Expression of Matrix Metalloproteinases in Human Cystic Echinococcosis.

BACKGROUND: Cystic echinococcosis (CE) is a zoonotic disease caused by the Echinococcus granulosus senso lato (E. granulosus s.l.) larval stages. Parasitederived products have been shown to regulate host matrix metalloproteinases (MMPs), contributing to CE pathogenesis and progressive liver fibrosis in intermediate hosts. The current study aimed to investigate the potential role of MMP1, 7, 8, and 13 in E. granulosus s.l-induced liver fibrosis. METHODS: Thirty CE patients with active, transitional, or inactive hydatid cysts were enrolled in this study to determine the inductive effects of E. granulosus on the expression of MMP-1, MMP-7, MMP-8, and MMP-13 in healthy liver tissue and fibrotic liver tissue using qRT-PCR. RESULTS: According to the WHO-IWGE classification, patients with functional cysts (CE1 and CE2) had the highest percentage (46.6%). MMP-1, MMP-7, MMP-8, and MMP-13 expression levels were significantly higher in fibrotic liver than in normal liver tissue. MMP-13 and MMP-1 had the highest and lowest expression levels among MMPs. Compared to the normal group, the fold change for MMP-13 in the fibrotic group was greater than 12 and had the highest AUC value (AUC= 0.8283). CONCLUSION: Our findings suggest that E. granulosus-derived products might be involved in regulating host MMPs. Thus, MMPs may be considered potential biomarkers for predicting CE prognosis. Because of the non-normal distribution of our patients' CE types, further research, particularly on circulation MMPs, is needed to confirm the potential role of MMPs in CE pathogenesis and to follow up on CE patients.

Can Echinococcus granulosus-Derived MicroRNAs be Biomarkers for Diagnosis and Follow-up of Cystic Echinococcosis Patients?

INTRODUCTION: Cystic echinococcosis (CE) is a neglected tropical disease caused by the larval stages of Echinococcus granulosus (E. granulosus). MicroRNAs (miRNAs) are small noncoding RNAs acting as mediators in host-parasite interaction. Recently, numerous studies have been conducted on miRNAs in infectious diseases; however, little data are available about the role of miRNAs in pathogenesis and early diagnosis of CE. METHODS: The current study evaluated the expression of four E. granulosus-derived miRNAs, including egr-miR-125,5p, egr-let-7,5p, egr-miR-2, and egr-miR-71 in fibrotic and healthy liver tissues of 31 CE patients with active and inactive hydatid cysts by qRT-PCR. RESULTS: Of the 31 patients, 48.4% had active cysts (CE1 and CE2), while the remainder had transitional (16.1%) and inactive (35.5%) CE types cysts. The qRT-PCR analysis revealed a significant increase of 11.2, 9.91, 6.2, and 13.1-fold in the fibrotic tissue group for egr-miR-125,5p, egr-let-7,5p, egr-miR-2, and egr-miR-71, respectively. Among these miRNAs, egr-miR-125-5p exhibited the highest area under the curve (AUC) value of 0.8050 for predicting liver fibrosis. CONCLUSIONS: Our findings provide new data about the role of E. granulosus-derived miRNAs in pathogenesis of CE. The high AUC of egr-miR125,5p reflecting the possibility of using egr-miR125,5p as biomarker in CE diagnosis. Further studies on serum of CE patients are needed to confirm the potential role of circulating egr-miR-2a-3p and egr-miR-125-5p in the early diagnosis of CE.

Serum Level of egr-miR-2a-3p as a Potential Diagnostic Biomarker for Cystic Echinococcosis.

