Prevalence of Babesia and Ehrlichia in owned dogs with suspected tick-borne infection in Hong Kong, and risk factors associated with Babesia gibsoni.

Babesiosis and ehrlichiosis are the most clinically significant tick-borne infections in dogs. Although epidemiological investigations of these diseases have been performed in some Asian regions, little data is available in Hong Kong, where competent vector tick species are endemic. The objectives of this study were to determine the molecular prevalence of Ehrlichia canis and Babesia species (B. canis, B. gibsoni, B. vogeli) in owned dogs suspected of tick-borne infection in Hong Kong and to identify risk factors associated with B. gibsoni infection. Electronic records from the Veterinary Diagnostic Laboratory of City University of Hong Kong were searched to identify canine blood samples submitted for molecular testing of these pathogens by real time PCR between March 2018 and May 2021. Electronic patient records from the affiliated veterinary hospital were searched to identify a subset of tested dogs to investigate the potential risk factors for B. gibsoni infection using logistic regression models. Among 1508 tested dogs for all four pathogens of interest, Babesia spp. were detected in 435 (28.8%) and E. canis in 112 (7.4%). Babesia gibsoni was detected in 408 dogs while B. vogeli was detected in 27 dogs. Babesia canis was not detected in any dog. Co-infections of different combinations of B. gibsoni, B. vogeli and E. canis were present in 25 dogs. In multivariable logistic regression, mixed breed dogs were more likely to be infected with B. gibsoni than purebreds (P = 0.005), while dogs > 10 years of age were less likely to be infected than younger dogs (P = 0.019). Hematological abnormalities significantly associated with B. gibsoni infection included thrombocytopenia, neutropenia, or pancytopenia. Babesiosis caused by B. gibsoni is a common infection in owned dogs suspected of tick-borne infection in Hong Kong. The risk factors reported should be considered in diagnosing dogs suspected of infection with this agent. Furthermore, consideration for testing for B. gibsoni infection should be given if the results of a complete blood count show thrombocytopenia even in the absence of anemia, neutropenia or pancytopenia.

Clinical and clinicopathological features and outcomes of cats with suspected dietary induced pancytopenia.

BACKGROUND: After a strong epidemiological link to diet was established in an outbreak of pancytopenia in cats in spring 2021 in the United Kingdom, 3 dry diets were recalled. Concentrations of the hemato- and myelotoxic mycotoxins T-2, HT-2 and diacetoxyscirpenol (DAS) greater than the European Commission guidance for dry cat foods were detected in the recalled diets. OBJECTIVES: To describe clinical and clinicopathological findings in cats diagnosed with suspected diet induced pancytopenia. ANIMALS: Fifty cats presenting with pancytopenia after exposure to a recalled diet. METHODS: Multicenter retrospective case series study. Cats with known exposure to 1 of the recalled diets were included if presented with bi- or pancytopenia and underwent bone marrow examination. RESULTS: Case fatality rate was 78%. Bone marrow aspirates and biopsy examination results were available in 23 cats; 19 cats had a bone marrow aspirate, and 8 cats had a biopsy core, available for examination. Bone marrow hypo to aplasia-often affecting all cell lines-was the main feature in all 31 available core specimens. A disproportionately pronounced effect on myeloid and megakaryocytic cells was observed in 19 cats. Myelofibrosis or bone marrow necrosis was not a feature. CONCLUSION AND CLINICAL IMPORTANCE: Mycotoxin induced pancytopenia should be considered as differential diagnosis in otherwise healthy cats presenting with bi- or pancytopenia and bone marrow hypo- to aplasia.

An investigation into an outbreak of pancytopenia in cats in the United Kingdom.

BACKGROUND: In spring 2021 increasing numbers of cats presenting with severe pancytopenia were noted in United Kingdom (UK). OBJECTIVE: To describe process and outcome of the investigation performed into the outbreak of pancytopenia in cats. ANIMALS: Five hundred and eighty client owned cats that presented with severe bi- or pancytopenia of unknown cause. METHODS: Real-time data collection was performed by an online registration forum available to all veterinary surgeons in UK. Data collected included demographics, clinicopathological findings, diagnostic testing, dietary and drug history, outcome and COVID household status. Mycotoxicological feed analysis was performed on feed samples of 3 diets frequently mentioned in the database and 3 control diets. RESULTS: Five hundred and eighty cats presented to 378 veterinary practices were included for analysis. Case fatality rate was 63.3%. Dietary history was available for 544 (93.8%) cats, of which 500 (86%) were fed 1 of 3 diets (which were recalled midinvestigation). 54 (9.3%) cats were not fed a recalled product, with diet information unknown in 26 (4.5%) cats. Analysis of feed samples revealed concentrations of hematotoxic trichothecene T-2/HT-2 mycotoxins greater than recommended by the European Commission in 5/7 recalled diet samples but in none of control diet samples. The trichothecene mycotoxin diacetoxyscirpenol (DAS) was detectable in all recalled diet samples but not in any of control samples. CONCLUSION AND CLINICAL IMPORTANCE: Contaminated-feed induced trichothecene mycotoxicosis should be considered as a differential diagnosis for pancytopenia in cats.

