Biology Reference
In-Depth Information
advanced degrees in public health. Most local health departments, however,
are quite small; nationally, the median full-time staff size of local health
departments is 20 (range 1 to 21,700), and the majority serve jurisdictions
with fewer than 50,000 population (Fraser 1998). In some rural areas, the local
health department office may comprise a clerical staff member and an itiner-
ant public health nurse. The legal organization of local health departments
varies, from a centralized state health department with no independent local
health department jurisdictions to a fully decentralized system with rela-
tively autonomous local entities. The focus on individual patient care varies
from jurisdictions in which delivery to underserved populations is the para-
mount mission and highest priority to those that provide no clinical services
(and thus rely upon other aspects of the health care sector to make these
provisions). Not surprisingly, some local health departments function as a
key component in a well-integrated local system of community governance
that includes other agencies (e.g., hospitals, emergency medical services, and
emergency management) that would be called upon to respond to a disaster,
whereas other health departments have limited connectivity and interaction
with these response sectors.
Public health surveillance has been concisely characterized by CDC as “the
ongoing, systematic collection, analysis, and interpretation of health data
essential to the planning, implementation, and evaluation of public health
practice.” (CDC 1988). Despite nuanced attempts to refine this definition over
the years, this 1988 definition still holds, as does the old saw that, “all sur-
veillance is local,” a perspicacious phrase inspired by Tip O'Neill's prescient
commentary on our political system. Surveillance is locally grounded pri-
marily because the first inkling that something may be amiss typically arises
in proximity to its initial occurrence. Public health surveillance is also best
characterized as cyclical (Buckeridge and Cadieux 2007), with steps ranging
from identifying individual cases to detecting population patterns to con-
veying information for action (Figure 17.1).
With such a local focus and emphasis on actionable intelligence, the infec-
tion control practitioner at the community hospital will call the local health
department's communicable disease nurse after a patient who was seen in
the emergency department is belatedly diagnosed with measles. Or the local
child care operator will call the health department seeking information after
one of her staff members is diagnosed with a shigella infection. Or an astute
physician will suspect foul play when a blood culture comes back positive
for
B. anthracis
, the causative organism of anthrax (CDC 2001).
Detection signals may emerge from a variety of sources—telephone calls
from astute observers (e.g., the local infectious disease physician), clinical
laboratory reports, local newspaper articles on increased school absentee-
ism, and alerts generated by syndromic surveillance systems that are auto-
matically combing through electronic records from emergency departments.
Regardless of the source of the signal, the public health profession, largely
through the leadership of the CDC, has developed and adopted a robust
