Interaction of helminth parasites with the haemostatic system of their vertebrate hosts: a scoping review

Helminth parasitoses are among the most prevalent health issues worldwide. Their control depends largely on unravelling host–parasite interactions, including parasitic exploitation of the host haemostatic system. The present study undertakes a scoping review of the research carried out in this field with the aim of unifying and updating concepts. Multiple keywords combined with Boolean operators were employed to design the literature search strategy. Two online databases were used to identify original peer-reviewed articles written in English and published before 1st January 2020 describing molecular interactions between helminth parasites and the host haemostatic system. Relevant data from the selected sources of evidence were extracted and analysed. Ninety-six publications reporting 259 interactions were selected. Fifty-three proteins belonging to 32 species of helminth parasites were involved in interactions with components of the host haemostatic system. Many of these proteins from both parasite and host were conserved among the different interactions identified. Most of these interactions were related to the inhibition of the coagulation system and the activation of fibrinolysis. This was associated mainly with a potential of parasites to reduce the formation of blood clots in the host and attributed to biological processes, such as parasite nutrition, survival, invasion, evasion and migration or the appearance of pathological mechanisms in the host. A wide range of helminth parasites have developed similar strategies to exploit the haemostatic system of their hosts, which could be regarded as an evolutionary conserved mechanism that could confer benefits to parasites in terms of survival and establishment in their vertebrate hosts.

Description of the parasitic material used to study the interaction described. It will be defined as the name of the native protein, protein extract, protein fraction, recombinant protein or whole parasite indicated in the article

Protein compartment
Protein compartment in which the interaction is described. It will be defined as EXCRETORY/SECRETORY, SOMATIC, SURFACE or WHOLE PARASITE. If experiments described in the article reveal the location of the molecule responsible for the interaction in additional protein compartment(s) (after "/") to those in which the interaction is found (before "/"), both data will be separated by "/"

Type of interaction
Effect of the parasitic material employed to study the interaction on the component of the host haemostatic system analysed. It will be defined as it is described in the article

Interacting component of the host haemostatic system
Molecule or step of the host haemostatic system to which the parasitic material interacts. It will be defined as it is described in the article

Interaction study technique
Technique(s) employed to demonstrate the interaction between the parasitic material and the component of the host haemostatic system. It will be defined as it is described in the article

Interacting parasite molecule identified
In case of protein extracts, protein fractions and whole parasites, parasite molecule(s) identified in these parasitic materials as responsible for the interaction with the host haemostatic system. It will be defined as it is described in the article

Identification technique
In case of protein extracts, protein fractions and whole parasites, technique(s) employed to identify the molecule(s) responsible for the interaction with the host haemostatic system in these parasitic materials. It will be defined as it is described in the article Interacting pathway of the host haemostatic system Pathway of the host haemostatic system to which the parasitic material interacts. It will be defined as COAGULATION or FIBRINOLYSIS Effect on blood clot formation/dissolution in the host Potential effect attributed by the authors of the publication to the interaction in relation to the formation/dissolution of blood clots in the host. It will be defined as ANTICOAGULANT, PRO-COAGULANT, ANTI-FIBRINOLYTIC or PRO-FIBRINOLYTIC Biological process attributed to the Biological process(es) in which the interaction could participate according to the authors of the publication. It will be defined as interaction COUNTERBALANCE, ESTABLISHMENT, EVASION, INVASION, MIGRATION, MODULATION, NUTRITION, PATHOGENESIS or SURVIVAL. The concrete process(es) described in the article will be indicated in parenthesis Validation of the attributed process When the participation of the interaction in the biological process(es) attributed by the authors of the publication is experimentally validated. It will be defined as YES or NO. The concrete function(s) demonstrated will be indicated in parenthesis All the Excel cells that appear empty in Supplementary Data correspond to data that could not be extracted from the analysed publications. The symbol "-" was used to reflect this lack of information in those cases in which other data had to be inserted in the same cell (when the symbol "/" was used) or when data to be entered did not correspond to the cell in question.