Atypical Histoplasma capsulatum infection in a dog

Disseminated histoplasmosis was diagnosed in a 10-year-old dog suspected of having hepatic carcinoma. Clinical abnormalities included diffuse hepatomegaly, gastrointestinal bleeding, thoracic and abdominal effusion, anemia, leukocytosis, and thrombocytopenia. Histoplasmosis characteristically is a disease of the mononuclear phagocyte system, but in this case was diagnosed by finding Histoplasma capsulatum organisms in neutrophils on the blood smear.     

Bone marrow mastocytosis in dogs with myelosuppressive monocytic ehrlichiosis (Ehrlichia canis): a retrospective study

BACKGROUND: Bone marrow mastocytosis has been reported rarely in naturally occurring canine monocytic ehrlichiosis (CME). OBJECTIVES: The aims of the present study were to estimate the prevalence and magnitude of bone marrow mastocytosis in a case series of dogs with natural CME and to assess the association, if any, between mastocytosis and the clinical severity of the disease. METHODS: Seventy-six dogs with confirmed CME (Ehrlichia canis) were included in the study. Affected dogs were allocated into group A (n = 51) without bone marrow hypoplasia and group B (n = 25) with bone marrow hypoplasia. Twenty clinically healthy Beagles not previously exposed to E canis served as controls (group C). The main inclusion criteria for group A were documentation of normocellular to hypercellular bone marrow and complete clinical cure following a 4-week treatment with doxycycline, while those for group B were bone marrow hypoplasia and lack of response to doxycycline. Bone marrow aspirate smears from all 96 dogs were Giemsa-stained and examined for the presence of mast cells, which were calculated as a percentage of 1,000 nucleated cells (NCs). The prevalence of mastocytosis was compared among the 3 groups by the Pearson's chi-square test. RESULTS: Bone marrow mastocytosis (>0.1% of NCs) was found in 5 (20%) dogs in group B (range, 0.5-2.5% of NCs; median, 1% of NCs). One dog in each of groups A and C had 0.1% mast cells in the marrow. The prevalence of bone marrow mastocytosis in dogs in group B was significantly higher (P = .004) than in groups A and C. CONCLUSION: Bone marrow mastocytosis can be seen in a substantial number of dogs with E canis-induced myelosuppression.     

Chronic canine ehrlichiosis (Ehrlichia canis): a retrospective study of 19 natural cases

Nineteen dogs from Greece with chronic ehrlichiosis were studied. The dogs exhibited bicytopenia or pancytopenia, bone marrow hypoplasia, seroreactivity to Ehrlichia canis (E. canis) antigens, and had no history of drug or radiation exposure. Anorexia, depression, severe bleeding tendencies, hypoalbuminemia, and increased serum alanine aminotransferase activity were also hallmarks of the disease. All these animals eventually died, irrespective of the treatment applied. Some dogs were also serologically positive for Rickettsia conorii, Leishmania infantum (L. infantum), and Bartonella vinsonii subspp. berkhoffii. Polymerase chain reaction testing of bone marrow samples revealed E. canis, Anaplasma phagocytophilia, Anaplasma platys, and L. infantum in some dogs. Concurrent infections did not appear to substantially influence the clinical course and final outcome of the chronic canine ehrlichiosis.     

Experimentally induced Histoplasma capsulatum infection in coyotes and a dog

Captive coyotes (Canis latrans) were inoculated intragastrically (1 coyote), and intratracheally (6 coyotes) with Histoplasma capsulatum to simulate natural routes of exposure. In addition, the infectious organism was inoculated IV into another coyote and into a dog (C familiaris) to simulate hematogenous dissemination of H capsulatum. Isolation of the pathogen from various tissue specimens, using direct plating and mouse inoculation methods, provided mycologic evidence of infection. The presence of anti-Histoplasma serum antibodies also was monitored. Of the 6 coyotes challenged intratracheally, one developed a benign pulmonary form of histoplasmosis. This coyote developed a transient cough, and intracellular yeasts typical of H capsulatum were observed microscopically in pulmonary tissue specimens. The pathogen was isolated from specimens of pulmonary tissue and associated lymph nodes. The coyote that was fed Histoplasma-infected mice (intragastric challenge) did not develop clinical disease. The coyote and the dog inoculated IV developed a multifocal, nonsuppurative infection, without clinical evidence of histoplasmosis. Pathologic findings in the coyote and dog were similar; both animals had splenitis, lymphadenitis, and petechiation of the lungs. The liver and spleen were considered the primary extrapulmonary target organs on the basis of mycologic and histologic findings.     

