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| {{Oesophagostomum}} | | {{Oesophagostomum}} |
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| | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
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| == Diagnostic tests ==
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| A definitive diagnosis of Oesophagostomum infection is traditionally done by demonstrating the presence of the larval or young adult forms in nodules of the intestinal wall via surgical examination of tissue. The larvae usually found in tissues can be 500 nanometers or longer in length.<ref>Ziem, J.B. “Controlling human oesophagostomiasis in northern Ghana.” (Doctoral thesis) Leiden University. 2006. <https://openaccess.leidenuniv.nl/dspace/handle/1887/4917?mode=more>.</ref> With microscopy, one can identify the larvae based on the presence of somatic musculature divided into four quarters, along with a multinucleated intestine as well as an immature reproductive system.<ref name="Sun, Tsieh 1999"/>
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| Laboratory methods are of little use for ''Oesophagostomum'' diagnosis. It is virtually impossible to make a diagnosis based on microscopy of stool samples alone, as Oesophagostomum eggs cannot be differentiated from hookworm eggs, which are often found in ''Oesophagostomum'' endemic areas.<ref name="Polderman, A. M. 1995"/> The only way to differentiate between the two species of eggs is to perform coproculture, which allows eggs to develop to their stage three larvae, although this is both time consuming and unreliable.<ref name="Gasser, R B 2006"/> Immunoassay tests like ELISA that monitoring for increases in IgG4 antibodies can indicate tissue invasion by ''Oesophagostomum''.<ref name="Polderman, A. M. 1995"/>
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| Recent advances, however, have allowed for less invasive and more accurate methods of diagnosis. The following is a review of three articles detailing the diagnostic use of PCR assays and sonographic imaging.
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| ''Verweij, Jaco J., Anton M. Polderman, et al. “PCR assay for the specific amplification of Oesophagostomum bifurcum DNA from human faeces.” International Journal for Parasitology 30.2 (2000): 137-142. '' This study developed a molecular-based approach to diagnosing oesophagostomiasis caused by ''O. bifurcum'' in humans. Using genetic markers in ribosomal DNA, the researchers developed PCR assays to selectively amplify ''O. bifurcum'' DNA from human fecal samples. These assays achieved sensitivity ratings of 94.6% and specificity of 100%, suggesting that the PCR method could be a viable alternative to the long-standing methods of diagnosis as well as an opportunity to reveal more about the epidemiology of oesophagostomiasis.<ref>Verweij, Jaco J., Anton M. Polderman, et al. “PCR assay for the specific amplification of Oesophagostomum bifurcum DNA from human faeces.” Int. J. Parasitol. 30.2 (2000): 137-142.</ref>
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| ''Storey, P A, S Anemana, et al. “Ultrasound diagnosis of oesophagostomiasis.” The Brit. J. of Radiol. 73.867 (2000): 328-32.''
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| Sonographic imaging and ultrasound were used to examine two cases of oesophagostomiasis in the [[Nalerigu hospital]] in northern Ghana. The technology allowed for the detection of intestinal and abdominal wall modules, as well as their size, type and location in the case of the ultrasound. Multinodular disease was representedby nodular colonic lesions and pseudokidney appearances, while the single-nodular Dapaong tumor had the appearance of an echo-free lumen surrounded by a defined but badly reflective wall. The ability to diagnose oesophagostomiasis via ultrasound can reduce the number of excessive invasive surgeries and put greater emphasis on chemotherapy.<ref>Storey, P A, S Anemana, et al. “Ultrasound diagnosis of oesophagostomiasis.” Brit. J. Radiol. 73.867 (2000): 328-32.</ref>
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| ''Verweij, Jaco J, Eric A T Brienen, et al. “Simultaneous detection and quantification of ''Ancylostoma duodenale'', ''Necator americanus'' and ''Oesophagostomum bifurcum'' in fecal samples using multiplex real-time PCR. (2007) Am. J. of Trop. Med. Hygiene 77 (4) 685-690''
