The pharyngeal taste organ of a blood-feeding insect functions in food recognition.

BACKGROUND: Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survival from the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingested food. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissing bug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, comprises eight taste sensilla that become bathed with the incoming blood. RESULTS: We showed that these taste sensilla house gustatory receptor neurons projecting their axons through the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electrically activated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP, and caffeine. Using RNA-Seq, we examined the expression of sensory-related gene families in the PO. We identified gustatory receptors, ionotropic receptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors, neuropeptide receptors, and biogenic amine receptors. RNA interference assays demonstrated that the salt-related pickpocket channel Rproppk014276 is required during feeding of an appetitive solution of NaCl and ATP. CONCLUSIONS: We provide evidence of the role of the pharyngeal organ in food evaluation. This work shows a comprehensive characterization of a pharyngeal taste organ in a hematophagous insect.

Molecular and functional basis of high-salt avoidance in a blood-sucking insect.

Salts are essential nutrients required for many physiological processes, and accordingly, their composition and concentration are tightly regulated. Taste is the ultimate sensory modality involved in resource quality assessment, resulting in acceptance or rejection. Here we found that high salt concentrations elicit feeding avoidance in the blood-sucking bug Rhodnius prolixus and elucidate the molecular and neurophysiological mechanisms involved. We found that high-salt avoidance is mediated by a salt-sensitive antennal gustatory receptor neuron (GRN). Using RNAi, we demonstrate that this process requires two amiloride-sensitive pickpocket channels (PPKs; Rpro PPK014276 and Rpro PPK28) expressed within these cells. We found that antennal GRNs project to the insect primary olfactory center, the antennal lobes, revealing these centers as potential sites for the integration of taste and olfactory host-derived cues. Moreover, the identification of the gustatory basis of high-salt detection in a hematophagous insect suggests novel targets for the prevention of biting and feeding.

CAPPRIC Study-Characterization of Community-Acquired Pneumonia in Spanish Adults Managed in Primary Care Settings.

The real burden of community-acquired pneumonia (CAP) in non-hospitalized patients is largely unknown. This is a 3-year prospective, observational study of ambulatory CAP in adults, conducted in 24 Spanish primary care centers between 2016-2019. Sociodemographic and clinical variables of patients with radiographically confirmed CAP were collected. Pneumococcal etiology was assessed using the Binax Now® test. Patients were followed up for 10 ± 3 days. A total of 456 CAP patients were included in the study. Mean age was 56.6 (±17.5) years, 53.5% were female, and 53.9% had ≥1 comorbidity. Average incidence of CAP was 1.2-3.5 cases per 1000 persons per year. Eighteen patients (3.9%) were classified as pneumococcal CAP. Cough was present in 88.1% of patients at diagnosis and fever in 70.8%. Increased pulmonary density (63.3%) and alveolar infiltrates with air bronchogram (16.6%) were the most common radiographic findings. After 14.6 ± 6.0 days (95% CI = 13.9-15.3), 65.4% of patients had recovered. Hospitalization rate was 2.8%. The most frequently prescribed antibiotics were quinolones (58.7%) and ß-lactams (31.1%). In conclusion, one-third of CAP patients did not fully recover after two weeks of empiric antibiotic therapy and 2.8% required hospitalization, highlighting the significant burden associated with non-hospitalized CAP in Spain.

Sensory discrimination between aversive salty and bitter tastes in an haematophagous insect.

Sensory aversion is essential for avoiding prospective dangers. We studied the chemical perception of aversive compounds of different gustatory modalities (salty, bitter) in the haematophagous bug, Rhodnius prolixus. Over a walking arena, insects avoided a substrate embedded with 1M NaCl or KCl if provided with water as an alternative. However, no preferences were expressed when both salts were opposed to each other. A pre-exposure to amiloride interfered with the repellency of NaCl and KCl equally, suggesting that amiloride-sensitive receptors are involved in the detection of both salts. Discriminative experiments were then performed to determine whether R. prolixus can distinguish between these salts. An aversive operant conditioning involving either NaCl or KCl modulated the repellency of the conditioned salt, but also of the novel salt. Repellency levels of both salts were rigid to a chemical pre-exposure to any of both salts. When gustatory modalities were crossed by presenting as a choice NaCl and a bitter molecule as caffeine (Caf), no innate preferences were expressed. Aversive operant conditionings with either NaCl or Caf rendered unspecific changes in the repellency of both compounds. A chemical pre-exposure to Caf modulated the response to Caf but not to NaCl, suggesting the existence of two independent neural pathways for the detection of salts and bitter compounds. Overall results suggest that R. prolixus cannot discriminate molecules of the same gustatory modality (i.e. salty), but can distinguish between salty and bitter tastes. The potential use of aversive gustatory stimuli as a complement of commercially available olfactory repellents is discussed.