Serum hyperviscosity syndrome associated with Ehrlichia canis infection in a dog

A 10-year-old male Lhasa Apso was examined because of pyrexia, vomiting, weight loss, lethargy, and disorientation. The clinical and laboratory findings were supportive of a diagnosis of serum hyperviscosity syndrome associated with an Ehrlichia canis infection. After tetracycline therapy the serum hyperviscosity syndrome and E. canis infection were successfully resolved.     

Babesia canis vogeli,Ehrlichia canis,and Anaplasma platys infection in a dog

A 12‐month‐old male neutered mixed breed dog was presented with a history of diarrhea, lethargy, emaciation, polydypsia, and sniffling. Physical examination findings included pale mucous membranes, increased heart and respiratory rates, and normal rectal temperature (38°C). Hematologic abnormalities included anemia and thrombocytopenia. Biochemical abnormalities included hypoalbuminemia, hyperbilirubinemia, and elevated ALP and ALT activities. A SNAP 4Dx test result was positive for Ehrlichia canis. Babesia canis vogeli organisms were found in the peripheral blood films, while morulae of E canis were not seen. Real‐time polymerase chain reaction testing confirmed the presence of both B c vogeli and E canis organisms, and also was positive for Anaplasma platys infection. The dog recovered following treatment with doxycycline and imidocarb dipropionate, with normal hematology and biochemical profiles.     

Ocular manifestations of natural canine monocytic ehrlichiosis (Ehrlichia canis): a retrospective study of 90 cases

OBJECTIVE: To investigate the spectrum, prevalence and treatment response rate of ocular manifestations associated with natural canine monocytic ehrlichiosis (CME) due to Ehrlichia canis. METHODS: The medical records of 90 dogs that were admitted for primary ocular problems and reacted positive for E. canis serum antibodies were reviewed. All the dogs were treated with oral doxycycline. In 79 dogs, a combination of systemic corticosteroids and/or topical anti-inflammatory, mydriatics/cycloplegics and antibacterial agents were applied. RESULTS: The dogs ranged from 0.5 to 15 years in age; 55 were male and 35 female. A total of 19 breeds were represented. In the majority of dogs, ocular abnormalities were noticed in conjunction with other CME-induced clinical signs. In 30/90 dogs, ophthalmic signs were the sole presenting complaint. Unilateral (22/90, 24.5%) and bilateral (68/90, 75.5%) uveitis was the most common ophthalmic diagnosis and was classified as anterior, posterior or panuveitis in 58 (64.5%), 8 (8.9%) and 24 (26.6%) of the dogs, respectively. Bilateral uveitis was significantly more common than unilateral uveitis (P < 0.0001), and anterior significantly more common than posterior uveitis (P < 0.0001) or panuveitis (P < 0.0001). In addition, corneal ulceration (12/90, 13.3%), necrotic scleritis (10/90, 11.1%), low tear production (8/90, 8.9%) and orbital cellulitis (3/90, 3.3%) were seen. Of the 45 (50%) dogs with a satisfactory follow-up, 25 (55.5%), 11 (24.5%), and 9 (20%) showed complete, partial and poor response to treatment, respectively. The number of dogs exhibiting complete resolution of the ocular manifestations was significantly higher than those with partial (P < 0.0001) or poor (P < 0.0001) response. CONCLUSIONS: CME should be considered a major differential for a wide range of ocular manifestations exhibited by dogs residing in the endemic areas of the disease. Anterior bilateral uveitis appears to be the most prevalent ocular lesion and a favorable outcome to systemic and topical treatment may be expected in the majority of the affected dogs.     

