Canine distemper outbreak by natural infection in a group of vaccinated
maned wolves in captivity
Abstract
Canine morbillivirus, also known as canine distemper virus (CDV) is one
of the most important infectious diseases threat to the health and
conservation of free ranging and captive wild carnivores. CDV
vaccination using recombinant vaccines has been recommended for maned
wolf (Chrisosyon brachyurus) after the failure of modified live vaccines
that induced disease in vaccinated animals. However, there has been a
lack of systematic evaluation about the response of this preventive
protocol in zoo carnivores due to ethical reasons that do not approve
vaccination trials with challenge in that species. Here we report a CDV
outbreak in a captive population of maned wolf with an index case that
was previously vaccinated with a recombinant vaccine. Five juveniles and
one adult from a group of seven maned wolves housed in an outdoor
exhibit died in April-May 2013 in a zoo in the Metropolitan Region,
Chile. Clinical signs ranged from lethargy to digestive and respiratory
signs. Diagnosis of CDV was confirmed by histopathology, antibody assays
and viral molecular detection and characterization. The phylogenetic
analyses of the nucleotide sequence of H gene of the CDV genome
identified in the two positive samples suggest a close relation with the
lineage Europe 1, commonly found South America and Chile. CDV infections
in maned wolf have not been previously characterized. To the authors
best knowledge is the first report of the clinical presentation of CDV
in a canine species previously inmmunized with a recombinant vaccine.
Further research will be necessary to understand the impact of CDV in
wild maned wolf populations and new protocols (with boosters) that could
improve the effectiveness of the recombinant vaccine against CDV in wild
carnivores.