Enterobius, trichuris, capillaria, and hookworm including ancylostoma caninum

Enterobius vermicularis (Pinworm) Appendicitis: The Real Vermiform Appendix

Enterobius vermicularis is the most common helminthic infection in the United States, infecting an estimated 40 million persons. A rare complication of E. vermicularis infestation is appendicitis. The diagnosis must be considered during pathologic examination to ensure appropriate treatment with anti-helminthic therapy.

Successful Resolution of Recurrent Vaginal Pinworm Infection With Intermittent Albendazole Administration

We describe the case of a 7-year-old girl with repeated vaginal Enterobius vermicularis infection, never detected as a digestive tract infection. Two-dose pyrantel pamoate or 2-dose albendazole could not suppress recurrence. Finally, 3-dose albendazole after 2-week intervals was successful in preventing relapse.

Enterobius vermicularis infection of the liver in a patient with colorectal carcinoma with suspected liver metastasis

A 68-year-old man diagnosed with cT3N2 adenocarcinoma of the rectum presented with a synchronous solitary liver metastasis on CT scan. Neoadjuvant chemoradiotherapy was started to downstage the primary tumour. Resection of the rectal tumour followed 3 months after the last radiotherapy session and primary resection of the isolated liver lesion was performed in the intervening period. Histopathological assessment of the liver lesion, however, showed no malignancy, but did reveal a necrotic infection due to Enterobius vermicularis. This parasite is frequently found in the intestines, but only rarely infects the liver. The patient was subsequently treated with the anthelmintic drug mebendazole 100 mg once a week for 2 weeks. Histopathological assessment of the rectal specimen showed complete regression after neoadjuvant chemoradiotherapy without evidence of remaining E. vermicularis, suggesting pinworm eradication. The patient recovered promptly after both surgical procedures.

Enterobius vermicularis infection of the ovary

Enterobius vermicularis is an intestinal parasite, which may occasionally involve extraintestinal sites including the female genital tract. We report a rare case of ovarian involvement, which presented with chronic right iliac fossa pain in a 31-year-old woman. A transvaginal ultrasound scan was suggestive of a right adnexal dermoid cyst; however, histological examination of the subsequent salpingo-oophorectomy specimen showed an abscess containing viable E. vermicularis ova. E. vermicularis is the most prevalent human nematode worldwide. Its ova are ingested, larvae hatch and mature female worms journey to the perianal region where they lay eggs. Female worms may also migrate from the anus along the female genital tract. Although of low pathogenicity, complications such as infertility or peritonitis may arise.

Neglected tropical diseases: survey and geometry of randomised evidence

OBJECTIVE

To assess the quantity and distribution of evidence from randomised controlled trials for the treatment of the major neglected tropical diseases and to identify gaps in the evidence with network analysis.

DESIGN

Systematic review and network analysis.

DATA SOURCES

Cochrane Central Register of Controlled Trials and PubMed from inception to 31 August 2011.

STUDY SELECTION

Randomised controlled trials that examined treatment of 16 neglected tropical diseases or complications thereof published in English, French, Spanish, Portuguese, German, or Dutch.

RESULTS

We identified 971 eligible randomised trials. Leishmaniasis (184 trials, 23,039 participants) and geohelminth infections; 160 trials, 46,887 participants) were the most studied, while dracunculiasis (nine trials, 798 participants) and Buruli ulcer (five trials, 337 participants) were least studied. Relative to its global burden of disease, lymphatic filariasis had the fewest trials and participants. Only 11% of trials were industry funded. Either a single trial or trials with fewer than 100 participants comprised the randomised evidence for first or second line treatments for Buruli ulcer, human African trypanosomiasis, American trypanosomiasis, cysticercosis, rabies, echinococcosis, New World cutaneous leishmaniasis, and each of the foodborne trematode infections. Among the 10 disease categories with more than 40 trials, five lacked sufficient head to head comparisons between first or second line treatments.

CONCLUSIONS

There is considerable variation in the amount of evidence from randomised controlled trials for each of the 16 major neglected tropical diseases. Even in diseases with substantial evidence, such as leishmaniasis and geohelminth infections, some recommended treatments have limited supporting data and lack head to head comparisons.

Pruritus ani: an approach to an itching condition

Pruritus ani is frequently encountered in children by the primary care physician and the pediatrician. It is mainly due to an infection with pinworms, but fecal soiling, poor hygiene, local irritation, and dietary agents should also be considered. Treatment should be directed at the underlying etiology. Once these have been excluded, both general and specific measures must be initiated. There is almost no experience for local treatment modalities in children, and they cannot currently be recommended.

