-
[show abstract]
[hide abstract]
ABSTRACT: Infection by the nematode Oesophagostomum bifurcum is focally distributed in Africa and causes a syndrome of abdominal pain, obstruction, or abdominal mass because of its predilection for invasion of colonic mucosa. To determine the reliability of ultrasound for the detection of colon pathology induced by this parasite, three studies to assess the intraobserver and interobserver variation of the technique were performed. In an area of northern Ghana endemic for O. bifurcum, 181 people from a low-prevalence village and 62 people from a high-prevalence village were examined twice by the same observer, and 111 people were independently examined by two observers in a moderately endemic village. The kappa statistics for the prevalence observations in the three studies were 0.82, 0.87, and 0.81, respectively, and kappa values for the intensity observations were 0.66, 0.63, and 0.71, respectively. The upper 95% confidence intervals of the average absolute difference in nodule size measurements in Study 1 and Study 3 were 3.6 and 4.5 mm, respectively. Therefore, ultrasound is useful in the diagnosis and management of O. bifurcum colon infection.
The American journal of tropical medicine and hygiene 01/2003; 67(6):680-3. · 2.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In northern Ghana and Togo, Oesophagostomum bifurcum infects an estimated 250,000 people, as determined by cultures of stool samples. The juvenile stages of the helminth develop within colonic wall nodules, causing Dapaong tumor or multinodular disease, at the rate of 1 case per week at Nalerigu Hospital in Ghana. Our aim was to discover whether suspected colonic-wall pathology is ultrasonographically visible in asymptomatic individuals living in the area where O. bifurcum is endemic. A total of 464 persons from 3 villages, ranging from highly infected to noninfected, were examined with ultrasonography. Anechogenic colonic lesions with posterior wall enhancement were observed in 71 (54.2%) of 131 and 57 (24.5%) of 233 persons from the villages of endemicity, and no lesions were seen in persons from the village outside the area of endemicity. We describe the lesions noted in this study as nodules caused by O. bifurcum, on the basis of their association at a population level with prevalence of larvae in stools, their expected ultrasonographic appearance and distribution (on the basis of our surgical experience with oesophagostomiasis), and the lack of a convincing differential diagnosis.
Clinical Infectious Diseases 08/2001; 33(2):166-70. · 9.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Oesophagostomiasis is an infrequently described and recognised parasitic infection in humans, caused by Oesophagostomum bifurcum. Although the disease is most often found in the northern part of Togo and the neighbouring part of Ghana, sporadic cases have been described in other parts of Africa and in Asia and South America: Uganda, Ivory Coast, Sudan, Kenya, Ethiopia, Indonesia, Malaysia and Brazil. Infection probably occurs by way of the ingestion of L3 larvae. These larvae penetrate the intestinal wall, especially that of the colon. Some of these larvae develop into young adult worms and return to the bowel lumen. Other larvae, however, develop into immature worms, which fail to settle in the lumen, forming abscesses in the bowel wall and causing pathology. In the literature 105 human cases have been described, many originating in the northern regions of Ghana and Togo. The present study was performed to evaluate 13 new cases originating in the northern part of Ghana (7 female and 6 male patients, aged between 2 and 60 years). Histopathologically, the patients could be divided into two groups: the first group showed multinodular disease, while patients in the second group presented with a single, nodular mass. In the first group, abscesses were seen throughout the colonic wall. The mean size of the cavities was 4.3+/-0.7 mm. There was no relation between the size and the localisation in the colonic wall. Abscesses were significantly larger in male patients than in female patients. There was no correlation with age. In the second group, histopathological examination showed a cyst of variable wall thickness with very limited inflammation. These cysts represented older lesions, often encapsulated in the mesentery. In conclusion, in this study we present 13 new cases of human oesophagostomiasis. The abscess formation was found to be organ specific, independent of age, and gender-related, producing a more intense tissue reaction in male patients.
Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 08/2001; 439(1):21-6. · 2.49 Impact Factor
-
Gut 05/2001; 48(4):565-6. · 10.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Ultrasonography has already revealed that up to 50% of individuals in some villages in northern Ghana have colonic pathology induced by Oesophagostomum bifurcum. Approximately 2% of those affected progress to clinical oesophagostomiasis if left untreated. In the present study, ultrasound-positive children living in a heavily infected community were each given 5 days of treatment with albendazole (10 mg/kg.day), early in the dry season. Treatment reduced the prevalence, number, size and half-life of the ultrasound-visible nodules, stopped the excretion of O. bifurcum eggs, and reduced the development of clinical oesophagostomiasis during the subsequent 8 months. However, the treatment had no impact on the new infections that occurred during the following rainy season, and no impact on nodule prevalence by the end of that rainy season. Surgical management may not be essential in non-acute cases of clinical oesophagostomiasis, as albendazole may kill the nodule-dwelling worms.
