Health & Demographic Surveillance System Profile: The Taabo Health and Demographic Surveillance System, Côte d'Ivoire.

The Taabo Health and Demographic Surveillance System (HDSS) is located in south-central Côte d'Ivoire, approximately 150 km north-west of Abidjan. The Taabo HDSS started surveillance activities in early 2009 and the man-made Lake Taabo is a key eco-epidemiological feature. Since inception, there has been a strong interest in research and integrated control of water-associated diseases such as schistosomiasis and malaria. The Taabo HDSS has generated setting-specific evidence on the impact of targeted interventions against malaria, schistosomiasis and other neglected tropical diseases. The Taabo HDSS consists of a small town, 13 villages and over 100 hamlets. At the end of 2013, a total population of 42 480 inhabitants drawn from 6707 households was under surveillance. Verbal autopsies have been conducted to determine causes of death. Repeated cross-sectional epidemiological surveys on approximately 5-7% of the population and specific, layered-on haematological, parasitological and questionnaire surveys have been conducted. The Taabo HDSS provides a database for surveys, facilitates interdisciplinary research, as well as surveillance, and provides a platform for the evaluation of health interventions. Requests to collaborate and to access data are welcome and should be addressed to the secretariat of the Centre Suisse de Recherches Scientifiques en Côte d'Ivoire: [secretariat@csrs.ci].

Prevalence and public health relevance of micronutrient deficiencies and undernutrition in pre-school children and women of reproductive age in Côte d'Ivoire, West Africa.

OBJECTIVE: To provide nationally representative data on the prevalence of anaemia, vitamin A and Fe deficiencies among pre-school age children (pre-SAC) and non-pregnant women of reproductive age (WRA), and on vitamin B12 and folate deficiencies in WRA, and the influence of inflammation on their interpretation. DESIGN: A cross-sectional survey to measure anthropometry, malaria parasitaemia and micronutrient status. Specifically, blood samples were analysed for Hb, plasma ferritin, soluble transferrin receptors, C-reactive protein, α1-acid glycoprotein, retinol-binding protein, vitamin B12 and folate. SETTING: Côte d'Ivoire in 2007. SUBJECTS: Nine hundred and twenty-eight WRA and 879 pre-SAC. RESULTS: In WRA, prevalence of Plasmodium parasitaemia (5 %) was low, but inflammation (34 %) was higher. Anaemia was a severe public health problem and prevalence differed by residency and eco-region. Inflammation-adjusted Fe deficiency was highest in urban areas (20 %). Nationally, folate deficiency was 86 %, higher in urban areas and varied by eco-region. Prevalence of vitamin B12 deficiency was low but higher in the rural areas and the north. Inflammation-adjusted vitamin A deficiency was very low (1 %). In pre-SAC, prevalence of inflammation (67 %) and Plasmodium parasites (25 %) was high; the latter was associated with poverty, rural residency and higher ferritin concentrations. Anaemia was classified as a severe public health problem (72 %), and was higher in rural areas (76 %) and the north (87 %). A quarter of pre-SAC suffered from vitamin A deficiency (inflammation-adjusted) and prevalence of undernutrition was high. CONCLUSIONS: Prevalence of inflammation, Plasmodium parasitaemia and micronutrient deficiencies were high in Côte d'Ivoire, particularly in pre-SAC. Nutritional interventions should be accompanied by strategies to reduce exposure to infections.

Comparison of a possession score and a poverty index in predicting anaemia and undernutrition in pre-school children and women of reproductive age in rural and urban Côte d'Ivoire.

