Ibex-associated malignant catarrhal fever in duikers (Cephalophus spp)

Authors: CARVALLO, FRANCISCO - University Of California, Davis; UZAL, FRANCISCO - University Of California, Davis; MOORE, JANET - University Of California, Davis; JACKSON, KENNETH - University Of California, Davis; NYAOKE, AKINYI - University Of California, Davis; NAPLES, LISA - California Animal Health Laboratory; DAVIS-POWELL, JORDAN - California Animal Health Laboratory; STADLER, CYNTHIA - California Animal Health Laboratory; BOREN, BRANDON - California Animal Health Laboratory; Cunha, Cristina; LI, HONG - Retired ARS Employee; PESAVENTO, PATRICIA - University Of California, Davis

Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2020
Publication Date: 5/14/2020
Citation: Carvallo, F.R., Uzal, F.A., Moore, J.D., Jackson, K., Nyaoke, A.C., Naples, L., Davis-Powell, J., Stadler, C.K., Boren, B.A., Cunha, C.W., Li, H., Pesavento, P.A. 2020. Ibex-associated malignant catarrhal fever in duikers (Cephalophus spp). Veterinary Pathology. 57(4):577-581. https://doi.org/10.1177/0300985820918313.
DOI: https://doi.org/10.1177/0300985820918313

Interpretive Summary: Malignant catarrhal fever (MCF) in zoos and private collections occurs in various combination of reservoirs and susceptible species. To better control the disease in these settings, it is critical that cases are properly diagnosed and the source of virus identified. Here we describe for the first time an outbreak of ibex-associated MCF in duikers housed in a single zoological collection. Presumptive diagnosis was based on epidemiological, clinical and pathological manifestations and specific molecular techniques (PCR and in situ hybridization) were used to confirming the final diagnosis of ibex-associated MCF in this group of duikers. Identical viral sequences were also detected in blood and tissues of seven ibexes (Capra ibex) housed in a separate enclosure 35 meters away, confirming the source of the virus that infected the duikers. Besides adding duikers to the list of species susceptible to ibex-associated MCF, this report describes in details the disease pathology and serves as a reference for prevention of future cases.

Technical Abstract: Eight duikers, representing three different species co-housed in a single zoological collection, died in a 10-month period. Black, red-flanked and yellow-backed duikers were affected, appearing clinically with a combination of anorexia, diarrhea, ataxia, tremors, and/or stupor, followed by death within 72 hours of onset of clinical signs. Consistent gross findings were generalized lymphoadenomegaly, peritoneal and pleural effusion, and pulmonary ecchymoses. Dense infiltration of lymphocytes and arteritis affected numerous tissues in most animals. Ibex-associated malignant catarrhal fever (MCF) viral DNA was detected in all cases by PCR and in situ hybridization. Identical ibex-associated MCFV sequence was detected in spleen of ibex (Capra ibex) housed in a separate enclosure 35 meters away.