Infection with Oesophagostomum sp. is normally considered a rare zoonosis and up to this time its diagnosis has been based on the demonstration of larvae and young adult worms in the typical nodules formed in the intestinal wall. Only in Dapaong, in North Togo, and Bawku, North Ghana, have larger series of clinical cases been described. In the rural areas around these towns, a survey was made in which stool samples were collected and cultured. Third-stage larvae of Oesophagostomum sp. could be found after 5â€"7 days of incubation at room temperature, and the prevalence of infection with this parasite was often high but varied from one village to another. It was over 30% in seven villages out of the 15 villages surveyed. Anthelmintic treatment resulted in the evacuation of adult males and females of 0. bifurcum. It is concluded that 0. bifurcum is a locally common parasite of humans, not requiring an animal reservoir for completion of its lifecycle.

SummaryUntil recently infection of humans with Oesophagostomum bifurcum was regarded as a rare zoonosis. But in northern Togo and Ghana its prevalence is 50% or more in certain villages. Diagnosis is hampered by the fact that the eggs of O. bifurcum are morphologically identical to those of the hookworm Necator americanus. Stools have to be cultured for 7 days to allow eggs to hatch to the characteristic third-stage (L3) larvae. We evaluated the applicability of speci®c polymerase chain reactions (PCRs) to amplify DNA from faecal samples as an alternative method for the differential diagnosis of the two infections. Oesophagostomum bifurcum-PCR was positive in 57 of 61 faecal samples known to contain O. bifurcum L3 larvae in coproculture. Necator americanus PCR was positive in 137 of 146 faecal samples known to contain N. americanus L3 larvae in coproculture. PCR also detected 26 additional O. bifurcum cases in 72 samples from O. bifurcum endemic villages in which no O. bifurcum larvae were found and 45 N. americanus cases in 78 samples in which no N. americanus larvae were found in coproculture. No O. bifurcum DNA was detected in 91 stool samples from individuals from two non-endemic villages. These results prove the usefulness of speci®c PCR assays as epidemiological tools to estimate the prevalence of O. bifurcum and N. americanus infections in human populations.keywords Oesophagostomum bifurcum, Necator americanus, parasitic nematodes, diagnosis, speci®c diagnosis by PCR correspondence Jaco J. Verweij,

Infection with Oesophagostomum sp. appears to be extremely common in man in northern Togo and Ghana Adult specimens were recovered from the intestinal lumen by treatment with pyrantel pamoate and the morphological characteristics of oesophagostomes of man could for the first time be compared with information available on the morphology of oesophagostomes of monkeys. The observations and measurements demonstrated that the species involved is Oesophagostomum bifurcum and that the eggs of this species cannot be differentiated from those of Necator americanus. Both infections occur simultaneously in the population involved. The L1 larvae, too, cannot be differentiated from hookworm L1 larvae. The L3 however, are characteristic. Diagnoses of human Oesophagostomum infections is based on the detection of these larvae in coprocultures. In the present paper, the eggs, the L1 and L3 larval stages and the adults, carefully described and photos are given.

No abstract

Abstract. In contrast to the rest of the world, infections with Oesophagostomum bifurcum are commonly found in humans in northern Togo and Ghana. In addition, infections with hookworm are endemic in this region. In the present study, a detailed map of the geographic distribution of O. bifurcum and hookworm infections in northern Togo was made. There were a number of foci with high prevalence of infection with O. bifurcum. All the villages examined were infected with hookworm, and the distribution was quite patchy. Women were infected with O. bifurcum more often than men, while infections with hookworm were more prevalent in men than in women. The prevalence and intensity of infection with both parasites were clearly age-dependent. We estimate that more than a 100,000 people in Togo are infected with O. bifurcum and more than 230,000 are infected with hookworm.