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In urban areas, networks and life-support systems, such as roads, power lines and drinking water pipes, are key infrastructures which contribute to the functioning of the city. Their damaging or destruction can lead to harmful consequences for the population. Such situation has already occurred in several African cities following the impact of a hazard of natural or human-induced origin. Bujumbura, the economic capital of Burundi, is no exception to such scenario, particularly as a result of geo-hydrological hazards which regularly affect various neighborhoods of the city: floods, flash-floods, river bank collapse, large urban gullies. For instance, the February 2014 flash flood damaged several key infrastructures in the north of Bujumbura, including the National Road number 1, a medium-voltage line and drinking water pipes.The goal of this study is to show how, in an urban system like the city of Bujumbura, the vulnerability of these key infrastructures to geo-hydrological hazards can lead to the fragility of a large territory. This vulnerability is influenced by weaknesses related to their wear or age, their construction technique, and their dependence on external systems for their effective functioning. In addition to their own weaknesses, these key infrastructures are exposed to several natural hazards that can lead to their damage or destruction. In Bujumbura, the geo-hydrological hazards that regularly impact the city are accentuated by the lack or outdated rainwater drainage facilities and the inadequacy of the urban development plan.After listing, locating and characterizing all the infrastructures that play a role in the life of the population in the urban environment, a classification, based on a participatory approach, was developed to select those on which the vulnerability assessment focused. Six forms of vulnerability (intrinsic, dependency, hazard exposure, control capacity, alternative operation, and crisis management) were assessed for each key infrastructure. To assess each form of vulnerability, interviews were conducted with facility managers (28) to supplement the data from the literature and field collection. Geometric weighting was performed to highlight the most vulnerable infrastructure that could disrupt the functioning of others and, by extension, that of the city.The results of this study show that several road sections in the center and at the exit points of Bujumbura, as well as the drinking water treatment plant and the pumping stations, stand out among the most vulnerable infrastructures. Continued efforts are required to maintain, protect, and strengthen these networks and life-support systems in the face of geo-hydrological hazards, as their damage or destruction due to cascading effects caused by dependence on, or wear and tear of, infrastructure can affect a much wider area than just the hazard impact zone.

The article analyses the livelihood of peasant farmers in the rural area of three parishes in the Paute basin in Ecuador. First, the article presents the gathered empirical data of the study sites, respectively the Pichacay in the Santa Ana parish, Caldera in the Javier Loyola parish, and Llavircay in the Rivera parish. Applying the Chayanovian and van der Ploeg interpretation frames, three types of peasant households could be distinguished, based upon their specific organizational forms of producing and reproducing their livelihoods. The article concludes that a more in-depth analysis is needed in the peasant’s art of farming, particularly in their core balance of being conditioned by and linked to as well as resistant to the capitalist economy.

The authors developed and used a game ( Tigo-Tigo) to collect data on people’s emotional experience in their environment in an area hit by a typhoon (Philippines). With the aim of encouraging the use of games for data collection in the field, they provide an in-depth analysis of all phases of the process, from the game development to the experience of the game sessions and the quality of the data produced. Designing a data collection game is creating an immersive experience that get people to share information with the researcher. However challenging to develop as it has to meet both data gathering and game requirements, Tigo-Tigo successfully produced complex data and a positive experience. By following its simple rules, the respondents were led to formulate and share both quantitative (emotion levels) and qualitative (explanations for emotion-environment associations) data. Moreover, the game was motivating and changed the status of participation, as the researchers played with the respondents in an inversed power setting. Finally, its particular interactional structure also improved the quality of the data produced by reducing expectation as well as cultural and translation barriers encountered in the field.

