Protein complexes are involved in many vital biological processes. Therefore, researchers need these protein complexes for biochemical and biophysical studies. Several methods exist for expressing multi-subunit proteins in eukaryotic cells, such as 2A sequences, IRES, or intein. Nevertheless, each of these elements has several disadvantages that limit their usage. In this article, we suggest a new system for expressing multi-subunit proteins, which have several advantages over existing methods meanwhile it, lacks most of their disadvantages. Leishmania is a unicellular eukaryote and member of the Trypanosomatidae family. In the expression system of Leishmania, pre-long RNAs that contain several protein sequences transcribe. Then these long RNAs separate into mature mRNAs in the process named trans splicing. For producing multi-subunit protein, Leishmania transformed with a vector containing the sequences of all subunits. Therefore, those subunits translate and form the complex under eukaryotic cell conditions. The sequence of each protein must separate by the spatial sequence needed for trans splicing. Based on a Leishmania expression pattern, not only is it possible to produce the complexes with the correct structures and post-translational modifications, but also it is possible to overcome previous method problems.

Background: Blastocystis has been associated with various symptoms of the gastrointestinal tract. We aimed to investigate the prevalence of Blastocystis in children with celiac disease (CeD) or functional abdominal pain (FAP) and to evaluate its subtypes (STs) with respect to demographic, socioeconomic and epidemiological factors.

Methods: Overall, 161 fecal samples were collected from healthy children and patients with FAP or CeD in Hitit University Erol Olçok Research and Training Hospital, Corum, Turkey  between 2016-2018. Samples were examined using both native-Lugol (NL) and trichrome-stained (TS) smears, and further analyses by PCR and Sanger sequencing were performed. A standard questionnaire was applied to obtain demographic, socioeconomic, epidemiological data.

Results: Blastocystis was found in 10.6% of the total study population. Neither bacteria nor any other parasites were found, except for one Giardia (0.6%) in the CeD group. The presence/absence of the parasite was not found to be associated with demographic, socioeconomic and epidemiological factors. Blastocysis was detected in 11.5% (6/52) of the CeD, 7.7% (4/52) of the FAP, and 12.3% (7/57) of the healthy group. Diagnostic methods were similar in terms of Blastocystis detection (P= 0.671), and there was fair agreement between the NL, TS and PCR (Fleiss' Kappa=0.847, P=0.001). ST2 (42.8%) and ST3 (35.7%) were the predominant STs followed by ST1 (21.4%).

Conclusion: We observed no difference between study groups in terms of Blastocystis prevalence. ST1, ST2 and ST3 subtypes were detected. Blastocystis prevalence and STs were not related to any of the demographic, socioeconomic and epidemiological factors.

Background: Cystic echinococcosis (CE) is one of the most important parasitic infections in subgroup seven common neglected diseases of humans and animals. It is in the list of 18 neglected tropical diseases of the WHO. We aimed to analyze the situation of the disease in Iran using Geographical Information System (GIS) and satellite data analysis.

Methods: The data obtained from the Ministry of Health and Medical Education, Tehran, Iran and other related centers from 2009 to 2018 were analyzed using GIS. Then, the spatial distribution maps of the disease were generated, and the hot spots of the disease in Iran were determined using spatial analysis of ArcGIS10.5 software. Geographically weighted regression (GWR) analysis in ArcGIS10.5 was used to correlate the variables affecting the disease including temperature, relative humidity, normalized different vegetation index (NDVI) and incidence of hydatidosis. Data analysis was performed by Linear regression analysis and SPSS 21 software using descriptive statistics and chi-square test.

Results: Zanjan, Khorasan Razavi, North Khorasan, Chaharmahal Bakhtiari, Hamedan, Semnan, and Ardabil provinces were the hot spots of CE. The results of geographical weighted regression analysis showed that in Khorasan Razavi, North Khorasan, Chaharmahal Bakhtiari, Hamedan, Semnan, Ardabil, Zanjan, Qazvin, and Ilam provinces, the highest correlation between temperature, humidity, vegetation density and the incidence of hydatidosis was observed (P<0.001).

Conclusion: The use of maps could provide reliable estimates of at-risk populations. Climatic factors of temperature, humidity, NDVI had a greater impact on the probability of hydatidosis. These factors can be an indicator used to predict the presence of disease. Environmental and climatic factors were associated with echinococcosis.

