Lehigh County Health & Medicine Fall 2019 - 26

FEATURE

zoonotic pathogens as the control of disease in the animal reservoirs
themselves (SciTech Europa, 2018).
Vectorborne diseases, those diseases transmitted from a vector
to a species of concern. Vectors, including invertebrate species such
as flies, fleas, ticks, and mosquitoes, help to transmit infectious
diseases from one species to another. West Nile Virus (WNV),
mosquito-borne, and Lyme disease, tickborne, both occur within
Pennsylvania. It is paramount that we are able to recognize them
in various species and minimize risk factors to exposure whenever
possible. This is best done with a group approach, from various
angles including environmental control of the vectors, and the
prevention of disease occurrence in animals and in people, when
feasible.
Mosquito-borne Disease: In 1999 in NYC, WNV was first
brought to attention in the United States, not because of a new
understanding in human medicine but instead, due to sudden
massive bird die offs with subsequent neurologic illness noted
This concept, visually depicted in Figure 1, the "One Health in humans and horses. This vectorborne disease demonstrated
Umbrella," conceptualizes the scope and breadth of what en- the reach of the organism, the vector and the potential disease
compasses overall health and well-being, emphasizing the needed manifestations that were occurring in more than one species and
interdisciplinary cooperation, collaborations, and communications allowed us to determine the natural transmission seen in the enzootic
needed worldwide to ensure the overall health of the global society (sylvatic) cycles, the naturally occurring cycle between the vectors
(Lerner & Berg, 2015). This umbrella integrates environmental (mosquitoes) and the amplifying hosts (birds) (Staples & Fisher,
health, veterinary medicine, public health and human health. It 2016). From this we gained a better understanding of the parasite,
demonstrates the interconnected fields that span zoonotic diseases, its means of transmission and ways we can break the lifecycle to
antimicrobial resistance, biological threats, vector-borne diseases, prevent disease transmission or sustainability.
and more, under the holistic, all-inclusive umbrella of individual,
population and ecosystem health.
Tickborne Disease: Even more widespread concern has surrounded
the spread and increasing reach of Borrelia burgdorferi, the causative
Where then does the role of the veterinarian cross the public agent of Lyme Disease. The enzootic cycle is maintained between
health realm? Veterinarians' expertise and experience puts them at wild rodents, such as mice or squirrels, and ixodid ticks. Deer, often
the heart of key matters central to human health including concerns mischaracterized as the primary host and source of infection, serve
with antimicrobial and opioid use stewardship, food safety, and as a key maintenance species for the vector ticks, but are resistant
zoonotic diseases.
to infection. The adult ticks preferentially feed on them and thus,
deer serve a key role in the lifecycle of the parasite (Beard, 2016).
Three key arenas where veterinarians can play a pivotal role in the
overall public health of a community include concepts surrounding
Animals may be used as sentinels, indicators of the presence of
zoonotic disease prevention, control and education, second, those disease (Bowser & Anderson, 2018), such as the classic "canary in
same concepts as they relate to vector-borne diseases, and finally, the coal mine," for agro-terrorism indices, and for infectious and
the concept and benefits of animals as sentinels for diseases.
vectorborne diseases such as monitoring our dog populations for
Lyme disease incidence and wild birds for WNV and avian influenza
Zoonotic diseases, those diseases transmitted from animals to (Bowser & Anderson, 2018).
humans, are all too commonplace. They account for at least 60%
of all human pathogens (Monath, 2013) and 75% of all emerging
Animals have been used as sentinels for disease for a long time.
infectious diseases (Hincliffe, 2014). We can better combat these Since 1999 with WNV, surveillance using sentinel bird species has
diseases by considering various factors, in addition to understanding been used to determine exposure and viremia levels and determine
how diseases manifest clinically in humans. This will allow us to best level of risk in certain areas. Another sentinel that may be of use to
be able to prevent, control or even eradicate them. Factors include healthcare practitioners is that of Lyme Disease in dogs. In some
the parasite's life cycle, reservoir hosts, transmission modalities, counties in Pennsylvania seroprevalence of exposure to Borrelia
prevention measures and targets, and disease manifestation in burgdorferi can reach as high as 90% of the tested population
animals. Many see the key to the reduction of human exposure to though fewer than 10% often show clinical signs. According to
Figure 1: The 'One Health Umbrella' developed by the networks 'One Health Sweden' & 'One
Health Initiative' to illustrate the scope of the 'One Health concept'

26 Lehigh County Health & Medicine | FALL 2019

Lehigh County Health & Medicine Fall 2019

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