title: Lambs immunized with an inactivated variant of Anaplasma phagocytophilum.
abstract: BACKGROUND
  Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila) is an obligate intracellular bacterium causing the disease tick-borne fever (TBF) in domestic ruminants. An effective vaccine against the infection has been demanded for livestock by sheep farmers and veterinary practitioners for years.
  
  
  RESULTS
  In the present study, we immunized lambs with an inactivated suspension of 1 × 10(8) killed A. phagocytophilum organisms mixed with adjuvant (Montanide ISA 61VG; Seppic). Twelve 9-months-old lambs of the Norwegian White Sheep breed were used. A full two-dose series of immunization was given subcutaneously to six lambs with a 4 week interval between injections. One month after the last immunization, all lambs were challenged with the homologous viable variant of A. phagocytophilum. After challenge, all lambs showed clinical responses for several days, although the immunized lambs reacted with an anamnestic response, i.e. significant reduction in infection rate and a significantly higher antibody titer.
  
  
  CONCLUSIONS
  Immunization with inactivated A. phagocytophilum did not protect lambs TBF.
authors.affiliation: Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Kyrkjevegen 332/334, 4325, Sandnes, Norway. snorre.stuen@nmbu.no.
authors.forename: Snorre
authors.initials: S
authors.lastname: Stuen
authors.affiliation: Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Kyrkjevegen 332/334, 4325, Sandnes, Norway. wenche.okstad@nmbu.no.
authors.forename: Wenche
authors.initials: W
authors.lastname: Okstad
authors.affiliation: Department of Bacteriology, National Veterinary Institute, SE-751 89, Uppsala, Sweden. karin.artursson@sva.se.
authors.forename: Karin
authors.initials: K
authors.lastname: Artursson
authors.affiliation: Department of Infectious Diseases and Pathology, University of Florida, Gainesville, FL, 32611, USA. balkhedery@ufl.edu.
authors.forename: Basima
authors.initials: B
authors.lastname: Al-Khedery
authors.affiliation: Department of Infectious Diseases and Pathology, University of Florida, Gainesville, FL, 32611, USA. barbet@ufl.edu.
authors.forename: Anthony
authors.initials: A
authors.lastname: Barbet
authors.affiliation: Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, PO Box 8144, 0033, Oslo, Norway. erikgeorg.granquist@nmbu.no.
authors.forename: Erik G
authors.initials: EG
authors.lastname: Granquist
mesh_terms: D041081:Anaplasma phagocytophilum / Q000276:immunology*; D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D016873:Ehrlichiosis / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D005260:Female; D007114:Immunization / Q000662:veterinary*; D008297:Male; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000382:microbiology / Q000628:therapy*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D015164:Vaccines, Inactivated