A retrospective study of the therapeutic efficacy of doxycycline on concurrent canine ehrlichiosis and babesiosis in a veterinary hospital population

Doxycycline has a well known broad spectrum activity against bacteria and rickettsia, as well as Ehrlichia spp. However, the use of doxycycline for the treatment of concurrent ehrlichiosis and babesiosis has rarely been evaluated, especially in veterinary hospital populations. A retrospective study of 70 canine ehrlichiosis and 12 canine babesiosis concurrent infections from Out Patient Department patients at Chulalongkorn Small Animal Teaching Hospital, admitted during 2001–2003, were studied. The results showed a complete curative effect of doxycycline on both canine ehrlichiosis and canine babesiosis concurrent infections. The red blood cell indices after treatment were significantly higher in canine ehrlichiosis (P < 0.05). The platelet cell counts after treatment were significantly higher in concurrent canine ehrlichiosis and babesiosis infections (P < 0.05). Doxycycline can be recommended as the drug of choice for both canine ehrlichiosis and canine babesiosis and concurrent infections of both conditions in veterinary hospitals.     

A retrospective study of clinical hematology and biochemistry of canine babesiosis on hospital populations in Bangkok, Thailand

Although canine babesiosis is an important tick-borne disease in Thailand, there are few studies evaluating the clinicopathological findings in dogs naturally infected with Babesia. To further characterize and describe these findings, 127 dogs in the out-patient department of the Small Animal Teaching Hospital were evaluated for canine babesiosis by means of physical, hematological, and biochemical examinations, during the period January 2001–December 2003. The hematological findings in most of these dogs were hypocytic hypochromic anemia and thrombocytopenia. The total and differential leukocyte counts were not specific. Biochemical values were within normal ranges but serum biochemistry varied for each dog. This retrospective study indicated that Babesia infection in dogs apparently caused anemia and thrombocytopenia, while other clinical values did not change. The observations can be used as a significant database and reference for canine babesiosis in small animal hospital populations worldwide, especially in endemic areas.     

Disturbance of thyroid function in canine ehrlichiosis and babesiosis associated with oxidative stress

Canine babesiosis and ehrlichiosis are endemic in India. The effect of these diseases on hematological and clinical biochemistry is well established; however, the association with thyroid function and oxidative stress is not known. Accordingly, we assessed the thyroid function and oxidative stress in the dogs with babesiosis (n = 8) and ehrlichiosis (n = 10) based on the blood smear examination. Non-infected dogs (n = 8) served as control. Assay of plasma free triiodothyronine (FT3) and free thyroxine (FT4) was done by enzyme-linked immunosorbent assay (ELISA); plasma malondialdehyde (MDA) and nitric oxide (NOx) were done by spectrophotometric method. Hematology was done in the blood using Na₂ ethylenediaminetetraacetic acid (Na₂ EDTA) as anticoagulant. Plasma FT3 and FT4 were significantly decreased by 1.79 to 1.82 pg/mL and 0.85 to 0.88 ng/dL, respectively, in the dogs with babesiosis or ehrlichiosis (P < 0.01). In contrast, plasma MDA and NOx were significantly increased by 2.904 to 3.576 nM/mL and 3.725 to 5.04 μM/mL, respectively, in the presence of infection (P < 0.01). Hematology showed anemia (P < 0.01), leukocytosis (P < 0.01), and lymphopenia (P < 0.01) in the presence of either Babesia gibsoni or Ehrlichia canis as compared to non-infected dog. The results indicated that hypothyroidism with concurrent oxidative stress might be responsible for pathophysiology in dogs with B. gibsoni and E. canis infection besides hematological crisis.     

