First report of Culicoides caucoliberensis in Spain: Exploring molecular phylogeny, host-feeding behaviour and avian haemosporidian parasites.

Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of pathogens that affect wildlife and livestock. Understanding the composition and distribution of vector species is crucial for implementing control strategies and preventing the spread of infectious diseases. This study provides a morphological and molecular characterisation of Culicoides caucoliberensis, which represents the first record for Spain, increasing the number of Culicoides species in the country to 85. A total of 213 specimens were collected using Onderstepoort-ultraviolet down-draught light traps on a rocky coastline in the Balearic Islands during two sampling periods in 2022. Phylogenetic analysis showed that C. caucoliberensis forms a monophyletic cluster within the Maritimus group. Host preferences were determined for the first time and showed propensity to feed on the European shag (Phalacrocorax aristotelis). The vector role of C. caucoliberensis for haemosporidian transmission remains unclear since molecular detection of Haemosporidians (Haemoproteus and Plasmodium) was negative for all the pools of parous and engorged females analysed. This study emphasises the importance of conducting entomofauna studies in lesser-known Mediterranean islet landscapes and highlights the need for research on vectors within the One Health framework.

The use of path analysis to determine effects of environmental factors on the adult seasonality of Culicoides (Diptera: Ceratopogonidae) vector species in Spain.

Culicoides biting midges (Diptera: Ceratopogonidae) are the main vectors of livestock diseases such as bluetongue (BT) which mainly affect sheep and cattle. In Spain, bluetongue virus (BTV) is transmitted by several Culicoides taxa, including Culicoides imicola, Obsoletus complex, Culicoides newsteadi and Culicoides pulicaris that vary in seasonality and distribution, affecting the distribution and dynamics of BT outbreaks. Path analysis is useful for separating direct and indirect, biotic and abiotic determinants of species' population performance and is ideal for understanding the sensitivity of adult Culicoides dynamics to multiple environmental drivers. Start, end of season and length of overwintering of adult Culicoides were analysed across 329 sites in Spain sampled from 2005 to 2010 during the National Entomosurveillance Program for BTV with path analysis, to determine the direct and indirect effects of land use, climate and host factor variables. Culicoides taxa had species-specific responses to environmental variables. While the seasonality of adult C. imicola was strongly affected by topography, temperature, cover of agro-forestry and sclerophyllous vegetation, rainfall, livestock density, photoperiod in autumn and the abundance of Culicoides females, Obsoletus complex species seasonality was affected by land-use variables such as cover of natural grassland and broad-leaved forest. Culicoides female abundance was the most explanatory variable for the seasonality of C. newsteadi, while C. pulicaris showed that temperature during winter and the photoperiod in November had a strong effect on the start of the season and the length of overwinter period of this species. These results indicate that the seasonal vector-free period (SVFP) in Spain will vary between competent vector taxa and geographic locations, dependent on the different responses of each taxa to environmental conditions.

Larvae ecology and adult activity of Aedes mariae (Diptera: Culicidae) in a touristic rock-pool area of the Balearic Islands (Western Mediterranean).

Mosquitoes are vectors of several diseases of medical concern such as malaria or dengue and can also negatively affect tourism and the life-quality of the neighbourhood. The species Aedes mariae (Sergent and Sergent, 1903) is a poorly studied mosquito that breeds in rock-pools of the Mediterranean coast. General Linear Mixed Models (GLMM) were used to determine drivers affecting the presence and abundance of this species. Abiotic and biotic factors were recorded in rock-pools with the presence of Ae. mariae sub-adults across a supralittoral area of Majorca Island (Balearic Islands, Spain) from July 2018 to June 2019. We tested how abiotic factors affected the presence of larvae, while the biotic factors were used to check their effect on larvae abundance. human landing collection was also conducted to assess the adult activity of this species. Valuable data were recorded to improve our knowledge about the bioecology of Ae. mariae in a touristic area of the island of Majorca. Salinity and pH were the most explanatory variables for the presence of Ae. mariae larvae. The presence of Posidonia oceanica (L.) Delile 1813 leaves negatively affected the abundance of Ae. mariae larvae while the presence of other fauna enhanced it. Adult females of Ae. mariae were active for 26 min after sunset in June and its host-seeking activity decreased during autumn months. Control methods against this species should be focussed on rock-pools and planning treatments according to tides, waves and precipitation.

