Disease Surveillance Networks Initiative Africa: Final Evaluation

The overall objective of the Foundation's Disease Surveillance Networks (DSN) Initiative is to strengthen technical capacity at the country level for disease surveillance and to bolster response to outbreaks through the sharing of technical information and expertise. It supports formalizing collaboration, information sharing and best practices among established networks as well as trans-national, interdisciplinary and multi-sectoral efforts, and is experienced in developing and fostering innovative partnerships. In order to more effectively address disease threats, the DSN has four key outcome areas:(1) forming and sustaining trans-boundary DSN;(2) strengthening and applying technical and communication skills by local experts and institutions;(3) increasing access and use of improved tools and methods on information sharing, reporting and monitoring; and(4) emphasizing One Health and transdisciplinary approaches to policy and practice at global, regional and local levels

Children's stress-related reports and stress biomarkers interact in their association with metabolic syndrome risk

The purpose was to examine the cross-sectional associations of stress-related reports and stress biomarkers with metabolic syndrome (MetS) risk in children while also testing the interaction between stress biomarkers and stress reports. In 353 children (5-10years old, 7.9% overweight/obese), MetS risk was measured by blood pressure, waist circumference, glucose homeostasis, triglycerides, and high-density cholesterol. Stress was measured by stress-related reports (events, emotions, and internalizing/externalizing problems) and two biomarkers: salivary cortisol (total-day and morning output) and heart rate variability (percentage of consecutive normal RR intervals differing more than 50ms and low-to-high-frequency ratio). Cross-sectional regression analyses with z scored total MetS risk as outcome were adjusted for age, sex, and socio-economic status. Only internalizing problems were directly related to a higher MetS risk score (=0.236). Cortisol and heart rate variability were significant moderators: High cortisol morning output resulted in a positive (unfavourable) report-MetS relationship (=0.259-0.552), whereas low percentage of consecutive normal RR intervals differing more than 50ms resulted in a negative (favourable) report-MetS relationship (=-0.298) and low low-to-high-frequency ratio in a positive (unfavourable) report-MetS relationship (=0.478). In conclusion, stress can sometimes be a disadvantageous factor in metabolic health of otherwise healthy children. The cortisol biomarker seems relevant because metabolic risk was highest when stress-related reports were accompanied by high morning cortisol output

FLOTAC for the diagnosis of Hymenolepis spp. infection: proof-of-concept and comparing diagnostic accuracy with other methods

Hymenolepis nana is the most common cestode parasitizing humans, yet it is under-diagnosed. We determined the optimal flotation solution (FS) for the diagnosis of this intestinal parasite with the FLOTAC method, and compared its diagnostic accuracy with an ether-concentration technique and the Kato-Katz method. Zinc sulphate (specific gravity 1.20) proved to be the best-performing FS. Using this FS, we detected 65 H. nana infections among 234 fixed fecal samples from Tajik and Sahrawi children (prevalence 27.8%). The ether-concentration technique detected 40 infections (prevalence 17.1%) in the same samples. Considering the combined results as a reference, the sensitivities of FLOTAC and ether-concentration were 95.6% and 58.8%, respectively. The Kato-Katz method resulted in a prevalence of only 8.7%. In terms of eggs per gram of stool, a significantly (P <0.05) higher value was obtained with the FLOTAC and Kato-Katz techniques compared to ether-concentration. In another study carried out in China, the FLOTAC method detected six Hymenolepis diminuta infections in 302 fecal samples, whereas five samples were found positive with the Kato-Katz technique. We conclude that FLOTAC is an accurate coprodiagnostic technique for H. nana and H. diminuta, two species which join a growing list of intestinal parasites that can be reliably diagnosed by this techniqu

History of malaria control in Tajikistan and rapid malaria appraisal in an agro-ecological setting

10.1186/1475-2875-7-217Malaria Journal721

Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snail Biomphalaria pfeifferi

