A wide range of biomolecules, including proteins, are excreted and secreted from helminths and contribute to the parasite9s successful establishment, survival, and reproduction in an adverse habitat. Excretory and secretory proteins (ESP) are active at the interface between parasite and host and comprise potential targets for intervention. The intestinal nematode Strongyloides spp. exhibits an exceptional developmental plasticity in its life cycle characterized by parasitic and free-living generations. We investigated ESP from infective larvae, parasitic females, and free-living stages of the rat parasite Strongyloides ratti, which is genetically very similar to the human pathogen, Strongyloides stercoralis. Proteomic analysis of ESP revealed 586 proteins, with the largest number of stage-specific ESP found in infective larvae (196), followed by parasitic females (79) and free-living stages (35). One hundred and forty proteins were identified in all studied stages, including anti-oxidative enzymes, heat shock proteins, and carbohydrate-binding proteins. The stage-selective ESP of (1) infective larvae included an astacin metalloproteinase, the L3 Nie antigen, and a fatty acid retinoid-binding protein; (2) parasitic females included a prolyl oligopeptidase (prolyl serine carboxypeptidase), small heat shock proteins, and a secreted acidic protein; (3) free-living stages included a lysozyme family member, a carbohydrate-hydrolyzing enzyme, and saponin-like protein. We verified the differential expression of selected genes encoding ESP by qRT-PCR. ELISA analysis revealed the recognition of ESP by antibodies of S. ratti-infected rats. A prolyl oligopeptidase was identified as abundant parasitic female-specific ESP, and the effect of pyrrolidine-based prolyl oligopeptidase inhibitors showed concentration- and time-dependent inhibitory effects on female motility. The characterization of stage-related ESP from Strongyloides will help to further understand the interaction of this unique intestinal nematode with its host.

About 90% of all malaria deaths in sub-Saharan Africa occur in children under five years. Fast and reliable diagnosis of malaria requires confirmation of the presence of malaria parasites in the blood of patients with fever or history suggestive of malaria; hence a prompt and accurate diagnosis of malaria is the key to effective disease management. Confirmation of malaria infection requires the availability of a rapid, sensitive, and specific testing at an affordable cost. We compared two recent methods (the novel Partec Rapid Malaria Test® (PT) and the Binax Now® Malaria Rapid Diagnostic Test (BN RDT) with the conventional Giemsa stain microscopy (GM) for the diagnosis of malaria among children in a clinical laboratory of a hospital in a rural endemic area of Ghana.

Background: Volume substitution remains subject of controversy in the light of effusions and oedema potentially complicating this highly febrile disease. Understanding the role of myocardial and circulatory function appears to be essential for clinical management. In the present study, cardiac function and cardiac proteins have been assessed and correlated with parasitological and immunologic parameters in patients with imported Plasmodium falciparum malaria. Methods: In a prospective case-control study, 28 patients with uncomplicated and complicated P. falciparum malaria were included and findings were compared with 26 healthy controls. Cardiac function parameters were assessed by an innovative non-invasive method based on the re-breathing technique. In addition, cardiac enzymes and pro- and anti-inflammatory cytokines were measured and assessed with respect to clinical symptoms and conditions of malaria. Results: Cardiac index (CI) as a measurement of cardiac output (CO) was 21% lower in malaria patients than in healthy controls (2.7 l/min/m² versus 3.4 l/min/m²; P < 0.001). In contrast, systemic vascular resistance index (SVRI) was increased by 29% (32.6 mmHg⋅m²/(l/min) versus 23.2 mmHg⋅m²/(l/min); P < 0.001). This correlated with increased cardiac proteins in patients versus controls: pro-BNP 139.3 pg/ml versus 60.4 pg/ml (P = 0.03), myoglobin 43.6 μg/l versus 27.8 μg/l (P = < 0.001). All measured cytokines were significantly increased in patients with malaria. CI, SVRI as well as cytokine levels did not correlate with blood parasite density. Conclusions: The results support previous reports suggesting impaired cardiac function contributing to clinical manifestations in P. falciparum malaria. Findings may be relevant for fluid management and should be further explored in endemic regions.

In a search for molecules involved in the interaction between intestinal nematodes and mammalian mucosal host cells, we performed MS to identify excretory–secretory proteins from Strongyloides ratti. In the excretory–secretory proteins of the parasitic female stage, we detected, in addition to other peptides, peptides homologous with the Caenorhabditis elegans heat shock protein (HSP)‐17, named Sra‐HSP‐17.1 (∼ 19 kDa) and Sra‐HSP‐17.2 (∼ 18 kDa), with 49% amino acid identity. The full‐length cDNAs (483 bp and 474 bp, respectively) were identified, and the genomic organization was analyzed. To allow further characterization, the proteins were recombinantly expressed and purified. Profiling of transcription by quantitative real‐time‐PCR and of protein by ELISA in various developmental stages revealed parasitic female‐specific expression. Sequence analyses of both the DNA and amino acid sequences showed that the two proteins share a conserved α‐crystallin domain and variable N‐terminals. The Sra‐HSP‐17s showed the highest homology with the deduced small HSP sequence of the human pathogen Strongyloides stercoralis. We observed strong immunogenicity of both proteins, leading to strong IgG responses following infection of rats. Flow cytometric analysis indicated the binding of Sra‐HSP‐17s to the monocyte–macrophage lineage but not to peripheral lymphocytes or neutrophils. A rat intestinal epithelial cell line showed dose‐dependent binding to Sra‐HSP‐17.1, but not to Sra‐HSP‐17.2. Exposed monocytes released interleukin‐10 but not tumor necrosis factor‐α in response to Sra‐HSP‐17s, suggesting the possible involvement of secreted female proteins in host immune responses.Database Nucleotide sequences for Strongyloides ratti heat shock proteins 17.1 and 17.2 have been submitted to the GenBank database under the accession numbers HQ848950 and HQ848951