Influencia de la densidad de cultivo sobre el estrés en juveniles de Oreochromis niloticus cultivados en sistemas con tecnología Biofloc

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en AcuiculturaEl empleo de organismos acuáticos para el cultivo en altas densidades como un medio para aumentar la productividad se ha convertido en una tendencia importante de los acuicultores a nivel mundial. El objetivo de ésta investigación fue determinar los efectos de diferentes densidades de cultivo sobre los parámetros bioquímicos y hematológicos en individuos juveniles de O. niloticus cultivados en un sistema de producción con tecnología biofloc. Se trabajó con tres tratamientos, en las siguientes cargas iniciales: 3.12, 8.42 y 15.57 Kg/m3 (T1, T2 y T3, respectivamente), en un volumen de agua de 250 L y peso total promedio de 88.9 ± 2.54 g. Los tratamientos fueron mantenidos en una relación de C:N de 15:1. El experimento duró 57 días, y en ese transcurso se colectó tres muestras de sangre (al inicio, intermedio, y final del experimento), mediante punción de la vena caudal. Se extrajo 0.5 mL del 20% de la población por cada repetición para cuantificar parámetros bioquímicos, y 0.5 mL de otro 20% de la población para cuantificar parámetros hematológicos a través de métodos estandarizados. Se realizaron biometrías quincenales para evaluar el desempeño productivo de la tilapia. Los resultados mostraron un incremento en los parámetros bioquímicos y hematológicos al inicio del experimento en los tres tratamientos, con un descenso hacia el final del experimento en los niveles de cortisol, hemoglobina, hematocrito y en el conteo de eritrocitos. Se presentó diferencias significativas en temperatura, conductividad y sólidos sedimentables de T1 y T2 frente a T3; mientras que se determinó diferencias entre todos los tratamientos en oxígeno disuelto, porcentaje de saturación, pH, nitrógeno amoniacal total y amonio no ionizado y nitrato (p<0.05), sin embargo, los datos obtenidos se encuentran dentro del rango óptimo para el cultivo, a excepción de la conductividad eléctrica. Los resultados referentes a parámetros productivos indicaron inhibición del crecimiento en los tres tratamientos durante las primeras 4 semanas, luego del cual hubo un incremento del peso, alcanzando T2 y T3 mayor ganancia de peso, respecto de T1. A su vez, se obtuvo sobrevivencias superiores al 95% en todos los tratamientos.The use of aquatic organisms for cultivation at high density as a means to increase productivity has become an important trend for fish farmers worldwide. The objective of this research was to determine the effects of different culture densities on the biochemical and hematological parameters in juvenile O. niloticus individuals cultured in a production system with biofloc technology. We worked with three treatments, in the following initial loads: 3.12, 8.42 and 15.57 Kg/m3 (T1, T2 and T3, respectively), in a volume of water of 250 L and average total weight of 88.9 ± 2.54 g. The treatments were maintained in a C: N ratio of 15: 1. The experiment lasted 57 days, and in this course three samples were taken (at the beginning, intermediate, and end of the experiment), by puncture of the caudal vein. We extracted 0.5 mL of 20% of the population for each tanque to quantify biochemical parameters, and 0.5 mL of another 20% of the population to quantify hematological parameters through standardized methods. Biweekly biometries were performed to evaluate the productive performance of the tilapia. The results showed an increase in the biochemical and hematological parameters at the beginning of the experiment in the three treatments, with a decrease towards the end of the experiment in the levels of cortisol, hemoglobin, hematocrit and in the erythrocyte count. There were significant differences in temperature, conductivity and sedimentable solids of T1 and T2 versus T3; while differences were determined between all the treatments in dissolved oxygen, percentage of saturation, pH, total ammonia nitrogen and non-ionized ammonium and nitrate (p <0.05). However, the data obtained are within the optimum range for the cultivation, except for electrical conductivity. The results referring to productive parameters indicated growth inhibition in the three treatments during the first 4 weeks, after which there was an increase in weight, reaching T2 and T3 greater weight gain, with respect to T1. In turn, survival of more than 95% was obtained in all treatments.Tesi

Comparison of cytokines levels among COVID-19 patients living at sea level and high altitude

