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Background: Species of Microsporidia have been known as opportunistic obli-gate intracellular parasites particularly in immunocompromised patients. Enterocyto-zoon bieneusi is one of most prevalent intestinal microsporida parasites in HIV+/AIDS patients. In this study, intestinal microsporidia infection was deter-mined in HIV+/AIDS patients using microscopic and molecular methods. Methods: Stool samples were collected from HIV+/AIDS patients during 12 months. All of the stool specimens washed with PBS (pH: 7.5). Slim slides were prepared from each sample and were examined using light microscope with 1000X magnification. DNA extraction carried out in microscopic positive samples. DNA amplification and genus/species identification also performed by Nested-PCR and sequencing techniques. Results: From 81 stool samples, 25 were infected with microsporidia species and E. bieneusi were identified in all of positive samples. No Encephalitozoon spp. was identified in 81 collected samples using specific primers. Conclusion: E. bieneusi is the most prevalent intestinal microsporidia in immuno-compromised patients of Iran. On the other hand, Nested-PCR using specific pri-mers for ssu rRNA gene is an appropriate molecular method for identification of E. bieneusi.

Background: As a waterborne pathogen, Cryptosporidium is one of the most common causes of gastroenteritis in human and hoofed livestock animals. This study aimed to investigate the distribution of Cryptosporidium spp. in human and livestock wastewaters in Iran, by the 18S rRNA sequence analysis. Methods: A total of 54 raw wastewater samples collected from three urban treatment plants and two slaughterhouses during 2014-2015 in Tehran, Iran. The presence of the Cryptosporidium oocysts was assessed by immunofluorescence with monoclonal antibodies. To characterize the oocysts at the molecular level, the 18S rRNA gene of Cryptosporidium was PCR amplified and sequenced. Results: Of the 54 wastewater samples examined, 34 (62.9%) were positive for Cryptosporidium oocysts using the IFA. Of these, 70.5% (24/34) were positive by PCR, that 91.6% (22/24) were successfully sequenced. The species of C. andersoni (95.4%) and C. xiaoi (4.6%) were detected in livestock wastewater samples. Conclusion: C. andersoni was the major Cryptosporidium sp. found in the aquatic environmental wastewater samples. The high rate of detection of C. andersoni in domestic wastewater was probably the result of the predominancy of this species in cattle herds in Iran. The current study is the first report of C. xiaoi in Iran.

Background: The aim of the study was to determine the helminthic species occurring in great gerbil Rhombomys opimus collected from Maraveh Tappeh, Golestan Province, northeast Iran. Methods: During 2010-2011, a total of 77 R. opimus were captured from rural areas of Maraveh Tap-peh, Golestan Province, using Sherman live traps and examined for infectivity with any larva or adult stages of helminthic parasites. Results: Overall, 63 R. opimus (81.8%) were found infected with different helminthic species. The rate of infectivity with each species was as follows: Trichuris rhombomidis 31.2%, Trichuris muris 32.5%, Trichuris spp. 10.4%, Syphacia muris 2.6%, Dipetalonema viteae (Acanthocheilonema viteae) 37.7%, Skrjabinotaenia lobata 15.6%, Hymenolepis (=Rodentolepis) nana fraterna 5.2%, and Taenia endothoracicus lar-va 1.3%. Conclusion: R. opimus is host for several species of cestodes and nematodes in the study area. The high rate of infectivity with D. viteae indicates the susceptibility of these gerbils to this filarial nema-tode. Synchronous infections occurred up to four species of helminthes in one host.

Background: Hookworm infection is one of the important Neglected Tropical Diseases (NTD) in the world. It was previously more prevalent in the northern and southern parts of Iran with a prevalence rate higher than 40% in some endemic regions; nevertheless, the infection rate has decreased to less than 1%. This study aimed to determine prevalence and molecular aspects of hookworm infections in rural inhabitants of Fouman County, Guilan Province, northern Iran Methods: This cross-sectional study was performed in 31 villages of Fouman district in Guilan Province, northern Iran during 2015-2016. Stool samples were collected from 1500 rural inhabitants and examined by formalin ethyl-acetate concentration as well as agar plate culture techniques. After treatment with albendazole, adult hookworms were isolated. FollowingDNA extraction,PCR amplification of ITS2-rDNA region was performed and the product was sequenced, followed by genetic variation analysis. Results: Of 1500 samples, one case was morphologically diagnosed as N. americanus. In addition, molecular characterization verified the presence of N. americanus, showing more than 95% similarity with sequences of N. americanus present in GenBank. The patient showed no clinical symptoms and a mild hypereosinophilia was the only laboratory finding observed. Conclusion: A reduced prevalence of human hookworms was demonstrated within Guilan Province located in north of Iran. The N. americanus originated from Guilan had a high homology with the isolates found in Japan, Laos, Malaysia, and Australia.

