Legionnaires' Disease

authorities in Christchurch are dismissing the coincidence of 2
outbreaks of legionnaires' disease in the city in 2005. An elderly
man has died and 3 others have contracted the disease from potting
mix and compost bags.  This latest occurrence is not connected to the
outbreak earlier in 2005 which left 3 people dead and was linked to
cooling towers.

Second legionnaires' outbreak
27/10/2005 5:15:03

Health authorities in Christchurch are dismissing the coincidence of
two outbreaks of legionnaires' disease in the city this year.

An elderly man has died and three others have contracted the disease
from potting mix and compost bags.

This latest occurence is not connected to the outbreak earlier this
year which left three people dead and was linked to cooling towers.

Medical Officer of Health Dr Alistair Humphrey does not consider the
two outbreaks strange. He says the first outbreak was unusual, but
cases linked to potting mix are nothing new and people often die from

Dr Humphrey says gardeners need to take extra care when opening
potting mixes or compost bags.


Potting soil/sludge
"One word of caution with any compost that has sewage sludge as an ingredient, as you say
Compro has: in California, many counties have banned such products from farmlands because of
environmental or health concerns. The farming industry worries that sludge may boost heavy metal
content in the soil."

History of Compost Research for Potting Media
Throughout the 1960s, the nursery industry explored the use of tree barks as peat substitutes in
container media to reduce production costs. From these studies, composting technologies for tree
bark developed. During the 1980s, similar processes were developed for food and agricultural
wastes and municipal sludge.


Some bagged composts have additives have like food waste, cocoa shells, coffee residue and coir
as well as the usual wood chips, bark mulch and peat. Others (Bay State Organics from
Massachusetts and Milorganite from Milwaukee) are made from sewerage sludge. These are fine
for trees and flowers, but they are not recommended for all vegetables because of occasional high
heavy metals.
pathogen regrowth in compost :

There is lots of documentation of pathogen regrowth (see BioCycle June 1995,
June 1996, and June 1996 for some excellent discussions). Most of this work
was conducted with biosolids, but work I have done here in California shows
that regrowth is possible post-pfrp even in yard waste only composts. Some
have argued that the PFRP temperatures (designed to kill human pathogens in
sludge) tend to kill off all beneficial bacteria allowing for potential
regrowth of which ever species gets there first, or thrives best.

Could human pathogens be reintroduced into the unstable compost via
> the vehicle transporting the unstable compost to the compost site, human
> contact, via flies, rats, seagulls at the compost site?

Yes. One of the findings of some early research was that a really good way
to re-grow pathogens was to introduce "fresh" material to composted sludge.
I also believe that a relatively "sterilized" medium (post PFRP compost) is
ripe for re-introduction of pathogens. The real question is whether or not
high e. coli numbers which you may find (and we have found in post PFRP
compost) truly indicate a problem with "human pathogens" and/or if this is a
water quality threat. Unfortunately though moist composters in CA test their
stormwater, I don't know of any who are required to test for potential
pathogens there.

Matthew Cotton
Integrated Waste Management Consulting


Legionnaires Disease
An outbreak of a fulminant pneumonia occurred in 1976 with persons attending a state American
Legion convention in Philadelphia, PA USA. The causative agent was identified as a bacterium,
Legionella pneumophila. Outbreaks have been linked to cooling towers, evaporative towers, air-
conditioning units, hot-tubs, charcoal filtered water, and dust at construction sites. Most recently, a
case was linked to septic waste contaminated compost. The treatment of choice has been
erythromycin. Since this is an air born infection, smokers and immunosuppressed patients are the
most susceptible population.


US EPA:       http://www.epa.gov/ORD/NRMRL/Pubs/600r03111/600r03111chap2.pdf
page 2-5 (5 of 25) "Palmer et al (1993) found PCR to be sensitive and specific for Legionalla in
sewage treatment plant influent and in ocean receiving waters."


Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids)
David L Lewis,1,2 David K Gattie,3 Marc E Novak,2 Susan Sanchez,4 and Charles Pumphrey5

Retrospective studies have been done on workers exposed to sewage sludges who have reported
illnesses. Gregersen et al [5], for example, investigated five workers who experienced fever and flu-
like symptoms after repairing a decanter used for concentrating sludge at a sewage treatment
plant. High concentrations of Legionella pneumophila (serogroup 1) found in the sludge along with
positive antibody titers in all five workers indicated that they developed Pontiac fever from contact
with sludge. Similarly, NIOSH investigated five workers complaining of headaches, stomach cramps,
and diarrhoea at a sludge processing operation [6]. Investigators isolated a variety of enteric,
opportunistic pathogens from bulk sludge samples and airborne particulates, including species of
the genera Mycobacterium, Pseudomonas, and Staphylococcus. Based on the nature and timing
of their symptoms, investigators concluded that ingestion or inhalation of pathogens in sewage
sludge probably caused the illnesses.


DR. EDO MCGOWAN, California

There is increasing interest in the potential role of free-living
amoebae as reservoirs and vectors of pathogenic bacteria. The best known of such pathogenic
bacteria is Legionella, and several studies provide evidence for the importance of
the amoeba-bacterium relationship in the biology and epidemiology of
pneumonia caused by this pathogen. Further, Legionella by itself is about 420 times more
tolerant of chlorine than E.coli [Australian Government study—Health Risks Due to
Microbial Pathogens in Wastewater. See also Boyden, 1993].

Additionally, as a pathogen arising from moist areas and cooling water
systems, it may be purged into sewers in large amounts from hospitals.
Legionella-contaminated hot water systems and moist sanitary areas in six hospitals were sampled
for amoebae by following a standardized collection protocol. The temperature
tolerance of amoebae from hot water systems was strikingly different from that of
amoebae from moist areas. At 44 degrees C on agar, 59% of amoebic isolates
sampled from hot water systems showed growth. The corresponding value for isolates
from moist areas was only 17%. Six Acanthamoeba isolates from the moist areas were
considered potential pathogens. Four Hartmannella and two Saccamoeba
isolates from hot water could be cultured at 53 degrees C. [Appl Environ
Microbiol. 1998 May;64(5):1822-4. ] NOTE THE TEMPERATURE HERE==127 degreed F is
considerably higher that typical sludge cooking temps of 98 degrees F
used in 'wastewater treatment plants.

Legionella sparks compost warning - 27 Oct 2005 - Health & Fitness
Health and Fitness - News and opinion from The New Zealand Herald.
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