Laboratory diagnosis of mange-causing mites in dogs using a modified centrifugation-flotation technique in sucrose solution

Among the skin disorders of dogs, scabies is notable for its high occurrence rate and the need for veterinary interventions. There are two obstacles to making this diagnosis through direct investigation under a microscope (DIM): the continual need to make new slides when the results are negative and the long time needed for reading these slides. Thus, the objective of the present study was to compare efficacy between DIM and the technique of centrifugation-flotation in sucrose solution (CFSS) in samples from dogs in the semiarid region of the state of Paraíba, Brazil. Samples from 136 dogs were used, and three slides were made for each examination (DIM and CFSS). The readings were halted in cases of positivity. Positive samples were obtained from 56.6% of the dogs (77/136), of which 76.6% (59/77) were positive through both techniques, 13% (10/77) only through DIM and 10.4% (8/77) only through CFSS. The positivity rate did not differ statistically between the techniques. CFSS showed higher quality of readings, due to the considerably fewer artifacts on the slides, thereby optimizing the reading time. Sensitivity (85.6%), specificity (88.1%), accuracy (86.8%), positive predictive value (88.1%) and negative predictive value (85.1%) were obtained and the kappa coefficient (0.73) was considered substantial. It was concluded that CFSS showed high diagnostic capacity for scabies, similar to that of DIM, with optimized reading time, fewer artifacts and better display of mites.

     

Males mate indiscriminately in the tropical jumping spider Hasarius adansoni (Audouin, 1826)

Traditionally, sexual selection has been seen as a process in which choosy females select non‐choosy males. Recent studies, however, have challenged this view by showing that males can also be choosy in many species. We assessed the sexual preferences in males of the tropical jumping spider Hasarius adansoni (Audouin, 1826). We measured mating effort in males and determined how female quality influences offspring quality, quantity, and survival. We also estimated total sperm load and how much sperm was invested in a mating with a particular female. We found no evidence of male mating effort in terms of mating frequency nor sperm investment. Similarly, there was no relationship between female quality (i.e., size and condition) and offspring quality (i.e., survival and feeding performance) or quantity. We found strong evidence that the sperm invested in a particular female is a function of the amount of sperm the male had available for usage at that particular mating. The fact that males probably find females sequentially, along with the lack of relationship between female quality and offspring quality/quantity, likely explains the lack of differences in mating effort by males.     

Paracoccidioidomycosis due to Paracoccidioides brasiliensis S1 associated with acquired immunodeficiency syndrome: A case report

BackgroundParacoccidioidomycosis (PCM) is an endemic disease in Latin America. In immunocompetent hosts, PCM occurs in two main clinical forms: acute and chronic. However, in HIV-infected patients PCM may show up simultaneous manifestations of acute and chronic forms.Case reportWe present the case of a patient diagnosed with HIV who had disseminated skin lesions and generalized lymphadenopathy, as well as respiratory and central nervous system involvement. The PCM diagnosis was confirmed by direct KOH examination, double immunodiffusion and the isolation of the fungus in samples of an abscess in the subcostal region. The isolate was identified as Paracoccidioides brasiliensis S1 by species-specific PCR using primers for protein-coding gene GP43 (exon 2) followed by PCR-RFLP of the alpha-tubulin gene.ConclusionsThere are few data in literature reporting species-specific molecular identification of Paracoccidioides in HIV/PCM patients. Therefore, this case report may contribute to improve the knowledge about this severe disease, its causative cryptic species, and its consequences to patients.     

Breakdown of green and senescent leaves in Amazonian streams: a case study

Limnology - Allochthonous organic matter in low-order streams is, in general, mainly composed of senescent leaves. However, in tropical streams green leaves can represent an important source of...     

Mechanisms underlying host persistence following amphibian disease emergence determine appropriate management strategies

Emerging infectious diseases have caused many species declines, changes in communities and even extinctions. There are also many species that persist following devastating declines due to disease. The broad mechanisms that enable host persistence following declines include evolution of resistance or tolerance, changes in immunity and behaviour, compensatory recruitment, pathogen attenuation, environmental refugia, density‐dependent transmission and changes in community composition. Here we examine the case of chytridiomycosis, the most important wildlife disease of the past century. We review the full breadth of mechanisms allowing host persistence, and synthesise research on host, pathogen, environmental and community factors driving persistence following chytridiomycosis‐related declines and overview the current evidence and the information required to support each mechanism. We found that for most species the mechanisms facilitating persistence have not been identified. We illustrate how the mechanisms that drive long‐term host population dynamics determine the most effective conservation management strategies. Therefore, understanding mechanisms of host persistence is important because many species continue to be threatened by disease, some of which will require intervention. The conceptual framework we describe is broadly applicable to other novel disease systems.     

