title: Haptoglobin and fibrinogen concentrations and leukocyte counts in the clinical investigation of caseous lymphadenitis in sheep.
abstract: BACKGROUND
  Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis (CLA), a disease that affects small ruminants and is responsible for economic losses, including condemnation of carcasses and damaged hides.
  
  
  OBJECTIVE
  The goal of this study was to determine if serum haptoglobin and plasma fibrinogen concentrations and peripheral blood leukocyte counts are biologic markers of CLA in sheep.
  
  
  METHODS
  Blood from 38 clinically healthy Santa-Inês ewes selected and segregated from a commercial flock of 2500 sheep in an area endemic for C. pseudotuberculosis was collected every 30 days for 6 months. An indirect ELISA was used to detect IgM and IgG antibodies against C. pseudotuberculosis. Serum haptoglobin concentration was measured using a hemoglobin-binding assay and plasma fibrinogen concentration by refractometry following heat precipitation. Total leukocyte counts were determined using a hemocytometer, and differential leukocyte counts were performed on smears of peripheral blood.
  
  
  RESULTS
  Twenty-one sheep were seropositive at the start of the study; 15 became seropositive during the study. Only 2 sheep were seronegative at the conclusion of the study. Haptoglobin and fibrinogen concentrations and WBC counts were not significantly different for seropositive and seronegative animals. Nine sheep, 5 that were seropositive positive at the start and 4 that became seropositive during the study period, developed abscesses in peripheral lymph nodes. There were 15 animals that became seropositive during the study, and their values did not differ significantly among the 3 phases--seronegative, acute (IgM+/IgG±), and chronic (IgM-/IgG+)--of infection. However, 11 of these sheep did not develop peripheral abscesses and had significantly higher haptoglobin concentrations and lower monocyte counts during the acute phase of the disease than did the 4 sheep that later developed abscesses.
  
  
  CONCLUSIONS
  Serum haptoglobin concentration and monocyte counts may be potential markers for progression of CLA in sheep.
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.|Veterinary Clinical Pathology Laboratory.
authors.forename: Bruno L
authors.initials: BL
authors.lastname: Bastos
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.
authors.forename: Roberto
authors.initials: R
authors.lastname: Meyer
authors.affiliation: Veterinary Clinical Pathology Laboratory.
authors.forename: José E
authors.initials: JE
authors.lastname: Guimarães
authors.affiliation: Veterinary Clinical Pathology Laboratory.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Ayres
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Guedes
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.
authors.forename: Lilia F
authors.initials: LF
authors.lastname: Moura-Costa
authors.affiliation: Veterinary Clinical Pathology Laboratory.
authors.forename: Uiara S
authors.initials: US
authors.lastname: de Burghgrave
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.
authors.forename: Ludmilla
authors.initials: L
authors.lastname: Sena
authors.affiliation: Molecular and Cellular Genetics Laboratory, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Vasco
authors.initials: V
authors.lastname: Azevedo
authors.affiliation: Immunology and Molecular Biology Laboratory, Health Sciences Institute.
authors.forename: Ricardo W
authors.initials: RW
authors.lastname: Portela
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis*; D001938:Brazil / Q000453:epidemiology; D003354:Corynebacterium Infections / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D016925:Corynebacterium pseudotuberculosis / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006242:Haptoglobins / Q000032:analysis; D007958:Leukocyte Count / Q000662:veterinary; D007962:Leukocytes / Q000166:cytology*; D008199:Lymphadenitis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D015415:Biomarkers; D006242:Haptoglobins; D005340:Fibrinogen