Predicting severity of asian soybean rust epidemics with empirical rainfall models.

ABSTRACT Although Asian soybean rust occurs in a broad range of environmental conditions, the most explosive and severe epidemics have been reported in seasons with warm temperature and abundant moisture. Associations between weather and epidemics have been reported previously, but attempts to identify the major factors and model these relationships with field data have been limited to specific locations. Using data from 2002-03 to 2004-05 from 34 field experiments at 21 locations in Brazil that represented all major soybean production areas, we attempted to identify weather variables using a 1-month time window following disease detection to develop simple models to predict final disease severity. Four linear models were identified, and these models explained 85 to 93% of variation in disease severity. Temperature variables had lower correlation with disease severity compared with rainfall, and had minimal predictive value for final disease severity. A curvilinear relationship was observed between 1 month of accumulated rainfall and final disease severity, and a quadratic response model using this variable had the lowest prediction error. Linear response models using only rainfall or number of rainy days in the 1-month period tended to overestimate disease for severity <30%. The study highlights the importance of rainfall in influencing soybean rust epidemics in Brazil, as well as its potential use to provide quantitative risk assessments and seasonal forecasts for soybean rust, especially for regions where temperature is not a limiting factor for disease development.

Epidemics of Soybean Rust (Phakopsora pachyrhizi) in Brazil and Paraguay from 2001 to 2003.

In 5 March 2001, a severe rust outbreak was recorded at Pitapó, Paraguay, and the causal organism was determined to be Phakopsora pachyrhizi using polymerase chain reaction (PCR) and DNA sequence analysis. In May, rust surveys showed spread throughout most of Paraguay and into western and northern Parana, Brazil. In the 2001-02 season, rust was widespread in Paraguay, but losses were reduced due to severe drought; however, in Brazil it spread to more than 60% of the soybean acreage, causing field losses estimated at 0.1 million metric tons (MMT). In 2003, the disease was observed in more than 90% of the fields in Brazil, and the projected losses in Mato Grosso and Bahia alone are 2.2 MMT (US$487.3 million). Approximately 80% of the soybean acreage in Brazil was sprayed twice with fungicides at the cost of US$544 million. Differences in efficacy have been observed among the commercial strobilurin and triazol fungicides.

Angular leaf spot of phaseolus beans: relationships between disease, healthy leaf area, and yield.

ABSTRACT Five field experiments were conducted to investigate the relationship between the severity of visible disease (X), area under the disease progress curve (AUDPC), healthy leaf area index on any given day (HLAI), radiation intercepted by healthy leaf area on any given day (HRI), healthy leaf area duration (HAD), total healthy leaf area absorption (HAA), and yield of Phaseolus beans, cultivars Rosinha and Carioca, inoculated with Phaeoisariopsis griseola at several doses. In general, yield was not related to disease severity (X) or AUDPC. In contrast, the highest yields were always related to the highest values of HAD and HAA. The relationship between yield and HAD was linear in each of five trials (29.9 < R(2) < 70.2%, P < 0.001). The relationship between yield and HAA was linear in four of the trials (52.3 < R(2) < 70.3%, P < 0.001) and exponential in one of them (in which the plant canopy was the largest). Singlepoint models using HRI to estimate yield at various times during the crop season were developed. The slope of the yield-HRI relationship proved to be stable (26.8 +/-2.4 g MJ(-1)), regardless of cultivar, locale, planting date, and bean growth stage (from R5 to R8). The yield-HLAI relationship proved to be less consistent. HRI is proposed as a key explanatory variable for a transportable system of disease management; it may be useful in producing precise recommendations at the farm level.

Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP". During a five year period (1988-1993).

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serological assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993, 18 (25.71%) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

[Legionellosis associated with pneumopathies in São Paulo. Study of the etiologic confirmation by isolation and serology]. / Legionelose associada a pneumopatias em São Paulo. Estudo da comprovação etiológica por isolamento e sorologia (1).