Inbreeding species of hermaphroditic animals practising copulation have been characterized by few copulations, no waiting time (the time that an isolated individual waits for a partner before initiating reproduction compared with paired individuals) and limited inbreeding (self-fertilization) depression. This syndrome, which has never been fully studied before in any species, is analysed here in the highly selfing freshwater snail Biomphalaria pfeifferi. We conducted an experiment under laboratory conditions over two generations (G1 and G2) using snails sampled from two populations (100 individuals per population). G1 individuals were either isolated or paired once a week (potentially allowing for crosses), and monitored during 29 weeks for growth, fecundity and survival. Very few copulations were observed in paired snails, and there was a positive correlation in copulatory activity (e.g. number of copulations) between the male and female sexual roles. The waiting time was either null or negative, meaning that isolated individuals initiated reproduction before paired ones. G2 offspring did not differ in hatching rate and survival (to 28 days) between treatments, but offspring from paired individuals grew faster than those from isolated individuals. On the whole, the self-fertilization depression was extremely low in both populations. Another important result is that paired G1 individuals began laying (selfed) eggs several weeks prior to initiating copulation: this is the first characterization of prior selfing (selfing initiated prior to any outcrossing) in a hermaphroditic animal. A significant population effect was observed on most traits studied. Our results are discussed with regard to the maintenance of low outcrossing rates in highly inbreeding specie

Multiple parasite infections and their relationship to self-reported morbidity in a community of rural Côte d'Ivoire

Background Concomitant parasitic infections are common in the developing world, yet most studies focus on a single parasite in a narrow age group. We investigated the extent of polyparasitism and parasite associations, and related these findings to self-reported morbidity. Methods Inhabitants of 75 randomly selected households from a single village in western Côte d'Ivoire provided multiple faecal specimens and a single finger prick blood sample. The Kato-Katz technique and a formol-ether concentration method were employed to screen faecal samples for Schistosoma mansoni, soil-transmitted helminths and intestinal protozoa. Giemsa-stained blood smears were analysed for malaria parasites. A questionnaire was administered for collection of demographic information and self-reported morbidity indicators. Results Complete parasitological data were obtained for 500/561 (89.1%) participants, similarly distributed among sex, with an age range from 5 days to 91 years. The prevalences of Plasmodium falciparum, hookworms, Entamoeba histolytica/E. dispar, and S. mansoni were 76.4%, 45.0%, 42.2%, and 39.8%, respectively. Three-quarters of the population harboured three or more parasites concurrently. Multivariate analysis revealed significant associations between several pairs of parasites. Some parasitic infections and the total number of parasites were significantly associated with self-reported morbidity indicators. Conclusions Our data confirm that polyparasitism is very common in rural Côte d'Ivoire and that people have clear perceptions about the morbidity caused by some of these parasitic infections. Our findings can be used for the design and implementation of sound intervention strategies to mitigate morbidity and co-morbidit

Prevalence and risk factors of helminths and intestinal protozoa infections among children from primary schools in western Tajikistan

BACKGROUND: Intestinal parasitic infections represent a public health problem in Tajikistan, but epidemiological evidence is scarce. The present study aimed at assessing the extent of helminths and intestinal protozoa infections among children of 10 schools in four districts of Tajikistan, and to make recommendations for control. METHODS: A cross-sectional survey was carried out in early 2009. All children attending grades 2 and 3 (aged 7-11 years) from 10 randomly selected schools were invited to provide a stool sample and interviewed about sanitary situation and hygiene behaviour. A questionnaire pertaining to demographic and socioeconomic characteristics was addressed to the heads of households. On the spot, stool samples were subjected to duplicate Kato-Katz thick smear examination for helminth diagnosis. Additionally, 1-2 g of stool was fixed in sodium acetate-acetic acid formalin, transferred to a specialized laboratory in Europe and examined for helminths and intestinal protozoa. The results from both methods combined served as diagnostic 'gold' standard. RESULTS: Out of 623 registered children, 602 participated in our survey. The overall prevalence of infection with helminths and pathogenic intestinal protozoa was 32.0% and 47.1%, respectively. There was pronounced spatial heterogeneity. The most common helminth species was Hymenolepis nana (25.8%), whereas the prevalences of Ascaris lumbricoides, hookworm and Enterobius vermicularis were below 5%. The prevalence of pathogenic intestinal protozoa, namely Giardia intestinalis and Entamoeba histolytica/E. dispar was 26.4% and 25.9%, respectively. Almost half of the households draw drinking water from unimproved sources, such as irrigation canals, rivers and unprotected wells. Sanitary facilities were pit latrines, mostly private, and a few shared with neighbours. The use of public tap/standpipe as a source of drinking water emerged as a protective factor for G. intestinalis infection. Protecte spring water reduced the risk of infection with E. histolytica/E. dispar and H. nana. CONCLUSIONS: Our data obtained from the ecological 'lowland' areas in western Tajikistan call for school-based deworming (recommended drugs: albendazole and metronidazole), combined with hygiene promotion and improved sanitation. Further investigations are needed to determine whether H. nana represents a public health problem

