Coinfection of Canine Distemper Virus and Rabies Virus in Wildlife Samples Submitted for Routine Rabies Testing.

Canine distemper virus (also known as Canine morbillivirus), the etiologic agent of canine distemper, is a highly contagious pathogen causing a multisystemic infection in carnivores globally. Canine distemper may be clinically indistinguishable from rabies, and outbreaks of either disease are major concerns. In the US, both diseases are endemic and managed by parenteral vaccination in domestic animals. In wildlife, oral vaccination and trap-vaccinate-release programs are available for rabies prevention, but no such strategies exist for canine distemper. We evaluated the prevalence at which canine distemper virus occurred concurrently in animals infected with rabies virus. Real-time quantitative reverse transcriptase PCR (qRT-PCR) was performed on specimens previously diagnosed with rabies during 2017-19 by the New York State Rabies Laboratory. Real-time qRT-PCR detected concurrent canine distemper virus infection in 73 of 1,302 animals with rabies virus. Coinfection rates were approximately 9% in Procyon lotor, 2% in Vulpes vulpes, and 0.4% in Mephitis mephitis, with an overall prevalence of 5.6%. As comorbidities in wildlife occur, laboratory-based surveillance and confirmatory testing are critical to rapid decision making for disease prevention. Rabies virus incursions are expensive and difficult to manage, and spillover events create health risks to humans and domestic animals as well as to free-roaming wildlife.

Radiographic evidence of metaphyseal sclerosis secondary to canine distemper virus: 4 cases in juvenile dogs.

BACKGROUND: Metaphyseal sclerosis secondary to canine distemper virus has been described histopathologically, but its radiographic appearance has not been described. OBJECTIVES: Describe the radiographic appearance of metaphyseal sclerosis secondary to canine distemper virus in juvenile dogs as distinct from metaphyseal osteopathy (formerly called hypertrophic osteodystrophy). ANIMALS: Four dogs (2 intact females and 2 intact males) between 2.5 and 4 months of age presented to 2 different veterinary teaching hospitals. METHODS: Retrospective case series in which definitive diagnosis of canine distemper virus based on antemortem positive reverse transcription-polymerase chain reaction (RT-PCR) result or necropsy was required. RESULTS: All 4 dogs were presented for evaluation of neurologic abnormalities, respiratory signs, and lethargy; 2 dogs had gastrointestinal signs and ocular abnormalities. Radiographs on all patients featured multifocal, symmetric, metaphyseal sclerosis, with no evidence of lysis or changes to the adjacent growth plate. The metaphyseal sclerosis was most apparent at the proximal humeral diaphyses and other included long bones. Diagnosis of distemper was confirmed by necropsy (2 of 4 dogs) or positive RT-PCR results (2 of 4 dogs). Three dogs were euthanized because of progressive illness, and 1 dog was lost to follow-up. CONCLUSION AND CLINICAL IMPORTANCE: Identification of metaphyseal sclerosis on radiographs during diagnostic evaluation of young dogs should lead to a clinical suspicion of canine distemper virus infection. Sclerosis identified secondary to canine distemper virus is distinct from the necrosis and inflammation of metaphyseal osteopathy.

Evaluation of Intrathecal Injection of Modified Live Newcastle Disease Virus Vaccine in Dogs with Canine Distemper Encephalitis.

The neurological form of canine distemper virus (CDV) infection can occur concurrently with systemic signs or develop following apparent recovery. There are no specific antiviral or immunomodulatory therapies recognized for treatment of CDV infections, and the neurological form typically carries with it a high mortality rate. The intrathecal injection of a modified live Newcastle disease virus vaccine (NDV-MLV) has been proposed for the treatment of the neurological forms of CDV infections. Thirteen dogs confirmed to have canine distemper infections by polymerase chain reaction testing and with neurological signs consistent with CDV infection were treated with an intrathecal injection of NDV-MLV and were scheduled for re-evaluation 3-4 mo later. Six dogs survived to follow-up and four dogs survived long term (>3 yr). Cerebrospinal fluid cytokines were measured and reported. Changes in cerebrospinal fluid cytokines and long-term survival could not be attributed to the intrathecal injection of NDV-MLV, and this therapy cannot be recommended for treatment of dogs with neurological forms of CDV infection.

