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


Third equine case of West Nile Virus confirmed in Delaware

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.

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


Sussex County Man Tests Positive for West Nile Virus

DOVER – The Division of Public Health (DPH) is announcing that a 60-year-old Sussex County man has tested positive for the state’s first human case of West Nile Virus (WNV) in 2018. The man was briefly hospitalized for illness in July and after a preliminary positive test result from the DPH Laboratory in Smyrna, the blood sample was sent to the Centers for Disease Control and Prevention (CDC) for confirmatory testing. WNV, a mosquito-borne illness, can become serious, and DPH reminds people to take precautions to avoid mosquito bites. In 2017, one case of WNV was confirmed in a Kent County woman, the first such case in two years in Delaware.

The Department of Natural Resources and Environmental Control (DNREC) Mosquito Control Section has seen an increase of WNV found in wild birds and sentinel chickens. The first case of WNV in birds this year was detected in late June in a wild crow collected in Sussex County by DNREC’s Mosquito Control section. WNV-positive sentinel chickens have been found at 10 of the 20 Mosquito Control Section sentinel chicken stations around the state, with virus-positive stations now in all three counties, and 13 WNV-positive wild birds have also been collected from all three counties. The increase in WNV detection in birds is occurring at about twice the normal rate, according to DNREC Mosquito Control officials.

“With the appearance of this disease in a person, along with an accompanying increase of West Nile Virus in wild birds, we want to urge everyone to protect yourself and your loved ones from mosquito bites. These bites can cause much more serious health problems than just itching and discomfort,” said DPH Director Dr. Karyl Rattay. “This is an early start to the transmission season for West Nile Virus, and it is concerning that we could see more cases this year in humans than in past years.”

WNV and EEE are transmitted by mosquitoes, generally in summer and fall, with a peak period for disease transmissions from mid-August to mid-October. Although nearly 80 percent of people infected with WNV will not become ill, and only a little less than 20 percent of those infected 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.

WNV is primarily transmitted to humans by the common house mosquito, while the Asian tiger mosquito can also carry the disease. Mosquitoes in Delaware can also carry viruses that may result in death, including Eastern equine encephalitis (EEE), which can cause brain inflammation and be fatal to humans and horses, and dengue virus.

Earlier this month, DNREC’s Mosquito Control Section found Delaware’s first EEE-positive sentinel chicken for 2018 in a station in Sussex County. Like WNV, EEE can adversely affect both humans and horses – EEE is more severe than WNV, but fortunately much rarer. Heightened concerns over possible transmission to humans from both viruses, will continue into mid-October, until cooler temperatures start to significantly slow down both mosquito and virus activity.

Other mosquito-borne diseases that could occur in Delaware include chikungunya, which while rarely fatal, may result in severe and debilitating symptoms, including fever and joint pain, and Zika. The most common symptoms of Zika are rash, fever, joint pain, and conjunctivitis (red eyes). The largest health impact of the Zika virus appears to be on infants whose mothers were infected during pregnancy. There have been reports of a serious birth defect of the brain called microcephaly, a condition in which a baby’s head is smaller than expected when compared to babies of the same sex and age, as well as other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. To date, no cases of Zika in the state have been linked with local mosquito or human transmission.

DNREC’s Mosquito Control Section dealt with a statewide eruption of adult mosquitoes from late May through the end of June, occurring primarily in inland areas and caused by heavy rainfall. For the past two weeks the agency has faced another onslaught of adult mosquitoes in coastal areas attributable largely to tidal flooding and rains. To help the Section combat swarming numbers of mosquitoes this year, and to reduce mosquito-breeding habitat for mosquitoes that can transmit WNV, DNREC urges homeowners to practice good water sanitation on their property by eliminating standing water, particularly as might be collected in buckets, containers, uncovered trash cans, stagnant bird baths, old tires, and unused swimming pools.

To avoid mosquito bites and reduce the risk of infection, individuals should also:
• When outside, wear shoes, light-colored long-sleeved shirts and pants. Mosquito netting can protect one’s face and neck, and infants in carriages, strollers, and playpens. Mosquitoes are most active at dusk and during the early-morning hours.
• Use Environmental Protection Agency (EPA)-registered insect repellents. Follow the manufacturer’s instructions for reapplication times.
• Do not use insect repellent on babies younger than 2 months of age.
• Dress your child in clothing that covers arms and legs. Do not apply insect repellent onto a child’s hands, eyes, mouth, or on cut or irritated skin. Adults: Spray insect repellent onto your hands and then apply to the child’s face.
• Prevent mosquitoes from entering the house by using screens and keeping windows and doorways tightly sealed.

