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Table 1 Current parasitological techniques, related challenges and research needs for a potential application of MALDI-TOF MS as diagnostic tool for major helminths of human and veterinary importance

From: MALDI-TOF mass spectrometry as a diagnostic tool in human and veterinary helminthology: a systematic review

Characteristics Nematodes Cestodes Trematodes
Helminth species Soil-transmitted helminths: Ascaris lumbricoides; hookworm; Strongyloides stercoralis; Trichuris trichiura Tissue nematodes: Dirofilaria spp.; Trichinella spp.; Toxocara spp.; Wuchereria bancrofti and other agents causing lymphatic filariasis, Onchocerca volvulus, Loa loa; animal hookworms causing cutaneous larva migrans Taenia spp.; Diphyllobothrium latum Echinococcus spp. Schistosoma spp.; Fasciola hepatica; small liver flukes
Type of diagnostic sample (i) Stool;
(ii) Excreted worms
(i) Tissue samples;
(ii) Serum;
(iii) Extracted worms (e.g. Loa loa)
(i) Stool;
(ii) Serum (for T. solium);
(iii) Tissue samples in cysticercosis;
(iv) Excreted proglottids
(i) Stool (in animals);
(ii) Tissue biopsies, surgical samples;
(iii) Serology
(i) Stool;
(ii) Urine;
(iii) Serum;
(iv) Tissue biopsies
Parasitological standard diagnostic techniques (i) Stool microscopy (e.g. Kato-Katz technique);
(ii) PCR in reference laboratories
(i) Direct identification on biopsy samples;
(ii) Serology;
(iii) PCR in reference laboratories;
(iv) Detection of microfilariae in blood;
(v) Detection of antigen in blood (Wuchereria)
(i) Direct identification of faecally excreted proglottids;
(ii) Stool microscopy;
(iii) Serology
(i) Microscopy;
(ii) PCR of cysts and tissue samples;
(iii) Serology
(i) Stool/urine microscopy (dependent on infecting species);
(ii) Rapid diagnostic test for circulating cathodic antigen (CCA) in urine;
(iii) PCR on serum, stool or urine;
(iv) Serology
Difficulties related to currently employed diagnostics (i) Low sensitivity in light infection intensities;
(ii) Specific concentration techniques needed for S. stercoralis;
(iii) Misidentification of hookworm and S. stercoralis larvae possible;
(iv) No species differentiation between different hookworm species possible upon microscopy
(i) Serology frequently false-negative;
(ii) False-negative PCR results in case of ‘new’ species;
(iii) Lack of expertise outside specialized laboratories
(i) Eggs of related Taenia spp. are indistinguishable by microscopy;
(ii) Lack of expertise in proglottid differentiation in many laboratories
(i) Serology frequently false-negative in intact cysts;
(ii) Microscopy (similar morphology) and serology (cross-reactivity) cannot reliably distinguish between Echinococcus spp. (therapeutic implications)
(i) Low sensitivity in light infection intensities;
(ii) Microscopy and PCR fail to detect hybrid species
Research needs for MALDI-TOF application (i) Establishment of a database for identification of eggs/larvae and adult worms;
(ii) Differentiation of microscopically indistinguishable hookworm species;
(iii) Protocol development for application on stool samples and bronchial specimens
(i) Establishment of a database for identification of tissue-invasive helminths;
(ii) Species differentiation within one genus (e.g. Dirofilaria);
(iii) Application on biopsy specimens;
(iv) Detection of microfilariae in blood;
(v) Detection of antigen in blood (e.g. Wuchereria spp.)
(i) Establishment of a database for identification of Taenia proglottids and eggs;
(ii) Differentiation between T. solium eggs/proglottids and other Taenia spp.;
(iii) Protocol development for application on stool specimens
(i) Establishment of a database for species-specific identification of eggs and tissue cysts;
(ii) Protocol for application on different sample types
(i) Establishment of a database for species-specific identification;
(ii) Protocol for application on different sample types;
(iii) Detection of Schistosoma antigen(s) in serum;
(iv) Detection of products derived from helminth-specific metabolism in serum samples