Iranian Journal of Parasitology
Volume:18 Issue: 2, Apr-Jun 2023

 We aimed to present a systematic review and meta-analysis of studies that used antigen-based assays for the diagnosis of human giardiasis.

 All the related published literature cited within PubMed, ISI web of science, Google Scholar, Embase, and Scopus, were searched up to December 2021. The search terms, both as MeSH terms and text words, were “Giardia”, “Giardia lamblia”, “Giardia intestinalis", "giardiasis", combined with "diagnosis", "antigen detection", serodiagnosis, or serological diagnosis.  The required data was extracted from the papers. Pooled estimates of sensitivity and specificity were obtained and forest plots and summary receiver operating characteristics (SROC) plots were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). 

 The search of databases found 1683 papers, of which 46 articles fulfilled our eligibility criteria. The sensitivity of antigen-based methods for the diagnosis of human giardiasis ranged from 45% (95% CI: 31-59%) to 100% (95% CI: 100-100%) and the pooled estimate of sensitivity was 92% (95% CI: 90-93%). The pooled estimated specificity was 97% (95% CI: 96-98%), ranged from 81% (95% CI: 68-89%) to 100% (95% CI: 98-100%). The summary estimate of PPV and NPV were 92 % (95% CI: 90-93%) and 97% (95% CI: 96-98%) respectively. Comparing the performance of the antigen detection assays by region revealed a significant difference in the assay's performances in different regions of the world.

 The antigen-based detection methods have acceptable and satisfactory performance in the diagnosis of human giardiasis.  The task ahead is to identify more specific target antigens and design simpler, cheaper, and more sensitive methods for the diagnosis of this common worldwide-distributed parasitic infection.

Leishmaniasis is currently considered a re-emerging or emerging infection based on the geographic region. The outcome of leishmaniasis vastly depends on Leishmaniahost interaction. This preliminary study aimed to show the association of human leukocyte antigen (HLA) class I and II genes with healed and non-healed cutaneous leishmaniasis (CL), and symptomatic and asymptomatic visceral leishmaniasis (VL) compared with control groups in Iran.

Ninety-five people, including 31 patients versus 64 individuals in the control group, were enrolled. Among them, 20 patients had confirmed CL based on amastigote observation, 10 had improved CL and 10 non-healed CL. Eleven patients were suffering from confirmed VL based on direct agglutination test (Five asymptomatic and six symptomatic VL cases). Besides, they were residents in an endemic area of VL in the northwest of Iran. To select a control group, it was ensured that they had no history of leishmaniasis. Peripheral blood samples were collected from each patient. After DNA extraction, HLA typing was conducted using polymerase chain reaction - sequence-specific priming (PCR-SSP). Subsequently, data were statistically analyzed by SPSS.

There was a statistical relationship between the presence of HLA-A26 and CL, healed CL and the existence of the B38 allele, C1 allele and symptomatic VL, as well as B1.4 allele and asymptomatic VL (P˂0.05).

This primary finding indicates that several HLA genes have a potential role in the susceptibility of Iranian people to CL and VL.

Currently, there are conflicting reports on the associations between Toxoplasma gondii infection and multiple sclerosis (MS) in humans. In the present study, a case–control study was carried out to assess associations between seropositivity to T. gondii infection and MS.

This case-control study was carried out on 200 MS patients (cases) attended in Sina Hospital affiliated to Tehran University of Medical Sciences, Tehran, Iran, and 200 healthy subjects from the general population of the same city, March to July 2017. Blood samples were collected from individuals and were examined using Enzyme-linked immunosorbent assay (ELISA) for the presence of T. gondii IgG antibodies and the IgG-positive samples were further analyzed for specific anti-T. gondii IgM.

The overall seroprevalence of anti-T. gondii IgG was 44.2% (177/400) in 121 (60.5%) sera of the 200 MS patients (cases) and 56 (28.0%) sera of the 200 controls (OR = 3.94; 95% CI: 2.59–5.99; P < 0.001). Seroprevalence of T. gondii infection in MS patients increased significantly with increasing of age (P < 0.001). In the control group, no statistically significant differences were seen between the seroprevalence of T. gondii infection in various age groups (P = 0.858). Moreover, no statistically significant relationships were reported between the seropositivity to T. gondii and the sex for the cases and controls (P>0.05). Anti-T. gondii IgM antibodies were not detected in anti-T. gondii IgG positive patients.