Trends in reported malaria cases and the effects of malaria control in the Democratic Republic of the Congo

Considerable upscaling of malaria control efforts have taken place over the last 15 years in the Democratic Republic of Congo, the country with the second highest malaria case load after Nigeria. Malaria control interventions have been strengthened in line with the Millenium Development Goals. We analysed the effects of these interventions on malaria cases at health facility level, using a retrospective trend analysis of malaria cases between 2005 and 2014. Data were collected from outpatient and laboratory registers based on a sample of 175 health facilities that represents all eco-epidemiological malaria settings across the country.; We applied a time series analysis to assess trends of suspected and confirmed malaria cases, by health province and for different age groups. A linear panel regression model controlled for non-malaria outpatient cases, rain fall, nightlight intensity, health province and time fixed effects, was used to examine the relationship between the interventions and malaria case occurrences, as well as test positivity rates.; Overall, recorded suspected and confirmed malaria cases in the DRC have increased. The sharp increase in confirmed cases from 2010 coincides with the introduction of the new treatment policy and the resulting scale-up of diagnostic testing. Controlling for confounding factors, the introduction of rapid diagnostic tests (RDTs) was significantly associated with the number of tested and confirmed cases. The test positivity rate fluctuated around 40% without showing any trend.; The sharp increase in confirmed malaria cases from 2010 is unlikely to be due to a resurgence of malaria, but is clearly associated with improved diagnostic availability, mainly the introduction of RDTs. Before that, a great part of malaria cases were treated based on clinical suspicion. This finding points to a better detection of cases that potentially contributed to improved case management. Furthermore, the expansion of diagnostic testing along with the increase in confirmed cases implies that before 2010, cases were underreported, and that the accuracy of routine data to describe malaria incidence has improved

The effect of irrigated urban agriculture on malaria, schistosomiasis and soil-transmitted helminthiasis in different settings of Côte d'Ivoire

