A Canine Distemper Outbreak in Alaska: Diagnosis and Strain Characterization Using Sequence Analysis

Abstract

Abstract. Vaccination with modified-live vaccines has been very effective in reducing the incidence of canine distemper, a disease that can be devastating in unvaccinated populations. A diagnostic submission to the Animal Health Diagnostic Laboratory at Michigan State University, East Lansing, Michigan, involved a case in which several hundred dogs in an Alaskan town died in a suspected canine distemper outbreak. Cytoplasmic and intranuclear eosinophilic inclusion bodies, consistent with canine distemper virus (CDV) infection, were found in urinary bladder, spleen, lung, and salivary gland. Direct fluorescent antibody test gave results that could be considered positive for canine distemper. Because of the condition of the tissues received, the histopathology and fluorescent antibody-staining results were suggestive but not conclusive of CDV. In this study, immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR), and DNA sequencing were used to confirm the presence of canine distemper virus in these tissues and to perform molecular characterization of the virus. Immunohistochemistry showed the presence of the virus in spleen, lung, and salivary gland. Viral RNA was detected by RT-PCR in brain, spleen, liver, lung, and kidney, both with nucleoprotein and phosphoprotein (P)-gene-specific primers. Sequence alignment and phylogenetic analysis of a 540-bp P-gene fragment of the Alaskan strain with corresponding sequences of 2 vaccine and 7 wild-type CDV strains showed that the virus responsible for the outbreak was closely related to a virulent strain of distemper virus from Siberia.Canine distemper virus (CDV) is an enveloped negative-strand RNA virus classified under the genus Morbillivirus within the family of Paramxyoviridae. Canine distemper has a very broad host range, which includes Canidae, Mustelidea, Procyonidae, Ursidae, Viverridae, and Felidae. The clinical picture of CDV infection in dogs is considered to be dependent on virus strain characteristics, age and immune status of the affected animal, and environmental factors. When population immunity is high, many CDV infections are either clinically unapparent or result in a clinical picture that is relatively mild and may go unrecognized as distemper. When infection occurs in highly susceptible young animals, however, severe multisystemic disease can result. The time of onset of the immune response and, likely, also the virulence of the virus are critical factors in the extent of viral invasion of epithelial tissues and of the central nervous system. The degree and extent of the distemper-induced encephalomyelitis varies somewhat between the various strains of virulent virus. 2,3,5,12,13,15 A large number of dogs that were participating in a sled race in Kotzbue, Alaska, became ill with symptoms that were clinically consistent with canine distemper. Catarrh, mucopurulent nasal discharge, and neurological signs were noted in the affected animals. During the first week of this outbreak, approximately 200 Alaskan Huskies and other mixed-...

Phylogenetic Characterization of Canine Distemper Viruses Detected in Naturally Infected Dogs in North America

“…Furthermore, phylogenetic analysis of complete H and F gene sequences suggested that none of the strains detected were closely related to either known vaccine strains or lineages previously detected in the continental United States. Although CDV isolates detected in naturally occurring cases often group by geographical location following phylogenetic analysis (8,9,17,18,20,21,23,28), other studies have provided examples in which CDV strains do not group by broad geographical location (25,26,28), as shown for the cases studied here. Phylogenetic analyses of CDV P, F, and H gene nucleotide and amino acid sequences have been performed to study evolutionary relationships between CDV isolates and to find genetic variation among wild-type and CDV vaccine strains.…”

Soroprevalência das infecções por parvovírus, adenovírus, coronavírus canino e pelo vírus da cinomose em cães de Santa Maria, Rio Grande do Sul, Brasil

“…A enfermidade caracteriza-se por febre bifásica, pústulas abdominais, sinais sistêmicos e neurológicos, ocorrendo com maior freqüência em filhotes com três a seis meses de idade (MAES et al, 2003). A infecção pelo CDV possui distribuição mundial e surtos têm sido relatados na Europa (BLIXENKRONE-MÖLLER et al, 1993;EK-KOMMONEN et al, 1997) e nos Estados Unidos (PATRONEK et al, 1995;MAES et al, 2003). No Brasil, alguns relatos clínico-patológicos e sorológicos indicam a presença da infecção na população canina (HEADLEY & GRAÇA, 2000;SCHMIDT et al, 2004;SILVA et al, 2004).…”

Cinomose canina: revisão de literatura

“…(Freitas-Filho et al, 2014). Nenhum sinal clínico para esta enfermidade é classificado como patognomônico, e os sinais podem ocorrer de maneira sequencial, simultânea ou isolada (Maes et al, 2003;Greene e Appel, 2006;Garde et al, 2013).…”