Expert consensus on case definitions in human loiasis: a Delphi study.

This study aimed to achieve consensus on the case definitions and clinical aspects of loiasis, a filarial parasite infection caused by Loa loa, in order to support the development of guidelines for diagnosis and clinical management and to provide harmonised definitions for future research and scientific communication. We applied the Delphi method. Statements on the definition of eyeworm, Calabar swelling, possible/probable/confirmed loiasis, occult loiasis, and the classification of loiasis clinical manifestations were submitted individually to a panel of 18 experts participating in the guideline development. Replies were managed anonymously. Round 1 mapped the definitions used by experts, and rounds 2-4 aimed to reach consensus, or quantify disagreement, with the proposed statements. Data were analysed using percentages, medians, and IQRs. The study was terminated based on consensus or stability-related and time-related criteria. The 18 experts participated in all rounds. Consensus on the proposed definitions was reached with 83·3-100% agreement and IQR less than or equal to 1. Notably, agreement was obtained on avoiding the term occult loiasis due to its ambiguity. Although initially intended for imported loiasis, the definitions proposed in this Delphi consensus study might also be applicable in both endemic and non-endemic areas. These consensus definitions will support the ongoing development of guidelines for the diagnosis and management of loiasis and facilitate harmonised research, as well as scientific and clinical communication.