The immunomodulatory activity of secnidazole-nitazoxanide in a murine cryptosporidiosis model

Introduction. Cryptosporidium parvum causes intestinal parasitic infections affecting both immunosuppressed and immunocompetent individuals.Gap statement. Given the absence of effective treatments for cryptosporidiosis, especially in immunodeficient patients, the present study was designed to assess the therapeutic efficacy of secnidazole (SEC) and its combination with nitazoxanide (NTZ) in comparison to single NTZ treatment in relation to the immune status of a murine model of C. parvum infection.Methodology. The infected groups were administered NTZ, SEC or NTZ-SEC for three or five successive doses. At days 10 and 12 post-infection (p.i.), the mice were sacrificed, and the efficacy of the applied drugs was evaluated by comparing the histopathological alterations in ileum and measuring the T helper Th1 (interferon gamma; IFN-γ), Th2 [interleukin (IL)-4 and IL-10] and Th17 (IL-17) cytokine profiles in serum.Results. The NTZ-SEC combination recorded the maximal reduction of C. parvum oocyst shedding, endogenous stages count and intestinal histopathology, regardless of the immune status of the infected mice. The efficacy of NTZ-SEC was dependent on the period of administration, as the 5 day-based treatment protocol was also more effective than the 3 day-based one in terms of immunocompetence and immunosuppression. The present treatment schedule induced an immunomodulatory effect from SEC that developed a protective immune response against C. parvum infection with reduced production of serum IL-17, IFN-γ, IL-4 and IL-10.Conclusions. Application of NTZ-SEC combined therapy may be useful in treatment of C. parvum, especially in cases involving immunosuppression.

Encapsulation of Low Metronidazole Dose in Poly (D,L-lactide-co-glycolide) (PLGA) Nanoparticles Improves Giardia intestinalis Treatment

Background

The present study was designed to investigate the antigiardial efficacy of low metronidazole dose loaded-D.L-lactide-co-glycolide (LMD-PLGA) nanoparticles (NPs) and to compare it with the standard high dose of metronidazole either free (HMD) or loaded on PLGA (HMD-PLGA).

Materials and Methods

PLGA NPs were prepared by single emulsification method, metronidazole (MTZ) was loaded in low and high doses. The nanoparticles were evaluated in vivo for mice model. The Giardia intestinalis infected mice were treated by LMD and HMD either free or PLGA NPs loaded, the parasitic load and ployclonal antigiardial serum antibodies (IgG and IgA) were recorded. Histopathological studies on intestinal and liver sections were applied.

Results

MTZ-PLGA NPs was successfully prepared with 81.68% encapsulation efficiency and with an average particle size of approximately 228.00 ± 43.19 nm and -32.28 ± 0.07 mV Zeta potential. Experimentally, it was observed that Giardia intestinalis infected animals administered with LMD-PLGA had completely eliminated cyst shedding and trophozoite count compared with Giardia-infected mice. Further, it was found that animals belonging to LMD-PLGA group had significantly reduced levels of antigiardial IgA (0.99 ± 0.05) antibodies in serum compared with Giardia-infected. Histopathologyically, also animals belonging to LMD-PLGA treated group had intact mucosal epithelium lining, and normal villi with no detection of G. intestinalis trophozoites. In addition to the less toxic effect on the liver tissue compared to free HMD, HMD-PLGA and infected-untreated groups using Ishak grading system.

Conclusion

Our study showed that PLGA nanoparticles could be atrial delivery systems for antigiardial drugs to improve their therapeutic efficacy and minimize their side effects that results from frequent dosing.

Protection against Fasciola gigantica using paramyosin antigen as a candidate for vaccine production

Yet no vaccine to protect ruminants against liver fluke infection has been commercialized. In an attempt to develop a suitable vaccine against Fasciola gigantica (F. gigantica) infection in rabbits, using 97 kDa Pmy antigen. It was found that, the mean worm burdens and bile egg count after challenge were reduced significantly by 58.40 and 61.40%, respectively. On the other hand, immunization of rabbits with Pmy induced a significant expression of humoral antibodies (IgM, total IgG, IgG1, IgG2 and IgG4) and different cytokines (IL-6, IL-10, L-12 and TNF-alpha). Among Ig isotypes, IgG2 and IgG4 were most dominant Post-infection (PI) while, recording a low IgG1 level. The dominance of IgG2 and IgG4 suggested late T helper1 (Th1) involvement in rabbit's cellular response. While, the low IgG1 level suggested Th2 response to adult F. gigantica worm Pmy. Among all cytokines, IL-10 was the highest in rabbits immunized with Pmy PI suggesting also the enhancement of Th2 response. It was clear that the native F. gigantica Pmy is considered as a relevant candidate for vaccination against fascioliasis. Also, these data suggested the immunoprophylactic effect of the native F. gigantica Pmy which is mediated by a mixed Th1/Th2 response.

Evaluation of the diagnostic potential of different immunological techniques using polyclonal antibodies against Fasciola gigantica excretory/secretory antigens in sheep

The early detection of Fasciola antigens (Ags) in serum or stool could be more valuable in diagnosis as early treatment would be applied before irreparable damage occurs. In this study, fresh adult Fasciola gigantica (F. gigantica) worms were cultivated for 16 hrs. Excretory/secretory (E/S) Ags were extracted from the culturemedium and used to raise rabbit antibodies (Abs) to Fasciola. The purified Abs were then used in sandwich ELISA (S-ELISA) to detect Fasciola Ags in serum and stool samples from a total of 152 sheep, and sandwich-Dot-ELISA (S-D-ELISA) for the serum samples. Gross inspection of liver for flukes or other parasites was performed and results of parasitological stool examination were recorded. Accordingly, sheep were divided into healthy control group (25 sheep), Fasciola positive group (97 sheep) and other helminthic infection groups (30 sheep). S-ELISA for serum samples showed 91.9% sensitivity and 89% specificity. Fasciola Ags, detected in serum of sheep by S-D-ELISA, showed 97.2% sensitivity and 95% specificity and coproantigens detected by S-ELISA, showed 95.8% sensitivity and 92.7% specificity. Although, the specificity of stool examination was higher than that recorded for serum, the sensitivity of ELISA techniques to diagnose Fasciola Ags was higher than that recorded for parasitological examination. It is concluded that, S-D-ELISA has better sensitivity and specificity than S-ELISA for both stool and serum, and may prove useful for field applications.