Polyparasitism with Schistosoma mansoni,geohelminths, and intestinal protozoa in rural Côte d'Ivoire

Single species infections with schistosomes, geohelminths, and intestinal protozoans are common over large parts of sub-Saharan Africa, and it is expected that polyparasitism affects a considerable proportion of the population, hence posing a great toll on public health. However, few investigations have been carried out to quantify the extent of polyparasitism. Here, a detailed assessment is reported for the epidemiology of Schistosoma mansoni, geohelminths, and intestinal protozoan infections, with particular emphasis on polyparasitism among 260 community members in rural C?te d'Ivoire. Schistosoma mansoni, Entamoeba coli, and hookworm were the predominant species with prevalences of 71.5, 64.6, and 51.9%, respectively. Only 8 individuals displayed no infection, whereas two-thirds of the population harbored 3 or more parasites concurrently. There were a series of significant pairwise parasite co-occurrences, e.g., between S. mansoni and hookworms and between S. mansoni and E. coli. It is concluded that polyparasitism in the population studied here was very common, which is probably the case also in other areas of rural C?te d'Ivoire and elsewhere in sub-Saharan Africa. These findings call for integrated approaches to effectively control multiple parasitic and protozoan infections.     

Schistosomiasis,Soil-Transmitted Helminthiasis,and Sociodemographic Factors Influence Quality of Life of Adults in C?te d'Ivoire

Background

Burden of disease estimates are widely used for priority setting in public health and disability-adjusted life years are a powerful “currency” nowadays. However, disability weights, which capture the disability incurred by a typical patient of a certain condition, are fundamental to such burden calculation and their determination remains a widely debated issue.

Methodology

A cross-sectional epidemiological survey was conducted in the recently established Taabo health demographic surveillance system (HDSS) in south-central Côte d''Ivoire, to provide new, population-based evidence on the disability caused by schistosomiasis and soil-transmitted helminthiasis. Parasitological results from stool, urine, and blood examinations were juxtaposed to quality of life (QoL) questionnaire results from 187 adults. A multivariable linear regression model with stepwise backward elimination was used to identify significant associations, considering also sociodemographic characteristics obtained from the Taabo HDSS database.

Principal Findings

Prevalences for hookworm, Plasmodium spp., Trichuris trichiura, Schistosoma haematobium and Schistosoma mansoni were 39.0%, 18.2%, 2.7%, 2.1% and 2.1%, respectively. S. mansoni and T. trichiura infections of any intensity reduced the participants'' self-rated QoL by 16 points (95% confidence interval (CI): 4–29 points) and 13 points (95% CI: 1–24 points), respectively, on a scale from 0 (worst QoL) to 100 points (best QoL). The only other statistically significant effect was a 1-point (95% CI: 0.1–2 points) increase on the QoL scale per one unit increase in a calculated wealth index.

Conclusions/Significance

We found consistent and significant results on the negative effects of schistosomiasis and soil-transmitted helminthiasis on adults'' self-rated QoL, also when taking sociodemographic characteristics into account. Our results warrant further investigation on the disability incurred by helmintic infections and the usefulness of generic QoL questionnaires in this endeavor.     

Godrap Girls,Draou Boys,and the Sexual Economy of the Bluff in Abidjan,Côte d'Ivoire

In Abidjan, both economic and sexual exchanges are structured around the bluff, a mimetic performance of modern urban identity that is both a form of deception and a means of social transformation. Men and women attempt to seduce each other through the bluff and exploit the relationship for material gain. While marriage is held up as an ideal, it is increasingly elusive as kinship has come to mimic the peer networks of the informal economy. Like drag, the bluff collapses oppositions between appearance and reality, highlighting the performative aspects of ‘modernity’. I suggest that widespread urban sexual antagonism may be constructed around gendered performative consumption, such that the impossible demands of maintaining a deceptive appearance of success produces sexual exploitation and anxiety on both sides of the gender divide.     

