Ecology and Virulence o f
Legionnaire's Disease Bacteri a
in Aquatic Habitats
Near Mt . St . Helen s
by
David L . Tiso n
Ramon J . Seidle r
Water Resources Research Institut e
Oregon State Universit y
Corvallis, Orego n
WRRI-84
September 1983
ECOLOGY AND VIRULENCE OF LEGIONNAIR E ' S DISEASE BACTERI A
IN AQUATIC HABITATS NEAR MT . ST . HELEN S
by
David L . Tison and Ramon J . Seidle r
Department of Microbiology, Oregon State Universit y
Final Technical Completion Repor t
for Project No . A-060-OR E
to
United States Department of the Interio r
Washington, D .C . 2024 0
Project Sponsored by :
Water Resources Research Institut e
Oregon State Universit y
Corvallis, Oregon 9733 1
The research upon which this report is based was financed in part by th e
U .S . Department of the Interior, Washington, D .C . (Project No . A-060-ORE) ,
as authorized by the Water Research and Development Act of 1978, P .L . 95-467 .
Contents of this publication do not necessarily reflect the views an d
policies of the U .S . Department of the Interior, nor does mention of trad e
names or commercial products constitute their endorsement or recommendatio n
for use by the United States Government .
WRRI-84
September 1983
ABSTRACT
Illnesses among researchers exposed to lakes and streams i n
the Mt . St . Helens blast zone after the 18 May 1980 eruptio n
prompted us to determine the occurrence and potential virulenc e
of Legionella (Legionnaire's disease bacteria) in aquati c
habitats near Mt . St . Helens during the summers of 198 .
1 and 1982 .
Concentrations of L . pneumophila, L . nnicdadei, L . g©rmanii, L .
dumoffii, and L . bozemanii, determined by microscopic count s
using direct immunofluorescent staining, ranged from <l0 4 to 10'
cells/L in lakes and rivers outside of the Mt . St . Helens blas t
zone while the numbers of Legionella in aquatic habitats insid e
the blast zone were from 10 5 to 10 7 cells/L .
Legionella number s
were consistently highest in N . Coldwater and Spirit lakes, whic h
received water from hydrothermal seeps . Legionella pneumophil a
serogroups 4 and 6 were isolated from N . Coldwater Lake in 198 1
and from S . Coldwater Creek in 1982, indicating that th e
potentially virulent strains of Legionella persist in aquati c
habitats in the blast zone of Mt . St . Helens .
FOREWORD
The Water Resources Research Institute, located on the Orego n
State University campus, serves the State of Oregon . Th e
Institute fosters, encourages and facilitates water resource s
research and education involving all aspects of the quality an d
quantity of water available for beneficial use . The Institute
administers and coordinates statewide and regional programs o f
multidisciplinary research in water and related land resources .
The Institute provides a necessary communications an d
coordination link between the agencies of local, state an d
federal government, as well as the private sector, and the broa d
research community at universities in the state on matters o f
water-related research . The Institute also coordinates th e
inter-disciplinary program of graduate education in wate r
resources at Oregon State University .
It is Institute policy to make available the results o f
significant water-related research conducted in Oregon' s
universities and colleges . The Institute neither endorses no r
rejects the findings of the authors of such research . It doe s
recommend careful consideration of the accumulated facts by thos e
concerned with the solution of water-related problems .
ACKNOWLEDGEMENT S
We thank Cliff Dahm (Oregon State University) and Jim Bedel l
(U .S . Forest Service) for assistance in coordinating sampl e
collection and for helpful discussions . The U .S .. Forest Servic e
is thanked for providing helicopter time . Financial support wa s
provided by the Oregon State University Department of Laborator y
Animal Resources and the U .S . Department of the Interior, Offic e
of Water Policy, through the Water Resources Research Institut e
at Oregon State University .
11
TABLE OF CONTENTS
Pag e
INTRODUCTION
1
MATERIALS AND METHODS
3
RESULTS
7
DISCUSSION
9
REFERENCES
11
LIST OF FIGURES
Page
Figure 1 . Mt . St . Helens and vicinity, showing river s
and lakes affected by May 18, 1980 eruption
4
Figure 2 . Diagrammatic representation of a sample are a
in the S . Coldwater Creek drainage area Figure 3 .
5
A portion of the S . Coldwater Creek drainag e
area illustrated in Figure 2 6
LIST OF TABLE S
Table 1 .
