Canine Distemper Virus Antigen Research Articles

Immunogenicity and protective efficacy of a novel bacterium-like particle-based vaccine displaying canine distemper virus antigens in mice and dogs.

Many sensitive species require a safe and effective distemper vaccine. Non-replicating vaccines are preferred. We constructed subunit particles displaying canine distemper virus (CDV) antigens based on a bacterium-like particle (BLP) delivery platform. The CDV-BLPs formulated with theMn jelly adjuvant induced robust humoral and cell-mediated immune responses to CDV in mice and dogs, thereby providing effective protection against a virulent virus challenge. This work is an important step in developing a CDV subunit vaccine.

Trace detection of canine distemper virus based on Michelson-interferometer sensing probe.

A single-mode-fiber (SMF)-multimode-fiber (MMF)-tri-core-fiber (TCF) Michelson probe structure is proposed for trace detection of canine distemper virus (CDV). One end of the TCF is cut flat and fused with the multimode fiber, and the other end is coated with a silver film to enhance the reflection, and an optic-fiber sensing probe with SMF-MMF-TCF structure is obtained. The (PDDA/PSS)3 multilayer film is modified on the surface of the fiber by layer-by-layer self-assembly method as a polyelectrolyte binder to immobilize CDV antibodies to form a (PDDA/PSS)3 /CDV antibody composite membrane for specific detection of CDV antigens. The response-recovery test of the sensor is performed to verify its repeatability. The detection limit, the sensitivity, and the linear fitting degree for CDV antigen are 0.1236 pg/mL, 1.1776 dB/(pg/mL), and 0.9899, respectively. At the same time, the stability, selectivity, and clinical samples of the sensors were also verified.

Trace detection of canine distemper virus based on surface-functionalized optic-fiber Mach–Zehnder interferometer and the Vernier effect

A surface-functionalized cascaded optic-fiber Mach–Zehnder interferometer (MZI) is proposed and fabricated for trace detection of canine distemper virus (CDV). The Vernier effect is formed based on single-mode fiber (SMF)-dislocation single-mode fiber-SMF. The two MZIs serve as the sensing arm and reference arm, respectively. The CDV antibody is modified on the sensing arm to detect CDV antigen, and the surface structure and morphology are analyzed by the atomic force microscope. The sensitivity of the cascaded MZI sensor is about 12 times than that of a single MZI. In the range of 0.1–104 pg ml−1 CDV, the detection limit of the cascaded MZI sensor is 0.1687 pg ml−1, and the response time is 25 min. The sensor also has good temperature, time stability and excellent selectivity. The biosensor has the advantages of low cost, easy preparation, high sensitivity and good selectivity, and has potential application for trace CDV detection.

Pathological and molecular investigation of canine distemper virus: Phylogenetic analysis of co-circulating genetic lineages in Türkiye.

Canine distemper virus (CDV) is a highly contagious virus that infects a wide variety of animals of carnivore species and may cause manifestations from subclinical infection to fatal disease. In this study, dogs clinically suspected having distemper were examined by reverse transcriptase-polymerase chain reaction (RT-PCR), histopathology and immuno-histochemistry. By histopathological examination, characteristic intracytoplasmic and/or intranuclear inclusion bodies were observed in the lung, stomach, small intestine, liver, kidney, spleen and central nervous system. Interstitial and broncho-interstitial pneumonia, gastroenteritis and encephalitis were revealed. CDV antigens were detected in all tissues with characteristic histopathological findings. The antigens were more abundant in the bronchial andbronchiolar epithelium and in the syntitial cells. Phylogenetic analyses were performed using the PCR-amplified partial sequences of the genes encoding the viral heamagglutinin and fusion proteins. The phylogenetic trees showed that the newly determined sequences were diverse and clustered within different lineages of the European or the Arctic strains.

A new method for obtaining the canine distemper virus antigen for RIHA.

A new method for obtaining the canine distemper virus antigen for RIHA.

Coinfection with canine distemper virus and canine circovirus in a dog in Brazil.

