Comparison between PCR and larvae visualization methods for diagnosis of Strongyloides stercoralis out of endemic area: A proposed algorithm

REPETTO SILVIA ANALÍA; RUYBAL PAULA; SOLANA MARIA ELISA; LOPEZ CARLOTA; BERINI CAROLINA ANDREA; ALBA SOTO CATALINA DIRNEY; GONZALEZ CAPPA STELLA MARIS

ACTA TROPICA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 157 p. 169 - 177

0001-706X

Underdiagnosis of chronic infection with the nematode Strongyloides stercoralismay lead to severe disease in the immunosuppressed. Thus, we have set-up aspecific and highly sensitive molecular diagnosis in stool samples. Here, wecompared the accuracy of our polymerase chain reaction (PCR)-based method withthat of conventional diagnostic methods for chronic infection. We also analyzedclinical and epidemiological predictors of infection to propose an algorithm for the diagnosis of strongyloidiasis useful for the clinician. Molecular and goldstandard methods were performed to evaluate a cohort of 237 individuals recruitedin Buenos Aires, Argentina. Subjects were assigned according to theirimmunological status, eosinophilia and/or history of residence in endemic areas. Diagnosis of strongyloidiasis by PCR on the first stool sample was achieved in71/237 (29.9%) individuals whereas only 35/237(27.4%) were positive byconventional methods, requiring up to four serial stool samples at weeklyintervals. Eosinophilia and history of residence in endemic areas have beenrevealed as independent factors as they increase the likelihood of detecting the parasite according to our study population. Our results underscore the usefulnessof robust molecular tools aimed to diagnose chronic S. stercoralis infection.Evidence also highlights the need to survey patients with eosinophilia even when history of an endemic area is absent.