State of art of robotic prostatectomy: How do we do in Catalonia, Spain

INTRODUCTION AND OBJECTIVE

Robotic-assisted laparoscopic prostatectomy (PLAR) seems to improve functional outcomes, however there is not a consensus of a standard procedure. The aim of this study was to identify the PLAR "state of art" in Catalonia, Spain.

MATERIAL AND METHODS

This was a cross-sectional survey-based study conducted among urologists across Catalonia, Spain. The survey was distributed through online platforms and the professional urology society. All statistical analyses were performed using Stata software, v20.

RESULTS

59 urologists completed the survey, revealing PLAR as the most commonly used technique (79.7%). Most urologist (70%) create the pneumoperitoneum using a controlled incision with direct access and 78.3% use the Airseal technology. The intraperitoneal approach is performed in >90% of cases. Endopelvic fascia preservation is not routinely performed. 34.5% of the survey not perform the dorsal vein complex suture. All preserves the bladder neck when oncologically safe. Nerve-vascular bundles bleeding control is performed using standard coagulation or suturing. 34% performed posterior reconstruction. Only use hemostatic devices when evident bleeding and 70% does not routinely left a drainage. Multivariable analysis showed that center volume had a significant independent association with dorsal venous complex suturing (OR 0.073, 95%CI 0.07-0.826), nerve-vascular bundles suturing hemostasis (OR 11.67, 95%CI 1.07-127.60) and endopelvic fascia preservation (OR 13.64, 95%CI 1.087-201.27), but there was no correlation with time the bladder catheter or days hospitalized.

CONCLUSIONS

The study provides an overview of the state of PLAR in Catalonia, Spain, showing significant variability and reflecting a commitment to advancing surgical technology and patient care.

Systematic review of methods used to improve the efficacy of magnetic resonance in early detection of clinically significant prostate cancer

BACKGROUND AND OBJECTIVE

Prostate cancer (PC) is the malignant neoplasm with the highest incidence after lung cancer worldwide. The objective of this study is to review the literature on the methods that improve the efficacy of the current strategy for the early diagnosis of clinically significant PC (csPC), based on the performance of magnetic resonance imaging (RM) and targeted biopsies when suspicious lesions are detected, in addition to systematic biopsy.

EVIDENCE ACQUISITION

A systematic literature review was performed in PubMed, Web of Science and Cochrane according to the PRISMA criteria (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), using the search terms: multiparametric magnetic resonance imaging, biparametric magnetic resonance imaging, biomarkers in prostate cancer, prostate cancer y early diagnosis. A total of 297 references were identified and, using the PICO selection criteria, 21 publications were finally selected to synthesize the evidence.

EVIDENCE SYNTHESIS

With the consolidation of MRI as the test of choice for the diagnosis of prostate cancer, the role of PSA density (PSAD) becomes relevant as a predictive tool included in prediction nomograms, without added cost. PSAD and diagnostic markers, combined with MRI, offer a high diagnostic power with an area under curve (AUC) above 0.7. Only the SHTLM3 model integrates markers in the creation of a nomogram. Prediction models also offer consistent efficacy with an AUC greater than 0.8 when associating MRI.

CONCLUSIONS

The efficacy of MRI in clinically significant prostate cancer detection can be improved with different parameters in order to generate predictive models that support decision making.

Continence definition and prognostic factors for early urinary continence recovery in posterior rhabdosphincter reconstruction after robot-assisted radical prostatectomy. Post-hoc analysis of a randomised controlled trial

INTRODUCTION

Urinary incontinence after radical prostatectomy (RP) is an adverse event with high impact on patient's quality of life. Nowadays there is no standardized method for urinary continence measurement. Posterior rhabdosphincter reconstruction (PRR) is a surgical step that can improve early urinary continence after RP. Our objective was to analyse different continence definitions and predictors of urinary continence recovery after robot-assisted RP (RARP).

MATERIAL AND METHODS

We conducted a double-blind, randomised controlled trial (NCT03302169) including 152 consecutive patients with localized prostate cancer subjected to RARP. Patients were randomised to single urethrovesical anastomosis (control arm) or PRR before urethrovesical anastomosis (PRR arm). Urinary continence was measured with the EPIC-26 and ICIQ-SF validated questionnaires, and pad use (0-1 pads and no pads), at 7, 15, 30, 90, 180 and 365 days after catheter removal. Prognostic factors for early urinary continence recovery were analysed.