Modelling the range expansion of the Tiger mosquito in a Mediterranean Island accounting for imperfect detection.

BACKGROUNDS: Aedes albopictus (Diptera; Culicidae) is a highly invasive mosquito species and a competent vector of several arboviral diseases that have spread rapidly throughout the world. Prevalence and patterns of dispersal of the mosquito are of central importance for an effective control of the species. We used site-occupancy models accounting for false negative detections to estimate the prevalence, the turnover, the movement pattern and the growth rate in the number of sites occupied by the mosquito in 17 localities throughout Mallorca Island. RESULTS: Site-occupancy probability increased from 0.35 in the 2012, year of first reported observation of the species, to 0.89 in 2015. Despite a steady increase in mosquito presence, the extinction probability was generally high indicating a high turnover in the occupied sites. We considered two site-dependent covariates, namely the distance from the point of first observation and the estimated yearly occupancy rate in the neighborhood, as predicted by diffusion models. Results suggested that mosquito distribution during the first year was consistent with what predicted by simple diffusion models, but was not consistent with the diffusion model in subsequent years when it was similar to those expected from leapfrog dispersal events. CONCLUSIONS: Assuming a single initial colonization event, the spread of Ae. albopictus in Mallorca followed two distinct phases, an early one consistent with diffusion movements and a second consistent with long distance, 'leapfrog', movements. The colonization of the island was fast, with ~90% of the sites estimated to be occupied 3 years after the colonization. The fast spread was likely to have occurred through vectors related to human mobility such as cars or other vehicles. Surveillance and management actions near the introduction point would only be effective during the early steps of the colonization.

Surveillance and screening of Stomoxyinae flies from Mallorca Island (Spain) reveal the absence of selected pathogens but confirm the presence of the endosymbiotic bacterium Wolbachia pipientis.

Adult brachycera biting flies can significantly impact livestock through both direct effects (reduction of food intake, disturbance, painful bites, and blood loss) and indirect effects (pathogen transmission), leading to substantial economic losses and production damage. This study aimed to assess the presence of blood-sucking flies in six mixed-animal farm environments on the island of Mallorca (Balearic Islands, Spain) by employing multiple trapping methods. Additionally, distribution maps of brachycera biting fly species recorded in Spain were created, based on data extracted thorough review of scientific literature and citizen digital databases. Investigation of several pathogens, including equine infectious anemia virus (EIAV), Anaplasmataceae bacteria, and piroplasm protozoa, was carried out using different PCR targets (18S rRNA, 16S rRNA, groESL, and tat genes). Citizen science databases and literature review corroborated the consistent distribution trend for two Stomoxyinae species, underscoring the importance of citizen collaboration as a complement to traditional entomological surveillance. Our study confirmed the presence of two biting Stomoxyinae species: the prevalent stable fly Stomoxys calcitrans across all sampled farms, and the horn fly Haematobia irritans, which turned out to be less abundant. DNA barcoding techniques validated the identification of the two species. Neither EIAV nor bacterial/protozoan pathogens were detected using the selected PCR targets in either fly species. However, Wolbachia pipientis (clustered in the supergroup A together with the only sequence of W. pipientis from the USA) was identified through PCR targeting 16S rRNA, groESL and wsp genes in all pools of H. irritans (n = 13) collected from two of the examined farms. This study represents the first attempt to investigate pathogens in Stomoxyinae biting flies in Spain. The discovery of the endosymbiotic Wolbachia organism in H. irritans represents the first record in Spain and the second from Europe. This finding holds significant implications for future research on the applications of this bacterium in biocontrol programs.

Modelling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases.