Disasters related to hydrological hazards are frequent, occur worldwide, and regularly devastate many African cities. The victims are commonly among the population in precarious situations, without solid infrastructure and with incomes too low to recover from disasters.Located in the western branch of the East African Rift, and squeezed between the shore of Lake Tanganyika and steep hillslopes, the city of Bujumbura hosts approximately 800,000 people. It is regularly affected by disasters related to lake and river floods, flash floods, riverbank collapses, and gullies. This research aims to assess people's vulnerability to these hydrological processes through the analysis of the territorial vulnerability of the city. To achieve this objective, we present here the first step which focuses on the evaluation of the exposure to past hydrological disasters.We built a comprehensive dataset using information from different sources, such the Civil Protection, that we combined and complemented with field data collection obtained from qualitative and quantitative surveys. Given the limited information on the susceptibility to the various processes studied, the distribution of past disasters is used as an indicator of the exposure of different parts of the city to hydrological hazards. This phenomenological approach is a key step to map and understand risk due to hydrological hazards.Between 1990 and 2021, the city recorded more than 210 catastrophic events. Flooding was the most frequent hazard. For example, with a rise of more than 2m above its normal level, the Lake Tanganyika flooding in April 2021 has induced the displacement of many people and the abandonment of many houses and recreation centers. Flash flooding and gullying have been reported mostly at the foot of the hillslopes. The collapse of river banks has also caused severe damages to infrastructures, along the major rivers crossing the city.Like many African cities, Bujumbura is characterized by the non-compliance with the law, an inefficient drainage system, the anthropization of the hillslopes overlooking the city, the increasing demand for housing and a lack of structure in its urban expansion. The older neighborhoods of central Bujumbura seem adapted to cope with these types of events, while the peri-urban areas are not. The combination of these vulnerability factors makes Bujumbura more exposed to disasters of hydrological origin.

Les principaux impacts des modifications environnementales sur les facteurs démographiques sont analysés sur la base des rapports du GIEC, la source principale des connaissances scientifiques concernant le changement climatique. La complexité des mécanismes étudiés est mise en évidence. Sont ensuite abordés les impacts du changement climatique sur les variables démographiques. Le cas des populations dites piégées est approfondi.

This chapter highlights the contribution of qualitative methods for understanding the population–environment nexus. A brief overview is offered of a variety of qualitative methods: in-depth interview, focus groups, participant observation, ethnography, and drawing. Then, the chapter presents three concrete examples of population–environment research aimed at illustrating the selection and application of appropriate tools to build qualitative knowledge. These research examples engage various time periods and diverse settings, and they combine to illustrate core dimensions of qualitative investigation including diverse methodologies such as interviews, participatory mapping, participant observation, and observant participation, photo-language, and the use of a game. The first example addresses the intersection between scientific and local knowledge, the second explores individuals’ experiences within their environment, and the third illustrates the participatory action research process. Within the description of each example, the decision-making processes around data collection and analysis are detailed. In each case, the process of interpretation is also described.

In the prolific literature on the impact of environment on migration, direct and indirect effects are often mentioned but rarely estimated separately. We use structural equation modelling to estimate how the drivers of migration (socio-economic, environmental and individual) interact with each other and jointly contribute to individuals’ migration decision in rural Burkina Faso (1970–1998). Facing a worsening environmental situation, people’s direct response tends to be short-term migrations to rural and urban areas, but the indirect effect differs: poor rainfall conditions push down socio-economic situation in communities, which in turn discourages migration to rural areas or to abroad. In total, an adverse environmental situation tends to increase the likelihood of short-term migrations to rural and urban areas and to decrease that of long-term migrations to rural areas and to abroad. These findings contribute to a clearer understanding of the migration response to poor environmental conditions.

Largely dependent on rain-fed agriculture, the West African populations could be severely impacted by climate change and variability. In this paper, we performed a literature review relating to perceptions of climate change and variability in West Africa, followed by an in-depth comparison between perceptions by rural dwellers of Burkina Faso and trends in meteorological data to discuss the importance of perceptions vis-à-vis climate trends in migration decision. Results showed that respondents perceived increasing temperature and worsening rainfall conditions over 1988–2007 matching with findings of previous studies but inconsistent with the trends observed in rainfall data. Given that climate change is recognized as a key driver of mobility on the one hand and the fact that climate change perceptions influence decision to migrate on the other hand, our results suggest to jointly include perceptions and climate data in future research on environmental migration in order to improve the understanding of household’s decision in response to climate change.