OBJECTIVE: To determine whether a possession score or a poverty index best predicts undernutrition and anaemia in women of reproductive age (15-49 years; WRA) and children aged 6-59 months living in Côte d'Ivoire. DESIGN: Anthropometric measurements were converted to Z-scores to assess stunting, wasting and underweight in children, and converted to BMI in WRA. A venous blood sample was drawn, and Hb concentration and Plasmodium spp. infection were determined. A possession score was generated with categories of zero to four possessions. A five-point (quintile) poverty index using household assets was created using principal component analysis. These socio-economic measures were compared for their ability to predict anaemia and malnutrition. SETTING: Data were from a nationally representative survey conducted in Côte d'Ivoire in 2007. SUBJECTS: A sample of 768 WRA and 717 children aged 6-59 months was analysed. RESULTS: Overall, 74·9 % of children and 50·2 % of WRA were anaemic; 39·5 % of the children were stunted, 28·1 % underweight and 12·8 % wasted, while 7·4 % of WRA had BMI < 18·5 kg/m2. In general, there were more stunted and underweight children and thin WRA in rural areas. The poverty index showed a stronger relationship with nutritional status than the possession score; mean Hb difference between the poorest and wealthiest quintiles in children and WRA was 8·2 g/l and 6·5 g/l, respectively (13·9 % and 19·8 % difference in anaemia, respectively; P < 0·001), and Z-scores and BMI were significantly better in the wealthiest quintile (P < 0·001). CONCLUSIONS: The poverty index was generally a better predictor of undernutrition in WRA and pre-school children than the possession score.

Effect of an armed conflict on relative socioeconomic position of rural households: case study from western Côte d'Ivoire.

BACKGROUND: Current conceptual frameworks on the interrelationship between armed conflict and poverty are based primarily on aggregated macro-level data and/or qualitative evidence and usually focus on adherents of warring factions. In contrast, there is a paucity of quantitative studies about the socioeconomic consequences of armed conflict at the micro-level, i.e., noncommitted local households and civilians. METHODS: We conducted a secondary analysis of data pertaining to risk factors for malaria and neglected tropical diseases. Standardized questionnaires were administered to 182 households in a rural part of western Côte d'Ivoire in August 2002 and again in early 2004. Between the two surveys, the area was subject to intensive fighting in the Ivorian civil war. Principal component analysis was applied at the two time points for constructing an asset-based wealth-index and categorizing the households in wealth quintiles. Based on quintile changes, the households were labeled as 'worse-off', 'even' or 'better-off'. Statistical analysis tested for significant associations between the socioeconomic fates of households and head of household characteristics, household composition, village characteristics and self-reported events associated with the armed conflict. Most-poor/least-poor ratios and concentration indices were calculated to assess equity changes in households' asset possession. RESULTS: Of 203 households initially included in the first survey, 21 were lost to follow-up. The population in the remaining 182 households shrunk from 1,749 to 1,625 persons due to migration and natural population changes. However, only weak socioeconomic dynamics were observed; every seventh household was defined as 'worse-off' or 'better-off' despite the war-time circumstances. Analysis of other reported demographic and economic characteristics did not clearly identify more or less resilient households, and only subtle equity shifts were noted.However, the results indicate significant changes in livelihood strategies with a significant return to agricultural production and a decrease in the diversity of socioeconomic activities. CONCLUSION: Situational constraints and methodological obstacles are inherent in conflict settings and hamper conflict-related socioeconomic research. Furthermore, sensitive methods to assess and meaningfully interpret longitudinal micro-level wealth data from low-income countries are lacking. Despite compelling evidence of socioeconomic dynamics triggered by armed conflicts at the macro-level, we could not identify similar effects at the micro-level. A deeper understanding of household profiles that are more resilient to armed conflict could help to better prevent and/or alleviate adverse conflict-related and increasingly civilian-borne socioeconomic effects.

The use of insecticide-treated nets for reducing malaria morbidity among children aged 6-59 months, in an area of high malaria transmission in central Côte d'Ivoire.

