Our
Research
Since l988,
the Lyme Disease Research Group at the Maine Medical Center Research
Institute has been conducting field studies, epidemiologic
surveys, and a vaccine trial to map the
expanding distribution in Maine of the Lyme disease vector
tick, to increase understanding of the environmental factors that influence
its spread, to explore methods of controlling the tick in nature
and to contribute data demonstrating the safety and effectiveness
of a new Lyme vaccine. We are also involved in research
studies of other tick-borne diseases and West Nile virus, which
is transmitted by mosquitoes. More details are provided by
a review of our publications.
Smith,
R. P. Jr., P. W. Rand and E. H. Lacombe.: Potential for
Lyme Disease in Maine: Deer survey of distribution of Ixodes dammini,
the tick vector. Am
J Public Health, 80:333-335, 1990.
This study
first revealed that deer were hosting ticks in southern Maine.
Rand,
P. W., Smith, R. P. Jr., and E. H. Lacombe: Canine seroprevalence
and the distribution of Ixodes dammini in an area of emerging
Lyme disease. Am
J. Public Health, 81:1331-1334, 1991.
This study, involving
16 veterinary clinics statewide and over 800 dogs, demonstrated
that the Lyme bacteria was being transmitted to dogs within twenty
miles of the Maine coast along its entire length.
Smith,
R. P. Jr., E. H. Lacombe, P. W. Rand, and R. Dearborn: Diversity
of tick species biting humans in an emerging area for Lyme disease.
Am
J Public Health, 82:66-69, 1992.
Of 709
human biting ticks submitted from Maine in 1989 and 1990,
17% were I.dammini, 34% were I.cookei, the
woodchuck tick, and 45% were dog ticks, Dermacentor
variabilis.
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Lacombe,
E. H., P. W. Rand, and R. P. Smith, Jr.: Disparity of Borrelia
burgdorferi infection rates of adult Ixodes dammini on deer
and vegetation. J Infect Dis, 167:1236-1238, 1993.
The
infection rate in feeding adult ticks removed from deer was 13%,
while the infection rate among questing adult at the same location
was 47%. The
cause of this reduction remains to be discovered.
 Rand,
P. W., E. H. Lacombe, R. P. Smith, Jr., S. M. Rich, C. W.
Kilpatrick, C. A. Dragoni, and D. Caporale: Competence of Peromyscus
maniculatus (Rodentia: Cricetidae) as a reservoir host for
Borrelia burgdorferi (Spirochaetares: Spirochaetaceae)
in the wild. J Med Entomol, 30: 614-618, 1993.
This
study demonstrated, on an island where they were the only
species of mouse present, that deer mice were competent
reservoir hosts for the bacteria that causes Lyme disease.
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Caporale,
D. A., T. D. Kocher, R. P. Smith, Jr., P. W. Rand, and E. H. Lacombe:
OspB sequence variation of Borrelia burgdorferi along the coast
of Maine. Proceedings of the 2nd European Symposium on Lyme Disease.
Ann Rheum Dis, 52:408, 1993.
Using
PCR and DNA sequencing, 7 unique OspB gene sequences were found among
5l isolates of B. burgdorferi from five sites along the
Maine coast. Multiple strains of the bacteria were found at individual
sites and within tissues from a single rat.
Smith,
R. P., Jr., P. W. Rand, E. H. Lacombe, S. R. Telford, III, S. M. Rich,
J. Piesman, and A. Spielman: Norway rats as reservoir hosts for Lyme
disease spirochetes on Monhegan Island, Maine. J
Infect Dis, 168:687-691, 1993.
For the
first time, it was shown that Norway rats are very competent reservoir
hosts of the agent of Lyme disease.
Rand,
P. W., E. H. Lacombe, R. P. Smith, Jr., K. Gensheimer, and D. T. Dennis:
Low seroprevalence of human Lyme disease near a focus of high entomolgic
risk. Am J Trop Med Hyg 55:160-164, 1996.
Within
a 5km x 8km area, a strong correlation existed between deer sightings
and canine Lyme sero-positivity, which was 100% near the coast. Despite
the high risk of exposure near the coast, only 2 of 272 persons were
seropositive.
 Smith,
R. P. Jr., P. W. Rand, E. H. Lacombe, S. R. Morris, D. W. Holmes, and
D. A. Caporale: Role of bird migration in the long-distance
dispersal of Ixodes dammini, the vector of Lyme disease. J
Infect Dis 174:221-224, 1996.
From 1989
through 1994,1.2% of 11,324 spring-migrating birds and 0.2% of
8607 fall-migrating birds, mist-netted on a small, isolated, offshore
island where the tick is not established were infested with Ixodes
dammini. Twenty percent of nymphal ticks were infected.
Rand,
P. W., E. H. Lacombe, R. P. Smith, Jr., and J. Ficker: Participation
of birds (Aves) in the emergence of Lyme disease in southern Maine:
J
Med Entomol 35(3):270-276, 1998.
