ABSTRACT
Species diversity of the Bifidobacterium genus was scarcely explored in different rearing systems of poultry. The aim of the study was to isolate intestinal species and compare their physiological and traits for adaptation to the avian intestinal niche. Fourteen strains isolated from chickens of intensive rearing farms and free-range hens, were identified by 16S rDNA sequencing, rep-PCR fingerprinting, and carbohydrates fermentation. Strains belonged to species Bifidobacterium pseudolongum subsp. pseudolongum and subsp. globosum, B. pullorum, B. animalis subsp lactis, B. boum, B. thermacidophilum subsp. thermacidophilum and B. thermophilum. One strain of B. animalis and B. pullorum, and two of B. pseudolongum subsp. pseudolongum were obtained from chicks, while the others were from free-range adult hens. Growth (in MRSc) at the poultry physiological temperature, acids production in caecal water with raffinose (rCW), ex vivo adhesion (%) to avian intestinal epithelial cells (IEC), and auto-aggregation (%) were used for discrimination inter- and intra-specific. Significantly different acetic and lactic acids production and growth temperatures were observed in strains of the same species/subspecies. Remarkable auto-aggregation capability was observed in B. thermacidophilum subsp. thermacidophilum LET 406 (40.2 ± 1.1%), while adhesion property was highlighted in B. pseudolongum subsp. pseudolongum LET 408 (65.30 ± 4.75% in jejunum; 46.05 ± 2.80 in ileum). Scanning Electronic Microscopy of the interaction IEC-LET 408 revealed an irregular bacterial surface exhibiting vesicle-like arrangements and filaments that formed a network among bacteria cells and with the epithelial cells, as possible adaptative response to promote its persistence in the gut. These finds will be valuable for bacterial supplements design intended to intensive rearing.
Subject(s)
Chickens , Probiotics , Animals , Female , Bifidobacterium , DNA, Ribosomal/geneticsABSTRACT
BACKGROUND: Two out of three wrist fractures seen in an emergency department are displaced but most can be treated conservatively after closed reduction. Patient-reported pain during closed reduction of distal radius fractures varies widely and the best method to decrease the perceived pain has not been well established. The purpose of this study was to assess pain during closed reduction of distal radius fractures after using haematoma block as method of anaesthesia. PATIENTS AND METHODS: Cross-sectional clinical study including all patients who presented an acute fracture of the distal radius requiring closed reduction and immobilisation during a six-month period in two University Hospitals. Demographic data, fracture classification, perceived pain using a visual analogue scale at different times of reduction and complications were registered. RESULTS: Ninety-four consecutive patients were included. Mean age was 61 years. Mean pain score at initial assessment was 6 points. After the haematoma block, the perceived pain during the reduction manoeuvre improved to 5.1 points at the wrist, but increased to 7.3 points at the fingers. Pain decreased to 4.9 points during cast placement and reached 1.4 point after sling placement. The reported pain was higher in women at all times. There were no significant differences according to the according to the type of fracture. No neurological or skin complications were observed. CONCLUSIONS: Haematoma block is only a mildly effective method to reduce wrist pain during closed reduction of distal radius fractures. This technique slightly decreases the perceived pain in the wrist and does not reduce the pain in the fingers. Other reduction methods or other analgesic techniques may be more effective options. LEVEL OF EVIDENCE: Therapeutic study. Cross-sectional study - Level IV.
