Distemper Disease Research Articles

Evaluation of the Safety and Immunogenicity of a Multiple Epitope Polypeptide from Canine Distemper Virus (CDV) in Mice.

Morbillivirus canis is the etiological agent of a highly contagious disease that affects diverse domestic and wild animals. Vaccination is considered the most suitable strategy for controlling CDV dissemination, transmission, and distemper disease. However, the emergence of new CDV strains has led to the need to update the current vaccine strategies employed to prevent CDV infection in domestic and wild animals. Currently, there is a lack of effective alternatives for wild animals. Diverse computational tools, especially peptide-based therapies, enable the development of new universal vaccines. The aim of this study was to evaluate the safety and humoral and cellular immune response of a new generation of vaccines based on CDV peptides as single-peptide mixtures or multiepitope CDV polypeptides in mice. Twenty-four BALB/c mice were subjected to a three-dose regimen for 28 days. Seroconversion was evaluated via ELISA, and cellular immune responses were evaluated via flow cytometry through activation-induced markers (AIMs). Compared with the placebo, the peptide mixture and multiepitope CDV polypeptide were safe, and seroconversion was statistically significant in the multiepitope CDV polypeptide and commercial vaccine (CV) groups. The numbers of antigen-specific CD4+CD134+ and IFN-γ+ T cells, CD8+ T cells and TNF-α- and IL-6-producing cells were greater in the mice immunized with the multiepitope CDV polypeptide than in the control mice. This combined approach represents a potential step forward in developing new immunization candidates or enhancing current commercial vaccines to control CDV disease in domestic dogs and wild animals.

Dynamics of the postvaccinal humoral immune response in canids vaccinated against CDV

Canine distemper disease, a viral disease that affects canids, domestic and wild, regardless of age, race and sex, is one of the frequent infectious diseases in this species, evolving seriously, with a fatal outcome. Vaccination schemes practiced in companion canids also include vaccination against this infection produced by the canine distemper virus (CDV). This study aims to monitor the titer of anti-CDV antibodies after vaccination, in order to evaluate the efficiency of post-vaccination immune response.

Phenotypic Characterization of Encephalitis in the BRAINS of Badgers Naturally Infected with Canine Distemper Virus

Canine distemper virus (CDV) affects a huge diversity of domestic and wild carnivores, with increasing numbers of mortality events worldwide. The local cell-mediated immune response elicited against a natural infection is an important factor in determining the outcome of CDV infection. Therefore, the purposes of this study were to describe the local immune response within the central nervous systems (CNSs) of seven badgers naturally infected with CDV in Asturias (Atlantic Spain) and to determine the phenotype and distribution of microglial cells, T and B lymphocytes, and astrocytes in the foci of gliosis located in the thalamus and cerebellum using immunohistochemistry. The immunohistochemical assessment demonstrated the presence of Iba1-positive microglia and GFAP-positive astrocytes in the foci of gliosis, whereas T (CD3-negative) or B (CD20-negative) lymphocytes in those same lesions were absent. Our results also revealed that the badgers with natural CDV encephalitis presented lesions mostly located in the white matter of the thalamus and cerebellum, suggesting a CDV-specific tropism for the white matter of badger brains in those locations. The knowledge gained in the field of the immunopathogenesis of distemper disease affecting the CNSs of badgers could help to clarify CDV disease patterns in this species.

SEROLOGIC RESPONSE AND ADVERSE EFFECTS OF RECOMBINANT CANINE DISTEMPER VACCINATION IN THREE AQUARIUM-HOUSED WALRUSES (ODOBENUS ROSMARUS).

