Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire

Only pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m(-2) bifenthrin, 300 mg m(-2) carbosulfan, a mosaic of 300 mg m(-2) carbosulfan on the ceiling and 50 mg m(-2) bifenthrin on the sides, and a mixture of 6.25 mg m(-2) carbosulfan and 25 mg m(-2) bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.     

Adenovirus in Rural Côte D`Ivoire: High Diversity and Cross-Species Detection

The Taï region in Western Côte d`Ivoire is characterized by extensive overlap of human and animal habitats. This could influence patterns of adenovirus transmission between humans and domestic animals. Fecal samples from humans and various domestic animals were tested for the presence of adenoviruses by PCR. Phylogenetic and species delineation analyses were performed to further characterize the adenoviruses circulating in the region and to identify potential cross-species transmission events. Among domestic animals, adenovirus shedding was frequent (21.6% of domestic mammals and 41.5% of chickens) and the detected strains were highly diverse, several of them representing novel types. Although no evidence for zoonotic transmission of animal adenovirus was obtained, the present study provides concordant evidence in favor of common cross-species transmission of adenoviruses between different animal species and first indications for adenovirus transmission from humans to animals. These findings underline the thus far underestimated importance of reverse zoonotic transmission of viruses and of the role of domestic animals as pathogen reservoirs, “bridge species,” or intermediate hosts.     

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.     

How Mosquito Age and the Type and Color of Oviposition Sites Modify Skip-Oviposition Behavior in Aedes aegypti (Diptera: Culicidae)?

To address how physiological age, container type and the number of substrates affect Aedes aegypti skip-oviposition behavior, we examined egg distribution by individual females across consecutive gonotrophic cycles. We found no support for the effect of age on egg distribution. However, the hypothesis that both the variety and color of the container would influence skip-oviposition behavior was confirmed. Skip-oviposition behavior remained unchanged throughout the female’s life. The egg distribution pattern was characterized by a significantly higher oviposition rate in one site, with residual eggs distributed in groups of 1–30 eggs. Regardless type, most eggs were registered in dark containers. These data suggest that females contribute equally to population dynamics throughout their lifespan and illustrates the impact of color on egg dispersion.     

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.     

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.     

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.     

Zooplankton food limitation and grazing impact in a eutrophic brackish-water tropical pond (Côte d'Ivoire, West Africa)

Gut fluorescence, feeding and egg production rates of zooplankton assemblages were measured in a shallow, eutrophic brackish-water pond for 24 days. Brachionus plicatilis, Hexarthra intermedia and Apocyclops panamensis successively developed and exhibited differences in food selectivity. Rotifers selected small particles but also had a preference for larger particles (15–21 μm, Equivalent Spherical Diameter, ESD). B. plicatilis appeared less selective than H. intermedia, which fed mostly on particles <6 μm. A. panamensis adults showed a selectivity for 6–21 μm ESD particles. Laboratory experiments suggested that A. panamensis adults were able to shift from seston to carnivorous feeding, depending on the availability of these food resources. Measurements of gut fluorescence and grazing gave comparable ingestion rates. Rotifers displayed the highest ingestion rates (up to 486% body C d-1). Despite high total phytoplankton and seston biomasses, the high ingestion rates and selective grazing of rotifers induced auto food-limitation phenomena and caused major changes in seston abundance and size structure. Grazing impact was less important when A. panamensis dominated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sleep-Wake Cycle of Adolescents in Côte d'Ivoire: Influence of Age,Gender, Religion and Occupation

The human sleep-wake cycle is characterized by significant individual differences. Those differences in the sleep-wake cycle are partially heritable but are also influenced by environmental factors like the light/dark cycle or social habits. In this study we analyse for the first time the sleep-wake rhythm of adolescent pupils and working adolescents in a less industrialised country in West Africa near the equator. The aim of this study was to explore the sleep wake cycle in this geographical region, using Côte d'Ivoire as an example. Data collection took place between 2nd of March and 10th of June 2009. 588 adolescents (338 girls, 250 boys) between 10 and 15 years (mean?±?SD: 12.72?±?1.63) participated in this study. We collected data on the religion of the participants (Christian (N?=?159), Muslim (N?=?352), other/no religion (N?=?77)) and their occupation. Participants were either pupils attending school (N?=?336) or adolescents that were already working (N?=?252) and not attending school. The interviewer filled in the questionnaire. We found significant effects of age (p?<?0.001), gender (p?<?0.001), occupation (p?=?0.002), religion (p?<?0.001) and region (p?<?0.001). The midpoint of sleep was on average 1:26 (SD: 00:30) on weekdays and 1:37 (SD: 00:42) on weekend days. There are significant differences between weekdays and weekend days, but these were only small. Sleep duration suggests that adolescents in Côte d'Ivoire may gain sufficient sleep during week and weekend days, and thus, may live more in accordance with their own biological clock than adolescents in the northern hemisphere. In contrast, the data can be interpreted that adolescents live in a permanent ‘jetlag’. Factors may be the more continuous light/dark cycle in the tropics, low amount of ambient light and less electricity.     

Enteric protists in wild western chimpanzees (Pan troglodytes verus) and humans in Comoé National Park,Côte d'Ivoire

Primates - The western chimpanzee (Pan troglodytes verus), a subspecies of the common chimpanzee, is currently listed as Critically Endangered. Human-driven habitat loss and infectious diseases are...     

Novel arenavirus sequences in Hylomyscus sp. and Mus (Nannomys) setulosus from Côte d'Ivoire: implications for evolution of arenaviruses in Africa

This study aimed to identify new arenaviruses and gather insights in the evolution of arenaviruses in Africa. During 2003 through 2005, 1,228 small mammals representing 14 different genera were trapped in 9 villages in south, east, and middle west of C?te d'Ivoire. Specimens were screened by pan-Old World arenavirus RT-PCRs targeting S and L RNA segments as well as immunofluorescence assay. Sequences of two novel tentative species of the family Arenaviridae, Menekre and Gbagroube virus, were detected in Hylomyscus sp. and Mus (Nannomys) setulosus, respectively. Arenavirus infection of Mus (Nannomys) setulosus was also demonstrated by serological testing. Lassa virus was not found, although 60% of the captured animals were Mastomys natalensis. Complete S RNA and partial L RNA sequences of the novel viruses were recovered from the rodent specimens and subjected to phylogenetic analysis. Gbagroube virus is a closely related sister taxon of Lassa virus, while Menekre virus clusters with the Ippy/Mobala/Mopeia virus complex. Reconstruction of possible virus-host co-phylogeny scenarios suggests that, within the African continent, signatures of co-evolution might have been obliterated by multiple host-switching events.     

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.     

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.     

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.     

Telenovelas Reception by Women in Bouaké (Côte D'Ivoire) and Bamako (Mali)

In Bamako and Bouaké, women's craving for telenovelas evidences the fact that television triggers an identity dynamics in them. First of all in their external appearance, imitating clothing and hairstyle makes of these series a source of inspiration for fashion. Secondly, television, as a window to an alien world, allows them to become aware of their own social relations and to want them transformed. This is done through parent/child relationships, their conditions as spouses or spouses-to-be, and lastly, the daily exposure to love manifestations.