Malaria remains one of the most important infectious diseases globally due to its high incidence and mortality rates. The influx of infected cases from endemic to non-endemic malaria regions like Europe has resulted in a public health concern over sporadic local outbreaks. This is facilitated by the continued presence of competent Anopheles vectors in non-endemic countries.We modelled the potential distribution of the main malaria vector across Spain using the ensemble of eight modelling techniques based on environmental parameters and the Anopheles maculipennis s.l. presence/absence data collected from 2000 to 2020. We then combined this map with the number of imported malaria cases in each municipality to detect the geographic hot spots with a higher risk of local malaria transmission.The malaria vector occurred preferentially in irrigated lands characterized by warm climate conditions and moderate annual precipitation. Some areas surrounding irrigated lands in northern Spain (e.g. Zaragoza, Logroño), mainland areas (e.g. Madrid, Toledo) and in the South (e.g. Huelva), presented a significant likelihood of A. maculipennis s.l. occurrence, with a large overlap with the presence of imported cases of malaria.While the risk of malaria re-emergence in Spain is low, it is not evenly distributed throughout the country. The four recorded local cases of mosquito-borne transmission occurred in areas with a high overlap of imported cases and mosquito presence. Integrating mosquito distribution with human incidence cases provides an effective tool for the quantification of large-scale geographic variation in transmission risk and pinpointing priority areas for targeted surveillance and prevention.

Semiclassical relativistic stars.

We present strong evidence that semiclassical gravity can give place to self-consistent ultracompact stars beyond the Buchdahl limit. We integrate the semiclassical equations of (spherically symmetric) stellar equilibrium for a constant-density classical fluid. The semiclassical contribution is modelled by a quantum massless scalar field in the only static vacuum state compatible with asymptotic flatness (Boulware vacuum). The Renormalized Stress-Energy Tensor (RSET) is firstly approximated by the analytic Polyakov approximation. This already reveals a crucial difference with respect to purely classical solutions: stars with compactness close to that of a black hole exhibit bounded pressures and curvatures up to a very small central core compared with the star radius. This suggests that a more refined approximation to the RSET at the core may give rise to strictly regular configurations. Following this suggestion, we prove that a minimal deformation of the Polyakov approximation inside the central core is sufficient to produce regular ultracompact stellar configurations.

A Survey on Native and Invasive Mosquitoes and Other Biting Dipterans in Northern Spain.

PURPOSE: Haematophagous Diptera, such as mosquitoes (Culicidae), biting midges (Ceratopogonidae), and black flies (Simuliidae), are important insects for public and animal health due to their capacity to bite and transmit pathogens. Outdoor recreation areas are usually affected by biting species and provide suitable habitats to both adult and immature stages. This study aimed to determine the species diversity and larval sites of these Diptera groups in two golf courses. METHODS: A multi-method collection approach using ultraviolet-CDC traps, human landing catches, collection in breeding sites, and ovitraps was implemented during summer 2020 in northern Spain. Insects were determined by morphological features accompanied by DNA barcoding. RESULTS: A total of ten native mosquito species were recorded either as adults or as larval stages. The invasive species Aedes japonicus was collected only at egg or pupa stage in ovitraps. Culex pipiens s.l. and Culex torrentium were both common mosquito species accounting for 47.9% of the total larval site collections and their larvae might be found in a wide range of natural and artificial sites. Culiseta longiareolata specimens were also prominent (30.1% of the total) and occurred exclusively in man-made water-filled containers. A total of 13 Culicoides species were identified, 10 of which were captured by ultraviolet-CDC traps, particularly members of the Obsoletus complex (Culicoides obsoletus/Culicoides scoticus, 74.9%) and seven species by emergence traps, being the two most abundant C. kibunensis (44.8%) and C. festivipennis (34.9%). Simulium cryophilum was also collected hovering around the operator under field sampling. CONCLUSION: A comprehensive representation of the blood-sucking Diptera fauna and their larval sites was obtained by the multi-method approach in two Spanish golf courses.

Publishing data to support the fight against human vector-borne diseases.

