Tobacco smoking is associated with decreased semen quality.

BACKGROUND: Tobacco smoking is a public health issue and has been implicated in adverse reproductive outcomes including semen quality. Available data however provides conflicting findings. The objective of this study was to evaluate the effect of tobacco smoking on semen quality among men in Ghana. METHODS: In this study, a total of 140 subjects were recruited, comprising 95 smokers and 45 non-smokers. Smokers were further categorized into mild, moderate and heavy smokers. Semen parameters such as sperm concentration, motility, viability and normal morphology were measured according to the World Health Organisation criteria. RESULTS: The study showed that smokers had significantly lower semen volume, sperm concentration, sperm motility, total sperm count, sperm morphology, free testosterone and follicle stimulating hormone (p <0.05 respectively), compared with non-smokers. Smokers were at a higher risk of developing oligospermia, asthenozoospermia and teratozoospermia (OR = 3.1, 4.2 and, 4.7; p <0.05) than non-smokers. CONCLUSION: Results demonstrated a decline in semen quality in a dose dependent tobacco smoking manner.

Quality-quantity trade-off of human offspring under adverse environmental conditions.

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.

Mass treatment with albendazole reduces the prevalence and severity of Oesophagostomum-induced nodular pathology in northern Ghana.

Previous surveys conducted in northern Ghana where Oesophagostomum bifurcum is endemic showed that O. bifurcum-induced nodular pathology could be detected in up to 50% of the inhabitants. The impact of albendazole-based mass treatment to control both infection and morbidity is assessed and compared with the situation in a control area where no mass treatment has taken place. A significant reduction in the prevalence of infection based on stool cultures was achieved following two rounds of mass treatment in one year: from 52.6% (361/686) pre treatment to 5.2% (22/421) 1 year later (chi(1)(2)=210.1; P<0.001). At the same time, the morbidity marker of ultrasound-detectable nodules declined from 38.2% to 6.2% (chi(1)(2)=138.1; P<0.001). There was a shift from multinodular pathology, often seen in heavy infections, to uninodular lesions. In the control villages where no treatment took place, O. bifurcum infection increased from 17.8% (43/242) to 32.2% (39/121) (chi(1)(2)=9.6; P<0.001). Nodular pathology decreased slightly from 21.5% to 19.0%, but a higher proportion of these subjects developed multinodular pathology compared with baseline (chi(1)(2)=5.5; P=0.019). It is concluded that repeated albendazole treatment significantly reduces O. bifurcum-induced morbidity.

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.

Distribution and clustering of Oesophagostomum bifurcum and hookworm infections in northern Ghana.

Human Oesophagostomum infections are locally common in northern Ghana. The present study describes the results of a cross-sectional survey involving 1011 subjects, selected by a compound-based random sampling method from 1227 compounds in 24 villages. Selected persons were examined by both Kato and coproculture methods. Hookworm-like eggs, representing ova of Oesophagostomum bifurcum and hookworm were detected in 87.5% of the Kato smears. The geometric mean egg count of the infected subjects was 1018. Upon coproculture, third-stage larvae of O. bifurcum and hookworm were detected in 53.0% and 86.9% of subjects respectively. Oesophagostomum infections were clustered but no clear explanation for aggregation of infections could be found as yet. Subjects infected with hookworm had a 5-fold higher risk of being infected with O. bifurcum. Infection rates in adult women were higher than in adult men. No association was found with family size, level of hygiene or with the presence of animals in the compounds. Representatives of the Bimoba-tribe were significantly more infected than those of the other tribes. It appears, however, that this tribal association is a geographical phenomenon: Bimoba are mostly living in villages with the highest infection rates.

Annual mass treatment with albendazole might eliminate human oesophagostomiasis from the endemic focus in northern Ghana.

As a follow-up to the study by Ziem et al., in this issue, efforts to control human oesophagostomiasis and hookworm infections in northern Ghana were pursued, and the results evaluated in collaboration with the Lymphatic Filariasis Elimination Programme. This phase of evaluation of the impact of mass treatment was no longer limited to a small-scale research setting: it was done both in the context of an operationally viable national control programme and as a continuation of the Oesophagostomum Intervention Research Project (OIRP). The methods of evaluation included classical stool examination with Kato thick smears, stool culture and ultrasound examination of the colon wall. The results showed that yearly population-based albendazole-ivermectin treatment in 11 villages scattered over north-eastern Ghana, with a treatment coverage of 70-75%, resulted in a reduction of Oesophagostomum prevalence from about 20% pre-intervention to less than 1% after 2 years of mass treatment. Simultaneously, hookworm prevalence went down from 70% to approximately 15%. The data, however, cannot be readily compared with those of Ziem et al. because of the relatively crude diagnostic (single stool cultures) screening system that had to be used for the evaluation of the large-scale control programme. In the research area of the OIRP, interruption of mass treatment resulted in a rising hookworm prevalence. The Oesophagostomum prevalence, on the other hand, continued to go down. Transmission of human oesophagostomiasis appears interruptible and small numbers of persistent cases of Oesophagostomum infection were shown insufficient to serve as a nucleus of renewed spread of the infection. The data suggest that both the infection with and the pathology due to human oesophagostomiasis can be eliminated and that elimination is likely to be achieved through operationally feasible albendazole-ivermectin treatment as used by the Global Alliance for the Elimination of Lymphatic Filariasis.

The short-term impact of albendazole treatment on Oesophagostomum bifurcum and hookworm infections in northern Ghana.

In November-December 2002, stool samples from a random sample of the human population (N = 190) in the Garu area of northern Ghana were checked for intestinal helminths, using a single Kato smear and duplicate coprocultures for each subject. All 190 subjects were subsequently treated with a single, 400-mg dose of albendazole and 146 of them were successfully re-examined 21-28 days post-treatment. Prior to treatment, 75.5% of the Kato smears were found to contain 'hookworm-like' eggs (with a geometric mean egg count among the positives of 578 eggs/g faeces), and the third-stage larvae of Oesophagostomum bifurcum and hookworm were found in the cultures of stools from 34.2% and 77.4% of the subjects, respectively. Among the subjects who had positive Kato smears before treatment, albendazole treatment led to a cure 'rate' of 79.0% and an egg-reduction 'rate' of 73.5%. The results from the coprocultures indicated cure 'rates' of 98.0% for O. bifurcum but only 51.3% for hookworm. Only one subject was still positive for O. bifurcum after treatment. Among those still positive for hookworm after treatment, the larva-reduction 'rate' was 79.8%. The egg-/larva-reduction 'rates' among those with heavy infections prior to treatment were >90%, whether the data analysed came from the Kato smears or the coprocultures. It may be concluded that a single dose of albendazole is very likely to cure an O. bifurcum infection and to reduce greatly the intensity (but not the prevalence) of any hookworm infections.