Overcoming environmental deterioration through defensive expenditures: field evidence from Bahía del Tóbari (Sonora, México) and implications for coastal impact assessment.

The costs of the maneuvers that fishermen and shrimp farmers have to undertake in a coastal scenario where both the access to navigable waters and water quality have decreased were interpreted as defensive expenditures. Maneuvers were prompted by profound changes in water circulation and siltation mode imposed by major shifts in regional and local land-use patterns. In coastal scenarios under heavy land-based discharges and local geomorphic modifications, local users with little chance to move away may modify their routines in order to maintain existing levels of utility. The concept of defensive expenditures could be used to assess social responses to adverse changes in environmental and resource conditions, as a means to distinguish stages in which local sectors respond individually from qualitatively different stages in which intersectoral events are more conspicuous.

Factors promoting colonization by legionellae in residential water distribution systems: an environmental case-control survey.

As part of a case-control study of community-acquired Legionnaires' disease, several factors related to residential water distribution systems and public drinking water systems were studied in the homes of 124 patients with community-acquired Legionnaire's disease and in the homes of 354 controls. The presence of water reservoirs and hot water tanks was studied in residential systems. Factors such as deficient chlorine levels, pipe repairs and other work, water flow interruptions, the use of alternative water sources, inadequate cleaning operations in public water reservoirs, and the position of the home within the public network (and whether this location constituted an endpoint) were studied in public water supply systems. Levels of legionellae in domestic water samples were also measured. Although the use of water reservoirs and hot water tanks promotes colonization by legionellae in residential systems, none of the variables studied seems to increase the incidence of community-acquired Legionnaires' disease.

[Community-acquired legionellosis in the Barcelona region between 1992 and 1999: epidemiological characteristics and diagnostic methods]. / Legionelosis comunitaria en las comarcas de Barcelona entre 1992 y 1999: características epidemiológicas y métodos diagnósticos.

BACKGROUND: The epidemiological characteristics of community-acquired legionellosis are not well known. We present here legionellosis cases appearing in Barcelona, Spain, districts during 1992-1999. PATIENTS AND METHOD: Questionnaire on socio-demographic, epidemiological, clinical and diagnostic data. 285 community-acquired cases of legionellosis were notified (67% of total). Incidence values increased from 0.03/100,000 in 1992 to 3.14 in 1999. Mostly used diagnostic method since 1996 was the urinary antigen test. CONCLUSIONS: The incidence of legionellosis increased sharply during the studied period. We believe that use of urinary antigen-based diagnosis allows for a better knowledge of community-acquired legionellosis.