RESULTS

72 patients were included in the control arm and 80 in the PRR arm. Baseline characteristics were similar between arms, except body mass index, which was higher in PRR arm. "No pad" was the only definition assessing the benefit of PRR at 30 days, 33.8% in PRR arm and 18.1% in control arm, p = 0.022; and at 90 days, 58.8 and 43.1% respectively, p = 0.038. Questionnaires did not detect differences in terms of continence recovery. PRR was the only predictor for early continence recovery, p = 0.03.

CONCLUSIONS

PRR increased early urinary continence recovery after RARP. Continence definition was critical to assess benefit. The only predictive factor for early continence recovery was PRR.

The current value of histological findings in negative prostate biopsies to predict the future risk of clinically significant prostate cancer

BACKGROUND

Repeat prostate biopsy (PBx) is recommended under persistent suspicion of prostate cancer (PCa) or in the face of the following findings: atypical small acinar proliferation (ASAP); extense (≥3 biopsy sites) high-grade prostatic intraepithelial neoplasia (HGPIN); or HGPIN with atypical glands; suspicious for adenocarcinoma (PIN-ATYP). Nowadays; multiparametric magnetic resonance imaging (mpMRI) and mpMRI targeted PBx (MRI-TBx) are recommended in repeat PBx. Our objective was to analyze the current value of ASAP; mHGPIN; PIN-ATYP and other histological findings to predict clinically significant PCa (csPCa) risk.

METHODS

Retrospective analysis of 377 repeat PBxs. MRI-TBx was performed when Prostate Imaging-Reporting and Data System (PI-RADS) score >3 and 12-core transrectal ultrasound (TRUS) systematic PBx when ≤2. ASAP; HGPIN; mHGPIN; PIN-ATYP; and 8 other histological findings were prospectively reported in negative PBx. CsPCa was defined as ISUP group grade >2.

RESULTS

Incidence of ASAP; multifocal HGPIN (mHGPIN) and PINATYP was 4.2%; 39.7% and 3.7% respectively; and csPCa rate was statistically similar among men with these histological findings. However; the rate of csPCa was 22.2% when proliferative inflammatory atrophy (PIA) was present; and 36.1% when it was not. PIA was the only histological finding which predicted lower risk of csPCa; with an OR of 0.54 (95%CI: 0.308-0.945; P = .031). In addition; PIA was an independent predictor of a model combining clinical variables and mpMRI which reached area under de ROC curve of 0.86 (95%CI: 0.83-0.90).

CONCLUSION

PIA emerged as the only predictive histological finding of csPCa risk and can contribute to a predictive model. mHGPIN failed to predict csPCa risk. The low incidence of ASAP (4.2%) and PIN-ATYP (3.7%) prevented us from drawing conclusions.

Are targeted prostate biopsies ready to replace systematic prostate biopsies?

OBJECTIVES

To evaluate the efficacy and efficiency of systematic prostatic biopsy (SPB) and cognitive fusion PB (CFPB) to diagnose prostate cancer (PCa) and significant PCa (SPCa), and to analyse if CFPB could safely replace SPB.

MATERIAL AND METHODS

A cohort of 314 consecutive men having PI-RADS ≥2 in a pre-biopsy 3T mp-MRI were prospectively subjected to trans-rectal ultrasound CFPB (two cores per suspicious area until a maximum of three areas) and a 12 peripheral core SPB. SPCa was considered when the WHO grade was higher than 2 (Gleason 4+3 or higher).

RESULTS

PCa was diagnosed in 133 patients (42.4%), being 83 (62.4%) SPCa. SPB detected PCa in 114 men (85.7%) while CFPB in 103 (77.4%), P<.001. SPB detected SPCa in 64 men (77.1%) while CFPB in 71 (85.5%), P<.001. In 52 of the 81 men (64.2%) SPCa was detected in SPB and CFPB. In 19 men SPCa was only detected in CFPB (23.5%) while in 10, it was only detected in SPB (12.3%). 33.1 cores were needed to diagnose one PCa in SPB while 8.5 in CFPB, P<.001. 58.9 cores were needed to diagnose one SPCa in SPB, while 12.4 in CFPB, P<.001.

CONCLUSIONS

CFPB are more effective and also more efficient than SPBs in detecting SPCa. However, CFPBs still can't safely replace SPBs because they are not able to detect up to 15% of SPCa.

In Search for risk predictors at the microscopic scenario of a negative biopsy. A systematic review

INTRODUCTION

In cases of persistent suspicion of prostate cancer (PC), repeat prostate biopsies (PB) are frequently performed in spite of their low yield. In the context of a negative PB, there is a microscopic scenario (MS), which we define as the group of recognizable non-neoplastic lesions. While some of these lesions seem to have a protective effect, the existence of others increases the risk of PC detection in posterior PB. The objective of this systematic review is to identify the lesions that may belong to the MS of a negative PB and analyse the current evidence of their association with the risk of detecting PC in subsequent PBs.

