Closing the knowledge gap: Helminth parasites of freshwater turtles from the Chaco-Pampa Plain, Southern South America.

Six species of freshwater turtles dominate the Chaco-Pampa Plain in southern South America and their parasites have been relatively understudied, with most records concentrated in Brazil. Particularly in Argentina, there are only scattered records of parasites for most of the turtles that inhabit the region, leaving a large knowledge gap. The purpose of the present contribution is to increase the knowledge of the internal parasites of six species of freshwater turtles from Argentina, after 15 years of fieldwork, by providing new hosts and additional geographic records for many host-parasite relationships. Some molecular sequences of the studied parasites were provided as a tool for better species identification. We processed 433 stomach and fecal samples from live individuals and visceral and soft tissue samples from 54 dissected turtles collected from a wide range and different ecoregions. We found 6230 helminths belonging to 18 taxa (one cestode, 11 digeneans and six nematodes). Fourteen new parasite-host associations are reported here, and for the first time parasites are recorded for Phrynops williamsi. This work contributes significantly to the knowledge of the parasitofauna in freshwater turtles in Argentina, providing a detailed list of parasites present in each turtle species and reporting molecular characters for future studies.

Eugenol as anesthetic for Cnesterodon decemmaculatus (Cyprinodontiformes, Poeciliidae).

Anesthetics are commonly used in fish for surgery and to facilitate capture, handling and transport in aquaculture and experimental procedures. In research, the selection of the anesthetic depends on its properties and on the recovery time. Eugenol has been pointed out as an effective anesthetic for fish, alternative to traditional drugs. Although Cnesterodon decemmaculatus is widely used as a model in ecological bioassays, no anesthetic protocol has been reported for this species. The aim of the present study was to evaluate the induction time (i.e. time to reach anesthetic stage VI) and recovery time in individuals of C. decemmaculatus subjected to eugenol at a fixed concentration, according to sex and pregnancy status. Forty-one fish were divided into three groups: males, pregnant females and non-pregnant females. They were measured for total length, standard length and weight, and the condition factor (K) was calculated. No significant differences in induction and recovery times were found for sex, pregnancy status and K between groups. Results are a contribution toward the development protocol of a standard anesthetic protocol for C. decemmaculatus.

Drosophila nasuta (Diptera, Drosophilidae) in Brazil: a decade of invasion and occupation of more than half of the country.

As a result of human activities and natural dispersal, exotic species can be brought to new areas, where they become established and spread, becoming invaders. These species are responsible for the loss of biodiversity and cause ecosystemic harm throughout the world. In this paper, we report the rapid, broad geographic expansion of the invasive fly Drosophila nasuta in Brazil. An 84% increase was found in its area of occupation in the country compared to previous studies. The present data reveal its arrival to the Pantanal wetlands in a location more than one thousand kilometers from the closest previous record in the Cerrado biome. We present the first record of D. nasuta in the Atlantic Forest in the states of Paraíba and Bahia. We report its introduction in the Amazon Forest in the state of Amazonas approximately 700 kilometers from previous records. The relative abundance of D. nasuta in this biome increased fivefold in comparison to a previous study. In the first decade of invasion in Brazil, D. nasuta has already colonized more than half of the country. The present data reveal its invasive potential and underscore the importance of following up the possible negative effects of this biological invasion.

Systematic assessment of nymphs of Diesingiinae (Pentastomida: Sebekidae) parasitizing Palloceros harpagos (Cyprinodontiformes: Poeciliidae) from Parque Nacional Iguazú, Argentina: filling gaps in an incomplete phylogenetic framework.