Canine distemper virus (CDV) and canine circovirus (CanineCV) have been described worldwide in multi-systemic disease in dogs. Both agents may be occasionally associated with other viral pathogens, but reports of coinfection by CDV and CanineCV associated with disease are rare. In this article, we report a coinfection between CDV and CanineCV detected during an investigation of viral agents involved in multisystemic disease in dogs in Southern Brazil. Molecular testing by PCR in lungs and intestines of 77 dogs necropsied in pathology services (2015-2020) revealed several single and mixed viral infections, including a CDV/CanineCV coinfection. In the case reported here, gross and histological findings were compatible with CDV pathology (bronchointerstitial pneumonia and viral intracytoplasmatic inclusions in pneumocytes and transitional epithelial cells of urinary bladder). CanineCV DNA and CDV antigens were detected in lung and intestine fragments by PCR and immunohistochemistry, respectively. CanineCV PCR amplicons subjected to nucleotide sequencing showed > 98.6% nucleotide identity with CanineCV sequences from GenBank. Although the role of CanineCV in the pathogenesis of the reported case could not be determined, our results show that CanineCV may be associated with other viral infections in cases of multisystemic disease in dogs. These results reinforce the circulation of CanineCV in dogs in Brazil and highlight the importance of including this virus in the list of differential diagnoses of respiratory and gastroenteric infectious diseases in dogs.

Detection of canine distemper virus in stray and pet dogs in Mosul city, Iraq

The current work was carried out during the period from September, 2020 to March, 2021 in Mosul city, Iraq, with the objectives to detection of canine distemper virus (CDV) for the first time in Mosul using microscopic examination of blood smears, rapid serum antigen test and sandwich ELISA test as well as determine the agreement between the different diagnostic methods. A total of 92 blood samples were collected from suspected dogs with CDV (69 stray dogs and 23 Pet dogs). A primarily detection of CDV in blood smear by the presence of inclusion bodies in erythrocytes and leukocytes, followed by detection of CDV antigen in serum using rapid test and sandwich ELISA test. Results indicate that the infection rates of CDV in dogs were 32.6%, 13%, and 19.5% using microscopic examination, rapid test and sandwich ELISA test respectively. A statistically significant higher infection rate was reported in stray dogs compared to pet dogs based on all diagnostic tests used in this study. Based on Kappa values 0.413, 0.675, 0.745, there were moderate agreement between microscopic examination and rapid test, and substantial agreement between microscopic examination and sandwich ELISA test, also between rapid test and sandwich ELISA test respectively. In conclusions, CDV is widespread in dogs in Mosul city, Iraq and all tests used in this study are efficient for detection CDV based on compatibility between them.

Macroscopic Distribution, Histopathology and Viral Antigen Expression in Dogs with Canine Distemper Virus-induced Hyperkeratosis in Nasodigital and Other Regions

Cutaneous hyperkeratosis is one of the many clinicopathological manifestations of canine distemper and is characterized by thickening and hardening of the skin, predominantly in nasodigital areas. Although this lesion may rarely affect other regions, this has been poorly characterized. Twelve dogs with canine distemper and cutaneous hyperkeratosis, necropsied at an anatomical pathology service, were investigated. Twenty-two cutaneous hyperkeratotic foci were observed on footpads (11/22), nasal planum (3/22), haired skin on the snout (2/22), periocular region (2/22), ventral abdomen (2/22), scrotum (1/22) and vulva (1/22). The dogs had one (5/12), two (4/12) or three (3/12) regions concomitantly affected. Orthokeratotic hyperkeratosis was a predominant histopathological feature in 17 dogs, occasionally accompanied by other lesions, including inclusion bodies (14/17), epidermal hyperplasia (9/17) and keratinocyte hydropic degeneration (6/17). Canine distemper virus antigen was expressed in at least one skin lesion in 10 dogs. Fourteen (14/17) hyperkeratotic foci were immunopositive while three (3/17) were immunonegative. Viral antigen expression was most common in the sweat glands (13/17), epidermis (11/17) and vascular endothelial cells or pericytes (8/17). Histological findings and antigen detection were similar among nasodigital and other regions. We emphasize the importance of clinicopathological recognition of these lesions for the initial suspicion of canine distemper, thereby facilitating early treatment.

Molecular and pathological screening of canine distemper virus in Asiatic lions, tigers, leopards, snow leopards, clouded leopards, leopard cats, jungle cats, civet cats, fishing cat, and jaguar of different states, India.

