Lassa Fever in Post-Conflict Sierra Leone

Background

Lassa fever (LF), an often-fatal hemorrhagic disease caused by Lassa virus (LASV), is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002) ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH) in an area with the world''s highest incidence of the disease.

Methodology/Principal Findings

Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs) in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone''s thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects.

Conclusions/Significance

Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for LF.     

Sex differences in the influence of mothers on the sociosexual preferences of their offspring

The extent to which "nurture" as opposed to "nature" determines behavior and sociosexual preferences in mammalian species is controversial although most recent interest has focused on genetic determinants. We report here that if sheep and goats are cross-fostered at birth, but raised in mixed-species groups, their play and grooming behavior resembles that of their foster rather than genetic species. There are no sex differences in effects on these behaviors, and other species-specific behavior patterns such as aggression, browsing, climbing, and vocalizations are unaffected. In adulthood, cross-fostered males strongly prefer to socialize and mate with females of their foster mother's species, even if raised with a conspecific of their own species. Castration within 2 days of birth slightly reduces the level of this altered social preference but mating preference following short-term testosterone treatment is the same as for gonadally intact animals. Cross-fostered females also show significant preference for socializing with females and mating with males of their foster mother's species, although this effect is weaker than that in both gonadally intact and castrated males. When cross-fostered animals are placed in flocks containing members of only their genetic species for 3 years, male social and mating preferences for females of their mother's species remain virtually unaffected. Females change to display an exclusive mating preference for members of their genetic species in 1-2 years although they still retain some social interest in female members of their foster species. Thus, there are clear sex differences in the impact of the emotional bond between a mother and her offspring in these mammals. Effects on males are strongest and irreversibly maintained even after altering their social environment, whereas those on females are weaker and mating preferences are clearly adaptable in the face of altered social priorities. These sex differences are presumably caused by pre-, or early postnatal, organizational effects of sex hormones on the brain.     

Treatment of onchocerciasis with ivermectin in Sierra Leone

Ivermectin chemotherapy is proving to be a major advance in the management of onchocerciasis. In this article, James Whitworth reviews the work done on onchocerciasis and ivermectin in Sierra Leone and examines the evidence that mass treatment might control the clinical features of the disease and its transmission in West Africa. Ivermectin is safe and effectively reduces microfilarial (mf) loads, with major improvement in some ocular manifestations o f disease. This alone makes mass distribution to communities at risk of blindness worthwhile, even though the impact on other clinical features is less clear cut. Repeated doses have a cumulative effect on adult worms, which may cause more reduction in transmission than hitherto thought likely.     

Haemonchosis in sheep and goats in Sierra Leone

The incidence of haemonchosis in sheep and goats in Sierra Leone showed a seasonal variation with a high peak in the dry season (October to January) and a low one from March to May. Mean relative densities were significantly higher in young hosts and showed two peaks, a high one from August to December and a low one from April to June while the mean relative densities of old hosts were low and exhibited an irregular seasonal pattern with no defined peaks. The peak seasons in young hosts coincided approximately with the dry and rainy seasons. Male hosts showed an overall higher but not a significant mean relative density than females but for most of the months mean relative densities of infection of female hosts were not significantly higher than those of males. The roles of climatic conditions and arrested development (hypobiosis) and self-cure and host age immunity on Haemonchus contortus worm burdens are discussed.     

Long-term consistency of diurnal-type preferences among men

Diurnal type (chronotype) differentiates individuals on an axis between the extremes of evening type to morning type. These diurnal-type preferences are thought to be relatively stable, but follow-up studies are sparse. The study aims were (1) to compare cross-sectional studies of diurnal type preferences between two decades and (2) to analyze the consistency of diurnal-type preferences using a longitudinal dataset. We analyzed a total of 18?087 adult males from four datasets with information on diurnal type and age. Of these, 2144 were available for survival analysis and 567 for analysis of longitudinal diurnal consistency. Diurnal type was assessed by asking the individual to what extent they would rate themselves a morning or an evening person, categorized into four groups. Statistical tests for stability of diurnal type were based on transition matrices and p values obtained using likelihood ratios. Cox regression was used to calculate the relative risk of all-cause mortality in each of the four diurnal type groups. After direct age standardization, 9.5% (95% CI: 9.0–10.1%) of participants in the four datasets were evening types. The cross-sectional data yielded that morning types were less common in the 2000s than two decades earlier. The longitudinal dataset revealed a significant shift from evening type to another type from 1985 to 2008 (p?=?0.002). The relative risk of all-cause mortality was 1.3-fold (95% CI: 1.0–1.6; p?=?0.05) higher for evening types compared to morning types. At the population level, eveningness appears to have become more prevalent over recent decades. However, on the individual level, the more morningness the chronotype, the more persistent it remains with aging.     