During a search for parasites in fishes from Iguazu River, Argentina, a nymph of pentastomid was found encysted on mesenteries of Phalloceros harpagos. The 28S rDNA and COI mt-DNA were used to compare with the sequences deposited in the GenBank. Pentastomid nymphs belong to the subfamily Diesingiinae (Sebekidae) for having chloride cell pores distributed in a single row per annulus; also, the hooks and rows of spines of our material differ to other genera. Present specimens are most likely Diesingia sp., having 63-74 annuli, a U shaped oral cadre with fibers closing anteriorly and a peg like extension of the oral cadre. The 28S rDNA analysis places our samples into a sister group of Alofia sp., but the COI mt-DNA situate them on the base of the clade. In conclusion, our pentastomid positively belongs to Diesingia sp., however, indisputable assignation requires a reliable description of the nymph, or the availability of sequences linking nymphs and adults, which even could provide evidence of a new hitherto undescribed genus. Aditionally, the systematic position of Sebekia oxycephala previously described by P. harpagos is discussed on the basis of our results, allowing us to suggest a re-assignation of such specimens to the genus Diesingia.

Ovarian changes and development of the branchial placenta occurring in Jenynsia lineata (Cyprinodontiformes, Anablepidae).

In viviparous teleosts, intraovarian gestation occurs intrafollicularly, as in poeciliids, or intraluminally, as in goodeids and anablepids. Furthermore, there are two different forms of embryonic nutrition: lecithotrophy and matrotrophy; depending on the species, these can be exclusive or coexist during gestation. In matrotrophic species, nutrients are transmitted from the mother to the embryo and are especially important in species with intraluminal gestation. Jenynsia lineata is a South American viviparous teleost with intraluminal gestation, characterized by eggs with scarce yolk, which is resorbed when embryos are 6 mm long, thus developing a branchial placenta. Using histological, histochemical, and immunohistochemical techniques, the present study describes the characteristics and changes of the ovarian mucosa in J. lineata during gestational and nongestational phases, and analyzes the embryonic pharyngeal epithelium in the branchial placenta. The ovaries of 30 adult female specimens were processed using histological techniques and stained with hematoxylin-eosin, Masson's trichrome, and Alcian Blue pH 2.5/periodic acid Schiff reagent. To detect cell proliferation, we used antiproliferating cell nuclear antigen antibody. In nonpregnant females, eosinophilic granular cells (EGCs) and lymphocytes were identified in the lamina propria of the tunica mucosa, and melanomacrophage centers (MMCs) and fibroblasts were identified adjacent to tissue debris in the ovarian folds'. In the cellular debris, an embryo in resorption was observed. In pregnant females, the ovarian mucosa has thin vascularization branches entering the opercular chamber of the embryos, in close contact with the forming gill processes, thereby establishing a branchial placenta. Active cell replacement was observed in these ovarian branches. The identification of fibroblasts, lymphocytes, EGCs, and MMCs adjacent to tissue debris could indicate that these cell types are involved in the embryonic resorption process. Considering the new data obtained in this study on the branchial placenta of J. lineata, we conclude that cell proliferation could be involved in the development of maternal-embryonic interaction.

Phylogenetic position of the South American freshwater Rhipidocotyle santaensis (Digenea:Bucephalidae) based on partial 28S rDNA.

The family Bucephalidae is comprised of nine subfamilies, the most important being Bucephalinae with eight genera. Among these, the genus Rhipidocotyle has been found in marine and freshwater environments all over the world. Previous studies of Rhipidocotyle santanaensis have dealt with its morphology or host's ecology. Here, we provide a phylogenetic analysis based on two 28S rDNA sequences from R. santanaensis parasitizing the freshwater fish Acestrorhynchus pantaneiro from the Ibera Lagoon (Corrientes Province, Argentina). The 28S rDNA tree showed that it clustered together with Rhipidocotyle species from Middle and North America, suggesting a common history. Bucephalinae appears to have undergone four evolutionary processes: first, the diversification within the same host family; second, more than one successful infection of the same host family in different geographic regions; third, "jumping" between host families; and, finally, successful invasion of the freshwater environment (occurring in at least four different events in the subfamily). We hypothesize that R. santanaensis entered the freshwater environment by a "jumping" event from some unknown marine host family when a seawater ingression took place in South America during the Late Quaternary. This is the first sequenced Bucephalinae species from South America. Further sequencing will help shed light on the evolutionary relationships between South American members of this group from marine and, especially, freshwater environments.