INTRODUCTION: Cystic Echinococcosis (CE) is a chronic parasitic disease caused by the metacestodes of Echinococcus granulosus senso lato (E. granulosus s.l.). The larval stages of this parasite, hydatid cyst, are usually diagnosed using imaging modalities and serological testing; however, several studies have recently suggested using the parasite-derived microRNAs (miRNAs) as novel diagnostic biomarkers. MATERIALS AND METHODS: The present study included 31 CE patients who were older than 5 years and were admitted to the hospitals of Ahvaz, Iran for hydatid cyst removal surgery during 2019-2021. The egr-miR-125-5p and egr-miR-2a-3p levels were evaluated in the sera of the CE patients before and 6 months after the surgery using Quantitative Real-Time PCR (qRT-PCR), and the results were compared with the serum samples from 15 healthy volunteers. Then, the intergroup comparisons were performed using the t test. RESULTS: The patients' age range was 6-72 years, with a mean age of 34.6 years. Moreover, based on the classification by the WHO-IWGE, one patient (3.2%) had CE1, 14 patients (45.2%) had CE2, 5 patients (16.1%) had CE3, 2 patients (6.5%) had CE4, and 9 patients (29%) had CE5. Also, 21 patients (67.74%) had a positive antigen test using the ELISA method, while 10 patients (32.26%) had a negative ELISA. The pre-operative expression level of egr-miR-2a-3p was 10.36 folds higher compared to 6 months after the surgery, with an AUC value of 0.8176. However, the expression levels of egr-miR-125-5p did not change significantly 6 months after the surgery compared to pre-operative levels. CONCLUSIONS: According to the present study results, the serum levels of egr-miR-2a-3p can be a promising non-invasive biomarker for diagnosing CE and monitoring its potential recurrence after cystectomy.

The Role of Tissue Inhibitor of Metalloproteinase-1 and 2 in Echinococcus granulosus senso lato-Induced Human Hepatic Fibrosis.

INTRODUCTION: The main mechanism underlying hepatic fibrosis is the imbalance between tissue Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Metalloproteinases (TIMPs). This study aimed to investigate the potential role of TIMP-1 and TIMP-2 in the process of hepatic fibrosis caused by Echinococcus granulosus senso lato (E. granulosus s.l.). METHODS: The expressions levels of TIMP-1 and TIMP-2 mRNAs were evaluated in fibrotic and normal hepatic tissues of 30 patients with Cystic Echinococcus (CE) using qRT-PCR. Moreover, their serum levels of TIMP-1 were assessed before CE cyst removal and 6 months after surgery using ELISA. RESULTS: The qRT-PCR results showed that the expression levels of TIMP-1 and TIMP-2 mRNAs were significantly higher in the fibrotic hepatic tissue compared to the normal liver tissue, in a way that the TIMP-1 and TIMP-2 mRNA expression levels were 19.07 and 6.58 folds higher in the fibrotic tissue compared to the normal liver tissue. Among these TIMPs, TIMP-1 exhibited the higher area under the curve (AUC) value for predicting liver fibrosis. However, we could not find a significant difference in the serum levels of TIMP-1 before and after the cyst removal procedure (p = 0.48). CONCLUSIONS: For the first time, our study showed that the significant overexpression of both TIMP mRNAs in the fibrotic liver tissue of the CE patients may be due to the increased expression of MMPs in the peri-cystic tissue. However, we could not find a significant difference in the pre- and post-operative TIMP-1 levels, which may be due to recurrence or heterogeneity in the cyst type. Therefore, performing further studies with a larger sample size of the CE patients is recommended.

Primary disseminated intraabdominal hydatidosis: a case report.

