Neurological disease, neoplasms, and novel gammaherpesviruses in critically endangered captive european minks (Mustela lutreola)
Carlos SacristánMuseo del Jade
Olga Nicolas de Francisco, Fernando Esperón, Carles Juan-Sallés, Ana Carolina Ewbank, Carlos G. das Neves, Elena Neves, Neil Anderson, Carlos Sacristán
The European mink (Mustela lutreola) is a riparian mustelid, considered one of the most endangered carnivores in the world. Four cases of incoordination and rear limb weakness were observed in captive European minks housed in a breeding center in northeastern Spain. Blood hematology and biochemistry were performed in the 13 animals (12 apparently healthy and one ill). Gross (n=11) and histopathological (n=4) examinations were performed. Electron microscopy was performed in a mink with neural lymphoma and inclusion bodies. Additionally, 141 samples of swabs (oral, conjunctival, anal), feces and tissues from 23 animals were analyzed for herpesvirus (HV) using a pan-HV PCR assay. The ill mink presented anemia, lymphopenia and azotemia, while the remaining animals presented hematological and biochemical values within the parameters for other Mustelidae species. Several neoplasms, including lymphoma (n=2), pulmonary adenocarcinoma (n=1), and biliary (n=1) and preputial (n=1) cystadenoma, as well as other lesions (e.g., axonal degeneration [n=2]), were observed in some infected European minks. Two different gammaherpesviruses were identified in four animals (17.3%), and could represent novel HV species, tentatively named Mustelid gammaherpesvirus-2 (MUGHV-2) and MuGHV-3. This is the first description of neoplasms and gammaherpesviruses in European minks. The pathological (inclusion bodies and syncytia), ultraestructural (viral particles) and PCR findings (MuGHV-2) in one lymphoma case strongly suggest a potential role for this novel gammaherpesvirus in its pathogenesis, as it has been reported in other HV-infected species with lymphoproliferative disease. The occurrence of neural lymphoma with intralesional syncytia and herpesviral inclusions is, however, unique among mammals. Additionally, the lymphoma, spongiosis and axonal degeneration affecting the central and peripheral nervous system observed in some of these animals may explain the reported neurological clinical signs. Further research is warranted to elucidate the role of gammaherpesviruses as potential cofactors of neoplasms in European mink and their epidemiology in the wild population.