How many species of genus Lernaeopoda Blainville, 1822 (Siphonostomatoida: Lernaeopodidae) are there in the southwestern Atlantic?

The family Lernaeopodidae includes 14 genera parasitizing elasmobranchs. Fourteen species of this family have been cited from Argentina, four of which were found on chondrichthyans. Schroederichthys bivius Mller and Henle and Galeorhinus galeus (Linnaeus) from Argentina harbored parasitic copepods of the genus Lernaeopoda. The objective of this study was to identify the species using an integrative approach. The morphology was examined by Optical Microscopy and Scanning Electron Microscopy and the molecular analysis was based on partial sequences of the COI mtDNA gene. Despite differences in the antenna, antennule, mandible, maxilliped and maxillae among the specimens, the morphological and molecular analyses revealed that they belonged to Lernaeopoda bivia Leigh-Sharpe, 1930. The species so far reported for Argentina are L. bivia and L. galei Kryer, 1837, which are distinguished by the size (less and greater than 7 mm, respectively). Here, we report partial sequences of the COI mtDNA gene of L. bivia for the first time, obtained from eleven specimens attached to the mouth, fins, anal slit and claspers of the two shark hosts. The COI mtDNA gene tree shows that the Lernaeopoda group forms a sister clade with Pseudocharopinus bicaudatus (Kryer, 1837), while the genus Pseudocharopinus does not appear to be a natural group. We propose that the material described from Argentinean waters as L. galei was misidentified and actually belongs to L. bivia. The wide variability within the specimens of L. bivia emphasizes the importance of using an integrative approach to revise the taxonomy of the Lernaeopoda species from all over the world.

Maxiclavella and Praeclavella (Siphonostomatoida: Lernaeopodidae) new genera confirmed by molecular and morphological evidence.

The new genus Maxiclavella is proposed to accommodate Clavella simplex Castro Romero and Baeza Kuroki, 1985, which differs from Clavella species, including long and narrow cephalothorax, small bulla, and simple armature of the antenna and antennule. Praeclavella nasalis, new genus and species, was found parasitizing the olfactory sacs of Isacia conceptionis. Praeclavella nasalis could be differentiated from other Clavella species by a biramous antenna with an exopod shorter than the endopod, the base of the cephalothorax with a large lobular and suborbicular projection on each side, a suborbicular bulla, mandibles without secondary teeth, and a suboval male body type. Males of both genera fit well in the Clavella-clade male type, although they differ from each other in many aspects, mainly in the position of the buccal area, which is oriented ventrally in Maxiclavella and distally in Praeclavella nasalis, and in a genital process, which is present in the latter and absent in the former. Genetic distances of mtDNA COI and 28S rDNA supported the validity of the two new genera parasitizing the same host, I. conceptionis. Also Clavella-branch (Clavellinae Wilson), a key based genera on female specimens is presented.

Molecular phylogenetic relationship between Philometroides tahieli (Nematoda, Philometridae) and other philometrids from South America.

In South America, the family Philometridae is represented by several genera and species. In particular, Philometra and Philometroides are the most speciose genera. In Argentina, only Philometroides tahieli has been reported so far. The main objective of this study was to analyze the phylogenetic relationship between Ps. tahieli and other South American philometrids using molecular data. The molecular analysis was performed using a female specimen of Ps. tahieli found on the opercular muscle of a juvenile Micropogonias furnieri from brackish waters in Argentina. Phylogenetic relationships were studied based on partial sequences of the 18S rDNA and 28S rDNA genes. In the 18S rDNA tree, Ps. tahieli was mainly grouped with other Philometroides from freshwater hosts from China, sharing the site of infection (head tissues or muscles). In the 28S rDNA tree, obtained with fewer sequences, Ps. tahieli is related species from subcutaneous tissues of head. This study contributes with information on philometrids and confirms the presence of different lineages among South American species, with Ps. tahieli representing a new one. Further studies on South American species using more molecular markers and new morphological characters will improve our knowledge of philometrid biodiversity and phylogeny.

