Schistosomiasis in travelers often remains unrecognized because doctors are unfamiliar with the clinical presentation and diagnosis of this imported disease. We describe the epidemiological, clinical, and laboratory characteristics associated with an outbreak of schistosomiasis among nonimmune travelers. Of 30 travelers in two consecutive groups, 29 who had swum in freshwater pools in the Dogon area of Mali, West Africa, were followed for 12 months. Twenty-eight (97%) of those 29 became infected; 10 (36%) of the 28 had cercarial dermatitis, and in 15 (54%), Katayama fever developed. Eggs were found in 22 (79%) of the infected travelers: eggs of Schistosoma mansoni or terminally spined eggs (probably of Schistosoma intercalatum) were in the stools of 19 and 10 patients, respectively, and eggs of Schistosoma haematobium were in the urine of 7 patients. The eggs of 2 of these Schistosoma species were present in 6 cases, and in 4 cases eggs of all 3 species were found. The limited exposure of this group of travelers resulted in a high rate of infection with all three of the Schistosoma species that are prevalent in Africa. A diagnosis of schistosomiasis should be considered for any traveler with a history of exposure to fresh water in an area of endemicity. The only effective method of prevention is avoiding all contact with fresh water in these areas.

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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.

A central paradigm in life‐history theory is the trade‐off between offspring number and quality. Several studies have investigated this trade‐off in humans, but data are inconclusive, perhaps because prosperous socio‐cultural factors mask the trade‐off. Therefore, we studied 2461 offspring groups in an area under adverse conditions in northern Ghana with high fertility and mortality rates. In a linear mixed model controlling for differences in age and tribe of the mother and socioeconomic status, each additional child in the offspring group resulted in a 2.3% (95% CI 1.9–2.6%, P < 0.001) lower proportional survival of the offspring. Furthermore, we made use of the polygamous population structure and compared offspring of co‐wives in 388 households, thus controlling for variation in resources between compounds. Here, offspring survival decreased 2.8% (95% CI 2.3–4.0%, P < 0.001) for each increase in offspring number. We interpret these data as an apparent quality–quantity trade‐off in human offspring.