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.

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.

The 2000 Canine Distemper Epidemic in Caspian Seals (Phoca caspica): Pathology and Analysis of Contributory Factors

More than 10,000 Caspian seals ( Phoca caspica) were reported dead in the Caspian Sea during spring and summer 2000. We performed necropsies and extensive laboratory analyses on 18 seals, as well as examination of the pattern of strandings and variation in weather in recent years, to identify the cause of mortality and potential contributory factors. The monthly stranding rate in 2000 was up to 2.8 times the historic mean. It was preceded by an unusually mild winter, as observed before in mass mortality events of pinnipeds. The primary diagnosis in 11 of 13 seals was canine distemper, characterized by broncho-interstitial pneumonia, lymphocytic necrosis and depletion in lymphoid organs, and the presence of typical intracytoplasmic inclusion bodies in multiple epithelia. Canine distemper virus infection was confirmed by phylogenetic analysis of reverse transcriptase-polymerase chain reaction products. Organochlorine and zinc concentrations in tissues of seals with canine distemper were comparable to those of Caspian seals in previous years. Concurrent bacterial infections that may have contributed to the mortality of the seals included Bordetella bronchiseptica (4/8 seals), Streptococcus phocae (3/8), Salmonella dublin (1/8), and S. choleraesuis (1/8). A newly identified bacterium, Corynebacterium caspium, was associated with balanoposthitis in one seal. Several infectious and parasitic organisms, including poxvirus, Atopobacter phocae, Eimeria- and Sarcocystis-like organisms, and Halarachne sp. were identified in Caspian seals for the first time.

Histopathology and Immunohistochemistry of Canine Distemper Virus-induced Footpad Hyperkeratosis (Hard Pad Disease) in Dogs with Natural Canine Distemper

Hard pad disease represents an uncommon manifestation of canine distemper virus (CDV) infection with a still uncertain pathogenesis. To study the pathogenesis of this uncommon, virally induced cutaneous lesion, the footpads of 19 dogs with naturally occurring distemper were investigated for histologic changes and distribution pattern of CDV antigen. All dogs displayed clinical signs of distemper, which had lasted from 10 to 75 days. Overt digital hyperkeratosis was observed in 12 animals (group A), whereas the footpads of the remaining seven dogs appeared normal macroscopically (group B). Orthokeratotic hyperkeratosis (12/12; 100%), irregular acanthosis (11/12; 92%), thickened rete ridges (10/12; 83%), and mild mononuclear perivascular (10/12; 83%) and periadnexal (7/12; 58%) dermatitis were the most common findings in dogs with hard pad disease. Surprisingly, orthokeratotic hyperkeratosis (5/7; 71%), irregular acanthosis (5/7; 71%), and thickened rete ridges (4/7; 57%) were also seen in the dogs without clinical evidence of digital hyperkeratosis. CDV-specific inclusion bodies and ballooning degeneration were not observed in the footpad epidermis of the 19 dogs. Immunohistochemistry revealed that CDV antigen was most frequently found in the stratum spinosum and granulosum and in the epithelial cells of the eccrine sweat glands and only rarely in the basal layer. Fibroblasts, pericytes, endothelial cells, and hair follicles were also positive in some animals. Despite the obvious difference regarding the macroscopic picture, the microscopic changes were less prominent between the animal groups. The selective infection of keratinocytes in the stratum spinosum might be the key event for the development of hard pad disease in the dog.

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.

Optic neuritis caused by canine distemper virus in a Jack Russell terrier

An atypical case of canine distemper (CD) was diagnosed in a vaccinated healthy adult dog. The patient was presented circling, seizuring, and blind. Postmortem examination resulted in a diagnosis of CD. Optic neuritis was diagnosed, a finding not previously described in the context of CD virus infection presenting solely with neurological signs.

