A systematic review on the role of GRA proteins of Toxoplasma gondii in host immunization.

Toxoplasma gondii is a widespread obligatory intracellular parasite infecting humans and most of all other warm-blooded animals. Currently there is no any accepted vaccine for prevention of T. gondii infection. Many studies are focused on using of various excretory secretory antigens (ESA); and among them dense granule antigens (GRAs) being involved in parasite survival, virulence and replication processes, are considered as one of the predominant vaccine candidates. The aim of this systematic review is to prepare more comprehensive understanding of these antigens to reduce T. gondii infection in humans and animals. English databases, including PubMed, Science Direct, Google Scholar, Scopus, ISI Web of Science were systematically searched and papers evaluating GRA antigens published until June 2019 were selected. Evaluation of selected publications revealed that GRA4 and GRA7 substantially increased survival time of the experimental animals. It is noticeable that the maximum reduction in cyst burden was observed in BALB/c mice vaccinated with combination of GRA3, GRA7 and M2AP antigens (93.5%). GRA6 and GRA10 have shown high immunogenicity and GRA1 and 2 are important for virulence and induction of immune responses. This review will be helpful for researchers to conduct more effective studies in the field of immunization against T. gondii infection.

A systematic review of Toxoplasma gondii antigens to find the best vaccine candidates for immunization.

At present, there is not any available accepted vaccine for prevention of Toxoplasma gondii (T. gondii) in human and animals. We conducted literature search through English (Google Scholar, PubMed, Science Direct, Scopus, EBSCO, ISI Web of Science) scientific paper databases to find the best vaccine candidates against toxoplasmosis among T. gondii antigens. Articles with information on infective stage, pathogenicity, immunogenicity and characterization of antigens were selected. We considered that the ideal and significant vaccines should include different antigens and been expressed in all infective stages of the parasite with a high pathogenicity and immunogenicity. Evaluation within this systematic review indicates that MIC 3, 4, 13, ROP 2, RON 5, GRA 1, 6, 8, 14 are expressed in all three infective stages and have pathogenicity and immunogenicity. MIC 5, ROM 4, GRA 2, 4, 15, ROP 5, 16, 17, 38, RON 4, MIC 1, GRA 10, 12, 16, SAG 3 are expressed in only tachyzoites and bradyzoites stages of T. gondii with pathogenicity/immunogenicity. Some antigens appeared to be expressed in a single stage (tachyzoites) but have high pathogenicity and induce immune response. They include enolase2 (ENO2), SAG 1, SAG5D, HSP 70, ROM 1, ROM 5, AMA 1, ROP 18, RON2 and GRA 24. In conclusion, current vaccination against T. gondii infection is not satisfactory, and with the increasing number of high-risk individuals, the development of an effective and safe specific vaccine is greatly valuable for toxoplasmosis prevention. This systematic review reveals prepare candidates for immunization studies.

A cross-sectional analysis of intestinal parasitic infections among the general population in north of Iran.

INTRODUCTION: Intestinal parasitic infection (IPIs) is one of the most important health problems in the developing countries. Study on the prevalence of IPIs in various communities is a prerequisite for the development of appropriate control strategies. The aim of this study was to evaluate the prevalence of intestinal parasites among the general population in Mazandaran province, northern Iran. METHODOLOGY: This study was conducted on 4,788 specimens collected from 17 urban areas (2,515 samples) and 34 rural areas (2,273 samples) within January-December 2016. Fecal specimens were examined by direct wet mounting, formalin-ether concentration, modified Ziehl-Neelsen, and trichrome staining methods. RESULTS: The overall infection rate of intestinal parasite was 14.2% (680/ 4,788). Blastocystis hominis and Giardia lamblia were identified as the most frequent parasites. Protozoa, helminths, and polyparasitism (co-infections with two or more parasite species) were observed in 12.3%, 1.03%, and 0.85% of the specimens, respectively. Furthermore, IPIs showed a significant association with household income, place of residence, washing of vegetables, exposure to soil and season (p < 0.05). CONCLUSIONS: Based on the findings, parasitic infections are still a major public health concern in the north of Iran that requires special attention. Therefore, the major key to success in the prevention of IPIs is the execution of some interventions, including patient screening and treatment, public education, and improvement of sanitary conditions.

