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Aim: To determine whether in vitro experimental conditions dictate cellular activation of the inflammasome by apatitic calcium phosphate nanoparticles., Material & Methods: The responses of blood-derived primary human cells to in situ-formed apatite were investigated under different experimental conditions to assess the effect of aseptic culture, cell rest and duration of particle exposure. Cell death and particle uptake were assessed, while IL-1β and caspase 1 responses, with and without lipopolysaccharide prestimulation, were evaluated as markers of inflammasome activation., Results: Under carefully addressed experimental conditions, apatitic nanoparticles did not induce cell death or engage the inflammasome platform, although both could be triggered through artefacts of experimentation., Conclusion: In vitro studies often predict that engineered nanoparticles, such as synthetic apatite, are candidates for inflammasome activation and, hence, are toxic. However, the experimental setting must be very carefully considered as it may promote false-positive outcomes.

Iron deficiency is the most common nutritional disorder worldwide with substantial impact on health and economy. Current treatments predominantly rely on soluble iron which adversely affects the gastrointestinal tract. We have developed organic acid-modified Fe(III) oxo-hydroxide nanomaterials, here termed nano Fe(III), as alternative safe iron delivery agents. Nano Fe(III) absorption in humans correlated with serum iron increase (P < 0.0001) and direct in vitro cellular uptake (P = 0.001), but not with gastric solubility. The most promising preparation (iron hydroxide adipate tartrate: IHAT) showed ~80% relative bioavailability to Fe(II) sulfate in humans and, in a rodent model, IHAT was equivalent to Fe(II) sulfate at repleting haemoglobin. Furthermore, IHAT did not accumulate in the intestinal mucosa and, unlike Fe(II) sulfate, promoted a beneficial microbiota. In cellular models, IHAT was 14-fold less toxic than Fe(II) sulfate/ascorbate. Nano Fe(III) manifests minimal acute intestinal toxicity in cellular and murine models and shows efficacy at treating iron deficiency anaemia., From the Clinical Editor: This paper reports the development of novel nano-Fe(III) formulations, with the goal of achieving a magnitude less intestinal toxicity and excellent bioavailability in the treatment of iron deficiency anemia. Out of the tested preparations, iron hydroxide adipate tartrate met the above criteria, and may become an important tool in addressing this common condition., (Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.)

The 2-5 nm Fe(III) oxo-hydroxide core of ferritin is less ordered and readily bioavailable compared to its pure synthetic analogue, ferrihydrite. We report the facile synthesis of tartrate-modified, nano-disperse ferrihydrite of small primary particle size, but with enlarged or strained lattice structure (~2.7Å for the main Bragg peak versus 2.6Å for synthetic ferrihydrite). Analysis indicated that co-precipitation conditions can be achieved for tartrate inclusion into the developing ferrihydrite particles, retarding both growth and crystallization and favoring stabilization of the cross-linked polymeric structure. In murine models, gastrointestinal uptake was independent of luminal Fe(III) reduction to Fe(II) and, yet, absorption was equivalent to that of ferrous sulphate, efficiently correcting the induced anemia. This process may model dietary Fe(III) absorption and potentially provide a side effect-free form of cheap supplemental iron. From the clinical editor: Small size tartrate-modified, nano-disperse ferrihydrite was used for efficient gastrointestinal delivery of soluble Fe(III) without the risk for free radical generation in murine models. This method may provide a potentially side effect-free form iron supplementation., (Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.)

The ferritin core is composed of fine nanoparticulate Fe(3+) oxohydroxide, and we have developed a synthetic mimetic, nanoparticulate Fe(3+) polyoxohydroxide (nanoFe(3+)). The aim of this study was to determine how dietary iron derived in this fashion is absorbed in the duodenum. Following a 4 wk run-in on an Fe-deficient diet, mice with intestinal-specific disruption of the Fpn-1 gene (Fpn-KO), or littermate wild-type (WT) controls, were supplemented with Fe(2+) sulfate (FeSO4), nanoFe(3+), or no added Fe for a further 4 wk. A control group was Fe sufficient throughout. Direct intestinal absorption of nanoFe(3+) was investigated using isolated duodenal loops. Our data show that FeSO4 and nanoFe(3+) are equally bioavailable in WT mice, and at wk 8 the mean ± SEM hemoglobin increase was 18 ± 7 g/L in the FeSO4 group and 30 ± 5 g/L in the nanoFe(3+) group. Oral iron failed to be utilized by Fpn-KO mice and was retained in enterocytes, irrespective of the iron source. In summary, although nanoFe(3+) is taken up directly by the duodenum its homeostasis is under the normal regulatory control of dietary iron absorption, namely via ferroportin-dependent efflux from enterocytes, and thus offers potential as a novel oral iron supplement., (© FASEB.)

