Andrew L. Leisewitz

Effect of early enteral nutrition on intestinal permeability, intestinal protein loss, and outcome in dogs with severe parvoviral enteritis.

A randomized, controlled clinical trial investigated the effect of early enteral nutrition (EN) on intestinal permeability, intestinal protein loss, and outcome in parvoviral enteritis. Dogs were randomized into 2 groups: 15 dogs received no food until vomiting had ceased for 12 hours (mean 50 hours after admission; NPO group), and 15 dogs received early EN by nasoesophageal tube from 12 hours after admission (EEN group). All other treatments were identical. Intestinal permeability was assessed by 6‐hour urinary lactulose (L) and rhamnose (R) recoveries (%L, %R) and L/R recovery ratios. Intestinal protein loss was quantified by fecal α1‐proteinase inhibitor concentrations (α1‐PI). Median time to normalization of demeanor, appetite, vomiting, and diarrhea was 1 day shorter for the EEN group for each variable. Body weight increased insignificantly from admission in the NPO group (day 3: 2.5±2.8% day 6: 4.3±2.3% mean ± SE), whereas the EEN group exhibited significant weight gain (day 3: 8.1±2.7% day 6: 9.7 ± 2.1%). Mean urinary %L was increased, %R reduced, and L/R recovery ratios increased compared to reference values throughout the study for both groups. Percent lactulose recovery decreased in the EEN group (admission: 22.6±8.0% day 6: 17.9 ± 2.3%) and increased in the NPO group (admission: 11.0±2.6% day 6: 22.5 ± 4.6%, P= .035). Fecal α1‐PI was above reference values in both groups and declined progressively. No significant differences occurred for %R, L/R ratios, or α1‐PI between groups. Thirteen NPO dogs and all EEN dogs survived (P= .48). The EEN group showed earlier clinical improvement and significant weight gain. The significantly decreased %L in the EEN versus NPO group might reflect improved gut barrier function, which could limit bacterial or endotoxin translocation.

Molecular detection of tick-borne protozoal and ehrlichial infections in domestic dogs in South Africa.

A total of 1,138 blood specimens were collected over a 6-year period (2000-2006) from domestic dogs in South Africa. Specimens from domestic dogs were obtained from the Onderstepoort Veterinary Academic Hospital (OVAH) in Pretoria, the Society for the Prevention of Cruelty to Animals (Johannesburg, Durban, East London and Bloemfontein) and private practices from four provinces (Gauteng, Mpumalanga, KwaZulu-Natal and Western Cape). All specimens were screened for Babesia, Theileria, Hepatozoon and Ehrlichia/Anaplasma species using PCR and Reverse Line Blot (RLB) assays. On RLB, 560/1,137 domestic dog-specimens were positive for one or more parasites. Of the positive domestic dog-specimens, 420 (75%) were infected with Babesia rossi; 82 (15%) dogs were infected with Theileria sp. (dog); 18 (3%) dogs were infected with Babesia vogeli; 14 (3%) specimens were infected with Ehrlichia canis. Mixed infections were also found: B. rossi and E. canis were detected in 12 (2%) specimens; B. vogeli and E. canis occurred in 7 (1%) specimens; Theileria sp. (dog) and E. canis in 3 (0.5%) specimens; B. rossi and B. vogeli in one specimen. B. rossi, B. vogeli and E. canis occurred simultaneously in one dog. There was also one incidental finding of a dog positive for Trypanosoma congolense. The results indicate that a wide range of tick-borne pathogens are circulating in the canine populations in South Africa.

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.

Molecular detection of Babesia rossi and Hepatozoon sp. in African wild dogs (Lycaon pictus) in South Africa.

