Simple jQuery Dropdowns
Please use this identifier to cite or link to this item: http://repository.li.mahidol.ac.th/dspace/handle/123456789/46728
Title: The persistence and oscillations of submicroscopic Plasmodium falciparum and Plasmodium vivax infections over time in Vietnam: an open cohort study
Authors: Thuy Nhien Nguyen
Lorenz von Seidlein
Tuong Vy Nguyen
Phuc Nhi Truong
Son Do Hung
Huong Thu Pham
Tam Uyen Nguyen
Thanh Dong Le
Van Hue Dao
Mavuto Mukaka
Nicholas PJ Day
Nicholas J. White
Arjen M. Dondorp
Guy E. Thwaites
Tran Tinh Hien
Churchill Hospital
Mahidol University
Center for Malariology, Parasitology and Entomology Control
Institute of Malariology-Parasitology and Entomology (IMPE)
Oxford University Clinical Research Unit
Keywords: Medicine
Issue Date: 1-May-2018
Citation: The Lancet Infectious Diseases. Vol.18, No.5 (2018), 565-572
Abstract: © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Background: A substantial proportion of Plasmodium species infections are asymptomatic with densities too low to be detectable with standard diagnostic techniques. The importance of such asymptomatic plasmodium infections in malaria transmission is probably related to their duration and density. To explore the duration of asymptomatic plasmodium infections and changes in parasite densities over time, a cohort of participants who were infected with Plasmodium parasites was observed over a 2-year follow-up period. Methods: In this open cohort study, inhabitants of four villages in Vietnam were invited to participate in baseline and subsequent 3-monthly surveys up to 24 months, which included the collection of venous blood samples. Samples were batch-screened using ultra-sensitive (u)PCR (lower limit of detection of 22 parasites per mL). Participants found to be infected by uPCR during any of these surveys were invited to join a prospective cohort and provide monthly blood samples. We estimated the persistence of Plasmodium falciparum and Plasmodium vivax infections and changes in parasite densities over a study period of 24 months. Findings: Between Dec 1, 2013, and Jan 8, 2016, 356 villagers participated in between one and 22 surveys. These study participants underwent 4248 uPCR evaluations (11·9 tests per participant). 1874 (32%) of 4248 uPCR tests indicated a plasmodium infection; 679 (36%) of 1874 tests were P falciparum monoinfections, 507 (27%) were P vivax monoinfections, 463 (25%) were co-infections with P falciparum and P vivax, and 225 (12%) were indeterminate species of Plasmodium. The median duration of P falciparum infection was 2 months (IQR 1–3); after accounting for censoring, participants had a 20% chance of having parasitaemia for 4 months or longer. The median duration of P vivax infection was 6 months (3–9), and participants had a 59% chance of having parasitaemia for 4 months or longer. The parasite densities of persistent infections oscillated; following ultralow-density infections, high-density infections developed frequently. Interpretation: Persistent largely asymptomatic P vivax and P falciparum infections are common in this area of low seasonal malaria transmission. Infections with low-density parasitaemias can develop into much higher density infections at a later time, which are likely to sustain malaria endemicity. Funding: The Wellcome Trust, Bill & Melinda Gates Foundation.
URI: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85041565009&origin=inward
http://repository.li.mahidol.ac.th/dspace/handle/123456789/46728
ISSN: 14744457
14733099
Appears in Collections:Scopus 2018

Files in This Item:
There are no files associated with this item.


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.