Sulphur oxidation in tidal mangrove soils of Sierra Leone

Summary Tidal mangrove soil contained about 17-mg/g (oven-dry soil) of oxidisable sulphur, of which about 9 mg was insoluble in acetone. Samples showed considerable variability and this was shown to be due to the fact that decayed wood in the soil was heavily impregnated with oxidisable sulphur, a high proportion of which was insoluble in acetone. It is suggested that this proportion was the polysulphide fraction.When the soil was dried, its pH value fell to 3.0 to 2.4 due to the activity of sulphur-oxidising bacteria. When the pH value of the soil fell below 3 a rapid decline in the number of the organisms present occurred, and it is suggested that this was due to the increase in the availability of ferric iron which also occurred below this pH value.CaCO₃ had two main effects on sulphur oxidation; one on the sulphur-oxidising bacteria, increasing or decreasing sulphur oxidation according to whether the pH value was moved into or out of their range of activity, and an inhibitory effect on pyrites oxidation. The results indicate that the pyrites fraction was not oxidised above pH 3 and that it was not involved in acid-formation. It is suggested that pyrites oxidation under the experimental conditions was a chemical reaction possibly involving ferric ions.The possible application of the results to the reclamation of saline mangrove swamps is discussed.     

Fungi associated with selected fermented foods in Sierra Leone

Summary The mycoflora of two popular fermented foodstuffs of Sierra Leone, ogi from maize (Zea mays L.) and foofoo from cassava (Manihot esculenta Crantz), were determined before, during and after fermentation. Maize kernels containedAspergillus flavus, A. ochraceus, A. tamarii andPenicillium citrinum. Aflatoxins B₁ and G₁ and ochratoxin A were extracted from these kernels. Fresh cassava tubers had no mycoflora but the stored fermented product, dry ball foofoo, containedA. flavus, A. ochraceus andP. citrinum. The participation of fungi in either fermentation process was not observed. Ogi and dry ball foofoo also contained trace amounts of aflatoxin G₁. In ogi, while the amount of ochratoxin A was much the same as on the maize kernels, significantly low amounts of aflatoxin B₁ were detected. In addition to the known mycotoxins, a number of unidentified fluorescent compounds were isolated only in maize and dry ball foofoo.

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Moisissures associées avec certains aliments fermentés au Sierra Leone

Résumé La mycoflore de deux aliments fermentés, populaires au Sierra Leone, l'ogi de maïs (Zea mays Linn) et le foofoo de manioc (Manihot esculenta Crantz) est déterminée avant, pendant et après fermentation. Les grains de maïs contiennentAspergellus flavus, A. ochraceus, A. tamarii etPernicillium citrinum. On a extrait les aflatoxines B₁ et G₁ ainsi que l'ochratoxine A de ces grains. Les tubercules frais de manioc n'ont pas de mycoflore mais le produit fermenté conservé, le foofoo dry ball, contientA. flavus, A. ochraceus etP. citrinum. La participation des moisissures n'a été observée dans aucun des deux processus de fermentation. L'ogi et le foofoo dry ball contiennent aussi des traces d'aflatoxine G₁. Dans l'ogi, la quantité d'ochratoxine A est quasi la même que dans les grains de maïs, tandis que l'aflatoxine B₁ est déteetée en quantité significativement moindre. En plus des mycotoxines connues, un certain nombre de composés fluorescents non-identifiés ont pu être isolés mais seulement du maïs et du foofoo dry ball.

     

Economic Importance of the Medicinal Plant Trade in Sierra Leone1

Economic Importance of the Medicinal Plant Trade in Sierra Leone. This study identified, quantified, and evaluated the economic importance of the medicinal plant trade in Sierra Leone so that recommendations for conservation could be made. We carried out a quantitative market survey. We interviewed 120 vendors in three major cities and all vendors in two towns near a national park. Apart from the semistructured interviews, specimen samples were collected and identified, prices noted, and sales units measured. More than 40 species were traded in urban markets, nine species being the most frequently traded in all three cities. Only two plants were traded in the towns: Xylopia aethiopica (Dunal) A.Rich.and Garcinia kola Heckel. Most plants were traded in the form of dried bark or leaves. It was estimated that at least USD 64,000 are being annually traded in informal markets in major cities, the nine species most frequently traded contributing most of the retail value. Little information was found on import/export figures. Results from this study indicate that the trade of certain medicinal plants could be promoted as an alternative livelihood strategy for edge communities of protected areas. However, more information is needed on harvesting techniques, source and abundance of the species traded.     

Medicinal Plant Trade in Sierra Leone: Threats and Opportunities for Conservation

This study used a quantitative market survey to examine the ecological importance of the medicinal plant trade in Sierra Leone and the existing trading systems, so that it could be determined (1) if trade has a negative impact on the species traded, and/or (2) if trade could be used to support conservation projects. We interviewed vendors in three major cities and two towns and carried out focus–group discussions among collectors at forest edge communities. In the markets, specimen samples were collected and identified. In several forests, observations were made on harvesting techniques and relative abundance. More than 40 species are traded in urban markets, nine of which are the most frequently traded. Some plants are transported great distances to reach the urban markets, especially Xylopia aethiopica (Dunal) A.Rich. and Garcinia kola Heckel. Certain species might not be sustainably harvested depending on the collector practices (e.g., ring debarking, tree felling), and this might threaten these species, especially Piper guineense Schumach. & Thonn. However, results also suggest that the trade of some species could be promoted as an alternative livelihood strategy for edge communities of forest reserves. In this latter case, special attention should be paid to sustainable harvesting techniques.