Update: Third case of West Nile confirmed in Colleton | News | The Press and Standard
by The Press and Standard | September 28, 2017 5:00 am
Last Updated: September 27, 2017 at 10:23 am
Mosquito-borne disease affects humans as well as horses.
One horse in the Cottageville area and two more in the Walterboro area have been confirmed to be infected with West Nile Virus. Transmitted by mosquitoes, the virus also effects humans and birds.
Infection with West Nile virus does not always lead to signs of illness in people or animals. Horses appear to be a species that is susceptible to infection with the virus. Nearly 100% effective vaccinations for horses are available by contacting a veterinarian.
In horses that do become clinically ill, the virus infects the central nervous system and may cause symptoms of encephalitis.
West Nile Virus Signs In Horses
The most common signs of WNV infection in horses include stumbling, incoordination, weak limbs, partial paralysis, muscle twitching and in some cases, death. Fever has occurred in less than one fourth of all confirmed equine cases.
Each horse may exhibit a combination of symptoms or not exhibit any symptoms.
Once a horse has been bitten, it may take only 5-15 days for signs of West Nile virus to appear. Horse to horse transmission does not occur. The virus is most prevalent from May to October when mosquitoes are most abundant.
Treatment is vital for any horse with WNV. Since there is not any specific antibody to counter attack the virus, it is important to consult your veterinarian and provide supportive therapy. Depending upon the affect the virus has on each individual horse will determine if home or clinical care is warranted. Each animal is assessed according to its age and health and all treatments should be under the direction of a veterinarian.
Recovery times depend upon the health and age of the affected horse. Many horses will improve within 5-7 days of displaying clinical signs, however about 20-30% can exhibit severe neurological deficits for several weeks.
In cases of WNV, 33% will die, 50% will fully recover and 17% will have relapse or incomplete recovery.
Treatment includes treating a fever if present.
Ensure horse receives sufficient fluids, possibly through intravenous treatment if the horse is unable to drink on its own. Oral or intravenous feeding may also be necessary for horses unwilling to eat.
For horses unable to rise slinging is recommended 2-3 times per day to aid in circulation and to try to prevent pressure point sores (bed sores).
Head and leg protection is also frequently needed.
Horses with WNV sometimes develop other problems because they were weakened by WNV. Joint and tendon infections, sheath infections, pneumonia, and diarrhea can all occur as secondary events.
Horse owners should consult their veterinarians regarding vaccination. The vaccine shots are of no value if they aren’t given prior to exposure to the disease. If the horse develops WNV it is too late for the shot.
The vaccines require two doses, administered three to six weeks apart, and full protection doesn’t develop until four to six weeks after the second dose. Sometimes a third dose is recommended. Boosters are recommended, but recommendations vary and depend upon mosquito infestation where you live. It can take from 7-12 weeks for the horse to develop maximum resistance to infection.
To eliminate mosquito breeding habitats: Eliminate any unnecessary standing water on your property (tires, wheelbarrows, old buckets, etc.), make certain roof gutters drain properly and remove any standing water, especially from flat roofs, keep swimming pools clean and free of water on covers.
Stable horses inside during active mosquito feeding times (dawn/dusk), utilize fans, barrier cloths, screens, flysheets, repellent sprays (permethrin, DEET), and insecticide misting systems, turn off lights that attract mosquitoes at night, or use fluorescent lights, which do not attract mosquitoes.
It is important to note that not all horses with clinical signs of encephalitis have West Nile encephalitis. Certain other diseases can cause a horse to have symptoms similar to those resulting from infection with West Nile Virus. Those with a horse that may be exhibiting signs of encephalitis should contact their veterinarian. Laboratory tests are necessary to confirm a diagnosis.
It is important to diagnose WNV because infection is an indication that mosquitoes carrying the virus are in the area and need to be eliminated.
Colleton County is following recommendations from DHEC and the Centers for Disease Control by:
• Spraying for adult mosquitoes near the reported case;
• Removing mosquito habitats such as standing water ranging from wastewater areas to bird baths, old tires, or any container that holds water;
• Treating mosquito larvae, especially in storm drains with leaf litter or any other containers that cannot be turned over or discarded.
Individuals should pay attention to the most effective ways to prevent mosquito-borne illnesses:
• Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or IR 3535 according to label instructions. Repellents help keep mosquitoes from biting.
• Make sure that your doors and windows have tight-fitting screens to keep mosquitoes outside.
• Eliminate all sources of standing water on your property, including flowerpots, clogged gutters, buckets, neglected swimming pools, plastic sheeting or tarps used to cover yard items, pool covers, wheel barrows, children’s toys, birdbaths, old tires, rain gutters, pet bowls, and any other water-holding containers.
• Wear light-colored clothing to cover your skin and reduce the risk of bites.
The risk of serious illness or death from West Nile virus is low. Most people (8 out of 10) infected with West Nile virus have no symptoms. About one in five people infected becomes ill within two to 14 days with symptoms including fever, headache, joint pain, muscle pain, diarrhea, rash, and occasionally nausea and vomiting.
About 1 in 150 people infected develop more severe symptoms such as a potentially fatal swelling of the brain, known as encephalitis, or inflammation of the membranes that surround the brain and spinal cord, known as meningitis. Other serious symptoms include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis.
For more information about preventing mosquito bites and the spread of West Nile virus and other mosquito-borne illnesses, go to www.scdhec.gov/mosquitoes. Learn more about West Nile virus at www.scdhec.gov/westnile.