These include 1) a complement-fixation
test that is relatively insensitive because in 25% of patients complement-fixing antibodies are not detected and in 75% of patients these antibodies appear late after infection; 2) a seroneutralization assay for detection neutralizing antibodies that appear 14-21 days after onset of disease; 3) an immunofluorescence assay that uses CTFV-infected BHK-21 or Vero cells and is an easy and rapid test for detecting anti-CTFV antibodies; and 4) an enzyme-linked immunosorbent assay (ELISA) for immunoglobulin M (IgM) and IgG that appear concurrently or a few days after neutralizing antibodies (peak 30-40 days after infection), However, IgM titers decrease sharply after day 45.
Immunodiffusion and complement-fixation
serologic tests were performed at the Centers for Disease Control and Prevention (CDC).
burnetii in acute- and convalescent-phase serum samples by complement-fixation
test (CFT) or indirect immunofluorescence assay (IF).
Seven virus isolates were obtained and identified by complement-fixation
and neutralization tests.