Detection of granulocytic Ehrlichia species DNA by PCR in persistently infected dogs

Three female beagle dogs inoculated with granulocytic Ehrlichia species were monitored for four to six months to determine whether there was evidence that the organisms persisted. The dogs were inoculated intravenously with blood containing an Ehrlichia species closely related to Ehrlichia equi and Ehrlichia phagocytophila, and identical to the human granulocytic ehrlichiosis agent with respect to its 16S rRNA gene sequence. The clinical signs were evaluated, and blood samples were collected for haematology, serum biochemistry and serology. Ehrlichial inclusions in the blood were monitored by microscopy, and ehrlichial DNA was detected by the polymerase chain reaction (PCR). Two of the dogs were injected with prednisolone on days 54 to 56 and days 152 to 154 after infection, and the other was injected with prednisolone on days 95 to 97 after infection. The dogs were euthanased and examined postmortem. Ehrlichial inclusions were demonstrated in the neutrophils and seroconversion occurred shortly after inoculation. Two of the dogs developed acute disease with rectal temperatures above 39.0 degrees C, after which no further clinical signs were observed. The administration of corticosteroids seemed to facilitate the detection of ehrlichial inclusions. Ehrlichial DNA was detected intermittently by PCR in blood samples from two of the dogs throughout the study. Persistent infection was demonstrated up to five-and-a-half months after inoculation.     

RELATIONSHIP AMONG BASILAR ARTERY RESISTANCE INDEX, DEGREE OF VENTRICULOMEGALY, AND CLINICAL SIGNS IN HYDROCEPHALIC DOGS

Forty-four transcranial Doppler ultrasound studies were performed in 36 dogs. The ratio of the height of the ventricle to the height of the brain (VB ratio) was calculated to determine the severity of ventriculomegaly. Resistance index (RI) was calculated from Doppler measurements of the blood flow velocity in the basilar artery and neurologic signs were scored on a scale of 0 to 3. Based on clinical and ultrasonographic findings, dogs were divided into four groups (normal controls, asymptomatic hydrocephalus, symptomatic hydrocephalus, and other intracranial disease). RI and VB ratio were compared between the groups of dogs and compared with neurologic signs in hydrocephalic dogs. RI ranged from 0.50 to 0.81 (mean, 0.68). Resistance index was significantly higher in dogs with symptomatic hydrocephalus and other intracranial disease when compared with the other two groups. The degree of ventriculomegaly was significantly higher in dogs with symptomatic hydrocephalus than the other groups, but there was substantial overlap between asymptomatic and symptomatic hydrocephalus groups. Combining measurements of VB ratio and RI allowed detection of symptomatic hydrocephalus with a sensitivity of 77% and a specificity of 94%. The severity of neurological signs was significantly correlated with RI and with VB ratio in hydrocephalic dogs, and in dogs evaluated on more than one occasion, changes in neurologic status were accompanied by changes in RI but not in VB ratio. All asymptomatic hydrocephalic dogs with a VB ratio of greater than 60% eventually developed neurologic signs. Our results suggest that ultrasonographic measurement of VB ratio and basilar artery RI may allow identification of dogs with symptomatic hydrocephalus or dogs that are at risk of developing symptomatic hydrocephalus. Repeated RI measurements are a useful means of monitoring dogs with a variety of intracranial diseases.     

Seroconversion of pigs in contact with dogs exposed to canine coronavirus.

In order to determine if canine coronavirus (CCV) could be transmitted to pigs, two dogs were inoculated orally with virulent CCV. After 24 h, the dogs were moved to an isolation room that contained three three-day-old pigs. A wire mesh fence, allowing close contact between the animals, separated the dogs from the pigs. The dogs and pigs were observed for 14 days for clinical signs of disease. Samples of blood were obtained from dogs and pigs immediately before the dogs were inoculated with virus and 14 and 28 days later. The dogs developed mild clinical signs of an infection, but the pigs remained normal throughout the observation period. The dogs shed CCV for eight days after exposure. All three pigs developed neutralizing antibodies against CCV and transmissible gastroenteritis virus by 14 days after they were exposed to the dogs.     

