Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections

Amal A H Gadalla, Petra Schneider, Thomas S. Churcher, Elkhansaa Nassir, Abdel Muhsin A Abdel-Muhsin, Lisa C. Ranford-Cartwright, Sarah E. Reece, Hamza A. Babiker

Research output: Contribution to journalArticle

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Abstract

Introduction In a markedly seasonal malaria setting, the transition from the transmission-free dry season to the transmission season depends on the resurgence of the mosquito population following the start of annual rains. The sudden onset of malaria outbreaks at the start of the transmission season suggests that parasites persist during the dry season and respond to either the reappearance of vectors, or correlated events, by increasing the production of transmission stages. Here, we investigate whether Plasmodium falciparum gametocyte density and the correlation between gametocyte density and parasite density show seasonal variation in chronic (largely asymptomatic) carriers in eastern Sudan. Materials and Methods We recruited and treated 123 malaria patients in the transmission season 2001. We then followed them monthly during four distinct consecutive epidemiological seasons: transmission season 1, transmission-free season, pre-clinical period, and transmission season 2. In samples collected from 25 participants who fulfilled the selection criteria of the current analysis, we used quantitative PCR (qPCR) and RT-qPCR to quantify parasite and gametocyte densities, respectively. Results and Discussion We observed a significant increase in gametocyte density and a significantly steeper positive correlation between gametocyte density and total parasite density during the pre-clinical period compared to the preceding transmission-free season. However, there was no corresponding increase in the density or prevalence of total parasites or gametocyte prevalence. The increase in gametocyte production during the pre-clinical period supports the hypothesis that P. falciparum may respond to environmental cues, such as mosquito biting, to modulate its transmission strategy. Thus, seasonal changes may be important to ignite transmission in unstable-malaria settings.

Original languageEnglish
Article numbere0166699
JournalPLoS One
Volume11
Issue number11
DOIs
Publication statusPublished - Nov 1 2016

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gametocytes
Plasmodium falciparum
Malaria
infection
malaria
parasites
Parasites
dry season
Culicidae
quantitative polymerase chain reaction
Sudan
selection criteria
Polymerase Chain Reaction
Rain
seasonal variation
Patient Selection
rain
Cues
Disease Outbreaks

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Gadalla, A. A. H., Schneider, P., Churcher, T. S., Nassir, E., Abdel-Muhsin, A. M. A., Ranford-Cartwright, L. C., ... Babiker, H. A. (2016). Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections. PLoS One, 11(11), [e0166699]. https://doi.org/10.1371/journal.pone.0166699

Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections. / Gadalla, Amal A H; Schneider, Petra; Churcher, Thomas S.; Nassir, Elkhansaa; Abdel-Muhsin, Abdel Muhsin A; Ranford-Cartwright, Lisa C.; Reece, Sarah E.; Babiker, Hamza A.

In: PLoS One, Vol. 11, No. 11, e0166699, 01.11.2016.

Research output: Contribution to journalArticle

Gadalla, AAH, Schneider, P, Churcher, TS, Nassir, E, Abdel-Muhsin, AMA, Ranford-Cartwright, LC, Reece, SE & Babiker, HA 2016, 'Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections', PLoS One, vol. 11, no. 11, e0166699. https://doi.org/10.1371/journal.pone.0166699
Gadalla AAH, Schneider P, Churcher TS, Nassir E, Abdel-Muhsin AMA, Ranford-Cartwright LC et al. Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections. PLoS One. 2016 Nov 1;11(11). e0166699. https://doi.org/10.1371/journal.pone.0166699
Gadalla, Amal A H ; Schneider, Petra ; Churcher, Thomas S. ; Nassir, Elkhansaa ; Abdel-Muhsin, Abdel Muhsin A ; Ranford-Cartwright, Lisa C. ; Reece, Sarah E. ; Babiker, Hamza A. / Associations between season and gametocyte dynamics in chronic plasmodium falciparum infections. In: PLoS One. 2016 ; Vol. 11, No. 11.
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