A newly developed reagent strip assay for the diagnosis of schistosomiasis based on parasite antigen detection in urine of infected individuals was evaluated. The test uses the principle of lateral flow through a nitrocellulose strip of the sample mixed with a colloidal carbon conjugate of a monoclonal antibody specific for Schistosoma circulating cathodic antigen (CCA). The strip assay to diagnose a group of highly infected schoolchildren in Mwanza, Tanzania, demonstrated a high sensitivity and association with the intensity of infection as measured both by egg counts, and by circulating anodic antigen and CCA levels determined by enzyme-linked immunosorbent assay. A specificity of ca. 90% was shown in a group of schistosome-negative schoolchildren from Tarime, Tanzania, an area where schistosomiasis is not endemic. The test is easy to perform and requires no technical equipment or special training. The stability of the strips and the conjugate in the dry format lasts for at least 3 months at ambient temperature in sealed packages, making it suitable for transport and use in areas where schistosomiasis is endemic. This assay can easily be developed to an end-user format.Diagnosis of schistosomiasis, one of the major parasitic diseases in tropical areas, is usually performed by parasitological (microscopic detection of eggs), and/or immunological methods (antibody and antigen detection) (11). The demonstration of parasite eggs in urine or feces directly indicates the presence of the worms, but the disadvantages of this approach include a high fluctuation in egg counts, easily missed low infections, and a relatively time-consuming methodology. Immunological methods such as enzyme-linked immunosorbent assays (ELISAs) usually require more advanced laboratory settings but may yield a higher sensitivity (particularly for antibody detection). However, for antibody detection, specificity may be a problem, and the efficacy of treatment remains difficult to determine since specific antibodies continue to be present long after the worms have disappeared. In this respect, detection of parasite antigens (such as circulating anodic antigen [CAA] and circulating cathodic antigen [CCA]) by ELISA (1, 3, 11) shows many advantages, such as the demonstration of active infections or of the effect of treatment, and has a high specificity. However, ELISA procedures (total assay time of ca. 3 h) remain relatively slow, even in an optimized and standardized format, and they require skilled personnel and well-equipped laboratories. In most studies involving the CAA and/or CCA ELISA on serum and urine samples, the best diagnostic performance was achieved with the urine CCA assay, with sensitivities ranging from 80 to 100% (11). For this reason and because of the relative ease of obtaining urine samples, we have investigated ways to develop a rapid field-applicable test for the detection of CCA in the urine of schistosome-infected individuals. Here, we describe the development of a lateralflow assay with carbon-labeled anti-CCA monoclon...

Carbon nanoparticles (CNPs) labeled with reporter molecules can serve as signaling labels in rapid diagnostic assays as an alternative to gold, colored latex, silica, quantum dots, or up-converting phosphor nanoparticles. Detailed here is the preparation of biomolecule-labeled CNPs and examples of their use as a versatile label. CNPs can be loaded with a range of biomolecules, such as DNA, antibodies, and proteins (e.g., neutravidin or a fusion protein of neutravidin with an enzyme), and the resulting conjugates can be used to detect analytes of high or low molecular mass.FigureScheme of a NALFIA-, NAMIA, or NALMIA. Neutravidin adsorbed onto CNPs detects biotin-labelled amplicons; the discriminating tag is recognized by its respective antibody, which is immobilized onto nitrocellulose membranes or pads

Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh) vegetables, sprouts, and occasionally fruits made clear that these pathogens are not only transmitted to humans via the “classical” routes of meat, eggs, and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure), water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals.

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Lateral Flow Immunoassays (LFIAs) allow for rapid, low-cost, screening of many biomolecules such as food allergens. Despite being classified as rapid tests, many LFIAs take 10–20 min to complete. For a really high-speed LFIA, it is necessary to assess antibody association kinetics. By using a label-free optical technique such as Surface Plasmon Resonance (SPR), it is possible to screen crude monoclonal antibody (mAb) preparations for their association rates against a target. Herein, we describe an SPR-based method for screening and selecting crude anti-hazelnut antibodies based on their relative association rates, cross reactivity and sandwich pairing capabilities, for subsequent application in a rapid ligand binding assay. Thanks to the SPR selection process, only the fast mAb (F-50-6B12) and the slow (S-50-5H9) mAb needed purification for labelling with carbon nanoparticles to exploit high-speed LFIA prototypes. The kinetics observed in SPR were reflected in LFIA, with the test line appearing within 30 s, almost two times faster when F-50-6B12 was used, compared with S-50-5H9. Additionally, the LFIAs have demonstrated their future applicability to real life samples by detecting hazelnut in the sub-ppm range in a cookie matrix. Finally, these LFIAs not only provide a qualitative result when read visually, but also generate semi-quantitative data when exploiting freely downloadable smartphone apps.