Clinical, clinicopathologic, and parasitologic observations of trypanosomiasis in dogs infected with North American Trypanosoma cruzi isolates

Nineteen purebred Beagles of various ages (4, 5, 13, and 47 weeks) were inoculated with North American Trypanosoma cruzi isolates obtained from an opossum (Tc-O), an armadillo (Tc-A), or a dog (Tc-D). Dogs were grouped on the basis of clinical outcome of infection. During the acute stage of disease, dogs of group 1 (n = 7 inoculated with Tc-O or Tc-A) died or were euthanatized because of the severity of disease. Dogs of group 2 (n = 5 inoculated with Tc-O or Tc-A) developed acute disease, but survived to develop chronic disease. Dogs of group 3 (n = 7 Tc-D-inoculated dogs) developed neither acute nor chronic disease. Dogs of group 4 (n = 4--2 dogs 13 weeks old and 2 dogs 47 weeks old) served as noninoculated controls. Clinical signs associated with severe acute myocarditis developed in dogs of groups 1 and 2 between postinoculation day (PID) 15 and 28. Generalized lymphadenopathy and lymphocytosis were observed in all dogs of groups 1, 2, and 3 between PID 14 and 17. Serum alanine transaminase and aspartate transaminase activities and urea nitrogen concentration were high, and glucose concentration was low prior to death of dogs in group 1. Serum activities of isoenzymes of creatine kinase were significantly (P less than 0.05) high in only 1 dog (group 1), whereas serum lactate dehydrogenase isoenzyme activities were not significantly high in any dog.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical technique, postoperative complications and outcome in 14 dogs treated for hydrocephalus by ventriculoperitoneal shunting

Objective: To report frequency and type of complications, and outcome in dogs with severe neurologic signs secondary to internal, suspected obstructive hydrocephalus treated by ventriculoperitoneal (VP) shunting. Study Design: Case series. Animals: Dogs (n=14). Methods: Medical records (2001–2006) was reviewed for dogs that had VP shunting. Inclusion criteria were complete medical record, progressive forebrain signs unresponsive to medical treatment, normal metabolic profile, negative antibody titers and/or cerebrospinal PCR for Toxoplasma gondii, Neospora caninum, and canine distemper virus, magnetic resonance images of the brain, confirmed diagnosis of VP shunting, and follow‐up information. Results: Hydrocephalus was idiopathic in 5 dogs and acquired (interventricular tumors, intraventricular hemorrhage, inflammatory disease) in 9 dogs. Four dogs developed complications 1 week to 18 months postoperatively, including ventricular catheter migration, infection, shunt under‐drainage, kinking of the peritoneal catheter, valve fracture, and abdominal skin necrosis. Three of these dogs had 1 or more successful revision surgeries and 1 dog was successfully treated with antibiotics. All, but 1 dog, were discharged within 1 week of surgery, and had substantial neurologic improvement. Median survival time for all dogs was 320 days (1–2340 days), for dogs with idiopathic hydrocephalus, 274 (60–420) days and for dogs with secondary hydrocephalus, 365 (1–2340) days. Conclusions: VP shunting was successful in relieving neurologic signs in most dogs and postoperative complications occurred in 29%, but were resolved medically or surgically.     

Brain lesions and transmission of experimental equine herpesvirus type 9 in pigs

We demonstrated that pigs are susceptible to acute infection by equine herpesvirus type 9 (EHV-9). Six 8-week-old SPF pigs were inoculated intranasally and four were inoculated orally with different doses of EHV-9, and observed for 6 days. Although neurological signs did not develop in any of the infected pigs, the six intranasally infected pigs and one of the orally infected pigs developed lesions of encephalitis consisting of neuronal necrosis, neuronophagia, and intranuclear inclusion bodies, distributed mainly in the rhinencephalon. EHV-9 antigen was localized in the necrotic neuronal cells and was closely associated with the presence of inclusion bodies. These findings clearly demonstrate that pigs are fully susceptible to EHV-9 infection following intranasal inoculation (but less so following oral inoculation), and that EHV-9 in pigs has a highly neurotropic nature.     

