The Delaware Department of Natural Resources and Environmental Control has detected Eastern Equine Encephalitis (EEE) in sentinel chickens for the first time this year. There are 20 sentinel chicken stations throughout the state, each of which are sampled every summer and fall for EEE and the West Nile Virus (WNV). Both are mosquito-transmitted viruses that have adverse effects on humans and horses.
DNREC detected WNV in 18 out of 20 sentinel chicken stations this year and detected EEE in just one station so far. Out of nearly 75 WNV-positive chickens, only two humans and one horse have tested positive for the virus. So far, no humans or horses have tested positive for EEE.
Eastern Equine Encephalitis is rarer than West Nile Virus, but is much more hazardous. Humans often experience debilitating symptoms, such as meningitis or encephalitis. The mortality rate for EEE is currently over 30%, with the old and very young as the most vulnerable populations. Symptoms of EEE start within 4 to 10 days of being bitten, and according to DNREC, early symptoms include “headache, high fever, stiff neck, tremors or muscle weakness, with more severe cases progressing to stupor, disorientation, coma, convulsions, paralysis and possibly death.” Currently, there are no vaccines for Eastern Equine Encephalitis or West Nile Virus.
Unlike those with EEE, only around 20% of WNV-infected persons show symptoms. An even smaller number experience severe symptoms such as “infection indicted by high fever, disorientation, tremors or convulsions, encephalitis or meningitis”. DNREC warns that these severe cases could result in death or long-term complications.
DNREC recommends that horse owners contact a veterinarian as soon as they suspect a horse is showing signs of either virus. Horse symptoms of EEE and WNV include loss of appetite, depression or slowness, weakness, wobbling, blindness, and tremors. Horses infected with EEE will also have a fever.
Mosquito-transmitted diseases are most prevalent in the fall, and peak time ends around mid-November. Though EEE and WNV findings in the sentinel chicken stations are not immediate cause for concern, DNREC urges Delaware residents and visitors to limit their exposure to mosquitos for the next few weeks. DNREC recommends wearing long-sleeved shirts and long pants and using insect repellant “containing 10 to 30% diethyl toluamide (DEET) or other EPA-approved insect repellents”. Most importantly, humans are encouraged to avoid mosquito-ridden areas, especially during dusk, dawn, and nighttime.
DNREC recommends draining outdoor items, removing buckets and containers, and discarding any unused item that holds stagnant water. These actions can drastically reduce habitats for mosquito-breeding.
The Mosquito Control section of DNREC has increased surveillance efforts in the areas surrounding the EEE and WNV-positive sentinel chicken stations. DNREC has provided a list of resources for more information:
- 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.