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The prevalence of co-infections among Ixodes scapularis
harvested from freshly slain deer
Paul N. Williams, Dept. of Biology, York College, York, PA 17405
http://cornellcollege.edu/biology/insects2005/images/
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Abstract
The white-tailed deer is recognized as a reproductive-stage host of the deer tick
Ixodes scapularis, a known vector for several pathogenic organisms. One of
these organisms is Borrelia burgdorferi, the causative agent of Lyme disease, the
most commonly reported vector-borne illness in the United States. Additionally,
Ixodes is a known vector for Babesia microti, Bartonella henselae, and
Anaplasma phagocytophila, the causative agents of babesiosis, cat-scratch
disease, and human granulocytic ehrlichiosis respectively. The presence and
transmission of co-infections of these organisms can complicate diagnosis and
result in a more severe clinical progression of disease. The objective of this study
was the determination of the rates of co-infection of the above organisms in
Ixodes found on deer that had been recently slain by hunters. Ticks were
harvested over a two day period and PCR was performed to determine the
presence of the respective organisms. Additionally, PCR detection of Ixodes was
run as an internal control. To date, of 20 examined ticks, one is suspected to
have been a vector for both Borrelia and Babesia, while another has been
confirmed as a vector for Anaplasma phagocytohpila.
Introduction
Lyme disease, caused by the spirochete Borrelia
burgdorferi, is the most commonly reported
vector borne illness in the United States (CDC
2002). Its primary invertebrate vector is the
deer tick Ixodes scapularis. Complicating both
the diagnosis and prognosis of Lyme disease is
the possibility of co-infections with other
organisms that utilize Ixodes as a vector.
Among the most prevalent of these organisms
are Anaplasma phagocytophila, the causative
agent of Human Granulocytic Ehrlichiosis,
Babesia microti, the organism responsible for
babesiosis, and Bartonella henselae, which
causes the illness often referred to as “catscratch disease.” In addition to sharing Ixodes
as a vector, each of these pathogens can
potentially
take
advantage
of
the
immunocompromise that accompanies Lyme
disease (Adelson et al. 2004).
A
A
B
A
A
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B
http://www.lyme.org/gallery/babe-miles1
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Results
275 bp
Photo by Willy Burgdorfer
C
•Electrophoresis failed to confirm the
identity of Ixodes in many of the
samples
D
http://en.wikipedia.org/wiki/Endocarditis
http://www.marvistavet.com/html/body_ehrlich
ia_infection_in_dogs.html
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Figure 1. Micrographs of A) Borrelia burgdorferi,
B) Babesia microti, C) Bartonella henselae, and D)
Anaplasma phagocytophila.
C C
D D
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Methods
Harvest ticks from
slain deer
Extracted DNA
using Dneasy kit
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C
presence
of
Anaplasma
phagocytophila was confirmed in a
separate deer tick
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D
Discussion
238 bp
185 bp
238 bp
E
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Performed PCR
using primers
from literature
•There is the possibility of co-infection
with Borrelia and Babesia in one of the
ticks sampled
•The
185 bp
E
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546 bp
The absence of expected bands in the
Ixodes gel suggests that either DNA
extraction or PCR was not entirely effective.
However, discernible bands for both Borrelia
and Babesia are present in a single tick
sample, suggesting the possibility of coinfection.
Additionally, nested PCR for
Anaplasma revealed an appropriately placed
band for one of the ticks, which is strongly
indicative of infection. DNA sequencing will
be used to confirm. A comparatively small
sample size and the possibility of inefficient
extraction may have contributed to lessthan expected rates of infection.
Literature cited
Performed
electrophoresis
using 8%
agarose gel
Objective:
To determine the prevalence of
co-infections in ticks found on locally
slain deer.
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Gel
analysis
using
AlphaEase
software
CDC. 2002. Lyme Disease– United States 2000. MMWR 50:19-31.
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Figure 2. Electrophoresis of PCR product from DNA
extracted from A) Ixodes scapularis, B) Borrelia
burgdorferi, C) Babesia microti, D) Bartonella
henselae, and E) Anaplasma phagocytophila. Arrows
indicate expected base pair size for each sample. In
each gel, lanes 2-10 from the top wells and lanes 211 from the bottom wells represent DNA extracted
from individual ticks.
Adelson, M.E., Rao, R., Tilton, R. C., Cabets, K., Eskow, E., Fein, L.,
Occi, J., and Mordechai, E. 2004. Prevalence of Borrelia
burgdorferi, Bartonella spp., Babesia microti, and Anaplasma
phagocytophila in Ixodes scapularis ticks collected in northern
New Jersey. Journal of Clinical Microbiology 42(6): 27992801.
Acknowledgments
The author would like to thank Carolyn Mathur, PhD and Richard
Daly, MD, for their assistance in the design of this project, the good
people of the Windsor Meat Market for the use of their facilities,
Jeffrey Thompson, PhD and Ronald Kaltreider, PhD, for their
assistance in the molecular biology bits, and Karl Kleiner, PhD, for
his constructive criticism and general oversight of the project.