Blood specimens from wild dogs (n=301) were obtained from De Wildt Cheetah and Wildlife Centre (Pretoria) and five game reserves (4 in the North-West Province and 1 in Limpopo Province), South Africa. Specimens were screened for Babesia, Theileria, Hepatozoon and Ehrlichia/Anaplasma species using PCR and Reverse Line Blot (RLB) assays. Positive results were obtained in 18 (6%) wild dogs. Sixteen specimens were found positive for Babesia rossi and two dogs were Hepatozoon sp. positive. It appears that these tick-borne pathogens are not widely distributed in wild dog populations.

The synergistic action of imidacloprid and flumethrin and their release kinetics from collars applied for ectoparasite control in dogs and cats.

BackgroundThe control of tick and flea burdens in dogs and cats has become essential to the control of important and emerging vector borne diseases, some of which are zoonoses. Flea worry and flea bite hypersensitivity are additionally a significant disease entity in dogs and cats. Owner compliance in maintaining the pressure of control measures has been shown to be poor. For these reasons efforts are continuously being made to develop ectoparasiticides and application methods that are safe, effective and easy to apply for pet owners. A new polymer matrix collar has recently been developed which is registered for 8 months use in cats and dogs. The basic properties of this collar have been investigated in several in vitro and in vivo studies.MethodsThe effects of imidacloprid, flumethrin and the combination were evaluated in vitro by means of whole cell voltage clamp measurement experiments conducted on isolated neuron cells from Spodoptera frugiperda. The in vitro efficacy of the two compounds and the combination against three species of ticks and their life stages and fleas were evaluated in a dry surface glass vial assay. The kinetics of the compounds over time in the collar were evaluated by the change in mass of the collar and measurement of the surface concentrations and concentrations of the actives in the collar matrix by HPLC. Hair clipped from collar treated dogs and cats, collected at various time points, was used to assess the acaricidal efficacy of the actives ex vivo.ResultsAn in vitro isolated insect nerve model demonstrated the synergistic neurotoxic effects of the pyrethroid flumethrin and the neonicotinoid imidacloprid. An in vitro glass vial efficacy and mortality study against various life stages of the ticks Ixodes ricinus, Rhipicephalus sanguineus and Dermacentor reticulatus and against the flea (Ctenocephalides felis) demonstrated that the combination of these products was highly effective against these parasites. The release kinetics of these actives from a neck collar (compounded with 10% imidacloprid and 4.5% flumethrin) was extensively studied in dogs and cats under laboratory and field conditions. Acaricidal concentrations of the actives were found to be consistently released from the collar matrix for 8 months. None of the collar studies in dogs or cats were associated with any significant collar related adverse event.ConclusionHere we demonstrated the synergism between the pyrethroid flumethrin and the neonicotinoid imidacloprid, both provided in therapeutically relevant doses by a slow release collar matrix system over 8 months. This collar is therefore a convenient and safe tool for a long-term protection against ectoparasites.

Excessive Pro-Inflammatory Serum Cytokine Concentrations in Virulent Canine Babesiosis.

Babesia rossi infection causes a severe inflammatory response in the dog, which is the result of the balance between pro- and anti-inflammatory cytokine secretion. The aim of this study was to determine whether changes in cytokine concentrations were present in dogs with babesiosis and whether it was associated with disease outcome. Ninety-seven dogs naturally infected with B. rossi were studied and fifteen healthy dogs were included as controls. Diagnosis of babesiosis was confirmed by polymerase chain reaction and reverse line blot. Blood samples were collected from the jugular vein at admission, prior to any treatment. Cytokine concentrations were assessed using a canine-specific multiplex assay on an automated analyser. Serum concentrations of interleukin (IL)-2, IL-6, IL-8, IL-10, IL-18, granulocyte-macrophage colony stimulating factor (GM-CSF) and monocyte chemotactic protein-1 (MCP-1) were measured. Twelve of the Babesia-infected dogs died (12%) and 85 survived (88%). Babesia-infected dogs were also divided into those that presented within 48 hours from displaying clinical signs, and those that presented more than 48 hours after displaying clinical signs. Cytokine concentrations were compared between the different groups using the Mann-Whitney U test. IL-10 and MCP-1 concentrations were significantly elevated for the Babesia-infected dogs compared to the healthy controls. In contrast, the IL-8 concentration was significantly decreased in the Babesia-infected dogs compared to the controls. Concentrations of IL-6 and MCP-1 were significantly increased in the non-survivors compared to the survivors. Concentrations for IL-2, IL-6, IL-18 and GM-CSF were significantly higher in those cases that presented during the more acute stage of the disease. These findings suggest that a mixed cytokine response is present in dogs with babesiosis caused by B. rossi, and that an excessive pro-inflammatory response may result in a poor outcome.

