Expressed sequence tags from the phytopathogenic fungus Botrytis cinerea

A large set of genes was identified in the phytopathogenic fungus Botrytis cinerea by using an expressed sequence tag approach. The fungus was grown in axenic culture and a cDNA library was produced. From this library, 6559 ESTs were obtained. The combined sequences represent 3026 unisequences that corresponds to approximately one-quarter of the estimated total number of genes in B. cinerea. Approximately 18% of the ESTs showed significant similarities with genes coding for proteins with known functions,~56% were similar to genes coding for proteins with unknown functions and ~26% were orphans. A substantial B. cinerea gene inventory including putative virulence factors was therefore obtained and is now available at the Génoplante-Info Database interface (http://urgi.infobiogen.fr///Projects/GPiDB/Interface/).     

The effect of short-term socio-economic and demographic change on landuse dynamics and its corresponding geomorphic response with relation to water erosion in a tropical mountainous catchment,Ecuador

The analysis of aerial photographs over a 33-year period (1962–1995) shows that land use in the study catchment is highly dynamic as a response to the land reform programs of the 1960s and 1970s and a strong population increase. The secondary forest is increasingly replaced by grassland while old grasslands are now used as cultivated land. Despite the increased pressure on the land, the upward movement of agricultural activity and the concurrent deforestation, the overall forest cover did not decline. The deforestation in the uplands is compensated for by a regeneration of secondary forest on abandoned rangelands and afforestation with Eucalyptus trees in the low-lying areas. The land use changes resulted in a strong decrease of the areas subject to intense soil degradation: afforestation with Eucalyptus trees on degraded lands was successful in controlling soil erosion in the lower parts of the catchment. The relationship between land use and sediment load in the river system is not straightforward. Statistical analysis of a time series of suspended sediment concentrations, which were measured at the outlet of three distinctive sub-catchments for a six-year period (1994 – 2000), revealed that the geomorphic response of the river system is not only dependent on the land use and the area affected by water erosion, but also on the spatial connectivity between sediment producing areas and the river network.This revised version was published online in May 2005 with corrections to the Cover Date.     

Effect of oral administration of L-lysine on conjunctivitis caused by feline herpesvirus in cats

OBJECTIVE: To determine whether oral administration of L-lysine to cats would lessen the severity of conjunctivitis caused by feline herpesvirus (FHV-1). ANIMALS: 8 healthy young adult cats. PROCEDURE: Cats received oral administration of lysine monohydrochloride (500 mg, q 12 h) or placebo (lactose) beginning 6 hours prior to inoculation of virus. The left conjunctival sac received a 50-microl suspension of FHV-1 grown in cell culture (1.8 X 10(8) tissue culture infective dose50) on day 1. Cats were evaluated and scores given for clinical signs each day for 21 days. Samples for virus isolation were collected from the eye and throat every third day. Plasma lysine and arginine concentrations were measured prior to the study and on days 3, 14, and 22. RESULTS: Cats that received lysine had less severe conjunctivitis than cats that received placebo. Virus isolation results did not differ between the groups. Plasma lysine concentration was significantly higher in cats that received lysine, compared with control cats, whereas plasma arginine concentrations did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of 500 mg of lysine to cats was well tolerated and resulted in less severe manifestations of conjunctivitis caused by FHV-1, compared with cats that received placebo. Oral administration of lysine may be helpful in early treatment for FHV-1 infection by lessening the severity of disease.     

Characteristics of Salmonella enteritidis contamination in eggs after oral,aerosol, and intravenous inoculation of laying hens

Experimental infection models are useful tools for understanding how Salmonella enteritidis is deposited in eggs and for testing potential strategies to control eggborne transmission of disease to humans. Oral inoculation of laying hens is presumed to provide the closest simulation of naturally occurring infections, but alternatives such as intravenous or aerosol inoculation have sometimes been recommended as options to induce higher incidences of egg contamination. The present study compared the frequency, level, and location of S. enteritidis deposition in egg contents after experimental inoculation by three different routes. In two replicate trials, specific-pathogen-free laying hens were infected with an S. enteritidis culture mixture prepared to optimize invasive behavior. Groups of hens received either an oral dose of 10(9) S. enteritidis, an aerosol dose of 10(9) S. enteritidis, or an intravenous dose of 10(5)-10(7) S. enteritidis. Oral inoculation led to the highest incidence of fecal shedding of S. enteritidis, whereas intravenous inoculation produced the highest specific antibody titers. Eggs laid during the first 21 days postinoculation were cultured to detect and enumerate S. enteritidis in the yolk and albumen. No significant differences were observed among the three inoculation routes in the frequencies of isolation of S. enteritidis from either yolk or albumen. For all three routes of administration, S. enteritidis was recovered more often from yolk (at frequencies ranging from 4% to 7%) than from albumen (0 to 2%). Over 73% of contaminated eggs harbored fewer than 1 colony-forming unit (CFU) of S. enteritidis per milliliter, and only 3% of such eggs contained more than 100 CFUs/ml. Significantly higher levels of S. enteritidis contaminants were associated with intravenous inoculation than with the other routes. No advantage of using aerosol or intravenous administration of S. enteritidis as an alternative to oral inoculation for inducing the production of contaminated eggs was evident in this study.     

