Lung pathology of natural Babesia rossi infection in dogs.

A proportion of Babesia rossi infections in dogs are classified as complicated and one of the most lethal complications is acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Most dogs that die succumb within 24 hours of presentation. The pulmonary pathology caused by B. rossi in dogs has not been described. The aim of this study was to provide a thorough macroscopic, histological and immunohistochemical description of the lung changes seen in dogs naturally infected with B. rossi that succumbed to the infection. Death was invariably accompanied by alveolar oedema. Histopathology showed acute interstitial pneumonia characterised by alveolar oedema and haemorrhages, with increased numbers of mononuclear leucocytes in alveolar walls and lumens. Intra-alveolar polymerised fibrin aggregates were observed in just over half the infected cases. Immunohistochemistry showed increased numbers of MAC387- and CD204-reactive monocyte-macrophages in alveolar walls and lumens, and increased CD3-reactive T-lymphocytes in alveolar walls, compared with controls. These histological features overlap to some extent (but far from perfectly) with the histological pattern of lung injury referred to as the exudative stage of diffuse alveolar damage (DAD) as is quite commonly reported in ALI/ARDS.

Serial changes in the concentrations of cortisol and thyroid hormones in Beagle dogs infected with Babesia rossi.

An experimental infection using Babesia (B.) rossi was performed in healthy male Beagle dogs to assess the changes in endocrine variables during disease. Two dogs were infected with a low dose (LD) of parasite inoculum (104 parasites) and three dogs were infected with a high dose (HD) (108 parasites). Basal serum cortisol, thyroxine (T4), and thyrotropin (TSH) concentrations were measured every second day. Samples were analyzed using a solid- phase, competitive chemiluminescent enzyme immunoassay (Immulyte® 2000, Siemens). Variables were compared between groups and timepoints using linear mixed models. In both groups, the median cortisol concentration increased, whilst the median T4 concentration decreased after infection, with a return towards baseline concentration post treatment. The highest cortisol and the lowest T4 concentrations were reached at 96 h and 108 h post infection, respectively, in the HD group and slightly later at 108 and 144 h post-infection, respectively, in the LD group. A higher cortisol concentration with a more rapid increase, and a lower T4 concentration with a more rapid decline, were associated with disease severity and a higher dose of parasite inoculum. The TSH concentration remained within the reference interval throughout the study period. This study illustrated the temporal changes in endocrine parameters during experimental B. rossi infection and demonstrated that cortisol and T4 tracked the severity of disease, albeit in opposite directions.

The clinical presentation and management of a naturally occuring Bluetongue virus infection in a pregnant Rottweiler dog.

Few reports of clinical Bluetongue virus (BTV) infections have been described in dogs. Most cases were linked to inoculation with a BTV-contaminated canine modified live vaccine. In dogs, cases have only been described in pregnant females with clinical signs of fever and abortion followed by severe dyspnoea and death. A pregnant Rottweiler dog was presented with a three-day history of progressive lethargy and anorexia. The patient was a guard dog living in an enclosure where sheep were kept at night. High mortalities had been experienced in the sheep but had not been investigated. On presentation, the major clinical findings were dyspnoea and hypoxia. Clinicopathological tests showed hypoxia and systemic inflammation. Radiological findings were consistent with non-cardiogenic pulmonary oedema. The patient was treated symptomatically and recovered but did not retain the pregnancy. Bluetongue virus was identified in the patient's blood using BTV RT-PCR (Ct value 24.7). At a follow-up farm visit, an ongoing BTV outbreak in the sheep was diagnosed with affected sheep testing positive for BTV on RT-PCR. This report describes the clinical presentation, diagnostic investigations and successful treatment of a dog with BTV infection. This is the first case report of a naturally occurring clinical BTV infection in a dog. Possible routes of infection were direct contact, midgeborne, or ingestion of infected afterbirth or abortus from sheep.

Prevalence of methicillin resistance in Staphylococcus pseudintermedius isolates from dogs with skin and ear infections in South Africa.

