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Defining the optimal diagnostic tools for evaluating onchocerciasis elimination efforts in areas co-endemic for other filarial nematodes is imperative. This study compared three published polymerase chain reaction (PCR) methods: the Onchocerca volvulus–specific qPCR-O150, the pan-filarial qPCR melt curve analysis (MCA), and the O150-PCR enzyme-linked immunosorbent assay (ELISA) currently used for vector surveillance in skin snip biopsies (skin snips) collected from the Democratic Republic of the Congo. The pan-filarial qPCR-MCA was compared with species-specific qPCRs for Loa loa and Mansonella perstans. Among the 471 skin snips, 47.5%, 43.5%, and 27.0% were O. volvulus positive by qPCR-O150, qPCR-MCA, and O150-PCR ELISA, respectively. Using qPCR-O150 as the comparator, the sensitivity and specificity of qPCR-MCA were 89.3% and 98.0%, respectively, whereas for O150-PCR ELISA, they were 56.7% and 100%, respectively. Although qPCR-MCA identified the presence of L. loa and Mansonella spp. in skin snips, species-specific qPCRs had greater sensitivity and were needed to identify M. perstans. Most of the qPCR-MCA misclassifications occurred in mixed infections. The reduced sensitivity of O150-PCR ELISA was associated with lower microfilaria burden and with lower amounts of O. volvulus DNA. Although qPCR-MCA identified most of the O. volvulus–positive skin snips, it is not sufficiently robust to be used for stop-mass drug administration (MDA) evaluations in areas co-endemic for other filariae. Because O150-PCR ELISA missed 43.3% of qPCR-O150–positive skin snips, the qPCR-O150 assay is more appropriate for evaluating skin snips of OV-16 + children in stop-MDA assessments. Although improving the sensitivity of the O150-PCR ELISA as an alternative to qPCR might be possible, qPCR-O150 offers distinct advantages aside from increased sensitivity.
Financial support: This work was supported in part by a grant from the Bill & Melinda Gates Foundation. Jessica Prince-Guerra was funded through a competitive award from the ASM/CDC Program in Infectious Disease and Public Health Microbiology Postdoctoral Research Fellowship.
Authors’ addresses: Jessica Prince-Guerra, Hubert Department of Global Health, Emory University, Atlanta, GA, E-mail: email@example.com. Vitaliano Cama, Nana Wilson, Guilherme Ogawa, and Paul T. Cantey, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, E-mails: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, and email@example.com. Elizabeth A. Thiele, Biology Department, Vassar College, Poughkeepsie, NY, E-mail: firstname.lastname@example.org. Josias Likwela and Naomi A. Pitchouna, Programme National de la Lute Contre les Maladies Tropicales Negligees, Kinshasa, Democratic Republic of the Congo, E-mails: email@example.com and firstname.lastname@example.org. Nestor Ndakala, Jacques Muzinga wa Muzinga, and Yassa D. Ndjakani, Field Epidemiology Training Program, Centers for Disease Control and Prevention, Kinshasa, Democratic Republic of the Congo, E-mails: email@example.com, firstname.lastname@example.org, and email@example.com. Nicholas Ayebazibwe, African Field Epidemiology Network, Kampala, Uganda, E-mail: firstname.lastname@example.org. Dieudonne Mumba, Institut National de Recherche Biomedicale, Kinshasa, Democratic Republic of the Congo, E-mail: email@example.com. Antoinette K. Tshefu, Kinshasa School of Public Health, Kinshasa, Democratic Republic of the Congo, E-mail: firstname.lastname@example.org.