Transmission of feline calicivirus via the cat flea (Ctenocephalides felis).

In this study, a possible role of the cat flea (Ctenocephalides felis) in transmitting feline calicivirus (FCV) was examined. Fleas were fed via artificial membranes with FCV-spiked bovine blood, free of anti-FCV antibodies. Flea feces were collected daily for 10 days and incubated at room temperature. Infectivity of the feces was tested in vitro using Crandell-Reese Feline Kidney (CRFK) cells. FCV remained infectious for 8 days. These flea feces were also used to oronasally inoculate four specific pathogen-free (SPF) kittens. All kittens were successfully infected as demonstrated by virus isolation from pharyngeal swabs and seroconversion. Two of the cats showed, in addition, clinical signs. Besides the infection of cats with flea feces containing FCV, four SPF kittens were exposed to fleas that were fed with FCV-spiked bovine blood. One of the kittens was successfully infected via this route as demonstrated by virus isolation from pharyngeal swabs and virus isolation. The results of this study show that fleas can spread infectious virus through their feces or by stitch and must be considered a source of infection for uninfected cats.

Protective immunity against pasteurellosis in cattle, induced by Pasteurella haemolytica ghosts.

Pasteurella haemolytica is a cattle pathogen of significant economic impact. An effective vaccine against bovine pneumonic pasteurellosis is therefore of high importance. Apart from economic concerns, pasteurellosis caused by P. haemolytica is a serious disease leading to death in cattle if it remains untreated. In this study P. haemolytica-ghosts are presented as a promising vaccine candidate in cattle. To obtain sufficient vaccination material a fermentation protocol for P. haemolytica-ghost production was established. With the obtained experimental P. haemolytica-ghost vaccine, cattle immunization studies were performed based on a Pasteurella cattle challenge model developed specifically for vaccine validation. It was shown that protective immunization of cattle against homologous challenge was induced by adjuvanted P. haemolytica-ghosts. The level of protection was similar to a commercially available vaccine.