Numbers of cells per liter reacting wit h
serogroup specific fluorescent antibod y
conjugates to Legionella spp
iv
7
INTRODUCTION
The eruption of Mt . St . Helens on May 18, 1980 reshape d
nearby pre-existing lakes and streams, created new lakes as a
result of damming of drainages by debris flows, and produce d
numerous hydrothermal seeps . Tremendous quantities of pyrolize .d
organic matter from the destroyed forest and inorganic nutrient s
from the ash and pyroclastics were added to previousl y
oligotrophic sub-alpine lakes typical of those in the Cascad e
Range in the Pacific Northwest U . S . These aquatic environment s
progressed from oligotrophic to hypereutrophic in a matter o f
days ; undisturbed, this progression would have taken centuries .
Because of the proximity of academic research institutions t o
these unique environments, characterization of the chemical an d
biological properties of thes e ' habitats was initiated soon afte r
the May 18, 1980 eruption (1, 7, 9) .
Research personnel exposed to aquatic environments in the Mt .
St . Helens blast zone reported illnesses with "flu-like" symptom s
throughout the summer of 1980 and again early in the spring o f
1981 . The similarity of the reported symptoms to . the "Pontia c
Fever" syndrome cause by Legionella'pneumophila and the nature o f
the aquatic environments produced by the cataclysmic eruption o f
Mt . St . Helens prompted us to initiate a study to determine th e
density and distribution of Legionella spp. (the etiologic agent s
of Legionnaires'• Disease and Pontiac Fever) in the blast zone o f
Mt . St . Helens .
MATERIALS AND METHOD S
The degree of impact by the May 18, 1980 eruption on lake s
and streams in the Mt . St . Helens blast zone is shown in Figur e
1 . Sites sampled included spirit Lake, North Coldwater an d
Castle creeks, which are in the scorch zone, and Ryan Lake, whic h
is in the blowdown zone . South Coldwater Creek and hydrotherma l
seeps in the South Coldwater drainage area and sites outside o f
the blast zone including McBride Lake, Silver Lake (not shown )
and the Muddy and North Toutle rivers were also sampled . Figure s
2 and 3 illustrate the nature of the South Coldwater Cree k
drainage area .
The physical, chemical and biological characteristics o f
these sites have been described previously (1, 7, 9) . In
general, lakes in the blast zone were high in dissolved organi c
carbon (DOC), nitrogen-limited, and dominated by heterotrophi c
and metal oxidizing bacteria with total direct microscopic count s
ranging from 10 6 to 1Q 8 bacteria per ml (1, . .7, 9) .
One-to-four ]n iters of water were colleeted, concemtr-ate ;d by
membrane filtration (6), and examined microscopically usin g
direct immnn, 0fluorescence (3) .
Cells
reacting with fluorescen t
antibody conjugates (Biological Products Section, , .enters fo r
Disease Control) specific for L . pneumophila ser®groups
micdadei, L . gormanii, L .
dumoffii, and L . bozemanii wer e
quantitated . The virulence of presumptive Legionella was
assessed by guinea pig innoculation (5) .
L,
Figure 1 . Mt . St . Helens and vicinity, showing rivers and lake s
affected by May 18, 1980 eruption .
4
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RESULT S
Concentrations of Legionella species from the most
intensively sampled sites are presented in Table 1 .
The numbers
of Legionella spp . in Ryan and Castle Creek lakes are of the sam e
order of magnitude as those found for L . pneumophila in a survey
of a number of lakes and rivers in the southeastern United State s
(4) . Concentrations of Legionella spp . in North Coldwater an d
Spirit lakes were consistently high (10 6 to 107 cells/L) whe n
compared to lakes outside of the blast zone (Table 1) . These
data may be attributed to the high concentrations of DOC an d
available metals in these lakes . Although the concentrations o f
Legionella spp . were particularly high in North Coldwater an d
Spirit lakes, the percentage of the total bacterial populatio n
these bacteria comprised (0 .1% to 1%) was not unusual whe n
compared to other aquatic habitats (4) . The enrichment of thes e
aquatic environments with DOC from pyrolysis of the productiv e
coniferous forest and inputs of inorganic nutrients from the as h
and pyroclastics have enriched for not only Legionella but the
total bacterial population as well .
