Fig. 1

Recommended decision flowchart for the diagnosis of abdominal angiostrongyliasis (AA). When typical clinical manifestations of AA are first observed in patients, several laboratory tests should be performed, including measurement of inflammatory blood markers and a hemogram showing cell counts and leukocyte percentages. If no eosinophilia is found, other pathologies are suspected. However, if the patient has eosinophilia, a parasitic infection is presumed to be present. A complete coprological analysis should then be performed to discard the possibility that the infection is due to other gastrointestinal parasites. An immunoagglutination assay or enzyme-linked immunosorbent assay for Angiostrongylus costaricensis is recommended if no parasitic agent is found during coprological analysis. If the latter assays are negative, a computed tomography scan is recommended to rule out possible gut malignancies. However, if the enzyme-linked immunosorbent assay or immunoagglutination tests are positive, a biopsy of the affected gut section should be analyzed to confirm infection by A. costaricensis. Key macroscopic and microscopic alterations of the gut tissue infected with this parasite are indicated. ESS Erythrocyte sedimentation speed, RCP reactive C-protein, FDP fibrinogen-derived products. This figure was created using BioRender.com