Experimental infection of equine herpesvirus 9 in dogs

Equine herpesvirus 9 (EHV-9), a new neurotropic equine herpesvirus, was inoculated intranasally at 107 plaque-forming units in five dogs to assess its pathogenicity. Dogs showed weight loss, pyrexia, anorexia, and neurologic signs on the fourth day. The EHV-9 virus was recovered from the examined brains. Histologically, dogs had a fulminant nonsuppurative encephalitis characterized by severe neuronal degeneration and loss, with intranuclear inclusions, slight glial reactions, perivascular cuffing, and multifocal hemorrhage. The olfactory bulb and the frontal and temporal lobes were predominantly affected. Immunohistochemistry revealed reactivity for EHV-9 antigen in neurons. All dogs had mild bronchopneumonia and various degrees of lymphoid necrosis. These findings indicate that dogs are fully susceptible to EHV-9 and that EHV-9 can cause fulminant encephalitis with high mortality in dogs, as in gazelles and goats.     

ULTRASONOGRAPHIC DIAGNOSIS OF CANINE HYDROCEPHALUS

The brains of 23 canine patients and six random-source dogs were examined ultrasonographically through the bregmatic fontanelle or a surgical craniotomy. Fifteen dogs had abnormal neurologic signs; the others were normal on neurologic examination. Untrasound results were compared with signalment, clinical signs, electroencephalography, computed tomography, radiology and histopathology. The purposes of the study were to demonstrate the use of ultrasound for the diagnosis of canine hydrocephalus and to determine whether there is a relationship between ventricular size and clinical signs. Lateral ventricles were considered enlarged if lateral ventricular height, ventricle-mantle ratio, or ventricle-hemisphere ratio, at the level of or caudal to the interthalamic adhesion in the transverse plane, exceeded 0.35 cm, 0.25 or 0.19, respectively. Of the 29 dogs examined, 14 had enlarged lateral ventricles and abnormal neurologic signs. Five dogs had enlarged lateral ventricles but appeared neurologically normal (occult hydrocephalus). Correlation was poor between ventricular size and clinical signs.     

Experimental acute canine monocytic ehrlichiosis: clinicopathological and immunopathological findings

Clinical signs, humoral and cellular immune responses, and microscopic and gross tissue alterations resulting from acute experimental Ehrlichia canis infection in dogs were studied. Four dogs were inoculated with E. canis and four were used as uninfected controls. After a 10-14-day incubation period, infected dogs developed pyrexia up to 41 degrees C for 6-8 days. Antibody titers to E. canis antigen were demonstrable in all inoculated dogs at 30 days post-infection. Necropsy of infected animals revealed pale mucous membranes, generalized lymphadenopathy, splenomegaly, edema and ascites. Microcopically, the main lesions were: lymphoreticular hyperplasia in cortical areas of lymph nodes and spleenic white pulp, periportal accumulation of mononuclear cells and centrolobular fatty degeneration of the liver. Kidneys presented with glomerulonephritis characterized by interstitial mononuclear infiltration. Immunophenotyping of lymphocytes from lymph nodes and spleen sections displayed alterations in IgG, IgM, CD3+ and CD8+ cells population in infected dogs.     

Evaluation of jackrabbits as nonruminant hosts for Anaplasma marginale

Two black-tailed jackrabbits (Lepus californicus), 1 splenectomized and 1 intact, were inoculated with 0.2 ml of a 1:5 dilution of a Florida Anaplasma marginale stabilate. Five months later, both hares were inoculated with 1 ml of whole blood from a calf with acute anaplasmosis. Neither hare developed any signs of clinical anaplasmosis. Pooled blood (7 ml) from these jackrabbits which was inoculated into 2 Anaplasma-susceptible, splenectomized calves failed to induce hematologic or serologic signs of anaplasmosis for at least 90 days. Two susceptible, splenectomized calves were inoculated with 35 ml of pooled whole blood from 9 wild-collected black-tailed jackrabbits from a known anaplasmosis enzootic area. Both steers remained free of anaplasmosis signs for 90 days.     

