Table 1.
Overview on the study population including baseline demographics, reported history of eyeworm and of CS, L. loa microfilarial densities, presence of typical CS, presence of other swellings not typical for CS, and appearance of nodules. Notably, two individuals (8 and 16) presented themselves as having swellings but were assessed as having only nodules by the clinician. * typical CS defined as non-pitting transient swellings on the upper extremities or near the orbit, ** other swellings defined as all not consistent with the morphology of the above-mentioned description, *** CS near the orbita. M = male, F = female, MD = missing data.
Fig 1.
“Typical” Calabar swellings seen during the study of hands (A-E) and face (F) as well as an ultrasound image (G: white arrow indicating the bone, black bracket indicating the edema) of the orbital swelling depicted in (F).
Pictures A to F were taken by LV.
Fig 2.
Findings of Patient 5: A) Typical Calabar swelling on the left hand; B) Subcutaneous nodule on the volar aspect of the left distal forearm; C) Corresponding ultrasound image revealing a subcutaneous, anechoic lesion presenting as retention, with trans-fascial gap and hyperechoic structure inside the retention.
The thread like structure is less than 0.5 mm in diameter (compare to the 2 mm scale bar, still image from S2 Videos at second 14); D) Corresponding ultrasound image with annotations. Legend: RT = retention; F = filaria; SC = subcutaneous tissue; FAP = palmar antebrachial fascia (orange); FDS = flexor digitorum superficialis muscle. Pictures A and B were taken by LV.
Fig 3.
Findings of patient 16: A) Subcutaneous nodule on the right volar forearm indicated by white arrow; B) the corresponding ultrasound image showing a transversal cut of the subcutaneous nodule presenting as an anechoic retention in the ultrasound, with trans-fascial gap and hyperechoic structure inside (still image from S3 Video at second 15) and D) showing another transversal cut of the same nodule depicting multiple trans-fascial gaps (still image from S4 Video at second 6); C and E) Corresponding ultrasound images with annotations; F) a schematic depiction of the findings on ultrasound.
Legend: RT = retention; F = filaria; SC = subcutaneous tissue; FAP = palmar antebrachial fascia (orange); FDS = flexor digitorum superficialis muscle. Picture A was taken by LV.
Fig 4.
Findings of patient 17: A + B) typical Calabar swelling on the left hand: both hands in an expanded position (A) and with fists closed (B); C + D) subcutaneous nodule on the left palmar forearm, indicated by black arrow (D); E + F) the corresponding ultrasound images showing the subcutaneous nodule presenting as a retention in the ultrasound, with trans-fascial gap and hyperechoic structure inside in longitudinal (E) and transversal scan (F) (both show still images from S5 Video at seconds 3, respectively); and G + H) Corresponding ultrasound images with annotations.
Legend: RT = retention; F = filaria; SC = subcutaneous tissue; FAP = palmar antebrachial fascia (orange); FDS = flexor digitorum superficialis muscle. Pictures A to D were taken by LV.
Fig 5.
A schematic presentation of the trans-fascial migration of an adult L. loa parasite(macrofilaria), including fascial lesions and a fluid retention.
The figure is original work created by the authors. The authors are the sole copyright holders and grant permission for publication of the figure under the Creative Commons Attribution 4.0 (CC BY 4.0) license.