Page 91 - Journal of Special Operations Medicine - Winter 2014

Point Prevalence Survey for Tick-Borne Pathogens
in Military Working Dogs, Shelter Animals, and

Pet Populations in Northern Colombia

M. E. McCown, DVM, MPH, DACVPM; A. Alleman, DVM, PhD, DABVP, DACVP;
K. A. Sayler, PhD; R. Chandrashekar, PhD; B. Thatcher, BS; P. Tyrrell, BS;
B. Stillman, PhD; M. Beall, DVM, PhD; A. F. Barbet, PhD

ABSTRACT
Background: Based on the high tick-borne pathogen ehrlichiosis (Ehrlichia canis), Lyme disease (Borrelia
results from a 2011 surveillance study in three Colom- burgdorferi), and anaplasmosis (Anaplasma spp.) and
bian cities, an in-depth point prevalence survey was should be continually surveyed due to their veterinary
conducted to determine the seroprevalence of tick-borne and public health significance. The true value of ongo-
pathogens at a specific point in time in 70 working dogs, ing, continual surveillance for these and other diseases is
101 shelter dogs, and 47 client-owned dogs in Barran- the resultant decreased risk of disease exposure and oc-
quilla, Colombia. Results: Of the 218 serum samples, cupational and environmental hazards. 3,11–13 Additional
163 (74%) were positive for Ehrlichia canis and 116 value gained from surveillance studies is the disease prev-
(53%) for Anaplasma platys. Exposure to tick-borne alence rates in the local canine population, information
pathogens was highest in shelter and working dogs about the local vectors present, and the risk of disease
where more than 90% of the samples were seroposi- spread to the human population. This information is
tive or positive on polymerase chain reaction for one or critical to medical planners and public health leadership
more organisms as compared to 51% in client-owned for preserving the health of deployed Servicemembers
animals. Conclusion: Surveillance for exposure to tick- and working dogs.
borne pathogens provides vital information necessary to
protect and conserve the health of local humans and an- In a previous study, we presented preliminary data re-
imals, deployed military service members, and working garding the seroprevalence of Ehrlichia spp., Anaplasma
dogs in various parts of the world. This study and resul- spp., B. burgdorferi, and Dirofilaria immitis (heartworm
tant data demonstrate the value of following a broad- antigen prevalence) in dogs from three cities in Colom-
based surveillance study with a more specific, focused bia. The overall sample prevalence of heartworm and
10
analysis in an area of concern. This area’s high levels of seroprevalence of B. burgdorferi in the feral, shelter, and
exposure warrant emphasis by medical planners and ad- pet populations of dogs was quite low, 1.6% and 0%, re-
visors on precautionary measures for military dogs, Spe- spectively. However, the seroprevalence of Ehrlichia spp.
cial Operations Forces personnel, and the local public. and Anaplasma spp. in the three cities was alarmingly
high, at 62% and 33%, respectively. These data were
Keywords: tick-borne pathogens, point prevalence, surveil- collected using a point-of-care diagnostic test, IDEXX
®
®
lance, US Military SOF, military working dogs, Colombia SNAP 4Dx Plus Test (IDEXX Laboratories Inc., West-
brook, ME, USA; https://www.idexx.com). While very
sensitive in detecting antibodies to both Ehrlichia spp.
and Anaplasma spp., peptides used in this assay contain
Introduction
shared antigens that can result in cross-reactivity be-
Vector-borne diseases (VBD), and more specifically tick- tween antibodies to E. canis and E. chaffeensis as well
borne diseases, continue to increase over time in global as A. phagocytophilum and A. platys. 14–16 In addition,
distribution and emergence and are increasingly de- while our previous study defined exposure to Ehrlichia
1
scribed as primary causes of zoonotic and infectious spp. and Anaplasma spp., it did not indicate how many
diseases. Canine populations, susceptible to most of of the animals tested were actively infected (Figures 1–4).
2
the tick-borne pathogens that readily infect humans, are
documented reservoirs and sentinels for zoonotic and The objective of this work was to conduct a point
infectious diseases in many parts of the world. 3–10 Ca- prevalence survey in canines from Barranquilla, Colom-

nine diseases caused by tick-borne pathogens include bia, to determine seroprevalence and provide molecular

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