ABSTRACT
OBJECTIVE: To assess the ability of optic nerve head (ONH) parameters, peripapillary retinal nerve fiber layer (pRNFL), and macular ganglion cell layer (GCL) thickness measurements with swept-source optical coherence tomography (SS-OCT), to discriminate between glaucomatous and non-glaucomatous optic neuropathy (GON and NGON). METHODS: This retrospective cross-sectional study involved 189 eyes of 189 patients, 133 with GON and 56 with NGON. The NGON group included ischemic optic neuropathy, previous optic neuritis, and compressive, toxic-nutritional, and traumatic optic neuropathy. Bivariate analyses of SS-OCT pRNFL and GCL thickness and ONH parameters were performed. Multivariable logistic regression analysis was employed to obtain predictor variables from OCT values, and the area under the receiver operating characteristic curve (AUROC) was calculated to differentiate between NGON and GON. RESULTS: Bivariate analyses showed that the overall and inferior quadrant of the pNRFL was thinner in the GON group (P=0.044 and P<0.01), while patients with NGON had thinner temporal quadrants (P=0.044). Significant differences between the GON and NGON groups were identified in almost all the ONH topographic parameters. Patients with NGON had thinner superior GCL (P=0.015), but there were no significant differences in GCL overall and inferior thickness. Multivariate logistic regression analysis demonstrated that vertical cup-to-disc ratio (CDR), cup volume, and superior GCL provided independent predictive value for differentiating GON from NGON. The predictive model of these variables along with disc area and age achieved an AUROC=0.944 (95% CI 0.898-0.991). CONCLUSIONS: SS-OCT is useful in discriminating GON from NGON. Vertical CDR, cup volume, and superior GCL thickness show the highest predictive value.
Subject(s)
Glaucoma , Optic Nerve Diseases , Humans , Tomography, Optical Coherence , Retrospective Studies , Cross-Sectional Studies , Retinal Ganglion Cells , Glaucoma/complications , Glaucoma/diagnosis , Optic Nerve Diseases/diagnostic imaging , ROC Curve , Intraocular PressureABSTRACT
BACKGROUND: Two out of three wrist fractures seen in the emergency are displaced but most can be treated conservatively after closed reduction. Patient-reported pain during closed reduction of distal radius fractures varies widely and the best method to decrease the perceived pain has not been well established. The purpose of this study was to assess the pain during closed reduction of distal radius fractures after using the hematoma block as method of anaesthesia. PATIENTS AND METHODS: Cross-sectional clinical study including all patients who presented an acute fracture of the distal radius requiring closed reduction and immobilization during a six-month period in two University Hospitals. Demographic data, fracture classification, perceived pain using a visual analog scale at different times of reduction and complications were registered. RESULTS: Ninety-four consecutive patients were included. Mean age was 61 years. Mean pain score at initial assessment was 6 points. After the hematoma block, the perceived pain during the reduction manoeuvre improved to 5.1 points at the wrist, but increased to 7.3 points at the fingers. Pain decreased to 4.9 points during cast placement and reached 1.4 point after sling placement. The reported pain was higher in women at all times. There were no significant differences according to the according to the type of fracture. No neurological or skin complications were observed. CONCLUSIONS: The hematoma block is only a mild effective method to reduce the wrist pain during closed reduction of distal radius fractures. This technique decreases slightly the perceived pain in the wrist and does not reduce the pain in the fingers. Other reduction methods or other analgesic techniques may be more effective options. LEVEL OF EVIDENCE: Therapeutic study. Cross-sectional study - Level IV.
ABSTRACT
BACKGROUND: Historical reconstructions within Podocarpaceae have provided valuable information to disentangle biogeographic scenarios that begun 65 Mya. However, early molecular phylogenies of Podocarpaceae failed to agree on the intergeneric relationships within the family. The aims of this study were to test whether plastome organization is stable within the genus Podocarpus, to estimate the selective regimes affecting plastome protein-coding genes, and to strengthen our understanding of the phylogenetic relationships and biogeographic history. METHODS AND RESULTS: We sequenced the plastomes of four South American species from Patagonia, southern Yungas, and Brazilian subtropical forests. We compared their plastomes to those published from Brazil, Africa, New Zealand, and Southeast Asia, along with representatives from other genera within Podocarpaceae as outgroups. The four newly sequenced plastomes ranged in size between 133,791 bp and 133,991 bp. Gene content and order among chloroplasts from South American, African and Asian Podocarpus were conserved and different from the plastome of P. totara, from New Zealand. Most genes showed substitution patterns consistent with a conservative selective regime. Phylogenies inferred from either complete sequences or protein coding regions were mostly congruent with previous studies, but showed earlier branching of P. salignus, P. totara and P. sellowii. CONCLUSIONS: Highly similar and conserved plastomes of African, South American and Asian species suggest that P. totara plastome should be revised and compared to other species from Oceanic distribution. Furthermore, given such structural conservation, we suggest plastome sequencing is not useful to test whether genomic order can be climatically or geologically structured.
