Experimentally induced Bartonella henselae infections followed by challenge exposure and antimicrobial therapy in cats.

OBJECTIVES: To elucidate kinetics of Bartonella henselae bacteremia and IgG response, evaluate antibiotic therapy, and investigate challenge exposure in cats. ANIMALS: Specific-pathogen-free cats. PROCEDURE: Cats were inoculated with B henselae or B quintana and monitored. Convalescent cats were challenge exposed with B henselae. Amoxicillin, enrofloxacin, erythromycin, and tetracycline HCl were evaluated for effect on B henselae bacteremia. RESULTS: Cats developed B henselae bacteremia within 1 week; bacteremia persisted for longer than 2 months before subsiding spontaneously. IgG antibody titer developed shortly after onset of bacteremia; antibody co-existed with bacteremia for several weeks and remained detectable after bacteremia subsided. Cats inoculated with B quintana remained abacteremic. On challenge exposure to B henselae, cats previously infected with B henselae remained abacteremic; cats previously inoculated with B quintana supported B henselae infection. Tetracycline HCl and erythromycin depressed B henselae bacteremia; however, duration of bacteremia remained similar to that in untreated cats. Obvious signs of illness were not observed. CONCLUSIONS: Long-duration, high-titer B henselae infections were highly reproducible in cats. Convalescent cats were immune to reinfection. B quintana-inoculated cats did not have evidence of infection and were susceptible to B henselae challenge exposure. Antibiotic therapy was incompletely efficacious in terminating cat bacteremia. CLINICAL RELEVANCE: A cat with an inapparent B henselae infection must provisionally be regarded as a possible reservoir for infection for a minimum of 2 to 3 months. Convalescent cats are resistant to reinfection. Usual antibiotic therapy was not completely efficacious. Measurement of IgG antibody can be used to detect past or current infection.

Immunogenicity, efficacy and safety of an oral rabies vaccine (SAG-2) in dogs.

A study of immunogenicity and efficacy of Street Alabama Gif (SAG-2) attenuated rabies virus vaccine in laboratory beagles was conducted. Four groups of ten dogs each received either 1.0 ml of SAG-2 orally on the tongue or 1.5 ml in baits. On day 180 postvaccination, all dogs were challenged with a street rabies virus. The antibody response in groups that received the vaccine directly on the tongue was higher than in those vaccinated with baits, but the difference between groups was not statistically significant. All vaccinated dogs survived, whereas 80% of controls died of rabies. Our findings demonstrate that the SAG-2 is a safe and effective vaccine for oral immunization of canines.