Detection of Enterobius vermicularis in archived formalin-fixed paraffin-embedded (FFPE) appendectomy blocks: It's potential to compare genetic variations based on mitochondrial DNA (cox1) gene

Acute appendicitis represents one of the most common causes of emergency abdominal surgery worldwide. Meanwhile, Enterobius vermicularis has been suggested as one of the probable causes of appendicitis. In this study, the morphological characteristics of the remnant pinworms and pathologic changes were explored in old-archived FFPE tissues of appendectomies. Moreover, we provide the first molecular identification, genetic, and haplotype variation of this nematode from the old-archived FFPE tissue section of appendectomy using the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Seventeen FFPE appendectomies with E. vermicularis infection, stored over 12-22 years, were collected from two different geographical areas of Iran. In the histopathological examination, tissue changes were observed in thirteen cases (76.4%) and inflammation in four blocks (23.5%). After DNA extraction, the cox1 gene was amplified in twelve (70.6%) cases using the nested polymerase chain reaction (PCR). Phylogenetic analysis and a median-joining network of 78 available cox1 sequences of E. vermicularis revealed 59 haplotypes. We identified five haplotypes that fell into type B. All Haplotypes are novel except for two haplotypes, Hap32 and Hap37, identical to E. vermicularis sequences from Iran, Greece, and Germany. The ranges of diversity distance and haplotype diversity within the isolates were 0-1.9% and HD:0.643-0.667, subsequently. Overall, the absence of inflammation or even tissue changes in some sections can suggest the possible non-inflammatory role of E. vermicularis in appendicitis. Although FFPE material suffers from PCR inhibition, we could successfully use nested PCR to characterize E. vermicularis in old-archived appendectomy blocks and suggest this method as a complementary diagnosis technique in pathology. While the predominant type was B in the Middle East and Europe, further studies on a larger sample size from different geographical regions could probably confirm the results obtained in the present study.

Molecular and phylogenetic analysis of E. vermicularis in appendectomy specimens from Iran

Human infection with Enterobius vermicularis occurs worldwide, particularly in children. The role of E. vermicularis in appendicitis is neglected. This study was designed to investigate genotypes of E. vermicularis detected from appendectomy specimens in the human population from Iran and clarify the intra-species variation of the parasite. Seventy appendectomies for acute clinical appendicitis isolates from Azerbaijan and North Khorasan of Iran were used in the present study. The genetic information of Tehran and Hamedan regions was also obtained from GenBank for comparison and analysis. The nucleotide sequence of cytochrome c oxidase subunit 1 (cox1) gene was analyzed to perform genetic differentiation, haplotype network analysis, and population structure. Phylogenetic analysis of all the isolates were included in type B haplogroup. The number of haplotypes in all geographical locations of Iran is not much. Network analysis of sequences for regions such as Thailand, Iran, Denmark, and Poland show three classified subtypes B1, B2, and B3 in the B haplogroup. It seems that the haplotypes of E. vermicularis detected from appendectomy are B type, and divided into three subtypes. Further research using another genetic marker is required to elucidate the genetic variation of the parasites in detail.

Enterobius Vermicularis Infection: A Cross-sectional Study in Preschool and School Children in the North-Western Part of Slovenia

Enterobius vermicularis is a prevalent intestinal nematode. The objective of the research was to study enterobiasis prevalence in symptomatic children <15 years of age attending community health center in North - Western part of Slovenia in years 2017 - 2022. Perianal tape tests were performed on three consecutive days. The overall prevalence was 34.2 % (296 out of 864 children included). The mean age of children positive for E. vermicularis was 5.77 (95 % CI: 5.51 - 6.04) and 4.74 (95 % CI: 4.54 - 4.95), p<0.001 for children with negative test results. The positivity rate was not significantly different for boys compared to girls (boys 37.0 %, 95 % CI: 32.4 % - 41.8 %, girls 31.8 %, 95 % CI: 27.6 % - 36.2 %, p=0.107). The number of boys with all three samples positive in a sample set was higher compared to girls (p - value 0.002). Family size affected the positivity rate - the mean number of siblings was higher in positive children. Significant association with E. vermicularis infection was proven by the presence of anal pruritus and absence of abdominal discomfort. High E. vermicularis warrants careful monitoring of trends and public health response. It is necessary to encourage the use of hygiene measures in schools and empower parents to recognize enterobiasis timely.