While there are no vaccines against WNV or EEE for humans, effective EEE and West Nile vaccines are available for horses through veterinarians, according to the Delaware Department of Agriculture’s State Veterinarian’s Office. Both WNV and EEE cause severe, and sometimes fatal, infections in horses. 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.

To report suspected cases of human WNV, call the DPH Office of Infectious Disease Epidemiology at 888-295-5156.

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 horses and equine vaccines – Contact the Department of Agriculture’s Poultry and Animal Health Section at 302-698-4500 or 800-282-8685 (Delaware only).
• For more information on West Nile virus or Eastern equine encephalitis – Visit the CDC website, www.cdc.gov/ncidod/dvbid/westnile/index.htm

A person who is deaf, hard-of-hearing, deaf-blind or speech-disabled can call the DPH phone number above by using TTY services. Dial 7-1-1 or 800-232-5460 to type your conversation to a relay operator, who reads your conversation to a hearing person at DPH. The relay operator types the hearing person’s spoken words back to the TTY user. To learn more about TTY availability in Delaware, visit http://delawarerelay.com.

Delaware Health and Social Services is committed to improving the quality of the lives of Delaware’s citizens by promoting health and well-being, fostering self-sufficiency, and protecting vulnerable populations. DPH, a division of DHSS, urges Delawareans to make healthier choices with the 5-2-1 Almost None campaign: eat 5 or more fruits and vegetables each day, have no more than 2 hours of recreational screen time each day (includes TV, computer, gaming), get 1 or more hours of physical activity each day, and drink almost no sugary beverages.


Multi-agency approach helps DDA and DNREC protect pollinators in Delaware

DOVER, Del. – Farmers throughout Delaware depend on both honeybees and native bees to pollinate their crops each year. It takes nearly 300 million honeybees to successfully pollinate these crops, which bring more than $38.7 million to the state’s economy.

“The health of pollinators within Delaware is extremely important to the success of our family farms,” said Secretary of Agriculture Michael T. Scuse. “From early spring all the way through late summer, bees are pollinating crops that Delawareans love to eat – strawberries, blueberries, watermelon, cantaloupes, cucumbers, apples, squash, cranberries, and pumpkins. Our staff works throughout the year to ensure the safety of bees and to help increase the number of healthy colonies within the state.”

In 2016, the Delaware Department of Agriculture (DDA) released

The Delaware Department of Agriculture maintains bee hives for education and demonstration purposes.

Delaware’s Managed Pollinator Protection Plan that outlines strategies, best practices, and resources that beekeepers, farmers, landowners, and pesticide applicators can use to help protect and enhance bees and other pollinators. In conjunction with the release of this plan, the Department’s Plant Industries section secured a USDA Specialty Crop Block Grant to engage Delaware fruit and vegetable growers and beekeepers in the implementation of the plan to improve the availability and quality of bee forage and to decrease the bees’ risk of pesticide exposure. Both efforts combined to improve the health and vitality of bees, which in turn enhance pollination of crops and also enable increased production of local honey.

“One of the key best management practices that we learned in talking with all the groups involved in developing the pollinator protection plan is communication,” said Laura Mensch, DDA Hydrologist III. “We invested in DriftWatch so that pesticide applicators could check where beekeepers have their hives located before spraying – either on the ground or by aerial application. We are excited to see the recent release of the mobile DriftWatch apps, increasing the potential use and benefit of the tool.” In April 2018, FieldWatch launched two free mobile apps (both Android and iOS) called FieldCheck and BeeCheck. The goal is to make it easier for users to access the DriftWatch map while they are on the go. These new apps will allow more users, especially applicators, to access the specialty crop and beehive data on a highly functional mobile platform.

