Dr. Edo McGowan
Subject: RE: Midwest Town Sees Return of Old Disease
Date: 11/23/2006
Would be interesting to see if this is also transmitted in aerosols from wastewater treatment plants---I suspect that it can
be so transmitted. Although it may be more fragile than some pathogens, it can contaminate surfaces. Gerba and Rusin
looked at positive finger to mouth disease transmission from common household objects. Thus those in the immediate
down-wind of a sewer plant may be at increased risk as are the plant's employees. Thus there then can follow person to
person spread as people move about the community during the early phases of an epidemic. As the rate of infection
goes up, the levels of pathogens will also increase in the sewage. The role of sewer plants, although this has not been
extensively studied, may be important in the augmentation of disease states within the community. It would be well to
considered this avenue in airborne spread of disease. For those pathogens that can survive long periods, this may
confound epidemilogic analyses. If some of you know those involved in this outbreak, the following might be forwarded to
them.
Cheers----------------Edo
How long do nosocomial pathogens persist on inanimate surfaces? A systematic review.
Kramer A,
Schwebke I,
Kampf G.
Institut fur Hygiene und Umweltmedizin, Ernst-Moritz-Arndt Universitat, Greifswald, Germany. kramer@uni-greifswald.de
BACKGROUND: Inanimate surfaces have often been described as the source for outbreaks of nosocomial infections.
The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces.
METHODS: The literature was systematically reviewed in MedLine without language restrictions. In addition, cited
articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental
evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included. RESULTS:
Most gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or
Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp.,
Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for
months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae,
however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria,
including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important
nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis
glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the
respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days.
Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months.
Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV
type 1 and 2, have been shown to persist from only a few hours up to 7 days. CONCLUSION: The most common
nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of
transmission if no regular preventive surface disinfection is performed.
By definition, an aerosol is able to remain in suspension for prolonged periods because of its low settling velocity. For
spherical particles of unit density the settling time for a 3-M fall is noted in the table below. From this, considering the
size of both bacteria and viruses, it will be noted that aerosol movement is potentially considerable.
TABLE
Assumptions: 5 mpg average wind speed, laminar flow. The assumptions would be upset within an urban setting with
buildings, up-currents, and turbulence from traffic. Adapted from Tellier.
Particle Diameter………………..Settling Time………..Distance at wind speed 5 mph
100 uM……………………………….10 sec…………………..44 ft
20 uM…………………………………4 minutes……………….1780 feet
10 uM………………………………….17 minutes……………..7480 feet (1.4 miles)
5 uM……………………………………62 minutes……………approx 5 miles
< 3uM………………………………….These essentially will not settle.
The median diameters at which particles exhibit aerosol behavior also corresponds to the size range that will reach the
deepest recesses of the respiratory tract.
While keeping in mind the material below in the abstracts discussing drift from sewer plants and then the idea of drift
distance for a bacterium or smaller particle, the issue of sewer plant aerosol generation is worrisome. Since sewer works
also provide the opportunity for numerous organisms to be brought into close proximity with each-other, there is ample
and well documented opportunity for genetic exchange. Thus sewer plants, as currently designed and operated, are
generators of disease and not, as myth would lead one to believe, providing treatment that reduces disease.
Review of Aerosol Transmission of Influenza A Virus
Raymond Tellier*† commentcomment
*Hospital for Sick Children, Toronto, Ontario, Canada; and †University of Toronto, Toronto, Ontario, Canada
Suggested citation for this article
Abstract
In theory, influenza viruses can be transmitted through aerosols, large droplets, or direct contact with secretions (or
fomites). These 3 modes are not mutually exclusive. Published findings that support the occurrence of aerosol
transmission were reviewed to assess the importance of this mode of transmission. Published evidence indicates that
aerosol transmission of influenza can be an important mode of transmission, which has obvious implications for
pandemic influenza planning and in particular for recommendations about the use of N95 respirators as part of personal
protective equipment.
++++++++++++++++++++++++
Comparative investigation of airborne culturable microorganisms in sewage treatment plants.
Haas DU,
Reinthaler FF,
Wust G,
Posch J,
Ruckenbauer G,
Marth E.