EVIDENCE ACQUISITION

Two independent reviewers conducted a literature search on Medline, Embase and Central Cochrane with the following search terms: small acinar proliferation, ASAP, prostatic intraepithelial neoplasia, HGPIN, adjacent small atypical glands, pinatyp, atrophy, proliferative inflammatory atrophy, pia, prostatic inflammation, prostatitis and prostate cancer. 1,015 references were first identified, and 57 original articles were included in the study, following the PRISMA declaration and the PICO selection principles.

EVIDENCE SYNTHESIS

Atypical small acinar proliferation is associated with PC detection in repeat PB with rates ranging between 32 and 48%. High-grade prostatic intraepithelial neoplasia (HGPIN) is related to PC in 13 to 42% of cases. Studies show that HGPIN, when multifocal, is a significant independent risk factor for PC. Prostatic atrophy, inflammatory proliferative atrophy and prostatic inflammation seem to act as protective factors on the detection of PC in repeat PB. On the other hand, the risk of PC detection reduces significantly in male patients with multifocal HGPIN and coexistent PIA.

CONCLUSIONS

The MS of a negative PB may include atypical small acinar proliferation, HGPIN, prostatic atrophy, inflammatory proliferative atrophy and prostatic inflammation lesions, since they all seem to be associated with the risk of PC detection in repeat PB. This review has led us to create the hypothesis that the MS of a negative PB might be a valuable and useful tool when considering repeat PB.

Preoperative magnetic resonance imaging in predicting early continence recovery after robotic radical prostatectomy

INTRODUCTION AND AIMS

Urinary incontinence is a common complication after radical prostatectomy. The aim of our study was to describe the preoperative anatomical features using magnetic resonance imaging in order to predict early continence recovery after robotic radical prostatectomy.

MATERIAL AND METHODS

72 patients who underwent robotic radical prostatectomy were prospectively analysed. EPIC questionnaire (1, 6 and 12 mo) and first self-reported continence were used to assess functional outcomes. Membranous urethral length (MUL) and MUL-prostate axis angle (aMULP) were assessed preoperatively on T2 weighted sagittal images.

RESULTS

Continence rate was 67.2%, 92.6% and 95.2% at 1, 6 and 12 months, respectively. Early continence was achieved in patients with the lower aMULP. At 1 month, average aMULP in continent patients was 107.21° (IC 95% 90.3-124.6) vs. 118.5° (IC 95% 117.7-134) in incontinent ones (P=.014). At 6 month differences in aMULP among groups were found: 114.24° (IC 95% 104.6-123.9) in continents vs. 142° (IC 95% 126.5-157.6) in incontinents (P=0.015). At 12 month, continent group showed a significantly higher preoperative aMULP. aMULP was revealed as the only independent predictor of urinary continence at 6 mo in multivariate analysis, OR 0.007 (IC 95% 0.002-0.012), P=0.012.

CONCLUSIONS

Preoperative anatomical parameters assessment prior surgery can help to identified those patients will achieve early continence recovery and it supports therapeutic decisions making.

The role of STAT3 protein as a prognostic factor in the clear cell renal carcinoma. Systematic review

CONTEXT AND OBJECTIVE

There have been significant advances in the knowledge of renal carcinogenesis n the last years. Nowadays, renal tumors are classified according to their genetic profile and specific treatments based on the identification of therapeutic targets have also been developed. However, no prognostic markers have yet been identified. The aim of this review is to analyse literature that has evaluated the expression of the STAT3 protein as a molecular marker in clear cell renal carcinoma (ccRCC).

EVIDENCE ACQUISITION

In January 2018 a systematic review was conducted in Pubmed, Cochrane library and Sciencedirect databases, from papers published from 1990. Search terms were"renal cell carcinoma"and"STAT3"or"STAT-3"and"prognostic factor. Following the principles of the PRISMA declaration and the PICO selection strategy, original articles with series of patients diagnosed with localized or metastatic ccRCC, and where the activity of STAT3 is analysed as a prognostic marker, were selected. A total of 132 publications were identified, of which 10 were finally revised, for they met the inclusion criteria.

EVIDENCE SYNTHESIS

STAT3 activation (phosphorylation) through Ser727 is important during ccRCC development and progression. PSTAT3 expression seems to be a prognostic marker and an antiangiogenic-resistance marker in metastatic patients. There is little evidence as prognostic marker in patients with localized disease.