Canine dirofilariasis and concurrent tick-borne transmitted diseases in Bangkok, Thailand

A retrospective study in dogs presented to the Chulalongkorn Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, from January 2001 to December 2003 was carried out. A total of 917 dogs were diagnosed with canine dirofilariasis and other concurrent tick-borne transmitted diseases by the Veterinary Diagnostic Laboratory, Faculty of Veterinary Science, Chulalongkorn University. The highest occurrence within each year was observed in November 2001 (40 cases), April 2002 (41 cases), and July 2003 (36 cases), respectively. Of the total 917 positive cases, a single infection of dirofilariasis was detected in 869 dogs (94.8%; group 1), while 37 dogs (4.0%; group 2) were diagnosed with dirofilariasis and ehrlichiosis, 4 dogs (0.4%; group 3) with dirofilariasis and hepatozoonosis, and 7 dogs (0.8%; group 4) with dirofilariasis, ehrlichiosis, and babesiosis, respectively. Laboratory data comprising hematological and blood chemistry profiles were evaluated and compared among groups. Group 4 was defined as moderate microcytic anemia and was significantly different with regard to hematological profiles from others (P < 0.05). In addition, severe thrombocytopenia was observed in both groups 2 and 4 (65.4 × 10³ and 59.0 × 10³ cells/μl, respectively). The hepatobiliary profiles in all groups revealed increases in serum alanine aminotransferase and serum alkaline phosphatase activities indicative of hepatocellular damage. These epidemiological results serve as baseline information for preventive strategies against blood parasites in the endemic area. Moreover, both biochemical and hematological abnormalities should be considered as appropriate monitors during disease interventions.     

Seasonal occurrence of canine babesiosis is influenced by local climate conditions

Global warming and its effect on local climate conditions is one of the presumed underlying causes for changes in temporal and spatial distribution of vector-borne diseases. In Europe, canine babesiosis is transmitted by Dermacentor reticulatus. This hard tick species is observed to spread to new endemic areas. Within these new areas, specific local climate conditions may be responsible for sudden seasonal onset and termination of occurrence of this disease in dogs. From 2000 to 2006, 343 confirmed cases of canine babesiosis were documented at the Veterinary University of Vienna and in the Laboratory for Veterinary Diagnostic (INVITRO, Vienna). Estimated week of infection was analysed for mean air and soil temperature, relative humidity, and precipitation for each case. For seasonal start in spring, a sudden rise of air temperature up to 12 °C and defrosting of soil were essential. In autumn, the seasonal start was associated with a drop of temperature below 17 °C. Termination of occurrence of canine babesiosis, independent of season, correlated either with a sudden drop of temperature (ΔT>9 °C) with concurrent heavy rain, persistent drought, or with air temperature above 20 °C (spring/summer) or below 5 °C (autumn/winter). Relative humidity and precipitation did not have a major influence on the incidence of canine babesiosis at all. Global climate changes and adaptation of ticks to new environmental conditions introduce vector-borne diseases into new areas.     

Expression and function of triggering receptor expressed on myeloid cells-1 (TREM-1) on canine neutrophils

The dog is both a valued veterinary species and a widely used translational model for sepsis research. However, relatively little work has been performed evaluating potential biomarkers present during canine infection. Triggering receptor expressed on myeloid cells-1 (TREM-1) has shown promise as a biomarker for infection and pneumonia in humans. Here we describe, for the first time, the expression and function of the canine orthologue of TREM-1. Expression of TREM-1 on canine neutrophils is significantly up-regulated by stimulation with microbial agonists of TLR2/6, TLR1/2, and TLR4/MD2. Kinetics of TREM-1 protein up-regulation are rapid, with significant increases observed within 2 hr of neutrophil activation. Functionally, canine TREM-1 synergistically enhances LPS-induced production of IL-8, TNF-α and a canine orthologue of CXCL1. Collectively, these data suggest that TREM-1 expression in dogs, as it is in humans, is an amplifier of pro-inflammatory responses to microbial products. These results have direct application to veterinary diagnostics as well as the potential to enhance the utility of canine disease models in the assessment of potential therapeutics in the treatment of human sepsis.     

A retrospective study of the clinical hematology and biochemistry of canine ehrlichiosis in an animal hospital population in Bangkok, Thailand

A retrospective study on 687 canine ehrlichiosis cases was carried out during January 2001–December 2003 at the Chulalongkorn Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University. Data on rectal temperature, clinical hematology, and biochemistry were analyzed on the first day of admission. The highest incidences each year were observed in December 2001 (24 cases), June and July 2002 (31 cases each), and October 2003 (38 cases). The clinical findings varied, although most cases showed a high fever (33%), severe anemia (18%), leukocytosis (18%) or leukopenia (19%), thrombocytopenia (93%), and hepatic enzyme elevation. It followed that the therapeutic plan should comprise both specific and clinically supportive treatments, including hematotonics and hepatotonics.     

