Improving the ability to discriminate medical multiple-choice questions through the analysis of the competitive examination to assign residency positions in Spain.

INTRODUCTION: Psychometrics plays a vital role in evaluating educational research, including the analysis of multiple-choice exams. This study aims to improve the discriminatory ability of the "Médico Interno Residente" (MIR) medical exam in Spain, used to rank candidates for specialized healthcare training, through psychometric analysis. METHODS: We analyzed 2,890 MIR exam questions from 2009 to 2021 (totaling 147,214 exams), categorizing them based on methodology and response type. Evaluation employed classical test theory and item response theory (IRT). Classical test theory determined difficulty and discrimination indices, while IRT assessed the relationship between knowledge levels and question performance. RESULTS: Question distribution varied across categories and years. Frequently addressed knowledge areas included various medical specialties. Non-image-associated clinical cases were the easiest, while case-based clinical questions exhibited the highest discriminatory capacity, differing significantly from image-based case or negative questions. High-quality questions without images had longer stems but shorter answer choices. Adding images reduced discriminatory power and question difficulty, with image-based questions being easier. Clinical cases with images had shorter stems and longer answer choices. CONCLUSIONS: For improved exam performance, we recommend using a clinical case format followed by direct short-answer questions. Questions should be of low difficulty, providing clear and specific answers based on scientific evidence and avoiding ambiguity. Typical clinical cases with key characteristic features should be presented, excluding uncertain boundaries of medical knowledge. Questions should have lengthy stems and concise answer choices, minimizing speculation. If images are used, they should be typical, clear, consistent with the exam, and presented within clinical cases using clinical semiotics and propaedeutics.

Changes in the national prevalence of asthma and coronavirus disease 2019 fatality: A population-based cross-sectional study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) mitigation and containment strategies implemented by each country can influence the prevalence of asthma and its fatality. OBJECTIVE: To analyze the trend of asthma prevalence and COVID-19 fatality in children and adults with asthma. METHODS: The prevalence of asthma and fatalities were compared among the peaks of 5 pandemic waves in Mexico. RESULTS: Among patients with COVID-19, the prevalence rates of asthma among children were as follows: wave I, 3.5%; wave II, 2.6%; wave III, 2.2%; wave IV, 2.4%; and wave V, 1.9% (P for trend < .001); the prevalence rates of asthma among adults were as follows: wave I, 2.5%; wave II, 1.8%; wave III, 1.5%; wave IV, 1.7%; and wave V, 1.6% (P for trend < .001). The rates of fatality because of COVID-19 among individuals with asthma were as follows: wave I, 8.9%; wave II, 7.7%; wave III, 5.0%; wave IV, 0.9%; and wave V, 0.2% (P for trend < .001). CONCLUSION: The prevalence rates of asthma and fatalities from COVID-19 suggest a gradual reduction throughout the pandemic in Mexico.

Asthma is not a risk factor for severity of SARS-CoV-2 infection in the Mexican population.

OBJECTIVE: This study aims to assess the association between asthma and severity of COVID-19 in the Mexican population. METHODS: The data from a national database of confirmed patients diagnosed with COVID-19, who attended from February to June 2020, were analyzed in a retrospective cohort study. Patients with and without asthma were compared concerning hospitalization, pneumonia, endotracheal intubation, and death related to COVID-19. Other covariates (age, sex, indigenous group, and comorbidity) were included in various logistic regression models. RESULTS: Asthma was associated with a lower risk of hospitalization (OR = 0.71, 95% CI 0.66 to 0.76), lower risk of pneumonia (OR = 0.75, 95% CI 0.69 to 0.81), and lower risk of endotracheal intubation (OR = 0.79, 95% CI 0.63 to 0.98). In addition, asthma decreased the risk of death from COVID-19 (OR = 0.73, 95% CI 0.65 to 0.82). In a subgroup analysis, the same association was observed in patients who required hospitalization (OR = 0.79, 95% CI 0.69 to 0.90), while in non-hospitalized patients, associations were inconsistent according to the covariates introduced in the models. There was no association between asthma and death in patients admitted to the intensive care unit (ICU), however, asthma significantly reduced the risk of death in the hospitalized patients who did not require ICU. CONCLUSION: Our results suggest that patients with asthma are less likely to require hospitalization, develop pneumonia, need tracheal intubation or die from COVID-19 as compared to patients without asthma.