Comparative virulence of NAD-dependent and NAD-independent Actinobacillus pleuropneumoniae strains.

The virulence of a NAD-independent Actinobacillus pleuropneumoniae serotype 2 strain and NAD-dependent serotype 2, 3 and 9 strains was compared under experimental conditions. Hysterectomy-derived piglets were inoculated endobronchially with 50-500 cfu of these strains. All 23 piglets inoculated with the NAD-dependent strains developed acute disease within 12 hours post inoculation. Twenty-two of these piglets died within 24 hours after the first clinical signs. Three of nine piglets inoculated with the NAD-independent strain did not develop clinical disease. In the other six piglets, disease signs were similar as in the piglets inoculated with the NAD-dependent strains. No differences in clinical disease were observed between colostrum deprived piglets and piglets that obtained colostrum from a SPF sow.     

Results of pacemaker implantation in 104 dogs

OBJECTIVES: To document the outcome, survival and complications involved in pacemaker implantation in dogs in a retrospective study. METHODS: Case records for all dogs in which pacemaker implantation was performed were reviewed. RESULTS: A total of 104 dogs underwent pacemaker implantation. Dogs were presented with atrioventricular (AV) block (71), sick sinus syndrome (25) or vasovagal syncope (eight). Age at presentation varied from six months to 13 years with a median age of seven years and two months. The Labrador was the most commonly represented breed (17 cases). All but one dog survived pacemaker implantation, with 93 showing resolution of their clinical signs while 10 dogs showed intermittent residual signs. One-, three- and five-year survival estimates were 86, 65 and 39 per cent, respectively. Major complications after implantation were documented in 15 dogs and three of these led to fatalities. Minor complications were noted in 23 dogs. Sudden death occurred in six dogs three to 55 months following successful pacemaker implantation. CLINICAL SIGNIFICANCE: Transvenous pacemaker implantation was successful in reducing or eliminating clinical signs in over 90 per cent of dogs with third-degree atrioventricular (AV) block or sick sinus syndrome. In dogs with vasovagal syncope, six of eight dogs had greatly reduced frequency of collapse and two became asymptomatic. Although the procedure was associated with complications, these were rarely life threatening and good survival was documented in the majority of cases.     

Ureterocolonlc Anastomosis in Ten Dogs with Transitional Cell Carcinoma

Ureterocolonic anastomosis (UCA) was performed in 10 dogs with transitional cell carcinoma of the urinary bladder trigone or the urethra, or both. All grossly visible tumor was excised. All of the dogs recovered from anesthesia and surgery and had anal continence with no urine leakage. One dog died of undetermined causes 7 days after surgery. Nine dogs survived 1 to 5 months. The owners of eight of the dogs considered their dog's quality of life to be acceptable. Four dogs were euthanatized because of neurologic disease, three of which also had nausea and vomiting. The neurologic and gastrointestinal signs may have been caused by hyperammonemia, metabolic acidosis, and uremia. Blood ammonia levels were elevated in two dogs with neurologic signs. Hyperchloremic metabolic acidosis that was reversible with bicarbonate therapy was diagnosed in five dogs. All of the dogs were azotemic because of intestinal recycling of urea. Serum creatinine concentrations increased in four dogs after surgery. Drug-induced renal disease may have developed in two dogs. Pyelonephritis developed in five kidneys, two of which had outflow obstruction and two had bilateral hydroureteronephrosis before the UCA. In this small number of dogs, surgical excision of transitional cell carcinoma was not curative with six dogs having confirmed metastatic lesions at the time of death.     