The present study investigated emissions and emmissions of airborne microorganisms (mesophilic bacteria, Escherichia
coli, molds, Aspergillus fumigatus, thermophilic actinomycetes/bacilli) in sewage treatment plants. For the aerobiological
investigations three sewage treatment facilities with an activated-sludge process, capacities between 2000 and 28,000
PE and different cleaning steps were selected. The measurements of microorganism emission were conducted in the
area of the intake (screen), in the area of biological treatment (activated sludge tank) and at a distance of 10 m from the
activated sludge tanks. In order to determine the emmission, additional measurements were conducted leeward of the
plant at a distance of 200 m. Samples were taken using four parallel six-stage Andersen 1 AFCM volumetric samplers. In
the area of the intake counts for bacteria were 7.4 x 10(2) CFU/m3 (median), for thermophilic actinomycetes 1.8 x 10(1)
CFU/m3, for thermophilic bacilli 7.1 x 10(1) CFU/m3, for molds 2.4 x 10(3) CFU/m3 and for Aspergillus fumigatus 1.8 x 10
(1) CFU/m3. Only isolated airborne coliform recoveries, i.e. E. coli, were detected. In the area of the activated sludge
tank, in the adjoining area (10 m) and in the vicinity of the plants (200 m), the counts for all microorganism groups
investigated corresponded to natural conditions. The results show that the counts of culturable aerogenic
microorganisms in and in the immediate surrounding of the sewage plants investigated are low. Although the possibility
of an infection through inhalation cannot be ruled out, the direct contact with sewage is much more critical.
PMID: 12096685 [PubMed - indexed for MEDLINE]
Note, 200 m is about 2 1/2 city blocks.
Comparison of coliphage and bacterial aerosols at a wastewater spray irrigation site.
Bausum HT,
Schaub SA,
Kenyon KF,
Small MJ.
Microbiological aerosols were measured on a spray irrigation site at Fort Huachuca, Ariz. Indigenous bacteria and tracer
bacteriophage were sampled from sprays of chlorinated and unchlorinated secondary-treatment wastewaters during day
and night periods. Aerosol dispersal and downwind migration were determined. Bacterial and coliphage f2 aerosols were
sampled by using Andersen viable type stacked-sieve and high-volume electrostatic precipitator samplers. Bacterial
standard plate counts averaged 2.4 x 10(5) colony-forming units per ml in unchlorinated effluents. Bacterial aerosols
reached 500 bacteria per m3 at 152 m downwind and 10,500 bacteria per m3 at 46m. Seeded coliphage f2 averaged
4.0 x 10(5) plaque-forming units per ml in the effluent and were detected 563 m downwind. Downwind microbial aerosol
levels were somewhat enhanced by nighttime conditions. The median aerodynamic particle size of the microbial aerosols
was approximately 5.0 micrometer. Chlorination reduced wastewater bacterial levels 99.97% and reduced aerosol
concentrations to near background levels; coliphage f2 was reduced only 95.4% in the chlorinated effluent and was
readily measured 137 m downwind. Microbiological source strength an meteorological data were used in conjunction
with a dispersion model to generate mathematical predictions of aerosol strength at various sampler locations. The
mean calculated survival of aerosolized bacteria (standard plate count) in the range 46 to 76 m downwind was 5.2%,
and that of coliphage f2 was 4.3 %.
PMID: 7055376 [PubMed - indexed for MEDLINE
Emission of microorganisms from sewage treatment plants depending upon construction differences of single structural
parts]
Eikmann T,
Schroder S,
Pieler J,
Bahr H,
Einbrodt HJ.
In order to examine the influence exerted by the differing design of individual water treatment plant units on the emission
rate of micro-organisms and the associated degree of exposure to which plant personnel is subjected, measurements
were taken at three different types of treatment plants. Measurements were made using "Biotest" RCS Air Samplers.
The total count of colonies was determined by means of Agar Strips GK-A (tryptic soy agar). Enterobacteriaceae were
quantitatively ascertained using Agar Strips C (MacConkey agar), particular attention being paid to the determination of
the coliform bacteria as faeces indicators. Agar Strips S (mannitol salt agar) were used to measure the count of
staphylococci using Agar Strips HS (rosa Bengal streptomycin agar). Before taking measurements, the prevailing
climatic conditions were recorded. It could be ascertained that the enclosure of the inflow area (screw conveyor pump
station and aerated grit removal tank) lead to a considerable increase in the concentration of microorganisms in the air
within the housing. The values dropped however, when adequate ventilation was provided. Differing oxygen in the
activated sludge tanks - finebubble aeration at the tank bottom or the blowing in of air via centrifugal blowers - lead to
large variations in the emission rates. However, the less the waste water is agitated, the lower the emission rates. In the
case of fine-bubble aeration, rates which are also normally to be found in the "non-burdened" outside air were even
recorded close to the aeration tank. In cases of centrifugal blower, the aeration tank should be covered with a shield.