Reactivity of purified lectins with blood typed canine erythrocytes

Agglutination tests were performed with 40 commercially available lectins and a panel of blood typed canine erythrocytes. Erythrocytes were obtained from 17 dogs (two poodles, two black labradors, five greyhounds and eight beagles). The erythrocytes expressed various combinations of dog erythrocyte antigens (DEA) 1.1, 1.2 or null, 4 and 7. Lectin reactivity with untreated, ficin treated, and neuraminidase-treated cells was determined. No correlation between lectin reactivity and the canine blood group antigens expressed on the red cell test panel was found. Results suggest that some canine erythrocytes may be differentiated from others on the basis of reactivity with Phytolacca americana and Glycine max lectins.     

Predominance of Ehrlichia ewingii in Missouri dogs

To investigate the species distribution of Ehrlichia present in Missouri dogs, we tested 78 dogs suspected of having acute ehrlichiosis and 10 healthy dogs. Blood from each dog was screened with a broad-range 16S rRNA gene PCR assay that detects known pathogenic species of Ehrlichia and ANAPLASMA: The species was determined by using species-specific PCR assays and nucleotide sequencing. Ehrlichia antibody testing was performed by using an indirect immunofluorescence assay with Ehrlichia chaffeensis as the antigenic substrate. The broad-range assay detected Ehrlichia or Anaplasma DNA in 20 (26%) of the symptomatic dogs and 2 (20%) of the asymptomatic dogs. E. ewingii accounted for 20 (91%), and E. chaffeensis accounted for 1 (5%) of the positives. Anaplasma phagocytophilum DNA was detected in one dog, and the sequences of regions of the 16S rRNA gene and the groESL operon amplified from the blood of this dog matched the published sequences of this organism. Antibodies reactive with E. chaffeensis were detected in 14 (67%) of the 21 PCR-positive dogs and in 12 (19%) of the 64 PCR-negative dogs. Combining the results of PCR and serology indicated that 33 (39%) of 85 evaluable dogs had evidence of past or current Ehrlichia infection. We conclude that E. ewingii is the predominant etiologic agent of canine ehrlichiosis in the areas of Missouri included in this survey. E. canis, a widely recognized agent of canine ehrlichiosis, was not detected in any animal. The finding of E. ewingii in asymptomatic dogs suggests that dogs could be a reservoir for this Ehrlichia species.     

Clinicopathological study of experimentally induced canine monocytic ehrlichiosis

The aims of this study are to investigate the hematology, blood chemistry, pathological study, including macroscopic and microscopic lesions, of experimentally induced canine monocytic erhlichiosis in Thailand and to demonstrate the distribution of Ehrlichia canis in target organs by nested polymerase chain reaction (PCR). Five experimental healthy dogs were inoculated with 5 ml of whole blood (estimated number of E. canis morulae 15 × 10^–5% per monocytes) from the splenectomized dog via the saphenous vein. Two healthy dogs served as a negative control. Hematology revealed nonregenerative normocytic normochromic anemia, thrombocytopenia and mild leukopenia. Blood chemistry revealed an increase in aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AP), hypoproteinemia, hypoalbuminemia, and hyperglobulinemia by day 66 post-inoculation. Pathology revealed anemia, ascites, jaundice, interstitial pneumonia, splenomegaly, generalized lymphadenopathy, and severe fatty liver. The detection of E. canis was performed using tissue embedded in paraffin wax by nested PCR showing positive in all target organs. This study concluded that acute induced experimental canine monocytic ehrlichiosis can cause significant clinical and pathological lesions.     

Bone marrow transplantation in canine GM1 gangliosidosis

Allogeneic bone marrow transplantation was carried out in an 81-day-old Portuguese water dog with GM1 gangliosidosis using a DLA identical sibling as donor. Engraftment was complete and beta-galactosidase activity in leukocytes of the transplanted dog were similar to those in the donor. Over the next 2.5 months neurological deterioration in the transplanted dog was similar to that in untreated dogs with GM1 gangliosidosis. Cerebral ganglioside GM1 concentrations were not diminished by bone marrow transplantation and cerebral beta-galactosidase activity was negligible. We conclude that allogeneic bone marrow transplantation early in life is ineffective in canine GM1 gangliosidosis.     