Beyond eosinophilia: inflammatory patterns in patients with asthma.

Background: Recently, inflammatory cell ratios have gained importance as useful indicators in the categorization of asthma.Objective: We compared the concentration of white blood cells in peripheral blood, as well as their respective inflammatory cell ratios, between patients with asthma and a healthy control group.Methods: We performed cross-sectional analyses of the data obtained from 53 adult patients with asthma and 109 adult controls. In our study, we estimated and compared the following inflammatory cell ratios: Neutrophil-Lymphocyte Ratio (NLR), Eosinophil-Lymphocyte Ratio (ELR), Eosinophil-Neutrophil Ratio (ENR), Eosinophil-Monocyte Ratio (EMR), and Platelet-Lymphocyte Ratio (PLR). The magnitude of association was quantified with the odds ratio.Results: In both groups, the average age was 33 years. In asthmatic patients, we obtained the following results: eosinophils ≥ 400 cells/µl, accounted for 37.7%; basophils ≥ 110 cells/µl, comprised 37.7%; and monocytes < 320 cells/µl, reached 11.3%. In the control group, the results were as follows: 4.6%, 9.2% and 0.9%, respectively. When compared to the control group, asthmatic patients had higher odds of eosinophils ≥ 400 cells/µl (OR = 12.61, p < 0.0001); higher odds of basophils ≥ 110 cells/µl (OR = 6.00, p < 0.0001); and increased odds of monocytes < 320 cells/µl (OR = 13.79, p = 0.017). NLR did not differ between our two groups; however, ELR, ENR, EMR and PLR were significantly higher in the asthma group.Conclusions: Overall, patients with asthma have a higher concentration of eosinophils and basophils, fewer monocytes in their blood, and higher ratios of increased chronic inflammation.

Asthma and COVID-19 among healthcare workers from a Mexican Hospital: is there an association?

Background: Asthma does not appear to be a risk factor for developing COVID-19. Objective: The objective of the study was to analyze the role of asthma as a factor associated with COVID-19 among healthcare workers (HW). Methods: A crosssectional study was conducted in HW from a Mexican hospital. Data were obtained through an epidemiological survey that included age, sex, and history of COVID-19. Multivariate logistic regression analysis was performed to identify factors associated with COVID-19. Results: In total, 2295 HW were included (63.1% women; mean age 39.1 years); and 1550 (67.5%) were medical personnel. The prevalence of asthma in HW with COVID-19 was 8.3%; for the group without COVID-19, the prevalence was 5.3% (p = 0.011). The multivariate analyses suggested that asthma was associated with COVID-19 (OR 1.59, p = 0.007). Conclusion: Our study suggests that asthma could be a factor associated with COVID-19 in HW.

Oral Allergy Syndrome Associated with Jicama.

Background: The occurrence of oral symptoms after food consumption defines oral allergy syndrome (OAS). Thus, our objective was to report the association of oral allergy syndrome triggered by jicama. Methods: In this study, we report 10 cases of OAS associated with jicama eating. Results: Of the total cases, 6 were women; the mean age of the group was 28.3 ± 11.4 years. All patients suffered from allergic rhinitis and 3 of them also had asthma. On average, patients experienced the onset of symptoms 5 minutes after eating jicama. As expected, the patients had oral ailments, mainly itching in the pharynx, palate, and lips; furthermore, 4 out of 10 also had skin symptoms. The skin test by the prick-prick technique with fresh jicama had a mean diameter of 8.1 ± 5.4 mm. Conclusion: In closing, jicama should be considered as a cause of OAS, especially in regions where it is cultivated and eaten in large quantities.

Age Under 30 Years As a Predictor of Poor Survival in a Cohort of Mexican Women With Breast Cancer.