A feline case of multiple myeloma treated with bortezomib.

BACKGROUND: Multiple myeloma (MM) is an uncommon neoplasm in cats. There is no established standard of treatment due to the rare occurrence of this disease in cats. Bortezomib is a proteasome inhibitor that serves as the first-line drug for MM in humans, but its effectiveness currently is unknown in feline MM. We present here the case report of a feline MM that exhibited a favorable response to bortezomib. CASE PRESENTATION: The case was an 11-year-old non-castrated male domestic cat with light-chain MM presenting with clinical symptoms (anorexia, fatigue, and vomiting), mild azotemia, and pancytopenia. The cat failed on melphalan with prednisolone (MP), so bortezomib (Velcade) was initiated on Day 88. A total of 6 cycles of the treatment was performed, with each treatment cycle consisting of twice-weekly subcutaneous administration for 2 weeks followed by a 1-week rest. The dose of bortezomib was 0.7 mg/m2 for first week and 1.0 mg/m2 for second week in the first cycle. A dose of 0.7 mg/m2 was used for subsequent cycles. Prednisolone was used concomitantly in the first 2 cycles. Following treatment with bortezomib, clinical symptoms disappeared and a decrease in serum globulin and recovery of pancytopenia were noted. A monoclonal gammopathy, overproduction of serum immunoglobulin light chain, and Bence-Jones proteinuria that existed at diagnosis were undetectable on Day 123. A monoclonal gammopathy also was not detectable at the end of the bortezomib treatment (Day 213). Anorexia, fatigue, and marked bone marrow toxicity were experienced when bortezomib was administrated at a dose of 1.0 mg/m2, while no recognizable toxicity was observed at a dose of 0.7 mg/m2 throughout the treatment period. The case was placed on follow-up and there was no evidence of relapse as of Day 243. CONCLUSIONS: Bortezomib was effective and durable for the treatment of this case of feline MM after failure with MP. Bortezomib was well-tolerated in this cat at a dose of 0.7 mg/m2, but not at 1.0 mg/m2. Bortezomib appears to be a drug worthy of further study for the treatment of feline MM.

[Occurrence of canine babesiosis in dogs in the Rhine-Main area of Hesse, Germany - a case study of 81 dogs]. / Vorkommen von kaniner Babesiose bei Hunden im Rhein-Main-Gebiet in Hessen ­ eine Fallstudie mit 81 Hunden.

OBJECTIVE: Canine babesiosis, an infectious disease transmitted by Dermacentor reticulatus, is exhibiting growing importance in Germany. The aim of this study was to display the increased incidence of canine babesiosis in the Rhine-Main area in Hesse, with special focus on the accumulation in the district of Groß-Gerau. MATERIAL AND METHODS: The retrospective study included dogs presented to the veterinary hospital between October 2018 and December 2020 and diagnosed with canine babesiosis on the basis of a positive Babesia spp.-PCR. RESULTS: A total of 697 dogs were tested by Babesia spp.-PCR during this time period. Of these, 81 (12 %) were positive.Sequencing was performed in 14 of the 81 dogs (17 %) (B. canis n = 13, B, vulpes n = 1). A simultaneous anaplasmosis infection was detected in 2 dogs. Strikingly, babesiosis cases occurred throughout the year with accumulations in March/April as well as in October.Evaluation of a complete blood cell count revealed pancytopenia in 44 of the 81 animals (54 %). Anemia was present in 66 (82 %), thrombocytopenia in 76 of the 81 patients (94 %). Only 2 of the 81 positive cases showed no hematological changes. Hyperbilirubinemia was found in 66 of 73 measured bilirubin levels (90 %).All animals were treated with two injections of imidocarb-diproprionate (Carbesia®) in 14-day intervals. Follow-up PCR was performed in 37 of the 81 patients (46 %). In the majority of cases (92 %), successful therapy was confirmed by a negative Babesia-PCR. A total of 6 of the 81 patients (7 %) were euthanized during the treatment period. The reasons for euthanasia were progressive renal disease, high-grade intravascular hemolysis necessitating multiple blood transfusions, and development of splenic and renal abscesses. CONCLUSION: In dogs with clinical signs such as apathy, pyrexia and hemoglobinuria, as well as hematologic abnormalities comprising anemia, thrombocytopenia as well as pancytopenia, babesiosis needs to be included in the list of differential diagnoses. Testing should be initiated accordingly regardless of the season, however especially in spring and autumn.

