Host age and Plasmodium falciparum multiclonality are associated with gametocyte prevalence: a 1-year prospective cohort study

• Published in: Malaria Journal
• Main Authors: Yaw Adomako-Ankomah, Matthew S. Chenoweth, Aaron M. Tocker, Saibou Doumbia, Drissa Konate, Mory Doumbouya, Abdoul S. Keita, Jennifer M. Anderson, Rick M. Fairhurst, Mahamadou Diakite, Kazutoyo Miura, Carole A. Long
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2017
• Subjects: Plasmodium falciparum; Malaria; Gametocytes; Longitudinal; Multiclonality; Mali; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-017-2123-2; https://doaj.org/article/6aec421afe9a4853a7276130049e6de1

Abstract Background Since Plasmodium falciparum transmission relies exclusively on sexual-stage parasites, several malaria control strategies aim to disrupt this step of the life cycle. Thus, a better understanding of which individuals constitute the primary gametocyte reservoir within an endemic population, and the temporal dynamics of gametocyte carriage, especially in seasonal transmission settings, will not only support the effective implementation of current transmission control programmes, but also inform the design of more targeted strategies. Methods A 1-year prospective cohort study was initiated in June 2013 with the goal of assessing the longitudinal dynamics of P. falciparum gametocyte carriage in a village in Mali with intense seasonal malaria transmission. A cohort of 500 individuals aged 1–65 years was recruited for this study. Gametocyte prevalence was measured monthly using Pfs25-specific RT-PCR, and analysed for the effects of host age and gender, seasonality, and multiclonality of P. falciparum infection over 1 year. Results Most P. falciparum infections (51–89%) in this population were accompanied by gametocytaemia throughout the 1-year period. Gametocyte prevalence among P. falciparum-positive individuals (proportion of gametocyte positive infections) was associated with age (p = 0.003) but not with seasonality (wet vs. dry) or gender. The proportion of gametocyte positive infections were similarly high in children aged 1–17 years (74–82% on median among 5 age groups), while older individuals had relatively lower proportion, and those aged > 35 years (median of 43%) had significantly lower than those aged 1–17 years (p < 0.05). Plasmodium falciparum-positive individuals with gametocytaemia were found to have significantly higher P. falciparum multiclonality than those without gametocytaemia (p < 0.033 in two different analyses). Conclusions Taken together, these results suggest that a substantial proportion of Pf-positive individuals carries gametocytes throughout the year, and that ...