RESUMO
A total samples from 345 healthy blood donors from Loei Province, Northeast Thailand were examined for anti-Toxoplasma gondii antibodies by ELISA. The seroprevalence of the anti-Toxoplasma gondii total Ig, IgG and IgM antibodies was 4.9%, 4.1% and 4.3%, respectively. Overall seropositive rate was 33 out of 345 individuals (9.6%). Among the seropositve cases, 5 (15.2%), 2 (6.1%) and 13 (39.4%) of the samples were determined by using each type of anti-T. gondii total Ig, IgG and IgM antibodies, respectively. The seropositive sera was also determined by combining of anti-T. gondii antibodies (anti-T. gondii total Ig with IgG and anti-T. gondii total Ig with IgM antibodies). These results were 10 (30.3%) and 2 (6.1%) cases, respectively. Only one (3%) sample had all types of anti-T. gondii antibodies. In addition, the frequency distribution curves of ELISA optical densities of anti-T. gondii total Ig, IgG and IgM antibodies in blood donor presented "unimodal" curves. The negative results were found in the age group that less than 20 years old and more than 51. The highest seropositive results were found in two age groups (21-30 and 31-40 years old), and males were significantly higher than female (p < 0.05). These results demonstrated that when using anti-T. gondii total Ig, IgG and IgM antibodies for determining the seroprevalence, the sensitivity was twice that with the anti-T. gondii, total Ig antibody alone.