Comparison of the efficacy of three commercial bacterins in preventing canine leptospirosis

Twenty-four specific pathogen-free beagles were randomly allocated into four groups (three vaccinated groups and one control group) and inoculated at nine and 12 weeks of age with one of three commercial inactivated Leptospira vaccines: A (Vanguard 7; Pfizer Santé Animale), B (Dohyvac 7L; Fort Dodge), and C (Nobivac DHPPi + Lepto; Intervet International); the control group received Nobivac DHPPi (Intervet International). Seven weeks after the second vaccination all the dogs were challenged with Leptospira interrogans serogroup canicola. All the vaccinated dogs developed a mild serological response (microscopic agglutination titres) after the booster vaccination. A significant serological response after the challenge was observed, particularly in the controls. The challenge induced fever and clinical disorders in the control group, whereas in the vaccinated groups the clinical signs were mild. Blood cultures became positive in all control dogs, and in one of six dogs vaccinated with vaccine A and two of four dogs vaccinated with vaccine B; none of the six dogs vaccinated with vaccine C was leptospiraemic at any stage of the experiment. Urine cultures were positive in all the control dogs two weeks after the challenge. One of six dogs vaccinated with vaccine A and two of four dogs vaccinated with vaccine B shed bacteria in their urine after the challenge, but none of the dogs vaccinated with vaccine C shed bacteria in their urine at any time during the experiment.     

Prevalence of antibodies to tickborne encephalitis and West Nile flaviviruses and the clinical signs of tickborne encephalitis in dogs in the Czech Republic

Blood sera from 151 dogs from areas of the Czech Republic endemic for human tickborne encephalitis (TBE) were examined for the presence of antibodies to TBE and West Nile (WN) flaviviruses by the haemagglutination-inhibition test Antibodies to TBE virus at titres equal to or exceeding 40 were found in five dogs. Antibodies to WN virus were detected in only one dog that also had a high antibody titre to TBE, suggesting this was a cross-reaction between the two closely related viruses. Three of the dogs (all rottweilers) with a TBE titre of 320 had clinical signs of meningoencephalitis or encephalitis. They all survived after treatment for the clinical signs. It was proved by seroconversion that the disease was caused by the TBE virus in one of these three dogs, and it seems very likely that the virus was responsible for the disease in the other two.     

Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone.

OBJECTIVE: To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs. ANIMALS: 22 healthy Beagles. PROCEDURE: All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure. RESULTS: Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions. CONCLUSIONS AND CLINICAL RELEVANCE: Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.     

Clinical and pathologic comparison of acute leptospirosis in dogs caused by two strains of Leptospira kirschneri serovar grippotyphosa

OBJECTIVE: To develop a method for inducing acute leptospirosis in dogs. ANIMALS: 31 nine-week-old female Beagles. PROCEDURE: Beagles were randomly assigned to 2 inoculation groups or a control group. Dogs were inoculated on 3 successive days by conjunctival instillation of 5 x 10(7) cells of Leptospira kirschneri serovar grippotyphosa strain 82 (12 dogs) or strain RM 52 (14 dogs). Control dogs (n = 5) were similarly inoculated with sterile leptospiral culture media. Clinical signs, clinicopathologic variables, anti-leptospiral antibody titers, and evidence of leptospires in tissues and body fluids were evaluated. Dogs were euthanatized and necropsied on days 7, 14, 22, or 28 after inoculation or as required because of severe illness. RESULTS: Clinical signs in infected dogs included conjunctivitis, lethargy, diarrhea, dehydration, vomiting, and icterus. Consistent clinicopathologic alterations included azotemia, hyperphosphatemia, increased anion gap, hyperbilirubinemia, and an increase in alkaline phosphatase activity. Leptospires were cultured from the kidneys (11/12), urine (6/9), aqueous humor (9/12), blood (12/12), and liver (12/12) of dogs inoculated with strain 82. Only 3 of 14 dogs became infected after inoculation with strain RM 52. Histopathologic lesions in infected dogs included interstitial nephritis, renal tubular degeneration and necrosis, pulmonary hemorrhage, and hepatic edema and perivasculitis. CONCLUSIONS AND CLINICAL RELEVANCE: Conjunctival exposure to L kirschneri serovar grippotyphosa strain 82 resulted in acute leptospirosis in all inoculated dogs, but only 3 of 14 dogs inoculated with strain RM 52 became infected. This method of infection by serovar grippotyphosa can be used to study the pathogenesis and prevention of leptospirosis in dogs.     

