ABSTRACT
Rickettsia felis is a human pathogen transmitted by the cat flea, Ctenocephalides felis (Bouché) (str. LSU), as well as an obligate symbiont of the parthenogenic booklouse Liposcelis bostrychophila (Badonnel) (str. LSU-Lb). The influence of genetic variability in these two strains of R. felis on host specialization and fitness and possible resulting differences on infection and transmission kinetics in C. felis is unknown. Utilizing an artificial host system, cat fleas were exposed to a R. felis str. LSU-Lb-infected bloodmeal and monitored for infection at 7-d intervals for 28 d. Quantitative real-time PCR was used to determine rickettsial load and infection density in newly exposed cat fleas, and transmission frequency between cat fleas. The effect of persistent R. felis infection on cat flea F1 progeny was also assessed. At 7 d postexposure 76.7% of the cat fleas successfully acquired R. felis str. LSU-Lb. In R. felis str. LSU-Lb-exposed cat fleas, the mean infection load (6.15 × 106), infection density (0.76), and infection prevalence (91/114) were significantly greater than R. felis str. LSU infection load (3.09 × 106), infection density (0.68), and infection prevalence (76/113). A persistent R. felis str. LSU-Lb infection was detected for 28 d in adult cat fleas but neither female:male ratio distortion nor vertical transmission was observed in F1 progeny. While infection kinetics differed, with higher intensity associated with R. felis str. LSU-Lb, no distinct phenotype was observed in the F1 progeny.
Subject(s)
Cat Diseases/epidemiology , Cat Diseases/transmission , Infectious Disease Transmission, Vertical/veterinary , Rickettsia Infections/veterinary , Rickettsia felis/physiology , Siphonaptera/microbiology , Siphonaptera/physiology , Animals , Bacterial Load , Cat Diseases/microbiology , Cats , Female , Genetic Fitness , Host Specificity , Male , Prevalence , Rickettsia Infections/epidemiology , Rickettsia Infections/microbiology , Rickettsia Infections/transmission , Rickettsia felis/geneticsABSTRACT
This paper provides a 50-year overview of research and clinical advances in AAVMC member colleges in four representative fields of veterinary medicine: oncology, vaccine development, production medicine, and public health. Though emphasis is on the progress since the mid-1960s, the salient background and associated personnel in each field are also identified to the extent that their description informs more recent events. Advances in board certification and post-graduate clinical and research educational opportunities are also described.
