Human health and wellbeing and the health of the biosphere are inextricably linked. The state of Earth’s life-support systems, including freshwater, oceans, land, biodiversity, atmosphere, and climate, affect human health. At the same time, human activities are adversely affecting natural systems. This review paper is the outcome of an interdisciplinary workshop under the auspices of the Future Earth Health Knowledge Action Network (Health KAN). It outlines a research agenda to address cross-cutting knowledge gaps to further understanding and management of the health risks of these global environmental changes through an expert consultation and review process. The research agenda has four main themes: (1) risk identification and management (including related to water, hygiene, sanitation, and waste management); food production and consumption; oceans; and extreme weather events and climate change. (2) Strengthening climate-resilient health systems; (3) Monitoring, surveillance, and evaluation; and (4) risk communication. Research approaches need to be transdisciplinary, multi-scalar, inclusive, equitable, and broadly communicated. Promoting resilient and sustainable development are critical for achieving human and planetary health.

Mauritania is at the fringe of transmission of human schistosomiasis, which mainly occurs in the southern and southeastern parts of the country. This study aimed to assess the influence of rainfall seasonality on the prevalence of Schistosoma haematobium infection among school-aged children in Kaedi, southern Mauritania. Cross-sectional surveys (i.e. parasitological, malacological and observations on water-related human activities) were carried out in Kaedi between September 2014 and May 2015, during both the wet and dry seasons. A total of 2162 children aged 5–15 years provided a single urine sample that was subjected to S. haematobium diagnosis. Snails were sampled and checked for cercarial shedding. Water contact patterns of the local population were recorded by direct observation. The prevalence of S. haematobium was 4.0% (86/2162, 95% confidence interval (CI): 3.2–4.9%) with a geometric mean egg count per 10 ml of urine of 3.7 (95% CI: 2.8–4.3). Being male (adjusted odds ratio (aOR) 1.78, 95% CI: 1.13–2.80), being at primary school (aOR 1.73, 95% CI: 1.04–2.87) and dry season (aOR 0.56, 95% CI: 0.35–0.89) were significantly associated with S. haematobium. Among 284 potential intermediate host snail specimens collected over the rainy and dry seasons, three species were identified: Bulinus senegalensis (n = 13) and B. forskalii (n = 161) in the rainy season, and B. truncatus (n = 157) in the wet season. No snail was shedding cercariae. On average, seven human water contacts were recorded per hour per observer over a 28-day observation period. Twelve types of water contact activities were identified among which, swimming/bathing was predominant (n = 3788, 36.9%), followed by washing clothes (n = 2016, 19.7%) and washing dishes (n = 1322, 12.9%). Females (n = 5270, 51.4%) were slightly more in contact with water than males (n = 4983, 48.6%). The average time spent in the water per person per day was 14.2 min (95% CI: 13.8–14.6 min). The frequency and duration of water contact followed a seasonal pattern. Our findings demonstrate a low prevalence and intensity of S. haematobium among school-aged children in Kaedi. Appropriate integrated control measures, including health education among at-risk communities and snail control may help to interrupt transmission of S. haematobium in Kaedi.