INTRODUCTION: Young women under 30 years with breast cancer (BC) are an emerging challenge. The purpose is to identify prognostic factors for survival in young women under 30 years of age with BC. MATERIAL AND METHODS: A retrospective cohort study was conducted among women younger than or equal to 40 years with BC and who were treated at the State Cancer Center during the period 2012-2017. Overall survival was assessed using the Kaplan-Meier method and the log-rank test. Univariate and multivariate analysis assessed survival predictors using Cox proportional hazards regression model. RESULTS: 282 young women were included. The >30-year-old subgroup showed a significant association with excess weight (P = .002) compared to the <30-year-old group. The <30-year-old subgroup showed a poor overall survival (56.7%), as well as highly significant values in advanced clinical stages, metastatic nodules, metastasis, and neoadjuvant therapy (P < .001). In Model 3 of the multivariate analysis, age <30 years (HR = 3.0; 95% CI 1.1 to 8.6), triple negative subtype (HR = 2.6; 95% CI 1.1 to 6.0), tumor size >5 cm HR = 2.3; 95% CI 1.03 to 5.1), and advanced clinical stages (HR = 6.6 95% CI 1.3 to 35.5) persisted as predictors. CONCLUSIONS: Being very young (<30 years) is a predictor for limited survival compared to the age of 30-40 years, as well as the tumor covariates for a worse prognosis: triple negative subtype, advanced stages, positive lymph nodes, and distant metastases in liver.

Anxiety and depression in adult patients with asthma: the role of asthma control, obesity and allergic sensitization.

OBJECTIVE: To determine the frequency of anxiety and depression in adult patients with asthma and to identify factors associated with them. METHODS: This cross-sectional study included 164 consecutively recruited patients with asthma aged ≥ 18 years. Participants were clinically assessed and the mental state was analyzed through of the Beck Anxiety Inventory (BAI), the Beck Depression Inventory II (BDI-II); the Asthma Control Test (ACT) was measured, and allergic sensitization and respiratory function were also evaluated. Binary logistic regression models to identify the factors related to anxiety or depression were carried out. Complementary, 95% confidence intervals (CI) were estimated. RESULTS: Anxiety was present in 54.3% of patients (95% CI: 46.6%-61.7%) while depression was found in 50.6% (95% CI: 43.0%-58.2%). Depression increased the odds of anxiety in patients with asthma (OR: 26.00, p < 0.0001), whereas an ACT score ≥ 20 points and allergic asthma were associated with a lower odds than the reference group (OR: 0.29; p = 0.007 and OR: 0.29; p = 0.024, respectively). Depression was associated with anxiety and obesity (OR: 25.33, p < 0.0001 and OR: 3.66; p = 0.014, respectively). CONCLUSIONS: Overall, more than half of all asthmatic patients suffer from anxiety and depression. Well-controlled asthma and allergic sensitization decreased the likelihood of anxiety, while depression was associated with both obesity and anxiety.

First description outside Europe of the emergent pathogen Vibrio europaeus in shellfish aquaculture.

Vibrio europaeus is an emergent pathogen affecting the most important bivalve species reared in Spanish and French hatcheries. Using a genomic approach, we identified V. europaeus outside Europe for the first time from massive larval mortalities of scallop (Argopecten purpuratus) in Chile and from seawater near a shellfish hatchery in the US West Coast. Results show the worldwide spreading and potential impact of V. europaeus for aquaculture; these four countries are among the 10 major producers of mollusks. Pathogenicity of V. europaeus was demonstrated for the first time towards scallop, the second most important species for Chilean mariculture.

Low prevalence of asthma in Mexican children and adults with a positive rtRT-PCR test for SARS-CoV-2: a cross-sectional study during the 2020 pandemic.

BACKGROUND: It has recently been argued that asthma does not increase the risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. If so, the prevalence of asthma in subjects diagnosed with COVID-19 should be lower than in the general population. OBJECTIVE: To determine the prevalence of asthma in Mexican children and adults with SARS-CoV-2 infection. METHODS: A public database of the Epidemiological Surveillance System for Viral Respiratory Disease in Mexico was analyzed. Those who underwent the real-time reverse transcriptase-polymerase chain reaction-SARS-CoV-2 (rtRT-PCR-SARS-CoV-2) test from February 27 to June 21, 2020, were included. In addition to the prevalence of asthma, some factors associated with it were investigated. RESULTS: Data from 417,366 subjects were analyzed. Asthma prevalence in children, adults, and global were 3.7%, 3.3%, and 3.3%, respectively. Although the asthma prevalence was lower in SARS-CoV-2 positive over negative patients, significant differences were only found in adults (2.8% vs. 3.7% respectively; odds ratio (OR) = 0.74; 95% confidence interval (CI): 0.71-0.77); but not in children (3.5% vs. 3.8%, respectively; OR = 0.91; 95%CI: 0.76-1.10). Multivariate analysis showed in younger than 18 years that girls and immunosuppression were factors associated with a decrease in the odds to develop asthma. In adults, asthma was positively associated with females, obesity, smoking, immunosuppression, chronic obstructive pulmonary disease, arterial hypertension, and cardiovascular disease. CONCLUSION: The prevalence of asthma in child and adult were lower than those previously reported. Our study seems to support the hypothesis that asthma patients have a lower risk of SARS-CoV-2 infection. Further studies are required to demonstrate the consistency of our findings.