γ-Lactones from Persea americana and Persea fulva – in Vitro and in Silico Evaluation of Trypanosoma cruzi Activity

In the present study, five known γ-lactones (majoranolide B – 1 , majorenolide – 2 , majorynolide – 3 , lincomolide D – 4 , and isolinderanolide E – 5 ), as well as a new one (perseanolide – 6 ), were isolated from Persea fulva and P. americana. All isolated compounds exhibited potential activity against trypomastigote forms of Trypanosoma cruzi, whereas compounds 2 (EC₅₀ of 4.8 μM) and 6 (EC₅₀ of 3.6 μM) displayed superior activity than the positive control benznidazole (EC₅₀ of 16.4 μM), with selectivity index (SI) values of 17.8 and >55.6, respectively (benznidazole, SI>12.2). Molecular docking studies were performed for 1 – 6 against six T. cruzi molecular targets. Using this approach, we observed that, even though perseanolide ( 6 ) showed favorable docking to several studied targets, the results were especially promising for hypoxanthine phosphoribosyl transferase (PDB 1TC1). As PDB 1TC1 is associated to the transference of a monophosphorylated ribose from phosphoribosylpyrophosphate (PRPP) in the ribonucleotide synthesis pathway, this interaction may affect the survival of T. cruzi in mammalian cells. The data herein also indicate that possible intermolecular interactions between 6 and PDB 1TC1 derive from (i) hydrogen bonds in the α,β-unsaturated-γ-lactone unity and (ii) hydrophobic interactions in the long-chain alkyl group. Based on our results, perseanolide ( 6 ), reported for the first time in this work, can auspiciously contribute to future works regarding new trypanocidal agents.     

Effects of the utilization of homeopathic elements in commercial diluent on swine sperm viability

It has been speculated that the homeopathic treatment of sperm cells in order to improve semen quality could be promising. However, few data is available and its use in spermatozoa requires investigation. It is well established that mitochondrial membrane potential is an important viability parameter of spermatozoa and it is intimately related to reproductive efficiency. In this manner, new technologies in order to improve the activity of sperm cells and, finally, the fecundity of swine herds are of extremely importance. Due to the lack of knowledge of homeopathic treatment effect on spermatozoa, the aim of the present study was to verify the effect of three different homeopathic treatments on viability of boar sperm cells. Three homeopathic treatments composed by Pulsatila CH6, Pulsatila and Avena CH6, Avena CH6 and one control treatment (sucrose) were added to diluted boar semen, which were cooled for 24 or 48 h. Interestingly, no positive effect of homeopathic treatments was observed over semen viability. However, it was demonstrated that the 24 h of cooling storage provided more viable sperm cells when compared to the 48-h period. This effect of storage period on sperm viability was assessed by intact plasmatic membrane, intact acrosome and mitochondrial membrane potential evaluation.     

Genotoxicity biomonitoring of sewage in two municipal wastewater treatment plants using the Tradescantia pallida var. purpurea bioassay

The genotoxicity of untreated and treated sewage from two municipal wastewater treatment plants (WTP BN and WTP SJN) in the municipality of Porto Alegre, in the southern Brazilian state of Rio Grande do Sul, was evaluated over a one-year period using the Tradescantia pallida var. purpurea (Trad-MCN) bioassay. Inflorescences of T. pallida var. purpurea were exposed to sewage samples in February (summer), April (autumn), July (winter) and October (spring) 2009, and the micronuclei (MCN) frequencies were estimated in each period. The high genotoxicity of untreated sewage from WTP BN in February and April was not observed in treated sewage, indicating the efficiency of treatment at this WTP. However, untreated and treated sewage samples from WTP SJN had high MCN frequencies, except in October, when rainfall may have been responsible for reducing these frequencies at both WTPs. Physicochemical analyses of sewage from both WTPs indicated elevated concentrations of organic matter that were higher at WTP SJN than at WTP BN. Chromium was detected in untreated and treated sewage from WTP SJN, but not in treated sewage from WTP BN. Lead was found in all untreated sewage samples from WTP SJN, but only in the summer and autumn at WTP BN. These results indicate that the short-term Trad-MCN genotoxicity assay may be useful for regular monitoring of municipal WTPs.