Neurolymphomatosis in a dog with B-cell lymphoma

Lymphoma in the left femoral nerve of a 10-year-old English Cocker Spaniel caused complete paralysis of the affected limb. Neoplastic cells were immunopositive for CD79a and Pax5 and negative for CD3. Neoplastic cells were in multiple lymph nodes and one kidney but spared bone marrow. The clinical and histologic features in this case resemble those of the rare human condition of neurolymphomatosis.     

First record of autochthonous canine ehrlichiosis caused by Ehrlichia canis in Romania

This case study describes the first genetically confirmed and clinically manifested autochthonous Ehrlichia canis infection in a 9‐year‐old female mixed‐breed dog from Romania. Health screening of the dog included clinical examination, evaluation of stained peripheral blood smear and hematologic variables, as well as serologic testing and molecular analysis. Clinical signs included fever, apathy, dehydration, pale mucous membranes, and weakness. The microscopic examination of the blood smear and immunologic assays for Borrelia burgdorferi, Anaplasma phagocytophilum, and E canis antibodies, and for Dirofilaria immitis antigen yielded negative results. Hematologic abnormalities included moderate nonregenerative anemia, leucopenia with neutropenia, and moderate thrombocytopenia. The biochemical abnormalities identified were hypoalbuminemia, and mildly increased serum enzyme activities of AST and ALT. In addition, increased urea and creatinine levels associated with low urine specific gravity and proteinuria were also present. Nested PCR amplification of the partial E canis 16S rRNA gene demonstrated the presence of this rickettsial pathogen in the dog's blood, which subsequently was confirmed through sequencing based on the 100% homology with GenBank deposited E canis isolates. After specific treatment with doxycycline (10 mg/kg, orally, SID) for one month, the proteinuria, and hematologic and serum biochemical abnormalities with the exception of mild azotemia resolved. This report supports the geographical expansion of canine ehrlichiosis caused by E canis in nonendemic regions of Europe.     

Mixed Ehrlichia canis, Hepatozoon canis, and presumptive Anaplasma phagocytophilum infection in a dog

A 5-month-old, female, mongrel dog was admitted to the Clinic of Companion Animal Medicine, Aristotle University of Thessaloniki, Greece, with depression, anorexia, fever, peripheral lymphadenopathy, splenomegaly, oculonasal discharge, nonregenerative anemia, and mild thrombocytopenia. Cytology of Giemsa-stained buffy coat, bone marrow, and lymph node aspiration smears revealed numerous morulae in mononuclear leukocytes and in neutrophils, and Hepatozoon canis gamonts in neutrophils. The dog was seropositive to Ehrlichia canis (immunofluorescence assay [IFA]) and Hepatozoon canis (ELISA) but not to Anaplasma phagocytophilum (IFA). A nested polymerase chain reaction performed on bone marrow aspirates was positive for E canis. This method was not applied for the detection of A phagocytophilum. Treatment with doxycycline and imidocarb dipropionate resulted in both clinical and parasitologic cure. This is the first reported case of a mixed infection with E canis, H canis, and presumptive A phagocytophilum. The findings emphasize the value of cytology in offering a quick and inexpensive diagnosis in mixed tick-borne infections of dogs.     

Clinical evaluation of urine Histoplasma capsulatum antigen measurement in cats with suspected disseminated histoplasmosis

Diagnosis of Histoplasma capsulatum infection in cats traditionally relies upon identification of organisms in circulating monocytes or in tissue specimens from affected organs. In this retrospective study, results of a urine antigen assay were compared with standard diagnostic methods in cats with clinical signs suggestive of histoplasmosis. Antigenuria was detected in 17/18 cats with a histopathologic or cytopathologic diagnosis of histoplasmosis. This preliminary evaluation of the Histoplasma urine antigen test suggests it may be a useful aid in diagnosing this disease in cats.     