Asthma prevalence, but not allergic rhinitis nor atopic dermatitis, is associated to exposure to dogs in adolescents.

BACKGROUND: Exposure to pets can be a predisposing factor in the development of certain diseases, including allergic diseases. OBJECTIVE: We analyzed the role that exposure to indoor dogs and cats plays in the prevalence of allergic diseases. METHODS: We examined the cross-sectional data of 1056 women and 936 men aged 15 to 18 years; these individuals were selected through stratified and cluster random sampling. We asked all participants about their exposure to indoor dogs and cats during the year that preceded our study. The prevalence of allergic diseases was determined through core questions taken from The International Study of Asthma and Allergies in Childhood questionnaire. RESULTS: The prevalence was 12.7% (95% CI: 11.3%-14.2%) for asthma, 9.0% (95% CI: 7.8%-10.4%) for allergic rhinitis, and 5.2% (95% CI: 4.3%-6.2%) for atopic dermatitis. The multivariate analyses showed that exposure to indoor dogs, but not indoor cats, was associated with asthma prevalence (aOR 1.37; 95% CI: 1.03-1.83), as was male sex (aOR=1.42; 95% CI: 1.08-1.86), a personal history of allergic rhinitis (aOR=3.24; 95% CI: 2.25-4.66), and a maternal history of asthma (aOR=3.06; 95% CI: 1.89-4.98). The population attributable risk for exposure to indoor dogs was 18%. Notably, neither allergic rhinitis nor atopic dermatitis was found to be associated with dog or cat exposure (p> 0.05). CONCLUSION: Exposure to dogs in late adolescence is a factor associated with asthma, although its contribution to the development of asthma should be investigated in new studies.

Elimination of Taenia solium Transmission in Northern Peru.

BACKGROUND: Taeniasis and cysticercosis are major causes of seizures and epilepsy. Infection by the causative parasite Taenia solium requires transmission between humans and pigs. The disease is considered to be eradicable, but data on attempts at regional elimination are lacking. We conducted a three-phase control program in Tumbes, Peru, to determine whether regional elimination would be feasible. METHODS: We systematically tested and compared elimination strategies to show the feasibility of interrupting the transmission of T. solium infection in a region of highly endemic disease in Peru. In phase 1, we assessed the effectiveness and feasibility of six intervention strategies that involved screening of humans and pigs, antiparasitic treatment, prevention education, and pig replacement in 42 villages. In phase 2, we compared mass treatment with mass screening (each either with or without vaccination of pigs) in 17 villages. In phase 3, we implemented the final strategy of mass treatment of humans along with the mass treatment and vaccination of pigs in the entire rural region of Tumbes (107 villages comprising 81,170 people and 55,638 pigs). The effect of the intervention was measured after phases 2 and 3 with the use of detailed necropsy to detect pigs with live, nondegenerated cysts capable of causing new infection. The necropsy sampling was weighted in that we preferentially included more samples from seropositive pigs than from seronegative pigs. RESULTS: Only two of the strategies implemented in phase 1 resulted in limited control over the transmission of T. solium infection, which highlighted the need to intensify the subsequent strategies. After the strategies in phase 2 were implemented, no cyst that was capable of further transmission of T. solium infection was found among 658 sampled pigs. One year later, without further intervention, 7 of 310 sampled pigs had live, nondegenerated cysts, but no infected pig was found in 11 of 17 villages, including all the villages in which mass antiparasitic treatment plus vaccination was implemented. After the final strategy was implemented in phase 3, a total of 3 of 342 pigs had live, nondegenerated cysts, but no infected pig was found in 105 of 107 villages. CONCLUSIONS: We showed that the transmission of T. solium infection was interrupted on a regional scale in a highly endemic region in Peru. (Funded by the Bill and Melinda Gates Foundation and others.).