Clinicopathologic abnormalities associated with snake envenomation in domestic animals

Envenomation of domestic animals by snakes occurs frequently in certain geographic areas. However, reports describing clinical signs, clinicopathologic abnormalities, therapeutic approaches, and outcomes are sparse. This review summarizes various snake families, venom types associated with harmful snakes, and the significant hematologic, hemostatic, and biochemical abnormalities associated with envenomation. Hematologic abnormalities include RBC membrane abnormalities, hemolysis, hemoconcentration, leukogram changes, and platelet abnormalities, specifically thrombocytopenia. Coagulopathies associated with snake envenomation are well described in human medicine, and many studies have demonstrated properties of venoms that lead to both procoagulation and anticoagulation. As expected, similar abnormalities have been described in domestic animals. Biochemical abnormalities are associated with the effects of venom on tissues such as liver, skeletal and cardiac muscle, vascular endothelium, and kidney as well as effects on protein components and cholesterol. This comprehensive review of clinicopathologic abnormalities associated with envenomation and their relationships to characterized venom constituents should be useful both in the diagnosis and management of envenomation and should serve as a foundation for future research in this field.

Preliminary Evaluation of the BrEMA1 Gene as a Tool for Associating Babesia rossi Genotypes and Clinical Manifestation of Canine Babesiosis

ABSTRACT 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.

A prospective, randomized comparison of Oxyglobin (HB‐200) and packed red blood cell transfusion for canine babesiosis

OBJECTIVE To establish the efficacy of Oxyglobin (HB-200) in canine babesiosis and compare it to standard therapy, packed red blood cell transfusion (pRBCT) with respect to improvements in specific parameters of blood gas, acid-base, blood pressure, and subjective evaluations. DESIGN Prospective, randomized, clinical trial. SETTING Onderstepoort Veterinary Academic Hospital. ANIMALS Twelve dogs (8-25 kg) naturally infected with Babesia rossi and a hematocrit of 0.1-0.2 L/L (10-20%). INTERVENTIONS Treatment groups were randomized to receive either 20 mL/kg of Oxyglobin or pRBCT over 4 hours via a central venous catheter. Transfusions were followed by lactated Ringers solution infusion. Rectal temperature, femoral arterial and mixed venous blood sampling, oscillometric blood pressure, and subjective assessment of patient status (habitus), and appetite were performed at time points 0, 1, 4, 8, 24, 48, and 72 hours. MAIN RESULTS Dogs presented with a hypoalbuminemic alkalosis; hyperchloremic, dilutional acidosis; normotensive tachycardia; pyrexia; depression; and anorexia. Both treatments produced similar results, with the exception of significant differences in pH (4 h); PCO(2) (4 h); hemoglobin (8 h, 24 h); mean arterial pressure (48 h); albumin (4 h, 8 h); habitus (8 h, 48 h); and appetite (24 h). Arterial O(2) content was higher for pRBCT than Oxyglobin at 72 hours, but central venous PO(2) did not differ between groups or over time and was consistently subnormal. CONCLUSIONS Oxyglobin provides similar overall improvements to pRBCT in dogs with anemia from babesiosis, with respect to blood gas, acid-base and blood pressure, although patients receiving packed cells tended to have more rapid normalization of habitus and appetite.