The present investigation was conducted to rule out canine distemper (CD) diseases in Indian wild felids (Asiatic lions, tigers, leopards, snow leopards, clouded leopards, leopard cats, jungle cats, civet cats, fishing cat, and jaguar). The collected samples were screened for CD virus (CDV) by histopathology (HP), immunohistochemistry (IHC) and reverse transcriptase-polymerase chain reaction (RT-PCR) targeting H gene and N gene. The HP and IHC of suspected samples portrayed that 22 [11 leopards, 6 lions, 3 tigers, 1 snow leopard and 1 civet cat] out of 129 (17.05%) wild felids were positive for CD. The major pathological consequences were observed in spleen, lung, kidney and brain. The syncytia and intranuclear as well as intracytoplasmic eosinophilic inclusion bodies were seen in CDV infected cells. Although the histopathological lesions in spleen were more specific and consistent, however, the severe demyelinated leukoencephalitis (usually expected in CD infected dog) was not observed in the brain of any Indian wild felids. Conversely, the CDV antigen has been portrayed via IHC in pancreatic islets of Langerhans of tiger species for the first time in this study. Moreover, the concurrent CD and babesiosis has also been observed in a lioness without a usual coffee-coloured urine. The N gene and H gene of CDV isolates were amplified, sequenced and subsequently constructed the phylogenetic tree. The phylogenetic analysis of H gene revealed that the CDV isolates from Indian lion formed separate clade with CDV isolates from Indian dog and Indian palm civet cat. Furthermore, two CDV isolates from Indian tigers formed clade with Onderstepoort vaccine strain and CDV isolates from dogs of Uttar Pradesh, USA and UK. Evidently, CDV is circulating in Indian wild felids and causing diseases in them.

Canine distemper virus and canine adenovirus type-2 infections in neotropical otters (Lontra longicaudis) from Southern Brazil.

All descriptions of infectious diseases affecting otters were published in the Northern Hemisphere, with no occurrence identified in neotropical otters (Lontra longicaudis). Consequently, a retrospective histopathological study using archival tissue samples from six free-living neotropical otters was done to investigate the possible occurrence of disease patterns associated with common viral infectious disease agents of the domestic dogs. Immunohistochemical (IHC) assays were designed to identify intralesional tissue antigens of canine distemper virus (CDV), and canine adenovirus-1 (CAdV-1) and canine adenovirus-2 (CAdV-2). The most frequent histopathological patterns diagnosed were interstitial pneumonia (83.33%; 6/5) and hepatocellular vacuolar degeneration (50%; 3/6). IHC identified intralesional intracytoplasmic immunoreactivity to CDV antigens in all otters evaluated, with positive immunolabeling occurring within epithelial cells of the lungs, stomach, kidneys, and liver, and skin. Intracytoplasmic CAdV-2 antigens were identified within epithelial cells of the peribronchial glands in four otters with interstitial pneumonia. These findings resulted in singular and simultaneous infections in these neotropical otters, represented the first report of concomitant infections by CDV and CAdV-2 in free-living neotropical otters from the Southern Hemisphere, and suggested that this mammalian species is susceptible to infections by viral disease agents common to the domestic dogs and may develop similar histopathologic disease patterns.

Canine distemper virus in wildlife in south-western Europe.

Multi-host pathogens emerging and re-emerging at the wildlife-domestic animal interface affect wildlife management and conservation. This is the case of canine distemper virus (CDV), a paramyxovirus closely related to human measles virus and rinderpest virus of cattle. With an area of 10,603 km2 , Asturias region in Atlantic Spain is a hotspot of carnivore diversity, which includes the largest Eurasian brown bear (Ursus arctos arctos) population and one of the largest wolf (Canis lupus) populations in south-western Europe. In 2020-2021, we recorded mortality due to distemper in four carnivore species including three mustelids (Eurasian badger Meles meles, European marten Martes martes and European polecat Mustela putorius) and one canid (red fox, Vulpes vulpes). Clinical signs and pathology were similar across species and consistent with the emergence of a highly pathogenic viral strain, with CDV antigen mainly located in the central nervous system, lungs, spleen and lymph nodes. A molecular study in eight wild carnivore species, also including the Iberian wolf, Eurasian brown bear, American mink (Neovison vison) and stone marten (Martes foina), revealed 19.51% (16/82) of positivity. Phylogenetic analysis demonstrated that CDV belonged to the previously described European lineage. A retrospective serosurvey (2008-2020) showed a high seroprevalence of CDV antibodies (43.4%) in 684 analyzed badgers, indicating a long-term though not stable viral circulation in this multi-host community. The possible triggers of the 2020-2021 outbreak and the implications for carnivore management and conservation are discussed.