The role of Legionella sp as an important pathogen, although reported in many countries, had not been well documented in Brazil. The main objective of the present study is to detect this organism or it's immunological response in patients with pulmonary infections in the city of São Paulo. For this purpose, specific laboratory methodology was introduced to cultivate the agent and demonstrate specific antibodies by serology. Patients from two University centers in São Paulo were studied: 100 from the Hospital Universitario, University of São Paulo with general pulmonary infections and 100 from Hospital das Clínicas, Faculdade de Medicina, University of São Paulo. The latter were selected to exclude pulmonary infections of other bacterial aetiology, and 30 of these were selected from the Renal Transplant Unit. Clinical specimens for cultures included sputum tracheal secretion, pleural, fluid, bronchial washing or lung tissue biopsy. Isolation of Legionella sp was attempted in BCYE medium with and without antibiotics, presumptive diagnosis by biochemical methods and identification through direct immunofluorescence staining and slide agglutination test. Direct evidence of the organism in tissue was attempted by direct immunofluorescence staining. Specific antibodies for Legionella pneumophila serogroup 1 were tested by the indirect immunofluorescence assay. Serology was also carried out in specimens from human contacts with Legionnaires' Disease. Legionella pneumophila serogroup 1 was isolated from two patients, demonstrating the presence of the pathogen in this country. Serology was able to establish present or past infection with the agent in 16 of the 100 patients from Hospital das Clínicas and in only one from Hospital Universitário. In patients considered as high risk groups from Hospital das Clínicas with renal transplantation, serology for present or past Legionellosis was positive in 33% and in 8.5% for community acquired infections. Serology in specimens from Medical personnel in contact with patients of Legionnaires' disease was positive for past infection in one single subject, confirming information already published that direct transmission from person to person is unusual. The introduction of specific methods for laboratorial evidence of Legionella sp infections at the Hospital das Clínicas-Faculdade de Medicina USP community has permitted diagnosis in able time to allow use of specific anti-microbial therapy, with good results.

Comparison of indirect immunofluorescence test for measles antibodies with haemagglutination inhibition and plaque neutralization tests.

Indirect Immunofluorescence (IFA), Plaque Reduction Neutralization (PRN) and Haemagglutination Inhibition (HI) tests for measles antibodies were carried out in 197 sera obtained from umbilical cord and vaccinated children. The IFA was also applied to blood samples collected with filter paper. IFA results demonstrated that the test is relatively simple to perform, with good reproducibility for different antigen lots. Good correlation was obtained between IFA, PRN and HI antibody titers. Better correlation was demonstrated with IFA and PRN than with HI and PRN tests. Sensitivity of IFA in detecting antibody was less effective than PRN, however more effective than HI using rhesus monkey red blood cells. PRN antibody titers over 100 were detected by IFA but not by HI (9.7% with negative results). IFA may be of considerable practical use and able to substitute HI in seroepidemiological surveys and to evaluate vaccine efficacy. It also can be simplified by employing filter paper collected samples.

[Legionella pneumophila associated with acute respiratory insufficiency. 1st isolation in Brazil]. / Legionella pneumophila associada a insuficiência respiratória aguda. Primeiro isolamento no Brasil (1).

Isolation of Legionella pneumophila sero-group 1 with serological evidence of present infection is reported from a 40 year-old male with serious respiratory infection which developed into acute respiratory failure. It was characterized by severe hypoxemia resistant to high inspired oxygen concentrations and radiographically by diffuse infiltrates in both lungs suggesting the clinical aspect of ARDS. Following the introduction of clindamycin, amikacin, ceftriaxone, volume-cycled ventilator and positive end expiratory pressure (PEEP) of 14 cm H2O, stabilization of clinical conditions and gradual recovery were achieved. Suspecting of legionellosis, blood and tracheal secretions specimens were collected for specific laboratory research. From tracheal secretion cultivated in BCYE medium, gran-negative bacilli were isolated and identified as Legionella pneumophila serogroup 1 through cultural and biochemical characteristics and direct immunofluorescence and slide agglutination tests. Serology (IFA) with blood samples collecting during the 1st, 3rd, 4th and 6th weeks of illness demonstrated antibody titers to the isolated microorganism of 128, 1024, 4096 and 8192, respectively. Definitive results were obtained during the patient's recovery. The authors emphasize: a) the demonstration of the presence of Legionella sp. as a pathogenic agent in Brazil; b) the importance of supportive care in the clinical outcome; c) the need of remembering this pathogen while making differential diagnosis of pneumonias and of continuing to pursue this etiology with specific laboratory methodology.