Aim: To investigate the presence of intestinal parasites in tuberculosis patients who suffered from immunodeficiency disorders. Background: Tuberculosis is an important infectious disease that is endemic in some regions of Iran. However, there is a coverage in the endemicity areas of this infection with intestinal parasites. Methods: Stool samples were collected from 50 immunocompromised tuberculosis patients. Direct smear using the normal saline (0.85% NaCl solution) and Lugol’s iodine staining were performed to detect trophozoite of parasites. Moreover, stool samples were concentrated using routine formalin-ether to detect protozoan cysts and helminth’s ova/larvae. Specific staining techniques including Trichrome, Modified Ziehl-Neelsen and chromotrope 2R were employed to detect amoeba, Giardia spp., coccidian parasites and microsporidia. Results: From 50 participants, 42 (84%) and 8 (16%) were male and female, respectively. The mean age + SD of patients was 47.88 + 10.88 years. Among the participated patients, HIV positive, cancer, organ transplant and receiving corticosteroids were seen in 13, 10, 15 and 12 subjects, respectively. The prevalence of Intestinal parasites was 34 %( 17/50). Blastocystis (18%; 9/50), and intestinal helminth (Enterobius vermicularis) (2%; 1/50) were the most prevalent and less prevalent parasites, respectively. Statistical significance difference was not seen between presence of intestinal parasites and type of immunodeficiency. Conclusion: Our findings showed the high prevalence of intestinal parasites with majority of Blastocystis. Indeed, this study suggested that due to complicated immune conditions of TB patients with immunodeficiency disorders, this group of patients are at higher risk of infection by intestinal parasites.

Background: Acanthamoeba genus is introduced as opportunistic and cosmopoli-tan parasite. Monkey and wistar rat are appropriate models for experimental study on Acanthamoeba infection. In this study Acanthamoeba spp. were isolated from hot spring (HS), windows dust (WD) and a corneal sample of keratitis patient (KP) and their pathogenicity surveyed by in vitro and in vivo tests. Methods: Isolates of Acanthamoeba were cultivated axenically for 12 months in PYG medium. Overall, 30 wistar rats, in 6 equal groups were used for developing experimental Acanthamoeba keratitis (AK) and Granulomatous Amoebic Encephalitis (GAE). The Keratitis and Granulomatous Encephalitis experiments were per-formed by intrastromal and intranasal inoculation of Acanthamoeba cysts, respec-tively. Pathogenicity of the three isolates was also evaluated by in vitro test using osmotolerance and temperature tolerance assays. Identification of genotypes were performed by PCR technique and sequencing. Result: None of the isolates could perform AK and GAE in wistar rats, although all isolates were described as T4 genotype. Isolates obtained from KP and WD could grow only in 30 °C, but not in 37 °C and 40 °C. On the other hand, HS iso-late grew in 30 °C and 37 °C but not in 40 °C. Moreover, all of isolate grew in 0.5 M mannitol but not in 1 M and 1.5 M. Conclusion: T4 isolates with a long-term axenic culture and different factors re-lated to host and parasite may play role in pathogenicity of these free-living amoebae.

Background: Blastocystis is one of the most common parasites, reported from both human and animals. This parasite is more prevalent in regions with low levels of hygiene, close contact with animal and unsuitable disposal systems. The aim of the study was to subtype Blastocystis sp., isolated from diarrheic and non-diarrheic patients using sequencing of 18S ribosomal DNA. Methods: Totally, 300 stool samples were collected from diarrheic and non-diarrheic patients referred to Imam Reza Hospital, Tehran from Apr to Aug 2015. All samples were concentrated using conventional Formalin – ether technique and recognized under light microscope. The fresh stool samples were also cultivated in clotted fetal bovine medium and examined for growing of Blastocystis every 48 h with direct smear slides for 10 d.DNA extraction was performed on all positive samples. Amplified DNA fragment of 18S rDNA was sequenced and compared with reference genes, previously deposited in Genbank database. Results: The number of diarrheic and non-diarrheic patients participated in the study was 134 (44.66%) and 166 (55.34%), respectively. Three subtypes 1, 2, 3 were identified from positive samples. Subtype 2 was the most prevalent (36.5%) followed by subtype 1 (33.3%) and subtype 3 (30.2%). There were no mixed subtypes. Furthermore, the most prevalent subtypes in diarrheic and non-diarrheic patients were subtype 2 (39.28%) and subtype 1 (37.14%), respectively. Conclusion: Blastocystis sp., is one of the most prevalent unicellular parasites among diarrheic and non-diarrheic patients. Indeed, ST2 was the most prevalent subtype particularly in those samples collected from diarrheic patients.