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Objectives :

Cryptosporidium spp and Giardia duodenalis are two protists responsible for enteritis in mammals. They are highly resistant in the external environment. They mainly cause neonatal diarrhoea in ruminants (cryptosporidiosis) and chronic diarrhoea in young domestic animals (giardiosis). Many species of Cryptosporidium and certain genotypes (assemblages) of Giardia duodenalis are zoonotic. They infect the enterocytes of the small intestine (surface infection for Giardia and epicellular infection for Cryptosporidium).

I- The research carried out in our group on these two parasites, which are important both economically and in terms of public health, is based on host-parasite interactions, the development of experimental models (in vitro and in vivo) and their use for therapeutic screening and the evaluation of alternatives to anti-parasitic chemotherapy.

II- Molecular characterisation of Cryptosporidium spp and Giardia duodenalis isolates circulating in farm animals (cattle, sheep, goats) is another major focus of our work in the laboratory.

Cryptosporidian oocysts detected by the modified Ziehl-Neelsen technique (magnification X 100)

(Credit : JRU BIPAR, ENVA)

Cryptosporidian oocysts (small oocysts) and Giardia cysts (large cysts) detected by the direct immunofluorescence technique

(Source: www.cdc.gov, USA)

Charolais calf with cryptosporidiosis and severe diarrhoea

(Credit : JRU BIPAR, ENVA).

Major results:

I- There is little data on the presence of Cryptosporidium spp and Giardia duodenalis in sheep in Algeria, or their potential role as zoonotic reservoirs. The aim of this study, carried out as part of a PhD thesis, is to investigate the presence and distribution of these two parasites in lambs. The presence of families of zoonotic subtypes of C. parvum (IIa, IId) and C. ubiquitum, as well as the zoonotic assemblage of G. duodenalis A+E, indicates that sheep could play an important role as a potential reservoir for zoonotic protists. Similar work has been carried out on cryptosporidiosis in sheep and cattle in France and has been the subject of 2 publications in 2019.

Molecular characterization of zoonotic Cryptosporidium spp and Giardia duodenalis pathogens in Algerian sheep. 2019, Sahraoui et al.,  Veterinary Parasitology : Regional Studies and Reports

First identification of Cryptosporidium parvum zoonotic subtype IIaA15G2R1 in diarrheal lambs in France. 2019, Mammeri et al., Veterinary Parasitology : Regional Studies and Reports

Molecular characterization of Cryptosporidium isolates from diarrheal dairy calves in France. 2019, Mammeri et al., Veterinary Parasitology : Regional Studies and Reports

II- We characterised the impact of C. parvum infection on the kid microbiome. C. parvum was administered orally to healthy animals and infection showed a decrease in butyrate biosynthetic pathways in the kid microbiome. Our results suggest that intestinal inflammation induced by C. parvum infection is associated with a reduction in butyrate-producing bacteria. This finding could serve as a basis for developing new control strategies to improve ruminant health.

Cryptosporidium parvum infection depletes butyrate producer bacteria in goat kid microbiome. 2020, Mammeri et al., Frontiers in Microbiology

III- lmpact of G. duodenalis infection on the development of the host gut microbiota. We assessed the impact of G. duodenalis infection on the development of the canine gut microbiota. The faecal microbiota of puppies became more complex and less diverse with age, dominated at the end of the study by 4 phyla: Bacteroidota, Firmicutes, Fusobacteriota and Proteobacteria. The dysbiosis associated with G. duodenalis was characterised by an enrichment in facultative anaerobic, mucus-degrading, pro-inflammatory species and opportunistic pathogens, as well as a reduction in Lactobacillus johnsonii at specific times during the study. Calprotectin was also monitored during this study and its level increased with age suggesting the establishment of chronic low-grade inflammation in puppies.

Age and Giardia intestinalis infection impact canine gut microbiota. 2021, Boucard et al., Microorganisms

Current projects:

• Project PARADISE :

Concerning Cryptosporidium, since 2019 we have been part of a European consortium (Paradise: parasites diseases) with different workshops (WP) that aim to take stock of knowledge and genomic data on Cryptosporidium and Giardia. The laboratory is involved in WP3 and WP4. We are involved in the development of aptamers to improve the detection of cryptosporidia and giardia in food. We will also be testing nanobodies produced in Germany to demonstrate their potential effectiveness in detecting cryptosporidia.

• Project AMI (PARAVIR) :

Participation of the "Crypto-Giardia" group as a partner in the "Transversalités inter-laboratoires et autres directions de l'ANSES" call for expressions of interest. "PARAVIR project: detection of parasite viruses" co-piloted by Gregory Karadjian (BIPAR JRU, LSAn) and Nolwenn Dheilly (VIRO JRU, LSAn).

Collaborations :

• Controlling Giardia using probiotics and studying antiparasitic mechanism: collaborative project (DIM1 Health) with Isabelle Florent from UMR7245 (CNRS-MNHN, Sorbonne Universités).
• Project PARAVIR :  detection of viruses and parasites: in collaboration with Nolwenn Dheilly (JRU VIRO LSAn).
• Project PREZODE on the molecular epidemiology of cryptosporidia and giardia in farm animals (focus on comparative genomics): Pr Lihua Xiao (College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China).
• Project « Molecular epidemiology of cryptosporidia in animals in North Africa » : Dr Djamel Baroudi et Dr Lynda Sahraoui, Ecole nationale supérieure vétérinaire d’Alger.