The characterization of asthma with blood eosinophilia in adults in Latin America.

Objective: To identify and characterize asthma with blood eosinophilia in adults. Methods: This cross-sectional study consisted of 164 asthma patients, aged 18 years or older. Multivariate analyses by logistic regression were performed to identify clinical characteristics and biomarkers associated with asthma with blood eosinophilia (defined as asthma and a peripheral blood eosinophil count ≥400 cells/mm3). To evaluate the diagnostic accuracy of these biomarkers, the sensitivity, specificity and predictive values were calculated. Additionally, the area under the receiver operating characteristic (ROC) curve (AUC) was estimated for each biomarker. Results: Overall, 37.8% (95%CI: 30.7-45.4%) of asthma patients had blood eosinophilia. The following factors were associated with this characteristic: patient age <50 years (OR 3.25; 95% CI: 1.33-7.94), a serum level of IgE ≥300 UI/mL (OR 2.32; 95%CI: 1.14-4.75), and an Asthma Control Test (ACT) score <20 points (OR 3.10; 95%CI: 1.35-4.75); asthma with blood eosinophilia was also associated with a baseline FEV1/FVC <70% (OR 2.68; 95%CI: 1.28-5.59). On the other hand, age <50 years and ACT score <20 showed the highest sensitivity (above 80% each). Serum IgE level ≥300 UI/mL had the highest specificity (almost 68%). Finally, those with an ACT score <20 had the highest AUC (68%). Conclusions: In our study population, one-third of asthmatic adults had asthma with blood eosinophilia. Furthermore, the prevalence was greater in those ≤50 years of age; these patients experienced more severe, more poorly controlled asthma and had higher total serum IgE levels.

Intestinal Microbiota of White Shrimp Penaeus vannamei Under Intensive Cultivation Conditions in Ecuador.

The goal of the study was to characterize the intestinal tract bacterial microbiota composition of Penaeus vannamei in intensive commercial ponds in Ecuador, comparing two shrimp-farming phases: nursery and harvest. Bacterial microbiota was examined by sequencing amplicons V2-V3 of the 16S rRNA using Ion Torrent technology. Archaea sequences were detected in both phases. Sequence analyses revealed quantitative and qualitative differences between the nursery phase and the harvest phase in shrimp intestinal microbiota composition. The main differences were observed at the phylum level during the nursery phase, and the prevailing phyla were CKC4 (37.3%), Proteobacteria (29.8%), Actinobacteria (11.6%), and Firmicutes (10.1%). In the harvest phase, the prevailing phyla were Proteobacteria (28.4%), Chloroflexi (19.9%), and Actinobacteria (15.1%). At the genus level, microbiota from the nursery phase showed greater relative abundances of CKC4 uncultured bacterium (37%) and Escherichia-Shigella (18%). On the contrary, in the microbiota of harvested shrimp, the prevailing genera were uncultured Caldilinea (19%) and Alphaproteobacteria with no other assigned rate (10%). The analysis of similarity ANOSIM test (beta diversity) indicated significant differences between the shrimp microbiota for these two farming phases. Similarly, alfa-diversity analysis (Chao1) indicated that the microbiota at harvest was far more diverse than the microbiota during the nursery phase, which showed a homogeneous composition. These results suggest that shrimp microbiota diversify their composition during intensive farming. The present work offers the most detailed description of the microbiota of P. vannamei under commercial production conditions to date.

Risk factors associated with gastric cancer in Mexico: education, breakfast and chili.

