Multiple RNA splicing and the presence of cryptic RNA splice donor and acceptor sites may contribute to low expression levels and poor immunogenicity of potential DNA vaccines containing the env gene of equine infectious anemia virus (EIAV).

The env gene is an excellent candidate for inclusion in any DNA-based vaccine approach against equine infectious anemia virus (EIAV). Unfortunately, this gene is subjected to mutational pressure in E. coli resulting in the introduction of stop codons at the 5' terminus unless it is molecularly cloned using very-low-copy-number plasmid vectors.

Derivation and characterization of a live attenuated equine influenza vaccine virus.

Objective: To develop and characterize a cold-adapted live attenuated equine-2 influenza virus effective as an intranasal vaccine.

Animals: 8 ponies approximately 18 months of age.

Procedures: A wild-type equine-2 virus, A/Equine/Kentucky/1/91 (H3N8), was serially passaged in embryonated chicken eggs at temperatures gradually reduced in a stepwise manner from 34 C to 30 C to 28 C to 26 C.

Safety, efficacy, and immunogenicity of a modified-live equine influenza virus vaccine in ponies after induction of exercise-induced immunosuppression.

Objective: To determine safety, efficacy, and immunogenicity of an intranasal cold-adapted modified-live equine influenza virus vaccine administered to ponies following induction of exercise-induced immunosuppression.

Design: Prospective study.

Animals: Fifteen 9- to 15-month old ponies that had not had influenza.

Transcutaneous immunization of domestic animals: opportunities and challenges.

Transcutaneous immunization (TCI), the topical application of antigen and adjuvant directly onto intact skin, can safely and effectively elicit systemic immune responses in mice and humans against a variety of antigens. This novel method of vaccine delivery has the potential to provide a safe and convenient method by which vaccines may be delivered to elicit protective immunity in domestic animals. To date, however, immune responses induced by TCI in companion and production animals has not been reported.

Tissue sites of persistent infection and active replication of equine infectious anemia virus during acute disease and asymptomatic infection in experimentally infected equids.

Equine infectious anemia virus (EIAV) infection of horses is characterized by recurring cycles of disease and viremia that typically progress to an inapparent infection in which clinical symptoms are absent as host immune responses maintain control of virus replication indefinitely. The dynamics of EIAV viremia and its association with disease cycles have been well characterized, but there has been to date no comprehensive quantitative analyses of the specific tissue sites of EIAV infection and replication in experimentally infected equids during acute disease episodes and during asymptomatic infections in long-term inapparent carriers. To characterize the in vivo site(s) of viral infection and replication, we developed a quantitative competitive PCR assay capable of detecting 10 copies of viral DNA and a quantitative competitive reverse transcription-PCR assay with a sensitivity of about 30 copies of viral singly spliced mRNA.