CONCLUSIONS

STAT3 (Ser 727) expression in the nucleus of the ccRCC cells can be a prognostic marker and an antiangiogenic-resistance marker. Current scientific evidence is limited and more studies are needed to demonstrate its usefulness.

A systematic review of methods for quantifying serum testosterone in patients with prostate cancer who underwent castration

BACKGROUND

The clinical practice guidelines recommend measuring serum testosterone in patients with prostate cancer (PC) who undergo castration. The serum testosterone concentration should be <50ng/dL, a level established by using a radioimmunoassay method. The use of chemiluminescent immunoassays (IA) has become widespread, although their metrological characteristics do not seem appropriate for quantifying low testosterone concentrations. The objective of this review is to analyse the methods for quantifying testosterone and to establish whether there is scientific evidence that justifies measuring it in patients with PC who undergo castration, through liquid chromatography attached to a mass spectrometry in tandem (LC-MSMS).

MATERIAL AND METHODS

We performed a search in PubMed with the following MeSH terms: measurement, testosterone, androgen suppression and prostate cancer. We selected 12 studies that compared the metrological characteristics of various methods for quantifying serum testosterone compared with MS detection methods.

RESULTS

IAs are standard tools for measuring testosterone levels; however, there is evidence that IAs lack accuracy and precision for quantifying low concentrations. Most chemiluminescent IAs overestimate their concentration, especially below 100ng/dL. The procedures that use LC-MSMS have an adequate lower quantification limit and proper accuracy and precision. We found no specific evidence in patients with PC who underwent castration.

CONCLUSIONS

LC-MSMS is the appropriate method for quantifying low serum testosterone concentrations. We need to define the level of castration with this method and the optimal level related to better progression of the disease.

Systematic review of renal carcinoma prognostic factors

CONTEXT AND OBJECTIVES

The natural history of renal cell carcinoma is heterogeneous. Some scenarios can be found in terms of clinical presentation, clinical evolution or type of recurrence (local/metastatic). The aim of this publication is to analyze the most important prognostic factors published in the literature.

EVIDENCE ACQUISITION

A literature review ob published papers was performed using the Pubmed, from first Motzer's classification published in 1999 to 2015, according to PRISMA declaration. Search was done using the following keywords: kidney neoplasm, kidney cancer, renal cell carcinoma, prognostic factors, mortality, survival and disease progression. Papers were classified according to level of evidence, the number of patients included and the type of study performed.

EVIDENCE SYNTHESIS

The evolution in the knowledge of molecular pathways related to renal oncogenesis and the new targeted therapies has left to remain obsolete the old prognostic models. It's necessary to perform a continuous review to actualize nomograms and to adapt them to the new scenarios.

CONCLUSIONS

Is necessary to perform a proper external validation of existing prognostic factors using prospective and multicentric studies to add them into the daily urologist clinical practice.

Measurement of serum testosterone during androgenic suppression in patients with prostate cancer: A systematic review

INTRODUCTION

Clinical practice guidelines recommend measuring serum testosterone (ST) during androgenic suppression (AS) to assess its efficacy and define castration resistance (CR). The objectives of this systematic review were to assess the level of scientific evidence that justify checking ST levels during AS, when to perform it and for what purpose.

MATERIAL AND METHODS

We performed a search in PubMed with the following mesh terms: androgen suppression, testosterone, and prostate cancer. The search was narrowed to original articles published in English.

RESULTS

We found 8 publications that analysed the clinical impact of ST concentrations during AS. In all of the series, ST was measured using chemiluminescent assays. However, only indirect methods based on liquid or gas chromatography for its extraction and subsequent quantification using mass spectrometry are recommended, especially for measuring low levels. The endpoints were specific survival and CR-free survival. Six studies were retrospective. The series were not uniform in terms of clinical stage, types of AS and ST assessment methods. In general, low ST levels (<20ng/dL or <32ng/dL) were related to longer CR-free survival. The measurements were performed every 3 or 6 months. Four studies confirmed the beneficial effect of adding bicalutamide when detecting microelevations above 50ng/dL.

CONCLUSIONS

The level of scientific evidence justifying the measurement of ST during AS is low, and the methods employed for quantifying ST levels are inadequate. However, we consider it useful to check ST levels during AS, and there appears to be an association between low ST levels and better disease outcomes. In the event of microelevations above 50ng/dL, we recommend the administration of bicalutamide.