Legionella pneumophila serogroups 4 and 6 were isolated o n
BCYE agar inoculated with the liver, spleen and peritoneal flui d
at necropsy from animals inoculated with concentrated water fro m
North Coldwater Lake collected on April 30, 1981 and from Sout h
Coldwater Creek collected on June 15, 19 .82 .. These isolates wer e
characterized biochemically and serologically as describe d
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DISCUSSION
The concentrations of Legionella spp . in hydrothermal seep s
in the South Coldwater Creek drainage particularly emphasize th e
enrichment potential of aquatic niches in this area . Therma l
seeps eminating from the mud flow ranged in temperature from 7 50 C
to ambient (18 0 C) . Dissolved organic carbon concentration s
ranged from about 700 to 900 mg C/L in seeps having temperature s
above 65 0 C while concentrations in thermal seeps wit h
temperatures from 40 to 60 0 C were about 250 mg C/L (C . Dahm ,
pers . comm .) . Microbial communities similar to those in natura l
thermal springs (2) and man-made thermal habitats (8) wer e
observed . At temperatures above 40 0C these communities wer e
comprised mainly of the cyanobacteria .Phormidium.sp ., and to a
lesser extent, Oscillitoria sp ., and associate d
non-photosynthetic bacteria . Concentrations of Legionella spp .
ranged from 105 to 10 7 DFA positive cells per cm . It i s
interesting to note that those lakes in the Mt . St . Helens blas t
zone found to harbor the highest densities of Legionella, North
Coldwater and Spirit, were the only lakes receiving waters fro m
thermal seeps . These observations suggest that enriched therma l
waters which foster microbial communities with hig h
concentrations of biomass may act as source of Legionella wher e
these bacteria may proliferate during favorable seasona l
conditions in non-thermal waters such as Spirit and Nort h
Coldwater lakes .
9
Legionella species were observed in rivers and lakes in th e
Mt . St . Helens blast zone in concentrations similar to thos e
found in other aquatic habitats outside of the blast zone excep t
at hydrothermal seeps in the South Coldwater Creek drainage ,
North Coldwater Lake and Spirit Lake . The concentrations o f
Legionella in those warmer waters were consistently one to tw o
orders of magnitude higher than those found elsewhere . Virulent
strains of L . pneumophila were isolated during both season s
sampled ; however, illnesses among workers exposed to aquati c
habitats in the Mt . St . Helens blast zone were not confirmed a s
legionnellosis . The high concentrations of Legionella in water s
in the blast zone (10 7 cells/L) are diluted significantly a s
these waters flow to populated areas, as shown by the low number s
found in the North Toutle River (10 4 cells/L) outside of th e
blast zone .
10
REFERENCE S
1.
Baross, J .A., C .N . Dahm, A .R . Ward, M .D . ',they, and
J . R . Sedell . 1982 . Initial microbiological respons e
in lakes to the Mt . St . Helens eruption . Nature .
296 : 49-52 .
2.
Brock, T .D . 1978 . Thermophilic Microorganisms an d
Life at High Temperatures . Springer-Verlag, New York .
3.
Cherry, W .B ., B . Pittman, P .P . Harris, G .A . Hebert ,
B .M . Thomason, L . Thacker, and R .E . Weaver . 1978 .
Detection of Legionnaires' disease bacteria by direc t
immunofluorescent staining . J . Clin . Microbiol . 8 :
329-338 .
4.
Fliermans, C .B ., W .B . Cherry, L .H . Orrison, S .J . Smith ,
D .L . Tison, and D .H . Pope . 1981 Ecological distributio n
of Legionella pneumophila . Appl . Environm . Microbiol .
41 : 9-16 .
5.
McDade, J .E . 1979 . Primary isolation using guinea pig s
and embyonated eggs . In : G .L . Jones and G .A . Hebert, eds .
"Legionnaires" the disease, the bacterium and methodology .
U .S . Dept . of Health, Education and Welfare, Centers for
Disease Control, Atlanta, Ga .
6.
Orrison, L .H ., W .B . Cherry, C .B . Fliermans, S .B . Dees ,
L .K . McDougal and D .J . Dodd . 1981 . Characteristics
of environmental isolates of Leqionella pneumophila .
Appl . Environm . Microbial . 42 : 109-115 .
7.
Staley, J .T ., L .G . Lehmicke, F .E . Palmer, R .W . Peet, and
R .C . Wissmar . 1982 . Impact of Mt . St . Helens eruptio n
on bacteriology of lakes in the blast zone . Appl .
Environm . Microbial . 43 : 664-670 .
8.
Tison, D .L ., D .H . Pope, W .B . Cherry and C .B . Fliermans .
1980 . Growth of Leqionella pneumophila in associatio n
with blue-green algae (cyanobacteria) . Appl .. Environm .
Microbial . 39 : 456-459 .
9.
Wissman, R .C ., A .H . Devol, J .T . Staley, and J .R . Sedell .
1982 . Biological responses of lakes within the Moun t
St . Helens blast zone . Science . 216 : 175-181 .
"1I