BACKGROUND: Long-lasting insecticidal nets (LLINs) are an important tool for controlling malaria. Much attention has been devoted to determine both the effect of LLINs on the reduction of Plasmodium infection rate and on clinically-confirmed malaria cases in sub-Saharan Africa. We carried out an epidemiological study to investigate whether LLINs impact on Plasmodium prevalence rate and the proportion of clinically-confirmed malaria cases, in five villages in the district of Toumodi, central Côte d'Ivoire. METHODS: From April 2007 to November 2008, a community-based malaria control programme was implemented in the study villages, which involved large-scale distribution of LLINs, and training and sensitization activities within the community. We determined the effect of this programme on Plasmodium prevalence rate, clinically-confirmed malaria cases and proportion of high parasitaemia rates in children aged 6-59 months through a series of cross-sectional surveys starting in April 2007 and repeated once every 6 months. RESULTS: We observed a significant decrease in the mean P. falciparum prevalence rate from April 2007 to April 2008 (p = 0.029). An opposite trend was observed from November 2007 to November 2008 when P. falciparum prevalence rate increased significantly (p = 0.003). Highly significant decreases in the proportions of clinical malaria cases were observed between April 2007 and April 2008 (p < 0.001), and between November 2007 and November 2008 (p = 0.001). CONCLUSIONS: Large-scale distribution of LLINs, accompanied by training and sensitization activities, significantly reduced Plasmodium prevalence rates among young children in the first year of the project, whereas overall clinical malaria rates dropped over the entire 18-month project period. A decrease in community motivation to sleep under bed nets, perhaps along with changing patterns of malaria transmission, might explain the observed increase in the Plasmodium prevalence rate between November 2007 and November 2008.

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.

Dynamics of socioeconomic risk factors for neglected tropical diseases and malaria in an armed conflict.

BACKGROUND: Armed conflict and war are among the leading causes of disability and premature death, and there is a growing share of civilians killed or injured during armed conflicts. A major part of the civilian suffering stems from indirect effects or collateral impact such as changing risk profiles for infectious diseases. We focused on rural communities in the western part of Côte d'Ivoire, where fighting took place during the Ivorian civil war in 2002/2003, and assessed the dynamics of socioeconomic risk factors for neglected tropical diseases (NTDs) and malaria. METHODOLOGY: The same standardized and pre-tested questionnaires were administered to the heads of 182 randomly selected households in 25 villages in the region of Man, western Côte d'Ivoire, shortly before and after the 2002/2003 armed conflict. PRINCIPAL FINDINGS: There was no difference in crowding as measured by the number of individuals per sleeping room, but the inadequate sanitation infrastructure prior to the conflict further worsened, and the availability and use of protective measures against mosquito bites and accessibility to health care infrastructure deteriorated. Although the direct causal chain between these findings and the conflict are incomplete, partially explained by the very nature of working in conflict areas, the timing and procedures of the survey, other sources and anecdotal evidence point toward a relationship between an increased risk of suffering from NTDs and malaria and armed conflict. CONCLUSION: New research is needed to deepen our understanding of the often diffuse and neglected indirect effects of armed conflict and war, which may be worse than the more obvious, direct effects.

Sequential analysis of helminth egg output in human stool samples following albendazole and praziquantel administration.

Large-scale administration of anthelminthic drugs currently is the most widely used intervention for controlling morbidity due to schistosomiasis and soil-transmitted helminthiasis. An important issue is drug efficacy monitoring. However, the optimal time points post-treatment for assessing the efficacy of praziquantel against Schistosoma mansoni and albendazole against hookworm infections are not known. Forty-nine schoolchildren infected with S. mansoni and 52 infected with hookworm were treated with a single oral dose of praziquantel (40 mg/kg) and albendazole (400 mg), respectively. Stool samples were collected on 19 occasions over a 44-day post-treatment follow-up period, and two Kato-Katz thick smears per sample were examined at each time point. Both the mean egg counts and observed cure rates varied depending on the time point post-treatment. The highest reduction in the geometric mean egg counts (>97%) and the highest observed cure rate (>97%) of S. mansoni infections were found 15-20 days after praziquantel administration. Among the hookworm-infected children, egg counts decreased rapidly within the first week after albendazole administration (>95%), whereas infection rates showed high and heterogeneous (45.0-71.2%) levels at later time points. Both praziquantel and albendazole were highly efficacious in reducing the overall egg burden of S. mansoni and hookworm, respectively. We suggest that 15-20 days post-treatment is the most appropriate time point for efficacy evaluation of praziquantel against S. mansoni. Although no clear conclusion can be drawn for the optimal timing of efficacy evaluation of albendazole against hookworm, a 2-3-week time frame seems a reasonable compromise. This is justified on logistical grounds (i.e. collection of stool samples only once) and growing emphasis on integrating the control of schistosomiasis and soil-transmitted helminthiasis, including drug efficacy monitoring.