Molecular Cloning, Expression and Characterization of Plasmid Encoding Rhomboid 4 (ROM4) of Tachyzoite of Toxoplasma gondii RH Strain.

BACKGROUND: The objective of this study was to clone, express and characterize the gene encoding rhomboid 4 (ROM4) proteins, a vital gene in surface adhesion and host cell invasion process of tachyzoite of T. gondii in an appropriate expression vector and eukaryotic cell for production of recombinant protein. METHODS: Toxoplasma RNA was isolated from tachyzoites (RH strain) and complementary DNA was synthesized. Oligonucleotide primer pair was designed based on Toxoplasma ROM4 gene sequence with XhoI and EcoRI restriction sites at 5' end of forward and reverse primers, respectively. ROM4 gene was amplified by PCR, cloned into pTG19-T vector and the recombinant plasmid was sequenced. The gene was subcloned into pcDNA3 plasmid and expressed in CHO cells as eukaryotic cell. SDS-PAGE and western blotting were performed for protein determination and verification. RESULTS: Cloning of ROM4 gene in pTG19-T vector was confirmed by colony-PCR and enzymatic digestion. The results of enzymatic digestion and gene sequencing confirmed successful cloning and subcloning procedures. The nucleotide sequence of the cloned ROM4 gene showed 99% homology compared to the corresponding sequences of original gene. SDS-PAGE and western blotting analyses of the purified protein revealed a single band having expected size of 65 kDa. CONCLUSION: This eukaryotic expression system is an appropriate system for high-level recombinant protein production of ROM4 gene from T. gondii tachyzoites used as antigenic component for serological assay and vaccine development.

Immunological evaluation of a DNA cocktail vaccine with co-delivery of calcium phosphate nanoparticles (CaPNs) against the Toxoplasma gondii RH strain in BALB/c mice.

Many recent studies have been conducted to evaluate protective immunity mediated by DNA vaccines against toxoplasmosis. Cocktail DNA vaccines showed better immune responses compared to single vaccines. The objective of the current study was to evaluate the protective efficacy of rhomboid 4 (ROM4) and cocktail DNA vaccines (ROM4 + GRA14) of the Toxoplasma gondii RH strain with or without coated calcium phosphate nanoparticles (CaPNs) as the adjuvant to improve the immunogenicity against the T. gondii RH strain in BALB/c mice. Cocktail DNA vaccines of pcROM4 + pcGRA14 of the T. gondii RH strain were constructed. CaPNs were synthesized and the cocktail DNA vaccine was coated with the adjuvant of CaPNs. Immunogenicity and the protective effects of cocktail DNA vaccines with or without CaPNs against lethal challenge were evaluated in BALB/c mice. pcROM4 and cocktail DNA vaccine coated with CaPNs significantly enhanced cellular and humoral immune responses against Toxoplasma compared to pcROM4 and cocktail DNA vaccine without CaPNs (p < 0.05). These findings indicate that the survival time of immunized mice after challenge with the RH strain of T. gondii was increased compared to that of controls and the DNA vaccine provided significant protection in mice (p < 0.05). The CaPN-based cocktail DNA vaccine of pcROM4 + pcGRA14 showed the longest survival time compared to the other groups. Co-immunization with CaPN-based cocktail DNA vaccine (pcROM4 + pcGRA14) boosted immune responses and increased the protective efficacy against acute toxoplasmosis in BALB/c mice compared to both single gene and bivalent DNA vaccine without nano-adjuvants.

Domestic dog as a human health hazard in north of Iran.