The World Small Animal Veterinary Association (WSAVA): List of Essential Medicines for Cats and Dogs.

The World Small Animal Veterinary Association (WSAVA): List of Essential Medicines for Cats and Dogs.

Diagnosis and characterization of canine distemper virus through sequencing by MinION nanopore technology

Prompt identification of the causative pathogen of an infectious disease is essential for the choice of treatment or preventive measures. In this perspective, nucleic acids purified from the brain tissue of a dog succumbed after severe neurological signs were processed with the MinION (Oxford Nanopore Technologies, Oxford UK) sequencing technology. Canine distemper virus (CDV) sequence reads were detected. Subsequently, a specific molecular test and immunohistochemistry were used to confirm the presence of CDV RNA and antigen, respectively, in tissues. This study supports the use of the NGS in veterinary clinical practice with potential advantages in terms of rapidity and broad-range of molecular diagnosis.

Epidemiology of canine distemper in Makurdi, Nigeria

Canine distemper (CD), a major disease of dogs all over the world, hitherto controlled by extensive vaccination of dogs around the world, appears to be persisting and even re-emerging in many parts of the world. It is thought that wild life reservoir hosts contribute to the emergence of CD, but in areas of the world with minimal wildlife contact with domestic dogs, it is thought that cyclical infection between clinically normal dogs and susceptible neonatal animals may be responsible for maintaining the canine distemper virus (CDV) in the canine population. We decided to examine clinically normal dogs in the Makurdi metropolis for evidence of infection with CDV, to determine if such dogs may act as sources of persistence of the CDV in the canine population. We tested 70 unvaccinated, clinically normal dogs for evidence of distemper virus using a rapid CDV antigen (Ag) chromatographic assay test kit designed for the qualitative detection of canine distemper virus antigens in urine, conjunctiva, serum or plasma. We found six (6 or 8.6%) of the 70 dogs positive for distemper antigen; three (3) of the dogs were under one (1) year of age, whereas three were 5 years or more. We conclude that the CDV is circulating among clinically normal dogs in Makurdi, and that a cyclical infection between infected but clinically normal adult dogs and puppies may be responsible for maintaining the disease in the canine population in Makurdi. Further studies are necessary to elucidate the role of vaccination and the possibilities of emergence of new antigenic strains of CDV in the epidemiology of CD in the Makurdi area. Keywords: Canine Distemper, Vaccination, Laboratory diagnosis, maintenance in population, Makurdi, Nigeria

Inactivated Recombinant Rabies Viruses Displaying Canine Distemper Virus Glycoproteins Induce Protective Immunity against Both Pathogens.

The development of multivalent vaccines is an attractive methodology for the simultaneous prevention of several infectious diseases in vulnerable populations. Both canine distemper virus (CDV) and rabies virus (RABV) cause lethal disease in wild and domestic carnivores. While RABV vaccines are inactivated, the live-attenuated CDV vaccines retain residual virulence for highly susceptible wildlife species. In this study, we developed recombinant bivalent vaccine candidates based on recombinant vaccine strain rabies virus particles, which concurrently display the protective CDV and RABV glycoprotein antigens. The recombinant viruses replicated to near-wild-type titers, and the heterologous glycoproteins were efficiently expressed and incorporated in the viral particles. Immunization of ferrets with beta-propiolactone-inactivated recombinant virus particles elicited protective RABV antibody titers, and animals immunized with a combination of CDV attachment protein- and fusion protein-expressing recombinant viruses were protected from lethal CDV challenge. However, animals that were immunized with only a RABV expressing the attachment protein of CDV vaccine strain Onderstepoort succumbed to infection with a more recent wild-type strain, indicating that immune responses to the more conserved fusion protein contribute to protection against heterologous CDV strains.IMPORTANCE Rabies virus and canine distemper virus (CDV) cause high mortality rates and death in many carnivores. While rabies vaccines are inactivated and thus have an excellent safety profile and high stability, live-attenuated CDV vaccines can retain residual virulence in highly susceptible species. Here we generated recombinant inactivated rabies viruses that carry one of the CDV glycoproteins on their surface. Ferrets immunized twice with a mix of recombinant rabies viruses carrying the CDV fusion and attachment glycoproteins were protected from lethal CDV challenge, whereas all animals that received recombinant rabies viruses carrying only the CDV attachment protein according to the same immunization scheme died. Irrespective of the CDV antigens used, all animals developed protective titers against rabies virus, illustrating that a bivalent rabies virus-based vaccine against CDV induces protective immune responses against both pathogens.