Association of household demographic variables with child mortality in Côte d'Ivoire

The associations between household demographic variables and mortality of children aged less than five years were investigated using data from the 1998 Demographic and Health Survey (DHS) of the Republic of C?te d'Ivoire, Western Africa. Of the total of 1992 children born to women included in the study population during the 5-year period preceding the survey, 260 (13%) had died and 1732 (87%) were alive at the time of the survey. Logistic regression analyses used to compare biosocial variables between the deceased and living children showed that the sex of the child, birth interval and mother's occupation were associated with child's survival status. After adjusting for their effects, household demographic variables (i.e. number of household members, number of household members under 5 years [HM-5Y], number of household members 5 years or older [HM+5Y], the proportion of HM-5Y among all household members, and the ratio of HM-5Y to HM+5Y) were shown to be associated with the child's survival status. This study provided insight into the effects of intra-household competition among children and availability of care-givers as potential determinants of child survival. The results indicate that improvement of the childcare environment and reproductive intervention are necessary to reduce child mortality in West African countries.     

Nutrient fluxes in the shifting cultivation system of south-west Côte d'Ivoire

At two sites, one with a 4-year-old (4-Y) secondary vegetation and the other with a 20-year-old (20-Y) vegetation, the influence of burning slashed vegetation on crop performance was studied during three seasons. In the first season after clearing, also the influence on weed growth was studied. At both sites, burning significantly decreased the number of weed seedlings. The lowest number of seedlings was found on the burnt plots of the 20-Y site. Burning increased yield and nutrient uptake significantly in the first and second season after clearing. In the third season after burning, only at the 4-Y site a significantly higher yield and nutrient uptake were found. At the 20-Y site the effect had disappeared. Calculations of efficiency of utilization of absorbed N, P and K indicated that P was the least available nutrient, also after burning. At both sites three consecutive crops absorbed approximately 40% of P applied in ash, while the cumulative recovery of K was at least 36% at the 4-Y site and at least 59% at the 20-Y site. On non-burnt plots, yields were not lower in the third season than in the first season after clearing, thus indicating that the inherent soil fertility did not decrease. Hence, yield decline on the burnt plots could be ascribed to ash depletion. It was concluded that in the local shifting cultivation system, the combination of ash depletion and infestation of weeds are the main reasons for abandoning the fields.     

Barriers to HIV testing in Côte d'Ivoire: the role of individual characteristics and testing modalities

Background

Expanding HIV testing requires a better understanding of barriers to its uptake. We investigated barriers to HIV testing in Côte d''Ivoire, taking into account test circumstances (client vs. provider-initiated).

Methods

We used data from the 2005 nationally representative Demographic and Health Survey conducted in Côte d''Ivoire. Socio-demographic characteristics, sexual behaviour and knowledge and attitudes toward HIV/AIDS associated with recent (<2 years) HIV testing were identified using gender-specific univariate and multivariate logistic regressions. Among women, differential effects of barriers to testing according to test circumstance (whether they have been offered for a prenatal test or not) were assessed through interaction tests.

Results

Recent HIV testing was reported by 6.1% of men and 9.5% of women (including 4.6% as part of antenatal care). Among men, having a low socioeconomic status, having a low HIV-related knowledge level and being employed [compared to those inactive: adjusted Odds Ratio (aOR) 0.46; 95% confidence interval (CI) 0.25–0.87] were associated with lower proportions of recent HIV testing. Among women without a prenatal HIV testing offer, living outside the capital (aOR 0.38; CI 0.19–0.77) and reporting a unique lifetime sexual partner constituted additional barriers to HIV testing. By contrast, among women recently offered to be tested in prenatal care, none of these variables was found to be associated with recent HIV testing.

Conclusions

Various dimensions of individuals'' characteristics constituted significant barriers to HIV testing in Côte d''Ivoire in 2005, with gender specificities. Such barriers are substantially reduced when testing was proposed in the framework of antenatal care. This suggests that provider-initiated testing strategies may help overcome individual barriers to HIV testing.     

Interactions and Potential Implications of Plasmodium falciparum-Hookworm Coinfection in Different Age Groups in South-Central C?te d'Ivoire

Background

Given the widespread distribution of Plasmodium and helminth infections, and similarities of ecological requirements for disease transmission, coinfection is a common phenomenon in sub-Saharan Africa and elsewhere in the tropics. Interactions of Plasmodium falciparum and soil-transmitted helminths, including immunological responses and clinical outcomes of the host, need further scientific inquiry. Understanding the complex interactions between these parasitic infections is of public health relevance considering that control measures targeting malaria and helminthiases are going to scale.