Background: Visceral leishmaniasis (VL) caused by the Leishmania donovani complex that is transmitted by the bites of female sandflies. Mediterranean type of VL caused by L. infantum. While, Roudbar County of Guilan Province has been introduced as a suspected cutaneous leishmaniasis focus; there are no published data on the seroprevalence of VL in Guilan Province. We aimed to investigate the seroprevalence of this disease in Roudbar County.
Methods: This descriptive cross-sectional study was carried out in 2019-2020 among children less than 12 years of age to determine the seroprevalence of VL by direct agglutination test (DAT). Blood samples were randomly collected from 918 children under 12 years of age refers to the public health center in the clusters.
Results: Out of 918 children, 14 (1.52%) showed anti-Leishmania antibodies, with 4 (0.43%), 2 (0.21%), 8 (0.87%) anti-L. infantum antibodies at titers 1:800, 1:1600 and ≥1: 3200 respectively. All children with anti-Leishmania antibody titers of ≥1:800 were evaluated by a physician. Clinical manifestation of VL including fever, anemia and hepatosplenomegaly observed in a 6-year-old boy from Defraz village with anti-Leishmania antibody of titers ≥102400.This patient was admitted to the pediatric hospital in Rasht, capital of Guilan province, Iran and was successfully treated.
Conclusion: VL is being circulated with low prevalence in children up to 12 years old in Roudbar, northern part of Iran. Accordingly, it is critical to improve the awareness of physicians and public health supervisors about the importance of this fatal disease in Guilan province and especially in Roudbar area.

Background: Toxoplasmosis is a zoonotic disease caused by the parasite Toxoplasma gondii, a cosmopolitan intracellular parasite. It can be a risk factor for autoimmune diseases, including rheumatoid arthritis (RA). This study was designed to investigate the possible association between serological history of T. gondii infection and defined clinical manifestation of RA in Northeast of Iran.
Methods: Overall, serum samples were collected from 50 RA patients and 40 healthy controls, from Qaem Hospital in Mashhad City, northeastern Iran in 2018. Seroprevalence of T. gondii infection was determined by ELISA.
Results: The prevalence of anti -T. gondii IgG in RA patients 48% (24.50) was significantly higher than the control group 10% (4.40) (P <0.001). Erythrocyte sedimentation rate (ESR), anti-cyclic citrullinated peptide (anti-CCP) and (rheumatoid factor) RF levels between the RA and control groups (P <0.01). Control group were matched with patients for age, gender and living area.
Conclusion: Given that a high correlation has been demonstrated between positivity rate of anti-T. gondii IgG and RA in Northeastern Iran, further studies will be necessary to clarify the pathogenesis of T. gondii among these patients.

Background: Three of Taenia species, named Taenia saginata, T. solium and T. asiatica can be found in Indonesia, but only T. solium can lead to neurocysticercosis. The morphology of those 3 Taenia spp. egg is indistinguishable by standard parasitology procedure. We aimed to use Ziehl Neelsen staining for differentiation of eggs of T. saginata and T. solium.
Methods: As many as 40 containers of stool samples from the positive helminthiasis patients in Jakarta, Indonesia were collected during the year 2018. From each container, 10 slides prepared for staining with Kato-Katz technique as the preliminary examination. From those stool samples with positive taeniasis, we then once again made 10 slides/container for Ziehl Neelsen staining.
Results: The first 400 slides stained with Kato-Katz technique as preliminary test were all positive for Taenia spp. The second 400 slides, we got 244 slides that gave good results as we could distinguished between the eggs of T. saginata and T. solium, meanwhile the remainder 156 slides gave unconfirmed results. From those 244 slides, 154 slides showed T. saginata eggs with magenta colored and 90 slides showed T. solium eggs with blue/purple colored. The eggs of T. solium slightly smaller if compared to Taenia saginata and had round shape, meanwhile T. saginata eggs were oval in shape.
Conclusion: Ziehl Neelsen staining method can be used as an alternative parasitological method to differentiate the eggs of T. saginata and T. solium.

Background: Malaria parasites cause a tremendous burden of disease in both the tropics and subtropics areas. Growing of drugs resistance in parasites is one of the most threats to malaria control. The aim of study was to investigate the anti-malarial activity of nano-emodin isolated from Rhamnus cathartica on Plasmodium berghei in mice to evaluate parasites inhibition rate using in-vivo test.

Methods: The study was conducted in the School of Public Health, Tehran University of Medical Sciences, during 2020. Nano- emodin particles were prepared from Rhamnus cathartica, and confirmed by Zeta Potential Analyzer, DLS and electron microscopy techniques. Mice were infected with P. berghei and treated by emodin nanoparticles. Parasitemia was evaluated in each group in comparison with control group. Toxicity test was done using twice the highest concentration of emodin extract on a separate group of mice and ED50 was calculated.