Molecular detection of Canine distemper virus and the immunohistochemical characterization of the neurologic lesions in naturally occurring old dog encephalitis

The current article describes a spontaneous case of old dog encephalitis (ODE) in a 7-year-old, intact, female Miniature Schnauzer dog from Londrina, Paraná, southern Brazil. Unlike conventional distemper encephalomyelitis, ODE is a poorly understood and extremely rare manifestation of Canine distemper virus (CDV) infection. The dog was presented with progressive clinical manifestations consistent with cerebral dysfunction. Briefly, histopathologic lesions were restricted to the forebrain and included chronic multifocal lymphoplasmacytic encephalitis with extensive perivascular cuffing, astrocytosis, and intranuclear inclusions within astrocytes and giant cells, with both intracytoplasmic and intranuclear inclusions. Immunohistochemistry (IHC) was used to identify the antigens of the nucleoprotein (NP) of CDV and to detect cluster of differentiation (CD)3, CD79a, macrophage (MAC) 387, glial fibrillary acidic protein, and vimentin to characterize the neuroparenchymal lesions. By IHC, CDV NP was demonstrated predominantly within neurons and astrocytes. Cells that formed perivascular cuffs and some astrocyte-like cells reacted intensely to vimentin. Reverse transcription polymerase chain reaction assay from brain sections further confirmed a role for CDV in this disease by the amplification and partial sequence analysis of the NP gene. These findings confirmed simultaneous detection of CDV in ODE by IHC and molecular assays. In addition, results of the current study could contribute to the neuropathologic characterization of this rare manifestation of CDV.

Climate extremes promote fatal co-infections during canine distemper epidemics in African lions

Extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. Here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. A 1994 canine distemper virus (CDV) epidemic in Serengeti lions (Panthera leo) coincided with the death of a third of the population, and a second high-mortality CDV epidemic struck the nearby Ngorongoro Crater lion population in 2001. The extent of adult mortalities was unusual for CDV and prompted an investigation into contributing factors. Serological analyses indicated that at least five “silent” CDV epidemics swept through the same two lion populations between 1976 and 2006 without clinical signs or measurable mortality, indicating that CDV was not necessarily fatal. Clinical and pathology findings suggested that hemoparsitism was a major contributing factor during fatal epidemics. Using quantitative real-time PCR, we measured the magnitude of hemoparasite infections in these populations over 22 years and demonstrated significantly higher levels of Babesia during the 1994 and 2001 epidemics. Babesia levels correlated with mortalities and extent of CDV exposure within prides. The common event preceding the two high mortality CDV outbreaks was extreme drought conditions with wide-spread herbivore die-offs, most notably of Cape buffalo (Syncerus caffer). As a consequence of high tick numbers after the resumption of rains and heavy tick infestations of starving buffalo, the lions were infected by unusually high numbers of Babesia, infections that were magnified by the immunosuppressive effects of coincident CDV, leading to unprecedented mortality. Such mass mortality events may become increasingly common if climate extremes disrupt historic stable relationships between co-existing pathogens and their susceptible hosts.

Simultaneous canine distemper virus, canine adenovirus type 2, and Mycoplasma cynos infection in a dog with pneumonia

The present case is the first description of a triple infection with canine distemper virus (CDV), canine adenovirus (CAV) type 2, and Mycoplasma cynos in a dog. The 5-month-old female Miniature Pinscher was euthanized because of dyspnea, croaking lung sounds, weight loss, and lymphopenia. Pathologic examination revealed a fibrinous necrotizing pneumonia with large amphophilic intranuclear and acidophilic intracytoplasmatic inclusion bodies in different lung cells. Immunohistochemically, CDV antigen was present in lung and many other organs. In situ hybridization for detection of CAV nucleic acid showed positive signals in the lung only. Polymerase chain reaction of lung tissue and consecutive sequencing of the amplification product identified CAV type 2. Bacteriologic examination of lung tissue yielded large amounts of M cynos. This infection was confirmed by immunohistochemistry detecting abundant positive signals in the lung tissue.

Combined distemper-adenoviral pneumonia in a dog

A 3 1/2-month-old pug with oculonasal discharge and seizures was submitted for postmortem examination. Grossly, the lungs had cranioventral consolidation, and microscopically, 2 distinct types of inclusion bodies compatible with Canine distemper virus and Canine adenovirus type 2. Presence of both viruses was confirmed via immunohistochemical staining.

Toxoplasma gondii genotyping in a dog co-infected with distemper virus and ehrlichiosis rickettsia

This paper reports a toxoplasmosis, erhlichiosis and distemper co-infection in a dog with an exuberant neuropathological clinical picture. Primary involvement was discussed based on information collected in the analysis of the clinical case, such as neurological impairment, epidemiological data, poor immunoprophylactic scheme of the dog affected and the role of these diseases on immunosuppression. Canine distemper and ehrlichiosis were diagnosed based on epidemiologic data, clinical signs, hematological and cytological evaluation. Toxoplasma gondii was isolated and genetically characterized as Type I using restriction analysis (RFLP) with SAG-2 genes. Immunosuppression features of both dogs and human beings are discussed, as well as implications on animal and public health. This is the first report on toxoplasmosis, ehrlichiosis and distemper co-infection in a dog in Brazil, associated with genotyping determination of the T. gondii strain involved.