Methodology

A cross-sectional survey was carried out in April 2010 in infants, young school-aged children, and young non-pregnant women in south-central Côte d''Ivoire. Stool, urine, and blood samples were collected and subjected to standardized, quality-controlled methods. Soil-transmitted helminth infections were identified and quantified in stool. Finger-prick blood samples were used to determine Plasmodium spp. infection, parasitemia, and hemoglobin concentrations. Iron, vitamin A, riboflavin, and inflammation status were measured in venous blood samples.

Principal Findings

Multivariate regression analysis revealed specific association between infection and demographic, socioeconomic, host inflammatory and nutritional factors. Non-pregnant women infected with P. falciparum had significantly lower odds of hookworm infection, whilst a significant positive association was found between both parasitic infections in 6- to 8-year-old children. Coinfected children had lower odds of anemia and iron deficiency than their counterparts infected with P. falciparum alone.

Conclusions/Significance

Our findings suggest that interaction between P. falciparum and light-intensity hookworm infections vary with age and, in school-aged children, may benefit the host through preventing iron deficiency anemia. This observation warrants additional investigation to elucidate the mechanisms and consequences of coinfections, as this information could have important implications when implementing integrated control measures against malaria and helminthiases.     

Effects of Forest Management on Diversity and Abundance of Fruit-feeding Nymphalid Butterflies in South-eastern Côte d'Ivoire

The effects of forest management on vegetation structure and capture frequencies of nymphalid butterflies were studied in a logged rain forest in south-east Côte d'Ivoire. An experimental compartment, where liberation thinning was carried out 3 years before, and a 5-year-old mono-dominant tree plantation were compared to a regenerating control compartment; 3642 specimens of 97 species were trapped. Accumulated species richness and diversity indices were lower in the control compared to the liberation thinning compartment, but lowest in the plantation. However, the habitat preference for traps situated in the control compartment was negatively correlated with the size of the species geographical range. Four out of five species with a lower capture frequency in the liberation thinning compartment showed preferences for mature succession stages and were either Upper Guinean endemics or Guinea–Congolian–restricted species. The seven species with higher capture frequencies in the liberation thinning compartment were all geographically widespread. Five of them showed higher frequencies in younger succession stages. Eight species, three canopy specialists and two Guinea savannah species, significantly preferred the plantation, while 17 species avoided this management type. Liberation thinning seems to affect the more specialised species with smaller geographic ranges, thus risking loss of regional diversity.     

Parasitic worms: knowledge, attitudes, and practices in Western Côte d'Ivoire with implications for integrated control

Background

In the developing world where parasitic worm infections are pervasive, preventive chemotherapy is the key strategy for morbidity control. However, local knowledge, attitudes, and practices (KAP) of parasitic worms are poorly understood, although such information is required for prevention and sustainable control.

Methods

We carried out KAP surveys in two rural communities of Côte d''Ivoire that were subjected to school-based and community-based research and control activities. We used qualitative and quantitative methods. The former included observations, in-depth interviews with key informants, and focus group discussions with school children and adults. Quantitative methods consisted of a structured questionnaire administered to household heads.

Principal Findings

Access to clean water was lacking in both communities and only a quarter of the households had functioning latrines. There was a better understanding of soil-transmitted helminthiasis than intestinal schistosomiasis, but community-based rather than school-based interventions appeared to improve knowledge of schistosomiasis. In the villages with community-based interventions, three-quarters of household interviewees knew about intestinal schistosomiasis compared to 14% in the village where school-based interventions were implemented (P<0.001). Whereas two-thirds of respondents from the community-based intervention village indicated that the research and control project was the main source of information, only a quarter of the respondents cited the project as the main source.

Conclusions/Significance

Preventive chemotherapy targeting school-aged children has limitations, as older population segments are neglected, and hence lack knowledge about how to prevent and control parasitic worm infections. Improved access to clean water and sanitation is necessary, along with health education to make a durable impact against helminth infections.     

Landscape diversity related to Buruli ulcer disease in Côte d'Ivoire

Background

Buruli ulcer disease (BU), due to the bacteria Mycobacterium ulcerans, represents an important and emerging public health problem, especially in many African countries. Few elements are known nowadays about the routes of transmission of this environmental bacterium to the human population.

