Enterobius vermicularis as a Novel Surrogate for the Presence of Helminth Ova in Tertiary Wastewater Treatment Plants

Significant effort has gone into assessing the fate and removal of viruses, bacteria, and protozoan parasites during wastewater treatment to provide data addressing potential health risks associated with reuse options. Comparatively less is known about the fate of parasitic worm species ova in these complex systems. It is largely assumed that these helminths settle, are removed with the sludge, and consequently represent a relatively low risk for wastewater reuse applications. However, helminths are a highly diverse group of organisms that display a wide range of physical properties that complicate the application of a single treatment for helminth reduction during wastewater treatment. Moreover, their diverse biological and physical properties make some ova highly resistant to both disinfection (i.e., with chlorine or UV treatment) and physical removal (settling) through the wastewater treatment train, indicating that there may be reason to broaden the scope of our investigations into whether parasitic worm eggs can be identified in treated wastewater. The ubiquitous human parasitic nematode Enterobius vermicularis (pinworm) produces small, buoyant ova. Utilizing a novel diagnostic quantitative PCR (qPCR), this study monitored E. vermicularis presence at two full-scale wastewater treatment plants over the course of 8 months and demonstrated incomplete physical removal of E. vermicularis ova through tertiary treatment, with removal efficiencies approximating only 0.5 and 1.6 log10 at the two wastewater treatment plants based on qPCR. These findings demonstrate the need for more-diverse surrogates of helminthic ova to fully assess treatment performance with respect to reclaimed wastewaters.IMPORTANCE Helminths, despite being a diverse and environmentally resistant class of pathogens, are often underestimated and ignored when treatment performance at modern wastewater treatment plants is considered. A one-size-fits-all surrogate for removal of helminth ova may be inappropriate to adequately assess risk and ensure public safety when treated and partially treated wastewaters are encountered. This study argues for the use of human pinworm as a conservative indicator of the presence of helminth ova due to its small size, buoyancy, prevalence in humans, and environmental resistance.

Is the treatment of Enterobius vermicularis co-infection necessary to eradicate Dientamoeba fragilis infection?

OBJECTIVES

Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a worldwide distribution, which has emerged as an important and misdiagnosed cause of chronic gastrointestinal illnesses such as diarrhea and 'irritable-bowel-like' gastrointestinal disease. Very little research has been conducted on the use of suitable antimicrobial compounds. Furthermore, higher rates of co-infection with Enterobius vermicularis have been described, suggesting that E. vermicularis could influence the treatment of D. fragilis-infected patients. To study this, the treatment of E. vermicularis and D. fragilis co-infected patients was evaluated.

METHODS

Forty-nine patients with a D. fragilis infection, including 25 (51.0%) patients co-infected with E. vermicularis, were studied. All of them were treated with metronidazole. Patients with E. vermicularis co-infection and/or an E. vermicularis-positive case in the family were treated with mebendazole.

RESULTS

Metronidazole treatment failure was significantly more frequent in patients with E. vermicularis co-infection and in patients with children in the family.

CONCLUSIONS

Co-infection with E. vermicularis may act as a factor favoring D. fragilis infection by preventing eradication measures. This suggests that both parasites should be treated simultaneously.

[Enterobiasis in pediatric subjects in north-western Italy: a study of home remedies]

The present study examines the most common home remedies in the Piedmont region of northwest Italy currently used in the treatment of pediatric enterobiasis, commonly known as pinworm infection. The remedies in question, typically based on popular beliefs and as such are nearly useless, were noted through interviews with subjects who had come to the local Hygiene and Public Health Services offices for information about pinworm prevention and treatment. Analysis of replies by the subjects clearly indicates that local families are ill-prepared to recognize the symptoms this parasitic infection; often it is confused with pediatric ketosis, therefore leading to inappropriate treatment which at times may be potentially harmful to the patient.

Chronic diarrhea and abdominal pain: pin the pinworm

Enterobius vermicularis is the most common helminthic infection in the US. It is usually considered an innocuous parasite that at the most causes perianal itching. We report a case of an 84-year-old female patient from an assisted living facility who presented with symptoms of colitis for 2 months. On detailed history and exam, she was found to have E. vermicularis infection. All her symptoms resolved dramatically within 2 days after a single dose of albendazole. We want to emphasize the importance of including parasitic infections such as E. vermicularis in the differential diagnoses of patients presenting with symptoms of colitis.

Enterobiasis: a neglected infection in adults

In this study, adult patients were treated with praziquantel to expel intestinal flukes. Unexpectedly, dozens of adult Enterobius vermicularis worms with disfigured morphology, which had not been detected on fecal examination using Kat's modified thick-smear technique, were expelled from 6 of 33 patients.