An epidemiological study was conducted to determine the prevalence of helminthic parasites of domestic dogs using stool samples in north of Iran in 2013. Stool samples (n = 100) were collected from domestic dogs of different ages and genders. Different techniques including wet smear, formalin-ether sedimentation method and flotation technique in saturated zinc chloride solution were performed on collected stools to detect eggs and larval stage of helminthes parasites. The overall prevalence of helminthic parasites of examined stools of dogs was 57 %. The examined domestic dogs harbored eggs of eight species of helminthes including: Taenia spp., Diyplidium caninum, Toxocara canis, Toxascaris leonina, Capillaria aerophila, Mesostesphanus spp. and Trichuris volpis. T. canis and T. volpis were the most and least prevalent eggs, respectively. No significant statistical differences were observed between infection by helminthic parasites and both gender and age of the dogs (P > 0.05). Considering high level of helminthic infection in the stool of examined domestic dogs, a contiguous educational program to increase awareness of dog owners and an effective anti-parasite control programmed is highly recommended in order to reduce the danger of zoonotic diseases in north of Iran. This is the first report of C. aerophila and Mesostesphanus spp. from dog in Iran.

The efficacy of herbal medicines against Toxoplasma gondii during the last 3 decades: a systematic review.

The objective of the current study was to systematically review papers discussing the efficacy of medicinal herbs against Toxoplasma gondii. Data were systematically collected from published papers about the efficacy of herbs used against T. gondii globally from 1988 to 2015, from PubMed, Google Scholar, ISI Web of Science, EBSCO, Science Direct, and Scopus. Forty-nine papers were included in the current systematic review reporting the evaluation of medicinal plants against T. gondii globally, both in vitro and in vivo. Sixty-one plants were evaluated. Most of the studies were carried out on Artemisia annua. The second highest number of studies were carried out on Glycyrrhiza glabra extracts. RH and ME49 were the predominant parasite strains used. Additionally, Swiss-Webster and BALB/c mice were the major animal models used. Alcoholic and aqueous extracts were used more than other types of extracts. Natural compounds mentioned here may be developed as novel and more effective therapeutic agents that improve the treatment of toxoplasmosis due to their lower side effects, higher availability, and better cultural acceptance compared with those of the chemical drugs that are currently being used.

Cats and Toxoplasma gondii: A systematic review and meta-analysis in Iran.

Toxoplasma gondii is a cosmopolitan zoonotic intracellular coccidian of the phylum Apicomplexa infecting warm-blooded animals and human beings. This protozoan causes a significant public health problem in humans and imposes considerable economic losses and damages to husbandry industries. The final host, cats, accounts for all of these significant burdens. Hence the present study was designed to analyse and review the overall prevalence rate of T. gondii infection in cats in Iran for the first time. In the present study data collection (published and unpublished papers, abstracts of proceedings of national parasitology congresses and dissertations) was systematically undertaken on electronic databases including PubMed, Google Scholar, Ebsco, Science Direct, Scopus, Magiran, Irandoc, IranMedex and Scientific Information Database. A total of 21 studies from 1975 to 2013 reporting prevalence of Toxoplasma infection in cats from different areas in Iran met the eligibility criteria. The pooled proportion of toxoplasmosis using the random-effect model amongst cats was estimated at 33.6% (95% confidence interval [CI] 22.05-46.41). The prevalence rate of cat toxoplasmosis in various regions of Iran ranged from 1.2% to 89.2%. Firstly, this study establishes a crude prevalence rate of T. gondii infection in cats. Secondly, it discusses the role of significant risk factors including sex, age and being either household or stray cats, in the epidemiology of the disease. Furthermore, the current study determines gaps and drawbacks in the prior studies that are useful to keep in mind to assist in designing more accurate investigations in future.

Cattle toxoplasmosis in Iran: a systematic review and meta-analysis.