Methodology/Principal Findings

In this study, we have investigated the relationships between the incidence of BU in Côte d''Ivoire, western Africa, and a group of environmental variables. These environmental variables concern vegetation, crops (rice and banana), dams, and lakes. Using a geographical information system and multivariate analyses, we show a link between cases of BU and different environmental factors for the first time on a country-wide scale. As a result, irrigated rice field cultures areas, and, to a lesser extent, banana fields as well as areas in the vicinity of dams used for irrigation and aquaculture purposes, represent high-risk zones for the human population to contract BU in Côte d''Ivoire. This is much more relevant in the central part of the country.

Conclusions/Significance

As already suspected by several case-control studies in different African countries, we strengthen in this work the identification of high-risk areas of BU on a national spatial scale. This first study should now be followed by many others in other countries and at a multi-year temporal scale. This goal implies a strong improvement in data collection and sharing in order to achieve to a global picture of the environmental conditions that drive BU emergence and persistence in human populations.     

Malaria transmission dynamics in central Côte d'Ivoire: the influence of changing patterns of irrigated rice agriculture

The dynamics of malaria transmission was studied comparatively in the villages of Zatta and Tiemelekro, central Cote d'Ivoire, from February 2002 to August 2003. Prominent agroecosystems in these villages are irrigated rice growing and vegetable farming, respectively. Mosquitoes (Diptera: Culicidae) were collected on human bait at night and by pyrethrum knock-down spray sheet collections at four randomly selected sentinel sites in each village. In 2002, for a total of 96 man-nights per village, 7716 mosquitoes were collected in Zatta and 3308 in Tiemelekro. In 2003, with half the sampling effort, 859 and 2056 mosquitoes were collected in Zatta and Tiemelekro, respectively. Anopheles gambiae Giles s.l. was the predominant mosquito and the key malaria vector throughout, followed by An. funestus Giles. Anthropophily among adult female Anopheles exceeded 95% in both villages. Comparison between years revealed that the biting rate of An. gambiae s.l. in Zatta decreased several-fold from 49.3 bites per person per night (b/p/n) in 2002 to 7.9 b/p/n in 2003 (likelihood ratio test (LRT) = 1072.66; P < 0.001). Although the biting rate remained fairly constant in Tiemelekro, the difference between years was significant (16.1 vs. 18.2 b/p/n; LRT = 148.06; P < 0.001). These observations were paralleled by a marked decrease in the infective rate of An. gambiae s.l. in Zatta (4.6-1.2%), and an increase in Tiemelekro (3.1-7.6%). Meanwhile, the entomological inoculation rate of An. gambiae s.l. decreased 21-fold in Zatta, from 789 to 38 infective bites per person per year (ib/p/y), whereas it remained high in Tiemelekro (233 vs. 342 ib/p/y). The interruption of irrigated rice growing in Zatta in 2003, consequential to a farmers' conflict over land, might be the underlying cause for the significant reduction in malaria transmission, whereas more stable conditions occurred in Tiemelekro.     

Risk factors and spatial patterns of hookworm infection among schoolchildren in a rural area of western Côte d'Ivoire

This study is aimed at investigating the risk factors for hookworm infection among schoolchildren in a rural area of western C?te d'Ivoire and predicting and mapping the spatial distribution of infection. We used demographic and socio-economic data from a cross-sectional survey of 6-16-year-old schoolchildren from 56 schools. Infection with hookworm was determined by microscopic examination of stool samples employing the Kato-Katz technique and an ether-concentration method. Environmental data were derived from satellite images and digitised maps. Bayesian variogram models were applied to investigate the variation of hookworm infection in relation to demographic, socio-economic and environmental factors. The overall hookworm infection prevalence, based on the pooled microscopic diagnoses, was 43.3% and ranged from 5.4 to 79.1% in the schools surveyed. Bivariate analyses showed that sex, age, socio-economic status, elevation, rainfall and land cover were significantly associated with the spatial distribution of hookworm infection. The final multivariate spatial model consisted of the covariates age, sex, socio-economic status, elevation and land cover. When assuming non-stationary underlying spatial dependency, the results of the model suggested that spatial correlation depended on the location only marginally. We conclude that, at the current resolution, it seems more reasonable to target interventions based on well-established epidemiologic risk factors, rather than on spatial factors.     