BACKGROUND AND AIM: the aim of the study was to use a validated questionnaire to identify factors associated with the development of gastric cancer (GC) in the Mexican population. METHODS: the study included cases and controls that were paired by sex and ± 10 years of age at diagnosis. In relation to cases, 46 patients with a confirmed histopathological diagnosis of adenocarcinoma-type GC, as reported in the hospital records, were selected, and 46 blood bank donors from the same hospital were included as controls. The previously validated Questionnaire to Find Factors Associated with Gastric Cancer (QUFA-GC©) was used to collect data. Odds ratio (OR) and 95% confidence interval (IC) were estimated via univariate analysis (paired OR). Multivariate analysis was performed by logistic regression. A decision tree was constructed using the J48 algorithm. RESULTS: an association was found by univariate analysis between GC risk and a lack of formal education, having smoked for ≥ 10 years, eating rapidly, consuming very hot food and drinks, a non-suitable breakfast within two hours of waking, pickled food and capsaicin. In contrast, a protective association against GC was found with taking recreational exercise and consuming fresh fruit and vegetables. No association was found between the development of GC and having an income that reflected poverty, using a refrigerator, perception of the omission of breakfast and time period of alcoholism. In the final multivariate analysis model, having no formal education (OR = 17.47, 95% CI = 5.17-76.69), consuming a non-suitable breakfast within two hours of waking (OR = 8.99, 95% CI = 2.85-35.50) and the consumption of capsaicin ˃ 29.9 mg capsaicin per day (OR = 3.77, 95% CI = 1.21-13.11) were factors associated with GC. CONCLUSIONS: an association was found by multivariate analysis between the presence of GC and education, type of breakfast and the consumption of capsaicin. These variables are susceptible to intervention and can be identified via the QUFA-GC

Self-regulation of eating and physical activity is lower in obese female college students as compared to their normal weight counterparts.

OBJECTIVE: Obesity is characterized, among other features, by overeating, reduced physical activity and an abnormal accumulation of body fat. These features are thought to result, at least in part, from the individual's inability to self-regulate their eating and physical activity behaviors (E&PaB). Self-regulation of the E&PaB is a three-step sequential process: self-observation, self-evaluation and self-reaction. However, it is yet unclear whether deficient self-regulation of E&PaB could predispose, facilitate and/or consolidate obesity. Unraveling this issue is fundamental in order to more precisely define the role of self-regulation of E&PaB in the management of obesity. METHODS: This research was focused on the question of whether or not self-regulation of E&PaB is related to obesity in female undergraduate students. This population segment seems especially vulnerable to developing obesity since they undergo a significant shift of their E&PaB upon their university enrollment. To address this question, a cross-sectional study with 108 female undergraduate students with normal weight (n = 80) or obesity (n = 28) was performed, in which self-regulation of eating habits and physical activity was measured by two validated scales and a personal data questionnaire. RESULTS: Female undergraduate students displaying lower E&PaB self-reactions were consistently overweight or obese. In addition, a multivariate analysis identified high levels of self-reaction towards eating habits related to a minor presence of overweight issues or obesity. CONCLUSION: Self-regulation should be an essential component in the strategies for obesity prevention as an integral approach that must include orientation about healthy eating and physical activity behaviors. In addition, further studies on the effect of self-regulation in the treatment of the obesity are needed.

Prevalence of respiratory viruses in wheezing children not older than 24 months of age.

INTRODUCTION: Wheezing in children not older than 24 months of age is a frequent event, and viruses are usually the causative agents. The aim of the study was to estimate the prevalence of respiratory viruses in wheezing children who were not older than 24 months of age and who had no history of asthma. METHODS: Fifty-five Mexican children were included in an analytical cross-sectional study. Nasal secretions were obtained by using sterile rayon-tipped applicators to identify the virus by polymerase chain reaction or reverse transcription-polymerase chain reaction: adenovirus, bocavirus, human rhinovirus, influenza virus type A, human metapneumovirus, parainfluenza, rhinovirus, and respiratory syncytial virus. The prevalence of viral etiology was estimated by dividing the frequency of the identified virus by the number of participants. Ninety-five percent confidence intervals for proportions were calculated. RESULTS: Most of the patients were male (35/55, 63.6%). The average time of evolution of wheezing episode was 3 days. The third part of enrolled population were receiving antibiotics. Respiratory viruses were detected in 33 (60%; 95% CI: 46.8-71.9%) out of 55 cases, and viral coinfection was detected in five cases (9.1%; 95% CI: 3.5-19.9%). Human metapneumovirus was the most frequently identified virus (23.6%), followed by bocavirus (14.5%), respiratory syncytial virus and rhinovirus (12.7% each), and to a lesser extent influenza virus type A and parainfluenza. Rhinovirus was the predominant virus in outpatient children (28.6%). In the inpatient emergency room and inhalotherapy room, human metapneumovirus predominated (41.2 and 16.1%, respectively). CONCLUSION: bocavirus and human metapneumovirus were the most frequently identified viruses in Mexican children who were < 2 years of age, suffered from wheezing, and had no history of asthma.