ABSTRACT: Staphylococcus pseudintermedius (SP) is an important opportunistic pathogen, frequently associated with pyoderma and otitis in dogs. The emergence and rapid expansion of methicillin-resistant Staphylococcus pseudintermedius (MRSP) is problematic due to multidrug resistance and reduced treatment options. The aim of this study was to determine i) the prevalence of MRSP in dogs with pyoderma or otitis externa, ii) the antimicrobial resistance patterns of MRSP from South African isolates, and iii) the risk factors for MRSP-associated pyoderma or otitis externa in dogs in South Africa (RSA). Sixty-eight presumptive clinical SP isolates (collected from 65 dogs) from five geographically dispersed laboratories in RSA were collected over 2 years. Possible MRSP isolates were flagged when resistance to oxacillin was observed. Thereafter, all isolates were confirmed as SP by polymerase chain reaction (PCR) and further genotyped for the mecA gene. Fifty-seven of 68 isolates were confirmed to be SP (83.8%), while 49/57 (85.9%) carried mecA. Our findings showed that preliminary phenotypic methods supplemented by genotypic methods increased the accuracy of correctly identifying SP. All isolates were resistant to at least one antimicrobial drug. There was a high incidence of amoxicillin (70.1%) and enrofloxacin (65%) resistance. Important risk factors for mecA positive carriage were previous hospital admission, pruritus, and previous antibacterial failure. This study demonstrates a high prevalence of mecA positive carriage (85.9% of samples) in MRSP pyoderma and otitis in dogs in RSA. There is an urgent need for better laboratory diagnosis of MRSP and surveillance of dogs presenting with pyoderma and otitis in South Africa.

Kinetics of the inflammatory response during experimental Babesia rossi infection of beagle dogs.

Babesia rossi causes severe morbidity and mortality in dogs in sub-Saharan Africa, and the complications associated with this disease are likely caused by an unfocused, excessive inflammatory response. During this experimental B. rossi study we investigated inflammatory marker and cytokine kinetics during infection and after treatment. We aimed to determine whether infectious dose and treatment would influence the progression of the inflammatory response and clinical disease. Six healthy male beagle dogs formed the study population, one was used to raise the infectious inoculum, three were administered a high B. rossi infectious dose (HD group) and two a low infectious dose (LD group). Clinical examination, complete blood count (CBC) and C-reactive protein (CRP) were determined daily. Cytokines were quantified on stored plasma collected during the study, using a canine specific cytokine magnetic bead panel (Milliplex©). The experiment was terminated and treatment administered when predetermined experimental or humane endpoints were reached. Parasitemia occurred on day 1 and 3 in the HD and LD groups respectively. The rate of increase in parasitemia in the HD group was significantly faster than that seen in the LD group. Significant differences were found in heart rate, blood pressure, interferon gamma (INFγ), keratinocyte chemoattractant (KC), INFγ-induced protein 10 (IP10), granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP1), tumor necrosis factor alpha (TNFα), interleukin 2 (IL-2), IL-6, IL-7, IL-8, IL-10 IL-15, IL-18, CRP, neutrophils and monocytes between groups at multiple time points during the course of the infection. Our findings suggest that the initiation of inflammation occurs before the onset of clinical disease in B. rossi infection and infectious dose influences the onset of the inflammatory response. Treatment enhances the inflammatory response in the immediate post-treatment period which may contribute to disease associated complications. Finally, we found that there is an imbalance in pro/anti-inflammatory cytokine concentrations during infection which may promote parasite replication.

Evaluation of acute kidney injury in dogs with complicated or uncomplicated Babesia rossi infection.