As global warming and climate change predictions become increasingly certain, there is mounting pressure to gain a better understanding of disaster risk. Climate change is seen as a major contributing factor in the recent increases in the losses and damages attributed to hazard extremes. Vulnerability is one of the key components of risk. Yet identifying who the vulnerable segments of the population are, and to which specific hazards different groups are vulnerable, remains a challenge. Measuring social vulnerability has become an active area of research, with scholars attempting to capture the differential vulnerabilities of the population exposed to certain hazards. To address these research challenges, we developed in this study social vulnerability indices at the most basic level of governance in the Philippines using raw, individual-level census data for the entire country. Our goal in conducting this research is to establish relationships between the derived vulnerability measurements and flood exposure and the impacts of coastal flash floods triggered by Tropical Storm Washi in the southern Philippines in December 2011. We find that exposure rather than vulnerability appears to play a greater role in the magnitude of the losses and damages resulting from this particular type of hazard at the localized scale. ∗ J. Andres F. Ignacio (corresponding author), Environmental Science for Social Change, 1/F Manila Observatory Bldg., Ateneo de Manila University Katipunan Road, Loyola Heights 1108 Quezon City, Philippines Email: andresignacio@essc.org.ph Grace T. Cruz, Population Institute, University of the Philippines, Quezon City, Philippines Fernando Nardi, Universita per Stranieri di Perugia, Italy Sabine Henry, Department of Geography, University of Namur, Belgium DOI: 10.1553/populationyearbook2015s091 92 Assessing the effectiveness of a social vulnerability index

International audience; Epidemiology of diphtheria in the southwestern Indian Ocean is poorly documented. We analyzed 14 cases of infection with toxigenic Corynebacterium diphtheriae reported during 2007–2015 in Mayotte, a French department located in this region. Local control of diphtheria is needed to minimize the risk for importation of the bacterium into disease-free areas.

Movement of groups of people is closely linked to environmental, agricultural and cultural change. Gaining an understanding of these changes in a local context is a vital prelude to the construction of a viable predictive model. We carried out a study in the Philippines to better understand the association between migration and these types of changes at a village scale and to build a picture of how the associations changed in time and space. The study area was located in the uplands of Mindanao. Migration to the village began in the late 1970s. As of 2010, the population is made up of indigenous people (~57 %), people who migrated from elsewhere in the Philippines (~29 %), and descendants of indigenous/non indigenous parents (~14 %). Face-to-face interviews in the village and in the places of origin/destination were used to collect qualitative information on the migrations made by the current and past village inhabitants. The main results relate to the reasons for migration, the socio-environmental processes that induced the decision to move and the description and explanation of more recent moves. The local findings are discussed in the context of existing published models of migration in frontier areas.

Despite the proximity of the Sahara, very few studies about dust impact on air quality and human health have been conducted in West Africa. The lack of data is a major constraint on our understanding of the impacts on human health in this area. We analyzed PM10 concentrations and horizontal visibility recorded in four West African stations. The pollution levels often exceed the standards defined by many countries/regulatory authorities and have been associated with serious health risks outside Africa. Over the Sahelian stations, 45.6% of the days between November 2006 and March 2007 were likely to impact human health and the studied Sudanian population was exposed to potential health effects every 5 days.

In summary, findings from the four papers in this volume demonstrate the critical role played by migration in establishing linkages between rural origins and urban destinations, and the multifaceted impacts of these linkages on individuals, families and communities in Asian developing countries. These findings are relevant to the longstanding concern about the potential adverse impacts of internal migration, the siphoning of skill and human resources to the city. While migrants themselves are generally better off by moving from rural areas to the cities, it is well known that the migration process tends to be selective of the younger, better educated, and more dynamic members of origin communities, and is therefore detrimental to the vitality of rural communities and the family members left behind. The implications of the findings presented in this volume is that while these negative effects of migrant selection do exist, they are at least partly offset by benefits derived from the linkages between rural and urban areas established in the migration process. Indeed, such connections take a variety of forms and almost certainly bring positive effects to migrant families and communities in places of origin, especially if they are maintained and properly managed. This in turn underlines the need for a clear and nuanced understanding of the way that rural-urban linkages are forged in the migration process, and the diverse forms they take.