Background: At the end of 2019, a novel coronavirus denominated SARS-CoV-2 rapidly spread through the world causing the pandemic coronavirus disease known as COVID-19. The difference in the inflammatory response against SARS-CoV-2 infection among people living at different altitudes is a variable not yet studied. Methods: A descriptive cross-sectional study was performed in two Peruvian cities at different altitudes for comparison: Lima and Huaraz. Five important proinflammatory cytokines were measured including: IL-6, IL-2, IL-10, IFN-γ and TNF-α using ELISA assays. Results: A total of 35 COVID-19 patients and 10 healthy subjects were recruited from each study site. The mean levels of IL-6 (p < 0.03) and TNF-α (p < 0.01) were significantly different among the study groups. In the case of IL-6, patients from Lima had a mean level of 16.2 pg/ml (healthy) and 48.3 pg/ml (COVID-19), meanwhile, patients from Huaraz had levels of 67.3 pg/ml (healthy) and 97.9 pg/ml (COVID-19). Regarding TNF-α, patients from Lima had a mean level of 25.9 pg/ml (healthy) and 61.6 pg/ml (COVID-19), meanwhile, patients from Huaraz had levels of 89.0 pg/ml (healthy) and 120.6 pg/ml (COVID-19). The levels of IL-2, IL-10 and IFN-γ were not significantly different in the study groups. Conclusion: Patients with COVID-19 residing at high-altitude tend to have higher levels of inflammatory cytokines compared to patients living at sea level, particularly IL-6 and TNF-α. A better understanding of the inflammatory response in different populations can contribute to the implementation of therapeutic and preventive approaches. Further studies evaluating more patients, a greater variety of cytokines and their clinical impact are required.National Research Foundation of KoreaRevisión por pare

Unidentified dengue serotypes in DENV positive samples and detection of other pathogens responsible for an acute febrile illness outbreak 2016 in Cajamarca, Peru

Objective: To describe the prevalence of dengue virus serotypes, as well as other viral and bacterial pathogens that cause acute febrile illness during an outbreak in Cajamarca in 2016. Results: Dengue virus (DENV) was the most frequent etiologic agent detected in 25.8% of samples (32/124), followed by Rickettsia spp. in 8.1% (10/124), Zika virus in 4.8% (6/124), Chikungunya virus 2.4% (3/124) and Bartonella bacilliformis 1.6% (2/124) cases. No positive cases were detected of Oropouche virus and Leptospira spp. DENV serotypes identification was only achieved in 23% of the total positive for DENV, two samples for DENV-2 and four samples for DENV-4. During the 2016 outbreak in Cajamarca-Peru, it was observed that in a large percentage of positive samples for DENV, the infecting serotype could not be determined by conventional detection assays. This represents a problem for the national surveillance system and for public health due to its epidemiological and clinical implications. Other viral and bacterial pathogens responsible for acute febrile syndrome were less frequently identified.Revisión por pare

A silent public health threat: emergence of Mayaro virus and co-infection with Dengue in Peru

Objective: To describe frequency and clinical characteristics of MAYV infection in Piura, as well as the association of this pathogen with DENV. Results: A total of 86/496 (17.3%) cases of MAYV were detected, of which 54 were MAYV mono-infection and 32 were co-infection with DENV, accounting for 10.9% and 6.4%, respectively. When evaluating monoinfection by MAYV the main groups were 18–39 and 40–59 years old, with 25.9% and 20.4% respectively. Co-infections were more common in the age group 18–39 and those > 60 years old, with 34.4% and 21.9%, respectively. The most frequent clinical presentation were headaches (94.4%, 51/54) followed by arthralgias (77.8%, 42/54). During the 8-month study period the most cases were identified in the months of May (29.1%) and June (50.0%).National Research Foundation of KoreaRevisión por pare

Dengue diagnosis in an endemic area of Peru: Clinical characteristics and positive frequencies by RT-PCR and serology for NS1, IgM, and IgG

This work was supported by Cienciativa of CONCYTEC Peru, under contract number 164-2016-FONDECYT, and the Programa Nacional de Innovación para la Competitividad y Productividad (Innóvate Perú), under contract number 116-PNICP-PIAP-2015.Background: Huánuco is a central eastern region of Peru whose geography includes high forest and low jungle, as well as a mountain range that constitutes the inter-Andean valleys. It is considered a region endemic for dengue due to the many favorable conditions that facilitate transmission of the virus. Methods: A total of 268 serum samples from patients in Huánuco, Peru with an acute febrile illness were assessed for the presence of dengue virus (DENV) via RT-PCR and NS1, IgM, and IgG ELISA during December 2015 and March 2016. Results: DENV was detected in 25% of samples via RT-PCR, 19% of samples by NS1 antigen ELISA, and 10.5% of samples by IgM ELISA. DENV IgG was detected in 15.7% of samples by ELISA. The most frequent symptoms associated with fever across all groups were headache, myalgia, and arthralgia, with no significant difference between the four test methods Conclusions: In this study, DENV was identified in up to 25% of the samples using the standard laboratory method. In addition, a correlation was established between the frequency of positive results and the serological tests that determine NS1, IgM, and IgG. There is an increasing need for point-of-care tests to strengthen epidemiological surveillance in Peru.Revisión por paresRevisión por pare