Over 2600
larval and nymphal deer ticks were removed from 1713 of 1972 passerine
birds during nesting seasons in south coastal Maine from 1989 through
1996. Twenty five of 64 species were infested, and certain of
these species were reservoir competent while others were not.
Kierans,
J. E., and E. H. Lacombe: First records of Amblyomma americanum,
Ixodes (Ixodes) dentatus, and Ixodes (Ceratixodes)
uriae (Acari: Ixodidae) from Maine. J.
Parasitol., 84(3): 629-631, 1998.
The records
of three ixodid tick species in the State of Maine are reported.
Amblyomma americanum, common in States to the south, is a potential
vector of a different Borrelia species and monocytic ehrlichiosis.
In Scandinavia, Ixodes uriae, which is found on puffins and
other seabirds, has been shown to carry the Lyme disease spirochete.
This is the first report of I. uriae in eastern United
States. Dr. J. E. Keirans is the curator of the U. S. National
Tick Collection at Georgia Southern University, Statesboro, GA.
Lacombe,
E. H., P. W. Rand, and R. P. Smith, Jr.: Severe reaction in domestic
animals following the bite of Ixodes muris (Acari: Ixodidae)
ticks. J
Med Entomol. 36(3):227-232,1999.
This paper
reports 43 cases of severe pain and swelling accompanied by lethargy,
anorexia and fever in 42 dogs and cats and 1 goat following the bite
of this tick.
Dolan,
M. C., E. H. Lacombe, and J. Piesman: Vector Competence of Ixodes
muris (Acari: Ixodidae) for Borrelia burgdorferi. J
Med Entomol. 37(5):766-768,2000.
This paper
discusses the vector competence of Ixodes muris for Borrelia
burgdorferi.
Rand,
P. W., E. H. Lacombe, M. S. Holman, C. Lubelczyk and R. P. Smith, Jr.:
Attempt to control ticks (Acari: Ixodidae) on deer on an isolated island
using Ivermectin-treated corn. J
Med. Entomol. 37(1):126-133, 2000.
This paper describes
a three-year effort to control ticks by feeding deer corn laced with
an acaricide on Monhegan Island, Maine.
Monhegan Island.
Robert
P. Smith, MD, MPH; Robert T. Schoen, MD; Daniel W. Rahn, MD; Vijay K.
Sikand, MD; John Nowakowski, MD; Dennis L. Parenti, MD; Mary S. Holman,
BA, David H. Persing, MD, PhD; and Allen C. Steere, MD: Clinical Characteristics
and Treatment Outcome of Early Lyme Disease in Patients with Microbiologically
Confirmed Erythema Migrans. Annals
of Internal Medicine136(6):421-428, 2002.
This study was
designed to describe the early signs and symptoms of Lyme disease.
Researchers followed almost 11,000 people in a study to test a Lyme
disease vaccine in 10 states where Lyme disease frequently occurs.
Of these, 118 had Lyme disease that was documented with special tests
for infection. The patients had visited their physicians a few days
after the appearance of a red rash. The rash usually had the same
color throughout (59%) or was redder in the center (32%). Only 9%
of the rashes had a clear area in the middle ("classic" Lyme disease
rash). About 1/3 of the patents also reported flu-like symptoms such
as muscle and joint pains and headache. Rashes and symptoms usually
went away with antibiotic treatment.
Courtney,T.,
S. Sears, J. Woytowicz, D. Preston , R. Smith, P. Rand, E. Lacombe,
M. Holman, et al: Outbreak of Powassan encephalitis in Maine and Vermont
1999-2001. MMWR
50(35):761-764, 2001.
This paper reports on three cases of Powassan virus resulting in encephalitis,
acquired in-state by Maine residents, in 2000 and 2001.
Rand, P.W., C. Lubelczyk, G.R. Lavigne, S. Elias, M.S.
Holman, E.H. Lacombe, and R.P. Smith: Deer density and abundance
of Ixodes scapularis (Acari:Ixodidae). J
Med Entomol 40(2): 179-184, 2003.
This
paper demonstrated the relationship between deer presence
as measured by pellet group counts and adult deer tick abundance
on study plots in southern Maine in 1998 -2000. Few ticks
were collected at deer densities <7/km2.
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Goethert,
H.K., C. Lubelczyk, E. Lacombe, M. Holman, P. Rand, R.P. Smith, S.R.Telford
III : Enzootic Babesia microti in Maine. J
Parasitol 89(5): 1069-1071, 2003.
The agent of human
babesiosis exists in mammals in areas of coastal Maine where deer ticks
are rare or non-existent. Two forms of B. microti were demonstrated
by phylogenetic analysis.
Lyme Borreliosis: Biology, Epidemiology, and Control. Clinical Infectious
Diseases (37) 1724-6, 2003
This
publication represents a book review by Dr. Smith that was published
in Clinical Infectious Diseases.
Holman,
M.S, D.A. Caporale, J. Goldberg, E.Lacombe, C. Lubelczyk, P.W. Rand,
and R.P. Smith: Anaplasma phagocytophilum, Babesia microti,
and Borrelia burgdorferi in Ixodes scapularis, Southern
Coastal Maine. EID
10(4):744-746, 2004.
