Issue: 10/02

Editor's Note: We received the following report on legionella from France, indicating the steps that are being taken in Europe to combat the growth of the bacteria.

Legionnaires' Disease has been considered a catastrophic disease that must be reported to the medical authorities in France since 1987. During the last decade, public health monitoring systems for it have been strengthened. Today, this new health hazard that arises from buildings has become an emerging public health problem in industrialized countries. The resulting respiratory infections are behind the recurrent epidemics emanating from hot water systems in buildings.

Sensitive populations, mainly the elderly or people with immune deficiencies, are at risk from this respiratory disease, particularly in public buildings such as healthcare establishments (hospitals, clinics, thermal baths), hotels, campsites, swimming pools and gymnasiums. "Infection arises from inhalation of a large dose of micro-droplets carrying pathogenic bacteria by these receptive people," explain French experts from France's Public Health Council, the authors of a recent report on the management of legionella hazards.

The cause of this new bacteriological hazard is bacilli naturally occurring in water supplies that have a particular affinity for hot water in the range from 77 to 104 degrees F. These tend to multiply within biofilms in pipework. Contamination of the lungs occurs only with the inhalation of an aerosol that can come from showers, lengthy baths, and outlets for air cooling towers. Two processes exist for eradicating legionella from contaminated water systems: thermal shock and chemical disinfection (chlorination).

As the optimal temperature conditions for the growth of legionella are between 86 and 113 degrees F, raising the temperature of the water to 158 degrees F for one minute in the water system will destroy the legionella. The French company PM Industrie, located in southwestern France's Gironde region, is developing a process patented in August 2000 by the firm Jean-Jacques Boiffier which provides cyclic and continuous pasteurization of domestic hot water.

The second method of treating water systems uses shock chlorination (57 to 76 mg/gallon of chlorine added over 24 hours). However, this type of decontamination strongly corrodes pipework, damages joints, and gives the water a strong smell of chlorine. It also requires draining the installations. French company Thetis Environnement has developed a technology in collaboration with the EDF Research Center and with the support of ANVAR [1][1] that generates chlorine dioxide using electrolysis, thereby avoiding the storage of reagents and corrosion of the installations.

In another effort to combat the bacteria, the Water and Healthcare Equipment Service of France's Building Science and Technology Center (CSTB) has been awarding certification for products and service providers that address the disinfection of water systems (systems for domestic hot water, heating, air-conditioning, and air-cooling towers. The certification testifies to both the company's quality assurance system and to the procedure for carrying out the disinfection process.

In a related note, a "Legionella Prevention Training Course" will be offered December 5-6, 2002, in the Washington, DC, area by HC Information Resources Inc. and the Virginia Department of Mental Health. The course will be held at VDMH's Northern Virginia Training Center in Fairfax, VA, approximately 10 miles from Washington Dulles International Airport.

Matt Freije, author of Legionellae Control in Health Care Facilities: A Guide for Minimizing Risk, will be the instructor. Freije will give an overview of risk reduction strategies and then provide detailed recommendations for plumbing systems, cooling towers and other aerosolizing devices. Environmental sampling methodology will be outlined, including interpretation of results. Risk assessment checklists, domestic water disinfection methods, and outbreak investigation procedures will also be covered. Graduates of past seminars have especially liked the case studies that allow students to apply the principles to real situations.

The tuition is $495, or $425 for three or more, which includes a copy of Legionellae Control in Health Care Facilities: A Guide for Minimizing Risk, a course manual, certificate, and 1.2 CEUs.

Only 30 seats are available, so early registration is encouraged. To register or get more information, visit, telephone 1-800-801-8050, or e-mail