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Microtidal river mouths are dynamic environments that evolve as a consequence of many forcing actions. Under the hydrodynamic viewpoint, river currents, sea waves and tides strongly interact, and their interplay determines specific sediment transport and morphological patterns. Beyond literature evidence, information comes from field observations made at the Misa River study site, a microtidal river along the Adriatic Sea (Italy), object of a long-going monitoring. The river runs for 48 km in a watershed of 383 km2, providing a discharge of about 400 m3/s for return periods of 100 years. The overall hydrodynamics, sediment transport and morphological evolution at the estuary are analyzed with particular attention to specific issues like: the generation of vortical flows at the river mouth, the influence of various wave modes (infragravity to tidal) propagating upriver, the role of sediment flocculation, the generation and evolution of bed features (river-mouth bars and longitudinal nearshore bars). Numerical simulations are also used to clarify specific mechanisms of interest.

On the basis of observations and modelling of the plume generated by the Misa River (AN, Italy), we performed a comprehensive study, which integrated different sources of information (field data, numerical simulations, etc.), of the generation and transport mechanisms of river plumes flowing into microtidal environments. First, we analysed images simultaneously acquired by both two shore-based stations and satellite to determine plume fronts and extensions. Then, we correlated such information with the estuarine forcing to recognize the plume generation and transport mechanisms. Being real-life events influenced by a combination of factors, we run numerical simulations to separately study each force and its influence on the plume evolution. We also performed simulations of two real-life cases, to compare the modelled and observed results. We identified the river discharge and the wind as the main generation and transport mechanisms, respectively. Moreover, waves could stir, suspend, and drag plume sediments, even if results showed that a river discharge associated with a return period smaller than 1 year produced a plume denser than 5-year return period waves. The transport mechanisms were responsible for the alongshore extension of the plume. The tide, even if secondarily, affected the plume evolution, depending on its phase shift to the river discharge peak. Particle Tracking Velocimetry from videos acquired by a shore-based station provided the surface velocity field in the final river stretch. This and the contributions by wind and waves were correlated with the plume extension through a power law.

The two most efficient and most recently radiated Afrotropical vectors of human malaria – Anopheles coluzzii and An. gambiae – are identified by single‐locus diagnostic PCR assays based on species‐specific markers in a 4 Mb region on chromosome‐X centromere. Inherently, these diagnostic assays cannot detect interspecific autosomal admixture shown to be extensive at the westernmost and easternmost extremes of the species range. The main aim of this study was to develop novel, easy‐to‐implement tools for genotyping An. coluzzii and An. gambiae‐specific ancestral informative markers (AIMs) identified from the Anopheles gambiae 1000 genomes (Ag1000G) project. First, we took advantage of this large set of data in order to develop a multilocus approach to genotype 26 AIMs on all chromosome arms valid across the species range. Second, we tested the multilocus assay on samples from Guinea Bissau, The Gambia and Senegal, three countries spanning the westernmost hybridization zone, where conventional species diagnostic is problematic due to the putative presence of a novel “hybrid form”. The multilocus assay was able to capture patterns of admixture reflecting those revealed by the whole set of AIMs and provided new original data on interspecific admixture in the region. Third, we developed an easy‐to‐use, cost‐effective PCR approach for genotyping two AIMs on chromosome‐3 among those included in the multilocus approach, opening the possibility for advanced identification of species and of admixed specimens during routine large scale entomological surveys, particularly, but not exclusively, at the extremes of the range, where WGS data highlighted unexpected autosomal admixture.

Sensitive techniques for the detection of Plasmodium (Aconoidasida: Plasmodiidae) sporozoites in field-collected malaria vectors are essential for the correct assessment of risk for malaria transmission. A real-time polymerase chain reaction (RT-PCR) protocol targeting Plasmodium mtDNA proved to be much more sensitive in detecting sporozoites in mosquitoes than the widely used enzyme-linked immunosorbent assay targeting Plasmodium circumsporozoite protein (CSP-ELISA). However, because of the relatively high costs associated with equipment and reagents, RT-PCRs are mostly used to assess the outcomes of experimental infections in the frame of research experiments, rather than in routine monitoring of mosquito infection in the field. The present authors developed a novel mtDNA-based nested PCR protocol, modified from a loop-mediated isothermal amplification (LAMP) assay for Plasmodium recognition in human blood samples, and compared its performance with that of routinely used CSP-ELISAs in field-collected Anopheles coluzzii (Diptera: Culicidae) samples. The nested PCR showed 1.4-fold higher sensitivity than the CSP-ELISA. However, nested PCR results obtained in two laboratories and in different replicates within the same laboratory were not 100% consistent, probably because the copy number of amplifiable Plasmodium mtDNA was close in some specimens to the threshold of nested PCR sensitivity. This implies that Plasmodium-positive specimens should be confirmed by a second nested PCR to avoid false positives. Overall, the results emphasize the need to use molecular approaches to obtain accurate estimates of the actual level of Plasmodium circulation within malaria vector populations.