First Records of the Invading Species Drosophila Nasuta (Diptera: Drosophilidae) in the Amazon.

Invading species pose a growing threat to biodiversity, ecosystemic systems, regional economies, and public health. In recent decades, South America has received five exotic drosophilids species, some of which have invaded natural ecosystems and caused harm to agriculture. The most recent case is the Asian fly Drosophila nasuta Lamb. In the present study, we record D. nasuta in the Amazon, which is the largest and most biodiverse tropical rainforest in the world. Sampling of drosophilids was carried out between 2012 and 2017 in the Brazilian state of Pará. Drosophila nasuta was first detected on 1st July 2017, with 145 individuals of this species sampled among the 11,496 drosophilids caught. Although at low abundance, D. nasuta was recorded in forest fragments, anthropized fields, and urban environment. The records of the species occurred in the six municipalities of the state of Pará investigated at locations separated by approximately 700 km. In less than 10 years, D. nasuta has occupied approximately 2.5 million km2 in South America. The present findings assist in understanding the susceptibility of tropical forests to biological invasions.

Molecular evidence supports the validity of three Parabrachiella species infecting mugilids.

The parasitic copepod genus Parabrachiella is composed of 70 species, 14 of which are found in South America. The finding of new specimens of Parabrachiella mugilis from Turkey allowed us to compare the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene of this species with those of the South American Parabrachiella exilis and Parabrachiella platensis; all these species are parasites of mugilids. In addition, specimens of Parabrachiella fasciata, Parabrachiella oralis and Parabrachiella dispar from Chile, and Parabrachiella chevreuxi from Argentina were included in the comparison. Our results confirmed that the three Parabrachiella species parasitizing mugilids, which had been identified by morphology, are valid entities. However, P. exilis was recently synonymized with P. mugilis. The latter species showed a great genetic distance from P. exilis (16%) and was closer to Parabrachiella fasciata (13%) and to species with long posterior processes. Parabrachiella exilis and P. platensis (parasite on Mugil cephalus and Mugil liza, respectively) had a low genetic distance (9%) and Parabrachiella kabatai (parasite of Isacia conceptionis) had a low genetic distance (12-13%) from P. fasciata, P. platensis and P. exilis. In addition, the three parasitic copepods from South America have short and round posterior processes compared to other species, which have long posterior processes. Most species with long posterior processes are clustered together in a Pacific Ocean clade (P. hugu from the North Pacific Ocean), with the exception of P. chevreuxi, which has been found in the South Atlantic Ocean. This study adds seven new sequences, making a total of nine sequenced South American species of Parabrachiella.

Flight muscles in falcons (Falconiformes, Falconinae): A quantitative approach.

The family Falconidae has contrasting behaviors on its flight within the subfamilies. Falcons are primarily aerial predators requiring accuracy, high speed, and controlled movements during flight. Caracaras are generalists that seek food while walking and their flight is characterized as slow and erratic. We aimed to explore the muscle mass of the primary wing muscles in several species of Falconinae and to identify possible differences related to the role that these muscles perform during flight. We studied 34 wing muscles in 11 specimens of five species of falcons. The percentage of each muscle with respect to body mass was calculated as well as the total wing muscle mass. The search for differences between muscles of falcons and caracaras was analyzed using Bayesian statistical inference. Published data from Polyborinae were used for comparison. Five muscles were significantly different between both subfamilies mm. latissimus dorsi pars caudalis, biceps brachii, extensor carpi radialis, flexor digitorum superficialis, and extensor digitorum communis. The first two muscles were larger in Polyborinae, which could be useful to achieve more strength and stabilization. In falcons the last three muscles listed were larger, which might be associated with their fast and acrobatic flight. Variations in certain muscles generate, in turn, differences in function, which is reflected in their type of flight and its use. These findings reinforce the modular character of the locomotor system of birds whereby the regions involved in locomotion can have morphological peculiarities according to their lifestyle.

