Identification and antimicrobial susceptibility of microorganisms isolated from severe corneal ulcers of dogs in Thailand.

This study aims to determine the microbiological profile and risk factors associated with antimicrobial-resistant bacteria in canine severe corneal ulcers. Thirty-two corneal and conjunctival swabs were collected from dogs with diagnosed severe corneal ulcers that presented to Prasu-Arthorn veterinary teaching hospital in Nakhon Pathom, Thailand from June 2015 to June 2016. Microorganisms were identified by means of genotypic and phenotypic approaches. Of 32 ulcers sampled, 26 (81.3%) yielded culturable microorganisms with 24 bacterial isolates and 7 fungal isolates. The most commonly isolated bacteria were Staphylococcus spp. (45.8%, 11/24) and Pseudomonas aeruginosa (20.8%, 5/24). Out of 11 staphylococcal isolates identified, 10 carried the mecA gene providing methicillin resistance. The extended-spectrum ß-lactamase (ESBL) encoding genes blaCTX-M and blaVEB-1 were found in an Acinetobacter lwoffii isolate, and blaSHV was found in a P. aeruginosa isolate. Based on the Clinical Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint criteria, minimum inhibitory concentrations values showed that all bacteria, except for staphylococci, were susceptible to current ophthalmic antibiotics. More than 50% of staphylococci were resistant to all generations of fluoroquinolones and fusidic acid. Chloramphenicol was highly active against staphylococci (81.3% susceptible). The width (P=0.02) and the depth (P=0.04) of ulcers predicted greater risk of yielding resistant bacteria. The identification of antimicrobial-resistant bacteria prompts practitioners to be prudent when choosing ophthalmic antibiotics for severe corneal ulcers.

Molecular detection and genetic diversity of bovine Babesia spp., Theileria orientalis, and Anaplasma marginale in beef cattle in Thailand.

Babesia spp., Theileria orientalis, and Anaplasma marginale are significant tick-borne pathogens that affect the health and productivity of cattle in tropical and subtropical areas. In this study, we used PCR to detect the presence of Babesia bovis, Babesia bigemina, and T. orientalis in 279 beef cattle from Western Thailand and A. marginale in 608 beef cattle from the north, northeastern, and western regions. The PCRs were performed using species-specific primers based on the B. bovis spherical body protein 2 (BboSBP2), B. bigemina rhoptry-associated protein 1a (BbiRAP-1a), T. orientalis major piroplasm surface protein (ToMPSP), and A. marginale major surface protein 4 (AmMSP4) genes. To determine the genetic diversity of the above parasites, amplicons of B. bovis and B. bigemina ITS1-5.8s rRNA gene-ITS2 regions (B. bovis ITS, B. bigemina ITS), ToMPSP, and AmMSP4 genes were sequenced for phylogenetic analysis. PCR results revealed that the prevalence of B. bovis, B. bigemina, T. orientalis, and A. marginale in the Western region was 11.1, 12.5, 7.8, and 39.1 %, respectively. Coinfections of two or three parasites were observed in 17.9 % of the animals sampled. The study revealed that the prevalence of A. marginale in the western region was higher than in the north and northeastern regions (7 %). Sequence analysis showed the BboSBP2 gene to be more conserved than B. bovis ITS in the different isolates and, similarly, the BbiRAP-1a was more conserved than B. bigemina ITS. In the phylogenetic analysis, T. orientalis MPSP sequences were classified into types 3, 5, and 7 as previously reported. A. marginale MSP4 gene sequences shared high identity and similarity with each other and clustered with isolates from other countries. This study provides information on the prevalence and genetic diversity of tick-borne pathogens in beef cattle and highlights the need for effective strategies to control these pathogens in Thailand.

Molecular epidemiology of bovine Babesia spp. and Theileria orientalis parasites in beef cattle from northern and northeastern Thailand.

