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Uncommon asymptomatic Plasmodium falciparum infections in Gabonese children
Michel A Missinou1, Bertrand Lell, Peter G Kremsner
1Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon.
Insights
Asymptomatic Plasmodium falciparum malaria is uncommon in young Gabonese children, with most infections presenting symptoms immediately. This suggests malaria incidence is often underestimated in endemic areas.
Area of Science:
- Tropical Medicine
- Infectious Diseases
- Pediatrics
Background:
- Malaria remains a significant global health challenge, particularly in sub-Saharan Africa.
- Understanding the dynamics of Plasmodium falciparum infections, including asymptomatic cases, is crucial for effective control strategies.
Purpose of the Study:
- To determine the prevalence of asymptomatic Plasmodium falciparum infections in young children in a hyperendemic region of Gabon.
- To identify factors associated with asymptomatic malaria infections in this population.
Main Methods:
- Longitudinal cohort study of 200 children in Gabon.
- Detailed monitoring of Plasmodium falciparum infection status and clinical presentation.
- Statistical analysis to identify associations with host factors (sickle cell trait, G6PD deficiency, TNF promoter mutation).
Main Results:
- Out of 660 Plasmodium falciparum infections, 77% were symptomatic upon detection.
- Only 7% of infections were preceded by an asymptomatic phase longer than 4 days.
- Sickle cell trait, glucose-6-phosphate dehydrogenase deficiency, and a specific tumor necrosis factor promoter mutation were significantly linked to asymptomatic infections.
Conclusions:
- True asymptomatic Plasmodium falciparum infections are infrequent in young children in this hyperendemic setting.
- Relying on single or infrequent measurements significantly underestimates malaria incidence.
- Host genetic factors play a role in the clinical manifestation of malaria.
Abstract:
To assess the frequency of asymptomatic plasmodial infections in young children living in an area of hyperendemicity, a cohort of 200 children in Gabon was investigated longitudinally. Of 660 cases of Plasmodium falciparum infection, 77% were symptomatic at the time they were identified and only 7% were preceded by an asymptomatic phase of >4 days. Sickle cell trait, glucose-6-phosphate dehydrogenase deficiency, and mutation in the promoter region of tumor necrosis factor (TNF(-376A/-238A)) were significantly associated with asymptomatic P. falciparum infection (P=.03, P=.009, and P<.001, respectively). We conclude that true asymptomatic cases of P. falciparum infection are uncommon in young children and that single measurements or measurements made at long time intervals will lead to a strong underestimation of the incidence of malaria.