First Detection of EHDV-6 in Ohio Deer
Melanie Prarat, MS, ADDL Central Receiving Section Head
EHD is a viral infection (genus Orbivirus, family Reoviridae) caused by epizootic hemorrhagic disease virus (EHDV) that is primarily transmitted by biting midges (genus Culicoides) to several species of cervids, especially white tailed deer. Major geographic expansion of EHDV has occurred during the past 40 years, associated with increasing frequency of large-scale outbreaks. Typically, outbreaks are caused by EHDV-2 in Ohio in the late summer and early fall. Occasionally, EHDV-1 has also been detected in Ohio in the past. In 2006, the exotic EHDV-6 was first detected and has been found in the central and eastern US. In September, outbreaks of EHD virus have been suspected in the captive and wild deer population. So far, eight samples have been positive for EHDV. Among them, four samples from four different counties were positive for EHDV-6. This is the first report of EHDV-6 in Ohio. In addition to EHDV-6, EHDV-2 has also been detected from samples submitted to our laboratory, which means that both strains of EHD viruses are currently circulating in the Ohio deer population and contribute to the outbreaks. Captive deer that are vaccinated against EHD-2 are not likely protected against EHD-6 virus. The following map illustrates which counties have produced EHDV-positive samples in 2020:
Sporadic clinical cases and outbreaks of EHD have also been reported in other cervids (mule deer and elk), cattle, bison, yaks, bighorn sheep, and pronghorn antelope, although most infections in these species seem to be subclinical. Deer infected with EHD can show little or no clinical signs (peracute illness) and are found dead, while in other infected animals the disease may linger for weeks and the deer may have fevers, anorexia, lethargy, weakness, lameness, and respiratory distress. The head and neck may swell and there may be ulcerations / erosions of the oral cavity with excessive salivation and nasal discharge. Diarrhea and severe dehydration and weight loss may occur if the animal survives the acute phase of the disease. The deer may show no fear of humans and often can be found near or in bodies of water due to fever and dehydration. More information about EHD.
EHDV does not infect humans.
ADDL Participates in NAHLN ASF Exercise
Anne Parkinson, BS, ADDL Serology Section Head
The ADDL was a participant in an African Swine Fever (ASF) exercise sponsored by the National Animal Health Laboratory Network (NAHLN) on September 15th and 16th, 2020.
 The purpose of the functional exercise was to follow the protocol for emergency test validation during an animal disease event in Ohio. Using African Swine Fever (ASF) as the target, laboratories were asked to submit a request for a deviation away from approved sample types and standard ASF extraction and PCR test methods in order to test swine oral fluids. Currently, oral fluids are not an approved sample type for the detection of ASF in swine. The request for deviation was then followed by players from the ADDL, the NAHLN, the National Veterinary Services Laboratory (NVSL), and the Foreign Animal Disease Diagnostic Laboratory (FADDL). To complete the emergency test validation, the exercise concluded with a successful notification from the NAHLN to deviate from the standard protocols and approval to test oral fluids during an outbreak of ASF in Ohio.
Updated Diagnostic Plans
Lauren Cain, RVT, MS, ADDL Veterinary Pathology Assistant
 The ADDL has updated their Diagnostic Plans (previously referred to as “diagnostic panels”) to provide guidance for appropriate diagnostic test selection. Enteric, Respiratory, and Abortion Plans are available for multiple species; see the ADDL website for detailed descriptions of included tests and required samples.
Notably, antibiotic susceptibility testing (AST) is no longer included by default in testing plans. Please be sure to mark the box on the submission form authorizing AST if desired to prevent delay in reporting of results. Requests for AST received more than 3 days after reporting of culture results will result in the incurrence of additional fees associated with repeated cultures.
All tests may still be ordered individually as needed, and Diagnostic Plans may be customized as the attending veterinarian and veterinary pathologist see fit. For more information, please call 614-728-6220 or e-mail animal@agri.ohio.gov.
Upcoming Holiday
The Ohio ADDL will be closed on Monday, October 12, 2020 in observance of Columbus Day.
For additional information and resources, please visit our website. If you need to contact us regarding an urgent matter, please use our after hours phone number: (888) 456-3405.
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