Vector Surveillance for Dengue Virus Detection in the Archipelago of Fernando de Noronha, Brazil

Aedes aegypti (L.) has become an efficient vector of important arboviruses due to its anthropophilic and domiciliary behaviors. Since the 1980s, dengue affects thousands of people every year in Brazil; in Fernando de Noronha (FN), a touristic archipelago, dengue cases have occurred since 2001. Once Ae. aegypti populations are well established in the inhabited areas of FN, the threat of dengue or another arbovirus epidemic is continuously imminent. This study aimed to monitor the DENV serotypes in mosquito samples collected in FN, where at least one resident was clinically diagnosed as dengue patient. Entomological surveillance was conducted in 2011 and 2012. Mosquitoes were sorted by sex and location and were stored in pools. DENV detection was performed using polymerase chain reaction with reverse transcription (RT-PCR) and the Platelia Dengue NS1 Ag. RNA integrity was checked by RT-PCR using rpL8 primers, and the minimum infection rate (MIR) was calculated. In total, 339 pools were analyzed, and only one was positive (DENV-1) by Multiplex RT-PCR (MIR = 1.53). When considering only pools with RNA integrity, the MIR was 2.92. Using the Platelia kit, the MIR was 9.18 (considering all the pools) and 17.54 (only 140 pools with RNA integrity). Our results showed the importance of a constant entomological surveillance in that area, the need to improve storage and transportation protocols, and an endogenous control in the RT-PCR to avoid false-negative results. Finally, our study indicated that the NS1-Ag detection was the most sensitive method and should be used routinely for DENV surveillance in mosquitoes if the serotype identification is not required.

Behavior of total and free serum testosterone as a predictor for the risk of prostate cancer and its aggressiveness

CONTEXT

Serum testosterone is mostly bound to the sex hormone-binding globulin and albumin. A small metabolically active part is present in the form of free testosterone (FT). The relationship between serum total testosterone (TT) levels and prostate carcinogenesis is debated. Our hypothesis is that the serum FT concentration is more closely associated with the risk of prostate cancer (PC) and its aggressiveness than TT.

OBJECTIVE

To analyze the scientific evidence that relates serum TT and/or FT levels with the diagnosis of PC and its aggressiveness.

ACQUISITION OF EVIDENCE

A systematic review was conducted in PubMed up to January 2015 using the following mesh terms: prostate cancer, sex hormone, androgen, testosterone and free testosterone.

SYNTHESIS OF THE EVIDENCE

We found 460 publications, 124 of which were reviewed to analyze the evidence. The relationship between serum TT levels and the diagnosis of PC and its aggressiveness is highly heterogeneous. The variability in the design of the studies, the quantification methods and other variables could explain this heterogeneity. In a number of studies that evaluated the estimated or measured FT, the evidence remains equally conflicting.

CONCLUSIONS

Based on the current evidence, we cannot recommend the measurement of serum TT and/or TL levels for the diagnosis of PC or for assessing its aggressiveness.

Bone mass behavior after 1 year of different treatment strategies in prostate cancer patients subjected to androgen deprivation therapy

The aim of this study was to evaluate bone mass changes after 1 year of four different types of pharmacological intervention. Ninety-seven prostate cancer patients treated with androgen deprivation therapy, and severe osteopenia or osteoporosis were retrospectively studied. Patients were divided in four groups. Group 1: 28 patients treated with denosumab, Group 2: 24 patients treated with alendronate, Group 3: 24 patients with no antiresorptive treatment and Group 4: 21 patients previously treated with alendronate and switched to denosumab. Dual X-ray absorptiometry was performed at baseline and after 1 year. Bone mass changes at the L2-L4 lumbar spine, femoral neck and total hip were evaluated. No differences were found at baseline. After 1 year, men receiving denosumab or alendronate (Group 1 and 2) showed a significant bone mass increase at the lumbar spine (+2.4 and +5.0 %, respectively), while no significant changes were observed in Group 3 and 4. At the femoral neck, Group 1 and 2 patients showed a significant bone mass increase (+3.7 and +3.6 %, respectively), while no significant changes were observed in Group 3 and 4. At the total hip, we observed a significant bone mass increase in Group 1 (+2.9 %) and a significant bone mass loss in Group 3 patients (-1.9 %). No significant changes were observed in Group 2 and 4. Denosumab increased significantly bone mass in all three dual X-ray absorptiometry standard sites, while alendronate did not at total hip. No benefit was observed in men previously treated with alendronate who switched to denosumab treatment.