Neospora caninum and Ehrlichia canis co‐infection in a dog with meningoencephalitis

An 8‐year‐old mixed‐breed dog was presented for acute, progressive weakness and ataxia, inappetence, and weight loss. The patient was mentally normal, but nonambulatory, with a right head tilt, right positional ventral strabismus, and slight head tremors. A neurologic lesion was localized to the cerebellum and right brainstem. Cerebrospinal fluid (CSF) analysis showed a markedly increased protein concentration and mixed pleocytosis, with eosinophil predominance (44%), intracytoplasmic inclusions within eosinophils, consistent with Ehrlichia canis (E canis) morulae, and Toxoplasma gondii (T gondii) or Neospora caninum (N caninum) tachyzoites within eosinophils and monocytes. A serum indirect immunofluorescent antibody test was positive for N caninum (titer 1:12 800) and negative for T gondii. Both blood and CSF PCR results were N caninum‐ and E canis‐positive and T gondii‐ and Anaplasma phagocytophilum‐negative, and blood PCR, but not CSF PCR, was Hepatozoon canis‐positive. The dog was treated for 30 days with clindamycin, sulfamethoxazole‐trimethoprim, doxycycline, prednisone, and cephalosporin, but did not improve neurologically, and was euthanized. Brain histopathology showed moderate multifocal, subacute meningoencephalitis with necrosis and gliosis. The neurologic disease was mostly attributed to central nervous system (CNS) neosporosis, with the possible contribution of ehrlichiosis, which was likely a manifestation of blood‐brain barrier disruption. Hepatozoonosis was probably a result or cause of underlying immunosuppression. To our knowledge, this is the first report of CNSN caninum and E canis co‐infection detected by both CSF PCR and cytology and E canis morulae identified within CSF eosinophils.     

Cultivation and molecular identification of Ehrlichia canis and Ehrlichia chaffeensis from a naturally co-infected dog in Venezuela

Background: Diagnosis of canine ehrlichiosis in Venezuela is normally performed by examination of buffy coat smears (BCS). Characteristic inclusion bodies are frequently observed in leukocytes and platelets from dogs with clinical signs of the disease. Objective: The purpose of this study was to investigate the co-infection of a dog with Ehrlichia canis and E hrlichia chaffeensis using microbiological and molecular techniques. Methods: Primary cultures of monocytes from a dog showing signs of ehrlichiosis were performed. Ehrlichial inclusions in blood cells were demonstrated by BCS and in cultured cell smears with direct immunofluorescence and Dip Quick staining. Nested PCR analysis was performed with DNA from blood samples and cultures, using primers specific for E. canis and E. chaffeensis. The amplified DNA fragments were sequenced to confirm the specificity of the amplifications. Results: The BCS of the naturally infected dog contained intracellular morulae. Ehrlichial inclusions were observed 9 days after inoculation of the primary cultures. After 3 passages with monocytes from a healthy dog, 65% of infected cells, and cells with >60 morulae were observed. A healthy female German Shepherd dog, seronegative for E. canis and E. chaffeensis antigens and without contact to ticks, was inoculated with an infected culture. The animal developed signs of canine monocytic ehrlichiosis and became seropositive. Nested PCR results and sequencing of amplified DNA fragments demonstrated the simultaneous presence of E. canis and E. chaffeensis in both dogs. Conclusions: This is the first report of E. chaffeensis in dogs in South America. This organism was previously identified in dogs by PCR only in the United States.     

Evaluation of cytology in the diagnosis of acute canine monocytic ehrlichiosis (Ehrlichia canis): a comparison between five methods

The purpose of this study was the comparison of the diagnostic sensitivity between buffy coat (BC), peripheral blood (PB), lymph node (LN), bone marrow (BM) and short-term culture (P-D) cytology that has been based on the detection of Ehrlichia canis morulae, in the acute phase of canine monocytic ehrlichiosis (CME). Their cellular localization, total numbers and microscopic differentials were also investigated. The highest sensitivities were achieved after evaluating 1000 oil immersion fields (OIFs) in BC (66%) and an equal number in LN (60.9%) smears, separately or together (74%). The morulae were more often detected into lymphocytes than monocytes. The highest total number of morulae (n=143) were found in P-D smears. Finally, to avoid false positive diagnoses, platelets, lymphocytic azurophilic granules, lymphoglandular bodies and phagocytosed nuclear material should not be confused with the morulae.