Low Sensitivity of Real Time PCRs Targeting Retrotransposon Sequences for the Detection of Schistosoma japonicum Complex DNA in Human Serum

Abstract

While hybridization probe-based real-time PCR assays targeting highly repetitive multi-copy genome sequences for the diagnosis of S. mansoni complex or S. haematobium complex from human serum are well established, reports on the evaluation of respective assays for the identification of S. japonicum complex DNA in human serum are scarce. Here, we assessed the potential use of the retrotransposon sequences SjR2 and SjCHGCS19 from S. japonicum, S. mekongi and S. malayensis for the diagnosis of Asian Schistosoma infections. Based on available S. japonicum sequences and newly provided S. mekongi and S. malayensis sequences, hybridization probe-based real-time PCRs targeting SjR2 and SjCHGCS19 of the S. japonicum complex were designed both as consensus primer assays as well as multi-primer assays for the coverage of multiple variants of the target sequences. The assays were established using plasmids and S. mekongi DNA. While the consensus primer assays failed to detect S. mekongi DNA in human serum samples, the multi-primer assays showed positive or borderline positive results but only in 9.8% (6/61) of serum samples from patients with confirmed S. mekongi infections. Some cross-reactions with samples positive for S. mansoni or S. haematobium were observed but with the SjCHGCS19-PCR only. In spite of the low sensitivity, the presented experience may guide future evaluations of S. japonicum-complex-specific PCRs from human serum.

Very low prevalence of Mansonella perstans-specific cell-free DNA in serum samples of Ghanaian HIV patients

“…As known from other blood-borne helminths like Schistosoma spp. [ 28 , 29 ], multi-copy PCR-targets with ultra-high copy numbers provide best sensitivity for screenings targeting cell-free helminth DNA in serum. However, multi-copy targets with only moderate copy numbers like the internal transcribed spacer element, which was also used in the here-presented assessment, showed only a minor shift in cycle threshold values in a recent schistosomiasis study compared to Sm1-7 , which is a genomic element with ultra-high copy numbers in the genome of Schistosoma mansoni complex [ 30 ].…”

Foresight in the diagnosis of trematodiasis: innovations versus routine methods

“…Результаты проведенного анализа свидетельствуют о широкой географии проведенных исследований: большая их часть выполнена в эндемичных регионах Юго-Восточной Азии, но также изучение проводилось в странах Европы, США, Африки [12][13][14][15]. Для подтверждения диагноза большинства трематодных инвазий используется микроскопия образцов стула пациента, так как метод является простым и доступным в выполнении, однако, позволяет выявить только инвазию средней и высокой интенсивности [12,16]. Большей чувствительностью и универсальностью при низкой интенсивности инвазии обладает метод седиментации [15,17,18].…”

“…Так, при исследовании ПЦР в реальном времени на основе SjR2 и SjCHGSC19 показано, что данные маркеры можно использовать для диагностики инфекций S. mekongi в сыворотке крови человека. Но тесты обладали низкой чувствительностью, и при проведении мультипраймерной ПЦР регистрировались перекрестные реакции с образцами, положительными на S. mansoni или S. haematobium [16].…”

Oncomelania Lorelindoensis: The Intermediate Host of Sulawesi's Schistosoma Japonicum

“…[11][12][13] Schistosoma japonicum, S. malayensis, and S. mekongi cause human schistosomiasis. 14 Schistosoma japonicum is the parasite that can infect humans in Sulawesi. 7 Adult male Sulawesi S. japonicum worms are approximately ve to 12 millimeters long, and the females are approximately 10 to 14 millimeters long.…”