Despite their clinical relevance, few studies have addressed the epidemiology of methicillin-susceptible S. aureus (MSSA). In particular, it is not clear how MSSA population structure has evolved over time and how it might have been shaped by the emergence of MRSA in the community (CA-MRSA). In the present study we have evaluated the MSSA population structure over time, its geographical distribution and relatedness with MRSA in Portugal. A total of 465 MSSA from infection and colonization, collected over a 19-year period (1992-2011) in the northern, central and southern regions of Portugal were analyzed. Isolates were characterized by spa typing and multilocus-sequence typing (MLST). Isolates with predominant spa types were characterized by pulsed-field gel electrophoresis (PFGE). Isolates relatedness was analyzed by eBURST and BURP. The 172 spa types found among the 465 MSSA were grouped into 18 spa-CC (clonal complexes). Ten clonal types were more prevalent (40 %): one major clone (ST30-t012) was present in the entire study period and all over the country and the other nine were intermittently detected over time (ST5-t002, ST8-t008, ST15-t084, ST34-t166, ST72-t148, ST1-t127, ST7-t091, ST398-t571 and ST34-t136). Interestingly, three MSSA clonal types observed only after 1996 were closely related with CA-MRSA epidemic strains (ST8-t008, ST72-t148 and ST1-t127) found currently in Portugal. The MSSA population in Portugal is genetically diverse; however, some dominant clonal types have been established and widely disseminated for almost two decades. We identified MSSA isolates that were related with emergent CA-MRSA clones found in Portugal.

Information on global human movement patterns is central to spatial epidemiological models used to predict the behavior of influenza and other infectious diseases. Yet it remains difficult to test which modes of dispersal drive pathogen spread at various geographic scales using standard epidemiological data alone. Evolutionary analyses of pathogen genome sequences increasingly provide insights into the spatial dynamics of influenza viruses, but to date they have largely neglected the wealth of information on human mobility, mainly because no statistical framework exists within which viral gene sequences and empirical data on host movement can be combined. Here, we address this problem by applying a phylogeographic approach to elucidate the global spread of human influenza subtype H3N2 and assess its ability to predict the spatial spread of human influenza A viruses worldwide. Using a framework that estimates the migration history of human influenza while simultaneously testing and quantifying a range of potential predictive variables of spatial spread, we show that the global dynamics of influenza H3N2 are driven by air passenger flows, whereas at more local scales spread is also determined by processes that correlate with geographic distance. Our analyses further confirm a central role for mainland China and Southeast Asia in maintaining a source population for global influenza diversity. By comparing model output with the known pandemic expansion of H1N1 during 2009, we demonstrate that predictions of influenza spatial spread are most accurate when data on human mobility and viral evolution are integrated. In conclusion, the global dynamics of influenza viruses are best explained by combining human mobility data with the spatial information inherent in sampled viral genomes. The integrated approach introduced here offers great potential for epidemiological surveillance through phylogeographic reconstructions and for improving predictive models of disease control.

Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Dietary non-heme iron contains ferrous [Fe(II)] and ferric [Fe(III)] iron fractions and the latter should hydrolyze, forming Fe(III) oxo-hydroxide particles, on passing from the acidic stomach to less acidic duodenum. Using conditions to mimic the in vivo hydrolytic environment we confirmed the formation of nanodisperse fine ferrihydrite-like particles. Synthetic analogues of these (~ 10 nm hydrodynamic diameter) were readily adherent to the cell membrane of differentiated Caco-2 cells and internalization was visualized using transmission electron microscopy. Moreover, Caco-2 exposure to these nanoparticles led to ferritin formation (i.e., iron utilization) by the cells, which, unlike for soluble forms of iron, was reduced (p=0.02) by inhibition of clathrin-mediated endocytosis. Simulated lysosomal digestion indicated that the nanoparticles are readily dissolved under mildly acidic conditions with the lysosomal ligand, citrate. This was confirmed in cell culture as monensin inhibited Caco-2 utilization of iron from this source in a dose dependent fashion (p<0.05) whilet soluble iron was again unaffected. Our findings reveal the possibility of an endocytic pathway for acquisition of dietary Fe(III) by the small intestinal epithelium, which would complement the established DMT-1 pathway for soluble Fe(II).

We report the direct detection of two metastable H(2^{2}S) atoms coming from the dissociation of a single cold H(2) molecule, in coincidence measurements. The molecular dissociation was induced by electron impact in order to avoid limitations by the selection rules governing radiative transitions. Two detectors, placed close to the collision center, measure the neutral metastable H(2(2)S) through a localized quenching process, which mixes the H(2^{2}S) state with the H(2^{2}P), leading to a Lyman-α detection. Our data show the accomplishment of a coincidence measurement which proves for the first time the existence of the H(2(2)S)-H(2(2)S) dissociation channel.

Novel aspects of engineered nanoparticles offer many advantages for optimising food products and packaging. However, their potential hazards in the gastrointestinal tract require further investigation. We evaluated the toxic and inflammatory potential of two types of particles that might become increasingly relevant to the food industry, namely SiO₂ and ZnO. The materials were characterised for their morphology, oxidant generation and hydrodynamic behaviour. Cytotoxicity and interleukin-8 mRNA and protein expression were evaluated in human intestinal Caco-2 cells. Particle pretreatment under simulated gastric and intestinal pH conditions resulted in reduced acellular ROS formation but did not influence cytotoxicity (WST-1 assay) or IL-8 expression. However, the differentiation status of the cells markedly determined the cytotoxic potency of the particles. Further research is needed to determine the in vivo relevance of our current observations regarding the role of particle aggregation and the stage of intestinal epithelial cell differentiation in determining the hazards of ingested particles.

Aims: Determine whether certain, natural phenolic compounds enhance activity of commercial antifungal drugs against yeast strains of Candida and Cryptococcus neoformans., Methods and Results: Twelve natural phenolics were examined for fungicidal activity against nine reference strains of Candida and one of C. neoformans. Six compounds were selected for synergistic enhancement of antifungal drugs, amphotericin B (AMB), fluconazole (FLU) and itraconazole (ITR). Matrix assays of phenolic and drug combinations conducted against one reference strain, each, of Candida albicans and C. neoformans showed cinnamic and benzoic acids, thymol, and 2,3- and 2,5-dihydroxybenzaldehydes (-DBA) had synergistic interactions depending upon drug and yeast strain. 2,5-DBA was synergistic with almost all drug and strain combinations. Thymol was synergistic with all drugs against Ca. albicans and with AMB in C. neoformans. Combinations of benzoic acid or thymol with ITR showed highest synergistic activity. Of 36 combinations of natural product and drug tested, none were antagonistic., Conclusions: Relatively nontoxic natural products can synergistically enhance antifungal drug activity, in vitro., Significance and Impact of the Study: This is a proof-of-concept, having clinical implications. Natural chemosensitizing agents could lower dosages needed for effective chemotherapy of invasive mycoses. Further studies against clinical yeast strains and use of animal models are warranted., (No claim to US Government works. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.)

A male patient from Guinea-Bissau was admitted to Egas Moniz Hospital, Lisbon, complaining of fever and exhibiting a productive cough with mucopurulent discharge and weight loss. He had been using empirical medication with dexamethasone to treat his generalized facial swelling. At admission, he was cachectic and presented with soft facial edema, oropharyngeal thrush, and two fistulas of the palate. Acid-fast bacilli were detected in the sputum and were later identified as Mycobacterium tuberculosis. Cultures of the palatine exudate and biopsy resulted in the growth of Candida albicans. The patient was administered antituberculosis drugs and fluconazole, but his clinical situation deteriorated progressively. Extensive investigation of his clinical condition did not result in a conclusive diagnosis until he began to experience respiratory distress and subcutaneous nodules appeared on his face. Biopsies of the hypopharynx and nodules revealed the presence of Conidiobolus coronatus. After initiating combined antifungal and antibiotic therapy, the patient's clinical condition improved significantly. We report an unusual presentation of entomophthoromycosis and describe the clinical difficulties that delayed this diagnosis.