Three cases of alloimmune mediated pancytopenia in calves resembling bovine neonatal pancytopenia.

BACKGROUND: Between 2007 and 2011 several thousands of calves died from bovine neonatal pancytopenia (BNP), a bleeding syndrome triggered by vaccine induced alloantibodies from the dams. Following withdrawal of the involved bovine viral diarrhoea virus (BVDv) vaccine, the incidence of this condition rapidly decreased, with no reported cases in the last 5 years. Here, we report a recent immune-mediated pancytopenia in three calves from two different suckler herds, clinically indistinguishable from BNP. CASE PRESENTATION: Three Belgian Blue suckler calves from two different farms, aged around two weeks, showed multiple bleedings disseminated on the skin and petechiae and ecchymoses on the mucosae. Blood examination confirmed anaemia, leukopenia and thrombocytopenia. BVDv infection was excluded. Despite blood transfusion and cortisone therapy, all three animals died. Necropsy and histology confirmed bone marrow depletion. Binding of IgG from the dams on leukocytes of the calves was demonstrated by flow cytometry. Two calves, originating from the same farm, received colostrum from the same dam. None of the calves were given colostrum replacers or colostrum supplements. No link with the BNP causing BVDv vaccine could be evidenced. However, dams had been vaccinated against bovine herpesvirus 1, parainfluenza-3 virus, bovine respiratory syncytial virus and bluetongue virus serotype 8. CONCLUSIONS: Alloimmune mediated pancytopenia was evidenced in three animals, clinically and pathologically indistinguishable from BNP. Whether this disease is again vaccine mediated remains to be determined.

Nontraumatic hemoabdomen and pancytopenia secondary to myelolipoma in a cat.

OBJECTIVE: (1) To report an unusual etiology for nontraumatic hemoabdomen in cats, and (2) to describe onset and recovery from severe, unexpected pancytopenia seen after surgical removal of a large intra-abdominal myelolipoma. CASE SUMMARY: A 14-year-old neutered male domestic shorthair cat was presented for emergent treatment of suspected nontraumatic hemoabdomen. A hyperechoic mass, with ultrasonographic echogenicity similar to fat, was found in the right cranial abdomen and believed to be associated with the mesentery. Cytological examination of abdominal fluid identified marked extramedullary hematopoiesis within the hemorrhagic effusion. Exploratory laparotomy identified a hepatic mass, which was resected, and revealed to be a hepatic myelolipoma on histopathological examination. The patient's initial recovery was uneventful. However, continued hyporexia resulted in readmission 4 days postoperatively, at which time the patient was found to have a profound, tri-lineage pancytopenia, and cytological evidence indicative of bone marrow recovery. The pancytopenia resolved with continued medical management and supportive care. NEW OR UNIQUE INFORMATION PROVIDED: Ruptured myelolipoma is not a commonly considered differential for nontraumatic hemoabdomen in cats. Furthermore, severe pancytopenia is unexpected following surgical resection of a myelolipoma. This case provides a unique clinical presentation of both nontraumatic hemoabdomen and bone marrow recovery.

Outcome of dogs with bone marrow suppression secondary to Sertoli cell tumour.

