

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.

For more information about WNV or EEE:
• To report suspected cases of human West Nile Virus, call the DPH Office of Infectious Disease Epidemiology at 888-295-5196.
• Animal health questions should be directed to the Delaware Department of Agriculture at 800-282-8685 (Delaware only) or 302-698-4500. Ask for the Poultry and Animal Health Section.
• Questions about the state’s mosquito control program or mosquito biology should be directed to the Delaware Department of Natural Resources and Environmental Control’s Mosquito Control Section at 302-739-9917.

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Media Contact: Stacey Hofmann, 302-698-4500, stacey.hofmann@delaware.gov

DNREC’s Mosquito Control Section announces expanded detection of Eastern Equine Encephalitis

Continued awareness and precautions encouraged

DOVER (Sept. 20, 2018) – The recent detection of Eastern Equine Encephalitis (EEE) in sentinel chickens monitored for mosquito-borne diseases by the DNREC Division of Fish & Wildlife’s Mosquito Control Section reinforces the fact that mosquitoes remain active and that precautions should continue to be taken to avoid mosquitoes whose bites could transmit EEE and other mosquito-borne diseases.

Test results reported to the Mosquito Control Section last week by the Delaware Division of Public Health Laboratory indicated EEE-positive chickens from three additional stations of the 20 stations monitored by the Mosquito Control Section throughout the state. Two of these positive stations were in New Castle County and one in Sussex County, increasing the total number of EEE-positive sentinel chicken stations this year to six: three in New Castle County and three in Sussex County. This higher-than-average detection rate for EEE suggests increased EEE activity and distribution in Delaware.

Eastern Equine Encephalitis is a rare, but potentially fatal, viral disease spread by mosquitoes, and is considered one of the more serious mosquito-borne illnesses. Although there is an EEE vaccine for horses, an EEE vaccine is not available for people. No human cases of EEE have been reported to date this year in Delaware.

Anyone in an area where the virus is circulating can be infected with EEE. The risk is highest for people exposed to high numbers of mosquito bites, including people who live in, visit, or work outside in areas with high mosquito populations where there is greater exposure to potentially infected mosquitoes. Those over age 50 and under age 15 appear to be at greatest risk for developing severe disease when infected with EEE.

While most patients infected with EEE have no apparent illness, severe cases of EEE (involving encephalitis, an inflammation of the brain) begin with the sudden onset of headache, high fever, chills, and vomiting. The illness may then progress into disorientation, seizures, or coma. Symptoms of EEE often appear four to 10 days after being bitten by an infected mosquito. Approximately 33 percent of EEE cases lead to death, and many of those who do survive experience significant brain damage. There is no specific treatment for EEE; care is based on symptoms. If you think you or a family member may have contracted EEE, it is important to consult your health care provider for proper diagnosis.

In response to DNREC’s recent EEE detections, along with ongoing West Nile virus activity, the Mosquito Control Section will increase mosquito population surveillance in areas where these detections have occurred and take mosquito control actions as warranted to include possible aerial spraying and/or fogging with a spray truck. However, the best protection to lessen the chance of contracting a mosquito-borne disease is to avoid mosquito bites by:

Properly using insect repellent containing DEET whenever outdoors;
Covering up exposed skin as much as possible by wearing long-sleeved shirts and pants; and
Avoiding known high mosquito population areas or being outside during times of peak mosquito activity, typically dawn and dusk.

In addition to avoiding mosquito bites, the Mosquito Control Section advises residents to also reduce mosquito breeding habitat on their individual properties and communities/neighborhoods by draining or removing items that collect water, such as discarded buckets or containers, uncovered trash cans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flower pot liners, depressions in tarps covering boats, clogged rain gutters, corrugated downspout extenders and unused swimming pools.

The Mosquito Control Section also encourages residents to report intolerable numbers of biting mosquitoes by calling the numbers below between 8 a.m. and 4 p.m. Monday through Friday. Callers after business hours or during weekends or holidays should leave their name, phone number, address and a brief message.

Glasgow Office, serving New Castle County and northern Kent County including the Dover area: 302-836-2555
Milford Office, serving Sussex and southern Kent counties: 302-422-1512

For more information about:

Mosquito biology/ecology and control – Contact the Mosquito Control Section’s Dover office at 302-739-9917.
Reporting WNV-suspect wild birds, or for requests for mosquito relief – For upstate areas from Dover north, contact Mosquito Control’s Glasgow field office at 302-836-2555; for downstate areas south of Dover, contact Mosquito Control’s Milford field office at 302-422-1512.
WNV or EEE in humans and related medical issues – Contact the Delaware Division of Public Health at 888-295-5156.
Animal health questions should be directed to the Delaware Department of Agriculture at 800-282-8685 (Delaware only) or 302-698-4500. Ask for the Poultry and Animal Health Section.
For more information on West Nile Virus or Eastern equine encephalitis – Visit the CDC website, www.cdc.gov/ncidod/dvbid/westnile/index.htm.

Contact: Joanna Wilson, DNREC Public Affairs Office, 302-739-9902

Vol. 48, No. 253