First record of a new microsporidium pathogenic to Gonipterus platensis in Brazil.

Microsporidia are naturally occurring fungal-related parasites that can infect nearly all animal hosts, but their biocontrol potential of insect pests is routinely overlooked in agriculture and forestry. This research brings the first report describing the natural occurrence of a microsporidium causing disease in field-collected populations of the invasive eucalyptus snout beetle, Gonipterus platensis (Coleoptera: Curculionidae), a major destructive pest of eucalyptus plantations in Brazil. Adult beetles were collected during field surveys in commercial eucalyptus plantations in southern Brazil to be examined and dissected with typical symptoms to verify presence of microsporidian spores in haemolymph. From 14 plantations in different sites, the natural infection occurrence in these populations ranged from 0 to 65%, while a lab colony exhibited an infection incidence of 70%. Spore density in haemolymph of symptomatic insects averaged 2.1 (± 0.4) × 107 spores/beetle. Symptoms in infected adults were identified by an abnormal abdomen with malformation of the second pair of wings, impairing their flight activity. Electron transmission microscopy of the pathogen showed morphological features similar to species belonging to the genus Nosema or Vairimorpha. Phylogenetic analysis of the full-length small subunit ribosomal RNA gene suggests this pathogen's placement in the genus Vairimorpha, but with a sequence identity of ~ 94% with the nearest neighbours. The low level of sequence identity suggests this pathogen may represent a novel taxon in the genus and further requires whole genome sequencing for definitive taxonomic resolution. These findings provide insights on the natural occurrence of this novel pathogen of this invasive pest in Eucalyptus plantations in Brazil. Further studies are needed to determine potential of this microsporidium in the design of conservative or augmentative biological control programs for this invasive pest.

Entomopathogenic fungi as the microbial frontline against the alien Eucalyptus pest Gonipterus platensis in Brazil.

The eucalyptus snout beetle (ESB), Gonipterus platensis, is endemic to Australia but has become a major invasive, destructive pest of Brazilian eucalyptus plantations. Efforts to develop insecticides based on entomopathogenic fungi against ESB are limited by the lack of known virulent strains. We therefore explored the virulence of indigenous Brazilian strains of major entomopathogenic fungi-Beauveria spp. and Metarhizium anisopliae-against ESB adults. We found widely varying virulence and later capacities for conidial production on infected adult cadavers. Two strains stood out, B. bassiana IBCB-240 and M. anisopliae IBCB-364, as especially lethal for ESB adults under laboratory conditions, sporulated abundantly on infected insects, and also outperformed comparable strains used in commercial mycoinsecticides. Notably, B. bassiana IBCB-240 exhibited lower LT50 values at low inoculum levels (≤ 107 conidia mL-1) and smaller LC50 values than M. anisopliae IBCB-364. Taken together, this study emphasizes natural variation in virulence among indigenous Beauveria and Metarhizium strains against ESB adults and identifies fungal strains with superior lethality to existing commercialized strains for managing this eucalyptus pest in Brazil.

Identification and genome sequencing of RNA viruses in the eucalyptus snout beetle Gonipterus spp. (Coleoptera: Curculionidae).

The genomes of two putative new RNA viruses (macula-like virus and bunya-like virus) were identified in total RNA extracted from dead eucalyptus snout beetles (Gonipterus spp.) from a laboratory colony. However, only bunya-like virus was detected in field-collected insects. The macula-like virus has a monopartite single-stranded RNA genome that contains three open reading frames (ORFs) encoding an RNA-dependent RNA polymerase (RdRp), a capsid protein (CP), protein with unknown function. The bunya-like virus genome was predicted to consist of two RNA segments: a large segment (L) encoding a single protein (RdRp) and a small segment (S) encoding a putative nucleocapsid protein.

Determination of Oxytetracycline and 4-Epi-Oxytetracycline Residues in Feathers and Edible Tissues of Broiler Chickens Using Liquid Chromatography Coupled with Tandem Mass Spectrometry.

Antibiotics have been widely used in poultry production for the treatment of bacterial diseases. However, drug residues can remain in products derived from animals after the cessation of the drug therapies. Feathers, in particular, have shown an affinity for antibiotics such as tetracycline, suggesting the persistence of these drugs in nonedible tissue. After the birds are slaughtered, feathers are ground into feather meals, which are used as organic fertilizer or an ingredient in animal diets, thereby entering into the food chain and becoming a potential risk for public health. To evaluate the depletion of oxytetracycline (OTC) and its metabolite 4-epi-oxytetracycline (4-epi-OTC) in the muscles, liver, and feathers, 64 broiler chickens, bred under controlled conditions, were treated orally with a commercial formulation of 10% OTC for 7 days. The analytes were quantified using liquid chromatography-tandem mass spectrometry. OTC and 4-epi-OTC were found in the feathers for 46 days, whereas they were found in the muscle and liver for only 12 and 6 days, respectively. These results prove that the analytes remain in feathers in higher concentrations than they do in edible tissues after treatment with tetracyclines. Thus, feather meals represent a potential source of antimicrobial residue contamination in the food chain.