High desert dust concentrations raise concerns about adverse health effects on human populations. Based on a systematic literature review, this paper aims to learn more about the relationship between desert dust and human health in the world and to analyse the place of West Africa as a study area of interest. Papers focussing on the potential relationship between dust and health and showing quantitative analyses, published between January 1999 and September 2011, were identified using the ISI Web of Knowledge database (N = 50). A number of adverse health effects, including respiratory, cardiovascular and cardiopulmonary diseases, are associated with dust. This survey highlights obvious dust impacts on human health independently of the study area, health outcomes and method. Moreover, it reveals an imbalance between the areas most exposed to dust and the areas most studied in terms of health effects. None of these studies has been conducted in West Africa, despite the proximity of the Sahara, which produces about half of the yearly global mineral dust. In view of the alarming results in many parts of the world (Asia, Europe, America), this paper concludes by stressing the importance of carrying out impact studies of Saharan dust in West Africa, where dust events are more frequent and intense than anywhere else.

This paper combines participatory activities (PA) with remote sensing analysis into an integrated methodology to describe and explain land-cover changes. A remote watershed on Mindanao (Philippines) is used to showcase the approach, which hypothesizes that the accuracy of expert knowledge gained from remote sensing techniques can be further enhanced by inputs from vernacular knowledge when attempting to understand complex land mosaics and past land-use changes. Six participatory sessions based on focus-group discussions were conducted. These were enhanced by community-based land-use mapping, resulting in a final total of 21 participatory land-use maps (PLUMs) co-produced by a sample of stakeholders with different sociocultural and ecological perspectives. In parallel, seven satellite images (Landsat MSS, Landsat TM, Landsat ETM+, and SPOT4) were classified following standard techniques and provided snapshots for the years 1976, 1996, and 2010. Local knowledge and collective memory contributed to define and qualify relevant land-use classes. This also provided information about what had caused the land-use changes in the past. Results show that combining PA with remote-sensing analysis provides a unique understanding of land-cover change because the two methods complement and validate one another. Substantive qualitative information regarding the chronology of land-cover change was obtained in a short amount of time across an area poorly covered by scientific literature. The remote sensing techniques contributed to test and to quantify verbal reports of land-use and land-cover change by stakeholders. We conclude that the method is particularly relevant to data-poor areas or conflict zones where rapid reconnaissance work is the only available option. It provides a preliminary but accurate baseline for capturing land changes and for reporting their causes and consequences. A discussion of the main challenges encountered (i.e. how to combine different systems of knowledge), and options for further methodological improvements, are also provided.

Using event history analyses, we investigate the impact of rainfall conditions - a crucial environmental factor in the livelihood of Sahelian households - on the risk of the first village departure in Burkina Faso. The distinction of migrations by destination and duration proves critical in studying this relationship. Findings suggest that people from the drier regions are more likely than those from wetter areas to engage in both temporary and permanent migrations to other rural areas. Also, short-term rainfall deficits tend to increase the risk of long-term migration to rural areas and decrease the risk of short-term moves to distant destinations.

This study tests the influence of environmental changes on migration in Burkina Faso. It describes individual migratory pathways in the 1960-1999 period in Burkina Faso, using environmental typologies of origins and destinations based on rainfall variations and land degradation. The study links data from a national longitudinal (retrospective) survey with fine resolution rainfall data and land degradation data. Results suggest that environmental factors influence, but in different ways, both the probability to out-migrate and the selection of a destination once the migration decision has been made. Migration seems to be more influenced by a slow-acting process such as land degradation than by episodic events such as droughts.

This study analyses the factors that cause inter-provincial migrations in an African context (Burkina Faso, West Africa), focusing specifically on the role of environmental factors in driving large migration flows in ecologically marginal regions. It uses statistical methods for modelling migration data to assess the relative importance of socio-demographic and biophysical variables. The former included the percentage of the population who are male, literacy and economic activity rates, and the presence of a resettlement policy. The latter included measures of land degradation, land availability and climatic variability, which vary considerably between different regions of the country. The results demonstrate that, as expected, demographic and socio-economic characteristics of Provinces were associated with migration patterns, and that environmental variables were also significant. However, the contribution of environmental variables in the explanation of migration was slightly lower than for the socio-demographic variables. The results show that inter-provincial migrations in Burkina Faso are influenced by high literacy and economic activity rates at the origin and destination, a high proportion of men at the origin, a low proportion of men at the destination, as well as by unfavourable conditions concerning rainfall variability, land degradation and land availability at the origin, and favourable conditions at the destination for these variables.