With this type of aeration the waste water is emitted radially towards the walls of the tank. The use of a sprinkler unit on
an aeration tank equipped with centrifugal blower - to avoid foam formation on the surface of the water - does not lead
to an increase in the already high emission rate. An increase in air pollution through mould fungi from waste water
treatment plants could not be found. In conclusion, it can be said that different individual plant unit designs have a large
influence on the concentration of micro-organisms in the ambient air of places of work of waste water treatment plant
personnel. Emission rates can be limited to such a degree that, even in the immediate vicinity of the plant units, a
decrease of micro-organism concentrations can be attained as comparable to the area outside the treatment plant.
Evaluation of the environmental impact of microbial aerosols generated by wastewater treatment plants utilizing different
aeration systems.
Brandi G,
Sisti M,
Amagliani G.
Using three sampler devices (SAS, Andersen Six-Stages and All Glass Impinger), the environmental impact of bacterial
and fungal aerosols generated by municipal wastewater treatment plants operating with different methods of sludge
oxygenation were evaluated. The highest microbial concentrations were recovered above the tanks (2247 cfu m-3) and
in downwind positions (1425 cfu m-3), where a linear correlation (P < 0.05) was found between the quantity of sewage
treated and the entities of microbial aerosol dispersion. Moreover, an exponential increase (P < 0.05) in the bacteria
recovered from the air occurred at increasing times of treatment. However, after long-term plant operation, high
bacterial and fungal concentrations were found in almost all of the sites around the plant. Coliforms, enterococci,
Escherichia coli and staphylococci were almost always recovered in downwind positions. Considerable fractions (20-
40%) of sampled bacteria were able to penetrate the final stages of the Andersen apparatus and thus, are likely to be
able to penetrate the lungs. The plant operating with a fine bubble diffused air system instead was found to generate
rather low concentrations of bacteria and fungi; moreover, staphylococci and indicator micro-organisms were almost
absent. Finally, salmonellae, Shigella, Pseudomonas aeruginosa and Aeromonas spp. were not detected in either of the
plants. The results indicate a remarkable dispersion of airborne bacteria and fungi from tanks in which oxygen is
supplied via a mechanical agitation of sludge, and suggest the need to convert them to diffused aeration systems which
pose a lesser hazard for human health.
PMID: 10792545 [PubMed - indexed for MEDLINE]
Site-related airborne biological hazard and seasonal variations in two wastewater treatment plants.
Fracchia L,
Pietronave S,
Rinaldi M,
Giovanna Martinotti M.
Results of a study conducted to assess the degree of airborne bacterial contamination generated by two wastewater
treatment plants (WWTP) with different treatment systems and evaluate the dispersion of potential pathogens, have
been described. Aerosols samples were collected in summer and winter with an agar impact sampler from several plant
sites. External upwind and downwind controls were also examined. Total colony-forming counts of mesophilic and
thermophilic bacteria, actinomycetes and streptomycetes, Gram-negatives, coliforms and sulfite-reducers were
determined. Selective media were used in order to detect pathogenic bacteria. The lowest concentrations of mesophilic
and thermophilic bacteria were 8 and 28 CFU/m(3) in plants A and B respectively, the highest >40,000 CFU/m(3) in both
plants. Strains of Escherichia coli, Clostridium perfringens, Staphylococcus aureus and Enterococcus spp. were isolated
in some sites of the two plants. Salmonella spp., Yersinia enterocolitica and Legionella spp. were never detected. The
activities involving nebulization and mechanical aeration of wastewaters and the sewage inflows have proved to be of
greatest potential risk. In both plants, we found a statistically significant dependence of bacterial contamination on the
season for many of the analyzed parameters but a clear seasonal trend could not be observed.
PMID: 16678881 [PubMed - indexed for MEDLINE]
Related Links
[Exposure assessment to harmful agents in workplaces in sewage plant workers] [Med Pr. 2005] PMID: 16218135
Assessment of bioaerosols and inhalable dust exposure in Swiss sawmills. [Ann Occup Hyg. 2005] PMID: 15699057
Exposure to bioaerosols in a municipal sewage treatment plant. [Ann Agric Environ Med. 2003] PMID: 14677919
Bioaerosol sampling by a personal rotating cup sampler CIP 10-M. [J Environ Monit. 2006] PMID: 16395458
Workers' exposure to airborne bacteria and endotoxins at industrial wastewater treatment plants. [Am Ind Hyg Assoc J.
1994] PMID: 7992797
See all Related Articles...
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From: BynJam@aol.com
To: FPecar4525@aol.com, edo_mcgowan@hotmail.com, hshields@worldpath.net, cgsnyder@post.harvard.edu
Subject: Midwest Town Sees Return of Old Disease
Date: Thu, 23 Nov 2006 14:48:10 EST
Another hidden epidemic emerges.
