State Fairgrounds - P.O. Box 19281 - Springfield, IL 62794-9281 - 217/782-2172 - TDD 217/524-6858 - Fax 217/785-4505

Alerts and Important Animal Health Information

Health Alert: Equine Herpes Virus

Equine Herpes Virus (EHV-1) impacts horses and can cause respiratory disease, abortion in mares, neonatal foal death, and/or neurologic disease. The virus can spread through the air, contaminated equipment, clothing and hands.   According to the University of Kentucky Equine Research Center, the virus’s ability to reside as a silent and persistent infection in horses provides for continual transmission. It is vital that good biosecurity measures be implemented on exposed premises.

Updated 5/26/15:

No additional cases of EHV-1 have been reported to the Bureau of Animal Health and Welfare since the last update, however, while EHV-1 is a contagious and infectious disease, it is not considered to be reportable under Illinois law.

Horse Shows / Events:

The Department of Agriculture has not canceled or recommended the cancelation of any shows or events.  The decision whether or not to cancel a show or event is that of the event organizer.  Horse owners should consult with their veterinarian when making the decision whether or not to attend a show or event.  Owners need to be mindful that EHV is prevalent throughout the equine population and anytime horses are commingled, or placed in close contact with other horses there is the potential for exposure to the virus.


Horses residing at the affected stable continue to recover.  No additional fevers or clinical signs are being reported.  A minimum of 28 days should elapse without any additional illness before individual horses are sampled and tested for virus.  A negative nasal swab PCR test is an indicator that the horse is no longer shedding virus.

An individual who boards a horse at the stable and also has four horses at their home reported that a pony on the home premises experienced neurologic signs of disease, was subsequently euthanized, and tested positive for EHV-1.  It is believed that the horse owner may have inadvertently transferred the virus from the affected stable to their home premises.

On Friday May 8, the Bureau of Animal Health and Welfare was notified that two horses located in a stable in Northeast Illinois tested positive for EHV-1 via the nasal swab PCR test.  Additional horses at the same stable had exhibited fevers throughout the week of May 4.  Three horses have exhibited neurologic signs of disease and two of those horses have been euthanized.  All horses on the premises have been restricted to the stable and are being monitored daily for signs of disease.  Stable personnel have been instructed to eliminate direct contact between horses as much as possible and to segregate sick horses from healthy horses as well as limit personnel entering the barn.  The stable manager has implemented enhanced cleaning and disinfection measures to help decrease the possibility of exposure.  A source of the initial exposure has not been identified.

It was also reported to the Bureau that several horses from this stable attended equine events on or about April 25th and on May 2nd.  These venues have been contacted and are implementing steps to reduce the chances of additional exposures.

Horse owners need to be mindful that most horses are exposed to one or more strains of EHV at a very young age.  Periods of high stress or additional exposure may cause an animal to exhibit clinical signs of disease.  Occasionally, the disease is exhibited as a serious neurologic disease.  Owners should consult with their veterinarian when deciding whether or not to attend an equine event as anytime horses are commingled there is the opportunity for exposure.

United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) states, the incubation period of EHV-1 is 1-10 days; typically signs are seen within 1-3 days. 
Viral shedding occurs for 7-10 days, but can occur up to 28 days from the onset of signs. 

The neurologic signs include ataxia, urinary bladder atony and reduced tail tone. In severe cases, horses will be unable to stand; these cases have a very poor prognosis. Foals are rarely affected with the neurologic form of EHV-1, and no sex predilection is seen. Treatment is supportive and tailored to the specific case. 

Once a horse is infected, it should be quarantined.  USDA recommends monitoring of all exposed horses for at least 7 days. During the isolation period, it is recommended to discontinue or reduce any strenuous training or exercise for exposed horses. 

All exposed horses should have rectal temperatures taken twice daily (8-12 hours apart) and recorded in a log for at least 7 days after the date of potential exposure. Horses whose rectal temperature registers higher than 101.5 degrees Fahrenheit are considered to be febrile. All horses on the premises should also be monitored for neurologic signs (ataxia, posterior incoordination, weakness, recumbency with inability to rise, circling, head pressing, head tilt, bladder atony) during the home quarantine period. Central nervous system signs, such as posterior incoordination, weakness, recumbency with inability to rise, and bladder atony are most common in EHM affected horses. 

More info:

Health Alert: Equine Infectious Anemia

On Thursday May 7, the Bureau of Animal Health and Welfare received confirmation that a horse stabled in Edgar County has tested positive for Equine Infectious Anemia.  The horse has been quarantined to the premises, and arrangements are being made for the disposition of the infected animal.  In addition, all other equine on the premises will be tested.  Bureau personnel will be conducting area surveillance testing of horses within a 1.5 mile radius of the quarantined premises.  If additional infected animals are disclosed, the surveillance area will be expanded.

History provided by the owner indicates that the infected horse has not been tested in recent years and has not been moved from the premises within the past couple of years.

Horse owners are reminded that Equine Infectious Anemia can be transferred via contact with infected blood.  Owners are encouraged to use appropriate insect control on animals and in and around buildings to decrease the possibility of exposure to biting insects.  The sharing of needles between horses should always be avoided and equipment such as dental floats and bits should be properly disinfected before being used on other horses.

Owners should consult their veterinarian regarding appropriate disease prevention protocols for Equine Infectious Anemia and other diseases that may affect equine.


Avian Influenza Information and Biosecurity Measures:


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PEDV Reporting and Herd Management Plan Information and Requirements





PEDV General Information

The National Pork Board has provided valuable information regarding Porcine Epidemic Diarrhea Virus (PEDV) at the link below.

Stakeholders are encouraged to visit this link for information on biosecurity, research, and disease updates.



The American Association of Swine Veterinarians has provided timely information on PEDV disease updates, research, laboratory submission guidelines, fact sheets, and additional resources. These resources can be accessed at the the link below.



AASV PEDV Information