Expression of canine distemper virus receptor nectin-4 in the central nervous system of dogs

Canine distemper virus (CDV) exhibits lymphotropic, epitheliotropic, and neurotropic nature, and causes a severe systemic infection in susceptible animals. Initially, signaling lymphocyte activation molecule (SLAM) expressed on immune cells has been identified as a crucial cellular receptor for CDV. Currently, nectin-4 expressed in epithelia has been shown to be another receptor for CDV. Our previous study demonstrated that neurons express nectin-4 and are infected with CDV. In this study, we investigated the distribution pattern of nectin-4 in various cell types in the canine central nervous system and showed its relation to CDV infection to further clarify the pathology of disease. Histopathological, immunohistochemical and immunofluorescent analyses were done using formalin-fixed paraffin-embedded tissues of CDV-infected dogs. Dual staining of nectin-4 and CDV antigen or nectin-4 and brain cell markers was performed. Nectin-4 was detected in ependymal cells, epithelia of choroid plexus, meningeal cells, neurons, granular cells, and Purkinje’s cells. CDV antigens were detected in these nectin-4-positive cells, further suggesting contribution of nectin-4 for the CDV neurovirulence. On the other hand, astrocytes did not express nectin-4, although they were frequently infected with CDV. Since astrocytes are negative for SLAM expression, they must express an unidentified CDV receptor, which also contributes to CDV neurovirulence.

Canine distemper virus antigen detection in external epithelia of recently vaccinated, sick dogs by fluorescence microscopy is a valuable prognostic indicator.

Currently, there are no reliable predictors of the clinical outcomes of domesticated dogs that have been recently vaccinated against canine distemper virus (CDV) and develop respiratory disease. In this study, vaccinated dogs from Oklahoma City that were showing clinical signs of respiratory disease were evaluated for CDV antigen using a direct fluorescent antibody test (FAT). Clinical outcomes after standard symptomatic therapy for respiratory disease were recorded, and a statistical analysis of the results was performed. We present our study showing that CDV FAT results were predictive of clinical recovery (prognostic indicator, prospects of clinical recovery) among vaccinated dogs showing clinical signs of respiratory disease. Negative CDV FAT results equated to 80% chances of recovery after symptomatic therapy, compared to 55% chances of recovery when the CDV FAT results were positive. Based on the results of this study, we show that veterinarians can make better informed decisions about the clinical outcomes of suspected CDV cases, with 2-h turnaround times, by using the CDV FAT. Thus, antemortem examination with the CDV FAT on external epithelia of recently vaccinated, sick dogs is a clinically useful diagnostic test and valuable prognostic indicator for veterinarians. Application of the CDV FAT to these samples avoids unnecessary euthanasia of dogs with suspected CDV.

