Toxoplasma gondii vaccine candidates: a concise review.

Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis. It has been shown that the severity of symptoms depends on the functioning of the host immune system. Although T. gondii infection typically does not lead to severe disease in healthy people and after infection, it induces a stable immunity, but it can contribute to severe and even lethal Toxoplasmosis in immunocompromised individuals (AIDS, bone marrow transplant and neoplasia). The antigens that have been proposed to be used in vaccine candidate in various studies include surface antigens and secretory excretions that have been synthesized and evaluated in different studies. In some studies, secretory antigens play an important role in stimulating the host immune response. Various antigens such as SAG, GRA, ROP, ROM, and MAG have been from different strains of T. gondii have been synthesized and their protective effects have been evaluated in animal models in different vaccine platforms including recombinant antigens, nanoparticles, and DNA vaccine. Four bibliographic databases including Science Direct, PubMed Central (PMC), Scopus, and Google Scholar were searched for articles published up to 2020.The current review article focuses on recent studies on the use and usefulness of recombinant antigens, nanoparticles, and DNA vaccines.

Nephrotoxicity of Albendazole and Albendazole Loaded Solid Lipid Nanoparticles in Mice with Experimental Hydatidosis.

Purpose: Cystic echinococcosis (CE) is a serious contemporary public health problem. Different CE treatment methods are of considerable importance, with albendazole (ABZ) being one of the most preferred drugs for CE treatment and prophylaxis. In this study, we evaluated the nephrotoxicity caused by ABZ and ABZ-loaded solid lipid nanoparticles (SLNs) in mice with experimental hydatid cyst. Methods: ABZ-loaded SLNs were produced by micro-emulsification and a high shear homogenization technique. Thereafter, we evaluated the physicochemical characterization of the product. Live protoscolices were injected into mice to induce experimental hydatidosis. Mice were then treated with ABZ and ABZ-loaded SLNs. The nephrotoxicity effects were evaluated by biochemical and histopathological surveys. Results: Significantly different blood urea nitrogen (BUN) levels were observed between the two infected groups (ABZ treatment and ABZ-loaded SLN treatment) and the control group. The kidney malondialdehyde (MDA) and glutathione (GSH) levels of the infected groups were not significantly different from those of the control group. The histopathological study revealed nephropathic and pathologic changes in the ABZ and ABZ-loaded SLN groups. Conclusion: ABZ formulated for ABZ-loaded SLNs had a more prominent chemoprophylactic efficacy on CE and fewer side effects than ABZ alone. Neither ABZ nor ABZ-loaded SLNs caused significant biochemical and histopathological defects on the kidney, and all functional biochemical markers stayed within the normal range. Therefore, ABZ-loaded SLNs could be a potential new product for CE treatment.

Prevalence of Intestinal Parasitic Infections Among Diarrheic Patients from Ahvaz, Southwestern Iran.

BACKGROUND: Intestinal parasitic infections are among the most common infections in humans, particularly in resource-poor communities. Gastrointestinal parasites, specially protozoa, can lead to diarrhea, malabsorption, and anemia. The majority of parasitic diarrhea is caused by Entamoeba histolytica, Giardia duodenalis, and Cryptosporidium spp. The present study aimed to evaluate the prevalence of intestinal parasites among diarrheic patients referred to the Shahid Rajaee Polyclinic, Ahvaz, southwestern Iran. METHODS: A cross-sectional study was conducted to determine the prevalence of intestinal parasites among 250 diarrheic patients using direct smear, formalin-ether concentration, Ziehl-Neelsen and trichrome staining. RESULTS: The results indicated that 34.4% (86/250) of the patients were infected with pathogenic parasites. Giardia duodenalis with an occurrence of 18.8% (47/250) and Cryptosporidium spp. with a frequency of 2.8% (7/250) had the highest and lowest infection rates, respectively. Blastocystis hominis with a frequency of 15.2% (38/250) showed the highest prevalence rate after G. duodenalis. Entamoeba histolytica/dispar was observed in 3 (1.2%) of diarrheic patients. The age group 1-10 years old was the most frequently infected group (27.9%). We could not find a significant association between the source of drinking water and intestinal parasitic infections (p= 0.912). CONCLUSION: This study demonstrated that G. duodenalis was the predominant parasite found among the patients. The results revealed that intestinal parasites were one of the main health problems in the region.

Gene migration for re-emerging amebiasis in Iran's northwest-Iraq borders: a microevolutionary scale for reflecting epidemiological drift of Entamoeba histolytica metapopulations.

In the microevolutionary scales of Entamoeba isolates, the gene migration shows how Entamoeba spp. has epidemiologically drifted among border countries. Five hundred fecal samples were taken from patients suffering gastrointestinal disorders, abdominal pain, and diarrhea at Saggez, northwest Iran located within the border Iraq country. Following parasitological techniques, DNA samples were extracted and amplified by polymerase chain reaction (PCR) of 18S rRNA region to identify Entamoeba infections. To distinguish the Entamoeba spp., a multiplex PCR was conducted. Amplicons were sequenced to reconfirm their heterogeneity traits and phylogenetic analysis. Additionally, Entamoeba histolytica sequences of Iraq were retrieved from GenBank database. The suspected isolates were diagnosed as E. histolytica (2.2 %), Entamoeba moshkovskii (1 %), and Entamoeba dispar (0.4 %). Mixed Entamoeba infections did not detect among isolates. A parsimonious network of the sequence haplotypes displayed star-like features in the overall isolates containing E.h1, E.d2, and E.m3 as the most common haplotypes. According to analysis of molecular variance (AMOVA) test, high partial value of haplotype diversity (0.700 to 0.800) of E. histolytica was shown the total genetic variability within populations while nucleotide diversity was low among Iranian and Iraqi metapopulations. Neutrality indices of the 18S rRNA were shown negative values in E. histolytica populations which indicating significant deviations from neutrality. A pairwise fixation index (F-statistics [Fst]) as a degree of gene flow had a low value for all populations (0.001) while the number of migrants was 2.48. The statistically Fst value indicates that E. histolytica isolates are not genetically differentiated among shared isolates of Iran and Iraq. Occurrence of E.h1 between two regional populations indicates that there is dawn of Entamoeba flow due to transfer of alleles from one population to another population through host mobility and ecological alterations. To evaluate the hypothetical evolutionary scenario, further study is required to analyze Entamoeba spp. in the neighboring Middle East countries.