Annals of Tropical Medicine and Parasitology 02/2001; 95(1):87-95. · 1.43 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We conducted a study in an endemic area of both Oesophagostomum bifurcum and Necator americanus in northern Ghana to examine the possibility of pigs acting as transport hosts for these two human helminth species, due to the commonly observed coprophagic habits of pigs. Under controlled conditions four parasite-free pigs consumed fresh faeces from people heavily infected with both helminths, and faeces were subsequently collected from the rectum of the pigs from 5 to 50 h post-feeding. Four to five per cent of the O. bifurcum and N. americanus eggs fed to the pigs were viable and retrieved as third-stage larvae after coproculture of the pigs' faeces. We discuss the possible impact of the coprophagic habits of pigs as potential parasite transport hosts during different seasons in this area of West Africa.
Acta Tropica 10/2000; 76(2):125-30. · 2.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Human infection with Oesophagostomum bifurcum, a parasitic intestinal helminth, is endemic in parts of West Africa. Oesophagostomum bifurcum juveniles develop in the colonic wall, causing pus-filled granulomas. The pathology has two distinct forms. Multinodular oesophagostomiasis comprises hundreds of small nodules within a thickened, oedematous wall of the large intestine. Uninodular oesophagostomiasis, called the Dapaong tumour, presents as a painful 30-60 mm granulomatous mass in the abdominal wall or within the abdominal cavity. Diagnosis of oesophagostomiasis on clinical grounds alone is difficult. We describe cases illustrating the ultrasound appearance of these two presentations. Multinodular disease shows nodular "target" and "pseudokidney" colonic lesions. The Dapaong tumour is an echo-free ovoid lumen enveloped within a well defined poorly reflective wall.
British Journal of Radiology 04/2000; 73(867):328-32. · 1.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We exploited the high resolution capacity of polymerase chain reaction (PCR)-coupled single-strand conformation polymorphism (SSCP) to screen for sequence variation in the second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA) among 77 individuals representing Oesophagostumum bifurcum from human or Mona monkey hosts from Africa. SSCP analysis revealed distinct profiles among some of the individuals, and sequence analysis of representative samples defined different ITS-2 sequence types attributable to polymorphism at particular nucleotide positions. However, there was no unequivocal sequence difference between O. bifurcum individuals from humans and that from monkeys. This provided some support for the hypothesis that the parasite from the two hosts represents a single species and that the sequence microheterogeneity detected in the ITS-2 rDNA region represents population variation, although the findings were insufficient to reject the proposal that the parasite represents different species. Overall, the results showed the usefulness of the SSCP-sequencing approach for studying the genetic variation in O. bifurcum populations and indicated its potential to study macromolecular evolution and elucidate population differentiation at the molecular level.
Electrophoresis 07/1999; 20(7):1486-91. · 3.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An estimated 250,000 people in northern Ghana and Togo are infected with the intestinal helminth parasite Oesophagostomum bifurcum, as detected by stool cultures. Clinical disease caused by O. bifurcum is responsible for about 50 cases per year at the region's central hospital, and presents as painful abdominal masses: inflammatory colonic nodules containing live juvenile stages of the helminth. In individuals living in villages highly endemic with O. bifurcum infection, colonic pathology visible by ultrasound is also highly prevalent. These nodules also contain O. bifurcum juvenile worms but are apparently asymptomatic. Thus, O. bifurcum infection and asymptomatic colonic pathology are highly prevalent within this area, but clinical disease is relatively uncommon. The natural evolution and regression of the colonic pathology in an endemic community in northern Ghana and its distribution within the population is described. Of the 299 individuals in the study group, 28% had colonic pathology at recruitment in the late-rainy season, which decreased with a half-life of 3-4 months during the dry season. Of those negative at recruitment, 28% developed nodules during the year, the majority appearing at the end of the subsequent rainy season. Children tended to have a higher prevalence and intensity of ultrasound-visible pathology compared to adults. Almost half (49%) of the study group had colonic nodules at least once during the year, and 2% of these individuals presented with clinical disease to the local hospital during the mid-rainy season.
Transactions of the Royal Society of Tropical Medicine and Hygiene 95(3):295-9. · 2.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The intestinal helminth Oesophagostomum bifurcum is highly and focally endemic in northern Ghana and Togo, and its juveniles produce a nodular inflammatory response as they develop in the intestinal wall. This pathology can produce clinical symptoms. We report on 156 cases of oesophagostomiasis presenting in 1996-98 to Nalerigu hospital in northern Ghana. The disease accounted for 0.2% of the out-patient department new presentations (about 1 patient per week), and 1% (16) of the major acute surgical cases. Children aged 5-9 years were most commonly affected. Multinodular disease (13% of the cases) results from hundreds of pea-sized nodules within the colon wall and other intra-abdominal structures, and presents with general abdominal pain, persistent diarrhoea and weight loss. Dapaong tumour (87%) presents as an abdominal inflammatory mass often associated with fever. The 3-6-cm tumour is painful, well-delineated, smooth, spherical, 'wooden', periumbilical, and adhered to the abdominal wall. Cases most commonly presented during the late rains and early dry season. Diagnosis by ultrasound has reduced the need for exploratory surgery, and the ability to sonographically evaluate conservative treatment with albendazole has curtailed management by colectomy or incision and drainage.
Transactions of the Royal Society of Tropical Medicine and Hygiene 94(2):177-82. · 2.16 Impact Factor