Dogs with babesiosis can present with multiple complications, including acute kidney injury (AKI). The objective of this study was to characterize AKI in dogs with babesiosis caused by Babesia rossi at presentation and after treatment. Thirty-five client-owned dogs with B. rossi infection and 10 control dogs were included in this prospective observational study. Blood and urine were collected in Babesia-infected dogs at presentation (T0, n = 35), after 24 h (T24h, n = 11), and after 1 month (T1m, n = 9). The following urinary kidney injury biomarkers were assessed: urinary protein to creatinine ratio (UPC), urinary glomerular injury biomarkers (immunoglobulin G (uIgG) and C-reactive protein (uCRP)), and urinary tubular injury biomarkers (retinol-binding protein (uRBP) and neutrophil gelatinase-associated lipocalin (uNGAL)). Serum functional renal biomarkers were creatinine (sCr) and symmetric dimethylarginine (sSDMA). Post-mortem kidney biopsies were analyzed by light and transmission electron microscopy. At T0, all kidney injury biomarkers were significantly higher in Babesia-infected dogs compared to healthy controls (P < 0.001), while functional renal biomarkers were not significantly different (P > 0.05). At T24h, all urinary tubular injury biomarkers and UPC decreased significantly (P < 0.01), while glomerular injury biomarkers did not (P = 0.084). At T1m, all urinary kidney injury biomarkers decreased to values not significantly different from healthy controls (P > 0.5). Significant changes in functional renal biomarkers were not seen after treatment (P > 0.05). Dogs with complicated babesiosis had significantly higher glomerular injury biomarkers, UPC, and sSDMA compared to uncomplicated cases (P < 0.05), while all tubular injury biomarkers and sCr were not significantly different (P > 0.1). Dogs with babesiosis caused by B. rossi showed transient kidney injury, which was detected by all kidney injury biomarkers, but remained undetected by functional biomarkers. All infected dogs, irrespective of disease severity, suffered comparable kidney injury based on tubular injury biomarker concentrations, while loss of function was seen more often in dogs with complicated babesiosis based on sSDMA results.

Long-term follow-up of owned, free-roaming dogs in South Africa naturally exposed to Babesia rossi.

Babesia rossi is an important, tick-borne intraerythrocytic protozoan parasite; however, its natural history and epidemiology is poorly understood. Babesia rossi is the most virulent Babesia sp. in domestic dogs and is generally considered to cause severe babesiosis, which is fatal if left untreated. However, subclinical infections and mild disease from B. rossi have been reported, although the clinical progression of these cases was not reported. Therefore, to better understand B. rossi under field conditions, we evaluated its clinical progression and seroprevalence in an owned, free-roaming dog population in Zenzele, South Africa, where the parasite is endemic and prevention is not routine. The entire dog population in Zenzele was monitored intensively at the individual level from March 2008 until April 2014, primarily for a longitudinal study on rabies control. Subsequent evaluation of B. rossi comprised analyses of clinical and laboratory data collected from the Zenzele dog population during the 6 year study period. A substantial proportion (31% (n = 34)) of 109 dogs (randomly selected from every available dog in February/March 2010 older than ~6-8 weeks (n = 246)) tested by Indirect Fluorescent Antibody Test had seroconverted strongly to B. rossi. All 34 dogs were generally consistently healthy adults, determined from regular clinical examinations between March 2008 and April 2014. Blood smear examinations at multiple time points between July 2009 and February 2011 were also undertaken for almost all of these (34) seropositive dogs and all those tested were consistently negative for Babesia spp. Subclinical infections and mild disease were also the main findings for a separate group of 18 dogs positive for Babesia spp. on blood smear examination and confirmed to be infected with B. rossi by Polymerase Chain Reaction - Reverse Line Blot. Almost all of these dogs were positive at only one time point from repeat blood smear examinations between July 2009 and February 2011. We suggest that these observations are consistent with immunity acquired from repeated, low-level exposure to the parasite, generating transient subclinical infections or mild disease. Should this be the case, the use of tick control, particularly in adult dogs in free-roaming populations in B. rossi endemic regions, should be carefully considered.

Renal azotemia and associated clinical and laboratory findings in dogs with Babesia rossi infection.

