Histopathological and morphological studies on natural Cysticercus fasciolaris infection in liver of Wistar rats

Abstract

Descriptive morphology of multifocal hepatic cysts found in eight of forty five (17.78 %) Wistar rats sacrificed during pharmacological studies related to herbal formulations was studied. The creamish to white cysts were of varying sizes, ranging from 3-8 mm in diameter. Morphological studies of these cysts depicted the presence of metacestodes of Taenia taeniaeformis i.e. Cysticercus fasciolaris inside them. The scolex of metacestode revealed four suckers and rostellum armed with two distinct rows of characteristic pen knife shaped hooks (characteristics of taeniid cestodes). The average size of large hooks was 392.92 ± 10.12 µ and that of small hooks was 240.64 ± 14.26 µ. The average size of suckers was 304.36 ± 12.33 µ. Histopathology of hepatic tissue surrounding the cysts revealed zones of fatty change, inflammation, granulation tissue and metaplasia. However, the histopathology of stomach and small intestines didn't show any significant lesions.

Cysticercus fasciolaris (Taenia taeniaeformis Larval Stage) in Urban Rats with Illustration of Histopathological Changes in the Liver

“…Similar studies have shown two layers of connective tissue around the larva [19]. Also, aggregation of lymphocytes, plasmocytes, and eosinophils in the outer layer of cyst shows the acute nature of infection [15]. Previously, infiltration of mononuclear cells including lymphocytes, 2017 Vol.…”

“…Moreover, the infected livers had multiple cysts, which may reflect the number of ingested eggs [18]. Other studies have shown the variation in the size of the cysts that might be due to infection at different time intervals [15]. In this study, histopathology of the liver demonstrated a two layer cyst around the C. fasciolaris larva, which might be a defense mechanism to limit the growth of the larva [19].…”

“…In gross morphological studies, the size of cysts was small to moderate among different rats, which could be attributed to recent infections. Previous studies showed that the size of cysts was related to the duration of the infection [15], and the development stage of the cyst [17]. Moreover, the infected livers had multiple cysts, which may reflect the number of ingested eggs [18].…”

“…5 No. 3-4 macrophages, and eosinophils was seen in tissue sections of the liver [15,19]. There are reports of hepatic cell necrosis due to the migration of larvae through liver [20].…”

“…The cysts wall were cut open and inspected for larvae. The recovered larvae were stained with lactophenol as described elsewhere [15], and were identified based on morphological and morphometric characters of the hooks as described by others [15]. The small and large hooks were measured, and drawings were made using a microscope equipped with a camera lucida.…”