The aim of this study was to develop a PCR-based method of gene-directed multiplex PCR to rapidly identify microcystins producing cyanobacteria, regardless of their taxa, that could be applied in routine freshwater monitoring. Instead of using the amplification of only one or two mcy gene fragments, a multiplex PCR that simultaneously amplifies mcyA-cd, mcyAB, and mcyB fragments of the microcystin gene cluster was validated with DNA from 124 cyanobacterial isolates and applied in 37 environmental samples. The toxicological status of the isolates was assessed by high-performance liquid chromatography also used as the "gold standard" for the evaluation of multiplex mcy genes-based PCR, where a sensitivity of 92.3% and a specificity of 100% have been obtained. For the environmental samples, a rapid protocol for their direct use in the PCR reaction has been developed and, by using ELISA results as "gold standard" for the presence of microcystins in these samples, a sensitivity of 80% and a specificity of 100% were achieved, showing that this multiplex PCR test is a rapid, reliable, and economical way of assessing the microcystin-producing potential of cyanobacteria in freshwaters, regardless of their taxa or microcystins variant produced., ((c) 2009 Wiley Periodicals, Inc.)

Humans have evolved with oral exposure to dietary microparticles and nanoparticles as a normal occurrence but the ever-growing exploitation of nanotechnology is likely to increase exposure further, both qualitatively and quantitatively. Moreover, unlike the situation with respirable particles, relatively little is known about gastrointestinal intake and handling of nanoparticles. With a long term interest in gut exposure and responses to dietary microparticles, our group is now applying its expertise to nanoparticles in the gastrointestinal tract. Here we aim to address (i) the current challenges associated with the characterisation of particle-host or particle-cell interactions, (ii) the origin and mechanisms of uptake of particles in the gastrointestinal tract, especially via the Peyer's patch and (iii) potential cellular effects of nanoparticles in the generation of reactive oxygen species and inflammasome activation, or microparticles in their adjuvant activity in pro-inflammatory signalling and immune responsiveness., (Copyright 2010 Elsevier Ltd. All rights reserved.)

We report here a simple entry into naphtho[2,3-d]isoxazole-4,9-dione system containing a EWG in position 3 using the readily available 2,3-dichloro-1,4-naphthoquinone and nitromethyl derivatives in the presence of base. Antifungal activity of synthesised naphthoquinones was evaluated against ATCC and PYCC reference strains of Candida. The results suggest that the naphtho[2,3-d]isoxazole-4,9-dione scaffold has the potential to be developed into novel and safe therapeutic antifungal agents., (Copyright 2009 Elsevier Ltd. All rights reserved.)

We carried out a cross-sectional study with analysis of the demographic, clinical and laboratory characteristics of patients with metal-on-metal hip resurfacing, ceramic-on-ceramic and metal-on-polyethylene hip replacements. Our aim was to evaluate the relationship between metal-on-metal replacements, the levels of cobalt and chromium ions in whole blood and the absolute numbers of circulating lymphocytes. We recruited 164 patients (101 men and 63 women) with hip replacements, 106 with metal-on-metal hips and 58 with non-metal-on-metal hips, aged < 65 years, with a pre-operative diagnosis of osteoarthritis and no pre-existing immunological disorders. Laboratory-defined T-cell lymphopenia was present in 13 patients (15%) (CD8(+) lymphopenia) and 11 patients (13%) (CD3(+) lymphopenia) with unilateral metal-on-metal hips. There were significant differences in the absolute CD8(+) lymphocyte subset counts for the metal-on-metal groups compared with each control group (p-values ranging between 0.024 and 0.046). Statistical modelling with analysis of covariance using age, gender, type of hip replacement, smoking and circulating metal ion levels, showed that circulating levels of metal ions, especially cobalt, explained the variation in absolute lymphocyte counts for almost all lymphocyte subsets.