New insights on Pomphorhynchus sphaericus Gil de Pertierra, Spatz et Doma, 1996 (Acanthocephala: Pomphorhynchidae).

The finding of Pomphorhynchus sphaericus in new localities from La Plata River allowed the reevaluation of the species using a taxonomic integrative approach. The newly found specimens in Pimelodus maculatus from Samborombon Bay differ from P. sphaericus by the roots of hooks 1-6 which not form a wide sheet split into 2 apophysis, the slender, separated and equatorial testicles, the position of the cement glands, the shape of the proboscis, the shape and length of lemnisci, and the eggs size. Despite the notorious observed morphological differences, the COI mtDNA analysis confirmed that Pomphorhynchus individuals are the same conspecific, and showed that there is a high phenotypical plasticity in this species. Pomphorhynchus sphaericus is the first South American species analyzed to a DNA level (COI mtDNA, ITS, and 18S rDNA genes). The molecular analysis relates P. sphaericus to P. bulbocolli and P. purhepechus.

Albinism in Artibeus planirostris (Chiroptera, Phyllostomidae) in the Caatinga biome and updated list of albino bats in Brazil.

Albinism is a genetic disorder that results in a deficiency in melanin production. This type of chromatic alteration may affect several vertebrate species, but is rarely observed in nature. In Brazil, for the bat group, only 15 albino individuals have been registered. Here we present a new case for Artibeus planirostris. A pregnant female of this species with alopecia was captured in the Caatinga biome. A compilation of the distribution of albino bats in Brazil is presented.

Gut Microbiota and Neuroplasticity.

The accumulating evidence linking bacteria in the gut and neurons in the brain (the microbiota-gut-brain axis) has led to a paradigm shift in the neurosciences. Understanding the neurobiological mechanisms supporting the relevance of actions mediated by the gut microbiota for brain physiology and neuronal functioning is a key research area. In this review, we discuss the literature showing how the microbiota is emerging as a key regulator of the brain's function and behavior, as increasing amounts of evidence on the importance of the bidirectional communication between the intestinal bacteria and the brain have accumulated. Based on recent discoveries, we suggest that the interaction between diet and the gut microbiota, which might ultimately affect the brain, represents an unprecedented stimulus for conducting new research that links food and mood. We also review the limited work in the clinical arena to date, and we propose novel approaches for deciphering the gut microbiota-brain axis and, eventually, for manipulating this relationship to boost mental wellness.

Plasma cytokines during acute human fascioliasis.

Fascioliasis is a foodborne trematode endemic worldwide. Children under 15 years have the highest prevalence of infection. We hypothesized that acute fascioliasis would be associated with more pronounced cytokine changes than in chronic disease or no helminth infections. To test this hypothesis, 33 children who lived in the Peruvian highlands were classified into 3 groups: acute fascioliasis, chronic fascioliasis, and no helminth infection. Type Th1, Th2, and Th17 cytokines were measured in plasma by cytometric bead array. Children with acute infection had higher levels of IL-5 and IL-17 compared with controls (p < 0.001 and p < 0.007, respectively). The increased IL-5 plasma concentration in children with acute infection was associated with the eosinophilia found in that group.

Molecular data reveal hidden diversity of the genus Clinostomum (Digenea, Clinostomidae) in Argentina, with the description of a new species from Ardea cocoi (Ardeidae).