Impact of a structured HIV testing program in a hospital emergency department and a primary care center.

INTRODUCTION: HIV testing guidelines are poorly implemented in most clinical settings. The best screening strategy and healthcare scenario are still unknown. The aim of our study is to evaluate the impact of a structured HIV testing intervention (DRIVE), compared to HIV testing as routinely performed in clinical practice, in two different clinical settings: a primary care center and an emergency department. METHODS: Prospective evaluation of an HIV testing strategy in two clinical settings from the same healthcare area. The DRIVE program included trained nurse practitioners to perform the screening, a questionnaire to assess the risk of exposure and HIV indicator conditions (RE&IC), and rapid HIV tests. The main variables between the DRIVE program and clinical practice were the absolute number of newly diagnosed HIV infections and testing coverage. RESULTS: The DRIVE program included 5,329 participants, of which 51.2% reported at least one positive answer in the questionnaire. The estimated HIV testing coverage was significantly higher in the DRIVE program than in the routine clinical practice (7.17% vs. 0.96%, p < 0.001), and was better in the primary care center than in the emergency department with the two strategies. Twenty-two HIV-positive people were identified, with a rate of 8.6‰ in the emergency department vs. 2.2‰ in the primary care center (p = 0.001). A higher rate of new HIV diagnoses was found in the DRIVE program compared to routine clinical practice (29.6 vs. 3.1 per 100,000 patients attended; p < 0.001). CONCLUSIONS: An easy-to-implement, structured intervention increased the absolute number of new HIV diagnoses and HIV tests, compared to routine clinical practice.

Learning Spatial Aversion Is Sensory-Specific in the Hematophagous Insect Rhodnius prolixus.

Even though innate behaviors are essential for assuring quick responses to expected stimuli, experience-dependent behavioral plasticity confers an advantage when unexpected conditions arise. As being rigidly responsive to too many stimuli can be biologically expensive, adapting preferences to time-dependent relevant environmental conditions provide a cheaper and wider behavioral reactivity. According to their specific life habits, animals prioritize different sensory modalities to maximize environment exploitation. Besides, when mediating learning processes, the salience of a stimulus usually plays a relevant role in determining the intensity of an association. Then, sensory prioritization might reflect an heterogeneity in the cognitive abilities of an individual. Here, we analyze in the kissing bug Rhodnius prolixus if stimuli from different sensory modalities generate different cognitive capacities under an operant aversive paradigm. In a 2-choice walking arena, by registering the spatial distribution of insects over an experimental arena, we evaluated firstly the innate responses of bugs confronted to mechanical (rough substrate), visual (green light), thermal (32°C heated plate), hygric (humidified substrate), gustatory (sodium chloride), and olfactory (isobutyric acid) stimuli. In further experimental series bugs were submitted to an aversive operant conditioning by pairing each stimulus with a negative reinforcement. Subsequent tests allowed us to analyze if the innate behaviors were modulated by such previous aversive experience. In our experimental setup mechanical and visual stimuli were neutral, the thermal cue was attractive, and the hygric, gustatory and olfactory ones were innately aversive. After the aversive conditioning, responses to the mechanical, the visual, the hygric and the gustatory stimuli were modulated while responses to the thermal and the olfactory stimuli remained rigid. We present evidences that the spatial learning capacities of R. prolixus are dependent on the sensory modality of the conditioned stimulus, regardless their innate valence (i.e., neutral, attractive, or aversive). These differences might be given by the biological relevance of the stimuli and/or by evolutionary aspects of the life traits of this hematophagous insect.

Nitric oxide contributes to high-salt perception in a blood-sucking insect model.

In all organisms, salts produce either appetitive or aversive responses depending on the concentration. While low-salt concentration in food elicits positive responses to ingest, high-salt triggers aversion. Still the mechanisms involved in this dual behavior have just started to be uncovered in some organisms. In Rhodnius prolixus, using pharmacological and behavioral assays, we demonstrated that upon high-salt detection in food a nitric oxide (NO) dependent cascade is activated. This activation involves a soluble guanylate cyclase (sGC) and the production of cyclic guanosine monophosphate (cGMP). Thus, appetitive responses to low-salt diets turn to aversion whenever this cascade is activated. Conversely, insects feed over aversive high-salt solutions when it is blocked by reducing NO levels or by affecting the sGC activity. The activation of NO/sGC/cGMP cascade commands the avoidance feeding behavior in R. prolixus. Investigations in other insect species should examine the possibility that high-salt aversion is mediated by NO/sSG/cGMP signaling.