In order to assess the potential of several molecular targets for the identification, typing and traceability of cyanobacteria in freshwater reservoirs, molecular techniques were applied to 118 cyanobacterial isolates mostly sourced from Portuguese freshwater reservoirs and representative of three orders of cyanobacteria: Chroococcales (54), Oscillatoriales (15) and Nostocales (49). The isolates were previously identified by morphological methods and subsequently characterized by composite hierarchical cluster analysis of STRR and LTRR (short and long tandemly repeated repetitive sequences) PCR fingerprinting profiles. Representative isolates were selected from each cluster and their molecular identification, at the species level, was obtained or confirmed by phylogenetic positioning using 16S rRNA gene and rpoC1 phylogenies. A highly congruent association was observed between STTR- and LTRR-based clusters and taxonomic affiliation, revealing the usefulness of such PCR fingerprinting profiles for the identification of cyanobacteria. Composite analysis of hierarchical clustering of M13 and ERIC PCR fingerprints also appeared suitable for strain typing and traceability within a reservoir, indicating its potential for use in cyanobacterial monitoring, as a quality management control. Based on Simpson (D) and Shannon-Wiener (J') indices a high diversity was observed within all species, with Planktothrix agardhii showing the lowest diversity values (D=0.83; J'=0.88) and Aphanizomenon flos-aquae the highest ones (D=J'=0.99). A diagnostic key based on 16S-ARDRA, ITS amplification and ITS-ARDRA for identification purposes is also presented.

The purpose of this study was to characterise methicillin-resistant Staphylococcus aureus (MRSA) isolates from the Republic of Georgia, part of the former Soviet Union. Thirty-two non-duplicate MRSA isolates were collected in the period from May 2006 to February 2007. The patient data were analysed and the isolates were characterised by staphylococcal protein A (spa) typing, staphylococcal chromosome cassette mec (SCCmec) typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and the detection of Panton-Valentine leukocidin (PVL) genes. Only two closely related spa types were found; 29 isolates were of spa type 459 and three were t030. The spa types belonged to sequence type (ST) 239, clonal complex (CC) 8. All isolates were multiresistant, PVL-negative and harboured SCCmec type IIIA. Based on the molecular findings and PFGE, the isolates most closely resembled the pandemic Brazilian clone (ST239-IIIA).

A cup inclination angle greater than 45 degrees is associated with increased wear rates of metal on polyethylene (MOP) hip replacements. The same maybe true for metal on metal (MOM) hips yet this has not been clearly shown. We measured the acetabular inclination angle from plain radiographs, and whole blood metal ion levels using Inductively Coupled Plasma Mass Spectrometry of 26 patients (mean Harris Hip Score 94 and mean time post op of 22 months) with Birmingham Hip Resurfacings. We identified a threshold level of 50 degrees cup inclination. Below this threshold, the mean whole blood cobalt and chromium were 1.6 ppb and 1.88 ppb respectively; above this threshold, the mean blood cobalt and chromium were 4.45 ppb and 4.3 ppb respectively. These differences were significant cobalt (p<0.01) and chromium (p=0.01). All patients above the threshold had metal levels greater than any of the patients below the threshold. For 14 patients, who returned one year later for a repeat blood metal level measurement, cobalt and chromium levels were very similar. The effect of an acetabular inclination angle of greater than 50 degrees on wear rates of MOM hips, as measured through blood metal ion levels, appears to be similar to that seen with MOP hips. Additionally, our new analytical methods may allow blood metal levels to be used as a realistic biomarker of in vivo wear rate of MOM hips. The implication is that metal levels can be minimised with optimal orientation of the acetabular component.