Fatalities have been associated with phocine and canine distemper viruses in marine mammals, including pinnipeds. No data are available regarding distemper disease or vaccination in walruses. This study evaluates seroconversion and clinical adverse effects following administration of a canarypox-vectored recombinant distemper vaccination (two 1-ml doses, 3 wk apart) in three adult aquarium-housed walruses. Serum antibodies to distemper were measured using seroneutralization on blood samples collected under operant conditioning prior to and for 12 mon after vaccination or until titers were <32. All walruses seroconverted. Medium positive titers (64-128) were detected for 4 to 9.5 mon in two of three individuals. Interindividual variability was noted, with one individual displaying only low positive titers. Major swelling at the site of injection and lameness for a week following injection occurred in all three walruses. Further studies on dosing amount and interval are needed to make vaccine recommendations in this species.

LRP6 Is a Functional Receptor for Attenuated Canine Distemper Virus.

Wild-type canine distemper virus (CDV) is an important pathogen of dogs as well as wildlife that can infect immune and epithelial cells through two known receptors: the signaling lymphocytic activation molecule (SLAM) and nectin-4, respectively. Conversely, the ferret and egg-adapted CDV-Onderstepoort strain (CDV-OP) is employed as an effective vaccine for dogs. CDV-OP also exhibits promising oncolytic properties, such as its abilities to infect and kill multiple cancer cells in vitro. Interestingly, several cancer cells do not express SLAM or nectin-4, suggesting the presence of a yet unknown entry factor for CDV-OP. By conducting a genome-wide CRISPR/Cas9 knockout (KO) screen in CDV-OP-susceptible canine mammary carcinoma P114 cells, which neither express SLAM nor nectin-4, we identified low-density lipoprotein receptor-related protein 6 (LRP6) as a host factor that promotes CDV-OP infectivity. Whereas the genetic ablation of LRP6 rendered cells resistant to infection, ectopic expression in resistant LRP6KO cells restored susceptibility. Furthermore, multiple functional studies revealed that (i) the overexpression of LRP6 leads to increased cell-cell fusion, (ii) a soluble construct of the viral receptor-binding protein (solHOP) interacts with a soluble form of LRP6 (solLRP6), (iii) an H-OP point mutant that prevents interaction with solLRP6 abrogates cell entry in multiple cell lines once transferred into recombinant viral particles, and (iv) vesicular stomatitis virus (VSV) pseudotyped with CDV-OP envelope glycoproteins loses its infectivity in LRP6KO cells. Collectively, our study identified LRP6 as the long sought-after cell entry receptor of CDV-OP in multiple cell lines, which set the molecular bases to refine our understanding of viral-cell adaptation and to further investigate its oncolytic properties. IMPORTANCE Oncolytic viruses (OV) have gathered increasing interest in recent years as an alternative option to treat cancers. The Onderstepoort strain of canine distemper virus (CDV-OP), an enveloped RNA virus belonging to the genus Morbillivirus, is employed as a safe and efficient vaccine for dogs against distemper disease. Importantly, although CDV-OP can infect and kill multiple cancer cell lines, the basic mechanisms of entry remain to be elucidated, as most of those transformed cells do not express natural receptors (i.e., SLAM and nectin-4). In this study, using a genome-wide CRISPR/Cas9 knockout screen, we describe the discovery of LRP6 as a novel functional entry receptor for CDV-OP in various cancer cell lines and thereby uncover a basic mechanism of cell culture adaptation. Since LRP6 is upregulated in various cancer types, our data provide important insights in order to further investigate the oncolytic properties of CDV-OP.

First report of canine morbillivirus infection of adipose tissue-derived stem cells from dogs with distemper.