Patient-based dengue virus surveillance in Aedes aegypti from Recife, Brazil

BACKGROUND & OBJECTIVES

Dengue is currently one of the most important arthropod-borne diseases and may be caused by four different dengue virus serotypes (DENV-1 to DENV-4), transmitted mainly by Aedes aegypti (Diptera: Culicidae) mosquitoes. With the lack of a dengue vaccine, vector control strategies constitute a crucial mode to prevent or reduce disease transmission. In this context, DENV detection in natural Ae. aegypti populations may serve as a potential additional tool for early prediction systems of dengue outbreaks, leading to an intensification of vector control measures, aimed at reducing disease transmission. In Brazil, this type of surveillance has been performed sporadically by a few groups and has not been incorporated as a routine activity in control programs. This study aimed at detecting DENV in natural Ae. aegypti from Recife, Pernambuco, to check the circulating serotypes and the occurrence of transovarial transmission in local mosquito populations.

METHODS

From January 2005 to June 2006, mosquitoes (adults and eggs) were collected in houses where people with clinical suspicion of dengue infection lived at. RNA was extracted from pooled mosquitoes and RT-PCR was performed in these samples for detection of the four DENV serotypes.

RESULTS & CONCLUSION

Out of 83 pools of adult mosquitoes collected in the field, nine were positive for DENV: five for DENV-1, two for DENV-2 and two for DENV-3. From 139 pools of adult mosquitoes reared from collected eggs, there were 17 positive pools: three for DENV-1, 10 for DENV-2, and four for DENV-3. These results are discussed in the paper in regard to the local dengue epidemiological data. The conclusions clearly point to the informative power and sensitivity of DENV entomological surveillance and to the importance of including mosquito immature forms in this strategy.

In vitro IFN-gamma production by goat blood cells after stimulation with somatic and secreted Corynebacterium pseudotuberculosis antigens

Corynebacterium pseudotuberculosis is the causal agent of caseous lymphadenitis, a chronic illness that attacks goats and sheep characterized by pyogranulomas formation in lymph nodes and organs. Regarding the current knowledge of the pathogenesis of the caseous lymphadenitis, there is evidence that besides the humoral response the induction of a durable cellular response is fundamental for its control. In this sense, research on antigens of C. pseudotuberculosis that are capable to inducing cellular immunity is an important step for the development of diagnosis tests and more efficient vaccines. In the present study, the interferon-gamma production in cultures of whole blood from infected goats stimulated with secreted bacterial antigen or somatic antigen were used to evaluate the cellular response. The results demonstrated a significant difference in the ability of the two antigens to induce a cellular response. That is, IFN-gamma production was high with cells from infected animals in response to the secreted antigen while IFN-gamma production was low when somatic antigen was used. The concomitant use of these antigens with PWM also showed differences. That is, the secreted antigen increased the IFN-gamma production induced by PWM, while the somatic antigen seems not to have altered the response to PWM.

Genetic structure of natural populations of Aedes aegypti at the micro- and macrogeographic levels in Brazil

Genetic variation in 13 populations of Aedes aegypti from 3 regions of Brazil was compared using variation at 10 isozyme loci. Heterozygosities varied from 0.050 +/- 0.027 to 0.280 +/- 0.120, and a large genetic differentiation (F(ST) = 0.144) was observed among all populations. The largest within-regions differences were found between populations from the urban areas of northeast Brazil (F(ST) = 0.152). Ecological conditions are likely having an impact on the population structure of Ae. aegypti in the different regions of Brazil.

Cross-resistance between strains of Bacillus sphaericus but not B. thuringiensis israelensis in colonies of the mosquito Culex quinquefasciatus

Two colonies of Culex quinquefasciatus Say (Diptera: Culicidae) were selected with Bacillus sphaericus strains C3-41 and IAB59 in the laboratory for 13 and 18 generations; they attained 145,000- and 48.3-fold resistance, respectively, in comparison with a susceptible laboratory colony (SLCq) and showed very high levels of cross-resistance (8500- to 145,000-fold) to B. sphaericus strains C3-41, 1593, 2297 and 2362. They were relatively susceptible to B. sphaericus strains LP1-G and 47-6B (only 0.8- to 2.8-fold tolerance), with 24.8- to 48.3-fold cross-resistance to strain IAB59. B. sphaericus-resistant mosquito colonies remained highly susceptible to B. thuringiensis israelensis, suggesting that B.t.i. would be of value in the management of B. sphaericus-resistant Cx. quinquefasciatus colonies. The demonstration of low or no cross-resistance of two selected resistant Cx. quinquefasciatus colonies to IAB59, LP1-G and 47-6B strains of B. sphaericus and the finding of a major 49 kDa protein in these strains suggest that there is likely to be another mosquitocidal factor in the three strains.