The intestinal epithelium: sensors to effectors in nematode infection

The role of the intestinal epithelium as part of the physical barrier to infection is well established alongside its central roles in food absorption, sensing nutrients, and water balance. Nematodes are one of the most common types of pathogen to dwell in the intestine. This article reviews recent data that have identified crucial roles for intestinal epithelial cells in sensing these kinds of pathogens and initiating innate responses, which qualitatively influence adaptive immune responses against them. Moreover, it is now clear that the epithelium itself--in addition to the cells that lie within it--are key to many of the protective mechanisms that result in expulsion of these large multicellular parasites from the intestine. An understanding of the IEC and intraepithelial leukocyte response is crucial to both development of mucosal vaccines, and the mechanisms that underlie the emerging use of intestinal dwelling helminths for therapeutic treatments of inflammatory and autoimmune disease.

Parasitic colitides

Parasitic infections are a major worldwide health problem, and they account for millions of infections and deaths each year. Most of the infections as well as the morbidity and mortality from these diseases occur in the developing world in rural regions. However, these diseases have become more common in Western countries and in big cities over the past 25 years. These changing disease patterns can be attributed to emigration from the third world to developed countries and migration of rural populations to the big cities in developing nations. These parasitic infections have protean manifestations and consequences. The medical problems range from chronic asymptomatic carrier to fulminant infections and even death. Several factors such as the host immune status, the infecting organism, and the availability of treatment all play key roles in the outcomes of parasitic colitides. The two major classes of parasites causing these infections are the helminthes (ascariasis, strongyloidiasis, enterobiasis, trichuriasis, and schistosomiasis) and the protozoa (Isospora, Cryptosporidium, Cyclospora, Trypanosoma cruzi, Giardia lamblia, and Balantidium coli). This article summarizes the salient features of each parasite with respect to epidemiology, transmission, pathogenesis, clinical features, diagnosis, and treatment. The vast majority of these infections have a self-limited clinical course or are easily treated with medical management, and surgery is rarely needed.

New weapons in the war on worms: identification of putative mechanisms of immune-mediated expulsion of gastrointestinal nematodes

Parasitic nematode infections of humans and livestock continue to impose a significant public health and economic burden worldwide. Murine models of intestinal nematode infection have proved to be relevant and tractable systems to define the cellular and molecular basis of how the host immune system regulates resistance and susceptibility to infection. While susceptibility to chronic infection is propagated by T helper cell type 1 cytokine responses (characterised by production of IL-12, IL-18 and interferon-gamma), immunity to intestinal-dwelling adult nematode worms is critically dependent on a type 2 cytokine response (controlled by CD4+T helper type 2 cells that secrete the cytokines IL-4, IL-5, IL-9 and IL-13). However, the immune effector mechanisms elicited by type 2 cytokines in the gut microenvironment that precipitate worm expulsion have remained elusive. This review focuses on new studies that implicate host intestinal epithelial cells as one of the dominant immune effector cells against this group of pathogens. Specifically, three recently identified type 2 cytokine-dependent pathways that could offer insights into the mechanisms of expulsion of parasitic nematodes will be discussed: (i) the intelectins, a new family of galactose-binding lectins implicated in innate immunity, (ii) the resistin-like molecules, a family of small cysteine-rich proteins expressed by multiple cell types, and (iii) cytokine regulation of intestinal epithelial cell turnover. Identifying how the mammalian immune response fights gastrointestinal nematode infections is providing new insights into host protective immunity. Harnessing these discoveries, coupled with identifying what the targets of these responses are within parasitic nematodes, offers promise in the design of a new generation of anti-parasitic drugs and vaccines.

Adaptation of a nematode parasite to living within the mammalian epithelium

Trichuris muris is a large metazoan pathogen that has been proposed to live intracellularly within living host intestinal epithelial cells. We sought to determine how Trichuris bores its way through the mucosal epithelium and to elucidate the parasite strategies for taking advantage of this intracellular niche. Since the apical surface of the mucosal epithelium is stabilized by the actin cytoskeleton and cell junctions, it remains intact over the worm following its entry into cells. In contrast, non-stabilized lateral membranes of the host epithelial cells are ruptured and cells are killed to form an inert syncytial tunnel. The ventral surface of the nematode worm is studded by pores that overlie bacillary cells; these pores penetrate through the cuticle and are in direct contact with host cytoplasm. From scanning electron micrographs of isolated worms, we calculate that each adult contains approximately 50,000 bacillary cells. The apical surface of the bacillary cells is extensively folded into plicae 40 nm in diameter, thereby increasing the surface area many-fold. Bacillary cells lack organelles for enzyme synthesis and secretion and fail to export protons. However, by confocal light microscopy it was observed that fluorescent macromolecules in excess of 100,000 Da can penetrate into the pores. Taken together, we conclude that the bacillary cells are essential for living inside host epithelium and function predominantly in absorption of soluble molecules from the host mucosal cytoplasm, in essence behaving as an external gut epithelium that is protected from abrasion by the cuticle that surrounds the openings of the bacillary cells.