Susceptibility of dogs to infection with Ehrlichia risticii, causative agent of equine monocytic ehrlichiosis (Potomac horse fever)

Adult dogs 1 to 5 were inoculated IV and/or SC with 3, 5, or 6 ml of a suspension containing 1.2 x 10(4) Ehrlichia risticii-infected cells (derived from primary canine monocyte cell cultures)/ml. Dogs 6 to 8 were inoculated IV and/or SC with 3 or 6 ml of 1.2 x 10(5) organism-free cultured canine monocytes/ml. Ehrlichia risticii was isolated in cultures from inoculated dogs 3, 4, and 5 on postinoculation days (PID) 10 to 16, but not from dogs 6 to 8. Dogs inoculated with E risticii seroconverted between PID 6 and 12. Clinical signs of illness were not observed in these 5 E risticii-inoculated dogs. A pony, inoculated with E risticii isolated from inoculated dog 5, developed clinical signs of equine monocytic ehrlichiosis, including fever, anorexia, depression, and diarrhea, and E risticii was isolated from the pony's blood. This E risticii isolate was then inoculated into susceptible dog 9, and E risticii was repeatedly isolated from dog 9 during PID 6 to 17. Dogs were susceptible to infection with E risticii and may serve as a reservoir of the organism in the field.     

Hybrid balloon valvuloplasty for management of severe mitral stenosis in four symptomatic,adult dogs

Four adult dogs weighing <10 kg presented for the evaluation of severe mitral valve stenosis with clinical signs. Owing to the size of the dogs, a hybrid surgical and interventional approach was utilized for balloon valvuloplasty. A left lateral thoracotomy was performed to allow direct entry through the left atrial wall. Transesophageal echocardiography was utilized for the entirety of the procedure in all dogs, and fluoroscopy was additionally used in two dogs. One dog had mild to moderate intra-operative bleeding from the left atrial wall during the procedure, but no other intra-operative complications were observed. No dogs developed a clinically relevant amount of worsened mitral regurgitation. Based on mitral leaflet mobility and transmitral flow profiles, there was perceived improvement in all four dogs. One dog died 6 h after extubation due to respiratory arrest. The remaining dogs survived to discharge and had resolution of clinical signs at home and discontinuation of heart failure medications. One dog died of an unknown cause at five months and another developed atrial fibrillation, and the owners elected to euthanize at ten months after the procedure. One dog continues to do well six months after the procedure as of the time of this writing. Hybrid balloon valvuloplasty can be a viable management option for small breed dogs with severe mitral stenosis exhibiting clinical signs, and both transesophageal echocardiography and fluoroscopy can be used intra-operatively to assist in successful procedural outcomes.     

Studies on the role of feline calicivirus in chronic stomatitis in cats.

Two groups of cats were inoculated oro-nasally with one of two isolates of feline calicivirus (FCV) from clinical cases of chronic stomatitis. All cats developed signs typical of acute FCV infection; namely, ocular and nasal discharge, conjunctivitis, and marked oral ulceration. None of the cats shed virus beyond 28 days. Seronegative control cats were then infected with a lower dose of one isolate, but again only acute signs were seen and no carriers produced. The original cats were then re-infected with the heterologous isolate. As before, only signs of acute disease were seen, but the range of clinical signs and severity was reduced. Virus shedding patterns in one group were similar to those seen originally, but in the other the duration was reduced. No chronic stomatitis developed over the 10 months of the study. Serum virus neutralising and serum and salivary class specific immunoglobulin responses were investigated. Although long-term carriers were not induced, no relationship between cessation of virus shedding in an individual animal and systemic and local antibody responses was seen.