A Large Adnexal Tumor Caused by Enterobius Vermicularis Mimicking Malignancy

Enterobius vermicularis usually causes trivial infections in the juvenile population. However, its extragenital presentation in adults is relatively rare. We present the case of a 64-year-old female suffering from poorly controlled diabetes and lower abdominal pain. CT scan showed a large tumorous expansion of the lower abdomen, mimicking malignancy. Perioperative findings revealed a large adnexal tumor adhering to the rectum. In addition, the histological examination uncovered a mixed inflammatory infiltrate with multiple surrounding eggs of the parasite and granulomatous reaction in the left fallopian tube and left ovarian cortex. As reported in our article, the rare ectopic sites of Enterobius vermicularis in postmenopause may become a diagnostic challenge.

Enterobius Vermicularis Infections in Iraq

Enterobiasis continues to be among the highest parasitic infections affecting the human population worldwide. A study was conducted between 2011 - 2015 in Iraq to evaluate the enterobiasis reported by the Communicable Diseases Control Center (n=220,607 cases) in relation to demographic (age, sex, rural population and family size) and spatial variables (local and regional sources). Females were more parasitized than males, as well as children and youth ages 4 to 15. Approximately 40 % of cases are from the South region provinces (Thiqar, Miasan, Basrah and Wassit). However, most cases occurred in regions with high rural populations and a high family size average. The results may provide insights for researchers assessing management approaches to control enterobiasis in Iraq.

Prevalence and genetic analysis of Enterobius vermicularis in schoolchildren in lower northern Thailand

Enterobius vermicularis, a nematode parasite with a global distribution causes enterobiasis in schoolchildren and is considered a neglected parasite. An understanding of the prevalence and genetic diversity of enterobiasis is crucial for appropriate control measures. Therefore, the objectives of this research were to study the prevalence and genetic diversity of E. vermicularis in schoolchildren from lower northern Thailand, based on cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) sequences. Using the scotch tape technique, 7.4% (188/2544) of schoolchildren from 21 primary schools were found positive for E. vermicularis eggs, which is a relatively low infection rate. Phylogenetic trees of partial COI sequences (397 bp) revealed similar topologies using maximum likelihood (ML) and neighbor-joining (NJ) methods and identified E. vermicularis type A (105 sequences) and B (1 sequence). Haplotype network analysis of the COI sequences demonstrated a high haplotype diversity (H_d = 0.9028). In contrast, phylogenetic analysts of a 343 bp region of the ITS2 locus (52 sequences) revealed a monophyletic group. More sequence analyses of E. vermicularis from humans and other hosts in Thailand are necessary to better understand the genetic diversity of this parasite.

Current status of helminthiases in Thailand: A cross-sectional, nationwide survey, 2019

Helminthiases are common neglected tropical diseases in Thailand, thus regular surveillance is necessary for their control. During fiscal year 2019, the Thailand Ministry of Public Health carried out a cross-sectional nationwide survey in people of all age groups from the 12 Regional Health Offices in 76 provinces of Thailand. Multi-stage cluster random sampling design was employed to assess the prevalence of helminth infections and certain behavioural risk factors. A total of 16,187 stool samples and demographic data were obtained from the participants. Stool examination was done and parasite eggs/lavae were identified microscopically by experienced technicians. Positive stool samples for Opisthorchis viverrini, hookworms, or Ascaris lumbricoides were further quantified and expressed in eggs per gram feces (EPG). The results revealed an overall prevalence of helminthic infections of 9.79% with over 14 species identified. The highest prevalence was hookworms (4.47%) followed by O. viverrini (2.2%) with mean infection intensities of 222.7 EPG and 120.9, respectively. The majority of the infections were low intensity (97.4% for hookworms and 99.1% for O. viverrini). Similarly for A. lumbricoides, 93.9% of the positive cases were low infections. Two major helminthiases caused by hookworms and O. viverrini were highlighted in this report. While the liver fluke was highly endemic in Northeast Thailand, the hookworms were prevalent in the southmost region of the country. Association with demographic characteristics and risk behaviors of the two parasites were analyzed and presented in this study. Overall, this countrywide survey provides basic information of the current status of helminth infections in Thailand. Moreover, the data clearly indicates a dramatic reduction of O. viverrini prevalence likely due to extensive control activities under the national campaign against the liver fluke over the past five years.