BACKGROUND: Hydatidosis, a zoonotic disease caused by the larvae of Echinococcus granulosus sensu lato (E. granulosus s.l.), can be primary or secondary. However, primary disseminated intraabdominal hydatidosis is a rare form of the disease, accounting for about 2% of all intraabdominal cysts. CASE PRESENTATION: We report herein a case of primary disseminated intraabdominal hydatidosis with multiple organ involvement in a 51-year-old Iranian man presenting to a healthcare facility with abdominal pain. During the physical examination, two abdominal masses were palpated. Ultrasound and computed tomography revealed six cystic lesions in the patient's liver, subhepatic region, pelvic, and omentum. Afterward, he underwent surgery, during which the cystic lesions were completely removed. The patient received albendazole (400 mg/kg/day) postoperatively and was recommended to continue the treatment for 4 months. CONCLUSIONS: Although primary disseminated intraabdominal hydatidosis is rare, this problem is of great importance due to the fertility of cysts and the high risk of recurrence. Therefore, it is recommended to follow such patients with imaging modalities and enzyme-linked immunosorbent assay for native antigen B (AgB). In addition, patients should undergo albendazole therapy postoperatively for 4 months.

Twenty-six years of involvement with cystic echinococcosis: a case report.

INTRODUCTION: Spinal hydatidosis, a zoonotic disease caused by infection with Echinococcus spp. larvae, is rare, but its treatment remains a significant medical challenge. Approximately 70% of patients with spinal hydatidosis have lesions in their liver, 0-15% have lung involvement, and only 0.5-2% have bone involvement. CASE PRESENTATION: Here we report a 38-year-old Iranian man with spinal hydatidosis, who had a history of eight times surgery in over of 26 years due to hydatid cyst in the liver, lungs, and chest wall. At the most recent admission to hospital he presented with chest pain, paraplegia, and urinary incontinence. Magnetic resonance imaging revealed thoracic spinal hydatid disease. He underwent surgery, and the hydatid cysts were completely removed. Lower extremity forces recovered dramatically and completely within 4 weeks. CONCLUSION: Spinal hydatidosis is a rare disease, but it is associated with a high degree of morbidity, mortality, and poor prognosis. Because of the infiltrative nature of hydatid disease, surgery alone is rarely curative. The current case study demonstrates the importance of a suitable surgical approach, adequate intraoperative prophylaxis to prevent cyst rupture, and prolonged complete paraplegia.

Screening of Strongyloides stercoralis infection in high-risk patients in Khuzestan Province, Southwestern Iran.

BACKGROUND: Strongyloidiasis, one of the neglected tropical diseases (NTDs), can be fatal in immunocompromised patients. Available data on Strongyloides stercoralis infection in high-risk patients in Iran are limited. The aim of the present study was to determine the prevalence of S. stercoralis infection and associated risk factors among high-risk patients as well as to evaluate the sensitivity of the diagnostic tests used in the diagnose of S. stercoralis infection. METHODS: This cross-sectional study was performed from 2019 to 2020 among 300 high-risk patients in Khuzestan Province, southwestern Iran. Patients with autoimmune diseases, uncontrolled diabetes, HIV/AIDS, cancer, organ transplant, hematological malignancy, asthma and chronic obstructive pulmonary disease (COPD) were examined using direct smear examination, formalin-ether concentration, Baermann funnel technique, agar plate culture, and ELISA test. Since agar plate culture was considered the reference diagnostic test, culture-positive samples were confirmed by PCR amplification and the sequencing of the nuclear 18S rDNA (SSU) hypervariable region (HVRIV) of the parasite. RESULTS: The prevalence of S. stercoralis infection was 1%, 1.3%, 2%, 2.7%, and 8.7% using direct smear examination, formalin-ether concentration, Baermann funnel technique, agar plate culture, and ELISA test, respectively. All culture-positive samples were confirmed by SSU-PCR. According to the results, the most sensitive test was ELISA, with 100% sensitivity, followed by the Baermann funnel technique with the sensitivity of 75%. Direct smear examination, formalin-ether concentration technique, and Baermann funnel technique had the highest PPV (100%) while the ELISA test had the highest NPV (100%). Significant eosinophilia was observed in the patients whose culture test was positive (7/8; P < 0.05). In the present study, the majority of the positive cases by the agar plate culture had a history of prolonged exposure to soil and of asthma and COPD and were > 60 years old. CONCLUSIONS: Given that the ELISA test had the highest NPV, the screening of all high-risk patients for S. stercoralis infection in endemic areas is recommended prior to starting corticosteroid therapy with the ELISA test. The results indicate the importance of paying attention to patients with unknown eosinophilia in endemic areas. Ivermectin should be available to strongyloidiasis patients in the endemic areas.

