Serologic Studies on Subclinical Melioidosis

Abstract

Of 337 sera from apparently healthy adult Thai males, 8.3% gave positive complement fixation reactions for melioidosis. Only 1 of 78 sera from Thai females was positive. None of 138 sera from a control group in the United States was positive with this test. Of 405 Thai sera, 29.1% gave positive hemagglutination reactions for melioidosis with a purified polysaccharide antigen. Only 7.4% of the control group in the United States gave positive reactions with this test. The protein antigen used in similar hemagglutination tests was not suitable for diagnostic purposes because positive reactions, apparently not referable to melioidosis, were encountered with this antigen in some sera. The combined results of the serologic survey indicated that subclinical or unrecognized mild melioidosis was probably rather prevalent in Thailand and that the 95% mortality figure for melioidosis as reported in the literature was not tenable. The significance of the serologic results in relation to the epidemiology of melioidosis is discussed.