The occurrence of acute kidney injury in canine babesiosis is not well documented. Furthermore, interpretation of urine specific gravity (USG) to assess renal concentrating ability is hampered by the frequent presence of hemoglobinuria in this disease. This cross-sectional study aimed to test the hypothesis that renal azotemia (RA) is underdiagnosed according to current canine babesiosis literature by determining its occurrence at presentation, using urine osmolality instead of USG to measure urinary concentration. The second objective was to examine potential associations between the presence of RA and selected clinical and laboratory variables at presentation. Medical records available from 3 previously performed prospective data collections were reviewed retrospectively. Client-owned dogs that were diagnosed with babesiosis caused by Babesia rossi, were included if a complete blood count, biochemistry profile, and urinalysis was performed at admission. Urine osmolality was measured to identify dogs with RA. Differences between dogs with RA and dogs without RA were assessed by nonparametric statistics. One hundred and fifty-two dogs were included, of which 26 (17%) were azotemic at admission. The occurrence of RA was 14% (21/152), hence 81% (21/26) of all azotemic dogs were diagnosed with RA. In contrast, when diagnosis of RA was based on an admission USG < 1.030, only 23% (6/26) of the azotemic dogs would have been considered to have RA. Several signalment and clinicopathological findings were found to be associated with the presence of RA, including older age, and the presence of collapse, hypoglycemia, hyperphosphatemia, cerebral babesiosis, and acute respiratory distress syndrome. Lastly, survival at discharge was significantly lower in dogs diagnosed with RA at presentation. Our results clarified that RA is more common than previously reported in B. rossi. This study also demonstrated that USG determination is not a reliable method to evaluate renal concentrating ability in azotemic dogs with babesiosis. Thus, if available, urine osmolality should be part of the diagnostic work-up of dogs infected with B. rossi to avoid misclassification of dogs with RA as having prerenal azotemia. If urine osmolality cannot be measured, clinicians should realize that most azotemic dogs with B. rossi infection have RA.

Biomarkers in canine parvovirus enteritis.

Canine parvovirus (CPV) enteritis has, since its emergence in 1978, remained a common and important cause of morbidity and mortality in young dogs. The continued incidence of parvoviral enteritis is partly due to the virus' capability to evolve into more virulent and resistant variants with significant local gastrointestinal and systemic inflammatory sequelae. This paper reviews current knowledge on historical-, signalment-, and clinical factors as well as several haematological-, biochemical- and endocrine parameters that can be used as diagnostic and prognostic biomarkers in CPV enteritis. These factors include season of presentation, purebred nature, bodyweight, vomiting, leukopaenia, lymphopaenia, thrombocytopaenia, hypercoagulability, hypercortisolaemia, hypothyroxinaemia, hypoalbuminaemia, elevated C-reactive protein and tumour necrosis factor, hypocholesterolaemia and hypocitrullinaemia. Factors contributing to the manifestations of CPV infection are multiple with elements of host, pathogen, secondary infections, underlying stressors and environment affecting severity and outcome. The availability of several prognosticators has made identification of patients at high risk of death and their subsequent targeted management more rewarding.

The utility of uric acid assay in dogs as an indicator of functional hepatic mass.

Uric acid was used as a test for liver disease before the advent of enzymology. Three old studies criticised uric acid as a test of liver function. Uric acid, as an end-product of purine metabolism in the liver, deserved re-evaluation as a liver function test. Serum totalbile acids are widely accepted as the most reliable liver function test. This study compared the ability of serum uric acid concentration to assess liver function with that of serum pre-prandial bile acids in dogs. In addition, due to the renal excretion of uric acid the 2 assays were also compared in a renal disease group. Using a control group of healthy dogs, a group of dogs with congenital vascular liver disease, a group of dogs with non-vascular parenchymal liver diseases and a renal disease group, the ability of uric acid and pre-prandial bile acids was compared to detect reduced functional hepatic mass overall and in the vascular or parenchymal liver disease groups separately. Sensitivities, specificities and predictive value parameters were calculated for each test. The medians of uric acid concentration did not differ significantly between any of the groups, whereas pre-prandial bile acids medians were significantly higher in the liver disease groups compared with the normal and renal disease group of dogs. The sensitivity of uric acid in detecting liver disease overall was 65% while the specificity of uric acid in detecting liver disease overall was 59%. The sensitivity and specificity of uric acid in detecting congenital vascular liver disease was 68% and 59%, respectively. The sensitivity and specificity of uric acid in detecting parenchymal liver disease was 63% and 60%, respectively. The overall positive and negative predictive values for uric acid in detecting liver disease were poor and the data in this study indicated uric acid to be an unreliable test of liver function. In dogs suffering from renal compromise serum uric acid concentrations may increase into the abnormal range due to its renal route of excretion.