Gene expression in human liver fibrosis associated with Echinococcus granulosus sensu lato.

Liver fibrosis is a dynamic process that occurs in response to chronic liver disease resulting from factors such as chronic infections, autoimmune reactions, allergic responses, toxins, radiation, and infectious agents. Among the infectious agents, multicellular parasites cause chronic inflammation and fibrosis. Twenty-five patients with different stages of cystic echinococcosis (CE) were enrolled in the study. The expression of ACTA2, COL3A1, IFN-γ, MMP2, MMP9, TGF-ß1, and TNF-α genes was determined by qRT-PCR in healthy and fibrotic liver tissue of the CE patients. TGF-ß1 expression was evaluated by immunohistochemistry, and histology was conducted to assess the development of liver fibrosis. Expression of MMP9, ACTA2, COL3A1, and MMP2 was found significantly higher in the fibrotic tissue compared to healthy tissue. We observed a significant correlation between TGF-ß1 and TNF-α gene expressions and liver fibrosis. The mRNA level of IFN-γ was lower in the fibrotic than in the healthy hepatic tissue. Immunohistochemistry analysis revealed TGF-ß1 upregulation in the fibrotic tissue. Histology showed inflammation and fibrosis to be significantly higher in the fibrotic tissue. The findings of this study suggest that Echinococcus granulosussensu lato can promotes fibrosis through the overexpression of TGF-ß1, MMP9, ACTA2, COL3A1, and MMP2. The downregulation of IFN-γ mRNA in fibrotic samples is probably due to the increased production of TGF-ß1 and the suppression of potential anti-fibrotic role of IFN-γ during advanced liver injury caused by E. granulosussensu lato.

Cytokine profiles in peripheral blood mononuclear cells from patients with cystic echinococcosis.

INTRODUCTION: Cystic echinococcosis (CE) is a chronic zoonotic disease caused by the larval stage of Echinococcus granulosus (E. granulosus), which affects domestic and wild carnivores as the definitive host and ungulates as intermediate hosts. In intermediate hosts, both Th1 and Th2 cells are involved in the immune responses to an echinoccocal infection. This study aimed to investigate production of IL-4, IL-10, and IFN-γ cytokines in peripheral blood mononuclear cells (PBMCs) of CE patients before and after surgical treatment. METHODS: To evaluate cytokine production in response to E. granulosus antigens, we investigated IL-4, IL-10, and IFN-γ production in PBMCs of 20 CE patients in response to hydatid cyst fluid antigen (HCF-Ag) before and after surgical treatment using ELISA. RESULTS: The mean IL-4 production from HCF-Ag stimulated PBMCs was significantly decreased (p < 0.05), while IFN-γ was significantly increased in HCF-Ag stimulated PBMCs in patients after surgery (p = 0.005). Furthermore, our results showed that there is no significant difference between IL-10 production in patients before and after treatment (p = 0.562). CONCLUSIONS: Our data Indicated production of IL-4 in cultured PBMCs of CE patients stimulated with HCF-Ag was decreased significantly. While, production of IFN-γ was increased significantly in responses to HCF Ag after surgery. We concluded that the evaluation of IL-4 and IFN-γ in HCF-Ag stimulated PBMCs of CE patients should be considered as a useful marker in the follow up of patients with cystic echinococcosis.

Multilocus genotyping of Giardia duodenalis in Southwestern Iran. A community survey.