Neospora caninum infection in a free-ranging raccoon (Procyon lotor) with concurrent canine distemper virus infection

During a canine distemper virus (CDV) outbreak in raccoons (Procyon lotor) from Cook County, Illinois, a juvenile female suffering from seizures was killed and necropsied. Gross and histologic findings of necrotizing encephalitis and proliferative bronchopneumonia were attributed to CDV infection and considered the cause of clinical signs. A section of cerebellum stained immunohistochemically for Neospora caninum revealed an approximately 40 microm diameter, round to oval cyst with a 2- to 3-microm-thick wall and filled with 1-2 microm diameter, round to oval bradyzoites. Polymerase chain reaction (PCR) results were positive for N. caninum using DNA extracted from the brain. Specific PCR for the closely related organisms Toxoplasma gondii and Hammondia heydorni yielded negative results. This case report provides histologic, immunohistochemical, and molecular evidence that raccoons are a naturally occurring intermediate host of N. caninum.

Clinicopathological findings in dogs with distemper encephalomyelitis presented without characteristic signs of the disease

The clinical diagnosis of distemper is difficult in dogs presented with nervous deficits in the absence of extraneural signs and myoclonus. The aim of this study is to verify how the clinicopathological findings may suggest distemper encephalomyelitis in such cases. We prospectively investigated 20 necropsied dogs presented with neurological signs without those characteristic signs of distemper at the time of hospital admission. Eight out of 20 dogs were diagnosed with distemper encephalomyelitis at post mortem by reverse transcription-polymerase chain reaction (RT-PCR) and histological examination. Cerebellar and/or vestibular signs progressing to tetraparesis/plegia were frequent neurological signs. Abnormalities in hematologic findings were non-specific, nevertheless the cerebrospinal fluid evaluation could suggest canine distemper virus (CDV) infection by a lymphocytic pleocytosis. At post mortem chronic CDV encephalomyelitis was predominant. Our clinical results, as well as the predominance of chronic encephalomyelitis, differ from other studies about CDV encephalomyelitis with naturally infected dogs presenting extraneural signs and myoclonus.

[Can obesity be infectious?]

Currently the presence of obesity is increasing and it has become the basic civilisation illness of our times. Up to date no attention has been paid to the possibility of etiology of infectious obesity. Recently some publications have appeared whose authors suggest a possibility of an infectious derivation of some forms of obesity. Six pathogens causing obesity in animals have been described: canine distemper virus (CDV), avian adenovirus, Borna disease virus (BDV), SMAM-1, human adenovirus Ad-36, scrapie agent, Rous-associated virus-7 (RAV-7). Among them two viruses occur in humans: human adenovirus Ad-36 and avian adenovirus SMAM-1.

Non-cytocidal infection of keratinocytes by canine distemper virus in the so-called hard pad disease of canine distemper

A late, but not uncommon sequel to canine distemper virus (CDV) infection of dogs is thickening of footpads and nasal planum, the so-called hard pad disease, originally described as vacuolar degeneration of epidermal keratinocytes with inclusion body formation and massive hyperkeratosis. However, in a recent study of footpads of naturally CDV-infected dogs only hyperkeratosis was observed without any of the other changes. Instead, acanthosis was frequently noticed. CDV nucleoprotein was present in the suprabasal keratinocytes and eccrine epithelial glands only. No CDV nucleoprotein was present in basal keratinocytes. This observation in combination with lack of obvious cytocidal changes strongly suggested the possibility of a restricted viral infection with presence of viral mRNA but without protein expression. Therefore, the presence of CDV nucleoprotein mRNA was investigated using in situ hybridization and compared to the localization of the nucleoprotein in footpads of clinically healthy and distemper dogs. Viral nucleoprotein and nucleoprotein mRNA in nearly all cases co-localized to the same compartments and basal keratinocytes did not contain nucleoprotein mRNA. These findings dispute the idea of a restricted viral infection of footpad keratinocytes in dogs with natural CDV infection. Instead, a migration of the virus to the epidermal surface along with the proliferating and differentiating epithelium is the most likely explanation for the lack of virus antigen in basal keratinocytes.