Growing interest in the environmental aspects of migration is not matched by research on their interrelationships, due partly to the lack of adequate data sets on the two together. Focusing on the microlevel, we describe the data required to effectively investigate these interrelationships. Data sources are discussed, including information that should be collected, focusing on household surveys and remote sensing. The main section of the paper describes three alternative approaches to data collection: (a) using existing population and environmental data from different sources, illustrated by Burkina Faso; (b) adding questions to a survey developed for another purpose, illustrated for Guatemala using a DHS survey; and (c) designing a new survey specifically to collect both migration and environmental data to investigate interrelationships, illustrated by Ecuador. Methods used and summary findings are described, followed by a discussion of their advantages and limitations. We conclude with recommendations as to effective use of each approach as research on migration-environment linkages moves forward.

Technology adoption in agriculture is one of the key factors of change in rural areas of developing countries. Large-scale in-migration by groups using a more advanced production technology often triggers such change in autochthone populations. We analyse the determinants of adoption of new agricultural technology by nomadic pastoralists using unique micro-level data from a historical episode of massive Russian peasant in-migration into Kazakhstan at the turn of the 20th century. We find that distance to Russian settlers is a key determinant of technology adoption, even after controlling for socio-economic and environmental characteristics. This effect is stronger for wealthier and less mobile Kazakh families with pasture land more suitable for agriculture. The adoption of new technology follows a heterogeneous pattern within the autochthone population, with important implications for the evolution of inequality.

Recently, the World Health Organization's International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM10), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM10 concentration of 1017 μg m-3, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.

Despite the fact that most adult humans worldwide are latently infected by the Epstein-Barr virus (EBV), only a very small percentage of them will develop an EBV-associated malignancy. We do not know whether this situation reflects the existence of more sensitive individuals or of particularly tumorigenic EBV strains. We postulated that if highly tumorigenic EBV strains did exist, they would be preferentially found in consistently EBV-associated tumors, such as nasopharyngeal carcinoma (NPC), and differ significantly from the strains present in other, non-pathological sites of the same patients. To test this hypothesis, we compared the BNLF1 gene of the EBV strains present in tumors and in "reservoir lymphocytes" of 6 NPC-bearing patients from Tunisia. Our results show that all of these patients were infected by more than 1 (and up to 7) EBV strains. Moreover, lymphocytes and tumor cells from the same individual were systematically infected by different viral strains. The origin and biological significance of these multistrain infections are discussed.

Over the last 40 years, the Sahel has seen a long-term downward trend in rainfall. The importance of ecological variables as factors affecting child survival in rural subsistence societies has already been emphasized, but little empirical evidence has been gathered to support this. This paper presents a comparative event history analysis aimed at understanding how rainfall variations may influence child mortality in two neighbouring countries, Burkina Faso and Mali. These countries are similar in terms of population dynamics, economy, livelihood, child mortality and rainfall conditions (i.e. strong south-north decreasing rainfall gradient). Individual data for both countries came from two detailed nationally representative retrospective surveys conducted in 2000. Rainfall data for the 1960-1998 time period were obtained from the Climatic Research Unit. This study shows that child survival in each country is related to specific patterns of rainfall variation across livelihood regions, highlighting the complex nature of environmental causality of child mortality.

