Sub-microscopic gametocyte carriage in febrile children living in different areas of Gabon

Abstract

BackgroundConsidering malaria prevalence declines in parts of sub-Saharan Africa, such as Gabon, identification of the human infectious reservoir is important for successful malaria control. Microscopic and sub-microscopic parasites contribute to malaria transmission. The aim of the present study was to evaluate the proportion of microscopic and sub-microscopic gametocyte carriers among febrile patients in two different areas of Gabon.MethodsSamples from febrile children aged less than 11 years old were collected from February 2008 to January 2009 at two health centres of Gabon. Patients were screened for the presence of asexual Plasmodium falciparum parasites. Gametocyte carriage was determined by microscopy and QT-NASBA.ResultsGametocytes were detected in 5.3% (n = 16/304) of children by microscopy compared to 45.7% (n = 139/304) by QT-Nasba. Sub-microscopic gametocyte carriage (ie microscopy negative and QT-Nasba positive) was found in 89.2% (n = 124/139) of patients. Among patients with microscopically detected trophozoites, the proportion of sub-microscopic gametocyte (SMG) carriers was 58.4% (n = 118/202) and 6% in samples from children with negative slides (p < 0.01). In Oyem, where malaria prevalence is three-fold higher than in Owendo, SMG carriage was more frequent (49.0% vs 32.6% in Owendo; p < 0.01).ConclusionSub-microscopic gametocytaemia is common among Gabonese febrile children. They might strongly contribute to maintain malaria transmission. However, further analysis of sub-microscopic parasite carriage among asymptomatic individuals will be helpful to better characterize malaria transmission.

Plasmodium falciparum infection in febrile Congolese children: prevalence of clinical malaria 10 years after introduction of artemisinin‐combination therapies

“…A study in Kenya of asymptomatic children showed the common presence of gametocytaemia in children, especially in under‐fives. Similarly in Gabon, submicroscopic gametocytaemia was common in febrile children . With the falling malaria prevalence in many malaria endemic areas in sub‐Saharan Africa , targeting gametocytes is important to maintain malaria control and elimination.…”

“…Similarly in Gabon, submicroscopic gametocytaemia was common in febrile children . With the falling malaria prevalence in many malaria endemic areas in sub‐Saharan Africa , targeting gametocytes is important to maintain malaria control and elimination. Unfortunately, we did not investigate the presence of gametocytes in isolates collected from Congolese children.…”

Submicroscopic Falciparum Malaria in Febrile Individuals in Urban and Rural Areas of Gabon

“…In 2008, 49% of children from rural areas and 32.6% of those from urban areas carried submicroscopic gametocytemia. 11 In 2011, in a study performed in Libreville, submicroscopic gametocytes were found in 34.6% of pregnant women. 15 A similar proportion (32%) was found in this study.…”

“…Nucleic acids were extracted with a semiautomated Mini-Mag analyzer (Biomérieux sa, Lyon, France), as previously described. 11 In brief, the blood spots on the filter paper were cut in four and each piece was placed in a sterile 1.5-mL tube at room temperature. Nuclisens lysis buffer (Biomérieux sa, Lyon, France) was heated in a water bath at 37°C for 30 minutes and then added to the sample-containing tubes.…”

“…Quantitative nucleic acid sequence-based amplification (QT-NASBA) with 18S rRNA and Pfs25 mRNA was used for parasite and gametocyte detection. 11,12 All samples, including positive and negative controls (filter paper free of DNA/RNA), *Address correspondence to Denise P. Mawili-Mboumba, Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon. E-mail: dpmawili@ gmail.com were analyzed in duplicate.…”