Beef cattle production represents the largest cattle population in Thailand. Their productivity is constrained by tick-borne diseases such as babesiosis and theileriosis. In this study, we determined the prevalence of Babesia bigemina, Babesia bovis and Theileria orientalis using polymerase chain reaction (PCR). The genetic markers that were used for detection of the above parasites were sequenced to determine identities and similarity for Babesia spp. and genetic diversity of T. orientalis. Furthermore the risk factors for the occurrence of the above protozoan parasites in beef cattle from northern and northeastern parts of Thailand were assessed. A total of 329 blood samples were collected from beef cattle in 6 provinces. The study revealed that T. orientalis was the most prevalent (30.1%) parasite in beef cattle followed by B. bigemina (13.1%) and B. bovis (5.5%). Overall, 78.7% of the cattle screened were infected with at least one of the above parasites. Co-infection with Babesia spp. and T. orientalis was 30.1%. B. bigemina and T. orientalis were the most prevalent (15.1%) co-infection although triple infection with the three parasites was observed in 3.0% of the samples. Sequencing analysis revealed that B. bigemina RAP1 gene and B. bovis SBP2 gene were conserved among the parasites from different cattle samples. Phylogenetic analysis showed that the T. orientalis MPSP gene from parasites isolated from cattle in north and northeast Thailand was classified into types 5 and 7 as reported previously. Lack of tick control program was the universal risk factor of the occurrence of Babesia spp. and T. orientalis infection in beef cattle in northern and northeastern Thailand. We therefore recommend training of farmers on appropriate tick control strategies and further research on potential vectors for T. orientalis and elucidate the effect of co-infection with Babesia spp. on the pathogenicity of T. orientalis infection on beef in northern and northeastern Thailand.

Osteocalcin and bone-specific alkaline phosphatase in Asian elephants (Elephas maximus) at different ages.

Bone turnover markers could offer a potential alternative means for the early diagnosis of metabolic bone disease in young growing elephants although the baseline of bone turnover markers in elephant is not well established. The aim of this study was to determine any relationship between the age of captive Asian elephants (Elephas maximus) and markers of bone formation. Serum samples from 24 female Asian elephants were collected to evaluate levels of two bone formation markers, namely, osteocalcin (OC) and bone-specific alkaline phosphatase (BAP). Both intact and N-terminal midfragment OC and BAP were negatively correlated with age. The findings demonstrate that younger elephants have a higher rate of bone turnover than older elephants. Use of these and additional bone markers could lead to the establishment of validated protocols for the monitoring of bone disease in elephants.

Clinical history and hematological findings among canines with monocytic ehrlichiosis.

Canine monocytic ehrlichiosis is a tick borne disease caused by Ehrlichia canis, an obligate intracellular rickettsial organism belonging to the family Anaplasmataceae. Canine ehrlichiosis causes hemaotological changes among infected animals which could be used as a potential predictor for diagnosing canine monocytic ehrlichiosis (CME). Ninety-four blood samples were obtained from canines that either presented for a routine health check-up or for clinical illness. A history, physical and laboratory test were conducted on each animal. All samples were examined for E. canis using a 16S rDNA polymerase chain reaction (PCR) amplification to confirm CME infection. Thirty-six of the samples were positive for E. canis using PCR and the rest were negative. The Mann-Whitney and chi-square test were used to compare the differences between the PCR-positive and negative animals. PCR-positive animals had a higher mean body temperature than PCR-negative animals. The following were significantly lower in PCR-positive animals: white blood cell count, eosinophil count, red blood cell count, hemoglobin, hematocrit, platelet count, and the random distribution of width (RDW) of the red blood cells. We evaluated complete blood cell count findings to determine factors associated with CME using multivariable logistic regression analysis and found thrombocytopenia was significantly associated with CME (OR = 0.085; 95% CI: 0.78-0.92, p < 0.001). For every decrease in the platelet count of 10,000 there was a 15% increase in the likelihood of having CME.

Associations among serum N-terminal procollagen type III concentration, urinary aldosterone-to-creatinine ratio, and ventricular remodeling in dogs with myxomatous mitral valve disease.