Vector-borne diseases are responsible for more than 17% of human cases of infectious diseases. In most situations, effective control of debilitating and deadly vector-bone diseases (VBDs), such as malaria, dengue, chikungunya, yellow fever, Zika and Chagas requires up-to-date, robust and comprehensive information on the presence, diversity, ecology, bionomics and geographic spread of the organisms that carry and transmit the infectious agents. Huge gaps exist in the information related to these vectors, creating an essential need for campaigns to mobilise and share data. The publication of data papers is an effective tool for overcoming this challenge. These peer-reviewed articles provide scholarly credit for researchers whose vital work of assembling and publishing well-described, properly-formatted datasets often fails to receive appropriate recognition. To address this, GigaScience's sister journal GigaByte partnered with the Global Biodiversity Information Facility (GBIF) to publish a series of data papers, with support from the Special Programme for Research and Training in Tropical Diseases (TDR), hosted by the World Health Organisation (WHO). Here we outline the initial results of this targeted approach to sharing data and describe its importance for controlling VBDs and improving public health.

AIMSurv: First pan-European harmonized surveillance of Aedes invasive mosquito species of relevance for human vector-borne diseases.

Human and animal vector-borne diseases, particularly mosquito-borne diseases, are emerging or re-emerging worldwide. Six Aedes invasive mosquito (AIM) species were introduced to Europe since the 1970s: Aedes aegypti, Ae. albopictus, Ae. japonicus, Ae. koreicus, Ae. atropalpus and Ae. triseriatus. Here, we report the results of AIMSurv2020, the first pan-European surveillance effort for AIMs. Implemented by 42 volunteer teams from 24 countries. And presented in the form of a dataset named "AIMSurv Aedes Invasive Mosquito species harmonized surveillance in Europe. AIM-COST Action. Project ID: CA17108". AIMSurv2020 harmonizes field surveillance methodologies for sampling different AIMs life stages, frequency and minimum length of sampling period, and data reporting. Data include minimum requirements for sample types and recommended requirements for those teams with more resources. Data are published as a Darwin Core archive in the Global Biodiversity Information Facility- Spain, comprising a core file with 19,130 records (EventID) and an occurrences file with 19,743 records (OccurrenceID). AIM species recorded in AIMSurv2020 were Ae. albopictus, Ae. japonicus and Ae. koreicus, as well as native mosquito species.

Analogue Gravity.

Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for) gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing) and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity).

Environmental Drivers of Adult Seasonality and Abundance of Biting Midges Culicoides (Diptera: Ceratopogonidae), Bluetongue Vector Species in Spain.

Bluetongue is a viral disease affecting wild and domestic ruminants transmitted by several species of biting midges Culicoides Latreille. The phenology of these insects were analyzed in relation to potential environmental drivers. Data from 329 sites in Spain were analyzed using Bayesian Generalized Linear Mixed Model (GLMM) approaches. The effects of environmental factors on adult female seasonality were contrasted. Obsoletus complex species (Diptera: Ceratopogonidae) were the most prevalent across sites, followed by Culicoides newsteadi Austen (Diptera: Ceratopogonidae). Activity of female Obsoletus complex species was longest in sites at low elevation, with warmer spring average temperatures and precipitation, as well as in sites with high abundance of cattle. The length of the Culicoides imicola Kieffer (Diptera: Ceratopogonidae) female adult season was also longest in sites at low elevation with higher coverage of broad-leaved vegetation. Long adult seasons of C. newsteadi were found in sites with warmer autumns and higher precipitation, high abundance of sheep. Culicoides pulicaris (Linnaeus) (Diptera: Ceratopogonidae) had longer adult periods in sites with a greater number of accumulated degree days over 10°C during winter. These results demonstrate the eco-climatic and seasonal differences among these four taxa in Spain, which may contribute to determining sites with suitable environmental circumstances for each particular species to inform assessments of the risk of Bluetongue virus outbreaks in this region.

At the tip of an iceberg: citizen science and active surveillance collaborating to broaden the known distribution of Aedes japonicus in Spain.

BACKGROUND: Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, however, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert. METHODS: The collaboration between Mosquito Alert, the Ministry of Health, local authorities and academic researchers resulted in a multi-source surveillance combining active field sampling with broader temporal and spatial citizen-sourced data, resulting in a more flexible and efficient surveillance strategy. RESULTS: Between 2018 and 2020, the joint efforts of administrative bodies, academic teams and citizen-sourced data led to the discovery of this species in northern regions of Spain such as Cantabria and the Basque Country. This raised the estimated area of occurrence of Ae. japonicus from < 900 km2 in 2018 to > 7000 km2 in 2020. CONCLUSIONS: This population cluster is geographically isolated from any other population in Europe, which raises questions about its origin, path of introduction and dispersal means, while also highlighting the need to enhance surveillance systems by closely combining crowd-sourced surveillance with public health and mosquito control agencies' efforts, from local to continental scales. This multi-actor approach for surveillance (either passive and active) shows high potential efficiency in the surveillance of other invasive mosquito species, and specifically the major vector Aedes aegypti which is already present in some parts of Europe.

Molecular Characterization of Mosquito Diversity in the Balearic Islands.

Several outbreaks of mosquito-borne diseases have taken place in Europe in recent years. In Spain, both active and passive surveillance have demonstrated that dengue and West Nile viruses are currently circulating, and seven autochthonous dengue cases have been reported in the last 2 yr. The effectiveness of vector control programs largely depends on the accuracy of the taxonomic identification of the species. However, in Spain, identification almost completely relies on the use of morphological keys to characterize the mosquito fauna. This study investigates the congruence between molecular and morphological species boundaries in 13 Spanish mosquito taxa. The Cytochrome c oxidase subunit I (COI) gene region was sequenced from 60 adult specimens collected in Mallorca, plus several representatives from other Spanish regions for comparative purposes. Phylogenetic relationships were established using Bayesian and maximum-likelihood approaches. Using three species delimitation algorithms (ABGD, mPTP, and GMYC), we found strong evidence for cryptic speciation within Anopheles algeriensis Theobald, a widespread mosquito in the Mediterranean basin. We also delimited the Mallorcan rock pool mosquito Aedes mariae (Sergent & Sergent), from mainland European populations. Finally, we found difficulties in the use of wing characters in species keys to distinguish Culiseta annulata (Schrk) from Culiseta subochrea (Edwards). Given that these species are vectors of pathogens of medical relevance and have veterinary importance, their accurate taxonomic identification is essential in European vector surveillance programs.

A Mondrian matrix of seasonal patterns of Culicoides nulliparous and parous females at different latitudes in Spain.

Insects from genus Culicoides (Diptera; Ceratopogonidae) transmit arboviruses such as Bluetongue virus (BTV); affecting wild and domestic ruminants. These insects are age graded for monitoring purposes in surveillance programs. Parous females (PF) are the only fraction of the entire population that could effectively transmit viruses in a subsequent blood meal. Data of the Spanish Entomosurveillance National Program from 2008 to 2010 were used to analyse the seasonal pattern of the nulliparous females (NF) and PF of the vector species Obsoletus complex, C. imicola, C. newsteadi and C. pulicaris. Latitude variation on the seasonal abundance patterns of PF was also analysed in trap sites spanning a North-South axis in mainland Spain. The weekly abundance of PF was always highest in summer. The peak of abundance mainly occurred between April and July except for C. imicola that was from September to November. The analysis of the latitudinal seasonal variation of PF in Spain showed that Northern provinces have absence of C. imicola while the Obsoletus species were more present in Northern areas. There were periods of the year were no individuals of any vector species were collected, which should be considered in order to calculate the Seasonally Vector-Free Period (SVFP). Culicoides newsteadi and C. pulicaris exhibited the highest population in Toledo, probably related to their inland preferences. These findings would be of interest for a better understanding of the periods of low and high risk of transmission of BTV in Spain.

Modelling the monthly abundance of Culicoides biting midges in nine European countries using Random Forests machine learning.

