Background: Malaria, filariasis, and intestinal parasitic infections (IPIs) are common and frequently overlap in developing countries. The prevalence and predictors of these infections were investigated in three different settlements (rural, semi-urban, and urban) of Gabon.

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Plasmodium falciparum infection can lead to a life threatening disease and the pathogenetic mechanisms of severe manifestations are not fully understood. Here, we investigated the capacity of P. falciparum-parasitized red blood cells (PRBC) from 45 children with clinical malaria to induce endothelial cell (EC) apoptosis. In all subjects, PRBC that cytoadhered to ECs could be found albeit to a variable degree. By contrast, PRBC that induce EC apoptosis were found only in nine (20%) subjects. Interestingly, children with neurological manifestations were significantly more likely to harbour apoptogenic strains. There was no quantitative relationship between the capacity of these isolates to cytoadhere and apoptosis induction. We hypothesize that P. falciparum-encoded molecules could be responsible for apoptosis induction and therefore suggest new insights in the pathogenesis of P. falciparum malaria. Further investigations are currently in progress to determine whether these results can be confirmed and to identify putative parasite apoptogenic factors.

This is the first attempt to identify genes involved in parasite pathogenic mechanisms against human ECs. The finding of PALPFs illuminates perspectives for novel therapeutic strategies against cerebral complications of malaria.

Abstract. The development of control strategies for loiasis is of crucial importance in endemic areas and depends heavily on the accurate identification of occult-infected individuals. A polymerase chain reaction (PCR) and nested polymerase chain reaction (nested PCR) were developed and based on sequences of the repeat 3 region (15r3) of the gene encoding a Loa loa 15-kD protein. The assays was performed on 20 blood samples from occult-infected subjects and 30 from field-collected amicrofilaremic individuals. The size of the initial PCR product was 396 basepairs (bp). When this initial amplification using primers 15r3 1 and 15r3 2 was carried out for 30 cycles, the PCR products from three of the 20 occult-infected and five of the 30 amicrofilaremic individuals were visualized after electrophoresis by staining the gel with ethidium bromide. Subsequent Southern blotting and hybridization with the specific probe revealed hybridization in 19 of 20 occult-infected and 23 of 30 amicrofilaremic samples but only after two days of exposure of the blot to the x-ray film. When the nested PCR was carried out (product size ϭ 366 bp, primers 15r3 3 and 15r3 4 ), 19 of 20 occult-infected and 23 of 30 amicrofilaremic samples that were positive by Southern hybridization of the initial PCR products were strongly positive by staining with ethidium bromide. Qualitative Southern blotting of the nested PCR products using the same probe previously described confirmed the ethidium bromide staining results after a very short exposure time of 4 hr. These results demonstrate that the nested PCR amplification product is specific and that its sensitivity in detecting occult loiasis is 95%. This approach has significant promise for the screening of large human populations for active loiasis without the requirement for blotting and hybridization of the PCR products.The filarial parasite Loa loa is transmitted by Chrysops dimidiala and C. silacea (family Tabanidae). This parasite has been estimated to cause chronic infection in as many as 13 million people in west and central Africa. The major clinical presentations are calabar angioedema and pruritus, although the majority of individuals with heavy microfilarial loads are asymptomatic. In exceptional cases, serious sequelae such as endomyocardial fibrosis, renal complications, and encephalitis have been reported. 1 In an endemic area, two-thirds of the infected subjects do not have circulating microfilariae (occult loiasis). 2 Microscopy is universally used for both epidemiologic data collection and medical diagnosis of human loiasis, but this method is unable to detect occult infections. Various antibody-based assays have been used to measure host antibodies in L. loa-exposed or -infected individuals. However, the major limitation of serologic tests for filarial infections, such as loiasis, is their low specificity due to the cross-reactivity among filarial antigens. Furthermore, these antibody-based assays cannot always distinguish between past and current infections, nor can they be used t...