Giardia duodenalis is one of the main enteric pathogens associated with diarrheal disease. In developing countries, giardiasis is a major public health concern, particularly in children under five years of age. This study aimed to evaluate the occurrence and genetic diversity of G. duodenalis causing human infections in Shushtar County, Southwestern Iran. Individual faecal specimens were collected from 1,163 individuals (male/female ratio: 0.9; age range 2-75 years) with (n = 258) and without (n = 905) gastrointestinal symptoms living in rural and urban settings during the period 2017-2018. Conventional (sucrose flotation and microscopy) methods were used for the initial detection of G. duodenalis cysts in faecal specimens. Microscopy-positive samples were confirmed by PCR amplification and sequencing of the small subunit rRNA (ssu rRNA) gene of the parasite. A multilocus genotyping (MLG) scheme targeting the triose phosphate isomerase (tpi), the glutamate dehydrogenase (gdh), and the beta-giardin (bg) genes was used for genotyping purposes. Giardia duodenalis cysts were detected in 7.7% (90/1,163) of samples by microscopy, of which 82 were confirmed by ssu-PCR. Successful amplification and sequencing results were obtained for 23.2% (19/82), 9.8% (8/82), and 8.5% (7/82) of the confirmed samples at the tpi, gdh, and bg loci, respectively. MLG data for the three loci were available for two samples only. Out of the 24 samples genotyped at any loci, 50% (12/24) were identified as assemblage A and the remaining half as assemblage B. Overall, AII was the most prevalent sub-assemblage detected (41.7%, 10/24), followed by BIII (25.0%, 6/24), discordant BIII/BIV (5/24) or AII/AIII (2/24) sequences, and BIV (1/24). No significant correlation was demonstrated between a given assemblage/sub-assemblage and the occurrence of clinical symptoms. No genotypes adapted to animal hosts other than humans (e.g. assemblages C-F) were found circulating in the investigated human population, suggesting that transmission of human giardiasis in this Iranian region is primarily of anthroponotic nature. Further molecular-based studies are needed to confirm and expand these results, and to ascertain the presence and public health relevance of the parasite in environmental (e.g. drinking water) samples.

The Seroprevalence of Cystic Echinococcosis in a Rural Normal Population, Southwestern Iran.

INTRODUCTION: Cystic echinococcosis is a neglected zoonotic disease with worldwide distribution, which occurs mainly in pastoral regions. Echinococcus granulosus sensu stricto, is the main agent of human infection. Although Iran is an endemic area for CE in the Middle East, lack of data regarding the disease among rural inhabitants of Khuzestan province in recent years, persuaded us to perform the current study. METHODOLOGY: This cross-sectional study was conducted in 2016 using simple random sampling method in 15 villages of Shushtar County, southwestern Iran. Three hundred and fourteen rural inhabitants were examined using AgB- ELISA test for CE. RESULT: From 314 patients included in the study, females and males were 244 (77.7%) and 70 (22.3%), respectively. Of these, 227 (72.3%) were in close contact with dogs, out of which 173 (70.9%) of them were females and 54 (29.1%) were males. ELISA detected three (1%) seropositive cases among investigated population. All three positive cases were females and in close contact with dogs. Furthermore, the positive cases were in the age range of 21-50. None of the 70 examined males were positive. CONCLUSION: This study is the first report of CE in rural areas of Shushtar, Southwest Iran, which indicated seroprevalence of CE among rural areas with a high prevalence rate of infection among females. It seems that the rural population of the region are at the risk of exposure to E. granulosus eggs. Therefore, more studies are required to evaluate the human CE in all parts of the province using serological and ultrasound methods.

Screening municipal waste collectors for cystic echinococcosis and toxocariasis in southwestern Iran.

