Avidity serological tests (avidity enzyme-linked immunosorbent assay [ELISA] and avidity Western blot) were developed and used to differentiate between acute ( @entity281 , reinfection, and recrudescence) and chronic Neospora caninum infection in @entity291 . In addition, the pattern of immunoglobulin G (IgG) avidity maturation against different specific antigens of N. caninum tachyzoites was studied. Sequential serum samples were collected from @entity291 naturally and experimentally infected with N. caninum. Four groups of experimentally infected @entity291 were included in the study and were representative of @entity281 , reinfection, @entity281 , and noninfection. Serum samples were also collected from naturally infected @entity291 classified into nonaborting and aborting @entity291 on the basis of clinical findings and serological profiles, and a third group composed of seronegative @entity291 that seroconverted during the course of the experiment. All samples were tested by avidity ELISA and avidity Western blot. The IgG avidity ELISA allowed the discrimination between primary and @entity281 because all experimentally @entity281 @entity291 showed low avidity indexes at week 4 postinfection (p.i.) compared with the high avidity values found at week 20 postinfection. However, this test did not allow the discrimination of reinfection or recrudescence from @entity281 . Regarding IgG avidity Western blot results, no antigenic markers correlating with acute ( @entity281 , recrudescence, and reinfection) or @entity281 were recognized. However, the 17-kD immunodominant antigen was mostly responsible for high avidity values obtained by avidity ELISA because it was intensively recognized by high-avidity antibodies in all chronically infected animals after @entity1133 treatment.

Use of avidity enzyme-linked immunosorbent assay and avidity Western blot to discriminate between acute and chronic Neospora caninum infection in XXXX .

@entity281 :: ('MESH:D007239', 'Disease') :: ['primary-infection', 'chronic infection', 'primary infection'] @entity291 :: ('9913', 'Species') :: ['cows', 'cattle'] @entity1133 :: ('MESH:D014508', 'Chemical') :: ['urea']
@entity291 :: (9913,Species) :: ['cattle']
