Gruenberg, Maria and Hofmann, Natalie E. and Nate, Elma and Karl, Stephan and Robinson, Leanne J. and Lanke, Kjerstin and Smith, Thomas A. and Bousema, Teun and Felger, Ingrid. (2020) qRT-PCR versus IFA-based quantification of male and female gametocytes in low-density Plasmodium falciparum infections and their relevance for transmission. Journal of infectious diseases, 221 (4). pp. 598-607.
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Abstract
Accurate quantification of female and male gametocytes and sex ratios in asymptomatic low-density malaria infections are important for assessing their transmission potential. Gametocytes often escape detection even by molecular methods, therefore ultralow gametocyte densities were quantified in large blood volumes.; Female and male gametocytes were quantified in 161 PCR-positive Plasmodium falciparum infections from a cross-sectional survey in Papua New Guinea. Ten-fold concentrated RNA from 800 µL blood was analyzed using female-specific pfs25 and male-specific pfmget or mssp qRT-PCR. Gametocyte sex ratios from qRT-PCR were compared with those from immunofluorescence assays (IFA).; Gametocytes were identified in 58% (93/161) P. falciparum-positive individuals. Mean gametocyte densities were frequently below 1 female and 1 male gametocyte/µL by qRT-PCR. The mean proportion of males was 0.39 (95% confidence interval, 0.33-0.44) by pfs25/pfmget qRT-PCR; this correlated well with IFA results (Pearsons r2 = 0.91; P < .001). A Poisson model fitted to our data predicted 16% P. falciparum-positive individuals that are likely to transmit, assuming at least 1 female and 1 male gametocyte per 2.5 µL mosquito bloodmeal.; Based on model estimates of female and male gametocytes per 2.5 µL blood, P. falciparum-positive individuals detected exclusively by ultrasensitive diagnostics are negligible for human-to-mosquito transmission.Estimating the transmission potential of ultralow-density malaria infections informs interventions. Almost all infections with ≥1 female and male gametocyte per 2.5 µL mosquito bloodmeal, and thus with highest likelihood of contributing to human-to-mosquito transmission, were detectable by standard molecular diagnostics.
Faculties and Departments: | 09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) 09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Former Units within Swiss TPH > Infectious Disease Modelling > Epidemiology and Transmission Dynamics (Smith) 09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Former Units within Swiss TPH > Molecular Diagnostics (Felger) |
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UniBasel Contributors: | Grünberg, Maria and Hofmann, Natalie and Smith, Thomas A. and Felger, Ingrid |
Item Type: | Article, refereed |
Article Subtype: | Research Article |
Publisher: | Oxford University Press |
ISSN: | 0022-1899 |
Note: | Publication type according to Uni Basel Research Database: Journal article |
Language: | English |
Identification Number: |
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edoc DOI: | |
Last Modified: | 05 Mar 2020 11:56 |
Deposited On: | 05 Mar 2020 11:56 |
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