Background and Aim:Ribonucleic acid viruses remain latent in different cell types, including mesenchymal stem cells; however, the distemper virus remains undetected in these cells. This study aimed to determine whether adipose stem cells (ASCs) from dogs with distemper disease are infected with the canine morbillivirus (CM).Materials and Methods:Twelve dogs with the neurological phase of the disease and who were positive for CM by reverse transcription polymerase chain reaction (RT-PCR), were studied. ASCs from adipose tissue of the lesser omentum of these infected dogs were isolated and characterized. Direct fluorescence was used to detect the viral antigen in cell cultures. Flow cytometry and RT-PCR identified detectable quantities of the virus in two cultures, while electron microscopy confirmed the CM particles within ASCs.Results:This study revealed that ASCs of the omentum of dogs with distemper disease can be infected with CM, indicating their possible involvement in this virus latency and persistence. This suggests that its detection should be considered within the quality control process of stem cells intended for regenerative medicine.Conclusion:To the best of our knowledge, this is the first study that demonstrates that omentum ASCs from dogs with distemper disease can be infected with CM and may be involved in viral latency or persistence. Our study also suggests that the detection of CM should be considered within the quality control process of stem cells intended for regenerative medicine.

Investigation and control strategy for canine distemper disease on endangered wild dog species: a model-based approach

The canine distemper virus (CDV) is a major threat to the already endangered wild dogs. We propose an evidence-based mathematical model of canine distemper in the wild to predict the rate and possibility of disease spread in wild dogs under a different scenario. We find the endemic and disease-free equilibrium points and the condition for their stability from the model. The bifurcation analysis of the model shows how the endemic equilibrium can be transformed into the disease-free equilibrium through parameters that represent fundamental ecological properties. The sensitivity of these parameters to the secondary disease spread points out the specific interaction rates and a birth rate that should be targeted to reduce the CDV outbreak. We suggest target parameters for controlling the disease outbreak considering the plausibility of manipulating them in terms of implications besides the sensitivity of the parameters. Finally, this article proposes two specific control strategies based on this modeling framework: isolation and birth-control-reintroduction. Since the isolation strategy may be cost-intensive, we modify our model to quantify the isolation rate necessary to reduce the disease outbreak. We suggest that the birth-control-reintroduction strategy based on the proposed model is cost-effective for a small contaminated area. Overall, the models in this study is applied in the field of conservation biology.

Canine Distemper Virus (CDV) – The COVID-19 of the Wild Cats

In the year 1994, the Serengeti lion population was decimated by a canine distemper disease outbreak. Retrospective investigations showed that this host population had already been in contact with the pathogen in 1981 without any detected sign of disease. As an alternative to the virus mutation hypothesis to explain this difference in virulences observed in 1981 and 1994, we propose a novel mechanism of disease emergence based on variation in population immunity. We use a stochastic model to show that stochastic fluctuations in pathogen circulation, owing to a low probability of virus transmission from its reservoir to the target host and thereby resulting in variations in the global immunity level of the target host population, can explain the observations made in Serengeti. This mechanism may also be involved in other infectious disease emergences or re-emergences.

Antigenic and immunogenic properties of the canine distemper virus nucleocapsid protein expressed in Escherichia coli employing codon optimized synthetic gene

ABSTRACT: Despite common occurrence and importance of canine distemper disease the majority of tests currently available for diagnosis are hampered by either low sensitivity or specificity. In this study it was evaluated antigenic and immunogenic characteristics of a conserved region of nucleocapsid protein of canine distemper virus (rCDV NP) expressed in Escherichia coli employing a codon optimized synthetic gene. The expression of rCDVNP in Star strain (mean 300μg/mL, purified) was confirmed by SDS-PAGE and Western blot analysis by using His-Tag monoclonal antibodies. Western blot and ELISA, employing positive and negative control dog sera, demonstrated the rCDVNP antigenicity. The rCDVNP was inoculated in hens and immunoglobulin Y (IgY) was purified from the egg yolk. The mean yield of IgY was 28.55mg/mL. IgY reacted with the recombinant protein as demonstrated by Western blot and ELISA assays. In summary, our findings demonstrated that rCDVNP is antigenic since CDV positive dog sera recognized the protein in vitro. Additionally, the rCDVNP proved to be immunogenic in hens being possible to isolate a high concentration of specific IgY antibodies from the egg yolk. Taken together, these results indicate that the rCDVNP along with the specific IgY could be useful tools for development of the canine distemper immunodiagnostic assays.