Incremental cost per newly diagnosed HIV infection (NDHI): routine (RTS), targeted (TTS), and current clinical practice testing strategies (CPTS).

INTRODUCTION: Although RTS as HIV Diagnosis was considered cost effectiveness [1], overall budget may be unaffordable for some countries. We explore Incremental cost per NDHI associated with different TS. MATERIALS AND METHODS: From a health care perspective, using direct costs and Euros currency, we calculated budget and cost per NDHI of RTS (all patients were tested), TTS (Universal risk practices and clinical conditions-RP&CC - only positive were tested), and CPTS (Only patients physicians considered were tested). We considered DRIVE (Spanish acronym of HIV infection Rapid Diagnosis) study and clinical Practice outcomes. Population between 18-60 years, attending to a Hospital Emergency Room or to a Primary Care Center performed an HIV RP&CC questionnaire (Q) and an HIV rapid test (HIV RT). Unitary costs considered were: HIV RT, nurse, registry, transport and HIV confirmation when necessary, imputed to all population in RTS and CPTS and only in HIV RP&CC-Q positive in TTS analysis, while HIV RP&CC-Q costs were added to all population in TTS. Sensitivity analyses were performed with varying rates of NDHI and of positive HIV RP&CC-Q population, and different RP&CC Q sensitivity (SE) to predict HIV infection. RESULTS: 5,329 HIV RP&CC-Q and HIV RT were performed to 49.64% women, median age 37 years old, 74.9% Spaniards. In DRIVE and CP, NDHI were 4.1‰, and 1.6‰, while HIV RP&CC-Q was positive in 51.2%. HIV RP&CC-Q SE was 100%. Overall budget employed in HIV testing was in RTS 43,503€, in TTS 24,472€ and in CPTS 5,032€. Cost per 1 NDHI was 1,977€, 1,112€ and 5,032€, respectively. A reduction in cost of 865€, favouring TTS vs. RTS, while an increased cost of 824€ in CPTS vs. RTS was obtained. Considering NDHI rate of 2.6‰ saving costs increased to 1379€ in TTS, while were reduced to 576€ if NDHI rate increases 6.2‰. Effect of RP&CC-Q positivity rate was similar, if 25% saving costs were 1368€, while if 75% were reduced to 399€. Varying SE of RP&CC-Q to 95%, 91% and 50% cost saving was 810€, 754€, and 208€, and number of MHI one, two and 11. CONCLUSIONS: In DRIVE study Targeted TS with universal screening of RP&CC before an HIV rapid test is cost saving, without missing NDHI, with respect to Routine TS. Lower rates of HIV infection and RP&CC in the population, increase costs savings.

Activación del sistema de los opiodes endógenos por dosis subconvulsivamantes de metrazol / Activation of the endogenous opioid system with metrazol subconvulsivant dosis

Se investigaron las alteraciones en el sistema de los opioides endógenos en el cerebro de la rata, inducidas por la administración de una dósis subconvulsivante de metrazol (PTZ) (30 mg/kg i.p.). Por medio de experimentos de microdiálisis, encontramos durante los primeros 60 min después del tratamiento, una liberación importante de opiodes endógenos en el hipocampo y la amígdala cerebral. Posteriormente, los valores regresaron a los niveles basales. Por autorradiografía se observó un decremento en los niveles de los receptores mu en varias estructuras cerebrales. Mediante el análisis de la unión a receptores las membranas cerebrales, se confirmó un decremento en el número de estos receptores, sin cambios en su afinidad. En la aplicación de la prueba de Randall-Sellito, se encontró un aumento en el umbral de respuesta a estímulos dolorosos, durante los primeros 30 min. después del PTZ. Finalmente, experimentos de hibridación in situ revelaron un incremento en los niveles de la proencefalina a las 24 hrs después del tratamiento. Nuestros resultados indican que la administración de dosis subconvulsivante de PTZ activan de manera importante al sistema de los opiodes endógenos. Estos cambios resultan relevantes para entender el proceso del epileptogénesis y los mecanismos involucrados en el mismo