OBJECTIVE: To analyze and review the overall seroprevalence rate of Toxoplasma gondii (T. gondii) infection in cattle from Iran. METHODS: In the current study, data collection (published and unpublished papers, abstracts of national scientific congresses and dissertations) using particular terms was carried out systematically on the following electronic databases like PubMed, Google Scholar, Ebsco, Science Direct, Scopus, Magiran, Irandoc, IranMedex and SID (Scientific Information Database). RESULTS: A total of 22 studies since 1983 to 2012 reporting the seroprevalence of toxoplasmosis in cattle from different regions of Iran met our eligibility criteria. The pooled proportion of toxoplasmosis, using random effect model, among cattle in Iran from over the 30-year period was estimated 18.1% (95% CI: 9.9% to 28.2%). CONCLUSIONS: This study firstly establishes a crude seroprevalence rate of Toxoplasma infection in cattle which can lead us to understand the condition of cattle toxoplasmosis, which have to take into accounted for an appropriate and effective prevention and controls. Secondly, it compares and discusses elaborately the role of risk factors including sex, age and breed in the epidemiology of the disease. Thus, it determines gaps and drawbacks in the prior studies which are greatly useful to design more accurate investigations in the future.

Cattle toxoplasmosis in Iran：a systematic review and meta-analysis

Objective:To analyze and review the overall seroprevalence rate ofToxoplasma gondii(T. gondii) infection in cattle fromIran.Methods:In the current study, data collection(published and unpublished papers, abstracts of national scientific congresses and dissertations) using particular terms was carried out systematically on the following electronic databases like PubMed,GoogleScholar,Ebsco,ScienceDirect,Scopus,Magiran,Irandoc,IranMedex andSID (ScientificInformationDatabase).Results:A total of22 studies since1983 to2012 reporting the seroprevalence of toxoplasmosis in cattle from different regions ofIran met our eligibility criteria.The pooled proportion of toxoplasmosis, using random effect model, among cattle inIran from over the30-year period was estimated18.1%(95%CI:9.9% to28.2%) .Conclusions:This study firstly establishes a crude seroprevalence rate ofToxoplasmainfection in cattle which can lead us to understand the condition of cattle toxoplasmosis, which have to take into accounted for an appropriate and effective prevention and controls.Secondly, it compares and discusses elaborately the role of risk factors including sex, age and breed in the epidemiology of the disease.Thus, it determines gaps and drawbacks in the prior studies which are greatly useful to design more accurate investigations in the future.

Toxoplasmosis in immunocompromised patients in Iran: a systematic review and meta-analysis.

Although toxoplasmosis in immunocompetent individuals is generally asymptomatic, in immunocompromised patients (HIV/AIDS, cancer, and transplant patients), it can lead to serious pathological effects. This study included a systematic review and meta-analysis to comprehensively assess the seroprevalence rate of Toxoplasma infection in immunocompromised patients in Iran. Electronic English and Persian databases (PubMed, Google Scholar, ScienceDirect, Scopus, Magiran, Scientific Information Database [SID], IranMedex, and IranDoc), parasitology congresses, and projects and theses of Iranian medical universities, were systematically searched from 1997 to 2013 (published or unpublished data). In this paper, several studies that used serological methods for diagnosis of toxoplasmosis were selected. Analysis of seroprevalence estimates was pooled using a random-effects meta-analysis. Twenty-two studies, comprising 2,805 individuals, were included in the meta-analysis. Overall seroprevalence rate of Toxoplasma infection in Iranian immunocompromised patients was 50.01% (95% confidence interval, 43.85 to 56.17); however, there was significant heterogeneity among study groups. The results showed that seroprevalence rate of toxoplasmosis among transplant recipients, HIV/AIDS, and cancer patients in Iran was 55.1%, 50.05%, and 45.06%, respectively. In addition, IgM seroprevalence rate was estimated to be 4.85% (95% confidence interval, 2.22 to 8.41). This systematic review and meta-analysis identified a high seroprevalence rate of Toxoplasma infection among immunocompromised patients (50%). Consideration of management, design and provision of appropriate control measures of toxoplasmosis is highly recommended.