Eosinophilic meningoencephalitis caused by rat lungworm (Angiostrongylus cantonensis) migration in a white-eared opossum (Didelphis albiventris) with concurrent distemper virus in southern Brazil.

Angiostrongylus cantonensis is a worldwide zoonotic parasite that causes eosinophilic meningoencephalitis in many species of animals including humans. This report describes neuro-angiostrongylosis in a white-eared opossum that showed nervous clinical signs such as circling and depression. At necropsy, no relevant macroscopic lesions were observed. Histologically, eosinophilic meningoencephalitis was associated with multiple sections of nematodes and many intracytoplasmic eosinophilic inclusion bodies within gastric parietal cells. Immunohistochemistry was strongly positive for canine distemper virus in the stomach but there was no immunolabeling in the brain. This study describes a fatal case of eosinophilic meningoencephalitis by A. cantonensis with canine distemper virus concurrent infection in a white-eared opossum in southern Brazil, with histological characterization and molecular confirmation of the parasitism.

Histopathological Features of Spinal Cord Lesions in Dogs with Distemper-Associated Demyelinating Leucoencephalomyelitis.

Demyelinating leucoencephalomyelitis (DLEM) is one of the pathological presentations of canine distemper, but its histological characteristics and topographical distribution of spinal cord injuries have been poorly explored. Seventeen dogs submitted for necropsy to a veterinary pathology service (2006-2008) and diagnosed with distemper-associated DLEM were investigated. Seventy-two of 231 spinal cord sections from these animals had histological lesions, which consistently affected the white matter. The lumbosacral region was mostly affected (13/17), followed by the thoracolumbar (11/17), cervical (9/17) and cervicothoracic (9/17) regions. Among the 72 affected cord sections, lesions in the lateral (42/72) and dorsal funiculi (31/72) were the most common. Demyelination (17/17), astrocytosis (17/17), microgliosis (17/17), gemistocytes (11/17) and non-suppurative inflammation (10/17) were frequently seen in the white matter. Grey matter changes were less common, and included gliosis (8/17), non-suppurative inflammation (7/17) and malacia (5/17). Acute lesions were most prevalent (13/17) but it was common (10/17) for the same dog to have lesions at different stages of evolution in distinct spinal cord regions. Pathological changes in several spinal cords did not correlate with the reported clinical signs and some dogs did not present with spinal cord-related clinical signs. Our results highlight important aspects of the distribution and morphology of spinal cord lesions in dogs with distemper-associated DLEM, and may assist clinicians and pathologists in the diagnosis of spontaneous cases of this important infectious disease and contribute to further studies concerning distemper pathogenesis.

Myocarditis caused by naturally acquired canine distemper virus infection in 4 dogs.

Canine distemper virus (CDV) has long been recognized as a cause of myocarditis; however, cases of myocarditis caused by naturally acquired CDV infection have been reported only rarely in dogs. We describe here our retrospective study of naturally acquired systemic CDV infection in 4 dogs, 4-7 wk old, that had myocarditis, with myocardial necrosis and fibrosis. One of the 4 dogs had intracytoplasmic eosinophilic inclusion bodies in cardiomyocytes. Other lesions included bronchointerstitial pneumonia (4 of 4), necrotizing hepatitis (2 of 4), splenic lymphoid necrosis (2 of 4), encephalitis (1 of 3; brain was not submitted in 1 case), and necrotizing gastroenteritis (1 of 4). The presence of CDV in the heart was confirmed by immunohistochemistry in all 4 dogs.

Mesenchymal to epithelial transition driven by canine distemper virus infection of canine histiocytic sarcoma cells contributes to a reduced cell motility in vitro.

Sarcomas especially of histiocytic origin often possess a poor prognosis and response to conventional therapies. Interestingly, tumours undergoing mesenchymal to epithelial transition (MET) are often associated with a favourable clinical outcome. This process is characterized by an increased expression of epithelial markers leading to a decreased invasion and metastatic rate. Based on the failure of conventional therapies, viral oncolysis might represent a promising alternative with canine distemper virus (CDV) as a possible candidate. This study hypothesizes that a CDV infection of canine histiocytic sarcoma cells (DH82 cells) triggers the MET process leading to a decreased cellular motility. Immunofluorescence and immunoblotting were used to investigate the expression of epithelial and mesenchymal markers followed by scratch assay and an invasion assay as functional confirmation. Furthermore, microarray data were analysed for genes associated with the MET process, invasion and angiogenesis. CDV-infected cells exhibited an increased expression of epithelial markers such as E-cadherin and cytokeratin 8 compared to controls, indicating a MET process. This was accompanied by a reduced cell motility and invasiveness. Summarized, these results suggest that CDV infection of DH82 cells triggers the MET process by an increased expression of epithelial markers resulting in a decreased cell motility in vitro.