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| A [[multiplex PCR]] method was developed for simultaneously detection of ''A. dudodenale'', ''N. americanus'' and ''O. bifurcum'' in human fecal samples. The method was tested on human fecal samples from an area in Ghana where co-infections with all three species are endemic. Results showed that the method was both highly specific and sensitive, attaining 100% specificity and sensitivities of 100%, 86.7%, and 100% for detection of ''N. americanus'', ''O. bifurcum'' and ''A. duodenale'' respectively. Furthermore, cycle threshold values, which correspond to parasite-specific DNA load, correlated with measured intensity of infection as demonstrated in Kato-Kato smears. This PCR method could potentially elucidate species-specific transmission pathways of hookworm-like infections and improve monitoring of interventions.<ref>Verweij, Jaco J, Eric A T Brienen, et al. “Simultaneous detection and quantification of ''Ancylostoma duodenale'', ''Necator americanus'' and ''Oesophagostomum bifurcum'' in fecal samples using multiplex real-time PCR.” Am. J. Trop. Med. and Hygiene 77.4 (2007): 685-690.</ref>
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| == Management and therapy ==
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| The typical adult therapy for oesophagostomiasis is a single 400 mg dose of [[albendazole]] (200 mg for children) or [[pyrantel pamoate]].<ref>“GIDEON Infectious Diseases - Diseases.” GIDEON Infectious Disease Database. 5 Feb 2009. <http://web.gideononline.com/web/epidemiology/index.php?gdn_form=ZGlzZWFzZT0xMTY1MA==>.</ref> Albendazole works by binding to the free beta tubulin, which inhibits tubulin polymerization. This results in the inhibition of glucose uptake by the Oesophagostomum. Albendazole and pyrantel pamoate at these doses have cure rates of 85% and 59-82%, respectively.<ref name="Sun, Tsieh 1999"/> Excision of ''Oesophagostomum'' larvae from nodules has been shown to have a curative effect on the patient but is invasive and more resource intensive than chemotherapy.<ref name="Sun, Tsieh 1999"/>
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| For oesophagostomiasis with complications, the type of treatment varies depending on the severity of the disease. Usually 200–400 mg of albendazole will be given immediately and continued for up to 5 days in conjunction with 250 mg dosages of amoxicillin.<ref>Ziem, J.B. “Controlling human oesophagostomiasis in northern Ghana.” (Doctoral thesis) Leiden University. 2006. <https://openaccess.leidenuniv.nl/dspace/handle/1887/4917?mode=more>.</ref>
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| In the case of formation of abscesses or fistulae arising from Dapaong tumors, incision and drainage is performed, followed by a regimen of albendazole and antibiotic treatment.<ref>Ziem, J.B. “Controlling human oesophagostomiasis in northern Ghana.” (Doctoral thesis) Leiden University. 2006. <https://openaccess.leidenuniv.nl/dspace/handle/1887/4917?mode=more>.</ref>
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| == Epidemiology ==
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| Oesophagostomiasis is endemic or potentially endemic to 35 countries; approximately 250,000 are infected worldwide, with 1 million more at risk according to the Gideon Infectious Diseases Database. Most of the cases originate in Africa, specifically in Ghana, Togo, [[Uganda]], Nigeria, [[Zimbabwe]] and other nearby countries. A few sporadic cases have been reported in countries in South America and Southeast Asia, including Brazil, Indonesia and [[Malaysia]].<ref>“GIDEON Infectious Diseases - Diseases.” GIDEON Infectious Disease Database. 5 Feb 2009. <http://web.gideononline.com/web/epidemiology/index.php?gdn_form=ZGlzZWFzZT0xMTY1MA==>.</ref> The vast majority of clinical cases have been collected from northern Togo and Ghana, in West Africa. 156 cases from the areas alone were collected in a 2000 study; before then, only 116 cases were recorded in the literature.<ref>“GIDEON Infectious Diseases - Diseases.” GIDEON Infectious Disease Database. 5 Feb 2009. <http://web.gideononline.com/web/epidemiology/index.php?gdn_form=ZGlzZWFzZT0xMTY1MA==>.</ref> ''O. bifurcum'' infection in northern Togo and Ghana is found in virtually every village, with some rural areas exhibiting as much as 90% prevalence.<ref name="Gasser, R B 2006"/>
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| <!-- Image with unknown copyright status removed: [[File:endemic area.jpg]] -->
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| Prevalence is higher in children between ages 2–10), and females older than 5 years of ages have higher prevalence than males within the same age group. These age demographic and gender discrepancies are not yet sufficiently explained – possible factors include differential exposure to contaminated water and strength of immune response.<ref name="Gasser, R B 2006"/>
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| A study done by Krepel in 1992 revealed a correlation between infection with ''O. bifurcum'' and ''N. americanus'' in that individuals living in endemic villages were either coinfected with both parasites or neither.<ref name="Krepel, H P 1992"/> This could be due to cofactors shared by both parasites, including poor hygiene, certain agricultural practices and the dearth of potable water suitable for consumption.
