Mobile Diagnostics Based on Motion? A Close Look at Motility Patterns in the Schistosome Life Cycle.

Imaging at high resolution and subsequent image analysis with modified mobile phones have the potential to solve problems related to microscopy-based diagnostics of parasitic infections in many endemic regions. Diagnostics using the computing power of "smartphones" is not restricted by limited expertise or limitations set by visual perception of a microscopist. Thus diagnostics currently almost exclusively dependent on recognition of morphological features of pathogenic organisms could be based on additional properties, such as motility characteristics recognizable by computer vision. Of special interest are infectious larval stages and "micro swimmers" of e.g., the schistosome life cycle, which infect the intermediate and definitive hosts, respectively. The ciliated miracidium, emerges from the excreted egg upon its contact with water. This means that for diagnostics, recognition of a swimming miracidium is equivalent to recognition of an egg. The motility pattern of miracidia could be defined by computer vision and used as a diagnostic criterion. To develop motility pattern-based diagnostics of schistosomiasis using simple imaging devices, we analyzed Paramecium as a model for the schistosome miracidium. As a model for invasive nematodes, such as strongyloids and filaria, we examined a different type of motility in the apathogenic nematode Turbatrix, the "vinegar eel." The results of motion time and frequency analysis suggest that target motility may be expressed as specific spectrograms serving as "diagnostic fingerprints."

Impaired allergy diagnostics among parasite-infected patients caused by IgE antibodies to the carbohydrate epitope galactose-α 1,3-galactose.

BACKGROUND: The carbohydrate epitope galactose-α 1,3-galactose (α-Gal) is abundantly expressed on nonprimate mammalian proteins. We have recently shown that α-Gal is responsible for the IgE binding to cat IgA, a newly identified cat allergen (Fel d 5). OBJECTIVE: We sought to investigate the diagnostic relevance of IgE antibodies to Fel d 5 and α-Gal among parasite-infected patients from central Africa without cat allergy compared with patients with cat allergy from the same region. METHODS: Sera from 47 parasite-infected patients and 31 patients with cat allergy were analyzed for total IgE and IgE antibodies against cat dander extract (CDE) by using the ImmunoCAP system. Inhibition assay was performed with α-Gal on solid phase-bound CDE. The presence of IgE specific for the major cat allergen Fel d 1, Fel d 5, and α-Gal was analyzed by means of ELISA. RESULTS: Among the 47 parasite-infected patients, 85% had IgE antibodies against α-Gal (OD; median, 0.175; range, 0.102-1.466) and 66% against Fel d 5 (OD; median, 0.13; range, 0.103-1.285). Twenty-four of the parasite-infected patients were sensitized to CDE, and 21 of them had IgE antibodies to Fel d 5 and α-Gal. There was no correlation between IgE levels to CDE and rFel d 1 among the parasite-infected patients but a strong correlation between CDE and Fel d 5 and α-Gal (P < .001). Among the group with cat allergy, only 5 patients had IgE to α-Gal, and nearly 75% (n = 23) had IgE to rFel d 1 (median, 7.07 kU(A)/L; range, 0.51-148.5 kU(A)/L). In contrast, among the patients with cat allergy, there was a correlation between IgE levels to CDE and rFel d 1 (P < .05) but no correlation between CDE and Fel d 5 and α-Gal. CONCLUSION: IgE to α-Gal causes impaired allergy diagnostics in parasite-infected patients. Screening for IgE to rFel d 1 and other allergens without carbohydrates might identify patients with true cat sensitization/allergy in parasite-infested areas.

Web-based virtual microscopy for parasitology: a novel tool for education and quality assurance.

BACKGROUND: The basis for correctly assessing the burden of parasitic infections and the effects of interventions relies on a somewhat shaky foundation as long as we do not know how reliable the reported laboratory findings are. Thus virtual microscopy, successfully introduced as a histopathology tool, has been adapted for medical parasitology. METHODOLOGY/PRINCIPAL FINDINGS: Specimens containing parasites in tissues, stools, and blood have been digitized and made accessible as a "webmicroscope for parasitology" (WMP) on the Internet (http://www.webmicroscope.net/parasitology).These digitized specimens can be viewed ("navigated" both in the x-axis and the y-axis) at the desired magnification by an unrestricted number of individuals simultaneously. For virtual microscopy of specimens containing stool parasites, it was necessary to develop the technique further in order to enable navigation in the z plane (i.e., "focusing"). Specimens were therefore scanned and photographed in two or more focal planes. The resulting digitized specimens consist of stacks of laterally "stiched" individual images covering the entire area of the sample photographed at high magnification. The digitized image information (approximately 10 GB uncompressed data per specimen) is accessible at data transfer speeds from 2 to 10 Mb/s via a network of five image servers located in different parts of Europe. Image streaming and rapid data transfer to an ordinary personal computer makes web-based virtual microscopy similar to conventional microscopy. CONCLUSION/SIGNIFICANCE: The potential of this novel technique in the field of medical parasitology to share identical parasitological specimens means that we can provide a "gold standard", which can overcome several problems encountered in quality control of diagnostic parasitology. Thus, the WMP may have an impact on the reliability of data, which constitute the basis for our understanding of the vast problem of neglected tropical diseases. The WMP can be used also in the absence of a fast Internet communication. An ordinary PC, or even a laptop, may function as a local image server, e.g., in health centers in tropical endemic areas.

Schistosomiasis in Swedish travellers to sub-Saharan Africa: Can we rely on serology?

In the absence of egg excretion, laboratory diagnosis of recently acquired schistosomiasis is dependent on serology. 42 of 83 Swedish adventure tourists to sub-Saharan Africa had serum anti-schistosome antibodies indicating recent infection. There is little doubt regarding the specificity and sensitivity of serology for the demonstration of infection, but there is a need for alternative serological methods which could be more widely used than the standard immunofluorescence assay (IFA) for antibodies against gut-derived antigens (anti-GAA). We present results suggesting that 40/42 anti-GAA positive cases also react with keyhole limpet haemocyanin (KLH), a readily available commercial antigen. High anti-GAA titres were seen for more than 2 y despite treatment with praziquantel. Thus we are faced with several questions. How likely is it that positive serology means treatment failure? What is the risk involved in chronic infection? What is the prospect for monitoring treatment outcome by serology? We conclude that there is a need for better information on the risk of becoming infected, for improved methods for testing and for monitoring the therapeutic effects in adventure tourists.

Localization and identification of Schistosoma mansoni/KLH-crossreactive components in infected mice.

KLH (Keyhole limpet hemocyanin) is highly immunogenic, and crossreactive epitopes occur widely in nature. In schistosomiasis, infected hosts generate antibodies reactive with KLH. This is of diagnostic importance but we lack detailed information on the immunogen-carrying molecules and their distribution in the worm. We used anti-KLH antibodies to localize cross-reacting epitopes in the various developmental stages of the parasite in experimental Schistosoma mansoni infection. The staining results show KLH crossreactivity in the life stages of the parasite. By immunoblotting we show that KLH-crossreactive antigenic epitopes in the parasite eggs are carbohydrates, also recognized by antibodies against soluble schistosome egg antigens. The localizations in the larval stages and in adult worms suggest that crossreacting antigenic epitopes are secretory products.