A new paraclinical CSF marker for hypoxia-like tissue damage in multiple sclerosis lesions

Recent studies on the immunopathology of multiple sclerosis revealed a heterogeneity in the patterns of demyelination, suggesting interindividual differences in the mechanism responsible for myelin destruction. One of these patterns of demyelination, characterized by oligodendrocyte dystrophy and apoptosis, closely mimics myelin destruction in acute white matter ischaemia. In the course of a systematic screening for virus antigen expression in multiple sclerosis brains, we identified a monoclonal antibody against canine distemper virus, which detects a cross-reactive endogenous brain epitope, highly expressed in this specific subtype of actively demyelinating multiple sclerosis lesions with little or no immunoreactivity in other active multiple sclerosis cases. The respective epitope, which is a phosphorylation-dependent sequence of one or more proteins of 50, 70 and 115 kDa, is also expressed in a subset of active lesions of different virus-induced inflammatory brain diseases, but is present most prominently and consistently in acute lesions of white matter ischaemia. Its presence is significantly associated with nuclear expression of hypoxia-inducible factor-1 alpha within the lesions of both inflammatory and ischaemic brain diseases. The respective epitope is liberated into the CSF and, thus, may become a useful diagnostic tool to identify clinically a defined multiple sclerosis subtype.

Pulmonary sarcocystosis in a puppy with canine distemper in Costa Rica

Canine distemper and pulmonary sarcocystosis were diagnosed in a 10-week-old Rottweiler with 4-day history of diarrhea, vomiting, and weakness. Microscopic examination of the lung revealed bronchointerstitial pneumonia typical of morbillivirus infection. Also, numerous apicomplexan parasites were scattered in the alveolar walls. This protozoan infection was first thought to be toxoplasmosis but immunoperoxidase staining revealed large numbers of Sarcocystis canis. This is the first case of canine sarcocystosis reported from Latin America that further emphasizes the importance of immunohistochemistry in the differential diagnoses of apicomplexan infections in dogs.

Relation of clinical signs to pathological changes in 19 cases of canine distemper encephalomyelitis

In an attempt to associate the clinical neurological syndromes with the neuropathological features of canine distemper (CD), 19 spontaneous cases with neurological involvement were examined, before and after euthanasia. Seventeen dogs were less than one year of age and all except two (89.4%) were unvaccinated against CD. Various extraneural signs associated with CD encephalomyelitis (CDE) were seen in 15 dogs. Generalized or localized myoclonus was the most common sign observed (13/19). Seventeen of the dogs presented with signs suggestive of one neuroanatomical location of lesions. Of these animals, seven had signs of cerebral, two of cerebellar, four of cervical, one of cervicothoracic, two of thoracolumbar and two of lumbosacral syndrome. The diagnosis of CD was confirmed immunohistochemically (detection of CD viral antigen), serologically (neutralizing serum antibody titre > or = 16) and histopathologically (CDV inclusion bodies, type of central nervous system lesions). An association of the neuroanatomical lesion location and the histopathological findings was noted in 14 out of 17 dogs (82.3%). Myoclonus could be attributed to lower motor neuron damage in eight out of 13 dogs (61.5%).

Multiple sclerosis and age at infection with common viruses

Increased risk of multiple sclerosis has been reported among individuals with a history of measles and other common childhood diseases during adolescence, infectious mononucleosis, or exposure to the canine distemper virus. We investigated these associations in a case-control study nested within the Nurses' Health Study (121,700 women traced since 1976) and the Nurses' Health Study II (116,671 women traced since 1989). Age at diagnosis of common viral diseases and birth order were obtained through a questionnaire. Our results include 301 cases with multiple sclerosis and their (up to six) matched controls. Except for infectious mononucleosis, which was a moderate risk factor (odds ratio = 2.1, 95% confidence interval = 1.5-2.9), we found little association between history of common viral diseases or exposure to canine distemper virus and risk of multiple sclerosis. We did find a relation between mumps after 15 years of age (odds ratio = 2.3, 95% confidence interval = 1.2-4.3) or measles after age 15 years of age (odds ratio = 2.8, 95% confidence interval = 0.8-9.1) and multiple sclerosis. Birth order was not materially related to multiple sclerosis. Our findings support the hypothesis that individuals who suffered from infectious mononucleosis, a marker of late infection with the Epstein-Barr virus, have an increased risk of multiple sclerosis. Late infection with other common viruses may also be associated with increased risk.

