Histopathological and Immunohistochemical Study of Lambs Experimentally Infected with Fasciola hepatica and Schistosoma bovis

Abstract

Summary The aim of this study was to investigate the cross‐resistance between Fasciola hepatica and Schistosoma bovis in lambs assessing parasitologic, gross pathologic, histopathologic and immunohistochemical changes in liver and small intestine. Thirty Castellana breed lambs were divided into five comparable groups and exposed to F. hepatica/S. bovis (group F/S), S. bovis/F. hepatica (group S/F), S. bovis (group S) or F. hepatica (group F) and six unexposed lambs were used as non‐infected controls (group C). Primary patent infection with F. hepatica induced a lower number of schistosome eggs and a higher number of lymphocytes in intestinal and liver schistosome egg‐induced granulomas in group F/S than in the groups S/F and S, liver damage being mainly attributed to F. hepatica. S. bovis infection followed by challenge with F. hepatica particularly increased the severity of the most significant liver alterations (cholangiohepatitis by F. hepatica and mesoendophlebitis by S. bovis) and F. hepatica seemed not to have an influence on established S. bovis infection. In addition, immunohistochemical results suggested that the predominant local immune response in both double‐infected groups was different, being mainly a cell‐mediated immune response in group F/S and a mucosal response in group S/F.

Concurrent infections ofFasciola,SchistosomaandAmphistomumspp. in cattle from Kafue and Zambezi river basins of Zambia

“…Since both trematodes cause significant liver pathology (Ferreras et al, 2000;Phiri et al, 2006b), when one infection is established, it may exclude the other from establishing. Since both trematodes cause significant liver pathology (Ferreras et al, 2000;Phiri et al, 2006b), when one infection is established, it may exclude the other from establishing.…”

“…Since both trematodes cause significant liver pathology (Ferreras et al, 2000;Phiri et al, 2006b), when one infection is established, it may exclude the other from establishing. In experimental studies, primary infection with Schistosoma or Fasciola species in ruminants has been reported to result in enhanced resistance to heterologous challenge (Bushara et al, 1978;Sirag et al, 1981;Yagi et al, 1986;Ferreras et al, 2000;Almeida et al, 2003). Although the correlation coefficient between the two trematodes in our study was negative, the relationship was not significant (P ¼ 0.390).…”

“…Although the correlation coefficient between the two trematodes in our study was negative, the relationship was not significant ( P = 0.390). In experimental studies, primary infection with Schistosoma or Fasciola species in ruminants has been reported to result in enhanced resistance to heterologous challenge (Bushara et al , 1978; Sirag et al , 1981; Yagi et al , 1986; Ferreras et al , 2000; Almeida et al , 2003). Our findings however, were not conclusive, since this study was done in naturally infected cattle from endemic areas with no known duration of infections.…”

A prospective view of animal and human Fasciolosis

“…In addition, it has been shown that M2 macrophages isolated from mice during infection with F. hepatica promote the polarization of Th2 cells (69,70). Thirdly, there is a significant increase in the number of mast cells observed at the site of infection and in the gut mucosa (73)(74)(75)(76)(77). While mast cells are critical to the expulsion of gut helminths (78), their role in Fasciola infection is not clear, although we hypothesize that given that mast cells have an important role in wound healing and tissue remodelling (79), they are recruited to combat the extensive tissue damage caused by migratory flukes (80).…”

Mast cells: new therapeutic target in helminth immune modulation

“…Similarly, mast cells are observed in the chronic stages of Schistosoma infection, when T H 2/T reg immune responses are predominant , again implicating an important role for mast cells in shaping the adaptive immune response. Increased mast cell infiltration in the liver remains a key feature of Fasciola hepatica infection , and in rodent models, this is dominated by T H 2/T reg responses within hours of infection.…”