Results: Emodin extract was significantly effective in all concentrations on D4 (P<0.05). The most effective on parasitemia was observed in 400 mg/kg of Liquid Nano-emodin and solid (non-Nano) emodin. ED50 for emodin extract was determined 220 mg/kg. Toxicity test showed no toxic effect on the subjects.

Conclusion: The emodin extract is safe, lack of side effects. So, it can be used for more and longer period of time and in higher doses. Emodin extract, either in form of liquid and nanoparticle or in a solid form, has the same therapeutic effect on P. berghei in infected Balb/c mice.

Background: Detection of Leishmania RNA virus (LRV) in Old World Leishmania species and their possible role in the disease prognosis requires sensitive and specific methods, preferably independent of the viral genome. We aimed to develop an indirect immunofluorescence antibody (IFA) assay to detect LRV in the Old World Leishmania parasites.
Methods: Clinical samples were collected from 86 cutaneous leishmaniasis (CL) patients in different endemic areas of CL in Iran, during 2017-2019. For antibody preparation, the viruses were obtained from sediment of an LRV-infected L. major culture-using freeze and thaw cycles followed by gradient cesium chloride centrifugation. The purified viruses were used to immunize a male 3-4 months rabbit. Various dilutions of the LRV-immunized rabbit's serum and a conjugated antibody were deployed to detect LRV in 48 isolates by IFA assay.
Results: LRV virus was detected in four of the 48 CL cases using IFA method. Amplification of a partial fragment of RNA-dependent RNA polymerase (RdRp) gene from the isolates confirmed the IFA results. In phylogeny, the generated RdRp sequences from four isolates were grouped with the other Old World LRVs, but separate from L. aethiopica LRVs, which appeared as a highly supported distinct clade.
Conclusion: Further optimization of this approach to detect the LRV directly in lesion scrapings can make it a more reliable tool for field studies and disclosing the virus's possible role in disseminating and unusual clinical features.

Background: Cystic echinococcosis (CE) is an important zoonotic parasitic disease worldwide. Application of species-specific antigen for serodiagnosis of human CE has not been utilized, so far. In this regard, AgB originated from Echinococcus granulosus sensu stricto (G1-G3) and E. canadensis (G6/G7) CE cysts, confirmed by molecular biology and sequencing was used for evaluation of their ability in the diagnosis of confirmed human CE.Methods: The hydatid cyst fluid (HCF) of E. granulosus sensu stricto and E. canadensis species were separately,
used for preparation of AgB during 2017-2018 in Shiraz and Tehran, Iran. A total of 45 sera samples from confirmed CE patients, 102 sera from healthy people as negative control and 44 sera from other parasitic diseases, were used for measurement of the diagnostic ability of antigen B originated from E. granulosus sensu stricto and E. canadensis species of CE, alone or in 50%:50% mixture using ELISA method.
Results: Overall, 38 (84.4%) out of 45 confirmed human CE were positive by ELISA using AgB originated from E. granulosus sensu stricto. This items for AgB originated from E. canadensis was 39 (86.6) out of 45 serum samples. A total of 39 out of 45 samples (86.6%) showed positivity by a mixture of antigen B originating from both species. The specificity of the above tests was calculated as 93.15%, 96.58%, and 93.84%, respectively.
Conclusion:  Due to the diversity of the cyst species in human population, application of AgB from prevalent species alone or in combination with other species is suggested.

Background: We aimed to investigate the prevalence of Cryptosporidium species detected in humans and calves in the Van region of Turkey.
Methods: A total of 150 patients, comprising 60 who were immunosuppressed, 50 who were immunosuppressed and had diarrhea, and 40 who had only diarrhea, were enrolled in this study in the Department of Medical Parasitology, Van Yuzuncu Yıl University Faculty of Medicine, Turkey. Stool samples were taken from the rectums of a total of 50 calves that had 30 diarrhea and 20 that did not have diarrhea, from the stables and farms of 10 central villages of Van, Turkey. All samples were analyzed using modified acid-fast staining, immunochromatographic test, and PCR. Cryptosporidium positive samples were also subtyped.
Results: Only C. parvum subtypes were detected in all positive samples. C. parvum was detected in 30 (20%) of the 150 human stool samples, while it was detected in 5 (10%) of the 50 samples from the calves. The GP60 gene region was amplified and sent for sequence analysis to identify the C. parvum subtypes.
Conclusion: As a result, C. parvum is found to be an active species that caused cryptosporidiosis is in the Van region. IIdA24G1 subtype of C. parvum were found in both human and calf. Therefore, due to the zoonotic feature of the C. parvum IIdA24G1 subtype, it has been shown that the calves in the region are a significant risk for humans.

