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.

Development of multiplex polymerase chain reaction for detection of feline hemotropic mycoplasma in blood and tissue specimens

A multiplex polymerase chain reaction (PCR) was developed for the detection of feline hemotropic mycoplasmas which simultaneously differentiates infections of Mycoplasma haemofelis (Mhf), Candidatus Mycoplasma haemominutum (CMhm) and Candidatus Mycoplasma turicensis (CMtc) in feline blood and spleen. These organisms are responsible for the cause of various pathogenicity of feline infectious anemia. These infections are difficult to be detected by microscopic examination, the most commonly used method for general laboratory diagnoses. Specific primers were designed by selected consensus 16S rDNA sequences of three distinct species. The multiplex PCR assay developed in this study was sensitive and specific with detection limit 100 copies/microl DNA of Mhf and CMhm and 10 copies/microl DNA of CMtc. No amplicons could be amplified for other blood parasites or bacterial pathogens. This multiplex PCR will allow studies of pathogenicity and the monitoring of clinical treatment.

Development of multiplex polymerase chain reaction for detection of Ehrlichia canis, Babesia spp and Hepatozoon canis in canine blood

A multiplex polymerase chain reaction (PCR) has been developed for simultaneous detection of canine blood parasites, Ehrlichia canis, Babesia spp and Hepatozoon canis, from blood samples in a single reaction. The multiplex PCR primers were specific to E. canis VirB9, Babesia spp 16S rRNA and H. canis 16S rRNA genes. Specificity of the amplicons was confirmed by DNA sequencing. The assay was evaluated using normal canine and infected blood samples, which were detected by microscopic examination. This multiplex PCR offers scope for simultaneous detection of three important canine blood parasites and should be valuable in monitoring parasite infections in dogs and ticks.