Distemper Encephalomyelitis Presenting with Lower Motor Neuron Signs in a Young Dog.

A 4 mo old spayed female mixed-breed dog was presented for focal lower motor neuron signs of the right forelimb and marked hyperesthesia on axillary palpation. Her signs progressed rapidly over the following days to diffuse lower motor neuron signs in all limbs and a seizure. MRI demonstrated a focal, slightly right-sided, 2.5 cm region of noncontrast-enhancing T2 hyperintensity and T1 isointensity at C4-C5 spinal cord segments. Imaging of the brain was unremarkable. The dog was euthanized as a result of poor prognosis. Polymerase chain reaction on cerebrospinal fluid and immunohistochemistry of brain tissue were both positive for canine distemper virus. This report documents an atypical presentation of canine distemper encephalomyelitis causing lower motor neuron signs and hyperesthesia.

Pyogranulomatous pleuropneumonia caused by Nocardia asiatica in a dog coinfected with canine morbillivirus (canine distemper virus).

Nocardia asiatica causing pyogranulomatous pleuropneumonia is reported for the first time in a dog coinfected with canine morbillivirus (CM), diagnosed based on epidemiological, clinical, haematological, images, microbiological, histopathological, polymerase chain reaction and hsp65 gene sequencing findings. The immunosuppression of CM probably favoured the opportunistic behaviour of N. asiatica. Despite the therapeutic measures, the animal died, mainly due to respiratory distress. The association of methods to improve early diagnosis, therapy procedures and prognosis of canine nocardiosis is discussed, as well as the close relationship between pets and their owners, which may favour the transmission of pathogens such as Nocardia from pets-to-humans, which poses an emerging public health issue.

Rhodococcus equi pVAPN type causing pneumonia in a dog coinfected with canine morbillivirus (distemper virus) and Toxoplasma gondii.

Canine morbillivirus (previously, canine distemper virus, CDV) is a highly contagious infectious disease-causing agent that produces immunosuppressive infections and multiple clinical signs. Canine toxoplasmosis is an opportunistic disease characterized by enteric, pulmonary, and neuromuscular signs that might be confused with CDV-induced infections. Rhodococcus equi is a Gram-positive intracellular facultative bacterium that is also opportunistic in nature, and causes pyogranulomatous infections in humans and multiple host animals, although canine rhodococcosis is rare or unrecognized. The pathogenicity of R. equi is intimately related to the presence of plasmid-encoded virulence-associated proteins (Vap). Three host-adapted virulence plasmid types of R. equi have been recognized: the circular pVAPA and pVAPB are associated with equine and porcine strains, respectively, and the recently detected linear pVAPN virulence plasmid is related to bovine isolates. Nevertheless, data regarding the detection of host-adapted virulence plasmid types of R. equi isolated from companion animals are scarce. This report describes a case of an uncommon coinfection due to R. equi, T. gondii and CDV, which was diagnosed in a pet dog with respiratory distress. In this case, CDV most likely induced immunosuppression, which facilitated opportunistic infections by R. equi and T. gondii. The analysis of the virulence profile of R. equi revealed the novel pVAPN plasmid type, initially related to bovine strains. This is the second report of the bovine-associated pVAPN type in a pet dog, with an unusual coinfection with T. gondii and CDV. These findings represent a public health concern due to the close contact between pet animals and their owners, particularly because the pVAPN plasmid type was recently detected in people with HIV/AIDS from the same geographical region.

Frequency of Virus Coinfection in Raccoons ( Procyon lotor) and Striped Skunks ( Mephitis mephitis) During a Concurrent Rabies and Canine Distemper Outbreak.

