title: Establishment and characterization of a low-dose Mycoplasma haemofelis infection model.
abstract: Hemotropic mycoplasma are small, cell-wall-free bacteria that can infect various mammalian species, including humans. They cannot be cultured in vitro; therefore, animal models play an important role, e.g. for pathogenesis studies. Mycoplasma haemofelis (Mhf) is the most pathogenic of the three feline hemotropic mycoplasma species; it is known to induce severe hemolytic anemia in infected cats. The aims of this study were to establish and characterize a low-dose Mhf transmission model. Five specified pathogen-free cats were subcutaneously exposed to 1000 copies of Mhf per cat corresponding to 0.05 μL of infectious blood with 2×10(7) copies/mL as determined by real-time PCR. All cats became PCR-positive within 34 days post-exposure and reached a maximum blood Mhf load of 10(9) copies/mL, similar to previously reported high-dose infections. In a selected sample of modified Wright-stained blood smears, small epicellular coccoid structures on the surface of the red blood cells were identified by light microscopy. Additionally, using an Mhf rDnaK ELISA, seroconversion was demonstrated in all cats within 4-5 weeks after Mhf exposure. Four out of five cats developed anemia. While three cats showed only mild clinical signs of hemoplasmosis, one cat developed severe anemia and required antibiotic treatment. Our study demonstrated that minimal contact with Mhf infectious blood was sufficient for transmission of the infection and the induction of hemoplasmosis. This low-dose Mhf infection might more accurately mirror the natural route of infection, i.e., by arthropod vectors or aggressive interaction among cats. We therefore recommend this protocol for use in future animal model studies.
authors.affiliation: Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland. Electronic address: jbaumann@vetclinics.uzh.ch.
authors.forename: Julia
authors.initials: J
authors.lastname: Baumann
authors.forename: Marilisa
authors.initials: M
authors.lastname: Novacco
authors.forename: Barbara
authors.initials: B
authors.lastname: Riond
authors.forename: Felicitas S
authors.initials: FS
authors.lastname: Boretti
authors.forename: Regina
authors.initials: R
authors.lastname: Hofmann-Lehmann
mesh_terms: D000740:Anemia / Q000209:etiology / Q000662:veterinary; D000818:Animals; D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial / Q000097:blood; D002371:Cat Diseases / Q000175:diagnosis / Q000276:immunology / Q000635:transmission*; D002415:Cats; D004269:DNA, Bacterial / Q000097:blood; D004195:Disease Models, Animal; D056724:Immunity, Humoral / Q000276:immunology; D008297:Male; D009174:Mycoplasma / Q000235:genetics; D009175:Mycoplasma Infections / Q000150:complications / Q000276:immunology / Q000635:transmission / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D060888:Real-Time Polymerase Chain Reaction; D012698:Serologic Tests / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms
chemical_list: D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D004269:DNA, Bacterial
keywords: Experimental infection; Humoral immune response; Infection model.; Low-dose infection; Mycoplasma haemofelis; Route of transmission