We conducted, for the first time, a study of the long-term evolution of an inner mouth bar in a microtidal environment that complements field observations with detailed numerical modelling of the same morphodynamics. Images collected by a video-monitoring station, from 2016 to 2019, were processed to study the evolution of a persistent inner mouth bar formed inside the highly engineered Misa River estuary (Senigallia, Italy) after years of reduced precipitation and discharges. We developed a semi-automatic procedure to detect the emerged area of this deposit. We seek to quantify the relationship between the long-term evolution of the bar and the forcing from the river, waves and tides. The observed high peaks in river discharge caused a strong downriver bar migration (i.e. almost twice the river width). Conversely, the observed sea storms produced an upriver bar migration smaller than one river width. A much slower and weaker (less than half the river width) upriver migration was also observed during periods of large area accretion and due to mild wave climate. Moreover, results showed that the sea water level variation did not directly impact the morphodynamics of the estuary, affecting the emerged portion of the bar only. Numerical simulations, run with Delft3D, were used to complete the information coming from field observations. After some checks on the proper use of the solver for the scenarios and environments of interest, some parametric simulations were run to highlight the role of the different forcing on the bed evolution. Simulations showed, as expected, erosion of the riverbed and significant downriver migrations (four river widths) during peaks of river discharge comparable to the 1-year return period discharges. Numerical results also showed upriver sediment transport when the wave forcing was dominant, with 10-years return period waves inducing an upriver bar migration in the order of one river width. Then, one real-life event was simulated to inspect the interaction of the various forcing and to compare their effects with the observations. Our analysis provides new insight into the complex morphodynamics in a microtidal estuary when weak river discharge is opposed by sea waves driving upriver sediment transport. A more thorough understanding of the morphodynamics is needed for future forecasting of the formation and evolution of sediment deposits inside estuarine channels that can inhibit both navigation and the flux of sediment from the river to the estuary.

Background Despite the overall major impact of long-lasting insecticide treated nets (LLINs) in eliciting individual and collective protection to malaria infections, some sub-Saharan countries, including Burkina Faso, still carry a disproportionately high share of the global malaria burden. This study aims to analyse the possible entomological bases of LLIN limited impact, focusing on a LLIN-protected village in the Plateau Central region of Burkina Faso. Methods Human landing catches (HLCs) were carried out in 2015 for 12 nights both indoors and outdoors at different time windows during the highest biting activity phase for Anopheles gambiae (s.l.). Collected specimens were morphologically and molecularly identified and processed for Plasmodium detection and L1014F insecticide-resistance allele genotyping. Results Almost 2000 unfed An. gambiae (s.l.) (54% Anopheles coluzzii and 44% Anopheles arabiensis) females landing on human volunteers were collected, corresponding to a median number of 23.5 females/person/hour. No significant differences were observed in median numbers of mosquitoes collected indoors and outdoors, nor between sporozoite rates in An. coluzzii (6.1%) and An. arabiensis (5.5%). The estimated median hourly entomological inoculation rate (EIR) on volunteers was 1.4 infective bites/person/hour. Results do not show evidence of the biting peak during night hours typical for An. gambiae (s.l.) in the absence of bednet protection. The frequency of the L1014F resistant allele (n = 285) was 66% in An. coluzzii and 38% in An. arabiensis. Conclusions The observed biting rate and sporozoite rates are in line with the literature data available for An. gambiae (s.l.) in the same geographical area before LLIN implementation and highlight high levels of malaria transmission in the study village. Homogeneous biting rate throughout the night and lack of preference for indoor-biting activity, suggest the capacity of both An. coluzzii and An. arabiensis to adjust their host-seeking behaviour to bite humans despite bednet protection, accounting for the maintenance of high rates of mosquito infectivity and malaria transmission. These results, despite being limited to a local situation in Burkina Faso, represent a paradigmatic example of how high densities and behavioural plasticity in the vector populations may contribute to explaining the limited impact of LLINs on malaria transmission in holo-endemic Sudanese savannah areas in West Africa.

Video-monitoring can be exploited as a valuable tool to acquire continuous, high-quality information on the evolution of beach morphology at a low cost and, on such basis, perform beach resilience analyses. This manuscript presents preliminary results of an ongoing, long-term monitoring programme of five sandy Italian beaches along the Adriatic and Tyrrhenian sea. The project aims at analyzing nearshore morphologic variabilities on a time period of several years, to link them to resilience indicators. The observations indicate that most of the beach width variations can be linked to discrete variations of sandbar systems, and most of all to an offshore migration and decay of the outermost bars. Further, the largest net shoreline displacements across the observation period are experienced by beaches with a clear NOM (Net Offshore Migration)-type evolution of the seabed.