Subject(s)
Chloroplasts , Genomics , Phylogeny , Base Sequence , BrazilABSTRACT
BACKGROUND: Macular hemorrhages are a severe complication of other retinal pathologies, such as age-related macular degeneration (AMD) or macroaneurysms. Their therapeutic approach is not standardized, and can vary from observation to surgical treatment. MATERIAL AND METHODS: Retrospective analysis of 22 cases of macular hemorrhage, treated with vitrectomy associated to subretinal rTPA and intravitreal anti-VEGF over a period of 5 years. RESULTS: 22 eyes of 22 patients were included, of which 12 (52%) were women. The mean age at diagnosis was 84.4 years. 13 patients were pseudophakic (54.1%) and 19 (86.36%) had previous ophthalmological comorbidities. The etiology of the macular hemorrhage was AMD in 19 patients (86.36%). The mean of best VA corrected at diagnosis was 24.55 (Early Treatment Diabetic Retinopathy Study score -ETDRS), with a statistically significant improvement to 36.78 3 months after surgery (p = 0.011). With an average of 23.5 months of follow-up, no differences in prognosis associated with the etiology or size of the hemorrhage were observed. CONCLUSION: The treatment of macular hemorrhages by vitrectomy, subretinal rTPA and antiVEGF improves the visual prognosis of affected patients.
Subject(s)
Retinal Hemorrhage , Tissue Plasminogen Activator , Vascular Endothelial Growth Factors , Vitrectomy , Female , Humans , Intravitreal Injections , Macular Degeneration/complications , Macular Degeneration/drug therapy , Male , Retinal Hemorrhage/drug therapy , Retinal Hemorrhage/etiology , Retinal Hemorrhage/surgery , Retrospective Studies , Tissue Plasminogen Activator/therapeutic use , Vascular Endothelial Growth Factors/therapeutic use , Visual AcuityABSTRACT
BACKGROUND: To assess the benefit of macular spectral-domain optical coherence tomography (SD-OCT) as a part of the routinary preoperative study of patients undergoing cataract surgery. METHODS: A prospective single-center study study was performed. Consecutive patients with normal biomicroscopic funduscopy, moderate cataract and no history of ophthalmological pathologies were enrolled. All patients underwent macular SD-OCT. The obtained images were analysed by a general ophthalmologist and two retina specialists. Incidence of macular pathology and its relation to age and comorbidities were assessed. RESULTS: Eight-hundred and thirty-six eyes of 419 patients were enrolled in this study. All images were analysed telematically by a general ophthalmologist. Forty-nine eyes were excluded due to insufficient quality of the obtained images. Abnormal images were observed in 156 eyes (18.6%), including age-related macular degeneration in 68 (8.2%), epiretinal membrane (ERM) in 67 (8.0%), cystoid macular edema in 3 eyes (0.4%), among others. Diagnostics with severe impact on patient visual prognosis were observed in 16 eyes (3.82%) from 12 patients. The relationship between incidence of macular pathologies and age or comorbidities was not statistically significant. To assess accuracy of the first observer, images were subsequently analysed by two retinologists. The kappa index of concordance was 0.80 and 0.85. CONCLUSIONS: Implementing a systematic macular SD-OCT as a preoperative test prior to cataract surgery would improve quality of postoperative visual prognosis information. A general ophthalmologist would be suitable to screen for pathology through macular OCT images.