Retrospective analysis and time series forecasting with automated machine learning of ascariasis, enterobiasis and cystic echinococcosis in Romania

The epidemiology of neglected tropical diseases (NTD) is persistently underprioritized, despite NTD being widespread among the poorest populations and in the least developed countries on earth. This situation necessitates thorough and efficient public health intervention. Romania is at the brink of becoming a developed country. However, this South-Eastern European country appears to be a region that is susceptible to an underestimated burden of parasitic diseases despite recent public health reforms. Moreover, there is an evident lack of new epidemiologic data on NTD after Romania's accession to the European Union (EU) in 2007. Using the national ICD-10 dataset for hospitalized patients in Romania, we generated time series datasets for 2008-2018. The objective was to gain deep understanding of the epidemiological distribution of three selected and highly endemic parasitic diseases, namely, ascariasis, enterobiasis and cystic echinococcosis (CE), during this period and forecast their courses for the ensuing two years. Through descriptive and inferential analysis, we observed a decline in case numbers for all three NTD. Several distributional particularities at regional level emerged. Furthermore, we performed predictions using a novel automated time series (AutoTS) machine learning tool and could interestingly show a stable course for these parasitic NTD. Such predictions can help public health officials and medical organizations to implement targeted disease prevention and control. To our knowledge, this is the first study involving a retrospective analysis of ascariasis, enterobiasis and CE on a nationwide scale in Romania. It is also the first to use AutoTS technology for parasitic NTD.

Enterobius vermicularis Infection among Preschool Children: A 12-Year (2008-2019) Survey in Large Cities and Provinces of the Republic of Korea

A 12-year nationwide survey (2008-2019) was performed to investigate the prevalence of Enterobius vermicularis infection among preschool children in Seoul, 4 large cites (Busan, Incheon, Daegu, and Ulsan), and 9 provinces (grouped into 5 localities) in the Republic of Korea (=Korea). The survey was carried out once a year by 16 regional offices of the Korea Association of Health Promotion. The cello-tape perianal swab method (1 smear per child) was applied to detect eggs of E. vermicularis and other helminths. According to the results, the egg positive rate of E. vermicularis infection in 2008-2009 was 1.8-2.0%, but it decreased gradually to 0.6% in 2019 (P<0.05). The prevalence was significantly higher in boys (0.7-5.0%, mean 1.8%) than in girls (0.5-2.8%, mean 1.3%) (P<0.05). The 2 most southern localities, Jejudo (Province) and Jeolla-do (inclusive of Jeollabuk-do and Jeollanam-do) and a mid-western province, Gyeonggi-do, revealed higher prevalences, whereas Seoul and Gangwon-do showed lower prevalences. The results indicate that a low-grade prevalence of E. vermicularis infection (less than 4%) has been maintained for the recent 12 years among preschool children in Korea. Continuous monitoring of enterobiasis in the child age group is necessary in Korea.