Background: In previous studies, a new Trichinella spiralis serine protease 1.1 (TsSP1.1) was identified in surface proteins of T. spiralis muscle larvae (ML) by proteomics analysis, but its functions in T. spiralis infection are unknown. The aim of this study was to investigate the roles of TsSP1.1 during larval intrusion of gut epithelium.
Methods: From January 2019 to March 2021, complete TsSP1.1 cDNA sequence was cloned and expressed in Escherichia coli BL21 at the Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, China. Expression and location of TsSP1.1 in the parasite were investigated using indirect immunofluorescence assay (IIFA) and Western blotting. The in vitro intestinal epithelium cells (IECs) intrusion assay was used to ascertain the roles of TsSP1.1 during larval intrusion of IECs and gut epithelium.
Results: TsSP1.1 was a surface and secretory protein, which was expressed at various T. spiralis stages, and principally localized at cuticle, stichosome and embryos of the nematode. rTsSP1.1 accelerated larval intrusion of IECs, whereas anti-rTsSP1.1 antibodies impeded larval intrusion. The acceleration and inhibtion was dose-dependently related to rTsSP1.1 and anti-TsSP1.1 antibodies. Block of the IIL with anti-rTsSP1.1 serum also impeded larval intrusion of gut mucosa.
Conclusion: TsSP1.1 participates in T. spiralis intrusion of gut epithelium.

Background: Intestinal parasitic infections (IPIs) are still considered a public health problem of mankind, particularly in immunocompromised patients. We aimed to determine the prevalence of IPIs with an emphasis on immunocompromised patients in a referral hospital in Tehran Province, Iran.

Methods: In this cross-sectional study, 442 fecal specimens were collected randomly from patients, referred to Baqiyatallah Hospital in Tehran Province, Iran from May to September 2020. The collected specimens were examined using wet-mount, trichrome and modified Ziehl-Neelsen staining, formalin-ether concentration, and agar plate culture.

Results: The prevalence of IPIs was found 17.0% (95% CI: 13.6-20.8%). The prevalence of protozoan parasites (16.3%; 95% CI: 13.0-20.1%) was significantly higher than helminthic parasites (0.7%; 95% CI: 0.1-2.0%). Blastocystis spp., Giardia lamblia, and Entamoeba coli were the most common intestinal protozoan with a prevalence of 12.2%, 1.6%, and 1.4%, respectively. E. histolytica/E. dispar/E.  moshkovskii, Iodamoeba bütschlii, Cryptosporidium spp., Chilomastix mesnili as protozoan species and Hymenolepis nana, Dicrocoelium dendriticum, and Ascaris lumbricoides as helminthic species were the other detected parasites. Multiple logistic regression revealed a significant association of IPIs infections with stool consistency and the status of immune system.

Conclusion: The prevalence of IPIs among the patients who are immunocompromised was significantly higher than immunocompetent patients (P< 0.05). Periodic stool examinations for screening of IPIs should be included as a part of routine medical check-up in these patients.

Background: Dermatoparasitic infestations due to the mites Demodex spp. and Sarcoptes scabie are prevalent dermatological disorders worldwide.

Methods: Referral patients from the Departments of Dermatology, Infectious Diseases, and from the psychologists, in some cases, to the laboratory of Medical Helminthology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran were examined and documented for demodicosis and scabies from March 2009 to December 2020. All patients’ data were collected and then analyzed statistically by SDATA version 14, using the Chi-square test.

Results: Out of 494-suspected patients suffering from dermal disorders, 99 patients (20.04%) and 20 cases (4.04%) were found infested with demodicosis and scabies, respectively. Most demodicosis cases belonged to the 46-60 year age group while the infestation rate of scabies was higher in the age group under 5 years (

Background: Sparganosis is a zoonotic disease caused by Plerocercoid larvae (spargana) of the genus Spirometra. We aimed to provide molecular evidence for the infection of amphibians with Spirometra sp. in the inside and outside of Horton Plains National Park (HPNP), Sri Lanka.

Methods: The prevalence of sparganum infection in wild frogs (Truga eques and Minverya agricola) was investigated in the inside and outside of HPNP from June 2019 to April 2021.A total of 1,434 Amphibians samples were surveyed to examine the spargana infection from the study site. To identify the species identity of the collected spargana, a portion of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and nuclear 18S rRNA gene were amplified, sequenced, and analyzed.

Results: A total of 539 infected amphibians (T. eques and M.  agricola) samples were examined to survey from the study area. Spargana were detected in all dissected specimens belonging to the species Spirometra erinaceieuropaei that were genetically confirmed using the evolutionary conserved nuclear 18S rRNA gene and then compared to the GenBank deposit, indicating that S. erinaceieuropaei is the primary causal agent of sparganosis both inside and outside the HPNP.