Enterobius vermicularis infection among population of General Mansilla, Argentina

AIM: To evaluate the relationships between the personal, sociocultural, and environmental characteristics, and the presence or absence of symptoms with the detection of Enterobius vermicularis (E. vermicularis) in a population sample in our region (General Mansilla, Province of Buenos Aires, Argentina), by individual and familiar analyses.

METHODS: E. vermicularis was diagnosed in 309 people from 70 family units residing in the urban area and the rural area of the city of General Mansilla. Each of them was surveyed so as to register personal, environmental and sociocultural data. Questions about the presence or absence of anal itch, abdominal pain and sleeping disorder were also asked. Significant associations were determined by square chi tests. Logistic regression models were adjusted by using a backward conditional stepwise method to determine the presence of this parasite in the individuals and in the families.

RESULTS: The parasites were found in 29.12% (90/309) of the individuals, with a frequency of 14.28% (20/140) among the heads of the families and of 41.42% (70/169) among the children. The only variables showing a significant association were affiliation, where the risk category was "being the son/daughter of", and the symptoms were abdominal pain, sleeping disorder, and anal itch. Families with a member infected with parasite were considered Positive Families (PF) and they were 40/70 (57.14%), only 5% (2/40) of the PF had 100% of their members infected with the parasite. The logistic regression models applied showed that the risk categories were mainly affiliation (son/daughter) and housing (satisfactory) among others.

CONCLUSION: The presence of E. vermicularis was proved in one third of the studied population. The frequency of families with all their members infected with the parasite was very low. Most of the studied personal, sociocultural, and environmental variables did not turn out to be significantly associated with the presence of the parasite. An association with the category of "son/daughter" and housing classified as "satisfactory" was determined. The latter may be due to the fact that the people living in that category of housing have hygienic practices at home that favour the distribution of the eggs in the environment. The presence of the analysed symptoms was associated with the presence of the parasite, thus strengthening the need of periodical control of the population showing at least one of these symptoms.

Differential requirement for NF-kappa B family members in control of helminth infection and intestinal inflammation

The NF-kappaB family of transcription factors is critical in controlling the expression of a wide range of immune response genes. However, whether individual family members perform specific roles in regulating immunity and inflammation remains unclear. Here we investigated the requirement for NF-kappaB1, NF-kappaB2, and c-Rel in the expression of Th2 cytokine responses, development of host protective immunity, and regulation of intestinal inflammation following infection with the gut-dwelling helminth parasite Trichuris muris. While mice deficient in c-Rel mounted sufficient Th2 responses to expel infection, NF-kappaB1 knockout (KO) and NF-kappaB2 KO mice developed chronic infections associated with elevated production of Ag-specific IFN-gamma. However, only infected NF-kappaB1 KO mice exhibited polarized IFN-gamma responses associated with the loss of intestinal goblet cells and the development of destructive colitis-like pathology. Furthermore, blockade of IL-12 (previously shown to confer resistance in susceptible strains) recovered Ag-specific IL-13 responses and resistance to infection in NF-kappaB2 KO, but not NF-kappaB1 KO mice. Therefore, unique infection, immunological, and pathological outcomes were observed in different NF-kappaB KO strains. Taken together, these results provide direct evidence of nonoverlapping functions for NF-kappaB family members in the development of Th2 cytokine-mediated resistance to T. muris and the control of infection-induced intestinal inflammation.

An Update on the Geohelminths: Ascaris lumbricoides, Hookworms, Trichuris trichiura, and Strongyloides stercoralis

Geohelminths remain prevalent throughout the developing world where levels of sanitation, personal hygiene, and maternal education are low. The five species of nematodes responsible for the bulk of disease are Ascaris lumbricoides, the hookworms Ancylostoma duodenale and Necator americanus, Trichuris trichiura, and Strongyloides stercoralis. Geohelminths are acquired through ingestion of fecally contaminated food or water or through contact with infected soil. In developing countries, infection with more than one nematode species and high worm burdens are common. The morbidity is substantial, particularly among children, and deaths occur. Geohelminthic infections are encountered in industrialized countries among immigrants and long-term travelers who have lived in endemic regions where sanitation is poor, and occasionally following autochthonous transmission.

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.

Epidemiology and control of enterobiasis in a developmental center

OBJECTIVE

To determine if enterobiasis could be controlled in a developmental center.

DESIGN

Population-based study. Annual screening of all residents by perianal swabs for enterobiasis and on admission or discharge. Treatment of infected residents and their contacts with mebendazole, 100 mg orally, with two doses given 14 days apart.

MAIN OUTCOME MEASURES

The number of residents with enterobiasis and the cost of the program.

RESULTS

The prevalence of enterobiasis fell rapidly and progressively, from 21% before mass medication to 1% after 3 years.

CONCLUSION

Mass medication of residents with enterobiasis and their contacts was beneficial, harmless, and cost effective.