Serial haematology results in transfused and non-transfused dogs naturally infected with Babesia rossi.

This prospective longitudinal study investigated the progression of haematological changes in 32 transfused and 54 non-transfused dogs naturally infected with Babesia rossi over the 1st 6 days following diagnosis and treatment. The effect of patient age on the results of complete blood counts was determined. Haematology data were analysed at presentation and at 24 hours, 3 days and 6 days after presentation. Dogs were treated with diminazene aceturate at diagnosis and a blood transfusion was given if deemed clinically required. Mildly to moderately regenerative normocytic normochromic anaemia was observed in all dogs throughout the study period. Transfused dogs more often had an inflammatory leukogram at presentation and at 24 hours, than dogs that were not transfused. In dogs with a left shift, a concurrent normal or decreased segmented neutrophil count was found more commonly than neutrophilia. Severe thrombocytopenia that resolved within a week was common. Blood transfusion alleviated the anaemia, but had no significant effect on white blood cell or platelet responses. Blood cell responses were not significantly influenced by age. In conclusion, the red blood cell and white blood cell responses were less than expected in dogs with babesiosis, given the degree of anaemia and inflammation present. The magnitude of thrombocytopenia and rapid return of the platelet count to normal suggested a possible immune-mediated mechanism for the thrombocytopenia.

An evaluation of changes over time in serum creatine kinase activity and C-reactive protein concentration in dogs undergoing hemilaminectomy or ovariohysterectomy.

The extent of trauma in a patient can be difficult for a clinician to quantify. A prospective study was performed on 2 groups of dogs undergoing either ovariohysterectomy or hemilaminectomy. The serum activity of creatine kinase and serum concentration of C-reactive protein were evaluated preoperatively and then at 4, 6, 8, 12, 24 and 48 hours postoperatively in both groups. The results were compared statistically both within and between the 2 groups. A wide range of results was found at each time point for both analytes although there were no significant differences for either analyte between the 2 surgical groups preoperatively. Thereafter there were significant differences in creatine kinase activity levels between the 2 groups. C-reactive protein concentration results were very similar in the 2 groups with no statistical difference at any time point. The results of this study suggest that the evaluation of CK and CRP at any one time point in a traumatised animal is of limited value. However, the evaluation of the trend of these 2 analytes, even over a relatively short time period, may allow for useful prognostication in clinical cases.

Preliminary evaluation of the BrEMA1 gene as a tool for associating babesia rossi genotypes and clinical manifestation of canine Babesiosis.

Babesia rossi, an intraerythrocytic protozoan, causes a severe, often life-threatening disease of domestic dogs. Dogs treated early for B. rossi infection usually recover from the disease, but dogs left untreated or treated at a later stage of infection seldom survive. Dogs infected with B. rossi have varied clinical manifestations that can be categorized as uncomplicated (with a good prognosis) or complicated (with a poor prognosis). One hundred twenty-one blood samples were collected from dogs presented to the Onderstepoort Veterinary Academic Hospital and diagnosed with babesiosis by the use of a thin blood smear. An additional 20 samples were obtained from Babesia-infected dogs from private clinics around the Onderstepoort, Johannesburg, Durban, White River, and Cape Town areas. The samples were screened by PCR targeting the Babesia rossi erythrocyte membrane antigen gene (BrEMA1) and by sequencing of the polymorphic region (i.e., region with a variable number of hexapeptide repeats). Analysis of PCR products revealed 11 different gene profiles, visualized by gel electrophoresis. Twelve distinct BrEMA1 genotypes were identified by sequencing, but the numbers of hexapeptide repeats varied from 6 to 31 (classified as genotype6 to genotype31). The genotypes were retrospectively compared to the clinical case data. The most frequently encountered B. rossi parasites were those attributed to genotype19 (36.2%), genotype28 and genotype29 (20.6% each), and genotype11 (12.7%). These genotypes were also the ones associated with the poorest prognosis. This preliminary finding suggests clinically important differences between the various B. rossi genotypes identified.