The genus Clinostomum has been recently a subject of a large number of molecular phylogenetic studies that have uncovered a larger species diversity than we thought. In Argentina, only two nominal species have been reported, namely C. detruncatum and C. marginatum. Three putative species represented by metacercariae were recently molecularly diagnosed, and there are at least two additional metacercarial morphotypes diagnosed on morphological grounds. Here, we molecularly characterized specimens of Clinostomum sampled from freshwater fishes and fish-eating birds from Argentina through mtDNA cytochrome c oxidase subunit I (COI). Unexpectedly, the phylogenetic analysis uncovered three new additional genetic lineages, two of them corresponding to metacercarial stages and another matching COI sequences of C. heluans Braun, 1899, being considered conspecific, whereas the others still require formal description. Additionally, we add a new host species for a lineage molecularly diagnosed in a previous study. The adult specimens recovered from A. cocoi in Buenos Aires Province represented a new species clearly distinguished from the two species previously reported in Argentina. Clinostomum detruncatum is distinguished from the new species by possessing a characteristic tenoidean uterus, and testes located more posteriorly. Clinostomum marginatum is morphologically similar but differs from the new species in having rounded ovary, posterior testis lobated, and lateral cirrus-sac and displacing the anterior testis, and vitelline follicles not extending beyond the caeca end. Our study raises the number of Clinostomum species in Argentina up to 10. We describe the new species herein.

Randomized clinical trial to evaluate safety and efficacy of convalescent plasma use among hospitalized patients with COVID-19 (PERUCONPLASMA): a structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: The general objective of this study is to test the hypothesis that administration of convalescent plasma from donors with previous diagnosis of severe COVID-19 pneumonia is safe and associated with a decrease in all-cause in-hospital mortality among hospitalized patients with COVID-19 at 30 days in comparison with standard treatment alone. The secondary objectives are as follows: (1) to assess the efficacy of convalescent plasma to reduce the length of hospitalization, (2) to assess the efficacy of convalescent plasma to reduce the length of ICU stay, and (3) to assess the efficacy of convalescent plasma on reducing the requirement of invasive mechanical ventilation or ICU stay. TRIAL DESIGN: PERUCONPLASMA is a IIb phase open label, randomized, superiority clinical trial with 1:1 allocation taking place in real life routine clinical practice at public hospitals in Lima, Peru. Participants will be randomized to receive convalescent plasma along with local standard treatment or local standard treatment alone. After allocation, all participants will be followed for a total of 30 days or until hospital discharge, whichever occurs first. PARTICIPANTS: The population for the study are patients with severe disease with a confirmed laboratory test for SARS-CoV-2 infection hospitalized in 3 tertiary-care hospitals in Lima, Peru. Subjects are eligible for the trial if they meet all of the following inclusion criteria: 1. Age 18 or older 2. Hospitalization due to COVID-19 with laboratory confirmation (either with serologic, molecular, or antigen test along with a compatible clinical presentation) 3. Severe or critical COVID-19 disease Severe illness was defined by 2 or more of the following: Respiratory rate of 22 or more Hypoxemia with oxygen saturation equal or less than 93% Abnormal blood gas analysis (PaO2 < 60 mmHg, PaCO2 > 50 mmHg, or Pa/FiO2 < 300) Critical disease was defined by either: Mechanical ventilation requirement less than 72 h. Shock. 4. Capacity to provide informed consent (patient or patient's direct relative) 5. Availability of convalescent plasma units compatible with ABO blood type of the subject. EXCLUSION CRITERIA: Subjects are not eligible for the trial if they meet any of the following criteria: 1. Contraindication for transfusion (e.g., prior anaphylaxis, congestive heart failure) 2. Hemodynamic instability (PA < 60 mmHg refractory to vasopressors) 3. Uncontrolled concomitant infections\ 4. Stupor or coma 5. Platelets < 50,000/µL or disseminated intravascular coagulation 6. Serum creatinine > 3.5 mg/dL or dialysis requirement 7. Total bilirubin > 6 mg/dL or jaundice of unknown etiology 8. Myocardial infarction or acute coronary syndrome 9. Active or recent (< 7 days) intracranial hemorrhage 10. Pregnancy Donors: The donors have to meet the following criteria: male between 30 and 60 years with a previous diagnosis of severe COVID-19-associated pneumonia within the last 3 months, with resolution of symptoms of at least 28 days. The rationale for including donors with severe