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[RC] FW: new Equine virus outbreak - Steph Teeter

I was asked to forward this to Ridecamp:

-----Original Message-----
From: Saret & JY TOLA [mailto:maintale@xxxxxxxx]
Sent: Thursday, January 23, 2003 11:37 AM
To: Hmmarchman@xxxxxxx
Subject: Fw: new Equine virus outbreak

Below is a report on the current Rhino out break. It may turn out that the 
killed form of the Rhino vaccine is not protective. A Modified Live Vaccine 
(Rhinomune) may be a better choice for vaccination this year. JKW               
At least 10 horses have died or have been euthanized at the University of 
Findlay (UF) in      
Findlay, Ohio, after battling a respiratory and neurologic illness. Preliminary 
chain reaction (PCR) tests completed on tissue samples from affected horses by 
the Ohio        
Department of Agriculture’s (ODA) Animal Disease Diagnostic Laboratory this 
morning came back  
as “presumptive positive” for equine herpesvirus type-1 (EHV-1). Officials 
from the veterinary 
services department at the University of Findlay and epidemiologists and 
scientists from The   
Ohio State University (OSU) are working together today to treat at least 11 
affected horses    
with supportive care and determine the source of infection. The presumptive 
findings from the  
PCR tests will be verified by gene sequence analysis, with assistance from Ohio 
State. The     
results will be available from ODA in two to three days.                        
The EHV-1 organism can cause three different forms of disease, including 
rhinopneumonitis (a   
respiratory disease of mostly young horses), abortions in pregnant mares, and a 
disease. Officials believe this strain, if confirmed as EHV-1, could be one 
that combines the  
respiratory and neurologic clinical signs. There are at least seven other 
strains of equine    
herpesviruses, named in order of their discovery. (See article #32 at 
www.TheHorse.com for     
more on herpesviruses.) The neurologic form of EHV-1 often is survivable with 
supportive care, 
but unfortunately once a horse is recumbent, it is difficult to nurse the horse 
back to        
According to Mark Anthony, communications director for the ODA in Reynoldsburg, 
Ohio, gross    
lesions reported by OSU on tissue samples (brain and spinal cord) obtained from 
a necropsy     
appeared to be consistent with EHV-1.                                           
“As of last night (Jan. 21), 10 had either died or been euthanized because of 
the disease,”    
said Anthony. “A necropsy was performed on at least one, and that was 
performed at The Ohio    
State University. It was from that necropsy that we obtained spinal cord and 
brain tissue      
samples which we tested.” PCR tests were conducted on a number of samples, 
and two—one blood   
sample and one nasal swab from affected horses—were presumptive positive for 
“We’re seeing respiratory symptoms before neurological disorders,” said 
Anthony. On Wednesday, 
Jan. 15, a number of horses had fevers of up to 105?F. A University of Findlay 
services staff member said that a few of these horses developed nasal 
discharge, became        
depressed, and were not eating. By Friday, Jan. 17, the more seriously affected 
horses showed  
neurological signs including toe-dragging and wobbling of the hind end. 
Eventually some of the 
animals went down and were unable to rise. Around 30 horses of the 130 exposed 
at the facility 
were showing some symptoms of the illness by Jan. 17.              
EHV is not considered a reportable disease in Ohio, so Ohio State and 
University of Findlay    
personnel are handling the disease investigation. Anthony said, “When there 
is an outbreak of  
a foreign animal disease or an infectious contagious disease on our reportable 
disease list,   
we are in charge of coordinating the investigation. That is not the case here. 
We are          
identifying the virus responsible for the outbreak." Three members of Ohio 
State’s faculty and 
staff in the Veterinary Preventive Medicine department have traveled to Findlay 
including one clinician familiar with neurological illness and one 
epidemiologist. A staff     
veterinarian from the Ohio Department of Agriculture is assisting.              
PCR tests are very specific, and according to Anthony, other possible causes of 
the clinical   
signs such as Eastern equine encephalomyelitis (EEE) and Venezuelan equine 
(VEE), which are both reportable diseases in Ohio, have been all but ruled out. 
Bev Byrum, DVM, PhD, Lab Director at the Animal Disease Diagnostic Laboratory, 
said, "PCR      
technology allows us to work quickly in outbreaks like this to identify the 
agent causing the  
infection. In this case, we’ll probably know definitively in a couple more 
days. Under our     
previous standard testing procedures for growing and isolating a virus we’d 
be looking at two  
weeks minimum before we got a confirmed finding.”                             
The source of the disease is currently unknown. A veterinary services staff 
member at Findlay 
said a new semester began at the university in early January, with 
student-owned and school    
horses arriving Jan. 4 from all over the state of Ohio. It is unclear whether 
any of the       
horses were imported previously from Europe, where the neurological form of 
equine herpesvirus 
is seen more frequently than in the United States.                              
“The horses in question were reported to us to have been vaccinated,” said 
Anthony. The VS     
staff member confirmed that vaccinations, including influenza and 
rhinopneumonitis, were given 
properly. A negative Coggins test and strangles vaccination also are required 
for horses       
arriving on the university’s premises. The natural inclination of horse 
owners would be to ask 
why horses were infected with this disease if they were current on their 
Veterinarians have said in the past that no vaccine manufacturer has made a 
vaccine that       
guarantees that it will prevent the neurological form of EHV-1 from occurring, 
and that no     
vaccine is 100% effective.            
A strict self-imposed quarantine is in effect for the English riding facility 
where the        
outbreak occurred, and area horse owners have been advised to quarantine their 
horses. It is   
not clear how officials will be handling carcass disposal, but Anthony assured 
that the state  
of Ohio has specific guidelines for proper management of diseased carcasses.    

I hope this will explain the outbreak!

Frank M. Andrews, DVM, MS, DACVIM
Professor and Section Chief
Large Animal Medicine
College of Veterinary Medicine
The University of Tennessee
2407 River Drive
Knoxville, TN 37996
Phone: (865) 974-5701, 974-5764
Fax:     865-974-5773
email: fandrews@xxxxxxx

J.K.Waldsmith, D.V.M.
The Equine Center
4850 Davenport Creek Road
San Luis Obispo, CA. 93401
(805) 541- 6367, fax 541-3897 

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