Canine distemper in a genet (Gennetta gennetta), associated with endogenous lipid pneumonia

This report describes the histological and immunohistochemical findings in an adult male genet (Gennetta gennetta) which died a few hours after being found lying in a forest in Lugo (north-western Spain). Subpleural, yellowish, firm foci were found in the lung. Histopathological examination confirmed a diagnosis of endogenous lipid pneumonia. Microscopical lesions that gave rise to a suspicion of canine distemper virus (CDV) infection included lymphoid depletion, non-suppurative encephalitis and demyelination in the central nervous system, and the presence of inclusion bodies in renal tubules. Immunohistochemical examination was performed with the streptavidin-biotin-complex method and a monoclonal antibody against the nucleocapsid protein (NP) of CDV. Antigen was detected in epithelial, nervous and lymphoid cells in several organs. This would appear to be the first report of distemper-like infection in a genet.

Listeriosis in a raccoon dog (Nyctereutes procyonoides) associated with canine distemper

A wild raccoon dog (Nyctereutes procyonoides) that manifested severe illness and died was examined. Necropsy revealed severe emaciation, systemic icterus and petechial hemorrhages on the mucous membranes. Histopathologically, necroses were seen in the liver and brain stem associated with meningitis. Eosinophilic intranuclear inclusion bodies were observed in the spleen and intestinal mucosa, and eosinophilic intracytoplasmic inclusion bodies were seen in transitional epithelium in the bladder. Listeria monocytogenes 4b was isolated from the liver, spleen, kidneys and lungs, and the pathogen was also detected in the liver and brain stem immunohistopathologically. The disease was diagnosed as listeriosis associated with canine distemper virus infection in a raccoon dog.

Pneumocystosis associated with canine distemper virus infection in a mink

An adult mink from a farm experiencing 100% mortality in affected animals was submitted for diagnostic examination. Clinical history included signs of respiratory disease, oculonasal discharge, and thickening of footpads. Canine distemper virus and Pneumocystis carinii were identified in lung tissue, suggesting immunosuppresion and secondary infection due to morbillivirus disease.

Fatal visceral and neural sarcocystosis in dogs

This paper describes acute visceral and neural sarcocystosis in four dogs. One animal was simultaneously infected with distemper virus, and another with Blastomyces dermatitidis. Schizonts and merozoites of Sarcocystis canis were found in the lesions. 1999 W.B. Saunders and Company Ltd.

A case of narcolepsy-cataplexy associated with distemper encephalitis

Narcolepsy associated with localized brain lesions is described in a 10-month-old Argentine Dogo. Neurological examination and MRI study suggested an inflammatory lesion of the left frontal lobe. Postmortem examination revealed diffuse encephalitis in the forebrain and marked necrotic lesions in the ventral pontine area. Immunohistochemistry for distemper virus antigen showed positive staining of the cytoplasm of many neurones of the pons and cerebral cortex. The pathological pattern was suggestive of post-vaccinal distemper encephalitis and the localization of the lesions was consistent with the neurological syndrome shown by the animal. At any event, the possibility of coincidental findings of distemper encephalitis and idiopathic narcolepsy must be accounted for.

Identification of CD4+ and CD8+ T cell subsets and B cells in the brain of dogs with spontaneous acute, subacute-, and chronic-demyelinating distemper encephalitis

CD4 and CD8 antigen expression of T cells as well as B cell and canine distemper virus (CDV) antigen distribution were immunohistologically examined in the cerebellum of dogs with spontaneous distemper encephalitis. Cellular and viral antigen expression were evaluated at intralesional and extralesional sites and in the perivascular space. Histologically, acute and subacute non-inflammatory encephalitis and subacute inflammatory and chronic plaques were distinguished. Demyelination was a feature of all subacute and chronic lesions, although the majority of plaques exhibited no or only a low level of active demyelination as demonstrated by single macrophages with luxol fast blue positive material in their cytoplasm. CDV antigen expression, observed in all distemper brains, was reduced in chronic plaques. CD4+, CD8+, and B cells were absent in controls and in some brains with acute encephalitis. A mild infiltration of CD8+ cells was noticed in the neuropil of the remaining brains with acute and all brains with subacute non-inflammatory encephalitis. Single CD4+ cells were found in two brains with acute and in all brains with subacute non-inflammatory encephalitis. Numerous CD8+ and CD4+ cells and few B cells, with a preponderance of CD8+ cells, were detected in subacute inflammatory and chronic lesions. In contrast, in perivascular infiltrates (PVI) of subacute and chronic lesions a dominance of CD4+ cells was detected. The dominating CD8+ cells in acute and subacute non-inflammatory encephalitis might be involved in viral clearance or contribute as antibody-independent cytotoxic T cells to early lesion development. In subacute inflammatory and chronic lesions CD8+ cells may function as cytotoxic effector cells and CD4+ cells by initiating a delayed-type hypersensitivity reaction. The simultaneous occurrence of perivascular B and CD4+ cells indicated that an antibody-mediated cytotoxicity could synergistically enhance demyelination. Summarized, temporal and spatial distribution of CD4+, CD8+ and B cells and virus antigen in early and late lesions support the hypothesis of a heterogeneous in part immune-mediated plaque pathogenesis in distemper demyelination.