The agents of two other deer
tick transmitted diseases, babesiosis and human granulocytic ehrlichiosis,
were discovered in Maine deer ticks, using polymerase chain reaction.
Small numbers of ticks were shown to be co-infected.
Rand,
P.W., M.S. Holman, C. Lubelcyzk, E.L. Lacombe, A.T. DeGaetano and R.P.
Smith: Thermal Accumulation and the early development of Ixodes
scapularis. J
Vector Ecol 29(1):164-176, 2004.
Degree
day data were collected in natural settings at sites throughout Maine
as engorged female deer ticks developed and laid eggs and those eggs
hatched out larvae. Maps were constructed to demonstrate areas in the
northeastern U.S. where temperatures were potentially sufficient for
Ixodes scapularis larvae to be produced.
Rand
P.W., C. Lubelczyk, M.S. Holman, E.H. Lacombe, and R.P. Smith: Abundance
of Ixodes scapularis (Acari:Ixodidae) after the complete removal
of deer from an isolated offshore island, endemic for Lyme disease.
J.
Med. Entomol. 41(4):779-784, 2004.
This
paper tracks the decline of an established population of deer ticks
on Monhegan Island after the deer herd was completely removed in the
late 1990s.
Lubelczyk
C, S. P. Elias, P.W. Rand, M.S. Holman, E.H. Lacombe, and R.P. Smith,
Jr.: Habitat associations of Ixodes scapularis (Acari:Ixodidae)
in Maine. Environ.
Entomol. 33(4): 900-906, 2004.
In
1998 - 2000, at three sites in coastal Maine, deer ticks were found
more often in study sites that had a shrub layer, deciduous leaf litter,
forest grasses, moist-soil ferns and greater than 50% tree canopy closure
than in study sites that lacked those features.
 Stone
E.G., E.H. Lacombe, and P.W. Rand: Antibody Testing and Lyme Disease
Risk. Emerg
Inf Dis. 11(5):722-724, 2005
This study examined >9000 dogs for antibodies to Lyme disease using
the IDEXX 3Dx kit. Positive dog samples correlated with the current
distribution of deer ticks and cases of human Lyme disease in Maine.
Holman,
M.S., R.F. Darsie, Jr., and K.A. Foss. A checklist of the mosquitoes
of Maine with new state records. J
Amer Mosq Con Assoc. 22 (2): 327-329, 2006.
This
paper updates current species of mosquitoes found in Maine.
Smith
R.P. Current diagnosis and treatment of Lyme disease. Comp
Ther. 31(4): 284-290, 2005.
This
paper reviews the presentation and treatment of human Lyme disease along
with the role of serological testing in detection.
 Elias
S. P., C.B. Lubelczyk, P.W. Rand, E.H. Lacombe, M.S. Holman, and R.P.
Smith Jr.: Deer browse resistant exotic-invasive understory: an indicator
of elevated human risk of exposure to Ixodes scapularis (Acari: Ixodidae)
in southern coastal Maine woodlands. J
Med Entomol. 43(6):1142-52, 2006.
An association of habitat features with the abundance
of ticks was made showing landscape changes, including the invasion
by exotic vegetation, might create favorable tick habitat. These findings
could prove helpful in assessing local risk of exposure to this vector
tick.
Smith,
R.P. Jr, S. Bin Muzaffar, J. Lavers, E.H. Lacombe, B.K. Cahill, C.B.
Lubelczyk, A. Kinsler, A.J. Mathers, and P.W. Rand. Borrelia garinii
in Seabird Ticks (Ixodes uriae), Atlantic Coast, North America. Emerg.
Inf. Dis. 12(12):1909-1912, 2006.
Describes
the first report of Borrelia garinii, a European strain of the agent
of Lyme disease, in North America and discusses the potential public
health implications of this finding.
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Lubelczyk,
C., T. Hanson, E. Lacombe, M. Holman, and J. Keirans. First United
States record of the hard tick Ixodes (Pholeoixodes) gregsoni
Lindquist, Wu, and Redner. J. of Parasitol. 93(3), 2007.
This study reports the first U.S. record of this tick species obtained from
mustelids and domestic animals in Vermont and Maine.
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P.W.
Rand, E.H. Lacombe, R. Dearborn, B.K.Cahill, S. P. Elias, C. Lubelczyk,
G.A.Beckett and R.P. Smith, Jr.: Passive Surveillance in Maine, an Area
Emergent for Tick-Borne Diseases.
J. Med. Entomol. 44(6): 11118-1129 (2007)
This
paper summarizes data from 18 continuous years of tick sumissions within
the State of Maine.
For
more information, please contact Dr. Peter Rand and the Lyme Disease
Research staff at:
Vector-borne Disease Laboratory
Maine Medical Center Research Institute
75 John Roberts Rd., Suite 9B
South Portland, ME 04106
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