Since 2000, substantial progress has been made in reducing malaria worldwide. However, some countries in West Africa remain a hotspot for malaria with all age groups at risk. Asymptomatic carriers of Plasmodium spp. are important sources of infections for malaria vectors and thus contribute to the anchoring of the disease in favourable eco-epidemiological settings. The objective of this study was to assess the asymptomatic malaria case rates in Korhogo and Kaedi, two urban areas in northern Côte d’Ivoire and southern Mauritania, respectively. Cross-sectional surveys were carried out during the rainy season in 2014 and the dry season in 2015 in both settings. During each season, 728 households were randomly selected and a household-based questionnaire was implemented to collect demographic and epidemiological data, including of malaria preventive methods used in communities. Finger-prick blood samples were obtained for biological examination using microscopy and rapid diagnostic tests (RDTs). Overall, 2672 households and 15 858 consenting participants were surveyed. Plasmodium spp. infection was confirmed in 12.4% (n = 832) and 0.3% (n = 22) of the assessed individuals in Korhogo and Kaedi, respectively. In Korhogo, the prevalence of asymptomatic malaria was 10.5% (95% CI: 9.7–11.2) as determined by microscopy and 9.3% (95% CI: 8.6–10.0%) when assessed by RDT. In Kaedi, asymptomatic malaria prevalence was 0.2% (95% CI: 0.1–0.4%) according to microscopy, while all RDTs performed were negative (n = 8372). In Korhogo, asymptomatic malaria infection was significantly associated with age and season, with higher risk within the 5–14 years-old, and during the rainy season. In Kaedi, the risk of asymptomatic malaria infection was associated with season only (higher during the dry season; crude OR (cOR): 6.37, 95% CI: 1.87–21.63). P. falciparum was the predominant species identified in both study sites representing 99.2% (n = 825) in Korhogo and 59.1% (n = 13) in Kaedi. Gametocytes were observed only in Korhogo and only during the rainy season at 1.3% (95% CI: 0.7–2.4%). Our findings show a low prevalence of clinical malaria episodes with a significant proportion of asymptomatic carriers in both urban areas. National policies for malaria infections are focused on treatment of symptomatic cases. Malaria control strategies should be designed for monitoring and managing malaria infections in asymptomatic carriers. Additional measures, including indoor residual spraying, effective use of long-lasting insecticidal nets is strongly needed to reduce the number of Plasmodium spp. infections in Korhogo and Kaedi.

Malaria continues to be a major public health concern with a substantial burden in Africa. Even though it has been widely demonstrated that malaria transmission is climate-driven, there have been very few studies assessing the relationship between climate variables and malaria transmission in Côte d’Ivoire. We used the VECTRI model to predict malaria transmission in southern Côte d’Ivoire. First, we tested the suitability of VECTRI in modeling malaria transmission using ERA5 temperature data and ARC2 rainfall data. We then used the projected climatic data pertaining to 2030, 2050, and 2080 from a set of 14 simulations from the CORDEX-Africa database to compute VECTRI outputs. The entomological inoculation rate (EIR) from the VECTRI model was well correlated with the observed malaria cases from 2010 to 2019, including the peaks of malaria cases and the EIR. However, the correlation between the two parameters was not statistically significant. The VECTRI model predicted an increase in malaria transmissions in both scenarios (RCP8.5 and RCP4.5) for the time period 2030 to 2080. The monthly EIR for RCP8.5 was very high (1.74 to 1131.71 bites/person) compared to RCP4.5 (0.48 to 908 bites/person). These findings call for greater efforts to control malaria that take into account the impact of climatic factors.

In addition to individual practices and access to water, sanitation, and hygiene (WASH) facilities, housing conditions may also be associated with the risk of diarrhea. Our study embraced a broad approach to health determinants by looking at housing deprivation characteristics as exposures of interest and confronting the latter’s spatial distribution to that of diarrheal cases. We tested the hypothesis that the risk of diarrhea in informal settlements is not only associated with WASH services, but also with inadequate dwelling characteristics, and that their spatial distributions follow similar patterns. We designed a cross-sectional study and collected primary data through georeferenced household surveys in two informal settlements in Abidjan, Côte d’Ivoire. We used local join count statistics to assess the spatial distribution of events and multiple logistic regressions to calculate adjusted odds ratios between diarrhea and exposures. A total of 567 households were enrolled. We found that constant access to basic WASH services, non-durable building materials, cooking outdoors, and water service discontinuity were associated with higher risks of diarrhea in the general population. The spatial distribution of diarrheal cases coincided with that of dwelling deprivation characteristics. We observed significant heterogeneity within the study sites regarding the spatial distribution of diarrheal cases and deprived dwellings. Along with WASH infrastructure, communities also need dignified housing to effectively prevent diarrhea. We recommend that decision-makers acknowledge a “spectrum” of deprivation within the heterogeneous universe of informal settlements, adopting a site-specific approach based on high-resolution data to address diarrhea and improve people’s well-being.