Characterization and pathogenicity of Vibrio splendidus strains associated with massive mortalities of commercial hatchery-reared larvae of scallop Argopecten purpuratus (Lamarck, 1819).

Three strains (VPAP16, VPAP18 and VPAP23 strains) were isolated as the most predominant organisms from 3 different episodes of massive mortalities of larval cultures of the Chilean scallop Argopecten purpuratus occurred in different commercial hatcheries located in northern Chile. The main aims of this study were to identify the pathogenic strains and investigate their pathogenic activity. Based on selected phenotypic features and sequence identity of the 16S rRNA gene and the housekeeping gene, RNA polymerase α-chain rpoA, all pathogenic strains were identified as Vibrio splendidus. Healthy 10-day-old scallop larvae cultures exhibited mortality percentages of 69.61±3.35%, 79.78±6.11% and 61.73±3.71% after 48 h when were inoculated with 1×10(6) CFU (colony forming units)mL(-1) of VPAP16, VPAP18 and VPAP23 strains, respectively, and evidenced that concentrations ⩾10(4) CFU mL(-1) would probably be detrimental for the larval culture. The main clinical signs observed in challenged larvae for 24h were bacterial swarms on the margins of the larvae, extension and disruption of the velum, detachment of velum cilia cells and digestive tissue necrosis. Otherwise, challenge assays using pathogenic strains stained with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein hydrochloride (5-DTAF)evidenced that after 1h stained bacteria were detected in high density in the digestive gland and the margin of the shell. When larval cultures were inoculated with cell-free extracellular products (ECP) of V. splendidus strains, exhibited larval mortalities higher than 70% (VPAP16), 80% (VPAP18) and 50% (VPAP23) after 24 h, even when ECP were treated with proteinase K or heat, indicating that extracellular pathogenic activity is mainly mediated by non-proteic thermostable compounds. In this study all Koch's postulates were fulfilled and it was demonstrated for the first time the pathogenic activity of V. splendidus strains on reared-larvae of scallop A. purpuratus and prompt the necessity to maintain this species at concentrations lower than 10(4) CFU mL(-1) to avoid episodes of mass mortalities in scallop hatcheries.

Prevalence of Peanut, Tree Nut, Sesame, and Seafood Allergy in Mexican Adults.

OBJECTIVE: To identify the prevalence of perceived and probable allergic reactions to peanuts, tree nuts, sesame seed, or seafood and its association with the personal history of allergic disease. METHODS: A cross-sectional study was performed in four cities of the metropolitan area of Guadalajara, located in western Mexico. Through sampling by gender and age, 1,126 subjects were included. Using a structured questionnaire, we investigated: (i) history of atopic disease, (ii) perception of allergic reaction after food intake, and (iii) probable allergic reaction to peanuts, tree nuts, sesame, or seafood. Prevalence and 95% confidence intervals were calculated. A multivariate analysis of factors associated to perceived and probable allergic reactions to food was performed by logistic regression. RESULTS: Men were 49.8%; mean age was 28.1 years; personal history of atopic disease included: allergic rhinitis (6.9%), asthma (6.8%), and atopic dermatitis (3.8%). Prevalence of perceived and probable food allergy was, respectively: pecan 0.4 and 0.3%; peanut 0.6 and 0.6%; sesame 0.1 and 0.1%; shellfish 4.2 and 4.0% (mainly shrimp); mollusk 0.8 and 0.7%; fish 1.4 and 1.2%. Asthma was significantly associated with perceived and probable allergy to pecans, peanuts, fish, or seafood. Atopic dermatitis was associated with perceived and probable allergic reaction to sea snail, seafood, shellfish, or mollusks. Finally, allergic rhinitis was associated with allergy to shrimp and crustaceans. CONCLUSIONS: This study shows that the prevalence of peanut, tree nut, sesame seed, and seafood allergy in this Mexican population is similar to that reported in developed countries.