disease is to maximize the probability of collecting convalescent plasma units with high titer of neutralizing antibodies, as the technology to measure this specific type of antibodies is not routinely available in Peru. Aliquots of plasma will be stored for future quantification of neutralizing antibodies. INTERVENTION AND COMPARATOR: Convalescent plasma from donors with previous severe COVID-19 is the investigational medical product. The experimental group will receive 1 to 2 units of 200 to 250 ml of convalescent plasma along with local standard treatment. The control group will receive local standard treatment alone. The participants randomized to plasma will have evaluations at 6 h and 24 h to specifically evaluate possible post transfusion events. All the participants will be evaluated at day 3, day 7, and day 30 after enrolment. MAIN OUTCOMES: Safety outcome: Incidence of serious adverse reactions related to convalescent plasma transfusion within 24 h after convalescent plasma administration. Efficacy outcomes: Mortality from any cause during hospitalization at 30 days post randomization. Length of hospitalization at 30 days post randomization or until hospital discharge. Duration of mechanical ventilation at 30 days post randomization or until hospital discharge. Length of hospitalization in an intensive care unit at 30 days post randomization or until hospital discharge. Exploratory: Oxygen requirement evolution at days 3 and 7. Score Sequential Organ Failure Assessment (SOFA) evolution at days 3 and 7. Dynamics of inflammatory marker (lymphocyte, C-reactive protein (CRP), D-dimer, lactate dehydrogenase (LDH)) evolution at days 3 and 7. Proportion of patients progressing to multi-organ failure at 30 days post randomization or until hospital discharge. Proportion of transfusion related adverse reactions at 30 days post randomization or until hospital discharge. RANDOMIZATION: Randomization will be carried out within the electronic case report form (eCRF) in 1:1 ratio (receive plasma/control) in a randomization process established by blocks of size 2, 4, and 6. Allocation to the treatment arm of an individual patient will not be available to the investigators before completion of the whole randomization process. Randomization blocks will be performed with "ralloc", Stata's randomization process v.16.0. Randomization through the eCRF will be available 24 h every day. BLINDING (MASKING): Both the participants and study staff will be aware of the allocated intervention. Blinded statistical analysis will be performed. NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): The sample size was calculated using the Fleiss formula with continuity correction to detect a mortality reduction from 50 to 20% between the two treatment arms with a confidence level of 95% and a power of 80%. Based on this information, a total of 45 patients per arm would be needed. After adjustment for a drop-out rate of 10% after enrolment, a total of 50 patients per arm (100 patients in total) will be enrolled. TRIAL STATUS: Current protocol version: 5.0 dated January 04, 2021. Recruitment started on September 21, 2020, and is expected to finish by the end of March 2021. TRIAL REGISTRATION: Peruvian Register of Clinical Trials (REPEC) ID: PER-016-20, registered on June 27, 2020. Clinicaltrials.gov ID: NCT04497324 , registered on August 4, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this letter serves as a summary of the key elements of the full protocol.

Invasion and Spreading of Drosophila nasuta (Diptera, Drosophilidae) in the Caatinga Biome, Brazil.

Biological invasions are one of the main causes of biodiversity loss, and it is essential to understand the pattern and rate of expansion of invasive species outside their native distribution. In this study, we documented the invasion of the Asian fruit fly, Drosophila nasuta Lamb, in the Caatinga, and measured its geographical distribution in this environment, which covers 11% of the Brazilian territory. We collected drosophilids in eight sites distributed in the north of the Caatinga (in the state of Ceará), in the south (in Bahia), in the east (in Pernambuco), and in the west (in Piauí), as well as in sites in the central area of the biome. Drosophila nasuta occurred in all areas and was one of the most frequently occurring species in half of the sampled sites. We observed greater abundance in areas with arboreal vegetation and a possible preference of this species for areas with higher annual rainfall in the Caatinga. Of all the biomes where D. nasuta is found in Brazil, the area occupied in the Caatinga is the largest documented to date. Our results show D. nasuta's success in invading the Caatinga and the vast area this species has colonized in this biome. The success of this invasion can be explained by the high fertility and short life cycle as well as by the ability of D. nasuta to use different trophic resources.