Fenbendazole treatment and litter size in rats

Fenbendazole is commonly used in laboratory animal medicine as an anthelmintic for elimination of pinworms. It is generally regarded as a safe drug with minimal side effects. In our facility, 2 breeding colonies of rats were treated with fenbendazole to eliminate pinworms. Analysis of the breeding records revealed that feeding Sprague-Dawley rats a diet containing fenbendazole on a continuous basis for 7 consecutive weeks was associated with a significant reduction in litter size. Although the mechanism underlying this effect is unknown, the finding prompts caution when using fenbendazole to treat valuable breeding colonies or strains that are poor breeders.

[Effect of a novel drug--enteric coated tribendimidine in the treatment of intestinal nematode infections]

OBJECTIVE

To study the therapeutic effect and possible adverse effects of tribendimidine enteric coated tablets in the treatment of infections due to hookworms, Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis.

METHODS

According to the standard clinical trial design and protocol, persons infected with hookworms, Ascaris lumbricoides, Trichuris trichiura, or Enterobius vermicularis respectively, were treated with tribendimidine enteric coated tablets in four counties of Guangdong and Jiangsu Provinces, albendazole was used as control.

RESULTS

For hookworm infection, the curative rate (eggs negative in the faeces) were 89.5% (85/95) and 70.6% (60/85) with tribendimidine (400 mg) and albendazole(400 mg) respectively; for Ascaris infection, 97.4% (114/117) and 98.9% (91/92) with tribendimidine(300 mg) and albendazole(400 mg) respectively; for Trichuris infection, 33.3% (25/75) and 56.1% (23/41) with tribendimidine(400 mg/day for 3 days) and albendazole(400 mg/day for 3 days) respectively; for Enterobius infection in children, 74.1% (60/81) and 93.0% (40/43) with tribendimidine(200 mg) and albendazole(200 mg) respectively. No considerable side effect was found.

CONCLUSION

Tribendimidine is highly active in the treatment of hookworm, Ascaris lumbricoides infections, free of major adverse effect and easy to administer. It is more effective than albendazole for the infection of Necator americanus.

EFFECTS OF REPEATED ANTHELMINTIC TREATMENT ON ENTEROBIUS VERMICULARIS INFECTION IN CHIMPANZEES

Effects of repeated treatment with pyrantel pamoate on Enterobius vermicularis infection in chimpanzees were assessed by observing worms discharged in the feces after administration of anthelmintic treatment. Three of 9 chimpanzees reared in a zoological garden in Japan were subjected to fecal worm count and morphometric observation, and all were given oral pyrantel pamoate 6 times at 10-day intervals simultaneously. Following the first and second treatments, more than 30,000 pinworms were discharged from 1 chimpanzee. The number of discharged worms abruptly decreased after the third treatment, and only a few worms were recovered after the fifth treatment, indicating that repeated treatment at short intervals was very effective. Complete eradication was not achieved, however, presumably because of reinfection. The female proportion among discharged worms tended to increase as the treatment was repeated.

Assessment of frequency, transmission, and genitourinary complications of enterobiasis (pinworms)

BACKGROUND

Pinworms are the most common helminth infection in the USA and Western Europe, with prevalence rates in some communities of as high as 30-50%. Pinworms generally live in the gastrointestinal tract, and helminth infestations have been noted in over one-quarter of acute appendectomies on histologic examination.

RESULTS & CONCLUSIONS

Although transmission is often attributed to the ingestion of infective eggs by nail biting and inadequate hand washing, inhalation and ingestion of airborne eggs also occur. The female Enterobius vermicularis migrates nightly to the perianal area to deposit her eggs, but some worms find their way into adjacent orifices, most commonly the female genitourinary tract, producing an array of symptoms. More consideration of this entity is justified in patients presenting with genitourinary complaints not responding to normal therapies. In the treatment of pinworms affecting genitourinary organs, treatment with possibly two oral agents, namely mebendazole and ivermectin, and a topical therapy for the eggs may be warranted.

Growth of Enterobius vermicularis in a chimpanzee after anthelmintic treatment

The growth of Enterobius vermicularis in a chimpanzee was investigated by observing worms discharged in feces after administration of pyrantel pamoate. Just after the final molting, immature adult male pinworms developed to a fully mature stage in 2 wk, after passing through a stage corresponding to the so-called Enterobius gregorii, which was surmised to be a younger adult form of E. vermicularis. The frequency distribution of body length forms 2 peaks in both male and female pinworms, with a depression in the transitional forms from the immature to the fully mature stage. This depression seems to be the result of more rapid growth or lower susceptibility to the drug in this transitional stage. Pyrantel pamoate effectively eradicated mature males, but gravid females were continuously observed in the feces after treatment. The complete eradication of pinworm infection by pyrantel pamoate could be achieved by repeated treatment at intervals shorter than 2 wk. This treatment would eradicate male worms first, resulting in females producing only unfertilized eggs, from which only males might hatch.

[Field trials on the efficacy of albendazole composite against intestinal nematodiasis]

AIM

To study the anthelmintic effect of albendazole composite (containing 67 mg of albendazole and 83.3 mg base of pyrantel pamoate per tablet).

