Allantoic luid was harvested after death of embryo or on 3 dpi and tested for the presence of influenza A virus by haemagglutination (HA) test as per the OIE (11) using 0.5 per cent chicken red blood cell (RBC) suspension.
Mutations in the corresponding biosynthesis genes (ica operon) lead to a pleiotropic phenotype; the cells are biofilm and haemagglutination negative, less virulent and less adhesive on hydrophilic surfaces.
Because it is possible to differentiate between the individual classes of immunoglobulins by enzyme immunoassay, more precise statement about the status of patients can be made with these tests, than other tests like the Haemagglutination Inhibition assay or Complement fixation test.
Detection of a fourfold or greater rise in antibodies specific to JE virus as measured by haemagglutination inhibition (Hl) or plaque reduction neutralization assay (PRNT) in serum collected during the acute and convalescent phase of illness.
Serological tests include haemagglutination inhibition test, complement fixation test (CFT ), enzyme-linked immunosorbent assay (ELISA), antigen capture ELISA and neutralisation test, while molecular test used for diagnosis is RT-PCR.1 For the detection and isolation of virus, mosquito cell culture has been preferably used but due to low sensitivity it has been combined with RT-PCR for the swift diagnosis of dengue.