Canine babesiosis in Romania due to <Emphasis Type="Italic">Babesia canis</Emphasis> and <Emphasis Type="Italic">Babesia vogeli</Emphasis>: a molecular approach

Canine babesiosis is a tick-borne disease caused by the protozoa Babesia spp. that affects dogs worldwide. In Romania, canine babesiosis has become quite frequent in the last few years, with a wide variety of clinical signs, ranging from mild, nonspecific illness to peracute collapse, and even death. Traditionally, a Babesia infection in dogs is diagnosed based on the morphologic appearance of the intraerythrocytic piroplasms observed in peripheral blood smears. To date, no data on genetic characterization of Babesia species in dogs has been documented for Romania. Therefore, a molecular survey on natural Babesia infections of dogs in Romania using polymerase chain reaction and genetic sequence analysis of a fragment of the ssRNA gene was performed. A total number of 16 blood samples were tested for the presence of Babesia DNA. Blood samples were collected from 11 dogs with symptoms of babesiosis and microscopically proven positive for Babesia and from a group of five asymptomatic dogs, not tested microscopically for Babesia, which were included in the study for comparative analysis. The piroplasm-specific PCR amplifying the partial 18S rRNA gene confirmed Babesia spp. infection in all 11 samples from dogs with clinical babesiosis, and in one of the clinically normal dogs. Sequence analysis revealed the presence of Babesia canis in all clinically affected dogs and Babesia vogeli in one clinically normal dog. This is the first molecular evidence of B. canis and B. vogeli in dogs from Romania. The results of the study provide basic information toward a better understanding of the epidemiology of canine babesiosis in Romania and will help to promote an effective control program.     

Molecular and seroepidemiological evidence of canine calicivirus infections in Japan

Calicivirus infection of dogs was epidemiologically investigated by using canine calicivirus (CaCV) strain 48 as a reference. Similar RNA polymerase gene sequences and neutralizing antibodies against CaCV were detected in 1.7% of clinical specimens and 57% of serum samples, respectively, suggesting a high prevalence of CaCV in dog populations.     

Serologic evidence of canine and equine ehrlichiosis in northeastern United States.

In a retrospective study, indirect fluorescent-antibody staining methods were used to detect immunoglobulins to Ehrlichia canis and Ehrlichia risticii in canine and equine sera that had originally been analyzed for antibodies to Borrelia burgdorferi. Analyses of 60 dog serum specimens collected in Connecticut and New York State during 1986 revealed antibodies to E. canis in 7 (11.7%) specimens; titration endpoints ranged from 1:40 to 1:320. Three of these dogs had anemia. Of the 187 equine serum specimens obtained in Connecticut during 1985 and analyzed by indirect fluorescent-antibody staining methods, 17 (9.1%) contained antibodies to E. risticii. Maximal antibody titers of 1:1,280 were recorded for serum specimens collected from three equids during May and July. We conclude that canine and equine ehrlichiosis coexist with Lyme borreliosis in Connecticut and the lower Hudson River Valley of New York State.     

L-2-hydroxyglutaric aciduria: characterisation of the molecular defect in a spontaneous canine model

l-2-hydroxyglutaric aciduria (l-2-HGA) is a neurometabolic disorder that produces a variety of clinical neurological deficits, including psychomotor retardation, seizures and ataxia. The biochemical hallmark of l-2-HGA is the accumulation of l-2-hydroxyglutaric acid (l-2-HG) in cerebrospinal fluid, plasma and urine. Mutations within the gene L2HGDH (Entrez Gene ID 79944) on chromosome 14q22 encoding L-2-hydroxyglutaric acid dehydrogenase have recently been shown to cause l-2-HGA in humans. Using a candidate gene approach in an outbred pet dog population segregating l-2-HGA, the causal molecular defect was identified in the canine homologue of L2HGDH and characterised. DNA sequencing and pedigree analysis indicate a common founder effect in the canine model. The canine model shares many of the clinical and MRI features of the disease in humans and represents a valuable resource as a spontaneous model of l-2-HGA.     