BACKGROUND: Culicoides biting midges transmit viruses resulting in disease in ruminants and equids such as bluetongue, Schmallenberg disease and African horse sickness. In the past decades, these diseases have led to important economic losses for farmers in Europe. Vector abundance is a key factor in determining the risk of vector-borne disease spread and it is, therefore, important to predict the abundance of Culicoides species involved in the transmission of these pathogens. The objectives of this study were to model and map the monthly abundances of Culicoides in Europe. METHODS: We obtained entomological data from 904 farms in nine European countries (Spain, France, Germany, Switzerland, Austria, Poland, Denmark, Sweden and Norway) from 2007 to 2013. Using environmental and climatic predictors from satellite imagery and the machine learning technique Random Forests, we predicted the monthly average abundance at a 1 km2 resolution. We used independent test sets for validation and to assess model performance. RESULTS: The predictive power of the resulting models varied according to month and the Culicoides species/ensembles predicted. Model performance was lower for winter months. Performance was higher for the Obsoletus ensemble, followed by the Pulicaris ensemble, while the model for Culicoides imicola showed a poor performance. Distribution and abundance patterns corresponded well with the known distributions in Europe. The Random Forests model approach was able to distinguish differences in abundance between countries but was not able to predict vector abundance at individual farm level. CONCLUSIONS: The models and maps presented here represent an initial attempt to capture large scale geographical and temporal variations in Culicoides abundance. The models are a first step towards producing abundance inputs for R0 modelling of Culicoides-borne infections at a continental scale.

Clinical experience with the application of distraction osteogenesis for airway obstruction.

OBJECTIVES: The objective of this study was to evaluate the long-term success of mandibular distraction osteogenesis in patients with mandibular airway obstruction syndrome (MAOS), defined as obstructive sleep apnea, swallowing abnormalities, and failure to thrive in the presence of micrognathia, glossoptosis, gastroesophageal or laryngeal reflux, and microaspiration. This is a cross-sectional study at the International Craniofacial Institute in the Medical City Hospital, Dallas, TX. From January 1997 to July 2008, a group of 81 patients were examined for MAOS using medical history and physical examination. They all met the criteria for a multidisciplinary team evaluation consisting of upper airway endoscopy, swallowing evaluations, standard overnight polysomnography, and radiologic evaluations of the airway and craniofacial structures. MATERIALS AND METHODS: In the 81 patients examined, Pierre Robin Sequence was diagnosed in 65; micrognathia and glossoptosis without cleft palate, in 13; and micrognathia as a component of a craniofacial syndrome (Treacher Collins syndrome), in 3. A total of 45 patients were documented to have gastroesophageal or laryngeal reflux.Only 41 patients had yet to receive any treatment at the time of evaluation; 40 patients presented with a tracheotomy.Of the 41 untreated patients, 14 responded to conservative treatment; Pierre Robin syndrome was diagnosed in all of them, and they did not require mandibular distraction or other surgical procedure to improve the MAOS.Bilateral distraction osteogenesis of the mandible was performed in 67 patients; 27 were younger than 6 months at the beginning of the distraction, and 40 were older than 6 months (mean age at distraction, 1.2 yr). Of this group, 26 patients did not have any prior surgical treatment, and 41 patients already had a tracheotomy. The distraction devices used were internal in 33 (49.26%) and external in 34 (50.74%) of 67 patients. The distraction protocol consisted of a 24-hour latency period and then a 1-mm/d activation period. The mean activation period was 19.4 days (range, 10-27 d), the mean consolidation period was 73 days, and the mean length of distraction was 22 mm (range, 10-32 mm). RESULTS: Tracheostomy was prevented in 25 (96%) of 26 patients, and decannulation after distraction was possible in 38 (92%) of 41 patients. Success, defined as decannulation within 1 year of the start of distraction or prevention of tracheostomy in a patient otherwise deemed as a candidate, was found in 63 (94%) of 67 patients. Oral feedings have been resumed in 61 (91%) of 67 patients.Complications observed were mostly related to pin site infections requiring antibiotics. Device failure was experienced in 2 (3%) of 66 internal devices and in 7 (10.2%) of 68 external devices.Distraction osteogenesis of the mandible provides an excellent treatment for mandibular airway obstruction in patients younger than 6 years who do not respond to conservative measures and allows for early decannulation in patients who previously underwent tracheotomy.

Robust Detection of Audio-Cough Events Using Local Hu Moments.

