First identification and characterization of ovine gammaherpesvirus type 2 in horses and artiodactyla from an outbreak of malignant catarrhal fever in Mexico

• Published in: PloS one Vol. 18; no. 9; p. e0290309
• Main Authors: Madrigal-Valencia, Tania Lucia, Saavedra-Montañez, Manuel, Pérez-Torres, Armando, Hernández, Jesús, Segalés, Joaquim, Hernández, Yesmín Domínguez, Candanosa-Aranda, Irma Eugenia, Pérez-Guiot, Alfredo, Ramírez-Mendoza, Humberto
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 01-09-2023; Public Library of Science (PLoS)
• Subjects: Animals; Antibodies; Artiodactyla; Biology and Life Sciences; Buffy coat; Cattle; Cell culture; Cornea; Cytoplasm; Deer; Disease susceptibility; Diseases; Fever; Food consumption; Foot & mouth disease; Fractions; Health aspects; Horses; Immunocytochemistry; Immunofluorescence; Immunohistochemistry; Immunoproliferative diseases; Inclusion bodies; Lymphatic system; Lymphocytes; Macavirus; Malignant catarrhal fever; Medicine and Health Sciences; Nucleotides; Opacity; Outbreaks; Polymerase chain reaction; Rabbits; Research and Analysis Methods; Sheep; Syncytia; Tongue; Ulcers; Ungulates; Vestibules; Viruses; Weight loss; Mexico; Brazil; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0290309

Ovine gammaherpesvirus 2 (OvHV-2), a member of the genus Macavirus, causes sheep-associated malignant catarrhal fever (SA-MCF), a fatal lymphoproliferative disease affecting a wide variety of ungulates in addition to horses. This study described an outbreak of SA-MCF in Mexico and the identification of the OvHV-2 virus in primary rabbit testis cultures through the generation of intranuclear inclusion bodies, syncytia, immunofluorescence (IF), immunocytochemistry (ICC), immunohistochemistry (IHC), endpoint polymerase chain reaction (PCR), and partial sequencing of the ORF75 gene. The animals involved in this outbreak showed mucogingival ulcers in the vestibule of the mouth and tongue, hypersalivation, corneal opacity, reduced food consumption, and weight loss of variable severity. These clinical signs and the histopathological findings suggested the diagnosis of SA-MCF. Buffy coat fractions from the anticoagulated blood samples of ill animals were collected and analyzed by PCR. Positive buffy coats were used to inoculate the primary cell cultures of rabbit testis to identify the virus. Small clusters of refractile cytomegalic cells, characteristic of viral cytopathic effects, were observed between 48 and 72 h post-infection. Furthermore, intranuclear acidophilic inclusion bodies (IBs) were identified in the inoculated primary culture cells, and the cytoplasm showed immunoreactivity with hyperimmune rabbit serum against OvHV-2. Moreover, in the liver histological sections from sick deer, immunoreactive juxtanuclear IBs were identified with the same rabbit hyperimmune serum. The obtained sequences were aligned with the OvHV-2 sequences reported in GenBank and revealed a nucleotide identity higher than 98%. Based on the evidence provided in this study, we conclude that the outbreak of SA-MCF in the municipality of Tequisquiapan in the state of Queretaro, Mexico, was caused by OvHV-2. This is the second study reporting that horses are susceptible to OvHV-2 infection and can develop SA-MCF. We identified for the first time in Mexico, the presence of OvHV-2 in buffy coats from horses and Artiodactyla.