INTRODUCTION: Cystic Echinococcosis (CE) and toxocariasis caused by the larval stages of intestinal dog worms including Echinococcus granulosus and Toxocara spp. are among the most widespread zoonotic diseases. METHODOLOGY: Four hundred municipal waste collectors were serologically evaluated for CE and toxocariasis. To identify the seropositive cases of CE, an ELISA test was performed using native AgB. Toxocara IgG detection was carried out using ELISA DRG kit (USA), and the seropositive cases were then examined by a Western blot kit (LDBIO, France) to confirm the positive ELISA results. RESULTS: 15 (3.7%) workers were seropositive for CE according to the ELISA. A significant relationship was observed between being seropositive and having contact with soil and dogs. No significant correlations were observed between education and the prevalence of these diseases. Of the 15 seropositive workers for CE, ten worked in district 5 of Ahvaz. Toxocara IgG was identified in 11 (2.7%) cases using the ELISA; however, none of them were confirmed by Western blotting. CONCLUSION: The 3.7% rate of seroprevalence for CE in asymptomatic municipal waste collectors living in urban regions of Ahvaz suggests a high rate. The higher rate of infection among workers in district 5 is likely associated with the presence of stray and owned dogs in that area of the city. A prolonged exposure to contaminated soil, the lack of awareness about the risk of diseases that can be transmitted through waste and the lack of general availability of suitable personal protective equipment for waste collectors might cause infectious diseases.

Multiple zoonotic helminth infections in domestic dogs in a rural area of Khuzestan Province in Iran.

BACKGROUND: Echinococcosis and toxocarosis caused by the genus of Echinococcus and Toxocara spp. are among important helminthic diseases worldwide. Limited data on the prevalence of these parasites persuaded us to determine the prevalence of E. granulosus, E. multilocularis, and T. canis infections in domestic dogs in rural areas of Ahvaz, southwestern Iran. Fecal samples from 167 domestic dogs were examined using both microscopy and PCR techniques. Multiplex PCR was performed for the presence of Echinococcus, and Taenia spp. and single PCR for detection of T. canis and Toxascaris leonina. RESULTS: The total occurrence of identified parasites was 65 (38.9%). The microscopic examinations showed that 40 (24%), 18 (10.8%), and four (2.4%) of dogs were infected with taeniid-like, ascarid, and both genera eggs, respectively. Echinococcus granulosus was identified in seven (4.2%), Taenia spp. in 29 (17.4%), and mixed infection with both in 11 (6.6%) samples. Sequencing of PCR-positive samples identified E. granulosus s.s. (G1), 18 T. hydatigena (10.8%), five T. multiceps (3%), three T. serialis (1.8%), one T. ovis (0.6%), one Spirometra erinaceieuropaei voucher (0.6%), and two Mesocestoides corti (1.2%). This is the first report of S. erinaceieuropaei voucher and M. corti in dogs in Iran. Nine (5.4%) and 16 (9.6%) dogs showed infection with T. canis and T. leonina, respectively. Two samples showed coinfection with both ascarids. CONCLUSIONS: Several studies have reported echinococcosis and toxocarosis in intermediate hosts from the southwest of Iran; however, this study is the first molecular research on E. granulosus and T. canis in domestic dogs in a rural area of southwestern Iran. Furthermore, issues of soil contamination with dogs' feces and recent dust storms in Khuzestan may have a role in the spreading of these zoonotic infections to other provinces close to it, and neighboring countries such as Iraq.

Molecular identification of Echinococcus multilocularis infection in small mammals from Northeast, Iran.

BACKGROUND: Alveolar echinococcosis is a zoonotic disease caused by the metacestode of Echinococcus multilocularis. Many species of small mammals, including arvicolid rodents or Ochotona spp., are natural intermediate hosts of the cestode. The main aim of this study was to identify natural intermediate hosts of E. multilocularis in Chenaran County, Razavi Khorasan Province, northeastern Iran, where the prevalence of infected wild and domestic carnivores is high. METHODOLOGY/PRINCIPAL FINDINGS: A program of trapping was carried out in five villages in which this cestode was reported in carnivores. The livers of 85 small mammals were investigated for the presence of E. multilocularis infection using multiplex PCR of mitochondrial genes. Infections were identified in 30 specimens: 23 Microtus transcaspicus, three Ochotona rufescens, two Mus musculus, one Crocidura gmelini, and one Apodemus witherbyi. CONCLUSIONS/SIGNIFICANCE: A range of small mammals therefore act as natural intermediate hosts for the transmission of E. multilocularis in Chenaran County, and the prevalence suggested that E. multilocularis infection is endemic in this region. The existence of the life cycle of this potentially lethal cestode in the vicinity of human habitats provides a significant risk of human infection.