Electroencephalographic findings of encephalitis in beagle dogs experimentally infected with canine distemper virus (CDV)

The present research study had two goals. Firstly, the effect of medetomidine/propofol on the electroencephalographic (EEG) recordings of nine SPF dogs was analysed. It was found that the basic pooled pattern of EEG recordings was characterized by a mean amplitude of 28 uV (range = 15-70 uV) and mean frequency of 1.8 Hz (range = 1-2.5 Hz), with superimposed low voltage (amplitude range = 4-20 uV; mean 14 uV) and fast activity (frequency range = 10-27 Hz; mean 18 Hz). All results were significantly constant (P < 0.05) and accurately reproducible (R = 0.70). The second goal was to investigate the value of EEG findings from dogs experimentally infected with canine distemper virus (CDV) under the same anaesthetic conditions, for the diagnosis of encephalitis. It was found that the EEG traces were characterized by high voltage, slow activity (HVSA) with superimposed low voltage, fast activity (LVFA). By comparing the mean values of amplitude and frequency for each single phase at different time intervals, it was found that only the mean value of the superimposed frequency was linearly distributed and changed significantly (P < 0.001). Thus, at least three readings should be taken from phase III of the EEG recording in order to obtain accurate values. The study has shown that electroencephalography can supply valuable information in cases of CDV encephalitis and can assist greatly in the differential diagnosis.

Occurrence of Pneumocystis carinii in canine distemper

Pneumocystis carinii is a eukaryotic opportunistic pathogen causing pneumonia (PCP) in immunosuppressed patients. It is best known in human medicine as a pathogen of AIDS pa-tients and in immunosuppressed transplant and cancer patients (Waltzer 1993).

Gastric attaching and effacing Escherichia coli lesions in a puppy with naturally occurring enteric colibacillosis and concurrent canine distemper virus infection

A puppy suffering from chronic diarrhea was humanely killed at 90 days of age. Numerous Gram-negative bacilli were found adhering to the surface of as well as within epithelial cells from the stomach to the colon. Canine distemper virus inclusions were in the epithelial cytoplasm of the esophageal, gastric, and intestinal mucosa. Typical attaching and effacing ultrastructural lesions were in the stomach, and some bacilli were in the cytoplasm of the epithelial cells. Escherichia coli, isolated from the contents of the small intestine, belonged to serotype 0118: NM and were negative for plasmid-encoded EPEC adherence factor (EAF) and positive for the E. coli attaching effacing (eae) gene. Immunohistologically, bacilli attached to the epithelium from the stomach to the colon were positive for antisera against E. coli 0118. E. coli 0118: NM inoculated into human tissue culture cells (HEp-2 cells) were attached to the surface of the cells and within the cytoplasm. This is the first report of attaching and effacing E. coli (AEEC) infection in the stomach of the dog.

Isolation of Yersinia pseudotuberculosis and Listeria monocytogenes serotype 4 from a gray fox (Urocyon cinereoargenteus) with canine distemper

In February 1993, clinical, pathological, and microbiological investigations were performed on an adult female gray fox (Urocyon cinereoargenteus) from northern Mississippi (USA). The fox had clinical signs consistent with canine distemper virus encephalitis. Eosinophilic inclusions characteristic of canine distemper virus were in the nuclei and cytoplasm of cerebral neurons and glial cells and in the cytoplasm of urinary, gastric, pancreatic and biliary epithelial cells. The liver contained multifocal microscopic nodular foci of granulomatous to pyogranulomatous inflammation and necrosis with large colonies of small Gram-negative coccobacilli. A low number of small Gram-positive bacilli were within viable-appearing Kupffer cells and hepatocytes. Yersinia pseudotuberculosis and Listeria monocytogenes serotype 4 were isolated from the liver and a mesenteric lymph node.

