Técnicas para el diagnóstico de laboratorio del tifo y otras rickettsiasis

Abstract

On the occasion of the first Inter-American Typhus Meeting held in Mexico on October 1945, the Pan American Typhus Commission discussed the methods for the diagnosis of typhus and advised that a preliminary test should be recommended using Castaneda's blue X-19 antigen and after this preliminary test the serum be sent to special laboratories for a differential test by complement fixation, using murine and classic rickettsial suspensions as antigens. Because of the necessity of uniform results, the X-19 antigen has to be prepared and delivered by the Typhus Laboratory of Mexico, until reliable laboratories take over the production. In case that it is produced elsewhere, samples of each lot must be sent to Dr. M. Ruiz Castaneda who shall inform periodically about the conditions of the antigen in order to discontinue its use in case of deterioration

The OX-19 antigen is a suspension containing approximately 100 billion organisms per ml. which are stained in blue to facilitate the observation of positive tests in mixtures of blood and antigen. It is titrated in order to produce a visible agglutination only when the agglutinin content of the blood is above 1:100. Non-significant tests are, therefore, ruled out

The preliminary test is usually negative until the 5th or 6th day of the disease and becomes positive from the 5th to the 7th day on. A positive test after one or more negatives is of ...(AU)

Traducido del inglés de la obra "Diagnostic Procedures & reagents," 2a. ed., pp. 232-246 por la OPS