Duration of Maternal Antibodies against Canine Distemper Virus and Hendra Virus in Pteropid Bats

Old World frugivorous bats have been identified as natural hosts for emerging zoonotic viruses of significant public health concern, including henipaviruses (Nipah and Hendra virus), Ebola virus, and Marburg virus. Epidemiological studies of these viruses in bats often utilize serology to describe viral dynamics, with particular attention paid to juveniles, whose birth increases the overall susceptibility of the population to a viral outbreak once maternal immunity wanes. However, little is understood about bat immunology, including the duration of maternal antibodies in neonates. Understanding duration of maternally derived immunity is critical for characterizing viral dynamics in bat populations, which may help assess the risk of spillover to humans. We conducted two separate studies of pregnant Pteropus bat species and their offspring to measure the half-life and duration of antibodies to 1) canine distemper virus antigen in vaccinated captive Pteropus hypomelanus; and 2) Hendra virus in wild-caught, naturally infected Pteropus alecto. Both of these pteropid bat species are known reservoirs for henipaviruses. We found that in both species, antibodies were transferred from dam to pup. In P. hypomelanus pups, titers against CDV waned over a mean period of 228.6 days (95% CI: 185.4–271.8) and had a mean terminal phase half-life of 96.0 days (CI 95%: 30.7–299.7). In P. alecto pups, antibodies waned over 255.13 days (95% CI: 221.0–289.3) and had a mean terminal phase half-life of 52.24 days (CI 95%: 33.76–80.83). Each species showed a duration of transferred maternal immunity of between 7.5 and 8.5 months, which was longer than has been previously estimated. These data will allow for more accurate interpretation of age-related Henipavirus serological data collected from wild pteropid bats.

Pathogenesis of Demyelinating Encephalopathy in Dogs with Spontaneous Acute Canine Distemper

So far, the pathogenesis of demyelination caused by canine distemper virus (CDV) in the central nervous system has remained unclear, although a lot of studies have been done extensively. To further investigate the relation of variety cells in brain to demyelination, this study was performed on 15 dogs with spontaneous acute canine distemper and 2 controls. According to anatomical relation, the brain was divided into cerebrum, cerebral stem and cerebellum. The sections with no, mild, moderate, or severe demyelinating lesions were selected respectively and stained by HE and immunohistochemistry. Immuno-localisation of CDV antigen was used to confirm CDV infection. The brain was examined for co-localisation of the CDV antigen with either an astrocyte-specific marker, glial fibrillary acidic protein (GFAP), or an oligodendrocyte-specific marker, galactocerebroside (GalC). Apoptotic cell was detected by TdT-mediated nick end-labeling assay (TUNEL). The results demonstrated that the local disturbance of blood circulation mainly included congestion, edema, thrombosis, and disseminated intravascular coagulation (DIC). The CDV neucleocapsid protein positive reaction, metabolic disorder and apoptosis of oligodendrocytes were observed in demyelinating areas. Lots of astrocytes displayed CDV antigen-positive, especially in their process. Some of them became apoptotic cell confirmed by TUNEL staining. Fibrous astrocytes showed more intense GFAP-positive in mild and moderate demyelinating area. Some of nervous cells located in pyramidal cell layers and nucleus nervi were in degeneration, necrosis. Satellitosis, neuronophagia and apoptotic neurons were examined by hematoxylin and eosin (HE) and TUNEL staining. The results suggested that the demyelinating changes in brain tissues infected with CDV mainly related to the metabolic disorder and apoptosis of ogliodendrocytes and astrocytes; also involved with the local disturbance of blood circulation and some neuron lost.

Simultaneous Detection of Canine Respiratory Disease Associated Viruses by a Multiplex Reverse Transcription-Polymerase Chain Reaction Assay

A multiplex reverse transcription polymerase chain reaction (mRT-PCR) assay was developed for the simultaneous detection of canine distemper virus (CDV), canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV). These viral pathogens are all causative agents of canine infectious respiratory disease (CIRD). The sensitivity and specificity of the mRT-PCR were determined by comparing it to a rapid antigen test (RAT) or immuno-chromatography test kit and reverse transcription-polymerase chain reaction (RT-PCR) in the detection of CDV, CRCoV and CIV antigens present in 100 clinical samples (nasal swabs and whole blood samples) from 50 dogs with respiratory disease symptoms. This study revealed that mRT-PCR had almost exactly the same performance or results were almost 100% in agreement with that of RT-PCR and RAT both in terms of the assay sensitivity and specificity which was more highly evident in detecting CIV, CDV and CRCoV antigens present in canine nasal swab samples. Therefore, this assay could be a better alternative for the definitive and simultaneous ante-mortem detection of the three viral pathogens that cause CIRD by using nasal swabs.