Effect of the Insecticide Chlorpyrifos on Behavioral and Metabolic Aspects of the Spider Polybetes pythagoricus.

The toxicity of pesticides to organisms depends on the total amount of chemical exposure. Toxicity can be minimized if the organism recognizes the pesticide and alters its behavior. Furthermore, the physical barrier of cuticular hydrocarbons can prevent the entrance of the pesticide into the organism. Finally, if the pesticide enters the body, the organism experiences physiological changes favoring detoxification and the maintenance of homeostasis. We analyzed the behavioral and metabolic response of the spider Polybetes pythagoricus at different times of exposure to the organophosphate pesticide chlorpyrifos. First we observed that the individuals are capable of recognizing and avoiding surfaces treated with pesticides based on a behavioral analysis. Subsequently, we characterized cuticular hydrocarbons as a possible barrier against pesticides. Then we observed that the pesticide provoked histological damage, mainly at the level of the midgut diverticula. Finally, we analyzed the activity of several of the spider's enzymes linked to oxidative stress after exposure to chlorpyrifos for different lengths of time (6, 24, and 48 h). We observed that catalase activity was high at the start, whereas the activity of superoxide dismutase and glutathione S-transferase changed significantly at 48 h. Lipid peroxidation became high at 6 h, but decreased at 48 h. In conclusion, although P. pythagoricus can avoid contact with chlorpyrifos, this pesticide causes activation of the antioxidant system when it enters the body. Our results make a significant contribution to the ecotoxicology of spiders. Environ Toxicol Chem 2023;42:1293-1308. © 2023 SETAC.

Embryonic and post-embryonic development of the spider Polybetes pythagoricus (Sparassidae): A biochemical point of view.

Analysis of energy expense during development has achieved special interest through time on account of the crucial role of the consumption of resources required for offspring survival. Spider eggs have a fixed composition as well as some initial energy that is supplied by mothers. These resources are necessary to support the metabolic expense not only through the embryonic period but also during the post-embryonic period, as well as for post emerging activities before spiderlings become self-sustaining. Depletion of these resources would be critical for spiders since it could give rise to prey competition as well as filial cannibalism. Even though spiders represent a megadiverse order, information regarding the metabolic requirements during spiders development is very scarce. In this study, we analyse the changes in protein, lipid and carbohydrate content as well as the variation in lipovitellin reserves and hemocyanin content during Polybetes pythagoricus development. Our results show that lipovitellins and phospholipids represent the major energy source throughout embryonic and post-embryonic development. Lipovitellin apolipoproteins are gradually consumed but are later depleted after dispersion. Phosphatidylethanolamine is mainly consumed during the post-embryonic period, while triacylglycerides are consumed after juveniles' dispersion. Finally, hemocyanin concentration starts to increase in postembryonic stages.

Serie de Casos de Leishmaniasis Detectados en Centros Hospitalarios del Departamento de Caaguazú, Paraguay en 2019

Resumen La leishmaniasis es la tercera de las enfermedades de transmisión vectorial a humanos en importancia por el número de casos y la población en riesgo. En Paraguay la leishmaniasis cutánea es una enfermedad endémica atribuida en casi todos los casos a Leishmania (Viannia) braziliensis. El objetivo del artículo es describir las características demográficas y clínicas de una serie de casos de pacientes con leishmaniasis en el V departamento de Caaguazú y departamentos cercanos, epidemiológicamente endémicos. Se reportan casos diagnosticados en los meses enero a diciembre del año 2019. Los casos se presentaron en el departamento de Caaguazú, abarcando los diferentes distritos que componen y departamentos cercanos como Canindeyú, Alto Paraná y Guaira. De los casos registrados (9 casos) fueron hombres y (6 casos) tuvieron entre 50 a 70 años de edad. La lesión estuvo situada mayormente en el tabique nasal en 8 casos, con una evolución de menos de 10 años (6 casos) y en 4 casos dejo cicatriz. Solo 3 casos completaron su tratamiento. Se sugiere realizar el reporte de casos para tener un panorama de los casos de leishmaniasis en Paraguay como vigilancia sanitaria de la enfermedad y localizar focos de contagio.