Rabies and canine distemper virus infections in wildlife share similar presenting signs. Canine distemper virus was detected using real-time PCR of conjunctival swabs in rabies positive raccoons (22/32) and skunks (7/34) during a concurrent rabies and canine distemper outbreak in Ontario, Canada in 2015-16. Coinfections with both viruses should be considered, particularly in distemper endemic areas that are at risk of rabies incursion.

Pneumonia due to Talaromyces marneffei in a Dog from Southern Brazil with Concomitant Canine Distemper Virus Infection.

The pathological and molecular findings associated with Talaromyces marneffei-induced pneumonia with concomitant infection by canine distemper virus (CDV) are described in a dog. The principal pathological alteration occurred in the lungs. Histopathology confirmed multifocal granulomatous pneumonia associated with numerous intralesional and intracellular septate fission cells consistent with T. marneffei. A molecular assay designed to amplify a partial fragment of the 18S rRNA gene of T. marneffei provided positive results from two fungal cultures derived from the lung. Sequencing and phylogenetic analyses confirmed the results of polymerase chain reaction (PCR). Furthermore, antigens of the CDV N protein were identified within the bronchial epithelium by immunohistochemistry and a PCR assay amplified the CDV N gene from hepatic and pulmonary fragments. Collectively, the pathological and molecular techniques confirmed a diagnosis of T. marneffei-induced pneumonia with concomitant infection by CDV. These findings represent the first description of pulmonary penicilliosis in the dog and extend the geographical niche of this emerging infectious pathogen. In this case, infection by CDV may have induced immunosuppression, which facilitated the development of pulmonary penicilliosis.

Effect of the probiotic Lactobacillus murinus LbP2 on clinical parameters of dogs with distemper-associated diarrhea.

The objective of this study was to assess the effect of the probiotic Lactobacillus murinus native strain (LbP2) on general clinical parameters of dogs with distemper-associated diarrhea. Two groups of dogs over 60 d of age with distemper and diarrhea were used in the study, which was done at the Animal Hospital of the Veterinary Faculty of the University of Uruguay, Montevideo, Uruguay. The dogs were treated orally each day for 5 d with the probiotic or with a placebo (vehicle without bacteria). Clinical parameters were assessed and scored according to a system specially designed for this study. Blood parameters were also measured. Administration of the probiotic significantly improved the clinical score of the patients, whereas administration of the placebo did not. Stool output, fecal consistency, mental status, and appetite all improved in the probiotic-treated dogs. These results support previous findings of beneficial effects with the probiotic L. murinus LbP2 in dogs. Thus, combined with other therapeutic measures, probiotic treatment appears to be promising for the management of canine distemper-associated diarrhea.

L'objectif de la présente étude était d'évaluer l'effet d'une souche indigène du probiotique Lactobacillus murinus (LbP2) sur des paramètres cliniques généraux de chiens avec une diarrhée associée au distemper. Deux groupes de chiens âgés de plus de 60 jours avec du distemper et de la diarrhée ont fait partie de l'étude réalisée à l'hôpital de la Faculté vétérinaire de l'Université de l'Uruguay, Montevideo, Uruguay. Les chiens ont été traités quotidiennement par voie orale pendant 5 j avec le probiotique ou avec un placebo (véhicule sans les bactéries). Des paramètres cliniques ont été mesurés et notés selon un système conçu spécifiquement pour l'étude. Des paramètres sanguins ont également été mesurés. L'administration du probiotique améliorait significativement le pointage clinique des patients, alors que l'administration du placebo n'avait aucun effet. La production de selles, la consistance fécale, l'état mental, et l'appétit se sont tous améliorés chez les chiens traités avec le probiotique. Ces résultats confirment des résultats antérieurs d'effets bénéfiques du probiotique L. murinus LbP2 chez les chiens. Ainsi, combiner à d'autres mesures thérapeutiques, le traitement probiotique semble prometteur pour la gestion de diarrhée canine associée au distemper.(Traduit par Docteur Serge Messier).

Unusual Necrotizing Encephalitis in Raccoons and Skunks Concurrently Infected With Canine Distemper Virus and Sarcocystis sp.