METHODS

A randomized controlled study was carried out to compare the efficacy of a single dose of 3 or 2 tablets of albendazole composite versus a single dose of 400 mg of albendazole or 10 mg base/kg of pyrantel pamoate for treatment of intestinal nematodiasis including 1,864 cases infected with hookworm, 1,568 cases infected with Ascaris, 1,785 cases infected with Tricuris trichiura and 373 children infected with Enterobius vermicularis.

RESULTS

In adults, the egg negative conversion rate of a single dose of 3 or 2 tablets of albendazole composite reached 65.0% and 52.7% for hookworm infection (P < 0.01), 100% and 100% for Ascaris infection, and 26.5% and 19.2% for Trichuris infection (P < 0.01), respectively. There were significantly better effect against hookworm with 3 tablets of albendazole composite than that with single albendazole or pyrantel pamoate (65.0% vs. 47.6% and 38.5%, P < 0.01). The effect of 2 tablets of albendazole composite against hookworm was also higher than that of single pyrantel pamoate (P < 0.01) and equal to single albendazole but the anthelmintic effect against Trichuris infection was lower than that of single albendazole (19.2% vs. 26.5%). In 2-6-year-old children, the effect of 1.5 tablets of albendazole composite against Enterobius vermicularis infection showed an egg negative conversion rate of 100% which was higher than that of single pyrantel pamoate (100% vs. 83.0%, P < 0.01). The worm collection data showed that the worm-expelling action of albendazole composite was much more rapid than that of albendazole. There were no adverse effects of albendazole composite on blood picture, liver or renal function and ECG. The side effect of both 3 and 2 tablets of albendazole composite was mild and transcient.

CONCLUSION

Albendazole composite exhibits a synergistic effect of both albendazole and pyrantel pamoate.

Chemotherapy of enterobiasis (oxyuriasis)

Enterobius vermicularis (syn. Oxyurus vermicularis), also known as pinworm or seatworm, is the causative agent of human enterobiasis (oxyuriasis). The disease is more prevalent in temperate regions and is facilitated by factors such as overcrowding in schools and family groupings, as well as inadequate personal and community hygiene. Although the infection is more likely to occur in lower socioeconomic groups, enterobiasis has been reported to affect virtually every level of the general population and especially children. In the great majority of cases, enterobiasis is asymptomatic. One common symptom is intense pruritus ani that in some patients can lead to insomnia, restlessness and irritability. Scratching may cause skin irritation, and in more serious cases, eczematous dermatitis, haemorrhage or secondary bacterial infections. Ectopic migration of E. vermicularis often results in pinworm infestation of the female genital tract often causing granulomas of the uterus, ovary and the fallopian tubes and pelvic peritoneum. Anthelmintic therapies for enterobiasis are successful and include mebendazole, albendazole and pyrantel pamoate. Mass medication of affected groups reduced symptoms rapidly, progressively and in a cost-effective way.

N3-arylspiroimidazolidine-2,4-diones N3-arylspiroimidazolidine-2-thio-4-ones and 4-hydroxy derivatives. Synthesis and anthelmintic activity

The synthesis of new N3-arylciclohexanespiroimidazolidine-2,4-diones, N3-arylciclohexanespiroimidazolidine-2-tio-4-ones and the 4-hydroxy derivatives is described and their structures discussed on the basis of I.R. and 1H-N.R.M. data. The anthelmintic activity of these compounds was tested.

The distribution and abundance of Enterobius vermicularis in a South Indian fishing community

The distribution and abundance of Enterobius vermicularis in a fishing community in South India, as determined by counting worms expelled following mass anthelmintic chemotherapy, was examined in samples of patients stratified by age, sex and family grouping. The results of a worm expulsion study in January 1984 are compared with those of a second expulsion programme in November 1984, following an 11-month period of reinfection. The prevalence of Enterobius infection was consistently high in all age groups of both males and females. A comparison of the overall prevalence and intensity of infection in the January and November surveys revealed significant increases in both the percent infected and the mean number of worms harboured in November relative to the initial level. No significant trends in the intensity of Enterobius according to host age or sex were detected in either survey. The frequency distribution of Enterobius was found to be highly aggregated in the population as a whole and within age groups. At both sampling dates, the most heavily infected 25% of the community harboured over 90% of the total pinworms recovered. There was a significant pattern within most age groups for individuals to re-acquire worm burdens of a similar magnitude to their initial pre-treatment burdens. Heavy infections were found to be associated with household. A selective or targetted approach to treatment of heavily infected individuals or households is likely to be an efficient means of reducing parasite abundance on a community-wide basis. It must be stressed, however, that treatment must be applied at frequent intervals in order to achieve a long-term reduction in pinworm abundance and to avoid the possibility of increasing the intensity of infection, as was observed in this community.