T. gondii infection might be a probability risk factor for MS. However, further studies are necessary to describe clearly the roles of T. gondii infection in MS.

Toxoplasma gondii coinfection can modify host immune responses and the severity and spread of other parasites. We investigated how T. gondii and Trichinella spiralis infections counter-regulate each other's immune responses.

The parasite burden, the expression of T. gondii rhoptry kinase ROP18 and T. spiralis putative serine protease (TsSP), the IgG1 and IgG2a responses, besides histopathological and immunohistochemical staining with iNOS and arginase were used to evaluate the dynamics of coinfection.

Through their effects on host immune responsiveness, coinfection with T. gondii modified the virulence of T. spiralis infection. Coinfected animals with high and low doses of T. gondii demonstrated significant reductions in the T. spiralis burden of 75.2% and 68.2%, respectively. TsSP expression was downregulated in both groups by 96.2% and 86.7%, whereasROP18 expression was downregulated by only 6% and10.6%, respectively. In coinfected mice, elevated levels of T. gondii-specific IgG2a antibodies were detected. Th1 induced by T. gondii inhibits the Th2 response to T. spiralis in coinfected animals with high iNOS expression andlow-arginine1 expression.

T. gondii infection induces a shift toward a Th1-type immune response while suppressing a helminth-specific Th2 immune response, paving the way for developing novel vaccines and more efficient control strategies.

Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques.

The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank.

Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups.

Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management.

Dicrocoelium dendriticum, a worldwide zoonotic trematode, is a common parasite of ruminant animals, but humans can be the definitive host by chance. We analyzed the world situation of the parasite from the perspective of the One Health concept by analyzing the research literature published from 1931 to 2022.

Published documents related to D. dendriticum were searched from the Scopus database. Focusing on a visual analysis of the main research documents on D. dendriticum, Dimensions free web app was used to conduct co-occurrence analysis with keywords, countries, institutions, and authors. Moreover, key clustering research, affiliaitons, journals, countries, and authors were determined.

The Higher Council for Scientific Research (CSIC) was the most publishing affiliation on D. dendriticum with 19 articles. While the Veterinary Parasitology Journal was the mostly publishing journal on D. dendriticum with 38 articles, the most productive country was Iran. The authors Giuseppe Cringoli and Laura Rinaldi from Università degli Studi di Napoli Federico II, Naples, Italy were the mostly publishing authors.

This bibliometric analysis provides an overall description of the current state of D. dendriticum research and the initial exploration of future research directions. Our analysis provides guidance for the development of research on D. dendriticum.

We aimed to determine the frequency and subtype of B. hominis in diabetic patients.

One hundred and fifty diabetic patients and 100 healthy people without any chronic disease were included in the study. Stool samples were analyzed by native-Lugol, condensation, trichrome staining and PCR methods.

İn 150 patients with diabetes; B. hominis was detected in 38 (25.3%) by PCR, in 34 (22.7%) by native-Lugol and trichrome staining. In the control group, 14 (14%) out of 100 subjects were positive by PCR, and 10 (10%) were positive by native-Lugol and trichrome staining. In the statistical evaluation, a significant difference was found between gender (P=0.023), age (P=0.045; ≤35 and >35 comparison), duration of diabetes (P=0.04), the HbA1c value (P=0.023; <8 and ≥8 comparison), and B. hominis positivity. ST1 was determined in 76.9% of patients with diabetes, and ST2 was determined in 23.07%. Considering the 3 methods, B. hominis positivity was detected in 40 patients (26.7%) in diabetic group and in 14 participants (14%) in the control group (P=0.011).

B. hominis is a factor to be considered in patients with diabetes. Herein, the most common subtype detected in the patients with diabetes mellitus was ST1, but this result was not considered sufficient to reveal the importance of the subtype factor in the pathogenicity of B. hominis in patients with diabetes. In this context, there is a need for more comprehensive studies in both diabetic and other immunocompromised patient groups.

Human cysticercosis (CC) is a global public health problem, especially in Latin America, including Brazil. We aimed to analyze the seroprevalence of CC among school-age children and adolescents.

We analyzed the presence of specific IgG antibodies against Taenia solium metacestodes in 500 serum samples from elementary school children and adolescents in Jataí City, state of Goiás, Brazil. IgG antibodies against the antigenic extract of the parasite were detected and analyzed by ELISA, and specific peptides were identified by confirmatory Western Blotting test.