[Prevalence of canine filariasis by Dirofilaria immitis and Dipetalonema reconditum in Maceió, Alagoas State, Brazil]

A survey on the prevalence of Dirofilaria immitis and Dipetalonema reconditum was conducted in 1,519 dogs from Maceió and two coastal areas in the State of Alagoas, Northeast Brazil, from 1995 to 1999, by testing for microfilariae in blood. All blood samples were from exclusively domiciled dogs with a known history, showing that the infections were autochthonous, confirming transmission of canine filariasis in these areas. In Greater Metropolitan Maceió, 15 (1.3%) microfilaremic dogs were detected with D. immitis and 15 (1,3%) with D. reconditum. In the southern coastal area there was an estimated prevalence of 12.7% for D. immitis. D. immitis and D. reconditum microfilaria were 298.1 micrometer and 249.2 micrometer long and 7.3 micrometer and 4.4 micrometer wide, respectively. A Witness immunotest that detects D. immitis antigen was used to confirm parasitological results and reveal occult dirofilariasis cases. Of the total 6,579 females examined, 8 (0.1%) Culex quinquefasciatus were observed to be naturally infected with D. immitis larvae. These results proved dirofilariasis transmission in Maceió and demonstrated D. reconditum in the same geographic area.

Evaluation of a new tablet formulation based on Bacillus thuringiensis sorovar. israelensis for larvicidal control of Aedes aegypti

The effect of sunlight on the efficacy and persistence of an experimental tablet formulation based on Bacillus thuringiensis sorovar. israelensis (C4P1) was evaluated against Aedes aegypti larvae under simulated field conditions. The initial mortality ranged from 93 to 100%, and the residual activity (> or = 70% mortality) recorded in containers exposed to sunlight or shade were, respectively, 13-35 days and 40-54 days. The results suggest that C4P1 can provide long-term larvicidal effect and operational advantages.

Bacteriological larvicides of dipteran disease vectors

The apparent success in vector control observed between 1950 and 1970 was followed by worldwide resistance to organosynthetic insecticides wherever they were used intensively. Insect resistance to one or more categories of insecticides has limited the effectiveness of these compounds, and their non-selective mode of action adversely affects non-target organisms. This scenario highlights the need for selective agents in integrated vector control programs. This article gives an overview of the main fundamental and applied research topics on entomopathogenic bacteria in relation to their role in vector control.

Impact of a 26-month Bacillus sphaericus trial on the preimaginal density of Culex quinquefasciatus in an urban area of Recife, Brazil

A field trial using the entomopathogen Bacillus sphaericus against Culex quinquefasciatus was conducted in a district of Recife, Brazil, an area with a high prevalence of lymphatic filariasis. In this urban area more than 2,500 Cx. quinquefasciatus breeding sites within a 1.2-km2 area were found and subsequently submitted to a long-term treatment with B. sphaericus. To evaluate the impact of treatment on the densities of Cx. quinquefasciatus preimaginal forms, 26 breeding sites, representative of the major site types found in that area, were monitored for 3 years. Parameters such as mean and maximum densities of larval population as well as the frequency of infested sites were recorded before, during, and after the trial. The level of each parameter was greatly reduced during the treatment period, particularly in the 2nd treatment year. A low density of Cx. quinquefasciatus was also maintained throughout the last year, in the absence of treatment. Analysis of the data reported here confirms B. sphaericus as a very effective larvicide against Cx. quinquefasciatus despite the optimal environmental conditions for mosquito proliferation in the urban area of Recife.

The use of bacterial larvicides in mosquito and black fly control programmes in Brazil

Bacillus spp. based larvicides are increasingly replacing, with numerous advantages, chemical insecticides in programmes for controlling black fly and mosquito populations. Brazil was among the pioneers in adopting Bacillus thuringiensis israelensis (B.t.i) to control black flies. However, the major current mosquito control programme in Brazil, the Programme for Eradication of Aedes aegypti launched in 1997, only recently decided to replace temephos by B.t.i based larvicides, in the State of Rio de Janeiro. In the last decade, works developed by research groups in Brazilian institutions have generated a significant contribution to this subject through the isolation of B. sphaericus new strains, the development of new products and the implementation of field trials of Bacillus efficacy against mosquito species under different environmental conditions.

