First report of Rabbit Hemorrhagic Disease Type 2 In US found in Ohio
Dr. Jeff Hayes, MS, DVM, ADDL Pathology Section Head
The first report of Rabbit Hemorrhagic Disease (RHD) type 2 in the United States was detected in one of five pet rabbits in Medina County, Ohio this fall. The first announcement of RHD2 was made on September 21, 2018, by Dr. John Clifford, Official Delegate, Chief Trade Advisor, Animal and Plant Health Inspection Service, United States Department of Agriculture to the World Organization of Animal Health (OIE). Formalin-fixed tissue examined by a private pathology laboratory had microscopic changes of severe widespread hepatic necrosis that were consistent with RHD infection. The office of the State Veterinarian was notified of the pathology report, and an investigation identified frozen liver tissue retained by the submitting veterinarian. This tissue was forwarded to the Foreign Animal Disease Diagnostic Laboratory (FADDL) at Plum Island (New York) and was found on 9/20/2018 to be positive for nucleic acid of RHD2 virus and not for that of RHD type 1 virus.
As a follow up, ODA field staff and the ADDL worked closely with Division of Wildlife staff to harvest and test several cottontail rabbits from the area. None of the harvested rabbits had gross or microscopic lesions of RHD infection, however tissues from those rabbits were submitted to FADDL for testing. None of the six wild cottontails were found to have RHD2 nucleic acid or antigen in liver tissue, The last surviving pet rabbit at the index case premise was also negative for evidence of RHD infection. It is unknown how this virus gained entry to the barn where the affected pet rabbits were kept. Investigations of more than a dozen other rabbits from around Ohio that died acutely have not detected any additional cases of this highly infectious and contagious calicivirus. The virus may be transmitted orally by secretions and excretions including oral, nasal and pharyngeal secretions, urine and feces; transmission by insects is considered significant in the transmission among wild rabbits. The incubation period may be as short as 1-3 days, with death usually occurring within 12-36 hours after onset of a fever.
Rabbit owners are encouraged to use the highest levels of biosecurity possible to avoid entry of this virus (and other pathogens) into their rabbitries. No vaccine against RHD is currently available in the USA. Veterinarians are encouraged to contact the ODA (614-728-6220) to report outbreaks of acute deaths in rabbits with high mortality rates while additional information is learned about the status of RHD virus in Ohio.
 Control of Brucella canis in high volume dog breeders in Ohio
Dr. Yan Zhang, DVM, PhD, DACVM, ADDL Virology Section Head
Dr. Melissa Simmerman, DVM, ODA Animal Health Veterinarian
Canine brucellosis, caused by Brucella canis, is a significant reproductive disease in breeding dogs worldwide. The bacterium is a Gram-negative, intracellular coccobacillus. B. canis is a zoonotic concern for human infection. In 2015, canine brucellosis in high volume dog breeder (HVDB) facilities became a regulatory reportable disease in Ohio. As of September 28, 2018, a HVDB is defined as a facility that keeps, houses, and maintains six or more breeding dogs and does at least one of the following: 1) Sells five or more adult dogs or puppies in any calendar year to dog brokers or pet stores; 2) Sells forty or more puppies in any calendar year to the public; or 3) Keeps, houses, and maintains, at any given time in a calendar year, more than forty puppies that are under four months of age, that have been bred on the premises of the establishment, and that have been primarily kept, housed, and maintained from birth on the premises of the establishment.
To support the program, ADDL validated a testing scheme based on two serologic assays for the diagnosis of canine brucellosis. The testing scheme uses a commercially available, indirect fluorescent antibody (IFA) as a screening test followed by a tube agglutination test (TAT) for confirmation of IFA-positive dogs. Since 2015, the ADDL has completed over 40,000 serologic tests. To date 171 dogs have tested positive by the IFA and 135 dogs were confirmed to be positive by the TAT. A total of 33 HVDB facilities have been quarantined until animals retested negative. The number of B. canis-infected dogs has declined quickly in HVDB facilities in Ohio since the implementation of the program. In 2018, one licensed HVDB facility had two dogs test positive for B. canis in a whole kennel test; the two dogs that tested positive were removed from that kennel and a follow up test conducted 60 days later on the remaining dogs in the kennel were all negative, indicating successful control of the disease within the facility.
For more information about canine brucellosis and testing options offered at ADDL, please visit our Brucellosis Resource Page.
 CWD Outreach
ADDL Pathology staff conduct CWD sample collection training
On Thursday, October, 26. 2018, Dr. Jeff Hayes presented a seminar to ten veterinarians and hunting preserve managers regarding sample collection for tissues needed to test for chronic wasting disease (CWD) in white-tailed-deer and other cervids by immunohistochemistry (IHC). As a NAHLN-approved laboratory, the ADDL performs IHC on thousands of samples from captive deer each year to determine if PrP-res, a molecular marker for CWD infection, is present in sections of brainstem and certain lymph nodes. The seminar followed a wet lab in which lab participants were trained by Drs. Craig Sarver, Jeff Hayes and ODA field veterinarian Dr. Dave Frew how to collect retropharyngeal lymph nodes and obex samples, as well as practical details including sample handling, shipping, paperwork and disinfection. If you are interested in participating in the ODA Captive White-Tailed-Deer Herd Certification Program, contact Christi Clevenger at 614-728-6220 or by email at Christi.Clevenger@Agri.ohio.gov.
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 ADDL Staff Presentations at the 61st Annual AAVLD Meeting
Melanie Prarat, MS, ADDL Virology Section
Drs. Bev Byrum, Jing Cui, and Yan Zhang, as well as Melanie Prarat, represented the ADDL at the 61st Annual Meeting of the American Association of Veterinary Laboratory Diagnosticians in Kansas City, Missouri from October 17-21. The following presentations were made by ADDL during the meeting:
Characterization of Influenza A Virus in Ohio Pig Farms Using Next Generation Sequencing Technology
M. Prarat, B. Byrum, Y. Zhang
Case Investigation: Multi-State Outbreak of Human Campylobacteriosis Linked to Pet Store Puppies
M. Prarat, J. Cui, R. Reimschuessel, M. Weisner, S. Young, J. Jones, O. Ceric, S. Nemser, B. Byrum, Y. Zhang
(For more information, see the MMWR article about the outbreak, published in September 2018)
Control and Eradication of Brucella canis in Large Volume Dog Breeders in Ohio
J. Cui, J. Hayes, M. Weisner, D. Summers, B. Byrum, Y. Zhang
(Visit our Canine Brucellosis Resource Page for more information about this disease and diagnostic testing offered at ADDL)
A Scheme for Typing of Helcococcus ovis Using Next Generation Sequencing
J. Cui, M. Prarat, D. Jurkovic, M. Weisner, Y. Zhang
The lab also presented a poster titled "Detection and Characterization of a Bufavirus in Pigs Using Next Generation Sequencing Technology", by M. Prarat, Q. Wang (Ohio State University), J. Cui and Y. Zhang.
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 The ADDL will be CLOSED on November 12 (Veteran's Day) and November 22 (Thanksgiving). If you need to contact us regarding an urgent matter, please use our after hours phone number: (888) 456-3405.
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