Abstract Leishmaniasis is the third most important vector-borne diseases in humans due to the number of cases and the population at risk. In Paraguay, cutaneous leishmaniasis is an endemic disease attributed in almost all cases to Leishmania (Viannia) braziliensis. The objective of the article was to describe the demographic and clinical characteristics of a series of cases of patients with leishmaniasis in the V department of Caaguazú and nearby departments, epidemiologically endemic. Cases diagnosed in the months of January to December of the year 2019 are reported. The cases occurred in the department of Caaguazú, covering the different districts that make up and nearby departments such as Canindeyú, Alto Paraná and Guaira. Of the registered cases (9 cases) were men and (6 cases) were between 50 and 70 years of age. The lesion was located mainly in the nasal septum in 8 cases, with an evolution of less than 10 years (6 cases) and in 4 cases it left a scar. Only 3 cases completed their treatment. It is suggested to carry out the case report to have an overview of Leishmania cases in Paraguay as a health surveillance of the disease and to locate sources of contagion.

Arachnid Hemocyanins.

Hemocyanin (Hc), a copper-containing extracellular multimeric protein, is the major protein component of hemolymph in different arachnid groups. Hc possesses 7 or 8 very well-characterized types of monomers with molecular weights ranging from 70 to 85 kDa, organized in hexamers or multiple of hexamers. The present chapter compiles the existing data with relation to the function of this protein in the arachnids. Hc has as main function the reversible transport of O2, but it shows many secondary though not less important functions. With reference to this, it has been described that Hc can transport hydrophobic molecules (lipid-derived hormones and lipids) to the different organs, having a key role in the lipid transport system. In arachnids, like in other arthropods and invertebrates, Hc has phenoloxidase function which is related to different metabolic processes such as melanin formation and defense against pathogens. In addition, Hc has additional defensive functions since it can serve as precursor for the production of antimicrobial peptides. In short, the evolution of this protein has led to the development of multiple functions essential for organisms possessing this protein.

Non-dopaminergic vs. dopaminergic treatment options in restless legs syndrome.

Two types of drugs have been extensively investigated for the treatment of restless legs syndrome (RLS)/Willis-Ekbom disease (WED): dopamine agonists and α2δ ligands to the α2δ subunit of calcium channels. Comparative studies show that both classes of drugs are similarly effective in treating RLS symptoms over the short- and long-term. While dopamine agonists are more effective in treating periodic limb movements (PLMs), α2δ ligands are more effective in consolidating sleep. However, given the fact that dopamine agonists cause high rates of augmentation of symptoms, recent international guidelines recommend that whenever possible the initial treatment of choice should be an α2δ ligand. In fact, the most effective preventive strategy involves not using dopaminergic agents unless absolutely necessary. Indeed, should dopaminergic treatment be needed to handle the symptoms effectively, then it is recommended that the dopaminergic load be reduced by using the lowest effective dose for the shortest possible period of time. However, it must be taken into account that the only α2δ ligand approved for RLS/WED is gabapentin enacarbil, which is not yet available in Europe. Furthermore, recent studies have also reported on the efficacy of opioids as a second-line treatment of RLS/WED, following treatment failure with dopamine agonists. Recent guidelines have taken these new data into account and highlight that a low dose of an opioid (prolonged-release oxycodone or methadone) may be considered in patients with very severe augmentation of symptoms. Alternative non-dopaminergic treatment concepts based on glutamatergic and adenosinergic mechanisms are currently in development, and are likely to provide encouraging therapeutic alternatives.

An evaluation study of enzyme-linked immunosorbent assay (ELISA) using recombinant protein Pap31 for detection of antibody against Bartonella bacilliformis infection among the Peruvian population.