Distemper in wild carnivores: an epidemiological, histological and immunocytochemical study

Brain tissue from 236 wild carnivores, 146 mustelids and 90 foxes, originating from the same geographical area in southwest Germany was collected over a 2 year period between May 1989 and May 1991 and studied for the presence of canine distemper virus (CDV) antigen by immunohistochemistry. CDV antigen was found in the brains of 54 (37%) mustelids, predominantly in the cerebellar grey matter. Interestingly, no CDV infection was observed in foxes. An increasing number of CDV infections among mustelids was noted between November 1989 and November 1990, peaking in summer 1990. Histological brain lesions, demonstrated only in 45% of the CDV positive mustelids, were characterized by non-purulent encephalitis predominantly in the cerebrum and focal vacuolation of the cerebellar white matter, whereas demyelination was only rarely observed. Histological and immunocytochemical CNS findings indicate an early stage of distemper infection in these mustelids and the high percentage of CDV positive animals together with the seasonal prevalence are suggestive of a CDV epizootic among mustelids.

Multiple dental developmental abnormalities following canine distemper infection

Multiple dental developmental abnormalities (e.g., dental impaction, partial eruption, oligodontia, enamel hypoplasia, and dentin hypoplasia) in a 10-month-old, female, Tanzanian tropical mixed-breed puppy are reported. Various permanent teeth were involved. These included impacted mandibular canine and first and third premolar teeth; a partially erupted maxillary canine tooth; oligodontia of a mandibular fourth premolar tooth; enamel hypoplasia of the maxillary and mandibular canine teeth, incisors, and premolars; and dentin hypoplasia of the maxillary incisors, maxillary premolars, and mandibular premolars. The puppy had clinical canine distemper at the age of two months and had no history of any other systemic nor generalized infection prior to the time when the dental abnormalities were observed.

Dual infection with canine distemper virus and infectious canine hepatitis virus (canine adenovirus type 1) in a dog

A 72-day-old, female, Golden Retriever dog showed anorexia, coughing, nasal discharge, diarrhea and hematochezia, and died on the 15th clinical day. Pathological examination revealed dual infection with canine distemper virus (CDV) and canine adenovirus (CAV). CAV inclusion bodies occurred only in the liver, and biliary and respiratory system, whereas CDV inclusions were demonstrated in the visceral organs systematically. The CAV inclusions were associated with multifocal hepatocellular necrosis and edematous swelling of the wall of the gall bladder, suggesting infectious canine hepatitis virus (canine adenovirus type 1) infection.

Multiple oral procedures performed on a dog with distemper myoclonus

A 3-year-old male mixed-breed dog was treated for an oral defect along the rostral portion of the hard palate and an oronasal fistula secondary to a severe mandibular brachygnathism and persistent canine distemper virus associated myoclonus. This report describes the treatment using a bilateral radical premaxillectomy, oronasal fistula repair, and pulpotomy.

Canine distemper myoclonus and sleep: observation of a case

Evolution of myoclonus was analysed electromyographically throughout quiet wakefulness, NREM sleep and REM sleep in a dog with canine distemper myoclonus. Compared with quiet wakefulness, the frequency of myoclonus was decreased and the intensity of discharges in individual myoclonic bursts was also lowered during NREM sleep. When NREM sleep shifted to REM sleep, neither of these parameters was noticeably altered. However, as REM sleep continued, the former was increased markedly and the latter was further attenuated. In general, violent motor activity was concurrent in the limbs, trunk and/or head. Thus, the increase in the frequency of myoclonus seemed to be similar in nature to the phasic event during REM sleep. This indicated that lower motoneurons producing myoclonic discharges responded well to supraspinal influences. In successive myoclonic bursts, a significant and consistent positive correlation existed between the silent period and the subsequent discharge period throughout the three different levels of consciousness, that is, the longer the silent period, the longer the subsequent episode of myoclonus. Therefore, this feature may be intrinsic to myoclonic firing of lower motoneurons in canine distemper myoclonus. These findings may support the idea that hyperexcitability of the lower motoneurons is primarily responsible for the genesis of canine distemper myoclonus.

