SHIC Acts on Diagnosis of Novel Morbillivirus in Pigs

The Iowa State University Veterinary Diagnostic Lab (ISU VDL) received 22 porcine fetuses from six litters originating in Mexico in the spring of 2020. After extensive testing for known pathogens, metagenomics sequencing identified a new virus in the genus of Morbillivirus. ISU VDL staff named it porcine morbillivirus (PoMV) and conducted an initial study providing some insight into the outbreak. Subsequently, these researchers sought funds to isolate PoMV and determine presence/incidence of the virus in the US swine population. The Swine Health Information Center (SHIC) Monitoring and Analysis Working Group reviewed and approved the ISU VDL funding request for further study on PoMV as part of its ongoing mission to protect and enhance US swine herd health with a focus on emerging and transboundary swine disease prevention, preparedness, and response.

PoMV was determined to be the cause of fetal death, encephalitis, and placentitis among the six swine litters from Mexico. Of the 22 fetuses submitted to the ISU VDL, there was one neonatal mortality, three stillbirths, fourteen mummified fetuses, and four fetuses with moderate autolysis.

In a peer-reviewed paper on the novel PoMV finding and initial study, ISU researcher Ganwu Li and colleagues wrote, "Morbilliviruses are highly contagious pathogens. The Morbillivirus genus includes measles virus, canine distemper virus (CDV), phocine distemper virus (PDV), peste des petits ruminants virus, rinderpest virus, and feline morbillivirus." Their diagnostic work showed PoMV is most closely related to CDV and PDV. They also reported PoMV viral RNA was detected in neurons, respiratory epithelium, and lymphocytes.

While the initial study by ISU researchers provided essential information on this newly discovered pathogen, they acknowledge much must yet be learned. In the SHIC-funded work, the opportunity for studies of viral pathogenicity, pathogenesis, and vaccine development will all be made possible. Information from the proposed epidemiology study will aid in detection and response to any future outbreaks of PoMV.