| Title: |
Plasmodium vivax Malaria Relapse Risk Depends on Transmission Intensity: Evidence From a Longitudinal Study in Northwest Thailand |
| Authors: |
Chu, Cindy S; Lwin, Khin Maung; Burgoine, Kathy; Phyo, Aung Pyae; Turner, Claudia; San, Thida; Aung, Aye Aye; Win, Htun Htun; Htoo, Klay; Soe, Nay Lin; Christina, Naw; Than, Hla Hla; Dah, Naw; Pilaseng, Kasiha; Wiladpaingern, Jacher; Proux, Stephane; Mukaka, Mavuto; Parker, Daniel M; Carrara, Verena I; Nosten, François; White, Nicholas J |
| Contributors: |
Wellcome Trust |
| Source: |
Open Forum Infectious Diseases ; volume 13, issue 1 ; ISSN 2328-8957 |
| Publisher Information: |
Oxford University Press (OUP) |
| Publication Year: |
2025 |
| Description: |
Background In northwest Thailand, the provision of radical cure to prevent relapses of Plasmodium vivax malaria has decreased P vivax caseloads and decreased transmission. While malaria control measures were increased, we performed a prospective observational rolling cohort study to describe the changing incidence of P vivax malaria and the associated recurrence rates. Methods Healthy nonpregnant glucose-6-phosphate dehydrogenase–normal volunteers who had symptomatic P vivax infection in the previous 12–24 months, but who had not received radical cure, were recruited. Supervised primaquine was given daily for 14 days (0.5 mg base/kg/day). Participants were followed 4 and 8 weeks later, then every 2 months until they developed symptomatic or asymptomatic P vivax malaria. Consultation for febrile illnesses was encouraged between follow-up visits. Participants who developed P vivax malaria were replaced with matched volunteers to maintain a continuous cohort of 200 participants. Results From March 2010 until September 2014, 380 healthy adults and children were enrolled. Ninety-two individuals developed P vivax malaria, 25 within 4 months of enrollment. The annual incidence of P vivax malaria infection decreased from 0.19 in 2010 to 0.09 infections per person-year in 2014. The primaquine failure rate (P vivax malaria within 4 months of treatment) was 75% less than predicted based on earlier assessments that assumed a constant hypnozoite reservoir. Conclusions Declining P vivax transmission reduces the hypnozoite reservoir in the population and the hypnozoite burden in an individual. This increases the apparent efficacy of radical cure in preelimination settings. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1093/ofid/ofaf667 |
| DOI: |
10.1093/ofid/ofaf667/65040222/ofaf667.pdf |
| Availability: |
https://doi.org/10.1093/ofid/ofaf667; https://academic.oup.com/ofid/advance-article-pdf/doi/10.1093/ofid/ofaf667/65040222/ofaf667.pdf; https://academic.oup.com/ofid/article-pdf/13/1/ofaf667/65040222/ofaf667.pdf |
| Rights: |
https://creativecommons.org/licenses/by/4.0/ |
| Accession Number: |
edsbas.D070B673 |
| Database: |
BASE |