DDA asks beekeepers to register with BeeCheck so that pesticide applicators know where hives are located when they head out to spray. According to DDA State Apiarist Meghan McConnell, there are 289 registered beekeepers with 5,934 colonies in-state for 2018, but there are only 77 beekeepers registered with BeeCheck. One of those pesticide applicators is the Department of Natural Resources and Environmental Control’s Delaware Mosquito Control Section. For public awareness, including beekeepers, the Mosquito Control Section implemented a Spray Zone Notification (SZN) System, enabling a registered user to receive an alert via text, phone, or email of upcoming spray activities. Recently, two beekeepers expressed concerns regarding mosquito control aerial spraying in Sussex County and alleged impacts to the health of honeybees used for pollination there. Neither had registered with the Spray Zone Notification System.

The Mosquito Control Section’s primary work is preventing mosquito-borne diseases in humans, domestic livestock, and pets, and helping promote and maintain good quality-of-life for Delawareans and visitors, while also lessening adverse impacts to local economies that severe mosquito infestations can cause. Nineteen of the 57 mosquito species found in Delaware are known to bite humans and several can transmit mosquito-borne diseases such as Eastern equine encephalitis and West Nile virus. In particular, the native common house mosquito is primarily a nighttime biter but is also active around dawn and dusk, and is the primary transmitter for West Nile virus in Delaware.

Eliminating breeding habitat is the best means of controlling several types of mosquitoes, but control of other species that can also transmit disease or severely affect quality-of-life often relies on timely insecticide treatments for larval or adult mosquito stages. Therefore, the Mosquito Control Section flies over areas that could become mosquito-infested, applying larvicides to water bodies as a preventive measure and adulticides if an area is already infested, and spraying only by adhering to strict protocols for public health and safety including use only of EPA-approved pesticides.

In collaboration with DDA on the Delaware Managed Pollinator Protection Plan, DNREC’s Mosquito Control Section updated standard operating procedures (SOPs) when treatments are needed around honeybees or their hives. More information on DNREC’s rationale behind their work with bees is available online.

DNREC utilizes Integrated Pest Management (IPM), employing wherever practicable non-insecticidal, source reduction measures such as water management or fish-stocking for larval mosquito control. If source reduction cannot be used or is ineffective, larvicide spraying for mosquito control is used – but such spraying does not have potential for conflicts with pollinating activities, since larvicides are applied primarily in marshes or wet woodlands, and do not have modes of action that would adversely affect honeybees.

As a last option, if larviciding cannot be done or has proven ineffective, DNREC’s Mosquito Control utilizes adulticides applied by aircraft or via truck-mounted sprayers. Aerial applications occur during late evening or early morning, for more effective mosquito control and also to minimize adverse impacts to honeybees, since they are less active or already back in their hives. Ground application of adulticides by truck-mounted sprayers (“fogging”) almost always occurs at night when honeybees are in the hive.

“The Delaware Beekeepers Association (DBA), along with Delaware Department of Natural Resources and Environmental Control (DNREC) share a common goal – to maintain a healthy population of managed honeybee colonies in Delaware,” said DBA Secretary Rebecca Rendeiro. Aerial spraying for mosquitoes is complex, and while it does not affect every beekeeper, it is important that that there are measures in place to help protect bees to decrease the chance of a colony loss due to pesticide application, while at the same time still enabling adequate mosquito control.

Also, Delaware Department of Agriculture’s pesticide inspectors work in each county to ensure pesticides are properly applied. “Our inspectors conduct announced and unannounced visits throughout the state, including inspections of DNREC’s Mosquito Control applicators,” said DDA Pesticide Administrator Christopher Wade. “We make sure that applicators are using the product properly and safely according to the label specifications in order to protect the health of the public and pollinators.”

If beekeepers suspect that their colonies have been affected by pesticides, they can file a complaint with the Department of Agriculture. In the past year, three complaints were filed and investigated, all crop-related and none involving Mosquito Control spraying. Wade said, “We take a team approach to our investigation since we now have Meghan (McConnell, State Apiarist) on staff. Our inspectors collect samples for pesticide analysis and Meghan looks at the health of the colony and can determine if there are any other health concerns for the bees. It’s helpful for the beekeeper to have their colonies inspected.” In one instance, a notice of warning was issued to the applicator and the grower to be mindful of label directions, and an advisory was issued to the beekeeper for not alerting the grower that hives were on the premises.

