Dolphin morbillivirus (DMV) is a pathogen of great concern in free-ranging cetaceans. Confirmation and staging of morbillivirus infections rely on histology and immunohistochemistry (IHC), following molecular detection. As at the present time no specific antibodies (Abs) against DMV are available, two heterologous Abs have been used worldwide for the examinations of morbillivirus infections of cetaceans. One is a monoclonal Ab (MoAb) prepared against the N protein of canine distemper virus (CDV), whereas the other is a polyclonal Ab raised in rabbits against rinderpest virus (RPV). Both Abs are known to show cross-reactivity with DMV. In this study we compared the labelling quality and the neuroanatomical distribution of staining with these two Abs by means of IHC analysis. To this end, serial sections of the target organs from ten free-ranging stranded cetaceans, previously diagnosed as being infected with DMV by PCR and/or serology, were subjected to IHC. The brain, lungs and lymph nodes of one animal were found to be positive with both Abs. From two other animals, the brain and the spleen, respectively, tested positive only with the polyclonal Ab. In the positive brain tissues, multifocal immunostaining was observed, with similar staining location and extent, with the two antibodies tested. Our results suggest that the polyclonal anti-RPV Ab might have a stronger binding activity to DMV than the anti-CDV MoAb. Nevertheless, the elaboration and use of specific anti-DMV Abs might be essential to guarantee conclusive results in diagnostic and pathogenetic investigations.
Amude, A. M., Alfieri, A. F. and Alfieri, A. A. (2010): Use of immunohistochemistry and molecular assays such as RT-PCR for precise post mortem diagnosis of distemper-related encephalitis. In: Méndez-Vilas, A. (ed.) Current Research, Technology and Education Topics in Applied Microbiology and Microbial Biotechnology, Formatex, Spain. pp. 1539–1545.
Di Guardo, G., Proietto, U., Di Francesco, C. E., Marsilio, F., Zaccaroni, A., Scaravelli, D., Mignone, W., Garibaldi, F., Kennedy, S., Forster, F., Iulini, B., Bozzetta, E. and Casalone, C. (2010): Cerebral toxoplasmosis in striped dolphins (Stenella coeruleoalba) stranded along the Ligurian Sea coast of Italy. Vet. Pathol. 47, 245–253.
Díaz-Delgado, J., Groch, K. R., Sierra, E., Sacchini, S., Zucca, D., Quesada-Canales, Ó., Arbelo, M., Fernández, A., Santos, E., Ikeda, J., Carvalho, R., Azevedo, A. F., Lailson-Brito, J. Jr., Flach, L., Ressio, R., Kanamura, C. T., Sansone, M., Favero, C., Porter, B. F., Centelleghe, C., Mazzariol, S., Di Renzo, L., Di Francesco, G., Di Guardo, G. and Catão- Dias, J. L. (2019): Comparative histopathologic and viral immunohistochemical studies on CeMV infection among Western Mediterranean, Northeast-Central, and Southwestern Atlantic cetaceans. PloS One 14, 1–21.
Díaz-Delgado, J., Sierra, E., Vela, A. I., Arbelo, M., Zucca, D., Groch, K. R. and Fernández, A. (2017): Coinfection by Streptococcus phocae and cetacean morbillivirus in a short-beaked common dolphin Delphinus delphis. Dis. Aquat. Org. 124, 247–252.
Geraci, J. R. and Lounsbury, V. J. (2005): Marine Mammals Ashore: A Field Guide for Strandings. 2nd ed. National Aquarium in Baltimore, Baltimore, MD. 382 pp.
Giorda, F., Ballardini, M., Di Guardo, G., Pintore, M. D., Grattarola, C., Iulini, B., Mignone, W., Goria, M., Serracca, L., Varello, K., Dondo, A., Acutis, P. L., Garibaldi, F., Scaglione, F. E., Gustinelli, A., Mazzariol, S., Di Francesco, C. E., Tittarelli, C., Casalone, C. and Pautasso, A. (2017): Postmortem findings in cetaceans found stranded in the Pelagos sanctuary, Italy, 2007–14. J. Wildl. Dis. 53, 795–803.
Pautasso, A., Iulini, B., Grattarola, C., Giorda, F., Goria, M., Peletto, S., Masoero, L., Mignone, W., Varello, K., Petrella, A., Carbone, A., Pintore, A., Denurra, D., Scholl, F., Cersini, A., Puleio, R., Purpari, G., Lucifora, G., Fusco, G., Di Guardo, G., Mazzariol, S. and Casalone C. (2019): Novel dolphin morbillivirus (DMV) outbreak among Mediterranean striped dolphins Stenella coeruleoalba in Italian waters. Dis. Aquat. Org. 132, 215–220.
Peletto, S., Caruso, C., Cerutti, F., Modesto, P., Biolatti, C. Pautasso, A., Grattarola, C., Giorda, F., Mazzariol, S., Mignone, W., Masoero, L., Casalone, C. and Acutis, P. L. (2018): Efficient isolation on Vero.DogSLAMtag cells and full genome characterization of Dolphin Morbillivirus (DMV) by next generation sequencing. Sci. Rep. 8, 1–8.
Sergeant, E. S. G. (2018): Epitools Epidemiological Calculators, Ausvet Pty Ltd. Available from: http://epitools.ausvet.com.au.
Smedley, R. C., Patterson, J. S., Miller, R., Massey, J. P., Wise, A. G., Maes, R. K., Wu, P., Kaneene, J. B. and Kiupel, M. (2007): Sensitivity and specificity of monoclonal and polyclonal immunohistochemical staining for West Nile virus in various organs from American crows (Corvus brachyrhynchos). BMC Infect. Dis. 7, 1–9.
Stanton, J. B., Brown, C. C., Poet, S., Lipscomb, T. P., Saliki, J. and Frasca, S., Jr. (2004): Retrospective differentiation of canine distemper virus and phocine distemper virus in phocids. J. Wildl. Dis. 40, 53–59.
Van Bressem, M. F., Duignan, P. J., Banyard, A., Barbieri, M., Colegrove, K. M., De Guise, S., Di Guardo, G., Dobson, A., Domingo, M., Fauquier, D., Fernandez, A., Goldstein, T., Grenfell, B., Groch, K. R., Gulland, F., Jensen, B. A., Jepson, P. D., Hall, A., Kuiken, T., Mazzariol, S., Morris, S. E., Nielsen, O., Raga, J. A., Rowles, T. K., Saliki, J., Sierra, E., Stephens, N., Stone, B., Tomo, I., Wang, J., Waltzek, T. and Wellehan, J. F. (2014): Cetacean morbillivirus: current knowledge and future directions. Viruses 6, 5145–5181.
Verna, F., Giorda, F., Miceli, I., Rizzo, G., Pautasso, A., Romano, A., Iulini, B., Pintore, M. D., Mignone, W., Grattarola, C., Bozzetta, E., Varello, K., Dondo, A., Casalone, C. and Goria, M. (2017): Detection of morbillivirus infection by RT-PCR RFLP analysis in cetaceans and carnivores. J. Virol. Methods 247, 22–27.
Yang, W. C., Pang, V. F., Jeng, C. R., Chou, L. S. and Chueh, L. L. (2006): Morbilliviral infection in a pygmy sperm whale (Kogia breviceps) from Taiwanese waters. Vet. Microbiol. 116, 69–76.