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| Below is a review of some epidemiological studies on the epidemiology of ''Oesophagostomum bifurcum'' in northern Togo and Ghana.
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| ''"Human Oesophagostomum infection in northern Togo and Ghana: epidemiological aspects." By: Krepel et al. Annals of Tropical Medicine and Parasitology.1992. 86:289-300.''
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| A regional survey of ''O. bifurcum'' infection was carried out in Togo and Ghana. The parasite was found in 38 of the 43 villages surveyed, with the highest prevalence rates reaching 59% in some small, isolated villages. Infection was found to be positively correlated with hookworm infection; however, the difficulty in distinguishing these parasites may have had some confounding effect. Infection rates were low in children under 3 years of age, beyond that, rates of infection increased dramatically until 10 years of age. Interestingly, females showed higher prevalence of infection (34%)than men (24%). Based on these epidemiological studies, this group was ale to conclude that tribe, profession, or religion had no effect on the prevalence of infection in the different communities surveyed. The habitats and life cycle of this parasite do not explain its distribution.<ref>"Human Oesophagostomum infection in northern Togo and Ghana: epidemiological aspects." By: Krepel et al. ''Annals of Tropical Medicine and Parasitology''.1992. 86:289-300.</ref>
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| ''"Clinical epidemiology and classification of human oesophagostomiasis." By: P.A. Storey et al. Trans R Soc Trop Med Hyg. 2000. 94:177-182.''
| | ==[[Oesophagostomum overview|Overview]]== |
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| The study investigated the clinical epidemiology of oesophagostomiasis by observing 156 cases in the Nalerigu hospital between 1996-1998. About 1 patient/week presented with this disease over the course of two years and 1% of all surgeries carried out were related to oesophagostomiasis. 13% of the patients presented with the multinodular form of the disease in which they had several nodules in their small intestine, abdominal pain, diarrhea, and weight loss. The other 87% of the patients presented with the Dapaong, or single, tumor form of the disease that was associated with inflammation in the abdomen, fever, and pain.<ref>"Clinical epidemiology and classification of human oesophagostomiasis." By: P.A. Storey et al. ''Trans R Soc Trop Med Hyg''. 2000. 94:177-182.</ref>
| | ==[[Oesophagostomum historical perspective|Historical Perspective]]== |
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| == Public health and prevention strategies/vaccines == | | ==[[Oesophagostomum classification|Classification]]== |
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| Given that infective ''Oesophagostomum'' larvae are most likely transmitted via oral-fecal routes, sufficiently cleaning and cooking meat and vegetables, as well as boiling all consumed water or only using potable water would help to complement a mass treatment program. Factors like religion, family size and wealth do not suffice in explaining the unique epidemiology of ''Oesophagostomum''; geographic and geological factors must be explored in more detail.<ref>Ziem, J.B. “Controlling human oesophagostomiasis in northern Ghana.” (Doctoral thesis) Leiden University. 2006. <https://openaccess.leidenuniv.nl/dspace/handle/1887/4917?mode=more>.</ref>
| | ==[[Oesophagostomum pathophysiology|Pathophysiology]]== |
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| Since oesophagostomiasis is primarily a regional problem (localized in northern Ghana and Togo, an optimal approach to addressing it requires mobilization of resources within and around the endemic area. One proposed solution is to organize all research and intervention projects at the local level, so as to instill knowledge of the infection in the community, and establish a regional collaboration between Ghana, Togo, and Burkina Faso in order to effectively combat oesophagostomiasis.<ref>Polderman, A. M., S. D. Anemana, and V. Asigri. “Human Oesophagostomiasis: A Regional Public Health Problem in Africa.” Parasitology Today 15.4 (1999): 129-130.</ref>
| | ==[[Oesophagostomum causes|Causes]]== |
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| There is no vaccine for oesophagostomiasis, although prolonged treatment with albendazole seems to be highly effective in countering the Oesophagostomum threat. In fact, recent research indicates that albendazole treatment may be the best intervention available for eliminating oesophagostomiasis from northern Togo and Ghana; following treatment, prevalence continued to go down even with interruption of the intervention. The following is a review of J. B. Ziem’s study of a mass treatment campaign in northern Ghana, as well as the follow-up conducted with the Lymphatic Filariasis Elimination Program.