Seroprevalence of canine babesiosis in Hungary suggesting breed predisposition

Six hundred fifty-one blood samples were collected from urban and rural dogs in various parts of Hungary to measure antibody levels to Babesia canis with indirect fluorescent antibody test. Thirty-seven (5.7%) of the sera showed positivity with titers between 1:80 and 1:10,240. Seroconverted dogs were found in 13 locations of the country. It is concluded that canine babesiosis is becoming more prevalent in Eastern Hungary. Seropositivity increased then declined with age, reaching a maximum in case of 3.1- to 5-year-old dogs. Prevalence of antibodies to B. canis was significantly higher among german shepherds and komondors. This suggests a genetic predisposition of german shepherd dogs to chronic babesiosis (carrier status) with long-term maintenance of their seropositivity. On the other hand, heavy-coated komondors are phenotypically more suitable for repeated exposure to ticks, potentially infected with B. canis. This is the first report on the seroprevalence of canine babesiosis in Hungary.     

Increased serum urea to creatinine ratio and its negative correlation with arterial pressure in canine babesiosis

The increase of the serum urea to creatinine ratio (UCR) was observed in dogs infected with Babesia canis. Previous studies have suggested that decrease of blood pressure can be one of the reasons for this phenomenon. In this work statistically significant increase of the UCR was observed in dogs with babesiosis. Comparison of the UCR between 23 azotaemic dogs and 25 non-azotaemic dogs infected with Babesia canis showed statistically significantly higher mean of the UCR in azotaemic dogs. Correlations between UCR and systolic, diastolic and mean arterial pressure (SAP, DAP and MAP) in 48 dogs infected with B. canis were negative (UCR and SAP: r = ?0.3909; UCR and DAP: r = ?0.3182; UCR and MAP: r = ?0.3682) and statistically significant (p < 0.05). This result may indicate contribution of hypotension in the increase of the UCR in canine babesiosis. However, the correlations were not high, and there was no statistically significant correlation between UCR and arterial pressures in azotaemic dogs. Thus, it seems that decrease of blood pressure in dogs with babesiosis explains only partially the cause of increased UCR in infected dogs. The other authors suggested hyperureagenesis and myocardial injury as a potential reason for the increased UCR in canine babesiosis. Thus, further studies are needed to determine causes of increased UCR in dogs with babesiosis, especially on the connection between UCR changes and the concentrations of plasma cardiac troponins and ammonia, and the occurrence of occult blood on fecal examination.     

Evolution of canine and equine influenza (H3N8) viruses co-circulating between 2005 and 2008

Influenza virus, subtype H3N8, was transmitted from horses to greyhound dogs in 2004 and subsequently spread to pet dog populations. The co-circulation of H3N8 viruses in dogs and horses makes bi-directional virus transmission between these animal species possible. To understand the dynamics of viral transmission, we performed virologic surveillance in dogs and horses between 2005 and 2008 in the United States. The genomes of influenza A H3N8 viruses isolated from 36 dogs and horses were sequenced to determine their origin and evolution. Phylogenetic analyses revealed that H3N8 influenza viruses from horses and dogs were monophyletic and distinct. There was no evidence of canine influenza virus infection in horses with respiratory disease or new introductions of equine influenza viruses into dogs in the United States. Analysis of a limited number of equine influenza viruses suggested substantial separation in the transmission of viruses causing clinically apparent influenza in dogs and horses.     

Adaptation of canine distemper virus to canine footpad keratinocytes modifies polymerase activity and fusogenicity through amino acid substitutions in the P/V/C and H proteins

The wild-type canine distemper virus (CDV) strain A75/17 induces a non-cytocidal infection in cultures of canine footpad keratinocytes (CFKs) but produces very little progeny virus. After only three passages in CFKs, the virus produced 100-fold more progeny and induced a limited cytopathic effect. Sequence analysis of the CFK-adapted virus revealed only three amino acid differences, of which one was located in each the P/V/C, M and H proteins. In order to assess which amino acid changes were responsible for the increase of infectious virus production and altered phenotype of infection, we generated a series of recombinant viruses. Their analysis showed that the altered P/V/C proteins were responsible for the higher levels of virus progeny formation and that the amino acid change in the cytoplasmic tail of the H protein was the major determinant of cytopathogenicity.