Development of a rapid skin test for the diagnosis of brucellosis

Abstract

Brucellosis is an important infectious disease in human and animals caused by pathogenic species of brucellae. The diagnosis of disease is often made by serological tests, but these tests have false results sometimes. This study has developed a rapid skin test for screening of humoral and allergic immune response to Brucella abortus. Two groups of mice were included in the research; a group immunized intraperitoneally with Brucella abortus bacterin twice at 2 weeks apart and a group kept as control which received PBS by the same route as case groups. Skin tests were performed 15 days after the second immunization by injection of the detector solution (a composition of LPS-free sonicated Brucella antigens, complement and polyelectrolytes) into the abdominal skins of the sensitized animals. After that, the mice were checked for the generation of the inflammatory reaction at the site of injection. The animals were scarified and their skin was evaluated macro- and microscopically for any inflammatory or edematous reactions. An inflammatory reaction was observed in the test group at the first 20 min after SC injection of detector solution. The inflammatory reaction and blue spots of the Evans blue dye were seen at the nearest large veins of the injection site. After 24 h, the inflammation reduced gradually, until 48 h, which skin condition was approximately normal. The gross reactions were proved histopathologically. According to the results, this new rapid skin test shows promise in diagnosing brucellosis and may be useful for diagnosis of different infectious diseases.