A new diagnostic strategy was assessed for the routine diagnosis of intestinal parasites in returning travellers and immigrants. Over a period 13 months, unpreserved stool samples, patient characteristics and clinical data were collected from those attending a travel clinic. Stool samples were analyzed on daily basis by microscopic examination and antigen detection (i.e. care as usual), and compared with a weekly performed multiplex real-time PCR analysis on Entamoeba histolytica, Giardia lamblia, Cryptosporidium and Strongyloides stercoralis. Microscopy and antigen assays of 2591 stool samples showed E. histolytica, G. lamblia, Cryptosporidium and S. stercoralis in 0.3%, 4.7%, 0.5%, and 0.1% of the cases, respectively. These detection rates were increased using real-time PCR to 0.5%, 6.0%, 1.3% and 0.8%, respectively. Prevalence of 10 additional pathogenic parasite species identified with microscopy was 0.5% at most. A pre-selective decision tree based on travel history or gastro-intestinal complaints could not be made. With increased detection rates at a lower workload, and the potential to extend with additional parasite targets combined with fully automated DNA isolation, the molecular high throughput screening could eventually replace microscopy to a large extend.
Robert ten Hove, Marjan van Esbroeck, Tony Vervoort, Jef van den Ende, Lisette van Lieshout, Jaco J. Verweij. European Journal of Clinical Microbiology and Infectious Diseases, 2009.