Background: Giardiasis is considered as one of the most prevalent gastrointestinal parasitic infections
worldwide. Most of the used anti-Giardia drugs may cause side effects and are often associated with
clinical failure and drug resistance. Prebiotic and probiotic therapy has been posited as potential natural
therapeutic agent for many parasitic diseases.
Objective: To evaluate the effect of combined prebiotic and probiotic therapy as a natural supplement and
after addition to nitazoxanide (NTZ) in treatment of giardiasis in murine model.
Material and Methods: Ninety-six laboratory bred Swiss albino male mice were used. Mice were divided
into three main groups that included 16 subgroups (6 mice each). Control group (A1-7) included control
negative (non-infected non-treated), control positive (infected non-treated), and another five control
subgroups (SGs) that received natural prebiotic and probiotic supplements and NTZ. Prophylactic group (B)
included three SGs in which infected mice received prebiotic and probiotic separately and in combination
for one week before infection and continued till the end of experiment. Infected treated group (C1-6)
composed of six infected SGs that received treatment by prebiotic and probiotic separately, and combined
prebiotic/probiotic, NTZ alone (full dose), and after addition of combined supplement to NTZ (half or
full dose). Evaluation was achieved using parasitological, histopathological, immunohistochemical, and
immunological parameters.
Results: There was significant reduction of Giardia cyst shedding in all prophylactic and infected treated
SGs. The highest mean cyst reduction was observed in group C after addition of combined supplement
to NTZ post infection (PI) and in group B receiving prophylactic combined supplement. Remarkable
improvement of histopathological findings was observed especially in group C after receiving combined
supplement in addition to NTZ, followed by other prophylactic and infected treated SGs. The results
of immunohistochemical caspase 3 expression revealed that combined supplement was effective in
preventing apoptotic cell death of intestinal cells that is induced by giardiasis especially after addition of
combined supplement to NTZ in group C. Immunological assessment of interleukin-6 (IL-6) level showed
significant increase in all treated SGs with boosted elevation in combined supplement after addition to
NTZ in group C.
Conclusion: Combined prebiotic and probiotic products can be considered as good prophylactic and
therapeutic agents when added to NTZ against giardiasis.