Conclusion: Our finding is the first genetically confirmed record of S. erinaceieuropaei in amphibians in South Asia. However, further studies are needed to investigate the prevalence of sparagna infection in amphibians all over the island.

Background: Paragonimiasis presents with nonspecific symptoms and radiologic findings, allowing for the possibility of misdiagnosis. Diagnosis is generally delayed due to lack of suspicion and presentation similar to pulmonary tuberculosis.

Methods: A prospective observational study was carried out on 20 subjects at Civil Service Hospital of Nepal from March 2015 to June 2019 who presented with eosinophilia and pulmonary symptoms, and were treated empirically with Anti-tubercular therapy for suspicion of pulmonary tuberculosis.

Results: The median age of the patient was 34 years. Mean blood absolute eosinophil count was 16678/ul. Fever was present in 80% (n=16). Cough was present in 90% (n=18). Pleural effusion was noticed in 100% (n=20). Chest computed tomography showed ground-glass opacities in 65% (n=13) of patients. Pleural fluid eosinophilia (>10%) was evident in all patients. Pleural fluid LDH was elevated in 85% (n=17) of patients. Similarly, ADA was high (>40U) in 75% (n= 15) of patients, and pleural fluid sugar was low in 80% (n=16) of patients. All patients (100%) gave a history of crab or snail consumption. Paragonimus egg was detected in five (25%) patients. Twenty patients fulfilled definite or probable diagnostic criteria of paragonimiasis. Ninety-five (n=19) patients responded to praziquantel.

Conclusion: Unavailability of serologic tests or failure to demonstrate parasitic egg under the microscope should not discourage physicians to consider the diagnosis of paragonimiasis when marked eosinophilia, high LDH levels, and low glucose levels are identified in pleural fluid of a patient with a history of raw crab or snail consumption.

We report a case of Hymenolepis diminuta infection in a two years old boy living in Guilan Province, northern Iran diagnosed in 2019. The patient was complained of anorexia, weight loss, weakness and disturbed sleep. Stool examination revealed numerous eggs of H. diminuta. After treatment with a single dose of oral praziquantel, the patient recovered without evidence of the egg shedding in follow-up stool samples. Moreover, we performed detailed phylogenetic analysis of the H. diminuta comparing with other isolates deposited in GenBank database based on Cox1 gene. Based on BLAST analysis of Cox1 gene our sequence showed 97.4-99.2% similarity with those of H. diminuta available in GenBank. The present study recommends the importance of reporting the infection cases, in order to improve knowledge on epidemiology and control of the neglected disease.

Malaria is a multilateral parasitic infection, which causes wonderful mortality and morbidity worldwide. It sometimes accompanied a quaint appearance. An Iranian 50-year-old man was admitted to Omid, hospital, a specialized cancer hospital in Isfahan, Iran. Because of a 15-year persisted anemia due to misdiagnose of vivax malaria led him to three courses of anticancer chemotherapy and splenectomy. His blood smears were sent to the Department of Parasitology, School of Medicine, Isfahan University of Medical Sciences, Iran. Our findings from his history, file documents, clinical signs and symptoms, and parasitological and molecular assessments revealed an interesting case, which is reported.

Hydatid cyst is a parasitic infection transmitted by oral ingestion of Echinococcus granulosus eggs. Hydatid cyst of the genital tract is rare and the occurrence in the uterus is an extreme rarity. We present an 8-yr-old girl with complaints of swelling of lower abdomen, pollakiuria and bilateral flank pain was brought to Emergency Department of Harran University, Turkey, in Jun 2019. The patient had simultaneous hydatid cysts of the liver, mesentery and uterus. We performed abdominal exploration and completely removed the inner germinal layer of cyst through an incision made in the anterior of the uterine fundus. Then, we applied total excision to the two cysts in the right and left colon mesentery. Finally, we performed partial cystectomy to the cyst in the liver, and we removed the cyst membrane totally. In endemic regions, hydatid cysts should be considered for the diagnosis of children with cystic mass lesions. Uterine-sparing approach should be kept in mind as an option, especially in young women. Early surgical treatment of large pelvic cysts that cause obstructive uropathy may prevent the progression of renal damage.

The differential diagnosis of bloody diarrhea is necessary to specify etiology and plan treatment. Misdiagnosis can lead to catastrophic results with the treatments to be given.  In this case report, we present a case of schistosomal colitis mimicking ulcerative colitis in a 26-year-old Guinean male patient diagnosed in 2021.

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