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

###

No Human Cases of WNV Have Been Reported to Date in State

West Nile Virus (WNV) was detected Aug. 27 in Delaware for the first time this year in DNREC’s sentinel chickens placed at a northern New Castle County location where the chickens are sampled regularly for the presence of the mosquito-transmitted disease. While there have been no reported WNV cases in humans this year in the state, DNREC reminds Delawareans the possibility of contracting mosquito-transmitted diseases, including WNV and Eastern Equine Encephalitis (EEE), will continue until colder autumn temperatures, usually in mid-October or later.

DNREC’s Mosquito Control section in the Division of Fish and Wildlife collects blood samples each week from early July into October from the 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 but are otherwise unaffected by the diseases. WNV and EEE can both 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. 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% 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.

DNREC also may initiate mosquito spraying in areas where WNV or EEE is detected based on factors to include mosquito population levels and 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.

Meanwhile, 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 EEE infections in horses are fatal in 70 to 90% of cases, and WNV in 30% of cases.

More information 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 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 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 DNREC on Facebook, Twitter or LinkedIn.

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

###

DOVER – DNREC’s Division of Fish & Wildlife Mosquito Control Section is seeking the public’s help in monitoring West Nile virus (WNV) in Delaware by reporting sick or dead wild birds that may have contracted the virus. WNV is a mosquito-transmitted disease of considerable concern to human health and to owners of unvaccinated horses.

DNREC’s Mosquito Control Section requests that the public report sick or dead wild birds of the following species only: crows, blue jays, cardinals, robins, hawks, or owls. Clusters of five or more sick or dead wild birds of any species should also be reported. Bird specimens should have been dead for less than 24 hours and not appear to have died from other obvious causes. Wild birds collected by Mosquito Control are processed by the Delaware Department of Agriculture’s Poultry & Animal Health Lab, and then submitted to the Division of Public Health (DPH) Laboratory for virus testing. Uncollected dead wild bird specimens are very unlikely to transmit WNV to humans or pets.

To report sick or dead birds, call Mosquito Control’s field offices between 8 a.m. and 4 p.m., Monday through Friday:

• New Castle County and Kent County from Dover north, Glasgow office: 302-836-2555
• Remainder of Kent County and Sussex County, Milford office: 302-422-1512

From July through mid- to late-October, the Mosquito Control Section also operates a statewide network of about 20 sentinel chicken stations in prime mosquito areas, collecting blood samples to be tested by the DPH Lab for WNV and eastern equine encephalitis (EEE), another mosquito-transmitted viral disease that affects humans and horses. The sentinel chicken virus test results help indicate where and when WNV or EEE has been transmitted by mosquitoes from wild bird hosts to other animals, possibly leading to an increased risk of exposure for humans or horses. Neither WNV nor EEE can be transmitted between horses, or from horses to people, or between people.

The period of greatest concern for disease transmission for WNV and EEE is late summer and early fall. WNV is transmitted to humans primarily by the common house mosquito, and possibly by the Asian tiger mosquito. Last year, Delaware had 10 reported WNV-human cases, two of which were fatal. Nationwide, the Centers for Disease Control (CDC) logged 2,544 reported WNV-human cases in 2018 that resulted in 137 deaths, 27 of which occurred in our Mid-Atlantic region. In Delaware last year, five WNV-equine cases were reported, in which two unvaccinated horses had to be humanely euthanized.

Residents also are encouraged to call to report intolerable numbers of biting mosquitoes and request control services. Voicemail may be left after hours, or on weekends or holidays.

For more information, call Delaware Mosquito Control’s main office at 302-739-9917, or visit the Mosquito Control web pages.

For more information about West Nile virus or eastern equine encephalitis in humans, call the Delaware Division of Public Health at 302-744-4990 or 888-295-5156.

For more information about West Nile virus or eastern equine encephalitis in horses, or horse vaccines, call the Delaware Department of Agriculture’s Poultry and Animal Health Section at 800-282-8685 (Delaware only) or 302-698-4500.

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

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.

# # #

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

DOVER, Del. – The Office of the State Veterinarian announced today Delaware’s third case of West Nile Virus (WNV) found in horses in 2018.

The infected equine is a 10-year-old pony gelding that was purchased from a Pennsylvania livestock auction and transported to a premises in New Castle County, DE on August 27. On August 30, the pony was observed to have a fever, was leaning and walking sideways. He progressed to show signs of wobbling and staggering, decreased tail tone, and facial nerve deficits. Samples were submitted to the National Veterinary Services Laboratory, which confirmed the diagnosis of WNV on September 7. The vaccination history for this pony is unknown. His condition is reported to be improving.

This is the third case of WNV reported in Delaware horses in 2018. The first and second cases were diagnosed in August, and occurred in a 3-year-old Standardbred mare residing in Kent County with unknown vaccination status and a 2-year-old Thoroughbred mare also residing in Kent County that was not up-to-date on its WNV vaccine. The Thoroughbred horse was euthanized due to the severity of its illness.

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. Three detections of EEE, two in Sussex and one in New Castle County, have been made in sentinel chickens in the last month. So far in Delaware in 2018, five cases of WNV have been found in humans.

The State Veterinarian urges horse owners to contact their veterinarians as soon as possible, as we are in the midst of peak mosquito season, 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:

• Human health questions should be directed to the Delaware Division of Public Health, (888) 295-5156, or (302) 744-4990.

• 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.

# # #

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