Erratum.

Aust Vet J 2016;94:215–222. doi: 10.1111/avj.12457 Epidemiology and clinical presentation of canine distemper disease in dogs and ferrets in Australia, 2006–2014 SE Wyllie, M Kelman and MP Ward The Publisher would like to draw the reader's attention to the error in the following article: The corresponding author's email address should be Michael.ward@sydney.edu.au instead of Michael.ward@sydney.edu. The Publisher apologises for this error and any confusion it may have caused.

Epidemiology and clinical presentation of canine distemper disease in dogs and ferrets in Australia, 2006-2014.

To determine the status and distribution of distemper in Australian dogs and ferrets. Retrospective case series. Cases were identified via a national voluntary disease reporting system, veterinarian groups and a national laboratory database. The geographic distribution, seasonal distribution, signalment and clinical presentation of cases were described using maps and frequency distributions. A total of 48 individually affected dogs and ferrets in 27 case groups were identified, including eight confirmed case groups (> one individual). Confirmed cases were more common in summer and on the central coast of New South Wales and southern Victoria, and occurred exclusively in young, unvaccinated dogs. For dogs there was no obvious sex predilection. A mortality rate of 100% in ferrets and up to 77% in dogs was estimated. Neurological, gastrointestinal and respiratory were the most commonly reported systems affected in dogs and ferrets. There was no evidence that any large, unreported outbreaks occurred during the study period. Continuation of vaccination against canine distemper virus is justified within Australia, particularly for younger dogs. Veterinarians should continue to consider distemper in their differential diagnosis of cases with neurological, gastrointestinal and respiratory presentation.

Controversial results of therapy with mesenchymal stem cells in the acute phase of canine distemper disease.

Distemper disease is an infectious disease reported in several species of domestic and wild carnivores. The high mortality rate of animals infected with canine distemper virus (CDV) treated with currently available therapies has driven the study of new efficacious treatments. Mesenchymal stem cell (MSC)-based therapy is a promising therapeutic option for many degenerative, hereditary, and inflammatory diseases. Therefore, the aim of this study was to characterize stem cells derived from the canine fetal olfactory epithelium and to assess the systemic response of animals infected with CDV to symptomatic therapy and treatment with MSCs. Eight domestic mongrel dogs (N = 8) were divided into two groups: support group (SG) (N = 5) and support group + cell therapy (SGCT) (N = 3), which were monitored over 15 days. Blood samples were collected on days 0, 6, 9, 12, and 15 to assess blood count and serum biochemistry (urea, creatinine, alanine transferase, alkaline phosphatase, gamma-glutamyl transferase, total protein, albumin, and globulin), and urine samples were obtained on days 0 and 15 for urinary evaluation (urine I). The results showed a high mortality rate (SG = 4 and SGCT = 2), providing inadequate data on the clinical course of CDV infection. MSC therapy resulted in no significant improvement when administered during the acute phase of canine distemper disease, and a prevalence of animals with high mortality rate was found in both groups due to the severity of symptoms.

The evaluation of retrospective pathological lesions on spirocercosis (Spirocerca lupi) in dogs.

From 1998 to 2012, 42 dogs with spirocercosis referred to pathology Department of Veterinary Faculty, Tehran University. Frequency of spirocercosis was higher in October, November, December, January, February, March months. Averagely, the cases were 4.73years old of age, so that 59.3% of them were male. The major pathological findings were located in distal part of esophagus (57%, n=24), stomach (24%, n=10), and aorta (9.5%, n=4), respectively. In addition, 7% (n=3) were in esophagus and stomach, 2% (n=1) in esophagus and aorta, 42% (n=18) indicated pulmonary lesions with hyperemia, atelectasis, edema and pneumonia. In 35% (n=15) of cases were with hepatic lesions hyperemia and fatty change. However, 26% (n=11) cases demonstrated renal lesions with hyperemia, interstitial nephritis, and 24% (n=10) encompassed urinary bladder lesions with hyperemia and adhesive cystitis. Furthermore, sudden death occurred in 7% (n=3) as well as cachexia in 7% (n=3) cases. Some spirocercosis cases (12%, n=5) were accompanied by distemper disease, mixed mammary gland tumor (2%, n=1) and parasitic dermatitis due to demodicosis (9.5%, n=4). Presumably some of pathological findings were related or emerged by other sort of diseases such as distemper.

