Oesophagostomiasis in non-human primates of Gombe National Park, Tanzania.

Oesophagostomum sp. is a parasitic nematode that frequently infects wild chimpanzees. Although nodular lesions are commonly associated with infection, some wild chimpanzee populations seem to tolerate Oesophagostomum nodular lesions while those at Gombe and other sites suffer from associated morbidity and mortality. From August 2004 to December 2013, we examined demographic (i.e., age, sex) and individual correlates (i.e., fecal consistency, Oesophagostomum egg production) to Oesophagostomum-associated pathology in 14 individually recognized chimpanzees at Gombe Stream National Park, Tanzania. In addition, we characterized Oesophagostomum-associated pathology in 14 individual sympatric primates including baboons, colobus, and cercopithecid monkeys. In five chimpanzees, there was no evidence of any significant underlying disease aside from oesophagostomiasis to explain the thin condition or diarrhea. All five of these chimpanzees had moderate to numerous parasitic nodules. In general, nodules were more numerous in older chimpanzees. Three of four chimpanzees with the highest average Oesophagostomum egg counts in feces collected during the year prior to their death had numerous parasitic nodules at necropsy. In contrast, the four chimpanzees with the lowest egg counts had only moderate numbers of nodules. No association (P = 0.74) was noted between frequency of diarrhea in the year prior to death and the number of nodules noted at necropsy. Nodules were also present in all baboons examined documenting pathology associated with Oesophagostomum infection in wild baboons. In contrast, no lesions were noted in colobus or cercopithecid monkeys, although it is uncertain if they are infected as no fecal studies have been completed in these species to date at Gombe. Sequence of DNA isolated from nodules in chimpanzees matched (99%) Oesophagostomum stephanostomum. Further research is needed to identify the types of Oesophagostomum causing lesions in baboons and to determine if baboons suffer from these infections. Am. J. Primatol. 80:e22572, 2018. © 2016 Wiley Periodicals, Inc.

Molecular identification of the strongyloid nematode Oesophagostomum aculeatum in the Asian wild elephant Elephas maximus.

The transmission of zoonoses by wildlife, including elephants, is a growing global concern. In this study, we screened for helminth infections among Asian wild elephants (Elephas maximus) of the Salakpra Wildlife Sanctuary, Kanchanaburi, Thailand. Elephant faecal samples (45) were collected from the sanctuary grounds during January through November 2013 and assayed individually using the tetranucleotide microsatellite technique. Microscopic examination indicated a high prevalence of strongylids (93.0%) and low prevalences of trichurids (2.3%) and ascarids (2.3%). To identify the strongylid species, small subunit (SSU) rDNA sequences were amplified from copro-DNA and compared with sequences in GenBank. The generated SSU-rDNA sequences comprised five distinct haplotypes that were closely related to Oesophagostomum aculeatum. A phylogenetic analysis that incorporated related nematodes yielded a tree separated into two main clades, one containing our samples and human and domestic animal hookworms and the other consisting of Strongyloides. The present results indicate that O. aculeatum in local elephants is a potential source of helminthiasis in human and domestic animals in this wild-elephant irrupted area.

Pathologic lesions in chimpanzees (Pan trogylodytes schweinfurthii) from Gombe National Park, Tanzania, 2004-2010.

During a population decline or disease outbreak, the true risk of specific diseases to a wild population is often difficult to determine because of a lack of baseline disease information. To better understand the risk of disease in an endangered and scientifically important population of chimpanzees (Pan trogylodytes schweinfurthii), a health monitoring program was initiated in Gombe National Park, Tanzania. As part of this health monitoring program, comprehensive necropsies with histopathology were conducted on chimpanzees (n = 11; 5 male, 6 female), ranging in age from fetal to 44 yr, that were found dead between August 2004 and January 2010. In contrast to previous reports, respiratory disease was not noted as a cause of morbidity or mortality. Trauma was the most common cause of death in these 11 chimpanzees. All of the chimpanzees greater than 1 yr of age had intestinal and mesenteric parasitic granulomas associated with true strongyles consistent with Oesophagostomum spp. The relative numbers of granulomas increased with age and, in some cases, may have been a cause of weight loss and diarrhea. Simian immunodeficiency virus (SIV)cpz infection was documented in four deceased apes, all of whom exhibited varying amounts of lymphoid depletion including two females with marked CD4+ T cell loss consistent with endstage SIVmac or human immunodeficiency virus infections. Myocardial megalokaryosis was common in chimpanzees greater than 1 mo of age; yet myocardial interstitial fibrosis, a common lesion in captive chimpanzees, was uncommon and only noted in two aged chimpanzees. These findings provide important information on causes of morbidity and mortality in wild chimpanzees, information that can be used to interpret findings during population declines and lead to better management of this population in the context of disease risk.