This study aims to compare, on the one hand, the geographical distribution of the desert dust source areas, their contribution to quantities emitted into the atmosphere, the trajectories and the quantities deposited, with on the other hand the areas of research interest focused on the desert dust impacts on air quality and/or human health. Based on a systematic review of the literature using the ISI Web of Knowledge database, we found 231 articles published over the last decade on the desert dust impacts on air quality. Of these, 48% concerned Asian dust and 39% Saharan dust, with the remaining 13% divided between the other dust source areas. However, only one of these studies addressed the worsening air pollution in West Africa, even though it is very close to the Sahara, the greatest contributor to the global dust budget. Moreover, there have been very few studies (41) looking at the direct links between desert dust and human health; in this context too, no interest has been shown in West Africa. Yet this region is also among the areas in which morbidity rates have been noted to be far higher than those found in other regions of the world, and where respiratory infections alone account for more than 20% of the causes of infant mortality. This survey highlights a clear imbalance between those areas most exposed to dust and the most studied areas in terms of dust impacts. Given these findings and the often alarming results published about other regions of the world, we advocate a revival of interest in research on West Africa in order to achieve a better understanding of the desert dust impacts on air quality and health among the populations of this region.

This paper reviews and synthesizes findings from scholarly work on linkages among rural household demographics, livelihoods and the environment. Using the livelihood approach as an organizing framework, we examine evidence on the multiple pathways linking environmental variables and the following demographic variables: fertility, migration, morbidity and mortality, and lifecycles. Although the review draws on studies from the entire developing world, we find the majority of microlevel studies have been conducted in either marginal (mountainous or arid) or frontier environments, especially Amazonia. Though the linkages are mediated by many complex and often context-specific factors, there is strong evidence that dependence on natural resources intensifies when households lose human and social capital through adult morbidity and mortality, and qualified evidence for the influence of environmental factors on household decision-making regarding fertility and migration. Two decades of research on lifecycles and land cover change at the farm level have yielded a number of insights about how households make use of different land-use and natural resource management strategies at different stages. A thread running throughout the review is the importance of managing risk through livelihood diversification, ensuring future income security, and culture-specific norms regarding appropriate and desirable activities and demographic responses. Recommendations for future research are provided.

France has developed a national plan for the prevention and control of an influenza pandemic with the aim of reducing its health impact and its consequences on the economic and social life of the country. The main objectives of the plan are to prepare the country to face an epizootic of avian influenza due to a highly pathogenic virus, to detect the first manifestation of a new flu virus, to curb its spread by adopting early and appropriate public health measures and to protect the French population, as well as French citizens abroad. Ensuring that the population has the best possible access to prevention and care, through the organisation and adaptation of the health system facing a pandemic, is one of the major goals of the plan. The plan, and organisation associated to it, forms the foundation of a coherent and adaptable system which every citizen should feel ownership of.

Chapitre des actes du 13e Colloque international de Budapest, 20-24 septembre 2004

Using EBV BNLF1 gene polymorphism, we have recently shown that, in NPC bearing patients, lymphocytes and tumor cells of the same individual were infected by different viruses. It appeared as a rule that EBV infection was by multiple strains in these immunocompetent, HIV negative patients. Our data did not detect any evident association between tumor cells and a particular BNLF1 variant. In the present paper, we extend our analysis to the BZLF1 gene of the viruses present in different sites of the same patients. Only two main variants of the BZLF1 gene were identified. Despite this very weak polymorphism of this locus, our results entirely confirm the very frequent occurrence of multistrain infections in these patients, and the presence of different EBV strains in tumor cells and lymphocytes from the same individual. However, in contrast to our results concerning the BNLF1 gene, the BZLF1 variants appeared to be cell type specific, one being associated mainly with epithelial or tumor cells and the other with lymphocytes. The possible reasons for this distribution are discussed.

