RESUMEN
A disease named locally as churrío or churrido equino (i.e., equine scours) has occurred for at least 100 years in Uruguay and southern Brazil in farms along both shores of the Merín lake. This report describes cases of churrido equino and provides serologic, pathologic, and DNA-based evidence indicating that the disease is in fact equine monocytic ehrlichiosis (Potomac horse fever). Results of an epidemiological investigation conducted on an endemic farm are also presented. Clinical signs in 12 horses were fever, depression, diarrhea, dehydration, and sometimes colic and distal hind limb edema. Postmortem findings of 3 horses were of acute enterocolitis. Inclusion bodies containing ehrlichial organisms were found in the cytoplasm of macrophages of the large colon of 1 horse. Eleven of the 12 horses were serologically positive to Ehrlichia risticii (indirect fluorescent antibody assay) and, of 3 paired samples, 2 showed seroconversion. Ehrlichia risticii DNA was identified by a nested polymerase chain reaction in peripheral blood of an affected horse. A healthy horse inoculated with peripheral blood from an affected horse developed the disease and antibodies to E. risticii. The disease had a peak incidence in March (summer) and was statistically associated with a marshy ecosystem near the Merín lake, where large numbers of Pomacea spp. (Ampullariidae) snails were found. Incidence density was almost 8 times higher in nonnative horses than in native horses. It was concluded that the previous diarrheic disease of horses known in Uruguay and southern Brazil as churrido equino is equine monocytic ehrlichiosis.
Asunto(s)
Brotes de Enfermedades/veterinaria , Ehrlichia/genética , Ehrlichiosis/veterinaria , Enfermedades de los Caballos/patología , Animales , Brasil/epidemiología , ADN Bacteriano/análisis , Diarrea/etiología , Diarrea/veterinaria , Ecosistema , Ehrlichia/patogenicidad , Ehrlichiosis/genética , Ehrlichiosis/patología , Enterocolitis/etiología , Enterocolitis/veterinaria , Femenino , Enfermedades de los Caballos/genética , Caballos , Masculino , Reacción en Cadena de la Polimerasa , Estaciones del Año , Caracoles , Uruguay/epidemiologíaRESUMEN
In 48 patients who had neurosensory hypoacusia and whose main complaint was tinnitus, a 1% pilocarpine solution or a 2% carbachol Isopto solution was placed in the tympanic cavity by means of a No. 26 pencil-tipped lumbar puncture needle through the front quadrant of the eardrum. Patients were chosen without regard for age, gender, or topographical damage of the acoustic pathway. Evaluation of the drug's effect was performed audiometrically by masking with the minimum intensity of the pure sound or narrow band that most closely resembled the patients' own noises. The results of this medical therapy were positive and ranged from complete annulment to attenuation of the tinnitus, which was confirmed by audiometric masking 30 minutes after the intratympanic injection. These positive results reached 50% and would have been higher if the several cases submitted by accident insurance companies and cases of presbyacusia were discarded. The unsatisfactory element of the study was the short-term effect of the therapy, which usually lasted no more than 12-72 hours. Tinnitus reappeared in all patients at its original intensity. The best results involved the use of carbachol as compared with pilocarpine. The decision to replace pilocarpine with carbachol was based on the idea that the inhibitory cholinergic efferent pathways are damaged before the afferent pathways. The use of pilocarpine depends on efficient cholinergic functioning, as its activity is as an indirect agonist (i.e., to annul the cholinesterase enzyme).