Subject(s)
Cataract Extraction , Cataract , Epiretinal Membrane , Cataract/diagnosis , Epiretinal Membrane/diagnosis , Humans , Prospective Studies , Tomography, Optical Coherence/methodsABSTRACT
The main aim of this international consensus document on obstructive sleep apnea is to provide guidelines based on a critical analysis of the latest literature to help health professionals make the best decisions in the care of adult patients with this disease. The expert working group was formed primarily of 17 scientific societies and 56 specialists from a wide geographical area (including the participation of 4 international societies), an expert in methodology, and a documentalist from the Iberoamerican Cochrane Center. The document consists of a main section containing the most significant innovations and a series of online manuscripts that report the systematic literature searches performed for each section of the international consensus document. This document does not discuss pediatric patients or the management of patients receiving chronic non-invasive mechanical ventilation (these topics will be addressed in separate consensus documents).
ABSTRACT
PURPOSE: The goal of this article is to present an infrequent clinical case and to review the available literatura, with an emphasis on ophthalmological symptoms. METHODS: We present the case of a 4-year-old girl with a large dentigerous cyst on the maxillary bone, who had long-standing unilateral epiphora associated with progressive ocular dystopia, facial asymmetry and ipsilateral amblyopia. A multidisciplinary approach was taken by the maxillofacial surgery, ophthalmology and optometry teams. This included systemic antibiotic administration, surgical cyst drainage and amblyopia treatment. The literature review was carried out in the MEDLINE database through the free electronic access to PubMed in March 2020. RESULTS: At the 6-month follow-up, the patient was asymptomatic. The most common symptoms of dentigerous cysts are epiphora 36.8%, ocular dystopia 31.2%, diplopia 21.1%, proptosis, nasolacrimal duct obstruction and blurred vision at 10.5%. Amblyopia has not been reported. CONCLUSIONS: Dentigerous cysts are benign odontogenic cysts, which can be found in the jaw and less frequently on the maxillary bone. They are usually asymptomatic, and the occurrence of ophthalmic complications is very infrequent. Multidisciplinary management is essential to avoiding long-term morbidity of maxillary dentigerous cysts and should include an ophthalmologist.
Subject(s)
Amblyopia , Dentigerous Cyst , Lacrimal Duct Obstruction , Maxillary Diseases , Nasolacrimal Duct , Amblyopia/complications , Amblyopia/diagnosis , Child, Preschool , Dentigerous Cyst/complications , Dentigerous Cyst/diagnosis , Female , HumansABSTRACT
Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.
Subject(s)
Noninvasive Ventilation , Respiratory Insufficiency , Adult , Cannula , Child , Consensus , Humans , Infant, Newborn , Oxygen , Pyruvates , Respiratory Insufficiency/therapy , Societies, ScientificABSTRACT
Philornis Meinert 1890 (Diptera: Muscidae) is a genus of flies that parasitize birds in the Neotropical region. The characteristics of the host-parasite interactions and its consequences may depend on the Philornis species involved, and thus precise identification of these parasites is crucial for the interpretation of ecological and epidemiological studies. However, morphological identification of Argentine Philornis species is elusive while molecular evidence points towards the existence of a complex of cryptic species or lineages undergoing a speciation process, which were named the 'Philornis torquans complex'. Herein the authors extended the current knowledge on the systematics and biogeography of parasitic Philornis flies from Argentina, analysing samples collected in several ecoregions, including the Atlantic Forest, Iberá Wetlands, Open Fields and Grasslands, Espinal, Pampa, Dry Chaco, Humid Chaco, Delta and Paraná River Islands, Monte of Plains and Plateaus. The results of the present study strengthen the evidence on previously described Philornis genotypes using four genetic markers (ITS2, COI, ND6, 12S rRNA). The authors report new patterns of occurrence and describe the presence of a novel genotype of subcutaneous Philornis. In addition, the present study unveils ecological niche differences among genotypes of the Philornis torquans complex in southern South America.
