Light microscope observations of granulomatous reactions against developing Porocephalus crotali (Pentastomida: Porocephalida) in XXXX and @entity35 .

@entity1712 @entity32 @entity82 @entity738 @entity19 @entity75 @entity35
The development of granulomatous reactions against moulting nymphal pentastomids (Porocephalus crotali) in the tissues of @entity35 and @entity19 intermediate hosts is described. Adipose tissue and lungs are favoured sites for encystment accounting for 70% of larvae. Six moults separate the primary larva from the final infective stage which first appears about 80 days post-infection (p.i.) and is fully infective by day 120. Larvae, and particularly their cast cuticles, are the foci of granulomatous reactions characterized by an intense @entity1712 . During ecdysis, large numbers of eosinophils permeate the entire lesion but, significantly, degranulation is limited to the underside of cast cuticles where the resultant debris is endocytosed by macrophage/epithelioid cells. A pronounced asymmetry in the @entity75 , evident even in the earliest cysts, results from the accumulation of individual epithelioid @entity738 associated with cuticle fragments close to the ventral side of the developing parasite; each is circumscribed by @entity82 . External to this region are extensive tracts of tissue composed of mature plasma cells. Particularly in @entity35 , large numbers of partially degranulated mast cells (= globule leucocytes) also surround @entity738 , and mast cell granules can accumulate within macrophages and fibroblasts. @entity32 slowly subsides once the infective stage is attained. This 1 cm-long larva resides in a thin, fibrotic, C-shaped cyst and can remain viable for years: uniquely this instar retains its last moulted cuticle as a protective sheath. Nymphal instars II-VI feed predominantly upon eosinophils but we do not yet know whether this requirement is obligate.