Prevalence of zoonotic intestinal parasites in domestic and stray dogs in a rural area of Iran.

Certain zoonotic parasites are enteropathogens in dogs that cause serious human disease such as cystic echinococcosis, human alveolar echinococcosis, visceral larva migrans, and ocular larva migrans. This study investigated the prevalence of intestinal parasites in dogs in the Chenaran County, Razavi Khorasan Province, Iran. Sampling was carried out randomly in 17 villages from November 2009 to January 2010. Seventy-seven fecal samples from 28 domestic and 49 stray dogs were examined using sieving/flotation and modified Ziehl-Neelsen staining. Intestinal parasites were found in 51 of the 77 (66%) dogs most common being Toxascaris leonina (29%, 22/77), Toxocara spp. (25%, 19/77), Eimeria spp. (19%, 15/77), Taenia/Echinococcus spp. (18%, 14/77), Sarcocystis spp. (17%, 13/77), and Dicrocoelium dendriticum (14%, 11/77). Lower infection rates of parasites were observed for Trichuris vulpis (6%, 5/77), Cryptosporidium spp. (5%, 4/77), and Physaloptera spp. (3%, 2/77). Prevalence of infection by Dipylidium caninum, Capillaria spp., Cystoisospora spp., and hookworms was similar (1%, 1/77). This study is the first report of the prevalence of intestinal parasites of domestic and stray dogs in Chenaran County, Northeast Iran. The higher prevalence of zoonotic intestinal parasites such as Toxascaris leonina, Toxocara spp. and Taenia/Echinococcus spp. compared to other parasites indicates the need for control programs to minimize the risk of transmission of zoonotic disease, particularly cystic echinococcosis, alveolar echinococcosis, visceral larva migrans, and ocular larva migrans to people living in these areas.

Detection of Echinococcus multilocularis in carnivores in Razavi Khorasan province, Iran using mitochondrial DNA.

BACKGROUND: Echinococcus multilocularis is the source of alveolar echinococcosis, a potentially fatal zoonotic disease. This investigation assessed the presence of E. multilocularis infection in definitive hosts in the Chenaran region of Razavi Khorasan Province, northeastern Iran. METHODOLOGY/PRINCIPAL FINDINGS: Fecal samples from 77 domestic and stray dogs and 14 wild carnivores were examined using the flotation/sieving method followed by multiplex PCR of mitochondrial genes. The intestinal scraping technique (IST) and the sedimentation and counting technique (SCT) revealed adult Echinococcus in the intestines of five of 10 jackals and of the single wolf examined. Three jackals were infected only with E. multilocularis but two, and the wolf, were infected with both E. multilocularis and E. granulosus. Multiplex PCR revealed E. multilocularis, E. granulosus, and Taenia spp. in 19, 24, and 28 fecal samples, respectively. Echinococcus multilocularis infection was detected in the feces of all wild carnivores sampled including nine jackals, three foxes, one wolf, one hyena, and five dogs (6.5%). Echinococcus granulosus was found in the fecal samples of 16.9% of dogs, 66.7% of jackals, and all of the foxes, the wolf, and the hyena. The feces of 16 (21.8%) dogs, 7 of 9 (77.8%) jackals, and all three foxes, one wolf and one hyena were infected with Taenia spp. CONCLUSIONS/SIGNIFICANCE: The prevalence of E. multilocularis in wild carnivores of rural areas of the Chenaran region is high, indicating that the life cycle is being maintained in northeastern Iran with the red fox, jackal, wolf, hyena, and dog as definitive hosts.