Clinical and pathologic manifestation of oesophagostomosis in African great apes: does self-medication in wild apes influence disease progression?

Nodular worms (Oesophagostomum spp.) are common intestinal parasites found in cattle, pig, and primates including humans. In human, they are responsible for serious clinical disease called oesophagostomosis resulting from the formation of granulomas, caseous lesions or abscesses in intestinal walls. In wild great apes, the fecal prevalence of this parasite is high, but little information is available concerning the clinical signs and lesions associated. In the present study, we describe six cases of multinodular oesophagostomosis in free-ranging and ex-captive chimpanzees and captive gorillas caused by Oesophagostomum stephanostomum. While severe clinical signs associated with this infection were observed in great apes raised in sanctuaries, nodules found in wild chimpanzees do not seem to affect their health status. One hypothesis to explain this difference would be that in wild chimpanzees, access to natural environment and behavior such as rough leaves swallowing combined with ingestion of plants having pharmacological properties would prevent severe infection and decrease potential symptoms.

Oesophagostomum bifurcum-induced nodular pathology in a highly endemic area of Northern Ghana.

Human infection with Oesophagostomum bifurcum is rare globally, but focally endemic and common in Ghana and Togo. Two clinical presentations are identified: uni-nodular disease, which may be recognized as a 'Dapaong Tumour', and multi-nodular disease. Here, we describe the prevalence of O. bifurcum infection and the association with nodular pathology in northern Ghana. The study was performed in October 2002. Out of a well-defined population of approximately 18000, 928 subjects of all ages were randomly selected for parasitological and ultrasound examination. In stool cultures, 44% had detectable third-stage O. bifurcum larvae present. Females were more often infected than males (P<0.05). In 34% of the samples, nodules were detected along the colon wall, with the ascending and the transverse colon being the most affected regions. Significant correlations existed between the intensity of infection and the presence of nodules, both at the village and the individual level (P<0.001 for both). Patients with multi-nodular pathology had significantly higher larval counts than patients with uni-nodular pathology. The present data suggest that nodular pathology, and probably the severity of the disease, are directly related to intensity of the infection.

Human oesophagostomiasis: a histomorphometric study of 13 new cases in northern Ghana.

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.

Ultrasonographic detection and assessment of preclinical oesophagostomum bifurcum-induced colonic pathology.

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.

Oesofagostomose experimental em bezerros / Experimental Oesophagostomosis in Calves

Foi promovida a infestaçäo experimental de dois grupos em seis bezerros mestiços zebu x holandês com 12 a 15 semanas de idade, com larvas infestantes de Oesophagostomum radiatum (Rudolphi, 1803). O grupo teste recebeu o total de 8 mil a 10 mil larvas infestantes por via oral. O período pré-patente variou entre 35 e 39 dias pós-infestaçäo, com o máximo de ovopostura ocorrendo entre a 6ª e a 8ª semana pós-infestaçäo. A anorexia foi responsável pela reduçäo no consumo de alimentos, tendo contribuído para a patogenia. Clinicamente os animais apresentaram anorexia, diarréia, hipertermia moderada, baixa conversäo alimentar e baixo ganho de peso, em comparaçäo com o grupo testemunha.

Ultrasound diagnosis of oesophagostomiasis.

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.

Dose related mucosal hyperplasia induced by Oesophagostomum dentatum infection in pigs.

The present work was undertaken to examine the effects of 3 different population densities of Oesophagostomum dentatum upon the development of worm induced mucosal changes in the colon following single infections. Groups of pigs were infected with single doses of 2000 (low dose), 20,000 (medium dose) or 200,000 (high dose) infective larvae, respectively. A total of 18 infected pigs (6 from each group) were examined for histopathological changes together with 3 helminth-free control pigs. There was a dose related difference in the intensity of colonic lesions; and using morphometry it was observed that the mucosal crypts of pigs in the high dose group were significantly longer than those in the 2 other groups. These differences disappeared by day 25 after infection despite the presence of larvae in the mucosa of the high dose group. This phenomenon may be related to inflammatory reactions in the colon, possibly in connection with the initiation of an immunological response in sites distant from the parasite larvae.

