Biomedical Engineering Reference
In-Depth Information
and mortality seen in imported animals in the last 20
years. There has been far less use of wild-caught animals,
and the variety of species used in biomedical research has
decreased, with emphasis on baboons, macaques, African
green monkeys, squirrel monkeys, and marmosets. This,
coupled with improved diagnostic techniques used in
screening quarantine animals and established colonies,
helps identify carrier animals (
Scheftel et al., 2010
).
When there is suspicion that a zoonotic agent is present,
CDC should be contacted immediately for guidance and
assistance in diagnosis, establishment of quarantine
containment and personnel protective measures, and
disposition of infected animals and decontamination of
facilities.
(
Hull, 1969b
). There has been one other incident of Mar-
burg virus infection, with three cases reported in Africa
(
Gear et al., 1975
).
Subsequent studies in African green, squirrel (Saimiri
sciureus), and rhesus (Macaca mulatta) monkeys showed
that experimentally induced Marburg virus infection was
fatal to all. Circulating blood levels were
10
10
virus
particles/ml, and viruses were excreted in the saliva,
urine, and feces of these animals (
Haas and Maass, 1971
).
These findings, and the fact that other studies showed no
evidence of a complement-fixing antibody to the Marburg
virus in feral animals (
Slenczka et al., 1971
), indicate that
it is not a simian agent and suggest that direct contact and
aerosols are the mechanisms for transmission between
animals (
Haas and Maass, 1971
). Recent studies have
documented the differences between Marburg and other
filoviruses, but many aspects of the virus, including
reservoirs and modes of transmission in the wild, are
still not known (
Ascenzi et al., 2008; Hartman, et al.,
2010
).
The hemorrhagic syndrome just described is seen in
both human and nonhuman primates. Respiratory expo-
sures to infectious aerosols, mucous membrane exposure to
infectious droplets, and accidental parenteral inoculation
are the primary hazards to laboratory or animal care
personnel (
Center for Disease Control/National Institutes
of Health, 2009
).
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VIRAL DISEASES
Even the most species-specific human viruses are trans-
missible to one or more nonhuman primate species, so the
potential of all viruses found in these animals to be passed
to people cannot be ignored. The viruses presented in this
section are associated with human infection, have high
potential for transmission to people working with naturally
or experimentally infected animals, or have grave conse-
quences of infection.
Hemorrhagic Fevers
The hemorrhagic fever syndrome characterized by high
fever, epistaxis, ecchymoses, bleeding of the gastrointes-
tinal tract and other organs, hypotension, and shock is
caused by many viruses. Human infection with a number of
these agents has been associated with nonhuman primates.
Prevention
Biosafety Level 4 practices, containment
equipment, and facilities are recommended for all activities
using materials of human or animal origin that may be
infected with the Marburg virus. These materials include
blood, urine, respiratory and throat secretions, semen, and
tissues. The historic “Marburg incident” increased aware-
ness of the zoonotic potential of nonhuman primates and
was responsible, in part, for many of the practices that are
now standard procedures. Observation and documentation
of the various types of exposure that resulted in the trans-
mission of the Marburg virus from animals to research
workers demonstrated the need for primary protective
barriers, such as gloves and long sleeves.
The epidemiological evidence for initial infection of the
monkeys via transmission from other species of exotic
animals is a prime example of the need for strict separation
of species.
Marburg Virus Infection
The Marburg virus was first discovered in 1967, when it
caused death in seven of 31 human cases in simultaneous
outbreaks in Germany and Yugoslavia. This disease is also
known as “vervet or green monkey disease” because the
entire epidemic was traced to a single shipment of African
green monkeys (Cercopithecus aethiops) that traveled from
Uganda to Frankfurt and Belgrade via London, where they
were kept with other exotic species in the airport animal-
holding area. Although data concerning the epidemiolog-
ical interrelationships of this outbreak were incomplete, it
is noteworthy that the primary human cases were among
those individuals who worked with tissue and blood from
the animals or human patients; none were among the
animal handlers. Eleven primary cases were related to
monkey sacrifice or necropsy, five to cleaning contami-
nated equipment, and five to surgical manipulation of the
animals. One secondary case, the wife of a primary patient,
was thought to have been caused by sexual transmission
because the virus was demonstrated in the man's semen
Ebola and Other Filovirus Infections
In 1976, outbreaks of severe hemorrhagic fever occurred in
Zaire and in the Sudan. A third outbreak occurred in the
Sudan in 1979. Avirus, named Ebola after a local river, was
isolated from patients in both countries. The Ebola virus is
related to the Marburg virus and both were later classified in
a new virus family, Filoviridae, with one genus, Filovirus.