Of the 500 study participants, 205 (41%) were male, and 295 (59%) were female. Participants aged between 4 and 18 years (mean age 8.4 years). The percentage of serum samples reactive by ELISA was 37.2%. These samples were analyzed by Western Blotting, which confirmed that the seropositivity rate was 6.2% (95% CI 2.4–14.7) in 31 samples reactive for CC-specific bands, determined in serum samples from 18 male (5–11 years old) and 13 female (4–12 years old) students.

The CC seroprevalence demonstrated in schoolchildren suggests that this parasitosis is endemic in the study area. Further investigations are necessary to clarify the local epidemiology of this parasitosis.

Toxoplasmosis is a parasitic disease caused by compilation protozoan agent Toxoplasma gondii, leading to significant financial and quality-adjusted life-year losses. Overcooked or raw meat consumption has been a considerable transmission route. The present study was conducted to determine the seropositivity rate of T. gondii in sheep and goats by serological and molecular tests and genotyping of obtained isolates in northeast Iran.

Blood and tissue samples (diaphragm, heart) of 296 animals (including 168 sheep and 128 goats) were collected from the slaughterhouse in Quchan Country from august 2016 to April 2017. Modified agglutination test (MAT) and the PCR method performed to detect parasite DNA on tissues.PCR-RFLP method of GRA6 gene was used to determine the genotype of T. gondii. In addition, sequencing analysis was performed to evaluate the Toxoplasma type strains.

Serum positive for MAT results were found in 27.4% of sheep and 23.4% of goats. Positive PCR of B1 gene results in diaphragm and heart tissues of sheep and goats was 47.8% and 26.1%, 40% and 23.3%, respectively. PCR of GRA6 gene results were positive in 10 samples that RFLP technique results using MseІ enzyme revealed genotype І. Sequencing and phylogenetic analysis revealed DNA of all samples was closely related to Toxoplasma type І.

Concerning the high seropositivity rate of toxoplasmosis, undertaking an appropriate preventive program for reducing the prevalence of T. gondii infection by raw or undercooked meat consumption of livestock is recommended. Our study supports the notion that these animals' consumption of raw and undercooked meat can be a probable source of human toxoplasmosis.

Visceral leishmaniasis (Kala-azar) is an inherently dangerous and progressive disease that can be seen in many parts of the world, including Iran. Therefore, we decided to conduct this study on children with Kala-azar in Rasht-Iran.

In this descriptive study, the hospital records of all children with Kala-azar disease admitted to 17 Shahrivar Hospital, Rasht- Iran from 2009 to 2021 were reviewed. Required information were collected from patients' records and descriptive statistical analysis was done using SPSS version 24 statistical software.

A total of 22 children with visceral leishmaniasis were admitted to 17 Shahrivar Hospital during the study period. The average age of the children was 2.93 ± 3.32 years. Most of them (59.1%) were boys and lived in the foothills (59.1%). The most common season for children to get the disease was spring (45.5%), and the average duration of the disease until hospitalization was 16.5 ± 13.54 days. In this study, the most common clinical manifestations included fever (90.9%), splenomegaly (77.3%), hepatomegaly (50%), weakness and restlessness (27.3%), and vomiting (18.2%). The most common laboratory findings were anemia (90.9%), leukopenia (59.1%), increased erythrocyte sedimentation rate (ESR) (75%), and increased C-reactive protein (CRP) (75%). 72.7% of the children were treated with liposomal amphotericin and others with glucantime, which were all successful.

The results of our studies were consistent with most studies in Iran and other countries. These findings can help in the diagnosis and management of children with Kalaazar and better control of the disease in the province.

We aimed to investigate the frequency of Demodex infestation and clinical implications in connective tissue disease patients with facial erythema.

Patients diagnosed with a connective tissue disease and had facial erythema were consecutively enrolled in the study from 2019-2020. An age and gender matched control group was formed from healthy volunteers. Presence of Demodex was investigated by standardized skin surface biopsy. Number of Demodex mites over 5 per centimeter square was considered meaningful for infestation. Topical or systemic metronidazole treatment was given to the connective tissue disease patients with Demodex infestation. Facial erythema visual analog scale was questioned in patients at treatment onset and one month after.

