An insight into the epidemiology of foodborne zoonotic fascioliasis in small ruminants in northwestern region of Bangladesh

Abstract

Fascioliasis is one of the most common foodborne zoonotic infection of ruminants in Bangladesh. To estimate the prevalence and associated risk factors of fascioliasis and extent of liver damage, 825 livers of sheep and goats were randomly inspected during onsite slaughterhouse visiting in Naogaon, Natore, Rajshahi and Joypurhat districts. The overall prevalence of fascioliasis was 25.09% and significantly (P = 0.008) higher in goats (26.11%) than sheep (24.00%). During gross inspection, Fasciola infected livers were increased in size, fibrosed, fatty, multiple white or reddish necrotic foci on the parietal surface, hard to cut, calcified, and numerous mature and immature flukes were also observed. In histoarchitecture, inflammatory cell infiltration in the hepatic parenchyma and periportal area, fibrous connective tissue proliferation around necrotic area, hyperplastic bile duct, congestion, and primary biliary cirrhosis were seen in acute and chronic fascioliasis. Epidemiological investigations revealed that fascioliasis was higher in goats than sheep. Age, sex, BCS and season were found to have statistically significant associations with fascioliasis in goats. In case of sheep, age (OR = 5.8671; 95% CI: 2.9482-11.6757, P < 0.0001), sex (OR = 3.7317; 95% CI: 1.9052-7.3094, p < 0.0001), BCS (OR = 6.0346; 95% CI: 1.7986-20.2472, p < .0001), and season (OR = 8.2308; 95% CI: 3.9922-16.9693, p = < .0001) were also found to have statistically significant associations with fascioliasis. Results of the study can help for molecular epidemiology of fascioliasis in small ruminants to plan fluke control programs for safe food production.

Keywords: Bangladesh; Epidemiology; Fascioliasis; Goat; Sheep; Slaughterhouse.

Fig. 1

Gross lesions of the livers of Fasciola infected goats and sheep. A Small size multiple white necrotic foci (arrows) and hemorrhages (asterisks) were seen on the parietal surface of the liver in acute fascioliasis. B Fatty liver of sheep bearing caseous fibrous nodule (arrow head) and fibrous tissue proliferation (asterisk) along with necrotic caseous mass (arrow). C Goat liver with fibrous nodule (arrow) at visceral surface and distended gall bladder (arrow head) which contains more than 10 flukes. D Sheep liver with cirrhosis (asterisks) and caseous nodule on parietal surface. E and F Pipe-stem liver of sheep and goat and fluke was found to escape following sectioning of the bile ducts of the liver (asterisk) in chronically Fasciola infection and hard calcareous mass (asterisks) and hyperplasia of bile duct opening (arrow). G Fibrous tissue proliferation around gall bladder (asterisk), numerous immature and adult liver flukes (arrow) and caseous necrotic nodule (arrowhead). H Flattened mature F. gigantica (arrow head) and immature F. gigantica flukes (asterisk) collected from gall bladder and bile ducts. Bar = 2.5 cm

Fig. 2

Histopathology of sheep and goat liver (H & E stained). A Infiltration of the inflammatory cell (asterisks) and a thin layer of connective tissue (arrow) around the portal area along with hyperplastic biliary duct (arrow head), B Extravascular congestion at the portal area (asterisks) with infiltration of inflammatory cells (arrow), C Classical features of chronic inflammation (identify) in the Fasciola infected liver including coagulative necrosis (arrow head), infiltration of inflammatory cells (asterisks) and fibrosis (arrow), D Primary biliary cirrhosis showing extensive proliferation of fibrous connective tissue (asterisks) around the intra-hepatic bile ductules with periportal infiltration of mononuclear inflammatory cells (arrow), E–F Hyperplasia of bile ducts (arrow head) surrounded by a thin layer of fibrous connective tissue (arrow), G Extensive proliferation of fibrous connective tissue (asterisks) and infiltration of inflammatory cells into the sinusoidal spaces, H Liver cirrhosis with granulomatous nodules in chronic Fasciola gigantica infection

Fig. 3

Prevalence of acute and chronic fascioliasis in sheep and goats along with histopathological lesions occurrences in sheep and goat in chronic fascioliasis