Sertoli cell tumours are one of the most common canine testicular neoplasia. These tumours are significantly more likely to arise in cryptorchid dogs and are often functional, oestrogen-secreting tumours which can lead to fatal myelotoxicity. The goal of this study was to describe the outcome of dogs with oestrogen-induced bone marrow suppression secondary to Sertoli cell tumours in seven client-owned dogs. Medical records from April 1, 2011 through April 1, 2021 were reviewed to identify dogs that underwent surgical management of a Sertoli cell tumour with documented bone marrow suppression. Overall, 5/7 dogs required transfusion of blood products peri-operatively. Cases 1 and 6 received a transfusion of packed red blood cells (RBC) prior to surgery and case 5 required a transfusion of whole blood. Case 1 also required a transfusion of platelets before surgery. Post-operatively, cases 1 and 2 received packed RBC's and case 6 received two transfusions of whole blood. Case 3 required transfusions of both fresh frozen plasma and platelets post-operatively. All dogs survived to discharge and 6/7 dogs had documented improvement in haematopoietic values. Two dogs remained chronically thrombocytopenic. The median hospital stay was 4 days. One dog died within 4 weeks of surgery from worsening pancytopenia. Survival for greater than 1 year was documented in 4/7 dogs, and one dog was lost to follow-up 4 months post-operatively. One dog remained severely pancytopenic 4 weeks post-operatively and received oral lithium treatment. Improvements in all blood cell lines were observed within the 4 weeks and resolution of pancytopenia within 6 weeks. Historically, the prognosis for dogs with bone marrow suppression secondary to Sertoli cell tumours was guarded to poor. This report documented improved outcomes for dogs that underwent surgery, including one dog that received lithium chloride as treatment for Sertoli cell tumour-induced bone marrow suppression.

Pancytopenia secondary to suspected idiosyncratic phenobarbital reaction in a dog.

A 4-year-old neutered male St. Bernard-mastiff crossbred dog showed clinical signs of lethargy and anorexia after being administered phenobarbital for the treatment of idiosyncratic seizures. A complete blood (cell) count revealed pancytopenia. Auto-agglutination and Coombs tests were negative suggesting that an immunemediated cause was unlikely; therefore, an idiosyncratic reaction to phenobarbital was suspected. Supportive care and control of seizures with zonisamide was initiated and clinical signs improved. Blood values were monitored closely and returned to normal after 3 wk.

Pancytopénie secondaire à une suspicion de réaction idiosyncratique au phénobarbital chez un chien. Un chien mâle castré de 4 ans croisé St-Bernard-mastiff a montré des signes cliniques de léthargie et d'anorexie après avoir reçu du phénobarbital pour le traitement de crises idiosyncratiques. Une numération cellulaire sanguine complète a révélé une pancytopénie. Les tests d'auto-agglutination et de Coombs étaient négatifs, suggérant qu'une cause à médiation immunitaire était peu probable; par conséquent, une réaction idiosyncratique au phénobarbital a été suspectée. Des soins de soutien et la maitrise des crises avec le zonisamide ont été initiés et les signes cliniques se sont améliorés. Les valeurs sanguines ont été étroitement surveillées et sont revenues à la normale après 3 semaines.(Traduit par Dr Serge Messier).

[Acquired transient Fanconi syndrome after feeding jerky treats in dogs - A case series]. / Erworbenes transientes Fanconi-Syndrom nach Fütterung von Trockenfleisch als Leckerchen beim Hund.

Between April 2018 and August 2019, 6 dogs with laboratory diagnostic evidence of Fanconi syndrome were presented to the Tierklinik Hofheim. The presumptive diagnosis was confirmed via urine amino acid analysis in all dogs. In 5 of the 6 dogs an alimentary origin was suspected, in 3 dogs the course of the disease could be followed. Supportive therapeutic measures and elimination of jerky treats from the dogs' diet improved the clinical symptoms in all dogs with known follow-up. This is the first case series of dogs with alimentary acquired Fanconi syndrome in Germany. The frequency of occurrence of the disease in that short period of time in only one small animal clinic suggests a significantly higher incidence than currently assumed.

Persistent infection and pancytopenia associated with ferret systemic coronaviral disease in a domestic ferret.

Ferret systemic coronaviral disease (FSCD) is a well-established cause of mortality in domestic ferrets. We describe herein novel findings in a case of FSCD that was diagnosed and medically managed following virus detection by immunohistochemical (IHC) staining of surgical biopsy samples. Hematologic changes in this ferret suggested spread of the virus to the bone marrow, which was confirmed by IHC staining of a postmortem sample. Genotyping of the virus indicated that the virus grouped with alphacoronaviruses and was most closely related to ferret enteric coronavirus (FRECV) MSU-2. Our clinical case demonstrates that a FRECV MSU-2-like ferret coronavirus associated previously with the enteric pathotype may cause systemic disease, including bone marrow involvement causing persistent pancytopenia.

Spatial distribution and incidence of bovine neonatal pancytopenia in Bavaria, Germany.