A total of 31 connective tissue disease patients with facial erythema were enrolled. Control group included 31 healthy volunteers. Demographics and comorbidities were similar between groups. Demodex infestation was present in 58.1% of the disease group and in 25.8% of the control group (P=0.01). Pruritus was the most common symptom in patients with infestation. Median (IQR) facial erythema visual analog scale score was 6 (3) at treatment onset and was 2 (2.5) one month later (P<0.001).

When evaluating facial cutaneous lesions, Demodex infestation should not be overlooked in a patient group like connective tissue diseases with dysfunctional immune system.

Cutaneous leishmaniasis (CL) is an endemic infection in the Middle East, including Iran that is also spreading to new foci. We aimed to determine the leishmaniasis species causing CL in Alborz province.

Overall, out of 55-suspected CL patients referred to health centers in Alborz Province, north central Iran in 2019, 40 patients had positive smear for CL based on optical microscopy. The internal transcribed spacer 1 (ITS1) of nuclear ribosomal DNA (rDNA) was amplified by PCR. Leishmania species were identified by PCR–restriction fragment length polymorphism (PCR-RFLP) using BshF I (Hae III) enzyme.

Out of the 40 positive patients with CL, 34 cases (85%) had been caused by Leishmania (L) major and six (15%) by L. tropica. Fifteen patients had no history of traveling to the disease endemic areas, of which nine were Iranians. Skin lesions and scars caused by CL were mostly observed on the hands and face. Moreover, more than two skin lesions were observed in 22 cases (55%), all of which were infected with L. major. A single skin ulcer was seen in 18 (45%) of the CL patients.

Climate change, reduced rainfall, and demographic changes such as migration into Alborz Province and the increasing marginalization of the population and their entry to settle in new areas might have caused natural transmission of both L. tropica and L. major in this province.

Hydatid cyst mainly involves the liver and lung; however, it can rarely involve cardiac tissue. This study describes the presence of hydatid cysts in the heart with considerable disease points in Tehran, Iran. Two cases aged between 25 to 50 years with cardiac hydatid cyst involvement were identified in 2021 in Tehran, Iran. Epicardial hydatid cyst between a left anterior descending coronary artery (LAD) and left obtuse marginal artery (OM) on the left ventricle, and in the second case, intrapericardial cyst attached to the pulmonary trunk with a thin base were identified. The cardial cysts were resected, and the patients recovered without any complications. Cardiac hydatid cyst is a very rare disease. Rapid diagnosis and surgical and medical care are necessary for treatment.

Crusted scabies (CS) is an extremely contagious variant of classical scabies with substantial morbidity and mortality. It is the most prevalent in immunocompromised patients, those with some underlying diseases, and individuals with physical and mental disabilities. Herein, we report a 70- year-old woman who presented with generalized erythema with itchy hyperkeratotic plaques and crusted lesions on her face, hands, between fingers, neck, scalp, abdomen, and legs up to the knees. She was diagnosed with CS and subsequently isolated and treated with ivermectin (200 μg/kg) and 5% permethrin cream. She died a short time after being admitted, and it was due to severe septic shock and cardiac arrest. Immediate isolation and treatment of CS patients is essential to prevent morbidity and mortality. Prompt diagnosis and precise medical management in both patients and healthcare settings is required.

Echinococcosis is a parasitic disease characterized by cysts in especially liver and lung. We report a long-term survival of a 44-year-old female patient with disseminated echinococcal disease involving the brain, lung, liver, spleen, kidney, mediastinum, thyroid gland, parotid gland, pancreas, peritoneum, rectus muscle, pararenal area, left thigh, skin and breast tissue from Turkey in 2016.

Leeches are rare cause of foreign body in airways. A 23-year-old male, experiencing epistaxis and difficulty in swallowing is presented. During nasopharyngoscopy, a moving leech was observed on the nasopharynx posterior wall in midline location, and removal of the leech was decided under general anaesthesia. The flexible nasopharyngoscopy was inserted, but removal was unsuccessful due to the leech’s movements. Leeches are blood-sucking parasites, so neuromuscular blocking agent was given to prevent the movement. After administration, motion of the leech was lost and easily removed undamaged. In patients presenting with unexplained epistaxis, hemoptysis, dyspnea, and foreign body sensation in the airway, leech infestation should be included as the differential diagnosis and history of contact with stream water should be questioned. We concluded that use of low dose neuromuscular blocking agents facilitates the gentle removal, and could be necessary for successful management of removal of leech under general anaesthesia.