Parasitic infection of livers and lungs in cattle and sheep in Constantine slaughterhouses, Algeria, in 2009-2018

A retrospective study was carried out from registers of the slaughterhouses of Constantine, Algeria, on 145,919 cattle and 345,282 sheep apparently healthy, slaughtered between 2009 and 2018. The objective was to estimate the prevalence of the two dominant parasitic infections which cause gross lesions in liver and lungs, i.e. cystic echinococcosis (CE) and Fasciola hepatica infection. The postmortem examination consisted in a visual inspection of the organs, palpation of lungs and livers, and systematic incision of livers, performed according to FAO procedures. The prevalence of F. hepatica infection was significantly higher in cattle (2.7%) than in sheep (0.2%). There was a non-significant decrease from 4.5 to 2.0% (p > 0.05) in the prevalence of F. hepatica in cattle during the 10-year period. The prevalence of CE in the livers and lungs was significantly higher in cattle (3.3% and 9.7%, respectively) than in sheep (0.6% and 1.1%, respectively). The prevalence of CE was significantly higher in lungs than in livers. These results showed the importance of these parasitic infections in the province of Constantine and its surroundings, which requires the implementation of control programs against these infections in both sheep and cattle.

Timing of transcriptomic peripheral blood mononuclear cell responses of sheep to Fasciola hepatica infection differs from those of cattle, reflecting different disease phenotypes

Infection with the zoonotic trematode Fasciola hepatica, common in many regions with a temperate climate, leads to delayed growth and loss of productivity in cattle, while infection in sheep can have more severe effects, potentially leading to death. Previous transcriptomic analyses revealed upregulation of TGFB1, cell death and Toll-like receptor signalling, T-cell activation, and inhibition of nitric oxide production in macrophages in response to infection. However, the differences between ovine and bovine responses have not yet been explored. The objective of this study was to further investigate the transcriptomic response of ovine peripheral blood mononuclear cells (PBMC) to F. hepatica infection, and to elucidate the differences between ovine and bovine PBMC responses. Sixteen male Merino sheep were randomly assigned to infected or control groups (n = 8 per group) and orally infected with 120 F. hepatica metacercariae. Transcriptomic data was generated from PBMC at 0, 2 and 16 weeks post-infection (wpi), and analysed for differentially expressed (DE) genes between infected and control animals at each time point (analysis 1), and for each group relative to time 0 (analysis 2). Analysis 2 was then compared to a similar study performed previously on bovine PBMC. A total of 453 DE genes were found at 2 wpi, and 2 DE genes at 16 wpi (FDR < 0.1, analysis 1). Significantly overrepresented biological pathways at 2 wpi included role of PKR in interferon induction and anti-viral response, death receptor signalling and RIG-I-like receptor signalling, which suggested that an activation of innate response to intracellular nucleic acids and inhibition of cellular apoptosis were taking place. Comparison of analysis 2 with the previous bovine transcriptomic study revealed that anti-inflammatory response pathways which were significantly overrepresented in the acute phase in cattle, including IL-10 signalling, Th2 pathway, and Th1 and Th2 activation were upregulated only in the chronic phase in sheep. We propose that the earlier activation of anti-inflammatory responses in cattle, as compared with sheep, may be related to the general absence of acute clinical signs in cattle. These findings offer scope for smart vaccination strategies for this important livestock parasite.

Combined effects of Fasciola hepatica infection and copper intoxication on oxidative/antioxidative status in rats

The aim of our study was to investigate parameters of oxidative/antioxidative status in rats experimentally infected with Fasciola hepatica and treated with a copper salt. The experiment was carried out on 24 male Wistar albino rats, divided into 4 groups with 6 animals in each: group 1 – healthy untreated animals, group 2 – rats orally infected with F. hepatica; group 3 – rats treated with CuSO4. 5H2O and group 4 – rats experimentally infected with F. hepatica and treated with CuSO4.5H2O. Rats from group 2 and 4 were orally infected with 15 viable F. hepatica metacercariae per animal. Rats from group 3 and 4 received CuSO4.5H2O dissolved in drinking water at a dose of 150 mg/kg body weight after post infestation week 2. Copper administration lasted 2 weeks. The rats were euthanised on the 35th day post infestation. The levels of malondialdehyde, glutathione, and the activity of Cu, Zn-superoxide dismutase and glutathione peroxidase in the liver of all rats were established. Increased liver MDA level was observed in groups infected and untreated with copper compared to control level. Reduced Cu,Zn-SOD activity was found in all infected rats as well as insignificant increase of the enzyme in group 3 compared to control group value. GPx activity was reduced in similar manner in the treated and infected groups compared to the control group. GSH level was lower in all treated rats than in controls (P<0.01). Copper liver content was increased in groups receiving CuSO4.5H2O compared both to control and infected only group. Substantial imbalance in oxidative/antioxidative status in groups 2, 3 and 4 was demonstrated compared to the control group. Combined effect of chronic copper administration and experimental F. hepatica infection increased significantly MDA level, reduced the activity of Cu,Zn-SOD and the GSH content in host livers. Elevated copper level influenced defense system in F. hepatica infected rats at a high extent. Parasites and copper acted together to increase the oxidative stress. Parasitism in the presence of copper pollution compromises the health of the host, even at low intensities.