RESUMEN
Beef cattle from a herd in north Alabama were examined because of an outbreak of nonfatal skin disease characterized by discrete circumscribed areas of inflammation that developed on the skin from the neck to the hips. Areas of inflammation, which tended to be superficial, underwent necrosis and scabbed over. The scabs eventually dropped off leaving discrete, round, whitish, hairless lesions that were 1.2 to 2.5 cm diameter. Because clinical signs were consistent with those expected with pseudo-lumpy skin disease (PLSD) caused by bovine herpesvirus type 2 (BHV-2), samples from 16 representative animals were submitted for BHV-2 testing. All 16 animals were seropositive for BHV-2, but the virus could not be isolated from skin biopsy specimens or buffy coat samples. Results of a polymerase chain reaction assay incorporating primers designed to amplify 2 DNA sequences from BHV-2 were positive for 3 of the 10 cattle, suggesting that skin lesions in these cattle were a result of PLSD. Our findings suggest that PLSD may be more common and widespread in the United States than suggested by the frequency with which BHV-2 has been isolated from cattle with PLSD-like skin lesions.
Asunto(s)
Enfermedades de los Bovinos/diagnóstico , ADN Viral/análisis , Herpes Simple/veterinaria , Herpesvirus Bovino 2/aislamiento & purificación , Reacción en Cadena de la Polimerasa/veterinaria , Alabama/epidemiología , Animales , Secuencia de Bases , Bovinos , Enfermedades de los Bovinos/epidemiología , Brotes de Enfermedades/veterinaria , Femenino , Herpes Simple/diagnóstico , Herpes Simple/epidemiología , Herpesvirus Bovino 2/genética , Dermatosis Nodular Contagiosa/diagnóstico , Masculino , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , Piel/patologíaRESUMEN
A prospective study was performed to determine the serologic response of previously vaccinated horses to revaccination against eastern and western equine encephalomyelitis (EEE and WEE). Horses responded variably to each antigen, and some horses had low or undetectable antibodies 6 months after vaccination. Some horses did not develop increasing titers to EEE or WEE despite recent vaccination. Geometric mean titers peaked 2 weeks after revaccination and were significantly increased from before revaccination. Except for one horse, EEE:WEE titer ratios ranged from 0.25 to 2.0. Regular vaccination against EEE and WEE did not interfere with testing for Saint Louis encephalitis.