Novel observations of bar features and migration patterns at three Italian sandy beaches in Senigallia (central Adriatic Sea) and Terracina (central Tyrrhenian Sea) are presented. While two of these beaches are unprotected, one is artificially embayed through the presence of a concrete jetty. Bar locations and motions are analysed with video imagery data sets from coastal monitoring stations. Wave climate from the Copernicus oceanographic model is used to correlate hydrodynamics and beach morphology. Clear net offshore migration (NOM) patterns are identified at all beaches, although exhibiting different response scales. At the low-slope beach of Senigallia (mean surf zone slope of 0.009) bars are more sensitive to seasonal changes in wave climate, with offshore shifts in winter and inactivity in summer. Mean annual migration rates of up to 0.26 m/day and 0.09 m/day are observed for outer and inner bars, respectively. No significant response to single storms is observed, except during a single NNE storm. No distinct erosive or accretive trend for the shoreline is evidenced. At the steep beach of Terracina (mean surf zone slope of 0.018), conversely, bars are strongly responsive to single storm events, with displacements of up to 25–50 m across a single storm. The mean inter-annual migration rate is 0.08 m/day for the single/outer bar, whereas a slight onshore trend (-0.02 m/day) for the newborn inner bar is established. The presence of an artificial jetty at the Misa river mouth in Senigallia, finally, leaves the bar system, typically oscillating around an equilibrium position, susceptible to larger seasonal oscillations and strong offshore migration due to two ESE storm events. Numerical simulations of nearshore circulation for two storms from different directions predict the birth of longshore currents, higher ratios of significant wave height to water depth, and stronger bottom orbital velocities over bars in case of the ESE storm, suggesting a greater tendency for offshore-directed sediment transport.

This paper presents the COPEMAP project, fruit of a research collaboration between the Universita Politecnica delle Marche and the Istituto Superiore per la Protezione e la Ricerca Ambientale. The project focuses on developing a methodology for the assessment of beach resilience as a function of both natural forcing (e.g. incoming wave fields) and natural protection (e.g. underwater sand bars). This is accomplished through simplified analyses of available video-monitoring data.

Despite the effectiveness of mass distribution of long-lasting insecticidal nets (LLINs) in reducing malaria transmission in Africa, in hyperendemic areas such as Burkina Faso the burden of malaria remains high. We here report the results of a 4-month survey on the feeding habits and Plasmodium infection in malaria vectors from a village in Burkina Faso one year following a national LLIN distribution programme. Low values of human blood index (HBI) observed in the major malaria vectors in the area (Anopheles coluzzii: N = 263, 20.1%; An. arabiensis: 5.8%, N = 103) are consistent with the hypothesis that LLINs reduced the availability of human hosts to mosquitoes. A regression meta-analysis of data from a systematic review of published studies reporting HBI and sporozoite rates (SR) for An. gambiae complex revealed that the observed SR values (An. coluzzii: 7.6%, N = 503; An. arabiensis: 5.3%, N = 225) are out of the ranges expected based on the low HBI observed. We hypothesize that a small fraction of inhabitants unprotected by bednets acts as a “core group” repeatedly exposed to mosquito bites, representing the major Plasmodium reservoir for the vectors, able to maintain a high risk of transmission even in a village protected by LLINs.

The accuracy of bathymetry estimated by optical implementations of remotely sensed depth inversion algorithms is in part related to the presence of optical wave signal in the images, which depend nonlinearly on the water surface slope. The signal to noise ratio in video images of waves decreases under large azimuthal angles between the camera and wave propagation direction, which can result in poor bathymetry estimation. We quantified errors in depth estimation by analysing the sensitivity of the optical implementation of cBathy v1.1, a widely applied algorithm for depth inversion in coastal regions, to wave viewing angle using synthetic tests. We found relative root mean square errors between 0.02 and 0.08 when the azimuthal angle between the camera look direction and wave approach was less than 75°. However, for higher azimuthal angles, the wave signal was dominated by short wavelengths in the optical images leading to larger depth errors (relative root mean square error = 0.2). We also investigated the sensitivity of the initial guess of the wave direction in the nonlinear solution used by the cBathy v1.1 algorithm to estimate water depth. Observed water depth errors caused by wave viewing angle or initial guess of the wave direction are shown in part to be related to errors in the estimates of frequency and wavenumber. The synthetic methodology and the results of the sensitivity analysis can be generalized to test the accuracy of depth estimation in shore-based video monitoring systems, to design future fixed camera coastal video monitoring stations or to drive the choice of the better viewing angles using small Unmanned Aerial Systems (sUAS) using the Matlab Toolbox we developed.