Withdrawal times of oxytetracycline and tylosin in eggs of laying hens after oral administration.

Antimicrobials administered to laying hens may be distributed into egg white or yolk, indicating the importance of evaluating withdrawal times (WDTs) of the pharmaceutical formulations. In the present study, oxytetracycline and tylosin's WDTs were estimated. The concentration and depletion of these molecules in eggs were linked to their pharmacokinetic and physicochemical properties. Twenty-seven Leghorn hens were used: 12 treated with oxytetracycline, 12 treated with tylosin, and 3 remained as an untreated control group. After completion of therapies, eggs were collected daily and drug concentrations in egg white and yolk were assessed. The yolk was used as the target tissue to evaluate the WDT; the results were 9 and 3 days for oxytetracycline and tylosin, respectively. In particular, oxytetracycline has a good oral bioavailability, a moderate apparent volume of distribution, a molecular weight of 460 g/mol, and is lightly liposoluble. Tylosin, a hydrosoluble compound, with a molecular weight of 916 g/mol, has a low oral bioavailability and a low apparent volume of distribution, too. Present results suggest that the WDTs of the studied antimicrobials are strongly influenced by their oral bioavailability, the distribution, and the molecular weight and solubility, and that these properties also influence the distribution between the egg yolk and white.

Comparison of integron-linked antibiotic resistance genes in strains of Salmonella spp. isolated from swine in Chile in 2005 and 2008.

Salmonella spp. isolates obtained from healthy swine in 2008 were analyzed for antibiotic resistance phenotypes and genotypes. The resistance profiles of the 2008 isolates were compared with those of a Salmonella collection isolated from the same geographical area in 2005. The 2008 isolates consisted of strains that were 97% oxytetracycline resistant, 33.3% amoxicillin resistant, 31.8% amoxicillin- plus clavulanic acid resistant, 27.5% trimethoprim-sulfamethoxazole resistant, 17.3% streptomycin resistant, and 7.2% enrofloxacin-ciprofloxacin resistant. The presence of integrons and resistance genes and their topological association in resistant strains was assessed by PCR. The prevalence of class 1 integrons was the highest, at 46.2%, while class 2 integrons were present in 17.9% of the isolates. In strains that harboured class 1 integrons, we identified 3 different gene cassette arrangements; a single class 2 integron arrangement of dfrA1-sat1-aadA1 was found. Comparison of these results with data obtained from the 2005 isolates showed that Salmonella strains resistant to amoxicillin and amoxicillin plus clavulanic acid had clearly emerged over the span of 3 years, along with an increase in the prevalence of class 1 integrons and the acquisition of new gene cassette arrangements. These findings highlight the need for continual monitoring of regional isolates to establish more efficient vigilance programs that can address variations in resistance over short periods of time within the same geographical area.

Retention strategies and predictors of attrition in an urban pediatric asthma study.

BACKGROUND: The Urban Environment and Childhood Asthma (URECA) study is a multicenter prospective birth cohort study designed to examine factors related to the development of childhood asthma and allergies in an inner-city population. The retention of these participants has been challenging due to high mobility, inconsistent phone service, custody issues, and stressful life situations. PURPOSE: In this article, we describe the specific retention challenges we encountered during the first 2 years of follow-up in URECA and the strategies we utilized to address them. We also examine how selected maternal characteristics and other factors are related to retention and missed study visits. METHODS: Strategies implemented to engage participants included: collecting updated and alternative contact information, after-hours phone calls to participants, culturally competent staff, flexible study event scheduling, clinic visit transportation, quarterly newsletters, retention events, drop-in home visits, and cell phone reimbursements. An internally developed web-based data management system enabled close monitoring by site teams and the coordinating center. The rate of deactivations was calculated using survival analysis. Characteristics of active and deactivated participants were compared using the chi-squared test with a Cochran-Mantel - Haenszel adjustment for study site. The proportion of missed visits of the total expected in the first 2 years was calculated and compared by family characteristics using an ANOVA model or a trend test controlling for study site. All analyses were performed using SAS version 9.1 (Cary, NC). RESULTS: The 2-year retention rate was 89%. Participation in the first study event predicted subsequent engagement in study activities. Mothers who did not complete the first visit were more likely to miss future events (46.1% vs. 8.9%, p<0.0001) and to be deactivated (38.5% vs. 4.5%, p<0.0001). Mothers under 18 years of age were more likely to leave the study compared to older mothers (22.7% vs. 10.1%, p = 0.02). Also, mothers who were married missed fewer events than those not married (8.8% vs. 15.6%, p = 0.01). In addition, deactivations were more common when the child had entered daycare by 3 months of age (10.9% vs. 3.6%, p = 0.05). LIMITATIONS: The URECA population is predominantly minority, thus our findings might not be generalizable to other populations. Furthermore, we may not be able to observe the effects that might exist in a more diverse population. For example, 86% of the mothers are unmarried, making it difficult to reliably examine the effect of marital status. CONCLUSION: In research, successfully engaging and retaining participants is essential for achieving the study objectives. Identifying factors related to missed visits and deactivations are the initial step in recognizing the potential at-risk participants and can enable the design of targeted strategies to retain participants.