Homozygosity for the CD1E★02 allele is associated with a resistance to Plasmodium falciparum malaria infection in Gabonese school children

Objective:To explore the possible association between polymorphisms in CD1 genes and both asymptomatic and mild Plasmodium falciparum infection.Methods:Two clusters of 85 school children,from the village of Dienga(Gabon) were investigated.The first group was analysed for the prevalence and the multiplicity of asymptomatic Plasmodium falciparum infection,whereas the second group was screened for the frequency of malarial attacks.Results:Our findings showed that homozygosity for the CD1E★02 allele was associated with a low frequency of malarial attacks.Furthermore,a strong association between CD1E★02 homozygotes and the resistance to multiple malarial attacks was identified.The CD1A★01 allele showed a weak association with a small number of malarial attacks.Conclusion:Our results suggest a possible role of CD1E polymorphisms in malaria protection among school children and that CD1e molecules are involved in anti-malarial immunity.

Submicroscopic Plasmodial Infection May Lead to Severe Malaria in Children

Malaria is one of the leading causes of consultation in African pediatric hospitals. In Gabon, malaria transmission is perennial. Plasmodium falciparum, responsible for the most severe form of the disease, represents more than 95% of all species. In P. falciparum infection, the hyperparasitemia accounts among the main criteria of disease severity. However, in many endemic countries, a significant decrease of malaria burden accompanying with the diminution of parasite load in infected individuals has been demonstrated. The objective of the study was to analyze the occurrence of febrile syndrome in childhood and investigate whether the acute febrile illness could be associated with P. falciparum submicroscopic infection. A cross-sectional study was carried out during January to March 2013 in Franceville. A total of 203 acute febrile children were enrolled. A clinical examination and biomedical analysis including parasitological diagnosis by microscope were carried out in all the patients and PCR on microscope negative ones. Of 203 children recruited for febrile syndrome, 111 have been diagnosed positive for P. falciparum infection, 73 （35.9%） by microscope （ME） and 38 （18.71%） by PCR （submicroscopic infection = SM1） with an overall prevalence of 54.68%. Of the 11 1 P. falciparum infected individuals and according to the WHO criteria, 35 （31.53%） children showed a clinical picture of severe malaria against 76 （68.47%） others classified as uncomplicated malaria. The overall prevalence rates were therefore estimated as 17.24 （35/203） for severe cases and 37.43% （76/203） for uncomplicated ones. Clinically, these severe malaria cases （27 ME＋ and 8 PCR＋） were mainly composed of 85.71% of anaemic patients （30/35）, 71.14% of prostrated individuals （25/35） and 57.14% of children with clinical icterus （20/35）. However, only two cases of severe anaemia were observed, the remaining others cases were moderate （10） and mild anaemia （18）. More interestingly, eight submicroscopic infected patients （22.85%） were found with neurological manifestations （prostration） and all were experiencing thrombocytopenia. Lastly, 1 hyperparasitemia, 6 hypoglycemia and 2 respiratory distresses were also observed among these severe malaria cases. P. falciparum submicroscopic infection may lead to severe malaria in perennial transmission area.