Subject(s)
Muscidae , Parasites , Animals , Argentina/epidemiology , Genetic Variation , Larva , Muscidae/geneticsABSTRACT
BACKGROUND: The optimal interface for the delivery of home non-invasive ventilation (NIV) to treat chronic respiratory failure has not yet been determined. The aim of this individual participant data (IPD) meta-analysis was to compare the effect of nasal and oronasal masks on treatment efficacy and adherence in patients with COPD and obesity hypoventilation syndrome (OHS). METHODS: We searched Medline and Cochrane Central Register of Controlled Trials for prospective randomised controlled trials (RCTs) of at least 1 month's duration, published between January 1994 and April 2019, that assessed NIV efficacy in patients with OHS and COPD. The main outcomes were diurnal PaCO2, PaO2 and NIV adherence (PROSPERO CRD42019132398). FINDINGS: Of 1576 articles identified, 34 RCTs met the inclusion criteria and IPD were obtained for 18. Ten RCTs were excluded because only one type of mask was used, or mask data were missing. Data from 8 RCTs, including 290 IPD, underwent meta-analysis. Oronasal masks were used in 86% of cases. There were no differences between oronasal and nasal masks for PaCO2 (0.61 mm Hg (95% CI -2.15 to 3.38); p=0.68), PaO2 (-0.00 mm Hg (95% CI -4.59 to 4.58); p=1) or NIV adherence (0·29 hour/day (95% CI -0.74 to 1.32); p=0.58). There was no interaction between the underlying pathology and the effect of mask type on any outcome. INTERPRETATION: Oronasal masks are the most used interface for the delivery of home NIV in patients with OHS and COPD; however, there is no difference in the efficacy or tolerance of oronasal or nasal masks.
Subject(s)
Noninvasive Ventilation , Respiratory Insufficiency , Humans , Hypercapnia , Masks , Respiration, Artificial , Respiratory Insufficiency/therapyABSTRACT
Resting state functional connectivity research has shown that general cognitive ability (GCA) is associated with brain resilience to targeted and random attacks (TAs and RAs). However, it remains to be seen if the finding generalizes to structural connectivity. Furthermore, individuals showing performance levels at the very high area of the GCA distribution have not yet been analyzed in this regard. Here we study the relation between TAs and RAs to structural brain networks and GCA. Structural and diffusion-weighted MRI brain images were collected from 189 participants: 60 high cognitive ability (HCA) and 129 average cognitive ability (ACA) individuals. All participants completed a standardized fluid reasoning ability test and the results revealed an average HCA-ACA difference equivalent to 33 IQ points. Automated parcellation of cortical and subcortical nodes was combined with tractography to achieve an 82 × 82 connectivity matrix for each subject. Graph metrics were derived from the structural connectivity matrices. A simulation approach was used to evaluate the effects of recursively removing nodes according to their network centrality (TAs) versus eliminating nodes at random (RAs). HCA individuals showed greater network integrity at baseline and prior to network collapse than ACA individuals. These effects were more evident for TAs than RAs. The networks of HCA individuals were less degraded by the removal of nodes corresponding to more complex information processing stages of the PFIT network, and from removing nodes with larger empirically observed centrality values. Analyzed network features suggest quantitative instead of qualitative differences at different levels of the cognitive ability distribution.
Subject(s)
Brain/physiopathology , Cognition/physiology , Nerve Net/physiopathology , Neural Pathways/physiopathology , Connectome/methods , Diffusion Magnetic Resonance Imaging/methods , Female , Humans , Male , Models, Neurological , Problem Solving , Rest/physiologyABSTRACT
Philornis flies are the major cause of myiasis in nestlings of Neotropical birds, being of major concern in geographically-restricted and endangered bird species. Despite its relevance for the conservation of birds, there is little information about the environmental dimensions determining Philornis spp. geographical range. By using maximum entropy, we identified for the first time the macro-environmental variables constraining the abiotic niche of the P. torquans complex in South America, and provided a model map of its potential distribution based on environmental suitability. We identified the minimum temperature of the coldest month as the most relevant variable, associated with the largest decrease in habitat suitability in Brazil and northern South America. Furthermore, the mean temperature of the warmest quarter limited suitability mostly along with the Andean range. In addition, humidity and moisture are influential factors in most of Argentina, northern Chile, and coastal Peru. The geographical projection suggests that environments in most of central-eastern Argentina, and in a broad area in central Chile, are suitable for the presence of the P. torquans complex. Besides providing information about the ecology of Philornis spp., this study represents a tool for bird conservation and a reference for future work on the distribution of this genus.
