Canine Distemper Virus in Endangered Species: Species Jump, Clinical Variations, and Vaccination

Abstract

Canine morbillivirus (Canine distemper virus, CDV) is the cause of distemper in a large number of different species, some of which are endangered. The clinical outcome associated with infection is variable and based on many factors, including the host species, the immune response of the individual animal to the infection, and variation in virus tropism and virulence. Unfortunately, the viral characteristics associated with virulence versus attenuation are not fully characterized, nor are the specific mutations that allow this virus to easily move and adapt from one species to another. Due to its wide host range, this virus is difficult to manage in ecosystems that are home to endangered species. Vaccination of the domestic dog, historically considered the reservoir species for this virus, at dog-wildlife interfaces has failed to control virus spread. CDV appears to be maintained by a metareservoir rather than a single species, requiring the need to vaccinate the wildlife species at risk. This is controversial, and there is a lack of a safe, effective vaccine for nondomestic species. This review focuses on topics that are paramount to protecting endangered species from a stochastic event, such as a CDV outbreak, that could lead to extinction.

A Bacterium-like Particle Vaccine Displaying Envelope Proteins of Canine Distemper Virus Can Induce Immune Responses in Mice and Dogs

“…The CDV-inactivated vaccines have advantages of high safety and simple preparation, but the antibody titer is not high and their protection period is short. The replication of attenuated vaccines in immunized animals may lead to reverse viral virulence, resulting in death and the spread of the virus by immunized animals [ 27 ]. Based on these considerations, we conducted research on CDV vaccines specifically for giant pandas.…”

Biomolecular Analysis of Canine Distemper Virus Strains in Two Domestic Ferrets (Mustela putorius furo)

“…Variations in the H gene sequence have been related to host species shift or the virulence of CDV strains [ 55 , 56 , 57 ]. Variations in specific amino acid residues of the SLAM-binding region, particularly at the 530 and 549 residues, have been associated with distemper adaptation in non-dog hosts [ 58 ]. The amino acid substitution of tyrosine (Y) with histidine (H) at site 549 has been associated with an adaptation of CDV from dogs to non-domestic hosts [ 59 ].…”

Disease threats to tigers and their prey

“…Canine distemper is caused by an enveloped, single-stranded RNA virus in the genus Morbillivirus (giving rise to its contemporary common name, canine morbillivirus). The viral envelope reduces environmental stability (particularly in warmer temperatures), limiting opportunities for indirect transmission (Wilkes, 2023). However, CDV is readily transmitted during direct contact, via inhalation of aerosolized respiratory droplets or possibly during predation of infected individuals (Gilbert et al, 2020).…”