Telehealth has shown potential to improve access to healthcare cost-effectively in respiratory illness. However, it has failed to live up to expectation, in part because of poor objective measures of symptoms such as cough events, which could lead to early diagnosis or prevention. Considering the burden that these conditions constitute for national health systems, an effort is needed to foster telehealth potential by developing low-cost technology for efficient monitoring and analysis of cough events. This paper proposes the use of local Hu moments as a robust feature set for automatic cough detection in smartphone-acquired audio signals. The final system feeds a k-nearest-neighbor classifier with the extracted features. To properly evaluate the system in a diversity of noisy backgrounds, we contaminated real cough audio data with a variety of sounds including noise from both indoor and outdoor environments and noncough events (sneeze, laugh, speech, etc.). The created database allows flexible settings of signal-to-noise ratio levels between background sounds and events (cough and noncough). This evaluation was complemented using real patient data from an outpatient clinic. The system is able to detect cough events with high sensitivity (up to 88.51%) and specificity (up to 99.77%) in a variety of noisy environments, overcoming other state-of-the-art audio features. Our proposal paves the way for ubiquitous cough monitoring with minimal disruption in daily activities.

A Machine Hearing System for Robust Cough Detection Based on a High-Level Representation of Band-Specific Audio Features.

Cough is a protective reflex conveying information on the state of the respiratory system. Cough assessment has been limited so far to subjective measurement tools or uncomfortable (i.e., non-wearable) cough monitors. This limits the potential of real-time cough monitoring to improve respiratory care. OBJECTIVE: This paper presents a machine hearing system for audio-based robust cough segmentation that can be easily deployed in mobile scenarios. METHODS: Cough detection is performed in two steps. First, a short-term spectral feature set is separately computed in five predefined frequency bands: [0, 0.5), [0.5, 1), [1, 1.5), [1.5, 2), and [2, 5.5125] kHz. Feature selection and combination are then applied to make the short-term feature set robust enough in different noisy scenarios. Second, high-level data representation is achieved by computing the mean and standard deviation of short-term descriptors in 300 ms long-term frames. Finally, cough detection is carried out using a support vector machine trained with data from different noisy scenarios. The system is evaluated using a patient signal database which emulates three real-life scenarios in terms of noise content. RESULTS: The system achieves 92.71% sensitivity, 88.58% specificity, and 90.69% Area Under Receiver Operating Charcteristic (ROC) curve (AUC), outperforming state-of-the-art methods. CONCLUSION: Our research outcome paves the way to create a device for cough monitoring in real-life situations. SIGNIFICANCE: Our proposal is aligned with a more comfortable and less disruptive patient monitoring, with benefits for patients (allows self-monitoring of cough symptoms), practitioners (e.g., assessment of treatments or better clinical understanding of cough patterns), and national health systems (by reducing hospitalizations).

Efficient k-NN Implementation for Real-Time Detection of Cough Events in Smartphones.

The potential of telemedicine in respiratory health care has not been completely unveiled in part due to the inexistence of reliable objective measurements of symptoms such as cough. Currently available cough detectors are uncomfortable and expensive at a time when generic smartphones can perform this task. However, two major challenges preclude smartphone-based cough detectors from effective deployment namely, the need to deal with noisy environments and computational cost. This paper focuses on the latter, since complex machine learning algorithms are too slow for real-time use and kill the battery in a few hours unless specific actions are taken. In this paper, we present a robust and efficient implementation of a smartphone-based cough detector. The audio signal acquired from the device's microphone is processed by computing local Hu moments as a robust feature set in the presence of background noise. We previously demonstrated that pairing Hu moments and a standard k-NN classifier achieved accurate cough detection at the expense of computation time. To speed-up k-NN search, many tree structures have been proposed. Our cough detector uses an improved vantage point (vp)-tree with optimized construction methods and a distance function that results in faster searches. We achieve 18× speed-up over classic vp-trees, and 560× over standard implementations of k-NN in state-of-the-art machine learning libraries, with classification accuracies over 93%, enabling real-time performance on low-end smartphones.