Biomedical Engineering Reference
In-Depth Information
performed, and the type of facilities being utilized need to
be considered when establishing, sustaining, and evaluating
a preventive medicine program. Additionally, trainers,
colony managers, behaviorists, compliance officers, and
maintenance personnel must be consulted during the
creation and evaluation phases of any preventive medicine
program.
The cornerstone of a good preventive medicine program
is an exemplary veterinary care component, but this is only
one part of a complicated puzzle involving occupational
health and safety, quarantine procedures, husbandry, disease
surveillance and prevention, environmental enrichment, and
physical plant components.
a strong delayed type hypersensitivity in those currently
infected with M. tuberculosis. The TST should be admin-
istered to all potential NHP workers to assist in the iden-
tification of individuals with active TB infections and to
establish a baseline TST response that can be compared to
subsequent responses.
Potential employees with a positive TST on initial
screening and without a history of positive TST or
previous BCG vaccination should be referred immedi-
ately to a health care professional as they may have an
active mycobacterial infection. These employees should
be prevented from animal contact until cleared by their
physicians and deemed noninfectious. Generally, a chest
radiograph is used to identify active TB disease. If the
chest radiograph is normal, additional diagnostics can be
performed including blood assays for M. tuberculosis,or
the person can be treated for
OCCUPATIONAL HEALTH AND SAFETY
While the close phylogenetic relationship between NHPs
and humans affords numerous benefits for researchers, it
unfortunately provides unique challenges to the primate
veterinarian. Most concerning, NHPs readily transmit
a variety of zoonotic diseases to their caretakers. A thor-
ough review of zoonotic diseases transmitted by NHPs can
be found elsewhere in this topic.
Just as importantly from a colony health perspective,
captive NHPs are exposed to a wide variety of anthro-
pozoonoses. These include, but are not limited to, Myco-
bacterium tuberculosis, measles virus (
Potkay et al., 1966;
Levy and Mirkovic, 1971; Hime et al., 1975; Remfry, 1976;
Montrey et al., 1980
), and human herpes virus (
Melendez
et al., 1969; Matz-Rensing et al., 2003; Landolfi et al.,
2005
). NHP exposure can have devastating consequences
for individual animals and entire colonies. Thus, a thorough
preventive medicine program should include a comprehen-
sive workplace occupational health and safety program that
incorporates personnel health surveillance, staff disease
prophylaxis and vaccination, and staff training.
latent
tuberculosis
infection.
Ideally, potential employees with a negative TST on
initial screening should undergo another TST one to three
weeks later as part of a two-step TST (
Jensen et al., 2005
).
A positive reaction on the second test after a negative first
test is attributed to a “booster” reaction in which a person's
TST reactivity is stimulated by serial testing and is indic-
ative of past infection with M. tuberculosis, current infec-
tion with a nontuberculous mycobacterium, or previous
BCG vaccination (
Thompson et al., 1979; Jensen et al.,
2005
). Consultation with a health care professional for
employees who test positive on the second test is war-
ranted; however, the true benefit of this approach is in
interpretation of future skin tests and preventing the inter-
pretation of positive TST reactions in those whose hyper-
sensitivity reaction is the result of a booster reaction and
not recent TB infection.
Discovering that a person is TST positive prior to
employment enables occupational health professionals to
tailor future surveillance regimens for these individuals.
CDC guidelines recommend that individuals who are
positive on their second step test should receive one chest
radiograph to exclude the possibility of TB disease.
Subsequently, personnel who are skin test positive but
M. tuberculosis free should be screened at least annually for
symptoms. Frequency of symptomatic screening should be
judged based on a careful risk assessment including factors
such as the potential risk to the colony, local environmental
and community factors which may play a role in TB
exposure for employees, and the research program at the
institution. These individuals should be thoroughly
educated about the symptoms of active M. tuberculosis
infection and should be trained to report any evidence of
disease to their facility's occupational health unit. This
strategy eliminates the need for unnecessary serial radio-
graphs for the employee while simultaneously protecting
the colony from infection.
Personnel Health Surveillance
Any occupational health and safety program should include
a personnel health surveillance component to ensure that all
personnel contacting NHPs (e.g. veterinarians, technicians,
scientists, maintenance workers, etc.) are screened for the
presence of infectious disease prior to contact with NHPs
and on a serial basis thereafter.
While health surveillance can protect a NHP colony
from a variety of diseases, perhaps most importantly among
these is tuberculosis. Mycobacterium tuberculosis (TB) can
have devastating consequences for NHP colonies and all
staff with primate contact should be screened for infection
with M. tuberculosis.
Tuberculin skin test (TST) is the standard TB diagnostic
test used to screen potential and current employees. In this
test, injection of purified protein derivative (PPD) elicits