The scintigraphic evaluation of the pulmonary perfusion pattern of dogs hospitalised with babesiosis.

The possibility of coagulopathy in Babesia canis rossi infections in the canine patient has been suggested in the literature, but minimal work has been done to evaluate the clinicopathological nature of it in further detail. Pulmonary thromboembolism (PTE) has not yet been implicated in canine babesiosis (CB), but may also be one of the causes of the sudden dyspnoea and tachypnoea that are frequently seen in complicated CB patients. The objective of this study was to prospectively evaluate the scintigraphic pulmonary perfusion pattern in hospitalised dogs with babesiosis in an attempt to ascertain whether a scintigraphic pattern consistent with clinically relevant PTE does indeed occur in these patients. The study consisted of a normal control group of 9 mature healthy Beagle dogs (group 1) and a Babesia group with 14 dogs of a variety of breeds that were naturally infected with Babesia (group 2). Pulmonary perfusion scintigraphy was performed after making thoracic radiographs and performing a blood gas analysis in both groups. The scintigraphic images were visually inspected for changes suggestive of PTE, but not a single dog in group 2 had pleural-based, wedge-shaped perfusion defects which would have resulted in a high probability for clinically relevant PTE. The scintigraphic pulmonary perfusion pattern demonstrated was not significantly different between the 2 groups (P = 1.00).

Detection of a Theileria species in dogs in South Africa.

A Theileria species was detected by PCR in blood samples collected from dogs in the Pietermaritzburg area and was also found in dogs presented at the Outpatients Clinic of the Onderstepoort Veterinary Academic Hospital (OVAH), in the Pretoria area, South Africa. In the Pietermaritzburg area, 79 of the 192 samples were positive, while 3 out of 1137 of the Onderstepoort samples were positive. Three positive samples from Pietermaritzburg were co-infected with Ehrlichia canis. PCR positive samples were further analysed by the Reverse Line Blot (RLB) and sequence analysis. Phylogenetic analysis of the 18S rRNA full-length gene sequences of one sample (VT12) from Pietermaritzburg and two samples from OVAH (BC281 and BC295) revealed a close relationship with sequences of Theileria species (sable). Clinical signs of the dogs that were examined at Pietermaritzburg and OVAH included an immune-mediated condition with severe thrombocytopenia. These findings identify a Theileria sp. in dogs for the first time in South Africa and add yet another microorganism to the growing list of haemoprotozoan parasites infecting dogs worldwide. The clinical significance of this infection in dogs is poorly resolved.

Prognostic usefulness of blood leukocyte changes in canine parvoviral enteritis.

BACKGROUND: Despite treatment, many dogs still die of complications related to canine parvoviral (CPV) enteritis. Effective prognostication would be beneficial in managing this disease. HYPOTHESIS: We hypothesize that the occurrence of leukocytopenias at admission and at 24 and 48 hours after admission, and changes in absolute leukocyte counts over time, could be used to predict outcome. ANIMALS: Sixty-two puppies with confirmed CPV. METHODS: A prospective study was performed. CBC was performed daily until discharge or death (in which case a postmortem examination was performed). RESULTS: Of the nonsurvivors (10/62; 16%), 9 died because of complications of the disease and 1 was euthanized because of a poor prognosis. There was a statistical significant difference in the occurrence of leukocytopenias between groups at 24 and 48 hours postadmission. The survivors showed a significant increase over time in certain leukocyte types (specifically lymphocytes) compared with values at admission. The positive predictive value for survivors was high. Nonsurvivors had marked thymic and lymphoid atrophy and marked bone marrow hypocellularity. CONCLUSION: An accurate prognosis could be obtained at 24 hours after admission by evaluating the change in total leukocyte, band neutrophil, lymphocyte, monocyte, and eosinophil counts.