Clostridium perfringens type A related enteritis: A case report in dogs

درتاریخ11/3/ 1389در یک کانون پرورش سگ در استان تهران که 82 قلاده سگ در آن نگهداری می گردید، 7 مورد بیمار شده و 5 مورد تلف گردیدند. علائم بالینی بیماری عبارت بودند از اسهال، اسهال خونی، تب، افسردگی، علائم عصبی و مرگ ناگهانی. یافته‌های کالبد گشایی عبارت بودند از انتریت هموراژیک، گاستریت موکوسی، وجود کانون های نکروز گرد در حدود cm 0/5 در کورتکس مغز به همراه پرخونی و خونریزی.‌ 4 قلاده سگ مورد کالبد گشایی قرار گرفتند. محتویات روده مورد آزمایشات باکتری شناسی قرار گرفت و در نهایت پس از مشخص شدن کلستریدیوم پرفرنژنس‌ ‌به منظور تعیین تیپ آزمایش PCR انجام شد و باکتری کلستریدیوم پرفرنژنس تیپ A مشخص گردید. در 4 قلاده سگ با توجه به ضایعات انتریت هموراژیک، آزمایش سریع آنتی بادی برای بررسی بیماری های ناشی از پارواویروس و دیستمپر انجام گردید که 2 مورد از توله سگ ها از نظربیماری دیستمپر مثبت اعلام گردیدند. با توجه به وجود انسفالیت غیر چرکی، گلیوز همراه با گنجیدگی داخل هسته ای در آستروسیت ها، PVC و پنومونی بینابینی نتیجه گیری گردید که احتمالا ابتدا بیماری دیستمپر عمل کرده، ضایعات اولیه و مهم را به وجود آورده و آنگاه به طور ثانویه ضایعات انتریت هموراژیک و اسهال در اثر باکتری کلستریدیوم پرفرنژنس تیپ A ایجاد شده است.

Immunopathogenic and Neurological Mechanisms of Canine Distemper Virus

Canine distemper is a highly contagious viral disease caused by the canine distemper virus (CDV), which is a member of the Morbillivirus genus, Paramyxoviridae family. Animals that most commonly suffer from this disease belong to the Canidae family; however, the spectrum of natural hosts for CDV also includes several other families of the order Carnivora. The infectious disease presents worldwide distribution and maintains a high incidence and high levels of lethality, despite the availability of effective vaccines, and no specific treatment. CDV infection in dogs is characterized by the presentation of systemic and/or neurological courses, and viral persistence in some organs, including the central nervous system (CNS) and lymphoid tissues. An elucidation of the pathogenic mechanisms involved in canine distemper disease will lead to a better understanding of the injuries and clinical manifestations caused by CDV. Ultimately, further insight about this disease will enable the improvement of diagnostic methods as well as therapeutic studies.