Social and cultural aspects of 'malaria' and its control in central Côte d'Ivoire.

BACKGROUND: A sound local understanding of preventive measures and health-seeking behaviour is important for the effective control of malaria. The purpose of this study was to assess the knowledge, attitudes, practices and beliefs of 'malaria' and its control in two rural communities of central Côte d'Ivoire, and to examine associations between 'malaria' and the households' socioeconomic status. METHODS: A cross-sectional household survey was carried out, using a combination of qualitative and quantitative methods. People's socioeconomic status was estimated, employing a household asset-based approach. RESULTS: Malaria was identified as djèkouadjo, the local folk name of the disease. Although people were aware of malaria-related symptoms and their association with mosquitoes, folk perceptions were common. In terms of treatment, a wide array of modern and traditional remedies was employed, often in combination. Individuals with a sound knowledge of the causes and symptoms of malaria continued to use traditional treatments and only a few people sleep under bed nets, whereas folk beliefs did not necessarily translate into refusal of modern treatments. Perceived causes of malaria were linked to the household's socioeconomic status with wealthier individuals reporting mosquitoes more frequently than poorer households. Bed nets were more frequently used in wealthier social strata, whereas other protective measures--perceived to be cheaper--were more prominent among the poorest. CONCLUSION: Equitable access to resources at household, community and health system levels are essential in order to enable community members to prevent and treat malaria. There is a need for community-based approaches that match health care services with poor people's needs and resources.

FLOTAC: a new sensitive technique for the diagnosis of hookworm infections in humans.

Hookworms infect more than 10% of the world's population, but current diagnostic tools have drawbacks. Our objective was to compare the diagnostic performance of three methods (Kato-Katz, ether concentration and FLOTAC techniques) for hookworm diagnosis. Stool samples were obtained from 102 schoolchildren in Côte d'Ivoire. First, a duplicate 41.7mg Kato-Katz thick smear was prepared. Next, a small portion of stool (mean weight 1.8g) was preserved in sodium acetate-acetic acid-formalin and forwarded to a European laboratory. These samples were split in three parts, one processed by an ether concentration technique and two by the FLOTAC technique. All samples were examined by experienced technicians for hookworm eggs using light microscopy. The observed hookworm prevalences as assessed by the FLOTAC, Kato-Katz and ether concentration techniques were 65.7%, 51.0% and 28.4%, respectively. Considering the combined results as the diagnostic 'gold' standard, the FLOTAC technique had a sensitivity of 88.2% compared with 68.4% for the Kato-Katz and 38.2% for the ether concentration techniques. The Kato-Katz method resulted in a significantly higher mean number of eggs per gram of stool (155.8 EPG) compared with the FLOTAC (37.7 EPG) and ether concentration (5.7 EPG) methods. The FLOTAC method shows promise as an important new tool for individual hookworm diagnosis and for rigorous monitoring of helminth control programmes. [Clinical Trial No. ISRCTN21782274].

Risk factors for Schistosoma mansoni and hookworm in urban farming communities in western Côte d'Ivoire.

