RESUMEN
Intraerythrocytic Babesia-like trophozoites were seen in postmortem kidney sections of a free-roaming cat in Hong Kong. DNA sequences of the 18S rRNA and mitochondrial cytochrome b genes had only 96.7% and 90.4% nucleotide identity with known Babesia sequences. We propose that this new species be named Babesia hongkongensis.
Asunto(s)
Babesia/clasificación , Babesia/aislamiento & purificación , Babesiosis/veterinaria , Enfermedades de los Gatos/parasitología , Animales , Babesia/genética , Babesiosis/parasitología , Gatos , Análisis por Conglomerados , Citocromos b/genética , ADN Protozoario/química , ADN Protozoario/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Eritrocitos/parasitología , Genes de ARNr , Histocitoquímica , Hong Kong , Riñón/parasitología , Datos de Secuencia Molecular , Filogenia , ARN Protozoario/genética , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADNRESUMEN
The newly described brittle tail syndrome causes weakening and breakage of the tail hair of horses. Extensive mycological and molecular studies showed that a novel fungus Equicapillimyces hongkongensis gen. nov., sp. nov. is the most likely cause of this syndrome. It is a septate branching hyaline mould which grows optimally at 30°C, requires nicotinic acid but is inhibited by cycloheximide, and specifically infects horse hair. Hyphae fill the core of infected hair shafts with short-necked structures resembling ascomata containing banana-shaped septate ascospore-like structures perforating the hair cortex from within. Compared to asymptomatic horses (n=31), horses with clinical signs of the syndrome (n=22) are significantly more likely to have positive E. hongkongensis gen. nov., sp. nov. smear (6.5% vs. 100%), culture (6.5% vs. 72.7%), and PCR (32.3% vs. 100%, P<0.001 for all). No other potential pathogens were found on bacteriological and mycological culture or PCR (for Trichophyton, Microsporum and Epidermophyton). Genotyping of pure E. hongkongensis gen. nov., sp. nov. isolates and their corresponding direct specimens by PCR and sequencing of the 18S rRNA, ITS1-5.8S-ITS2, 28S rRNA, beta-actin, beta-tubulin, and elongation factor 1 alpha showed that they are all identical but unique, and related distantly to fungi mostly in the class Sordariomycetes and the family Ophiostomataceae. Its geographical distribution, environmental or animal reservoirs are still unknown. Besides the ugly appearance of infected horse tails, this fungus may emerge as another equine pathogen if it affects the skin and hoof of horses.
Asunto(s)
Ascomicetos/aislamiento & purificación , Enfermedades de los Caballos/microbiología , Micosis/veterinaria , Actinas/genética , Animales , Ascomicetos/clasificación , Ascomicetos/genética , Secuencia de Bases , Genotipo , Enfermedades de los Caballos/patología , Caballos , Datos de Secuencia Molecular , Micosis/microbiología , Micosis/patología , Filogenia , Reacción en Cadena de la Polimerasa , ARN Ribosómico/genética , Síndrome , Cola (estructura animal) , Tubulina (Proteína)/genéticaRESUMEN
There are no comprehensive studies on the performance of commonly used point-of-care diagnostic enzyme immunoassay for common arthropod-borne canine pathogens. A comparative evaluation of an immunochromatographic test for these infections with a comprehensive polymerase chain reaction (PCR) test panel was performed on 100 pet dogs and 100 stray dogs without obvious clinical symptoms. Of the 162 positive test results from both immunochromatographic test and PCR, there was 85.2% concordance. The 24 discordant results between serology and PCR occurred in tests involving Ehrlichia canis (14) and Anaplasma platys (10), which may be related to the time of infection. No positive cases of borreliosis or rickettsiosis were detected. One important limitation of the immunochromatographic test was its lack of testing for babesiosis and hepatozoonosis. The former is the most prevalent arthropod-borne canine infection in our cohort (41%). Coinfections were found in 19% stray dogs and 6% of pet dogs with both tests (p < 0.01). Seventeen and 8 samples from stray and pet dogs, respectively, were initially positive in the PCR test for Ehrlichia. However, on sequencing of the PCR amplicon, 10 from stray and 2 from pet dogs were found to be Wolbachia sequences instead, with 100% nucleotide identity to the 16S rRNA sequence of Wolbachia endosymbiont of Dirofilaria immitis. The presence of Wolbachia DNAemia (6%) correlated well with the molecular test and immunochromatographic antigen test for D. immitis.