From the Clinical to the Molecular Diagnosis of Canine Distemper Disease

Canine distemper virus (CDV) is a member of genus Morbillivirus and family Paramyxoviridae that have a negative single-strand RNA genome (Appel, M.J.G., 1987). Canine distemper is a multi-systemic viral disease of dogs characterized by a wide variety of clinical manifestations and lesions, and several other protozoal, bacterial and viral infections as well as toxin poisoning mimic distemper symptoms (Beineke et al, 2009; Green & Appel, 1998). Therefore, the signs are not always suggestive for canine distemper suspicion, and the etiological diagnosis need to be performed. The most used methods of CDV diagnosis are ELISA, direct and indirect immunofluorescent antibody tests, seroneutralisation, and immunofluorescent techniques to detect viral antigen were commercially available, and the veterinary laboratories usually perform them (Green & Appel, 1998). Unfortunately, the most of these techniques have their diagnostic limitation and sometimes can lead to false positive results. Thirty cases of dogs, different mixed breeds and aged less than one year were investigated for CDV infection by ELISA IgG (ImmunoComb®, Biogal, Israel), ELISA IgM (ImmunoComb®, Biogal, Israel), Immunochromatographic CDV-Ag test (CDV IC, Agrolabo, Italy), and reverse transcription polymerase chain reaction (RT-PCR). The blood serum samples were collected from unvaccinated dogs with nervous manifestations and a history of disease up to one month. Eight (8/30) samples were IgM and IgG positive, fourteen (14/30) samples were only IgG positive, all immunochromatographic antigenic tests and RT-PCR were negative. In our opinion, the presence of CDV-antibodies leads to false-negative results for the antigenic and genomic viral tests. These results suggest that blood serum samples from dogs with nervous manifestations are not useful for antigenic tests and RT-PCR.

Genetic diversity and phylogenetic analysis of the attachment glycoprotein of phocine distemper viruses of the 2002 and 1988 epizootics

To investigate the possible origin and spread of the dramatic re-emergent 2002 distemper epizootic observed among seals in Danish Waters, we have sequenced wild-type genes of the attachment (H) glycoproteins of viruses from both the 2002 and 1988 epizootics. Phylogenetic analysis of the H genes of phocine distemper virus (PDV) together with other morbilliviruses, suggests that the re-emergent 2002 PDV is more closely related to a putative recent ancestral PDV than the 1988 PDV isolates. Moreover, upsurges of distemper disease in land-living carnivores linked in time and locality to the 2002 seal epizootic in Danish Waters was investigated and determined to be caused by canine distemper virus, the closest relative of PDV, revealing no direct epidemiological link to the seal epizootics.

The canine distemper epidemic in Serengeti: are lions victims of a new highly virulent canine distemper virus strain, or is pathogen circulation stochasticity to blame?

In the year 1994, the Serengeti lion population was decimated by a canine distemper disease outbreak. Retrospective investigations showed that this host population had already been in contact with the pathogen in 1981 without any detected sign of disease. As an alternative to the virus mutation hypothesis to explain this difference in virulences observed in 1981 and 1994, we propose a novel mechanism of disease emergence based on variation in population immunity. We use a stochastic model to show that stochastic fluctuations in pathogen circulation, owing to a low probability of virus transmission from its reservoir to the target host and thereby resulting in variations in the global immunity level of the target host population, can explain the observations made in Serengeti. This mechanism may also be involved in other infectious disease emergences or re-emergences.

Avaliação da urina e de leucócitos como amostras biológicas para a detecção ante mortem do vírus da cinomose canina por RT-PCR em cães naturalmente infectados

Urine and leucocytes were comparatively evaluated as clinical samples for ante mortem detection of the canine distemper virus (CDV) by a reverse transcription-polymerase chain reaction (RT-PCR) assay. One hundred and eighty eight dogs with clinical symptoms of distemper, were distributed in three groups. The group A was constituted of 93 dogs with systemic signs of distemper; the group B by 11 dogs with neurological signs, and the group C by 84 dogs that presented simultaneously systemic and neurological signs. In 66.5% (125/188) of the dogs was amplified an amplicon with 287 base pair of the CDV nucleoprotein gene. In 60.8% (76/125) of the animals the CDV was detected simultaneously in the urine and leucocytes, and in 39.2% (49/125) of the dogs just a type of clinical sample (urine: n=37; leucocytes: n=12) was positive. These results demonstrate that the different forms of clinical distemper disease can hinder the choice of only one type of clinical sample to carry out the ante mortem etiological diagnosis of CDV infection, and false-negative results can be generated.