Efficacy of Bacillus sphaericus in control of the filariasis vector Culex quinquefasciatus in an urban area of Olinda, Brazil

The efficacy of Bacillus sphaericus 2362 against Culex quinquefasciatus was tested in 1991-94 in a major Brazilian endemic zone for bancroftian filariasis. Continuous selection pressure against the mosquito population was sustained for 18 months through treatment of 2500 potential breeding sites occurring within a 5.7-km2 urban area in the Metropolitan Region of Recife. The impact of this control intervention was evaluated by comparing entomological indices with those from an untreated area. Application of the larvicide kept the Cx. quinquefasciatus population density significantly lower when compared to the untreated area, despite some operational difficulties. Adult densities remained lower for at least 5 months after spraying ceased. Pre-trial microfilaria rates from the untreated and operational area were 13.1% and 7.2%, respectively. A 60% reduction in human exposure to infective bites was recorded as a consequence of this vector population control.

Reversal of low-level resistance to Bacillus sphaericus in a field population of the southern house mosquito (Diptera:Culicidae) from an urban area of Recife, Brazil

A larval population of Culex quinquefasciatus Say from an urban area (Coque) of Recife, Brazil, submitted to selection with Bacillus sphaericus Neide for a 26-mo trial, was 10 times less susceptible to B. sphaericus and slightly more susceptible to Bacillus thuringiensis israelensis, compared with untreated populations. The low-level resistance to B. sphaericus was unstable in the absence of selection pressure. The LC50 of B. sphaericus to the Coque population declined gradually and attained a susceptibility level similar to that observed in a laboratory control colony 16 mo after the treatment period was interrupted. In parallel to the recovery of B. sphaericus susceptibility. Coque larvae also were as susceptible as laboratory larvae to B. thuringiensis israelensis.

Epidemiological study of bancroftian filariasis in Recife, northeastern Brazil

Wuchereria bancrofti in Pernambuco was first documented in 1952 (Azevedo & Dobbin 1952), and since then it has been reported in surveys carried out in selected areas of Recife. Several surveys were carried out from 1981 to 1991 by SUCAM. In the 1985 SUCAM's report the disease is considered under control. The CPqAM Filariasis Research Program was established in 1985 and a filarial survey was carried out in the town of Olinda, Greater Recife. In order to verify the real epidemiological situation, a study was conducted in the city of Recife. 21/36 of the Special Zones of Social Interest (ZEIS), were randomly selected for the present study. From 10,664 persons screened, 683 were positive and the prevalence rate for microfilaraemia (mf) varied from 0.6% to 14.9%. A mean mf prevalence of 6.5%, showed that the infection occurs in a wide geographic distribution in Greater Recife and that the intensity of transmission is a real and potential threat to public health in affected communities. Mf rate among males and females differed significantly. Due to the rapid increase in population, unplanned urban settlements, poor sanitary facilities and the favorable geographical conditions to the development of the vector, filariasis may actually be increasing in Recife.

Integrated control measures against Culex quinquefasciatus, the vector of filariasis in Recife

Integrated control measures against Culex quinquefasciastus have been implemented in a pilot urban area in Recife, Brazil. About 3,000 breeding sites found within the operational area were responsible for very high mosquito densities recorded during the pretrial period. Physical control measures have been applied to cess pits before starting a series of 37 treatments of the other sites with Bacillus sphaericus strain 2362, over 27 months. In spite of the difficulties due to environmental conditions, very significant reductions in preimaginal population of C. quinquefasciatus were achieved and, as a consequence, low adult mosquito densities were maintained for a relatively long period of time. Entomological and environmental data gathered in this pilot project can contribute to design an integrated mosquito control program in Recife city.

Secretory activity and endocrine regulation of male accessory glands in the blood-sucking bug Panstrongylus megistus (Hemiptera: Reduviidae)

The epithelial cells of Panstrongylus megistus male accessory glands (MAG) present ultrastructural characteristics of a secretory cell. Their secretory products are accumulated in the lumen of the four MAG lobes. During the first 8 days of adult life a strong secretion activity occurs, accumulating enough material to produce the first spermatophore. Cerebral neurosecretions as well as juvenile hormone are both involved in MAG secretory activity regulation. Juvenile hormone seems to be the responsible for the stimulation of most protein synthesis in male accessory glands. Cerebral neurosecretion seems to be necessary to stimulate juvenile hormone production and release by the corpus allatum. Furthermore, neurosecretion is required for some polypeptides synthesis by MAG. Although topic application of precocene II to adult males does not reproduce the same effects on MAG as does allatectomy, this compound causes strong reduction on male reproductive capacity.