Reliable laboratory testing is of great importance to detect Bartonella bacilliformis infection. We evaluated the sensitivity and specificity of the enzyme-linked immunosorbent assay (ELISA) using recombinant protein Pap31 (rPap31) for the detection of antibodies against B. bacilliformis as compared with immunofluorescent assay (IFA). Of the 302 sera collected between 1997 and 2000 among an at-risk Peruvian population, 103 and 34 samples tested positive for IFA-immunoglobulin G (IgG) and IFA-IgM, respectively. By using Youden's index, the cutoff values of ELISA-IgG at 0.915 gave a sensitivity of 84.5% and specificity of 94%. The cutoff values of ELISA-IgM at 0.634 gave a sensitivity of 88.2% and specificity of 85.1%. Using latent class analysis, estimates of sensitivity and specificity of almost all the assays were slightly higher than those of a conventional method of calculation. The test is proved beneficial for discriminating between infected and non-infected individuals with the advantage of low-cost and high-throughput capability.

Shewanella algae en un paciente con diarrea crónica: primer caso en Costa Rica / Shewanella algae in a patient with chronic diarrhea: first case in Costa Rica

Se presenta el caso de un paciente masculino, vecino de Pavas-San José, con historia de diarrea crónica. En el coprocultivo se identificó shewanella algae. Casos de infección en humanos por esta bacteria son raros y se han encontrado, predominantemente localizadas, en piel, oídos y tejidos blandos con o sin bacteremia, en la mayoría de los cuales existe el antecedente de contacto con ambientes marinos. Shewanella algae es sensible a aminoglicósidos, carbapanemes, eritromicina y quinolonas, pero resistente a penicilinas. La sensibilidad a ampicilina y cefalosporinas es variable. Nuestro paciente fue tratado con cefalexina y tuvo una respuesta satisfactoria al mismo, con cese de los síntomas. De acuerdo con nuestro conocimiento este el primer caso documentado, en Costa Rica, de infección gastrointestinal por esta bacteria.

We report herein the case of a male patient, from Pavas, San Jose, with chronic diarrhea whose stool culture grew Shewanella algae. Infections caused by this micro-organism are infrequent and most commonly involve ears, skin and soft tissue, with or without bacteremia and are usually linked to ocean contact in warm climate countries. Shewanella algae is sensitive to aminoglycosides, carbapenems, erythromycin and quinolones, but resistant to penicillin. Sensitivity to amplicilin and cephalosporins is variable. Our patient was treated withcefalexin, with satisfactory results. To our knowledge, this is the first documented case in Costa Rica of gastrointestinal infection caused by this microorganism.

Population genetic analysis of Bartonella bacilliformis isolates from areas of peru where Carrion's disease is endemic and epidemic.

Carrion's disease is caused by infection with the alpha-proteobacterium Bartonella bacilliformis. Distribution of the disease is considered coincident with the distribution of its known vector, the sand fly Lutzomyia verrucarum. Recent epidemics of B. bacilliformis infections associated with atypical symptomatology in nonendemic regions have raised questions regarding the historic and present distribution of this bacterium and the scope of disease that infection causes. Phylogenetic relationships and genomic diversity of 18 B. bacilliformis isolates (10 isolates from a region where Carrion's disease is epidemic, Cuzco, Peru, and 8 isolates from a region where Carrion's disease is endemic, Caraz, Peru) were assessed using genomic data generated by infrequent restriction site PCR and gene sequence analysis of the flagellin gltA and ialB genes. A population genetic analysis of the genomic diversity suggests that what was once considered an epidemic region of Peru did not result from the recent introduction of B. bacilliformis.

Epidemiology of endemic Bartonella bacilliformis: a prospective cohort study in a Peruvian mountain valley community.

Bartonella bacilliformis has caused debilitating illness since pre-Incan times, but relatively little is known about its epidemiology. A population-based, prospective cohort investigation was conducted in a Peruvian community with endemic bartonellosis. By use of house-to-house and hospital surveillance methods, cohort participants were monitored for evidence of bartonellosis. Of 690 participants, 0.5% had asymptomatic bacteremia at study initiation. After 2 years of follow-up, the incidence of infection was 12.7/100 person-years. The highest rates were in children <5 years old, and there was a linear decrease in incidence with increasing age. Seventy percent of cases were clustered in 18% of households. Age and bartonellosis in a family member were the best predictors of B. bacilliformis infection. There were multiple clinical presentations and significant subclinical infection. A cost-effective control strategy should include vector control and surveillance efforts focused on children and clusters of households with highest endemicity.