Pinworm infection in school children of four districts of Malakand region, Khyber Pakhtunkhwa, Pakistan

Illnesses caused by human pinworm remains a pediatric health problem in developing nations including Pakistan. This study aimed to investigate the prevalence of Enterobius vermicularis in school children of four districts in Malakand region, Pakistan. Four hundred faecal specimens were screened from May 2014 to July 2017 using normal saline and Lugol Iodine solution. Twenty three (5.75%) individuals were found infected with E. vermicularis. Five children (1.25%) were infected with only E. vermicularis and eighteen (4.5%) were mixed with other helminths. E. vermicularis 23 (5.75%), hookworm 11 (2.75%), Ascaris lumbricoides 5 (1.25%), Taenia saginata 2 (0.5%) and Trichuris trichuira 4 (1%) were detected. Age wise 5-8 years were more parasitized followed by 13-15 and 9-12 years of age (0.0296, P<0.05). Male children were highly (0.06700, P<0.05) infected than female. Children in Malakand district were found more infected followed by Dir Upper, similar infection rate was noted in children of districts Lower Dir and Swat (0.0192, P<0.05). Children in primary level were highly (0.0013, P<0.05) infected than those of middle and high levels. Enterobiosis is still the most common parasitic diseases in children. Studies on enterobiosis should be conducted time by time to recognize the hazardous of such parasitic infection in remote areas of the country.

The Diagnosis and Treatment of Pinworm Infection

BACKGROUND

Symptomatic infection with pinworm (Enterobius vermicularis), a human pathogen, is clinically relevant in Germany, with an estimated prevalence in childhood of 2-20%. Enterobiasis can cause major mental distress. There is little systematically verified knowledge on the treatment of this condition, and there is no corresponding German guideline. This review is, therefore, intended as a summary of the current state of knowledge.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed for literature appearing from 1 January 1990 to 5 February 2019 and containing the search terms "enterobiasis," "oxyuriasis," "Enterobius vermicula- ris," "pinworm," and "threadworm."

RESULTS

More than one billion people worldwide are thought to be infected with pinworm. Estimates of its prevalence among kindergarten and primary-school pupils in Europe are generally near 20%. Infants (<2 years of age), adolescents (>14 years of age), and adults are only sporadically affected. The main risk factors are age 4-11 years, uncontrolled anus-finger-mouth contact, nail-biting (onychophagia/peri- onychophagia), unsupervised body hygiene, and poor compliance with basic hand hygiene. No large-scale, randomized, controlled trials of treatment are available. The approved antihelminthic agents are mebendazole, pyrantel embonate, and pyrvinium embonate (success rates up to >90%). For recurrent infections, prolonged treatment for up to 16 weeks (a "pulse scheme") is recommended.

CONCLUSION

In nearly all cases, antihelminthic treatment along with attention to hygienic measures can successfully eradicate pinworm infection and prevent recurrence and autoinfection. The involvement of all persons living in the patient's house- hold, including sexual partners, is a prerequisite to the lasting success of treatment.

Enterobius vermicularis infection: prevalence and risk factors among preschool children in kindergarten in the capital area, Republic of the Marshall Islands

BACKGROUND

Enterobius vermicularis (pinworm) is one of the most common human parasitic helminths, and children are the most susceptible group. Some behavioral and environmental factors may facilitate pinworm infection. In the Republic of the Marshall Islands (RMI), the status of pinworm infections among children remains unknown.

METHODS

In Majuro City, there are 14 kindergartens with a total of 635 preschool children (PSC) whose age range of 5~6 years. The present investigation attempted to determine the pinworm prevalence and associated risk factors as well as investigate whether eggs contaminated the clothes of PSC or the ground and tables in classrooms of 14 kindergartens. Informed consent form and a self-administered questionnaire were given to parents prior to pinworm screening. Perianal specimens were collected by an adhesive scotch tape method, and clothing of belly and hip sites and the ground and tables of the classrooms were inspected using a cellophane tape method to detect any eggs contamination.