BCG-malaria co-Infection has paradoxical effects on C57BL/6 and A/J mouse strains.

Bacillus Calmette-Guérin (BCG) infection of the spleen is a potent modifier of splenic function. Prior to malaria infection, we infected two mouse strains of differing susceptibility to Plasmodium chabaudi AS (C57BL/6 and A/J) with this mycobacterium. We then evaluated aspects of spleen cell composition, architecture and cytokine expression, and correlated these with the outcome. BCG preinfection resulted in protection of the A/J mice but paradoxically resulted in mortality of the C57BL/6 mice. The latter developed higher parasitaemias that peaked earlier than the A/J mice rendered resistant by BCG. BCG infection induced remarkable changes to splenic histology examined by H&E staining, but there were no consistent differences between mouse strains. C57BL/6 mice had higher absolute numbers of all immune cell phenotypes than did A/J mice, and higher macrophage and dendritic cell proportions. BCG-induced resistance in A/J mice was associated with an increased CD4+ expression of IFN-gamma whilst induced death in C57BL/6 mice was associated with excessive IFN-gamma expression. A moderate TH1 response in the A/J model may have been responsible for the improved survival, and an excessive TH1 response in the C57BL/6 model may have contributed to their death.

Molecular characterisation of Babesia gibsoni infection from a pit-bull terrier pup recently imported into South Africa.

Canine babesiosis caused by Babesia gibsoni was diagnosed in a 3-month-old Pit-bull pup during a routine clinical examination. Diagnosis was confirmed by way of smear examination, PCR, Reverse Line Blot (RLB) and sequence analysis which showed 100% homology with B. gibsoni (Japan AB118032) and Babesia sp. (Oklahoma) (AF205636). Haematology showed moderate anaemia and severe thrombocytopenia. Treatment was initiated with diminazene aceturate (Berenil RTU) followed by 2 doses of imidocarb diproprionate (Forray-65) 3 days and 14 days later, respectively. Babesia gibsoni DNA was still detectable 2 weeks post-treatment on the PCR/RLB test. A 10-day course of combination drug therapy using atovaquone and azithromycin was initiated. Blood samples taken on Day 1 and Day 40 after completion of treatment were negative for B. gibsoni DNA on PCR/RLB test. The implications of a possible introduction of B. gibsoni into South Africa are discussed.

The elevated serum urea:creatinine ratio in canine babesiosis in South Africa is not of renal origin.

Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.

Comparison of effects of uncomplicated canine babesiosis and canine normovolaemic anaemia on abdominal splanchnic Doppler characteristics--a preliminary investigation.

A preliminary study was conducted to compare uncomplicated canine babesiosis (CB) and experimentally induced normovolaemic anaemia (EA) using Doppler ultrasonography of abdominal splanchnic vessels. Fourteen dogs with uncomplicated CB were investigated together with 11 healthy Beagles during severe EA, moderate EA and the physiological state as a control group. Canine babesiosis was compared with severe EA, moderate EA and the physiological state using Doppler variables of the abdominal aorta, cranial mesenteric artery (CMA), coeliac, left renal and interlobar, and hilar splenic arteries, and the main portal vein. Patterns of haemodynamic changes during CB and EA were broadly similar and were characterised by elevations in velocities and reductions in resistance indices in all vessels except the renal arteries when compared with the physiological state. Aortic and CMA peak systolic velocities and CMA end diastolic and time-averaged mean velocities in CB were significantly lower (P < 0.023) than those in severe EA. Patterns of renal haemodynamic changes during CB and EA were similar. However, the renal patterns differed from those of aortic and gastrointestinal arteries, having elevations in vascular resistance indices, a reduction in end diastolic velocity and unchanged time-averaged mean velocity. The left renal artery resistive index in CB was significantly higher (P < 0.025) than those in EA and the physiological state. Renal interlobar artery resistive and pulsatility indices in CB were significantly higher (P < 0.016) than those of moderate EA and the physiological state. The similar haemodynamic patterns in CB and EA are attributable to anaemia, while significant differences may additionally be attributed to pathophysiological factors peculiar to CB.