Short-Term Heart Rate Variability—Influence of Gender and Age in Healthy Subjects

In the recent years, short-term heart rate variability (HRV) describing complex variations of beat-to-beat interval series that are mainly controlled by the autonomic nervous system (ANS) has been increasingly analyzed to assess the ANS activity in different diseases and under various conditions. In contrast to long-term HRV analysis, short-term investigations (<30 min) provide a test result almost immediately. Thus, short-term HRV analysis is suitable for ambulatory care, patient monitoring and all those applications where the result is urgently needed. In a previous study, we could show significant variations of 5-min HRV indices according to age in almost all domains (linear and nonlinear) in 1906 healthy subjects from the KORA S4 cohort. Based on the same group of subjects, general gender-related influences on HRV indices are to be determined in this study. Short-term 5-min HRV indices from linear time and frequency domain and from nonlinear methods (compression entropy, detrended fluctuation analysis, traditional and segmented Poincaré plot analysis, irreversibility analysis, symbolic dynamics, correlation and mutual information analysis) were determined from 782 females and 1124 males. First, we examined the gender differences in two age clusters (25–49 years and 50–74 years). Secondly, we investigated the gender-specific development of HRV indices in five age decade categories, namely for ages 25–34, 35–44, 45–54, 55–64 and 65–74 years. In this study, significant modifications of the indices according to gender could be obtained, especially in the frequency domain and correlation analyses. Furthermore, there were significant modifications according to age in nearly all of the domains. The gender differences disappeared within the last two age decades and the age dependencies disappeared in the last decade. To summarize gender and age influences need to be considered when performing HRV studies even if these influences only partly differ.     

Differential response of seven duiker species to human activities in Taï National Park,Côte d'Ivoire

African rainforest is severely impacted by human activities, ranging from resource collection, selective logging to fragmentation and scale deforestation. Consequently, large mammal communities occurring therein are strongly modified. Here, we present a study conducted in Taï National Park (TNP), which characterises the spatial distribution and differential response of seven duiker species to human activities. Based on extensive survey data recorded between 2005 and 2015, we used a maximum entropy modelling approach for predicting duiker species distribution and a hierarchical clustering approach to identify potential subgroups in the duiker community. The seven duiker species clearly differed in their spatial distribution, with Cephalophus dorsalis and Philantomba maxwellii being the most common and widely distributed with no clear response towards gradients of impact from human activities. In contrast, Cephalophus ogilbyi, Cephalophus jentinki, Cephalophus sylvicultor and Cephalophus zebra showed increasing responses towards anthropogenic impact gradients, with the latter two being particularly sensitive. These duikers are not found in areas of illegal human activities. The restricted distribution of Cephalophus niger seems artificial and may indicate species misidentification. The strong spatial signature of human activities in the duiker community of TNP is of concern. Effective park management, including extensive ranger patrols, is vital for ensuring the persistence of this unique duiker community in West Africa.     

Census and distribution of chimpanzees in Côte D’Ivoire

Most methods of estimating chimpanzee population densities rely on nest counts. We tested the most frequently used techniques on a known chimpanzee community living in the rainforest of the Taï National Park, Côte d’Ivoire. The best density estimates are given by counts that assume groups of nests to be distributed randomly and that use the mean group size for homogenous habitat but the median for heterogenous habitats. Correction for real forest cover within the region should be made because chimpanzees make nests only in forested regions. This method gave the exact chimpanzee density for the Taï population, i.e. 1.7 nest builders/km². For the nationwide survey, we first estimated the chimpanzee density for different types of habitat (e.g. intact primary forest: 1.64 chimpanzees/km²; degraded forests: 0.4 chimpanzees/km²; human encroached forests and mosaic habitats: 0.09 chimpanzees/km²). Second, we estimated the total forest cover of the country with satellite pictures. This gave an estimated chimpanzee population in Côte d’Ivoire of about 11,676 ± 1,168 individuals, which equals the number of spectators at a soccer game in an average European town. Sadly, only three National Parks may have chimpanzee populations large enough to be viable, whereas the rest are scattered and isolated small populations that are already threatened in their survival.     

Ethanol production from pineapple juice in Côte d'Ivoire with preselected yeast strains

Fresh pineapple juice was inoculated with 8 preselected yeast strains and incubated for high yield ethanol production at between 25°C and 35°C.The natural pH of the juice did not affect the growth of the strains or the alcohol yields. The higher ethanol concentrations were obtained at 30°C and 35°C in the ranges of 27.17 to 46.50 g/l and 31.38 to 54.65 g/l, respectively, with 82% and 89% as the highest yields when referring to the theoretical yield.The study indicated that strain CMI is the best performing strain at 30°C and 35°C according to yield and productivity.