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EEE Information for Horse Owners and Other Animals

Information included for owners of Donkey, Alpaca, Llama, Emu, Pheasant and their veterinarians

Veterinarians here is the most recent Arboviral Testing Letter: https://agriculture.vermont.gov/document/arboviral-testing-letter

 

Who do I contact for free postmortem testing?

Reach out to the Vermont Department of Health Immunizations & Infectious Diseases unit at their phone: 802-863-7240 Select Option 2 (the voice prompt will say, “If you are a doctor, nurse, …”).

 

Is EEE a problem this year?

The risk to livestock is considered elevated for EEE transmission again this year, especially in Frankin and Grand Isle counties.

Over the years, arboviruses have infected various species of large animals throughout Vermont. The risk for arbovirus transmission to humans and animals is highest during late summer and early autumn. Eastern equine encephalitis virus has historically been detected in northwestern Vermont and portions of Addison and Rutland Counties and West Nile virus (WNV) has been found throughout the state. In 2023, EEE was detected in northwestern Vermont among mosquitoes and in a horse that died from its infection.

 

Where in Vermont are the hotspots?

The Department of Health mosquito-borne surveillance map has up-to-date information on what towns detections are being found in (the map includes animals, mosquitoes, and people): Mosquito-borne Virus Surveillance in Vermont (arcgis.com).

 

Should I keep my animals inside if my farm is sprayed?

Spraying takes place at night when mosquitoes are most active. The application occurs as a very fine fog that will float through mosquito habitat. The spray is designed to be a small volume that is sufficient to reduce mosquito populations but is unlikely to accumulate enough to harm larger animals, including humans and livestock. This product does not readily absorb across the skin and breaks down quickly, especially in sunlight. Even if exposures do occur, effects are unlikely because these compounds are low in toxicity to mammals and practically nontoxic to birds. Though the best practice would be to bring livestock inside when possible and wait for the product to dry before re-entering the treated areas, there is no requirement to do so or significant risk to livestock.  

 

Can my animals eat from fields that were treated with Anvil 10+10?

A best practice would be to wait for the product to dry before re-entering the treated areas, but the label does not prohibit any movement or foraging of animals in the treated area. This product is applied as a fog that moves through and around vegetation until the cloud is diluted out and breaks down rapidly especially in sunlight. It is highly unlikely that a foraging or grazing animal could consume a large enough volume of treated vegetation to cause concern before the product degrades. Even when exposures do occur effects are unlikely because these compounds are low in toxicity to mammals and practically nontoxic to birds. Because of these multiple factors, there is no significant risk to livestock. 

Animals intended for the food chain: In the event animals were exposed, USEPA has established tolerances for the active ingredients used in Anvil 10+10; reach out to VAAFM if you have concerns about selling livestock for consumption following an application over your farm.

 

What can I do to prevent EEE?

Animal owners can take the following steps to prevent EEE in humans and animals:

  • Talk with your veterinarian about animal vaccine recommendations for these diseases.
  • Reduce mosquito breeding habitats by removing standing water in outdoor items (e.g., tires, planters).
  • Keep mosquitoes from entering homes and barns by using screens and fans.
  • Prevent mosquito bites by using EPA-registered mosquito repellants on yourself and approved veterinary products for animals.

 

About EEE in Animals

EEE is a mosquito-borne viral disease caused by an Alphavirus of the family Togaviridae. It causes a progressive neurologic condition in horses and other equids. Alpacas, llamas, and emus are also susceptible to illness. The case fatality rate in affected horses is 75–90%. Clinical signs of EEE in horses include fever, depression, loss of appetite, weakness, ataxia, chewing movements, head pressing, circling, “sawhorse” stance, paddling, seizures, irritability, excitability, blindness, and abnormal sensitivity to light and sound. However, illness in horses can also be peracute, and some die suddenly without showing obvious signs or symptoms.

These signs and symptoms are not unique to EEE. Other conditions to consider include West Nile virus encephalitis, tetanus, rabies, equine herpesvirus-1, equine protozoal myeloencephalitis, and western or Venezuelan equine encephalitis.

In emus, infection typically results in a rapid onset of clinical signs, often resulting in death. Common manifestations include disseminated intravascular coagulation, severe hemorrhagic enterocolitis, and blood-tinged vomitus. Emus develop high levels of viremia, and unlike horses and humans, they may act as a reservoir for the virus. There is evidence that the vaccines available for horses may protect emus and alpacas from EEE infection.1,2

1 Tengelsen, LA et al., “Response to and efficacy of vaccination against eastern equine encephalomyelitis virus in emus” JAVMA Vol. 218, No. 9, 2001

2 Bedenice, D et al. “Humoral response to an equine encephalitis vaccine in healthy alpacas: JAVMA Vol. 234, No. 4, 2009

 

Please remember that EEE in animals are reportable in Vermont. Call the State Veterinarian’s Office at 802-828-2421 or the Health Department’s Infectious Disease Epidemiology Program at 802- 863-7240 to report cases.

Animal Health | Agency of Agriculture Food and Markets (vermont.gov)