[In vitro susceptibility to a new antimicrobial agent (imipenem) of pathogens isolated from inpatients at various centers]. / Estudo da suscetibilidade "in vitro" a um novo antimicrobiano (imipenem) de patógenos isolados de pacientes hospitalares em vários centros.

Imipenem is a beta lactam antibiotic, a highly potent new carbapenem with broad antibacterial spectrum. To test the "in vitro" efficacy of this antimicrobial agent in pathogens more frequent in several Medical Centers in Brazil, susceptibility testing with 10 mcg imipenem disks and, or corresponding MIC were carried out with 1231 recent isolates of 41 different bacterial species, obtained mainly from hospitalized patients in 5 different medical centers of the cities of S. Paulo, Rio de Janeiro and Salvador. Our preliminary results with this antibiotic, in final phases of clinical and laboratorial experimentation in this country, are very promissing with, 96.79% of susceptibility of test isolates to 10 mcg imipenem disks and corresponding MIC correlation of up to 4 micrograms/ml. (92.31%). Of the 9 bacterial species more frequently isolated totaling 1108 (82%) of the 1230 test isolates, disk susceptibility was 99% (E. coli), 93% (Pseudomonas aeruginosas), 87% (Staphylococcus aureus), 100% (Klebsiella pneumoniae), 98% (Klebsiella sp), 97% (Proteus mirabiles), 94% (Enterobacter sp), 100% (Streptococcus faecalis) with good MIC correlation (up to 8 mcg/ml) and 100% for the anaerobic species Bacteroides sp (MIC up to 4 micrograms/ml). "In vitro" efficacy to hospital pathogens with high frequency of resistance to most antibiotics as Pseudomonas aeruginosa and to anaerobes notably Bacteroides sp is emphasized.

Cytomegalovirus mononucleosis in children and adults: differences in clinical presentation.

In 2 previously healthy groups of 14 children and 17 adults with cytomegalovirus mononucleosis, significant clinical differences were observed. Cervical lymphadenopathy, hepatomegaly and lymphocytosis (greater than 5000/microliter) were more common in children and protracted fever more common in adults. Exudative tonsillitis indistinguishable from infectious mononucleosis was sometimes seen in children but never in adults.

Aneurisma da arteria esplenica. / Aneurysm of splenic artery

Apresentam os autores a experiencia de dois casos de aneurismas de arteria esplenica agudos no servico de cirurgia do HECC. Fazem revisao da literatura enfatizando o exame fisico e radiologico simples do abdomen dados fundamentais para o diagnostico em que o sinal do "anel de sinete" devera ser sempre pesquisado. Referem ainda os magnificos resultados obtidos com a aneurismectomia e esplenectomia

Cefoxitin penetration into cerebrospinal fluid in patients with purulent meningitis.

The penetration of cefoxitin into cerebrospinal fluid (CSF) was studied in 25 patients with purulent meningitis treated with antibiotics other than cefoxitin. Each patient received three 2-g doses of cefoxitin at 6-h intervals. Blood and CSF samples were obtained before and at 2, 4, or 6 h after the first and third doses. CSF cefoxitin concentrations were found in all patients and varied between 1.2 and 22.0 microgram/ml, with a majority of the concentrations falling within a range from 1.2 to 6.2 microgram/ml. The concentrations tended to be higher in CSF samples drawn after the third cefoxitin dose than in those drawn after the first cefoxitin dose, indicating an accumulation of cefoxitin in CSF with repeated doses. Peak cefoxitin concentrations in CSF seemed to occur between 2 and 6 h after intravenous administration of the drug since the highest concentrations were found in patients from whom CSF samples were taken 4 h after the doses. In patients with bacterial meningitis, it should be possible to achieve therapeutic cefoxitin levels in CSF by using nontoxic doses of the antibiotic.