Six clinical isolates of Enterobacter cloacae isolated in a Portuguese hospital, between April 1999 and November 2000, demonstrated resistance to almost all broad-spectrum cephalosporins, except to cefepime. These isolates were susceptible to quinolones and to aminoglycosides. Isoelectric focusing demonstrated production of beta-lactamases with pIs > 8.0 and by all six isolates, exhibiting a cephalosporinase phenotype. The results of pulsed field gel electrophoresis revealed that these isolates were genetically unrelated. The amino acid sequence of six AmpC beta-lactamases (Eclo1FF, Eclo6FF, Eclo9FF, Eclo10FF, Eclo11FF and Eclo15FF) shared 97-99% homology with the chromosomal AmpC beta-lactamase from E. cloacae P99 and 86-87% homology with those of two plasmid-mediated AmpC beta-lactamases, MIR-1 and ACT-1. This is the first report of chromosomal AmpC beta-lactamase production by E. cloacae isolates in a Portuguese hospital.

Purpose: To analyze the role of mental handicap as a possible source of lack of development of bladder control and to find out the chance of continence to advise future patients., Materials and Methods: The parents and relatives of 100 consecutive mentally handicapped patients were inquired by a personal interview. Questions included the age when they stopped using diapers, enuretic events, frequency, urgency and leakage episodes, urinary infections. Etiology of their mental problem was unknown in 34, perinatal anoxia in 17, Down syndrome in 15, phenylketonuria in 18 and others minors causes. The grade of mental deficiency were profound in 1, severe in 10, moderate in 39, mild in 33 and normal inferior value in 17. The age varied from 7 to 37 years old, with an average of 14 by the time of the interview, comprising 60 males and 40 females., Results: All profound and severe patients presented leakage episodes regardless of the age. The mild and normal inferior value acquired progressive urinary control with aging, and 33% still remain with urinary symptoms above 16 years old. Urinary infection was similar in males and females, around 29%. The most committed group presented less urinary infections. The etiology of the mental handicap was not correlated to the incidence of urinary leakage., Conclusions: The lack of bladder control was correlated to the grade of mental handicap. In severe and profound groups, the expectancy of control is disappointing. In the less compromised groups, there is a delay in bladder training, with achievement of control in (2/3) after 16 years of age. Those in the normal inferior value have a chance of postponed urinary control, easily misdiagnosed by normal urological interviews.

The most abundant decay channels have been studied quantitatively for high-energy (60 keV/amu) cluster ions H (3) (+)(H (2))(m = 1-14) colliding with He atoms employing a recently developed multicoincidence technique for the simultaneous detection of the correlated fragments on an event-by-event basis. This allows us to identify decay reactions and their underlying decay mechanisms responsible for the occurrence of the U-shaped fragmentation pattern.

This cross-sectional study among rural workers in the mountainous region of the southernmost Brazilian State of Rio Grande do Sul was designed to identify the characteristics of work performed on family farms. The research focused on the socio-demographic profiles of rural workers, identifying the characteristics of rural labor and describing the prevalence of some disease entities in such populations. Some 1479 rural workers from 495 farms were interviewed. In this sample, 87% of the individuals were members of the farm-owning family, mean age was 41 years, 56% were males, and mean schooling was 5 years. Farms had a mean area of 37 hectares, 50% had at least one type of farm machinery, and fruits constituted the main crop. About 75% of workers handled several types of pesticides, while 12% reported at least one lifetime episode of pesticide poisoning. Prevalence of minor psychiatric disorders was 36%, and annual frequency of occupational injuries was 10%. There was a wide variety of activities and occupational risks. The high prevalence of health problems identified in the study calls attention to the need for measures to promote and protect rural workers' health.

Objective: In view of the shortage of population-based rural studies, this research project evaluated the associations between the characteristics of rural work and the occurrence of minor psychiatric disorders (MPD)., Methods: A cross sectional study was carried out on the 1,282 farm workers of 446 farms. Information about the farms (land extension, agricultural activities, technology and pesticide use) was collected. Demographic and socioeconomic data, characteristics of the work process and mental health indicators were obtained from the workers., Results: MPD were found in 37.5% of the farm workers. The risk was higher on farms with a land extension of from 26 to 50 hectares, and lower where there was an increased level of job technology and schooling. The prevalence of MPD was higher among bean producers and lower among apple producers. Despite the impossibility of defining the direction of the causal link, pesticide poisoning was strongly associated with MPD., Conclusion: The results call attention to the dimension of the problem and to the importance of adopting new policies for the protection of farm workers' mental health.