{"doi":"10.1186/s12936-020-03374-7","title":"Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities","abstract":"BACKGROUND: The use of molecular diagnostics has revealed an unexpectedly large number of asymptomatic low-density malaria infections in many malaria endemic areas. This study compared the gains in parasite prevalence obtained by the use of ultra-sensitive (us)-qPCR as compared to standard qPCR in cross-sectional surveys conducted in Thailand, Brazil and Papua New Guinea (PNG). The compared assays differed in the copy number of qPCR targets in the parasite genome. METHODS: Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) parasites were quantified by qPCR amplifying the low-copy Pf_ and Pv_18S rRNA genes or the multi-copy targets Pf_varATS and Pv_mtCOX1. Cross-sectional surveys at the three study sites included 2252 participants of all ages and represented different transmission intensities. RESULTS: In the two low-transmission areas, P. falciparum positivity was 1.3% (10/773) (Thailand) and 0.8% (5/651) (Brazil) using standard Pf_18S rRNA qPCR. In these two countries, P. falciparum positivity by Pf_varATS us-qPCR increased to 1.9% (15/773) and 1.7% (11/651). In PNG, an area with moderate transmission intensity, P. falciparum positivity significantly increased from 8.6% (71/828) by standard qPCR to 12.2% (101/828) by us-qPCR. The proportions of P. falciparum infections not detected by standard qPCR were 33%, 55% and 30% in Thailand, Brazil and PNG. Plasmodium vivax was the predominating species in Thailand and Brazil, with 3.9% (30/773) and 4.9% (32/651) positivity by Pv_18S rRNA qPCR. In PNG, P. vivax positivity was similar to P. falciparum, at 8.0% (66/828). Use of Pv_mtCOX1 us-qPCR led to a significant increase in positivity to 5.1% (39/773), 6.4% (42/651) and 11.5% (95/828) in Thailand, Brazil, and PNG. The proportions of P. vivax infections missed by standard qPCR were similar at all three sites, with 23%, 24% and 31% in Thailand, Brazil and PNG. CONCLUSION: The proportional gains in the detection of P. falciparum and P. vivax infections by ultra-sensitive diagnostic assays were substantial at all three study sites. Thus, us-qPCR yields more precise prevalence estimates for both P. falciparum and P. vivax at all studied levels of endemicity and represents a significant diagnostic improvement. Improving sensitivity in P. vivax surveillance by us-qPCR is of particular benefit, because the additionally detected P. vivax infections signal the potential presence of hypnozoites and subsequent risk of relapse and further transmission.","journal":"Malaria Journal","year":2020,"id":78172,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":18,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9633,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":408084,"name":"Clara Antunes Moniz","orcid":null,"position":1,"is_corresponding":false},{"id":329221,"name":"Natalie Hofmann","orcid":"0000-0001-6282-5364","position":2,"is_corresponding":false},{"id":341335,"name":"Cristian Koepfli","orcid":"0000-0002-9354-0414","position":3,"is_corresponding":false},{"id":283139,"name":"Leanne J. Robinson","orcid":"0000-0001-9903-1023","position":4,"is_corresponding":false},{"id":408085,"name":"Elma Nate","orcid":null,"position":5,"is_corresponding":false},{"id":3928,"name":"Wuelton Marcelo Monteiro","orcid":"0000-0002-0848-1940","position":6,"is_corresponding":false},{"id":3926,"name":"Gisely Cardoso de Melo","orcid":"0000-0002-8155-6005","position":7,"is_corresponding":false},{"id":408086,"name":"Andrea Kuehn","orcid":null,"position":8,"is_corresponding":false},{"id":122985,"name":"André Machado Siqueira","orcid":"0000-0003-2208-0294","position":9,"is_corresponding":false},{"id":406895,"name":"Wang Nguitragool","orcid":"0000-0002-5484-7130","position":10,"is_corresponding":false},{"id":61056,"name":"Quique Bassat","orcid":"0000-0003-0875-7596","position":11,"is_corresponding":false},{"id":3855,"name":"Marcus V. G. de Lacerda","orcid":"0000-0003-3374-9985","position":12,"is_corresponding":false},{"id":334155,"name":"Jetsumon Sattabongkot","orcid":"0000-0002-3938-4588","position":13,"is_corresponding":false},{"id":283141,"name":"Ivo Müeller","orcid":"0000-0001-6554-6889","position":14,"is_corresponding":false},{"id":329225,"name":"Ingrid Felger","orcid":"0000-0003-1255-2606","position":15,"is_corresponding":false},{"id":408083,"name":"Maria Gruenberg","orcid":null,"position":0,"is_corresponding":true}],"reference_count":26,"raw_metadata":null,"created_at":"2026-07-18T21:49:40.769098Z","pmid":"32883308","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}