Similarly, after decades of Mosquito Control adulticiding, reports of suspected damages to honeybees or hives from such treatments are few. “When we look at bee health and the number one loss for colonies in Delaware, it’s not pesticides,” said State Apiarist McConnell. “Delaware has been fighting Varroa mites since 1994 and Small Hive Beetle since 2001. When we look at colony loss in Delaware, the majority is caused by Varroa mites and the viruses transmitted by them. Bees will not survive the winter, even with enough honey stores, if there are viruses and diseases present.”

Collaboration between state agencies and beekeepers is the key to keeping honeybees safe. DNREC’s Mosquito Control Section has implemented tools to assist beekeepers and to help keep the public informed in advance of mosquito control spray activities. Beekeepers (and members of the public) can sign up for the Mosquito Control Spray Zone Notification System, a two-step process that allows a user to select their spray zone area of interest and then register to receive an alert via text, phone, or email of upcoming spray activity in that area. If beekeepers have concerns on where or when spraying is scheduled to take place relative to beehive locations or honeybee foraging areas, they should contact the Mosquito Control Section to express their concerns.

As a pesticide applicator, DNREC’s Mosquito Control Section also has the ability to check the FieldCheck and BeeCheck apps, and plan spray operations to the extent practicable around data taken from those apps. But if beekeepers have not registered with Mosquito Control’s spray notification system, or if their beehive locations are not kept up to date in FieldCheck and BeeCheck, DNREC’s Mosquito Control Section will not know that hives are located in an area when spraying there for mosquitoes.

The Delaware Department of Agriculture, DNREC’s Mosquito Control Section and the Delaware Beekeepers Association urge anyone who keeps bees in Delaware to register their bee hives and sign up for all the apps that are available that can help protect the state’s valuable pollinators.

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Media Contact: Stacey Hofmann, 302-698-4542, stacey.hofmann@delaware.gov


Heavy rains prompt mosquito alert and advisory; DNREC Mosquito Control working to thwart big rise in numbers

DOVER (June 11, 2013) – Due to heavy rainfall Delaware has received in the last week – and with more rain forecast through the weekend – there will be plenty of surface water for the state’s mosquito species to lay their eggs with great numbers of mosquitoes expected to hatch in the near future.  

This confluence of ideal breeding conditions for mosquitoes means homeowners should eliminate as much standing water found in containers from their property as quickly as possible – and encourage their neighbors to do the same. By draining or removing items that collect water, such as buckets, birdbaths, rain barrels, old tires, flower pot liners, depressions in tarps covering boats, clogged rain gutters, and unused swimming pools, homeowners can significantly reduce mosquito breeding habitat in their yards. 

DNREC Mosquito Control staff will be going through their normal triage of inspecting and treating the largest mosquito-producing habitats, including coastal marshes, impoundments, freshwater wetlands, inter-dunal swales, and problematic roadside ditches/medians. However, Mosquito Control has a limited amount of time to inspect and treat all of the above habitats before adult mosquitoes emerge. Even if successful on every aspect, waves of adult mosquitoes will be emerging over the next two weeks from untreated yards, ditches, flooded fields, woodland pools, and other habitat that Mosquito Control did not have the resources to inspect/treat due to the sheer volume of geography to cover after a statewide rain episode of this magnitude. 

The only recourse at this time is for the public to call DNREC Mosquito Control and request ultra-low volume spraying (fogging) to reduce the number of adult mosquitoes in a given area. This includes neighborhoods, developments, towns, and individual rural properties. Anyone planning outdoor events during the second half of June also should consider this request to the Mosquito Control Section in advance of the event. 

To help the Mosquito Control Section determine when and where to provide control services, report intolerable numbers of biting mosquitoes as follows:

  • New Castle County and northern Kent County from Dover north, call Mosquito Control’s Glasgow office at 302-836-2555
  • Remainder of southern Kent County and all of Sussex County, call Mosquito Control’s Milford office at 302-422-1512

For more information on Delaware’s Mosquito Control program, please call the main office at 302-739-9917, or visit http://www.fw.delaware.gov/Services/Pages/MosquitoSection.aspx.

 Contact: Michael Globetti, DNREC Public Affairs, 302-739-9902

Vol. 43, No. 241

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