BACKGROUND: Bovine neonatal pancytopenia (BNP) is a haemorrhagic disease of neonatal calves. BNP was first described in Germany in 2009, later on also in other European countries, and in New Zealand in 2011. The disease is characterised by spontaneous bleeding, pancytopaenia in the bone marrow, and a high case fatality ratio. The causal role of a specific bovine viral diarrhoea virus (BVDV) vaccine (PregSure®BVD, then Pfizer Animal Health, now Zoetis, Berlin, Germany) has been established over the last years, causing the production of alloantibodies in some vaccinated cattle, which in the case of pregnant cattle, are transferred to the newborn calf via the colostrum. However, striking regional differences in the incidence of the disease were observed within Germany and other countries, but as the disease was not notifiable, no representative data on the spatial distribution are available. In this study, we address the spatial distribution and incidence of BNP using the results of two representative surveys amongst cattle practitioners in Bavaria, Germany. The surveys, asking about the occurrence of BNP, were conducted in 2009 and 2010. Answers were analysed spatially by testing for clusters using space-time models. Practitioners were also asked how many cows they serve in their practice and this number was used to estimate the incidence of BNP. Furthermore, in the survey of 2010, practitioners were also asked about usage of vaccine against BVDV. RESULTS: From the results of the surveys, three clusters were identified in Bavaria. These clusters also coincided with the usage of the specific BVDV vaccine as indicated by the veterinary practices. Furthermore, the representative surveys allow the estimation of the incidence of BNP to be in the order of 4 cases per 10,000 calves at risk. CONCLUSIONS: The study is the only representative survey conducted on BNP. Despite the fact that BNP is a non-infectious disease, regional clusters were identified.

Eltrombopag treatment of a dog with idiopathic aplastic pancytopenia.

Idiopathic aplastic pancytopenia is an uncommon disease in dogs which results in pancytopenia and for which an immune-mediated etiology is suspected. A small number of affected dogs reported in the veterinary literature have responded to immunosuppressive medication but the prognosis generally is considered poor with a reported mortality rate of 80%. Reported response rates to immunosuppression alone in affected people are low with overall and complete responses of 65 and 10%, respectively. With the addition of eltrombopag, an orally available thrombopoietin receptor agonist, reported overall and complete response rates in people increase to 94 and 58%, respectively. Herein, we report the use of eltrombopag in a dog with idiopathic aplastic pancytopenia. Eltrombopag was started after no response was seen to treatment with prednisolone and cyclosporine. Complete remission was achieved after the addition of eltrombopag and was sustained after stopping the medication.

An update on the treatment of canine monocytic ehrlichiosis (Ehrlichia canis).

Canine monocytic ehrlichiosis (CME), caused by Ehrlichia canis, a gram-negative, obligate intracellular bacterium, is a tick-borne disease of worldwide distribution. Experimentally, the course of E. canis infection can be sequentially divided into acute, subclinical and chronic phases, although distinction of these phases is challenging in the clinical setting. Spontaneous clinical recovery of acutely infected dogs is common; however, dogs at this stage require medical treatment in order to hasten their clinical recovery, and to prevent clinical exacerbation or death. An unpredictable proportion of subclinically infected dogs will eventually develop the chronic, severe form of ehrlichiosis, characterized by aplastic pancytopenia and high mortality. The aims of antimicrobial treatment in CME include the achievement of clinical remission, resolution of the clinicopathologic abnormalities, and eradication of the infection, although the latter is not always feasible or diagnostically confirmable. Treatment of dogs with aplastic pancytopenia should be undertaken with the clear understanding that medical management will require long-term care, will be expensive, and may eventually prove ineffective. This manuscript reviews the current state of knowledge regarding treatment of ehrlichiosis, caused by E. canis infection in dogs, provides expert opinion guidelines for the management of the CME-associated aplastic pancytopenia, and outlines methods for evaluation of treatment outcomes.

A Functionally Different Immune Phenotype in Cattle Is Associated With Higher Mastitis Incidence.