Subject(s)
Muscidae , Myiasis , Parasites , Animals , Birds , Chile/epidemiology , Myiasis/veterinaryABSTRACT
Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.
Subject(s)
Cysts/diagnosis , Iris Diseases/diagnosis , Iris/pathology , Child , Cysts/diagnostic imaging , Cysts/pathology , Eye Abnormalities/diagnosis , Eye Abnormalities/diagnostic imaging , Eye Abnormalities/pathology , Flocculation , Humans , Iris/chemistry , Iris/diagnostic imaging , Iris Diseases/diagnostic imaging , Iris Diseases/pathology , Male , Slit Lamp MicroscopyABSTRACT
BACKGROUND: Obesity hypoventilation syndrome (OHS) is treated with either non-invasive ventilation (NIV) or CPAP, but there are no long-term cost-effectiveness studies comparing the two treatment modalities. OBJECTIVES: We performed a large, multicentre, randomised, open-label controlled study to determine the comparative long-term cost and effectiveness of NIV versus CPAP in patients with OHS with severe obstructive sleep apnoea (OSA) using hospitalisation days as the primary outcome measure. METHODS: Hospital resource utilisation and within trial costs were evaluated against the difference in effectiveness based on the primary outcome (hospitalisation days/year, transformed and non-transformed in monetary term). Costs and effectiveness were estimated from a log-normal distribution using a Bayesian approach. A secondary analysis by adherence subgroups was performed. RESULTS: In total, 363 patients were selected, 215 were randomised and 202 were available for the analysis. The median (IQR) follow-up was 3.01 (2.91-3.14) years for NIV group and 3.00 (2.92-3.17) years for CPAP. The mean (SD) Bayesian estimated hospital days was 2.13 (0.73) for CPAP and 1.89 (0.78) for NIV. The mean (SD) Bayesian estimated cost per patient/year in the NIV arm, excluding hospitalisation costs, was 2075.98 (91.6), which was higher than the cost in the CPAP arm of 1219.06 (52.3); mean difference 857.6 (105.5). CPAP was more cost-effective than NIV (99.5% probability) because longer hospital stay in the CPAP arm was compensated for by its lower costs. Similar findings were observed in the high and low adherence subgroups. CONCLUSION: CPAP is more cost-effective than NIV; therefore, CPAP should be the preferred treatment for patients with OHS with severe OSA. TRIAL REGISTRATION NUMBER: NCT01405976.
Subject(s)
Continuous Positive Airway Pressure/economics , Cost-Benefit Analysis , Obesity Hypoventilation Syndrome/therapy , Aged , Bayes Theorem , Female , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Noninvasive Ventilation , Obesity Hypoventilation Syndrome/physiopathology , Polysomnography , Severity of Illness Index , Spain , SpirometryABSTRACT
The tropical fowl mite, Ornithonyssus bursa, is a common avian parasite found on diverse bird species worldwide. In the Neotropical region, O. bursa is present in wild birds, but it may also infect poultry and bite humans. Little is known about the ecology and epidemiology of this parasite. We conducted a thorough longitudinal study in passerine assemblages from central Argentina, gathering data from six reproductive seasons, with the aim of identifying factors that have a role in driving the occurrence and distribution of O. bursa in its natural hosts. We focused on the brood and microhabitat levels, accounting for potential confounders of higher levels. The results hereby presented contribute to our knowledge on the eco-epidemiology of O. bursa in natural hosts of the Neotropical region. Among the many variables assessed, nest material and host species appeared to be the most important correlates of O. bursa prevalence. Nonetheless, supplementary analyses showed that host species is a stronger predictor than nest material. Moreover, mite burden (parasite intensity) was found to depend on host species, but not on nest material. The association with species depended on nestling age, suggesting that resistance builds up as the nestling develop, but at a different pace depending on the bird species. Brood size was inversely correlated with intensity of parasitism, suggesting a dilution of the parasite burden on each nestling.