OBJECTIVES: To identify risk factors for Schistosoma mansoni and hookworm infections in urban farming communities, and to investigate small-scale spatial patterns of infection prevalence. METHODS: A cross-sectional survey was carried out in 113 farming households (586 individuals) and 21 non-farming households (130 individuals) from six agricultural zones in the town of Man, western Côte d'Ivoire. Heads of households were interviewed on common agricultural activities, land and water use, education attainment, socioeconomic status and sanitation facilities. Household members provided stool specimens that were processed by the Kato-Katz technique and a formol-ether concentration method and diagnosed for S. mansoni, hookworms and other soil-transmitted helminths and intestinal protozoa. Bayesian statistics were employed for spatial analyses. RESULTS: The prevalences of S. mansoni and hookworm in farming households were 51.4% and 24.7%, respectively. Risk factors for a S. mansoni infection comprised living in close proximity to the Kô River, water contact with irrigation wells and ponds and low education attainment. Living in zones of smallholder irrigated rice plots or large rice perimeters, using water from domestic wells, and low socioeconomic status were risk factors for a hookworm infection. We found significant spatial heterogeneity between agricultural zones, with the highest infection prevalences of S. mansoni and hookworm in the zone where there was a large rice perimeter. CONCLUSIONS: In this urban setting, both S. mansoni and hookworm infections were related to specific agricultural activities. Health education and active participation of urban farmers for the control of schistosomiasis and soil-transmitted helminthiasis is recommended.

Urban farming and malaria risk factors in a medium-sized town in Cote d'Ivoire.

Urbanization occurs at a rapid pace across Africa and Asia and affects people's health and well-being. A typical feature in urban settings of Africa is the maintenance of traditional livelihoods, including agriculture. The purpose of this study was to investigate malaria risk factors in urban farming communities in a medium-sized town in Côte d'Ivoire. Two cross-sectional surveys were carried out among 112 households from six agricultural zones. First, the heads of households were interviewed on agricultural land use, farming practices, water storage, sanitation facilities, and socioeconomic status. Second, a finger prick blood sample was taken from all household members and examined for the occurrence and density of Plasmodia. Geographic coordinates of houses, farming plots, and potential mosquito breeding sites were recorded and integrated into a geographic information system. Predictors of Plasmodium falciparum parasitemia were assessed using non-random and random effects Bayesian regression models. The overall prevalence of P. falciparum was 32.1%. In children < 15 years of age, risk factors for a P. falciparum infection included living in a specific agricultural zone, close proximity to permanent ponds and fish ponds, periodic stays overnight in temporary farm huts, and low socioeconomic status. Our findings indicate that specific crop systems and specific agricultural practices may increase the risk of malaria in urban settings of tropical Africa.

Urban agricultural land use and characterization of mosquito larval habitats in a medium-sized town of Côte d'Ivoire.

Urban agriculture is common across Africa and contributes to the livelihoods of urban dwellers. Some crop systems create suitable mosquito breeding sites and thus might affect malaria transmission. The purpose of this study was to identify, map, and characterize potential mosquito breeding sites in agricultural land use zones in a medium-sized town of western Côte d'Ivoire and to assess risk factors for productive Anopheles breeding sites. Two surveys were carried out; one toward the end of the rainy season and the second one during the dry season. In all identified potential mosquito breeding sites, two experienced entomologists searched for the presence of Anopheles larvae and pupae with a standardized technique. Totals of 369 and 589 sites were found in the rainy and dry seasons, respectively, mainly in vegetable gardens and irrigated rice fields. Anopheles larvae were present in 50.7% and 42.4% of the sites investigated during the rainy and dry seasons, respectively. Typical Anopheles larval habitats were characterized by the presence of algae, the absence of floating vegetation, and the co-occurrence of Culex larvae. The highest Anopheles larval productivity was observed in rice paddies, agricultural trenches between vegetable patches, and irrigation wells. An indirect link could be established between the occurrence of productive Anopheles breeding sites and agricultural land use through specific man-made habitats, in particular agricultural trenches, irrigation wells, and rice paddies. Our findings have important bearings for the epidemiology and control of urban malaria in sub-Saharan Africa.