Bélgica Vásquez; Claudio Rojas & Carlos Manterola

Although cystic echinococcosis (CE) is an endemic disease in several parts of the world, few morphological and quantitative studies of the fundamental structures of Echinococcus granulosus in humans, especially protoscolices. The aim of this study was to perform a morphoquantitative analysis of protoescolex and other funda- mental structures of E. granulosus from human hosts. Cross- sectional study. Eight human hepatic EQ specimens were studied, applying non-probabilistic convenience sampling. Cystic layers, fluid and hydatid grit were evaluated. The layers were fixed in 10% buffered formaldehyde and processed for embedding in paraplast. Slices of 5 μm thickness were made and stained with H-E for light microscopic analysis. The liquid and grit were centrifuged and the sediment obtained was analyzed directly to determine the morphometric measurements of the protoscolices and the large and small hooks. Descriptive statistics were used. Of the 8 cysts studied, 6 were univesicular cysts, one multivesicular and one abscessed cyst, whose lamellar and germinative layers were well defined. The proligerous vesicles had a rounded shape with protoscolices inside. The invaginated protoscolices had an average length and width of 140.8 ± 34.3 μm and 106.2 ± 29.5 μm, respectively; and the developed ones had a length of 237.2 ± 53.0 μm and width of 128.7 ± 32.0 μm. The rostellar hooks presented smooth contours distributed in two regular rows. The average total length of the large and small hooks was 20.1 ± 2.7 μm; the average total width was 7.4 ± 1.2 μm. In conclusion, the morphoquantitative characteristics of E. granulosus hooks in humans are distinct from other intermediate host species and from other Echinococcus spp. It is possible that the abandonment of the resistance state of the invaginated protoscolices until their development generates epidemiological implications of interest.

KEY WORDS: Echinococcus granulosus; Protoscolex; Echinococcosis; Hydatidosis; Hydatid Cyst.

VÁSQUEZ, B.; ROJAS, C. & MANTEROLA, C. Estudio morfocuantitativo de protoescólices y otras estructuras fundamentales de Echinococcus granulosus de hospederos humanos. Int. J. Morphol., 40(6):1630-1640, 2022.