A novel vaccine against bovine viral diarrhea (BVD) induced pathogenic antibody production in 5-10% of BVD-vaccinated cows. Transfer of these antibodies via colostrum caused Bovine neonatal pancytopenia (BNP) in calves, with a lethality rate of 90%. The exact immunological mechanisms behind the onset of BNP are not fully understood to date. To gain further insight into these mechanisms, we analyzed the immune proteome from alloreactive antibody producers (BNP cows) and non-responders. After in vitro stimulation of peripheral blood derived lymphocytes (PBL), we detected distinctly deviant expression levels of several master regulators of immune responses in BNP cells, pointing to a changed immune phenotype with severe dysregulation of immune response in BNP cows. Interestingly, we also found this response pattern in 22% of non-BVD-vaccinated cows, indicating a genetic predisposition of this immune deviant (ID) phenotype in cattle. We additionally analyzed the functional correlation of the ID phenotype with 10 health parameters and 6 diseases in a retrospective study over 38 months. The significantly increased prevalence of mastitis among ID cows emphasizes the clinical relevance of this deviant immune response and its potential impact on the ability to fight infections.

Bovine Neonatal Pancytopenia-Associated Alloantibodies Recognize Individual Bovine Leukocyte Antigen 1 Alleles.

Bovine neonatal pancytopenia (BNP) was a vaccine-induced alloimmune disease observed in young calves and characterized by hemorrhages, pancytopenia, and severe destruction of the hematopoietic tissues. BNP was induced by alloreactive maternal antibodies present in the colostrum of certain cows vaccinated with a highly adjuvanted vaccine against bovine viral diarrhea. Bioprocess impurities, originating from the production cell line of the vaccine, are likely to have induced these alloreactive antibodies. One prominent alloantigen recognized by vaccine-induced alloantibodies is highly polymorphic bovine major histocompatibility complex class I antigen (bovine leukocyte antigen 1-BoLA I). Aim of this study was to define the fine specificity of BNP-associated anti-BoLA I alloantibodies. In total, eight different BoLA I alleles from the production cell line were identified. All genes were cloned and recombinantly expressed in murine cell lines. Using these cells in a flow cytometric assay, the presence of BoLA I specific alloantibodies in BNP dam sera was proven. Three BoLA I variants were identified that accounted for the majority of vaccine-induced BoLA I reactivity. By comparing the sequence of immunogenic to non-immunogenic BoLA I variants probable minimal epitopes on BoLA I were identified. In general, dams of BNP calves displayed high levels of BoLA I reactive alloantibodies, while vaccinated cows delivering healthy calves had significantly lower alloantibody titers. We identified a subgroup of vaccinated cows with healthy calves displaying very high alloantibody titers. Between these cows and BNP dams no principle difference in the BoLA I reactivity pattern was observed. However, with a limited set of dam-calf pairs it could be demonstrated that serum from these cows did not bind to BoLA I expressing leukocytes of their offspring. By contrast, when testing cells from surviving BNP calves with the corresponding dam's serum there was significant binding. We therefore conclude that predominantly highly alloreactive cows are at risk to induce BNP and it depends on the paternally inherited BoLA I whether or not the calf develops BNP.

High-Dose Filgrastim Treatment of Nonregenerative Pancytopenia Associated With Chronic Canine Ehrlichiosis.

OBJECTIVE: To report the management and outcome of a dog with canine monocytic ehrlichiosis and nonregenerative pancytopenia, with high doses of filgrastim. CASE DESCRIPTION: An 8-year-old male, mixed-breed dog, weighing 5.6kg, presented with a 1-month history of hyporexia, adynamia, and a weight loss of approximately 1kg. The general condition of the dog was observed to be poor as follows: lethargy, tachycardia, marked pallor of the mucous membranes, petechiae on the abdomen, hepatosplenomegaly, and cervical lymphadenopathy. A complete blood count analysis revealed severe leukopenia, thrombocytopenia, and anemia. A direct immunofluorescence assay using anti-Ehrlichia canis-immunoglobin G (1:400) yielded positive result. The dog was diagnosed with nonregenerative pancytopenia associated with canine monocytic ehrlichiosis. The dog presented poor prognostic signs (neutropenia, thrombocytopenia, and severe anemia). The dog was treated with antibiotics and a short course of high-dose filgrastim (50µg/kg, SC, q 48h for 4 days) to stimulate bone marrow response, prednisone to decrease peripheral platelet destruction, and an iron supplement to compensate for the iron deficiency in the bone deposits. Although temporary side effects associated with filgrastim use, such as bone pain, bleeding, and the worsening of thrombocytopenia, were observed, the treatment improved the clinical course and the cell counts in less than a month. CLINICAL RELEVANCE: The treatment protocol used in this case might be an alternative for treating cases of severe myelosuppression. This treatment plan can substantially change the clinical course of the disease for the better, compared to conventional treatment.