Plasmodium species occurrence, temporal distribution and interaction in a child-aged population in rural Burkina Faso

Abstract

Background: Malaria can be caused by five Plasmodium species. Due to their higher prevalence, much of the research concentrates on Plasmodium falciparum and Plasmodium vivax. In Burkina Faso, where P. falciparum co-exists with Plasmodium malariae and Plasmodium ovale, there is not much data about the prevalence of the latter two species across human population. Moreover, interactions between co-infecting Plasmodium species are not documented. The aim of the current research is to determine species-specific prevalence and temporal distribution. The potential interactions between co-infecting Plasmodium species amongst the child-aged population in Burkina Faso are also discussed.

Methods: The study took place in the Sudanese savannah zone in Burkina Faso in a rural village, Laye. Surveys were conducted during the wet season across four years, 2007 to 2010. Volunteers aged three to 15 years with parental signed consent were enrolled. Ten children per week were screened for any history of pain, fever. Parasitological data were obtained by blood slide processing.

Results: Three sympatric Plasmodium species were recorded during this study with an average prevalence of 70.7%. Species temporal distribution showed an increase of P. malariae parasite prevalence from 0.9% in 2007 to 13.2% in 2010. Within a season, P. falciparum occurred in the overall study period while P. malariae and P. ovale were highly prevalent after the rainy part of this period. Species-specific infection analysis showed that in a comparison of mono-infections, P. malariae gametocyte prevalence and median density were higher than those of P. falciparum (88.9% vs 34.5% and 124.0 vs 40.0 gametocytes/μl, respectively). Likewise, in P. falciparum co-infections with P. malariae or P. ovale, gametocyte prevalence was also higher than in P. falciparum mono-infection. However, in P. falciparum mixed infection with P. malariae, P. falciparum gametocyte prevalence and median density as well as asexual form density decreased compared to P. falciparum mono-infection while for P. malariae mono-infection, only asexual form density significantly vary.

Conclusion: These data revealed high gametocyte prevalence in other Plasmodium species than P. falciparum with a significant variation of P. malariae gametocyte carriers and gametocyte density across years. Molecular tools and entomological studies are needed to highly assess species-specific contribution to malaria transmission.

Figure 1

Plasmodium species temporal variation across the study period: parasites prevalence (A) and mean density (B). The rainfall data were obtained from the country’s meteorological data collection and reporting system. Plasmodium falciparum reached its maximum prevalence and density in August-October during the rainy season while Plasmodium malariae and Plasmodium ovale peaked nearer the end of the rainy season.