Oesophagostomiasis in man: report of the first Malaysian case with emphasis on its pathology.

This paper describes the first Malaysian case of oesophagostomiasis. The patient was an 8-year-old Malay boy who presented to Ipoh General Hospital, Perak with abdominal pain and weight loss. Examination revealed multiple cavitated pseudotumours of the colon. A hemicolectomy was performed. Examination of the lesions revealed Oesophagostomum worms in the necrotic centres. The differential diagnoses and the pathology caused by Oesophagostomum are discussed. A brief review of the available literature is presented.

[Dapaong "tumor". Helminthiasis caused by Oesophagostomum]. / La "tumeur" de Dapaong. Helminthiase à Oesophagostome.

28 cases of pseudotumors of the bowel, ileum and appendix by an infestation with Oesophagostomum bifurcum, a rare human parasite, are studied.

Neutrophilic nodules in the intestinal walls of Japanese monkeys associated with the neutrophil chemotactic activity of larval extracts and secretions of Oesophagostomum aculeatum.

High neutrophil chemotactic activity was detected in the culture medium from Oesophagostomum aculeatum larvae in vitro using blind-well chambers with Millipore filters, and guinea pig leucocytes as indicator cells. Neutrophil chemotactic activity was also detected in the extract from larval worms in a dose dependent fashion. This activity was detected in the low molecular weight fractions adjacent to a sodium chloride marker by gel filtration on Sephadex G200. These results were further confirmed with monkey neutrophils. The possible role of this activity in the formation of granulomatous lesions rich in neutrophils found in O aculeatum infections in the Japanese monkey is discussed.

Oesophagostomiasis in feral monkeys (Macaca mulatta).

For periods of 3, 6, and 12 months, 104 feral rhesus monkeys (Macaca mulatta) were on test. At the time of necropsy, 26 had caseous granulomatous lesions in the submucosa of the colon consistent with oesophagostomiasis. Five also had histologically identified granulomatous lesions without caseation of various colonic and more distant arterioles. The lesions were seen in the submucosa and subserosa of the colon, the kidney, the adventitial tissue of the prostate, the pancreas, and the heart. Presumptive evidence of the migration of the parasite was found in the adventitial tissue of the esophagus. Fragments of the larvae in arterioles and the caseous submucosa of the colon were consistent morphologically with the species Oesophagostomum. Acellular masses of what was interpreted as cuticle of a molting parasite were found in the lung. A mature female nematode was found encysted in the lung. The identity of that parasite and the cuticle has not been established.

Experimental infection of pigs with Oesophagostomum dentatum: pathogenesis and parasitology of repeated mass infection.

Pigs receiving a limited ration of 1 kg commercial feed per day were infected daily with 50,000 Oesophagostomum dentatum larvae. The animals exhibited serious diarrhoea and anorexia. Although there was neither anaemia nor hypoproteinaemia, there was a significant decrease in plasma sodium and an increase in blood urea nitrogen at the end of the experiment. Large numbers of third and fourth stage larvae were found in the ileal, caecal and colonic mucosae. Only fourth stage larvae, never adults, were observed in the lumen. A continual expulsion of large quantities of third and fourth stage larvae were demonstrated in the faeces beginning with the appearance of diarrhoea. Neither Vibrio coli, Salmonella spp nor Balantidium coli contributed to the course of the enteritis.

Oesophagostomiasis in man.

A case of oesophagostomiasis in an 8-years-old Africa girl is reported. The patient presented with abdominal pain and weight loss. Examination revealed multiple abdominal masses most of which were resected. The difficulties in differential diagnosis are discussed especially with reference to the need for increased awareness of this disease. The extant world literature on this subject is tabulated.

Disseminated oesophagostomiasis in the rhesus monkey.

Disseminated oesophagostomiasis was diagnosed at necropsy of 5 rhesus monkeys (Macaca mulatta). Nodular lesions were in visceral organs as well as in the colon and mesentery. Lesions varied greatly with respect to degree of organ involvement and damage due to parasite invasion. In 2 monkeys, nodular lesions were in the colon, mesentery, liver, kidneys, abdominal wall, urinary bladder, and uterus; in 1 of these 2 monkeys, a nodular lesion inhabited by a parasite was in a lung. The ectopic nodules in the less severely affected monkeys were scattered in the liver, kidneys, and abdominal wall.