Prevalence of Intestinal Parasites among Rural Inhabitants of Fouman, Guilan Province, Northern Iran with Emphasis on Strongyloides stercoralis.

BACKGROUND: Intestinal parasitic infections (IPIs) are among the most important etiologies of gastrointestinal disorders in developing countries. The present study was performed to determine the prevalence of IPIs in rural inhabitants of Fouman, northern Iran. METHODS: Overall, 31 villages were randomly selected during 2015-2016. Stool samples were collected from 1500 inhabitants aged 2-87. The samples were examined by direct wet smear, formalin ethyl-acetate concentration and agar plate culture. Trichrome staining and modified acid-fast staining were used as confirmatory tests for intestinal amoeba and flagellates and cryptosporidium spp., respectively. Data were analyzed with Chi-Square and Fisher exact tests using SPSS. RESULTS: 8.06% of participants were positive for at least one intestinal parasite. The prevalence of mixed parasitic infections was 0.87%. The most prevalent IPIs were caused by Trichostrongylus spp. (3.13%), followed by Strongyloides stercoralis (1.5%), Giardia lamblia (1.3%), and Entamoeba coli (1.0%), Blastocystis hominis (0.86%), E. histolytica/dispar (0.53%), Endolimax nana (0.26%), Iodamoeba butschlii (0.13%), Trichuris trichiura (0.07%), Enterobius vermicularis (0.07%), Hook worm (0.07%) and E. hartmani (0.07%). Statistically, the prevalence of IPIs showed significant differences regarding the age groups, education status, occupation (P<0.001), and the habit of eating raw vegetables (P<0.007), whereas, the differences were insignificant with regard to sex (P=0.924) and water supply (P=0.088). CONCLUSION: The prevalence of IPIs, especially soil-transmitted helminthes (STHs) has sharply decreased in northern Iran. Excluding Trichostrongylus spp. and S. stercoralis, other intestinal parasites only produce a marginal and unnoticeable health problem in this area, today.

Infection with Hymenolepis diminuta (Rodolphi, 1819) in a Child from North of Iran: Case Report.

We report a human case of Hymenolepis diminuta infection in Guilan Province, northern part of Iran in 2017. The patient was a 15-month-old boy with gastrointestinal symptoms. In stool examination, eggs of H. diminuta was found based on morphological characteristic. The infant was successfully treated with a single oral dose of praziquantel, and then completely recovered. For the first time, we report human infection with this species in north of Iran.

Prevalence and Molecular Aspects of Human Hookworms in Guilan Province, Northern Iran.

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. Following DNA 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.

Molecular identification and phylogenetic analysis of human Trichostrongylus species from an endemic area of Iran.

Human infections with Trichostrongylus species have been reported in most parts of Iran. The aim of this study was the identification, molecular characterization and phylogenetic analysis of human Trichostrongylus species based on ITS2 region of ribosomal DNA from Guilan Province, northern Iran. Stool samples were collected from rural inhabitants and examined by formalin-ether concentration and agar plate culture techniques. After anthelmintic treatment, male adult worms were collected from five infected cases. Genomic DNA was extracted from one male worm of each species in every treated individual and one filariform larva isolated from each case. PCR amplification of ITS2-rDNA region was performed and the products were sequenced. Among 1508 individuals, 46 (3.05%) were found infected with Trichostrongylus species using parasitological methods. Male worms of T. colubriformis, T. vitrinus and T. longispicularis were expelled from five patients after treatment. Out of 41 filariform larvae, 40 were T. colubriformis, and the other one was T. axei. Phylogenetic analysis showed that each species was placed together with reference sequences submitted to GenBank database. Intra-species similarity for all species obtained in the current study was 100%. T. colubriformis was found to be probably the most common species in this region of Iran. For the first time, the authors of the present study report the occurrence of natural human infection by T. longispicularis in the world. Therefore, the number of Trichostrongylus species infecting human in Iran now increased to ten.