Background The aim of this pilot study was to evaluate the efficacy and the safety of lamivudine therapy in hepatitis B virus (HBV)-positive/DNA-positive renal transplant recipients. Methods Six HBV DNA-positive cadaveric renal transplant recipients ranging in age from 49+/-6 years were administered lamivudine, at 100 mg/day for a period of at least 6 months, on a compassionate-use basis. Lamivudine is the (-) enantiomer of 3'-thiacytidine, which is known to be a potent inhibitor of HBV replication. All of the patients but one were on cyclosporine-based immunosuppression. Results The mean serum creatinine was 134+/-44 micromol/L. The mean duration of HBV infection was 230+/-54 months (156-288). All of the patients but one had high serum alanine aminotransferase levels (122+/-52 IU/L; range, 45-243). Histological evaluation showed the presence of either chronic active hepatitis (n=4) or cirrhosis (n=2). All of the patients but one were hepatitis B e antigen negative/hepatitis B e antibody positive, but none were coinfected with either hepatitis C virus or hepatitis D virus. Conclusions Lamivudine therapy was associated with (i) a normalization of alanine aminotransferase levels in four of five patients when these levels were increased at the beginning (n=5); (ii) a rapid disappearance of HBV DNA from the serum (detected by hybridization) in all of the patients; (iii) the negativity of HBV DNA by polymerase chain reaction in four patients; and (iv) no change in renal function and in proteinuria when present (one patient). Finally, no adverse effects were noted. When lamivudine therapy was stopped for four patients after 6 months, it was associated with a biochemical and virological relapse within the weeks that followed. Lamivudine therapy was therefore resumed for these patients.

Apart from the classical determinants of child survival, ecological factors can have a strong influence on child survival in rural subsistence societies, particularly by their impact on malnutrition and on the reduction of income. Persistence of unfavourable climatic conditions may lead to a sharp reduction of food production, and children under five are particularly sensitive to food shortage. This study combines exceptionally reliable multi-source data in event-history models, to understand how rainfall variations may influence child survival in Burkina Faso, which experiences high levels of child mortality and high rainfall disparities. The results highlight the necessity of measuring the rainfall variations with accuracy at fine spatial and temporal resolutions. Child survival in Burkina Faso depends on rainfall conditions, but there are specific patterns of rainfall variations and children's mortality relationships in each agro-climatic region. Copyright © 2007 John Wiley & Sons, Ltd.

The causative agents of leptospirosis are responsible for an emerging zoonotic disease worldwide. One of the major routes of transmission for leptospirosis is the natural environment contaminated with the urine of a wide range of reservoir animals. Soils and surface waters also host a high diversity of non-pathogenic Leptospira and species for which the virulence status is not clearly established. The genus Leptospira is currently divided into 35 species classified into three phylogenetic clusters, which supposedly correlate with the virulence of the bacteria. In this study, a total of 90 Leptospira strains isolated from different environments worldwide including Japan, Malaysia, New Caledonia, Algeria, mainland France, and the island of Mayotte in the Indian Ocean were sequenced. A comparison of average nucleotide identity (ANI) values of genomes of the 90 isolates and representative genomes of known species revealed 30 new Leptospira species. These data also supported the existence of two clades and 4 subclades. To avoid classification that strongly implies assumption on the virulence status of the lineages, we called them P1, P2, S1, S2. One of these subclades has not yet been described and is composed of Leptospira idonii and 4 novel species that are phylogenetically related to the saprophytes. We then investigated genome diversity and evolutionary relationships among members of the genus Leptospira by studying the pangenome and core gene sets. Our data enable the identification of genome features, genes and domains that are important for each subclade, thereby laying the foundation for refining the classification of this complex bacterial genus. We also shed light on atypical genomic features of a group of species that includes the species often associated with human infection, suggesting a specific and ongoing evolution of this group of species that will require more attention. In conclusion, we have uncovered a massive species diversity and revealed a novel subclade in environmental samples collected worldwide and we have redefined the classification of species in the genus. The implication of several new potentially infectious Leptospira species for human and animal health remains to be determined but our data also provide new insights into the emergence of virulence in the pathogenic species., Author summary Leptospirosis which is an emerging zoonotic disease worldwide, is transmitted to humans through contact with soils or surface waters contaminated with the urine of reservoir animals. Species of Leptospira, which include infectious and non-infectious strains, are ubiquitous in the environment. In this study we have sequenced the genomes of strains of Leptospira isolated from several environmental sources worldwide. Comparison of these genomes with other members of the Leptospira genus revealed the existence of 30 novel Leptospira species. A comparative genomic analysis of species of the genus allowed us to identify genes or genome features that are specific of infectious species, providing insights into virulence evolution in these atypical bacteria but also allow refinement of the Leptospira classification.