| | ==[[Oesophagostomum differential diagnosis|Differentiating Oesophagostomum from other Diseases]]== |
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| Ziem, Juventus B et al. “Impact of repeated mass treatment on human Oesophagostomum and hookworm infections in northern Ghana.” Tropical Medicine & International Health: TM & IH 11.11 (2006): 1764-72.
| | ==[[Oesophagostomum epidemiology and demographics|Epidemiology and Demographics]]== |
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| This was a two year study, with four rounds of albendazole treatment administered to a village in Ghana; the target area and an untreated control area were monitored. In the target area, prevalence went down dramatically from 53.0% to 5.4% in the first year to 0.8% in the second year. Larval counts in stools also went down, as well as hookworm prevalence. In contrast, the control area saw an increase in prevalence from 18.5% to 37%. The results indicate potential for elimination of oesophagostomiasis utilizing similar albendazole-distributing mass treatment programs.<ref name="Ziem, J.B. 2006"/>
| | ==[[Oesophagostomum natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| Ziem, J. B. et al. “Annual mass treatment with albendazole might eliminate human oesophagostomiasis from the endemic focus in northern Ghana.” Tropical Medicine & International Health: TM & IH 11.11 (2006): 1759-63.
| | ==Diagnosis== |
| | [[Oesophagostomum history and symptoms| History and Symptoms]] | [[Oesophagostomum physical examination | Physical Examination]] | [[Oesophagostomum laboratory findings|Laboratory Findings]] | [[Oesophagostomum echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Oesophagostomum other imaging findings|Other Imaging Findings]] | [[Oesophagostomum other diagnostic studies|Other Diagnostic Studies]] |
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| This follow-up to the original two-year study by J.B. Ziem saw collaboration with the Lymphatic Filariasis Elimination Programme, essentially expanding the scope of the Oesophagostomum Intervention Research Program that Ziem worked under. 11 villages across northeastern Ghana were given albendazole-ivermectin treatment and monitored for changes in prevalence; once again, decreases in both ''Oesophagostomum'' and hookworm infections occurred after two years of mass treatment. However, after interrupting mass treatment, Oesophagostomum prevalence continued to decrease even as hookworm prevalence increased again. Human oesophagostomiasis infection thus seems interruptible; even small numbers of persistent Oesophagostomum post-treatment were not sufficient to cause reinfection.<ref>Ziem, J.B. et al. “Annual mass treatment with albendazole might eliminate human oesophagostomiasis from the endemic focus in northern Ghana.” Tropical Medicine & International Health: TM & IH 11.11 (2006): 1759-63.</ref>
| | ==Treatment== |
| | [[Oesophagostomum medical therapy|Medical Therapy]] | [[Oesophagostomum surgery|Surgery]] | [[Oesophagostomum primary prevention|Primary Prevention]] | [[Oesophagostomum cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Oesophagostomum future or investigational therapies|Future or Investigational Therapies]] |
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| ==References== | | ==Case Studies== |
| {{reflist|2}}
| | [[Oesophagostomum case study one|Case #1]] |
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| ==Online resources==
| | [[Category:Disease]] |
| *[http://www.stanford.edu/class/humbio103/ParaSites2002/oesophagostomiasis/Intro.html] - a free online compendium of all aspects of ''Oesophagostomum bifurcum'' biology
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| *[http://web.gideononline.com/web/epidemiology/index.php?gdn_form=ZGlzZWFzZT0xMTY1MA==] - Gideon Infectious Disease database entry on oesophagostomiasis
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| *[https://openaccess.leidenuniv.nl/dspace/handle/1887/4917?mode=more] - J.B. Ziem’s doctoral thesis on controlling human oesophagostomiasis in northern Togo and Ghana
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| *[http://www.ajtmh.org/cgi/pmidlookup?view=long&pmid=2035755] - A.M. Polderman’s review on human oesophagostomiasis
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| [[Category:Nematodes]] | | [[Category:Nematodes]] |
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