Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Dec 9;17(1):220.
doi: 10.1186/s12916-019-1456-9.

Differential impact of malaria control interventions on P. falciparum and P. vivax infections in young Papua New Guinean children

Maria Ome-Kaius  1   2   3 , Johanna Helena Kattenberg  1   2   4 , Sophie Zaloumis  3 , Matthew Siba  1 , Benson Kiniboro  1 , Shadrach Jally  1 , Zahra Razook  2 , Daisy Mantila  1 , Desmond Sui  1 , Jason Ginny  1 , Anna Rosanas-Urgell  4 , Stephan Karl  1   2 , Thomas Obadia  5 , Alyssa Barry  2 , Stephen J Rogerson  3 , Moses Laman  1 , Daniel Tisch  6 , Ingrid Felger  7 , James W Kazura  6 , Ivo Mueller  2   3   5 , Leanne J Robinson  8   9   10   11
Affiliations

Differential impact of malaria control interventions on P. falciparum and P. vivax infections in young Papua New Guinean children

Maria Ome-Kaius et al. BMC Med. .

Abstract

Introduction: As malaria transmission declines, understanding the differential impact of intensified control on Plasmodium falciparum relative to Plasmodium vivax and identifying key drivers of ongoing transmission is essential to guide future interventions.

Methods: Three longitudinal child cohorts were conducted in Papua New Guinea before (2006/2007), during (2008) and after scale-up of control interventions (2013). In each cohort, children aged 1-5 years were actively monitored for infection and illness. Incidence of malaria episodes, molecular force of blood-stage infections (molFOB) and population-averaged prevalence of infections were compared across the cohorts to investigate the impact of intensified control in young children and the key risk factors for malaria infection and illness in 2013.

Results: Between 2006 and 2008, P. falciparum infection prevalence, molFOB, and clinical malaria episodes reduced by 47%, 59% and 69%, respectively, and a further 49%, 29% and 75% from 2008 to 2013 (prevalence 41.6% to 22.1% to 11.2%; molFOB: 3.4 to 1.4 to 1.0 clones/child/year; clinical episodes incidence rate (IR) 2.6 to 0.8 to IR 0.2 episodes/child/year). P. vivax clinical episodes declined at rates comparable to P. falciparum between 2006, 2008 and 2013 (IR 2.5 to 1.1 to 0.2), while P. vivax molFOB (2006, 9.8; 2008, 12.1) and prevalence (2006, 59.6%; 2008, 65.0%) remained high in 2008. However, in 2013, P. vivax molFOB (1.2) and prevalence (19.7%) had also substantially declined. In 2013, 89% of P. falciparum and 93% of P. vivax infections were asymptomatic, 62% and 47%, respectively, were sub-microscopic. Area of residence was the major determinant of malaria infection and illness.

Conclusion: Intensified vector control and routine case management had a differential impact on rates of P. falciparum and P. vivax infections but not clinical malaria episodes in young children. This suggests comparable reductions in new mosquito-derived infections but a delayed impact on P. vivax relapsing infections due to a previously acquired reservoir of hypnozoites. This demonstrates the need to strengthen implementation of P. vivax radical cure to maximise impact of control in co-endemic areas. The high heterogeneity of malaria in 2013 highlights the importance of surveillance and targeted interventions to accelerate towards elimination.

Keywords: Epidemiology; Incidence; Malaria control; P. falciparum; P. vivax; Papua New Guinea; Prevalence.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Study and intervention timeline. Legend: The timeline shows the time-points when the three cohorts were conducted in reference to malaria control interventions that occurred in the study area
Fig. 2
Fig. 2
Changing burden of malaria infections and illness across the different time-points of malaria control intensification in the study area. Legend: Impact of improved malaria control on prevalence of infections detectable by a polymerase chain reaction assay (PCR), b light microscopy (LM), c incidence of new blood-stage infections (molFOB) and d incidence of clinical malaria episodes. Error bars are 95% confidence intervals
See this image and copyright information in PMC

References

    1. W.H.O. World Malaria Report 2018. Geneva: World Health Organization; [https://apps.who.int/iris/bitstream/handle/10665/275867/9789241565653-en.... Accessed: 01 May 2019.
    1. Coura JR, Suarez-Mutis M, Ladeia-Andrade S. A new challenge for malaria control in Brazil: asymptomatic Plasmodium infection--a review. Mem Inst Oswaldo Cruz. 2006;101(3):229–237. doi: 10.1590/S0074-02762006000300001. - DOI - PubMed
    1. Nguitragool W, Karl S, White M, Koepfli C, Felger I, Singhasivanon P, et al. Highly heterogeneous residual malaria risk in western Thailand. Int J Parasitol. 2019;49(6):455–462. doi: 10.1016/j.ijpara.2019.01.004. - DOI - PMC - PubMed
    1. W.H.O. W.P.R.O. Meeting Report: Malaria Programme Managers Meeting to review progress on implementation of the regional action framework for malaria control and elimmination in the Western Pacific 2016–2020 [https://iris.wpro.who.int/bitstream/handle/10665.1/14326/RS-2018-GE-31-P.... Accessed: 02 May 2019.
    1. Harris I, Sharrock WW, Bain LM, Gray KA, Bobogare A, Boaz L, et al. A large proportion of asymptomatic Plasmodium infections with low and sub-microscopic parasite densities in the low transmission setting of Temotu Province, Solomon Islands: challenges for malaria diagnostics in an elimination setting. Malar J. 2010;9:254. doi: 10.1186/1475-2875-9-254. - DOI - PMC - PubMed

Publication types