Background: Diagnosis of microsporidiosis is difficult due to its small size needing special stains and identification by an expert. Nowadays, application of polymerase chain reaction (PCR) made diagnosis more sensitive, specific and easier. Objectives: To update the prevalence of intestinal microsporidia and to clarify their genotype patterns in symptomatic and asymptomatic immune compromised and immune competent cases. Patients and Methods: Totally, 323 stool samples were collected and subdivided as 173 from immune compromised (group I) and 150 from immune competent (group II) individuals. Samples were examined for microsporidiosis by light microscopy smears stained by Weber's modified trichrome (WMT) and modified Ziehl Neelsen (MZN), as well as by nested and RFLP PCR techniques. Results: Microsporidial spores were microscopically detected in 45/323 (13.9%) individuals; 25/173 (14.5%) immune compromised and 20/150 (13.3%) immune competent cases. In the two groups, 25/45 (55.6%) were symptomatic complaining of diarrhea, abdominal pain, distension, mal-digestion and weight loss, with statistical significant difference (P<0.001) between infection and presence of symptoms. Nested and RFLP PCR missed only one positive case, thus scoring 97.8% sensitivity and 100% specificity, positive predictive value 100%, negative predictive value 99.6% and diagnostic accuracy 97.8%. In group I, 5 cases were associated with Enterocytozoon (Ent.) bieneusi, 5 with Encephalitozoon (Enc.) species and 15 had mixed infection. In group II, 6 had Ent. bieneusi, 3 had Enc. species and 10 had mixed infection. Sequencing of the internal transcribed spacer of rDNA of five samples demonstrated the Ent. bieneusi anthroponotic genotype B and the zoonotic potential for genotypes D and K, in addition to one Enc. intestinalis sequence. Conclusion: Prevalence of microsporidiosis was insignificantly higher in immune compromised than immune competent population. Intestinal microsporidiosis can be manifested by different abdominal symptoms or it can be asymptomatic. PCR technique highlighted that mixed infection with Ent. bieneusi and Encephalitozoon species was the commonest finding among the studied groups. Ent. bieneusi genotypes appeared to be related to animal contact and human infection. This, however, could not be accurately defined due to the limited number of available sequences.

The aim of the present work was to design praziquantel (PZQ) loaded chitosan nanoparticles (PZQ-Cs) to improve the oral bioavailability and overcome the drawbacks of conventional PZQ therapy. The synthesized chitosan nanoparticles (CsNPs) were physico-chemically characterized by TEM and dynamic light scattering (DLS) with the calculation of the encapsulation efficiency (EE). PZQ was loaded into CsNPs in three different doses; reduced dose (250 mg/kg), high dose (500 mg/kg) and fully effective dose (1000 mg/ kg). Infected treated groups received either oral PZQ-Cs or oral PZQ alone 42 days post-infection and were sacrificed 2 weeks post-treatment. The current study revealed that PZQ-Cs induced a significant anti-schistosomal effect, compared to the infected non-treated control. However, on comparison with conventional PZQ treatment at the corresponding doses, oral PZQ-Cs showed a lower anti-schistosomal potential as reflected by the total worm burden, tissue ova count and oogram pattern. PZQ-Cs was significantly effective in attenuating the oxidative insult associated with S. mansoni infection, compared to the infected non-treated and PZQ treated groups. Genotoxicity assessment proved the safety of CsNPs, as they did not induce a significant DNA fragmentation in non-infected mice treated with blank CsNPs. The present work highlights CsNPs as safe, effective anti-inflammatory and antioxidant agents that could find a clinical use in the treatment of schistosomiasis induced oxidative stress and hepatic dysfunction. Further studies are recommended, however, to investigate how PZQ-Cs could be further modified to increase its anti-schistosomal potential.

No abstract