New rapid test for plague

A new rapid diagnostic test has been developed with the aim of controlling plague in endemic countries. Plague is often fatal without prompt diagnosis and appropriate treatment. Late diagnosis is one of the major causes of human death and spread of the disease, since it limits the effectiveness of control measures. Researchers from Institut Pasteur de Madagascar developed and assessed a rapid diagnostic test for plague. The test uses monoclonal antibodies to the F1 antigen of Yersinia pestis, the causative agent of plague. Sensitivity and specificity were assessed with a range of bacterial cultures and clinical samples, and compared with findings from other available tests for plague. Samples from patients thought to have plague were tested with the RDT in the laboratory and by health workers in 26 pilot sites in Madagascar. The sensitivity and specificity of these tests were both 100%. RDT detected more positive clinical specimens than bacteriological methods or ELISA. The agreement rate between tests done at remote centres and in the laboratory was 89·8%. With the combination of bacteriological methods and ELISA as reference standard, the positive and negative predictive values of the RDT were 90·6% and 86·7%, respectively. The new test is a specific, sensitive and reliable test that can be easily done by health workers at the patient's bedside, for the rapid diagnosis of plague. This test will be of key importance for the control of plague in developing countries.