Variations in cervico-vaginal microbiota among HPV-positive and HPV-negative asymptomatic women in Peru

Objective: To characterize the cervicovaginal microbiota of HPV-positive and HPV-negative asymptomatic Peruvian women, by identifying the presence of 13 representative bacteria genus. Results: A total of 100 HPV-positive and 100 HPV-negative women were matched by age for comparison of microbiota. The following bacteria were more frequently identified in HPV-positive patients compared to HPV-negative: Eubacterium (68 vs 32%), Actinobacteria (46 vs 33%), Fusobacterium (11 vs 6%) and Bacteroides (20 vs 13%). A comparison between high-risk and low-risk genotypes was performed and differences were found in the detection of Actinobacteria (50 vs 33.33%), Bifidobacterium (50 vs 20.83%) and Enterococcus (50 vs 29.17%).Revisión por pare

Clinical characteristics and molecular detection of bordetella pertussis in hospitalized children with a clinical diagnosis of whooping cough in Peru

Background and Objectives: Pertussis is an infectious disease caused by the Gram-negative bacterium Bordetella pertussis. In Peru, actual public health programs indicate that vaccination against B. pertussis must be mandatory and generalized, be-sides all detected cases must be reported. The objective of this study was to determine the prevalence of B. pertussis among children under five years of age with a presumptive diagnosis of whopping cough in Cajamarca, a region located in northern Peru. Materials and Methods: The population of this cross-sectional study were children under 5 years old hospitalized as presumptive cases of pertussis during December 2017 to December 2018. The nasopharyngeal samples were analyzed by real-time PCR for the detection of B. pertussis. Results: B. pertussis was identified as PCR + in 42.3% of our sample (33/78). The clinical presentation that was observed most frequently includes paroxysmal coughing (97%), difficulty breathing (69.7%), cyanosis (72.7%) and post-tussive em-esis (60.6%). Additionally, pneumonia was the most observed complication (33.3%). Four of the patients with PCR+ for B. pertussis presented only lymphocytosis, five only leukocytosis, two patients with decreased leukocytosis and lymphocytes and only one patient with leukopenia and relative lymphocytosis. There was a percentage of 84.8% of unvaccinated children in the PCR+ group. Finally, the mother was the most frequent symptom carrier (18.2%). Conclusion: In conclusion, in the studied population there is a high rate of PCR+ cases for B. pertussis. Laboratory values may show leukopenia or lymphopenia in patients with pertussis. It is necessary to use appropriate laboratory diagnostic tests in all infants with respiratory symptoms for B. pertussis. Since, the clinical diagnosis overestimates the diagnosis of pertussis.Revisión por pare

Genotype-specific prevalence of human papillomavirus infection in asymptomatic Peruvian women: a community-based study

Objective: To determine the general and genotype-specific prevalence of HPV and to identify potential risk factors for the infection in a population-based screening of Peruvian women. Results: A total of 524 samples were analyzed by PCR and a total of 100 HPV positive samples were found, of which 89 were high-risk, 19 were probably oncogenic, 9 were low-risk and 27 other HPV types. The 26–35 and 36–45 age groups showed the highest proportion of HPV positive samples with a total of 37% (37/100) and 30% (30/100), respectively. Moreover, high-risk HPV was found in 33.7% of both groups and probably oncogenic HPV in 52.6% and 31.6%, respectively. High-risk HPV were the most frequent types identified in the population studied, being HPV-52, HPV-31 and HPV-16 the most commonly detected with 17.6%, 15.7% y 12.9%, respectively. Demographic characteristics and habits were assessed in the studied population. A total of 62% high-risk HPV were detected in married/cohabiting women. Women with two children showed the highest proportion (33.8%) of high-risk HPV, followed by women with only one child (26.9%). Those women without history of abortion had a higher frequency of high-risk HPV (71.9%), followed by those with one abortion (25.8%).Revisión por pare

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality