Investigations of Fluorescent Treponemal Antibodies in the Non-Infected Population in Areas of Endemic Syphilis in Bosnia

Abstract

This study is contemplating to explain the benign course of endemic treponematoses particularly endemic syphilis in Bosnia taking in consideration the specific immunological condition in the population of endemic areas. In rural areas where endemic syphilis is occurring, because of low hygienic habits, the population is in the rule repeatedly exposed especially within the diseased families, to infection supposedly by small number of treponemes. This may originate an antigenic action without causing any apparent disease and the production of a certain number of specific antibodies prior to a massive infection which under such immunological condition could induce an attenuated benign course of the disease.

The investigations carried out relate to antibodies which can be demonstrated by the quantitative fluorescent treponemal antibody test in low dilutions (below those of diagnostic value 1 : 200). This examination has been performed in healthy population (i. e. in people with negative reagin tests and negative FTA200 test and without any other evidence of syphilis) from highly infected regions of endemic syphilis and from areas where endemic syphilis did not occure.

In this respect 663 sera were tested with following results (tab. 1, 2. and 3):

1) The titters of fluorescent antibodies were in general higher in the healthy population living in infected regions than in non-infected.

2) The amount of antibodies which could be demonstrated by the quantitative fluorescent treponemal antibody test 1 :10, 1 :50, 1 : 100 and 1 : 150 (positive sera in higher dilution are considered as diagnostic for syphilis and excluded) have been found to stay in correlation with the degree of exposition to infection of endemic syphilis. Statistically significant higher levels of FTA antibodies were found in healthy persons living within infected population than from those living in non-infected region.

3) The obtained results support the hypothesis that the preinfected immunological state induced by antigenic action of small number of treponemes might be considered responsible for the benign course of endemic treponematoses.