Veterinary diagnostic laboratories have reported a low but concerning incidence of central nervous system (CNS) cases submitted over the last six months. Diagnosticians in the laboratories have agreed to report CNS-related cases to the Swine Health Information Center (SHIC). A case definition that triggers a report includes clinical symptoms of ataxia, muscle tremors or muscle weakness and CNS signs implicating brain, brain stem or spinal cord functional compromise. Included in the information are PCR results for sapelovirus, teschovirus, enterovirus or atypical pestivirus and a histology report consistent with viral encephalitis or myelitis. A full description of the guidelines for identifying and reporting these syndromes can be found by clicking here. [Source: Swine Health Information Center, March 22, 2017]
Case reports received show 10 to 15 percent morbidity and 100 percent case mortality. Average age of affected pigs has been 10 weeks (range 0.5 – 26 weeks). Clinical signs have included ataxia, muscle tremors, and muscle weakness possibly leading to paralysis.
Sapelovirus and/or teschovirus were detected in 12 of the 17 cases. You can learn more about both at the SHIC website – click here for the sapelovirus fact sheet and here for the teschovirus fact sheet. Two samples were negative by PCR for porcine sapelovirus, porcine teschovirus, porcine enterovirus and atypical porcine pestivirus. Access more information about a CNS syndrome case report by clicking here.
SHIC was also involved in a case study on sapelovirus which contains information helpful to practitioners who may be seeing CNS syndromes.
Porcine sapelovirus is a single stranded, positive-sense genomic RNA virus in the family of Picornaviridae, formerly known as porcine enterovirus serotype 8. Porcine enteroviruses were historically serotyped by virus-neutralization and divided in 13 serotypes. Based on modern molecular techniques and physiochemical properties these 13 serotypes are now subdivided as follows:
- Porcine enterovirus group I serotypes 1-7, 11-13 are assigned to the new genus Teschovirus as porcine teschovirus (PTV)
- Porcine enterovirus group II serotype 8 is assigned to genus Sapelovirus as porcine sapelovirus (PSV)
- Porcine enterovirus group III serotypes 9 and 10 remain as porcine enterovirus B (PEV-B).
Read the entire porcine sapelovirus case study and watch the videos of the clinical signs on the SHIC website by clicking here.
SHIC encourages practitioners to watch for neurologic cases and submit samples to a veterinary diagnostic lab for diagnosis. SHIC offers support for diagnostic fees if more investigation is needed after the initial diagnostics are done but were unrewarding. Find information on SHIC diagnostic fee support by clicking here.
The mission of the Swine Health Information Center is to protect and enhance the health of the United States swine herd through coordinated global disease monitoring, targeted research investments that minimize the impact of future disease threats, and analysis of swine health data. For more information, visit http://www.swinehealth.org or contact Dr. Paul Sundberg at psundberg@swinehealth.org.