Canine distemper virus commonly infects free-ranging, terrestrial mesopredators throughout the United States. Due to the immunosuppressive effects of the virus, concurrent opportunistic infections are also common. Among these, secondary systemic protozoal infections have been described in a number of species. We report an unusual presentation of necrotizing encephalitis associated withSarcocystissp in four raccoons and one skunk concurrently infected with canine distemper virus. Lesions were characterized by variably sized necrotizing cavitations composed of abundant mineral admixed with inflammatory cells and protozoa.Sarcocystissp was confirmed via immunohistochemistry using a monoclonal antibody toSarcocystis neurona The pathologic changes are similar to lesions in human AIDS patients infected withToxoplasma gondii.

Uncommon acute neurologic presentation of canine distemper in 4 adult dogs.

Four uncommon cases of canine distemper (CD) were diagnosed in vaccinated adult dogs. All dogs had acute onset of neurologic signs, including seizures, abnormal mentation, ataxia, and proprioceptive deficits. Polymerase chain reaction for CD virus was positive on cerebrospinal fluid in 2 cases. Due to rapid deterioration the dogs were euthanized and CD was confirmed by postmortem examination.

Rare présentation neurologique aiguë de la maladie de Carré chez 4 chiens adultes. Quatre cas peu communs de maladie de Carré chez des chiens adultes vaccinés. Tous les cas ont présenté un début aigu ou suraigu des signes neurologiques, comportant principalement des crises épileptiques, altération de l'état mental, ataxie, et déficits proprioceptifs. Dans deux cas, la PCR a été positive à la maladie de Carré dans le liquide céphalorachidien. En raison de la progression rapide des signes, les chiens ont été euthanasiés et la maladie de Carré confirmée par la nécropsie.(Traduit par Ana Roman).

Zymographic patterns of MMP-2 and MMP-9 in the CSF and cerebellum of dogs with subacute distemper leukoencephalitis.

Distemper leukoencephalitis is a disease caused by the canine distemper virus (CDV) infection. It is a demyelinating disease affecting mainly the white matter of the cerebellum and areas adjacent to the fourth ventricle; the enzymes of the matrix metalloproteinases (MMPs) group, especially MMP-2 and MMP-9 have a key role in the myelin basic protein fragmentation and in demyelination, as well as in leukocyte traffic into the nervous milieu. To evaluate the involvement of MMPs during subacute distemper leukoencephalitis, we measured the levels of MMP-2 and MMP-9 by zymography in the cerebrospinal fluid (CSF) and in the cerebellum of 14 dogs naturally infected with CDV and 10 uninfected dogs. The infected dogs presented high levels of pro-MMP-2 in the CSF and elevated levels of pro-MMP-2 and pro-MMP-9 in the cerebellar tissue. Active MMP-2 was detected in the CSF of some infected dogs. As active MMP-2 and MMP-9 are required for cellular migration across the blood-brain barrier and any interference between MMPs and their inhibitors may result in an amplification of demyelination, this study gives additional support to the involvement of MMPs during subacute distemper leukoencephalitis and suggests that MMP-2 and MMP-9 may take part in the brain inflammatory changes of this disease.

Fatal combined infection with canine distemper virus and orthopoxvirus in a group of Asian marmots (Marmota caudata).

A fatal combined infection with canine distemper virus (CDV) and orthopoxvirus (OPXV) in Asian marmots (Marmota caudata) is reported in this article. A total of 7 Asian marmots from a small zoological garden in Switzerland were found dead in hibernation during a routine check in the winter of 2011. The marmots died in February 2011. No clinical signs of disease were observed at any time. The viruses were detected in all individuals for which the tissues were available (n = 3). Detection of the viruses was performed by reverse transcription polymerase chain reaction. The most consistent gross lesion was a neck and thorax edema. A necrotizing pharyngitis and a multifocal necrotizing pneumonia were observed histologically. Numerous large intracytoplasmic eosinophilic inclusions were seen in the epithelial cells of the pharynx, of the airways, and in the skin keratinocytes. Brain lesions were limited to mild multifocal gliosis. Phylogenetic analysis revealed that the marmot CDV strain was closely related to the clusters of CDVs detected in Switzerland in wild carnivores during a local outbreak in 2002 and the 2009-2010 nationwide epidemic, suggesting a spillover of this virus from wildlife. The OPXV was most closely related to a strain of cowpoxvirus, a poxvirus species considered endemic in Europe. This is the first reported instance of CDV infection in a rodent species and of a combined CDV and OPXV infection.