Jim
Updated: 07:35 PM EST
IM This E-mail This
By Deborah Cohen, Reuters
CHICAGO (Nov. 22) - For the past two weeks, high school nurse Colleen Kahler has been on high alert. Her office,
which typically treats routine ailments such as sore throats, stomach aches and pulled muscles, has been transformed
into a screening center for an unlikely disease with a name that recalls a bygone era -- whooping cough.
Public Health Threat
According to the Centers for Disease Control and Prevention, there were more than 25,600 reported cases in 2005; the
true number may top 1 million annually. It killed 13 children, mostly infants, in 2003.
"We became a triage unit," says Kahler, health services coordinator at New Trier High School in Winnetka, Illinois, a tony
suburb of Chicago."The phones were literally ringing off the hook," she said. "We were fielding questions from parents,
physicians and students."Health experts said the New Trier outbreak underscores how whooping cough, a highly
contagious respiratory infection, remains a public health threat in the United States. According to the Centers for
Disease Control and Prevention, there were more than 25,600 reported cases in 2005; the true number may top 1
million annually.It killed 13 children, mostly infants, in 2003.Before immunizations became widespread, an average of
147,000 people in the United States developed whooping cough every year and 9,000 died.Whooping cough is common
in countries where children do not receive vaccinations -- 294,000 people worldwide died of the illness in 2002,
according to the World Health Organization.It is making a resurgence in other developed countries, such as Britain.
Germany began vaccinating teens against pertussis in 2000.An upswing of reported cases in the past decade is a
source of debate among health professionals, who attribute it both to waning immunity in teenagers and adults and
improved detection. Neither the vaccine, nor infection with the bacteria itself, offer lifelong protection.Beginning at two
months of age, babies get vaccinated against whooping cough, also known as pertussis, as part of an early childhood
immunization series that includes diphtheria and tetanus.Until last year, with the approval of a new type of vaccine for
people aged 11 to 64, adolescents only got a booster shot for diphtheria and tetanus because the vaccine used in
recent years was not approved for people over the age of 7 due to concern about possible side effects.
Tracking an Outbreak
New Trier had 26 confirmed cases of pertussis by November 16, or one third of all those reported in suburban Cook
County. The school's first case was detected in late August when students returned from summer break. There have
also been reports of sporadic cases at other high schools in the area.
Since early November, New Trier has been operating under directives from local health authorities to treat the situation
as an outbreak."If your child has a cough, please do not send him or her to school," the local health department said in
a letter to New Trier parents.New Trier has been trying to limit potential spread to other schools by canceling some
athletic and extra-curricular events, circulating fact sheets, letters and e-mails, and keeping a close watch on students,
faculty and staff for signs of the disease."We don't want to alarm everyone, so it's a big balancing act," said Dr.
Catherine Counard, assistant medical director for communicable disease control at the Cook County Department of
Public Health. "Whooping cough is a serious disease and we need to get this under control."Whooping cough is tricky to
diagnose because early symptoms are similar to other respiratory illnesses such as the common cold and bronchitis.
One telltale sign is a persistent dry cough. If detected early, the disease responds to antibiotics, but it is often diagnosed
late and must be left to run its course.Rarely life-threatening in teens or adults, small children are at risk for broken ribs,
pneumonia, and sometimes death. They typically get the disease from adults, making containment of an outbreak on the
scale of New Trier's critical.
Precautionary Measures
CDC now recommends that adolescents and adults get the new tetanus-diphtheria-pertussis booster instead of the
older vaccine that included only tetanus and diphtheria. At New Trier, most of the cases were among older students who
had not received the new shot.
"We now know that immunity to whooping cough wears off as we age," said Dr. Susan Rehm, medical director at the
National Foundation for Infectious Diseases. "The nice news is that this is preventable through vaccination."
As New Trier battles its outbreak, there have been reports of cases of whooping cough at Children's Hospital in Boston
and a high school in Palo Alto, California.
Trying to get a handle on the health status of more than 4,000 students spread over two school campuses has been no
small feat, New Trier's Kahler recalled. Anyone with a sustained cough -- teachers and staff included -- has been sent
home pending clearance from a doctor.
Kahler had to initially double her staff to six nurses and add a secretary just to keep up with extra paperwork, lab results,
student whereabouts, community outreach and the endless stream of phone calls.
Preventive measures at the school have ranged from subtle to humorous. A large container of Purell hand sanitizer and
Kleenex is now a staple in every classroom. Students were shown a film entitled "How to Do It In Your Sleeve," which
offers a primer on minimizing the spread of germs when coughing.
But despite the school's best efforts, the outbreak has not been easy on the local community. Many pediatricians were
not ready for the onslaught of requests for pertussis vaccine and parents have had difficulty seeking alternative sources.
"The numbers are much less now because the kids are getting cleared and getting treatment," said school
superintendent Linda Yonke. "I hope we're through the worst."
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