Malaria is responsible for more than one million deaths every year, mainly children under the age of five years living in sub-Saharan Africa. At least one billion people harbor one or several of the three main soil-transmitted helminths, namely Ascaris lumbricoides, hookworms and Trichuris trichiura, and about 207 million people are infected with schistosomes. An estimated 70,000 people die each year from amoebiasis, caused by Entamoeba histolytica. Giardiasis, caused by Giardia duodenalis, is responsible for 2.8 million annual infections. Poor rural and urban communities in developing countries bear the highest burden of the above-mentioned diseases. Their causes are multifactorial including lack of access to clean water, improved sanitation and health services, as well as inadequate treatment, protection and prevention. The highest rates of urbanization currently occur in the less developed regions of Africa and Asia, and it is predicted that the majority of the population will be living in small and medium urban centers in the near future. The maintenance of traditional livelihoods, including agriculture, is a typical feature in urban settings across Africa, especially in small towns where population densities and land pressure are lower than in big cities. Urban agriculture contributes to food security and livelihood opportunities for poor urban dwellers. However, the adaptation of disease vectors and intermediate hosts to urban ecosystems has been observed, which might further enhance the negative effects associated with persistent rural lifestyles. For example, the creation of malaria vector breeding sites and contact with contaminated water and soil in areas of irrigated agriculture may increase the transmission of vector-borne, water-related and soil-transmitted parasitic diseases. This PhD focused on the interface of agriculture and human health in two different urban settings of Côte d’Ivoire. The overarching goal was to contribute to a better understanding of the effects of irrigated urban agriculture on the transmission of malaria, schistosomiasis, soil-transmitted helminthiasis and intestinal protozoan infections. The research entailed a considerable amount of fieldwork, carried out between April 2004 and July 2005. In a first step, six zones of irrigated agricultural land use were identified both in Abidjan, the economic capital of Côte d’Ivoire (3.3 million inhabitants), and in the mediumsized town of Man (115,000 inhabitants) in the western part of the country. Next, two standardized mosquito breeding site assessments were conducted in these agricultural zones in the rainy season (September 2004) and in the dry season (February 2005). In each urban setting, a minimum of 120 farming households and additionally 30 non-farming households were randomly selected. Geographic coordinates of houses and the main agricultural plots were recorded. Name, age and sex of all household members were registered. In October 2004, interviews on agricultural land use, farming practices and water storage were conducted with the heads of the farming households. In a cross-sectional survey done in May/June 2005, questionnaires were administered to all households to assess the socioeconomic status, sanitary facilities and common water contact patterns. From each study participant, a finger prick blood sample and a stool sample were collected. Thick and thin blood films were stained with Giemsa and examined for Plasmodium spp. under a light microscopy. The stool samples were prepared based on the Kato-Katz technique and eggs of Schistosoma mansoni, A. lumbricoides, hookworm and T. trichiura were recorded separately. Cysts or trophozoites of intestinal protozoa, including Entamoeba histolytica/E. dispar and G. duodenalis were identified using an ether-formalin concentration method. Risk factors were identified by fitting multivariate non-random and random effects Bayesian regression models integrating spatial correlation of infection. Agricultural land use in Abidjan was characterized by market gardens on lagoon shores and high-yield vegetable production. The vegetable production areas in Abidjan developed as a consequence of land access difficulties in unexploited public and private areas near poor settlements, mainly at lagoon shores. In Man, farming was family- and subsistence-based. Predominant agricultural activities were traditional irrigated rice farming and vegetable production in lowlands and along the Kô River. The typical demographic and socio-economic profile of a vegetable producer in Abidjan is that he is an immigrant from Burkina Faso, illiterate and lacking a professional agricultural training. Malaria and intestinal parasitic infections were most prevalent among the final study cohort of 370 farmers and family members from 121 farming households. We found overall prevalences of T. trichiura, P. falciparum and hookworm of 42.6%, 24.3% and 17.3%, respectively. The parasites were heterogeneously distributed between the six market garden zones. Prior health issues were suppressed by the farmers with the daily livelihood struggle and reported symptoms due to intestinal parasitic infections were of less importance when compared to malaria. In-depth focus group discussions revealed that the working environment was discerned as unhealthy, and waste dumps and human defecation grounds were perceived as main health risks. Farmer communities and their network are indicative for the degree of social coherence and stability in a vegetable production area because these zones are characterized by highly dynamic land use patterns. In the town of Man, Anopheles larvae were present in 50.7% and 42.4% of 369 and 589 examined potential mosquito breeding sites in the rainy and in the dry season, respectively. The most productive habitats were man-made, i.e. agricultural trenches, irrigation wells, and flooded and recently transplanted rice plots. The overall prevalence of P. falciparum infections in the final study cohort of 574 individuals from 112 farming households was 32.1%. Risk factors for P. falciparum in children <15 years of age included living in specific agricultural zones (i.e. traditional irrigated rice plots, mixed crops and a large rice perimeter), proximity to permanent man-made ponds and fish ponds, periodic stays overnight in farm huts and low socio-economic status. The final study cohort for S. mansoni and soil-transmitted helminthiasis comprised 586 individuals from 113 farming households. The overall prevalences of S. mansoni, hookworm, E. histolytica/E. dispar and G. duodenalis were 51.4%, 24.7%, 20.2% and 6.3%, respectively. Members from farming households harbored significantly more often an infection with E. histolytica/E. dispar and G. duodenalis when compared to non-farming households. Predictors for an S. mansoni infection included close proximity to the Kô River, contact with irrigation wells and ponds on the agricultural plots and low educational attainment. Risk factors for hookworm infection comprised living in agricultural zones of traditional smallholder irrigated rice plots and a large rice perimeter, using water from domestic wells and low socio-economic status. Infection prevalences of P. falciparum, S. mansoni and hookworm were spatially highly heterogeneous between the agricultural zones and highest infections occurred in a zone of a large rice perimeter. P. falciparum infection intensity and hookworm infection prevalence were best explained by spatial random effect models. Spatial correlation between farmers’ houses was not significant. The findings of the present work illustrated a clear picture of the interconnections between specific irrigated agricultural land use and agricultural activities, and malaria and intestinal parasitic infections in different urban settings of Côte d’Ivoire. The outcomes lead to an enhanced understanding of their epidemiology in local agro-ecological urban settings and related contextual determinants (i.e. agricultural, behavioural, demographic, socioeconomic and environmental factors) and allows the design of readily adapted prevention and control interventions (e.g. tangible vector control strategies and prevention measures for helminth infections) which actively involve farming communities in the subsequent implementation and control management