OBJECTIVE: To assess relationships among serum N-terminal procollagen type III concentration, urinary aldosterone-to-creatinine concentration ratio (UAC), and clinical variables in dogs with myxomatous mitral valve disease (MMVD) and healthy dogs. ANIMALS: 162 dogs with MMVD and 24 healthy control dogs of comparable age and body weight. PROCEDURES: Blood and urine samples were collected from each dog. Dogs with MMVD underwent echocardiography and ECG. Ventricular diameter measurements were normalized for body weight. Serum N-terminal procollagen type III and urinary aldosterone concentrations were measured via radioimmunoassay. Each dog was examined on 1 to 3 occasions. Examinations were repeated at approximately 6-month intervals. RESULTS: Serum N-terminal procollagen type III concentration decreased with increasing severity of MMVD and was negatively associated with age and left ventricular end-diastolic and end-systolic diameters. The UAC increased with prior percentage change in left ventricular end-diastolic diameter per month, subsequent percentage change in left ventricular end-systolic diameter per month, and treatment with diuretics and was negatively associated with age. Both UAC and serum N-terminal procollagen type III concentration were higher in Cavalier King Charles Spaniels than in other breeds when other measured variables were controlled for. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs with MMVD, echocardiographic indicators of left ventricular remodeling appeared to be associated with a decrease in serum concentration of a marker of collagen type III turnover and an increase in urinary aldosterone concentration.

Identification of Ehrlichia spp in canines in Thailand.

Canine ehrlichiosis is an endemic parasitic disease widely found in Thailand. The causative microorganism is tick-borne Ehrlichia spp, an obligate intracellular rickettsia residing in leukocytes. Ehrlichia spp in morulae-positive canine blood samples were identified using polymerase chain reaction amplification and direct sequencing of Ehrlichia spp. 16S rDNA 396 bp fragment and 36 of 59 were positive for E. canis. E. chaffeensis and E. ewingii were not detected. Sequencing alignment and phylogenetic analysis showed that 16S rDNA sequences of E. canis strains are 99.1-100% identical among E. canis strains from different countries worldwide. Further studies are required in order to determine new target sequence for genotyping of E. canis strains in the dog population in Thailand.

Selected echocardiographic variables change more rapidly in dogs that die from myxomatous mitral valve disease.

OBJECTIVES: To determine if echocardiographic measurements change at a greater rate in dogs with myxomatous mitral valve disease (MMVD) that die of cardiac mortality. ANIMALS: Client-owned dogs (n = 242) with MMVD of varying severity were recruited from first opinion private practice. Only dogs which died during the study period (n = 102) were included in statistical analyses. METHODS: Prospective cohort study comparing the rate of change of echocardiographic variables between dogs that experienced cardiac mortality and those that experienced non-cardiac mortality. Measurements were repeated approximately every 6 months and repeated measures linear models were constructed to estimate the rate of change of each variable over time. RESULTS: Left ventricular (LV) end-diastolic diameter, normalized for body weight (LVEDDN) increased over time in both mortality groups. LV end-systolic diameter, normalized for body weight (LVESDN), LV end-diastolic diameter to LV free wall thickness in diastole (LVEDD/LVFWd) ratio, E wave velocity, E- to A-wave velocity ratio and left atrial to aortic root diameter ratio all increased over time in the cardiac mortality group, but did not change in the non-cardiac mortality group. MR velocity decreased over time in the cardiac mortality group but did not change in the non-cardiac mortality group. Tricuspid regurgitation jet velocity increased over time in both mortality groups. A wave velocity and fractional shortening did not change over time in either mortality group. CONCLUSIONS: Serial echocardiographic examination every 6-12 months is useful to identify dogs with progressive MMVD that are at increased risk of cardiac mortality.

Ultrasonographic measurement of flow-mediated vasodilation in dogs with chronic valvular disease.

OBJECTIVES: To measure flow-mediated vasodilation (FMD) in healthy dogs and in client-owned dogs with chronic valvular disease (CVD) and to investigate possible correlations between markers of CVD severity and FMD. ANIMALS: Twelve dogs with CVD and 11 healthy weight-matched dogs. METHODS: Brachial artery FMD following 5 min inflation of a cuff around the antebrachium was measured in 12 dogs with CVD and 11 healthy weight-matched dogs. Measurements were also obtained in the healthy dogs 5 min after cuff placement but without inflation ('sham cuff placement'). Dogs with CVD underwent echocardiography to confirm and characterize their disease. RESULTS: In healthy dogs (median age 4 [2-6] years), median FMD was 7.7% versus 3.4% with sham cuff placement (P = 0.003). In dogs with CVD (median age 8 [4-16] years) median FMD was 5.5% versus 7.7% in healthy dogs (P = 0.131). FMD showed an inverse correlation with left ventricular end-diastolic diameter normalized for body weight (r = -0.76, P = 0.0043). CONCLUSIONS: Brachial FMD in dogs with early CVD inversely correlates with severity of left ventricular remodelling.