RESULTS

In total, 392 PSC (5.28 ± 0.56 yrs. old) participated in this project. The overall prevalence of pinworm infection was 22.4% (88/392). Boys (24.5%) had higher prevalence than girls (20.31%) (p = 0.32). PSC aged > 5 years (32.77%) showed a significantly higher prevalence than those aged ≤5 years (17.95%) (p = 0.01). A univariate analysis indicated that PSC who lived in urban areas (22.95%) had a higher prevalence than those who lived in rural areas (20.69%) (p = 0.69). The employment status of the parents showed no association with the pinworm infection rate (p > 0.05). A logistic regression analysis indicated that "having an older sister" produced a higher risk of acquiring pinworm infection for PSC compared to those who did not have an older sister (OR = 2.02; 95%CI = 1.05~3.88; p = 0.04). No significant association between various other risk factors and pinworm infection was found (p > 0.05). Also, no eggs contamination was found on the clothes of the belly and hip sites or on the ground and tables in the 14 kindergartens.

CONCLUSIONS

Mass screening and treatment of infected PSC are important measures in pinworm control in the RMI.

Genetic variation of Enterobius vermicularis among schoolchildren in Thailand

Enterobiasis, caused by the nematode Enterobius vermicularis, is a common health problem among schoolchildren in Thailand. We provide the first molecular identification of this nematode from Thai schoolchildren and document genetic variation among E. vermicularis eggs using sequence analyses of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and the nuclear ribosomal DNA second internal transcribed spacer (ITS2). A cross-sectional parasitological survey was conducted in schoolchildren (n = 491) in five regions of Thailand between May 2015 and December 2016. The diagnosis of Enterobius infection was made using the adhesive tape perianal swab technique. Enterobius eggs were recovered from 43 participants (8.75%). DNA was extracted from these eggs and the cox1 gene and partial ITS2 region amplified using the polymerase chain reaction (PCR). Nineteen amplified PCR products of the cox1 gene (441 bp) and 18 of the ITS2 region (623 bp) were subsequently sequenced. All sequences were identified as belonging to E. vermicularis based on database searches. Phylogenetic analysis and a median-joining network of available E. vermicularis cox1 sequences showed 66 haplotypes. We found haploclusters (types A and B) represented among the Thai sequences. Six haplotypes from Thailand fell into type A (of Nakano et al., 2006) (along with sequences from Japan and Korea) and five haplotypes into type B (with sequences from Japan, Iran, Czech Republic, Greece, Denmark and Sudan). The overall haplotype diversity (Hd) was 0.9888. Transmission of worms with type B haplotypes from primates to humans in Asia or from humans in Europe possibly occurs in Thailand.

The Incidence of Pinworm (Enterobius Vermicularis) in Pre-school and School Aged Children in the Eastern Slovakia

Helminth infections caused by Enterobius vermicularis have a cosmopolitan character and most often affect the paediatric pre-school and school age population. The presented study was conducted to determine the prevalence of E. vermicularis in the analyzed population of children in the Eastern Slovakia. The Graham’s scotch tape method was used to investigate the presence of Enterobius vermicularis eggs in 390 specimens. The analyzed set consisted of 218 girls and 172 boys, divided by age into three groups – aged from 5 months to 2 years, aged from 3 to 6 years, and aged from 7 to 15 years. Investigation of perianal scotch tapes of children for the presence of E. vermicularis eggs revealed the prevalence of E. vermicularis was P = 3.59 %. Depending on the incidence of E. vermicularis infection, we detected no statistically significant difference (p> 0.05). The prevalence of E. vermicularis in boys was P = 4.07 %, and in girls P = 3.21 %. The highest prevalence of E. vermicularis was recorded in the group of children aged from 3 to 6 years (P = 5.03 %). Most of the samples were positive at age 4 and 5. The lowest prevalence was in the group of children aged from 5 months to 2 years (P = 0.97 %), and the prevalence of E. vermicularis in the group of children aged from 7 to 15 was P = 3.91 %. The difference in the incidence of E. vermicularis infection among different age groups of children was not statistically significant (p> 0.05).

Enterobius vermicularis nematode infection and enterobiasis currently represents a major public health problem in Slovakia. At the present its occurrence is the most frequent in the paediatric population. Therefore it is important to introduce a targeted hygienic-epidemiological measure in children’s collectives, what also should include proper and effective diagnostics and frequent recurrent therapy.