Tyzzer's disease complicated with distemper in a puppy

A Pomeranian puppy which died from diarrhea and nasal discharge showed catarrhal pneumonia, acute enteritis and focal liver necrosis. Slender bacilli were detected within ileal enterocytes and hepatocytes. A double infection with a distemper virus and Tyzzer's organism at a cellular level was seen within the ileal enterocytes.

Canine distemper infection associated with acute nervous signs in dogs

Eight vaccinated dogs suddenly developed progressive ataxia, paresis or paralysis of short duration. A histopathological examination revealed a non-suppurative meningoencephalitis suggestive of a viral infection, and immunohistochemical examination confirmed the presence of canine distemper virus antigen in five of the dogs. Distemper had not been suspected from the clinical examination of the dogs.

Prevalence of Toxoplasma gondii infection in raccoons

Serum samples from 427 raccoons (93 from Pennsylvania, 45 from New Jersey, 72 from South Carolina, 68 from Virginia, 30 from Iowa, and 119 from Ohio) were evaluated for Toxoplasma gondii antibodies in dilutions of 1:25, 1:50, and 1:500. The distribution of T gondii antibody titers was less than 1:25 for 212 raccoons (49.6%), 1:25 for 34 raccoons (7.9%), 1:50 for 117 raccoons (27.4%), and greater than or equal to 1:500 for 64 raccoons (14.9%). Tissue cysts were seen in the liver, and tachyzoites were in the brain of a raccoon with abnormal neurologic signs and concurrent infection with canine distemper virus. Organisms in the liver were stained with anti-T gondii serum, and the raccoon had a T gondii titer of 1:160 in the agglutination test.

Virus-induced obesity in mice: association with a hypothalamic lesion

In an earlier study we found that a substantial percentage of mice surviving infection with canine distemper virus (CDV) slowly developed a morbid obesity syndrome. In the present study we wished to explore the role of the virus in the development of this syndrome. The distribution of viral antigen(s) in brains of pre-obese animals shortly after intracerebral infection was mapped using immunocytochemical procedures. A distinctive pattern of cell labeling was found, extending from the anterior periventricular hypothalamus ventrally and caudally toward the posterior hypothalamus. The heaviest concentration of labeled cells was found in the arcuate-ventromedial area. Viral antigen-containing cells were not found in obese brain specimens. However, the latter revealed, by glial fibrillary acidic protein immunostaining, a gliotic lesion of the hypothalamus that approximated topographically the pattern of virus tropism. Examination of the arcuate area revealed a significant reduction in tyrosine hydroxylase immunoreactive and pro-opiomelanocortin mRNA positive perikarya. We suggest that the loss of critical populations of hypothalamic neurons as a result of an antecedent viral infection led ultimately to the development of morbid obesity.

A Sarcocystis sp.-like protozoan and concurrent canine distemper virus infection associated with encephalitis in a raccoon (Procyon lotor)

A raccoon (Procyon lotor) with signs of weakness was captured in upstate New York (USA). Despite attempted care in a rehabilitation facility, the animal died and was examined because of suspected infectious neurologic disease. The cerebrum had a marked, locally extensive, neutrophilic, necrotizing encephalitis with numerous associated intralesional protozoal organisms, and a moderate to marked multifocal perivascular nonsuppurative meningoencephalitis. Based on morphology and immunohistochemical staining, the organism was a Sarcocystis sp.-like protozoan. Rabies antigen and canine distemper virus (CDV) inclusions were not detected. However, the animal was positive for canine distemper virus based on peroxidase anti-peroxidase staining.

Viral expression in experimental canine distemper demyelinating encephalitis

We have characterized the relationship between the expression of canine distemper virus (CDV) and demyelinating lesions in the white matter of the cerebellum of experimentally infected dogs. In animals which had demyelinating lesions, CDV proteins (N, P, F and H) were expressed and infectious virus could be recovered from brain tissue. Viral proteins (N, P, F and H) were detected by monoclonal antibodies and immunocytochemistry within demyelinating lesions as well as in scattered glial cells in areas of the white matter which lacked detectable lesions. Many cell types, including astrocytes, neurons, ependymal cells, choroid plexus cells, meningeal cells and perivascular inflammatory cells were labelled for viral antigen. We conclude from our results that the mechanism of demyelination in canine distemper virus-induced encephalitis involves expression of viral gene products at the lesion site.