Comparison of two formaldehyde administration methods of in ovo-injected eggs

Formaldehyde administration in the hatchery can be very useful in decreasing microbial numbers. However, its use is controversial because of the adverse effects that can occur to chicks and people. This study was designed to look at alternative methods of application of formaldehyde in the hatchery. In addition, the study compared the effects of these methods of application on in ovo-and non-in ovo-injected eggs. All in ovo-injected eggs were given diluent only with no vaccine or antibiotic added. In hatchers containing both in ovo-injected eggs and non-in ovo-injected eggs, formaldehyde was administered two ways, dose (DOSE) and constant rate infusion (CRI). In the DOSE hatcher, 12 ml of formaldehyde was administered at one time every 12 hr, whereas in the CRI hatcher, the same volume was administered at a rate of 1 ml/hr over a 12-hr period. A control (CONT) hatcher received 12 ml of distilled water at the same time that the DOSE hatcher was given formaldehyde. In the DOSE hatcher, a peak concentration of formaldehyde of 102 ppm was reached. The CRI was maintained at approximately 20 ppm of formaldehyde. At pipping, the aerosol bacterial load in the hatchers receiving formaldehyde (DOSE, 130 colony-forming units [CFU]/m3; CRI, 82.5 CFU/m3) was significantly less than in the CONT hatcher (235 CFU/m3). At hatch, the CRI (337.5 CFU/m3) was not able to control bacterial levels and only the DOSE hatcher (150 CFU/m3) had a significantly lower aerosol bacterial count. The CRI non-in ovo-injected eggs (93.39%) had a significantly higher percentage of hatch of fertile compared with non-in ovo-injected eggs exposed to water (84.27%). In ovo-injected eggs in CONT and DOSE treatment groups contained significantly higher percentages of visual contamination than non-in on-injected eggs in the same hatchers. This difference had numerical significance only in the treatment groups within the CRI hatcher. The chicks were then placed into replicate treatment groups and grown for 14 days. Chicks from the CRI in ovo-injected eggs had a statistically significant improvement in feed conversion ratio (1.24) at 14 days when compared with chicks from CONT non-in ovo-injected eggs (1.29). All formaldehyde-exposed chicks had numerically lower feed conversion ratios compared with the CONT exposed chicks.     

History of the control of foot and mouth disease

From the many existing documents on the history of foot and mouth disease, it is possible to describe the practical measures adopted for disease surveillance and control from ancient times until the 20th century.

Surveillance was based on diagnosis or post-mortem examination, and also on knowledge of the conditions under which infection occurred: aetiology, pathogenesis, mode of infection, susceptible species, virulent material, etc. The historical facts are assembled and compared, with comments on each of these points.

Control was based upon the application of isolation, then slaughter or aphtisation, then vaccination. A study of these various procedures makes it possible to compare their efficacy.

Résumé

D'après les nombreux documents existant sur l'histoire de la fièvre aphteuse il est possible de décrire les mesures adoptées pour suivre l'évolution de la maladie et la maîtriser, depuis l'Antiquité jusqu'au XXème siècle.

La surveillance de la maladie était fondée sur le diagnostic clinique ou l'examen des lésions, mais aussi sur la connaissance des condition de l'infection: étiologie, pathogénie, mode de transmission du contage, matières virulentes, etc. Les faits historiques concernant ces différents points sont rassemblés, comparés et commentés.

La maîtrise de la fièvre aphteuse a été assurée soit par des mesures d'isolement, puis d'abattage sanitaire, soit par des opérations d'aphtisation puis de vaccination. L'étude de ces différentes stratégies permet de comparer leur efficacité respective.