![](https://webarchive.library.unt.edu/eot2008/20081028210208im_/http://cdc.gov/ncidod/eid/images/spacer.gif)
|
![](https://webarchive.library.unt.edu/eot2008/20081028210208im_/http://cdc.gov/ncidod/eid/images/spacer.gif) |
New and Emerging Zoonoses1
Marguerite Pappaioanou,*
Thomas Gomez,† and Cherie Drenzek‡
*Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †U.S.
Department of Agriculture, Riverdale, Maryland, USA; and ‡Georgia Department
of Human Resources, Atlanta, Georgia, USA
Suggested
citation for this article
Seventy-five percent of emerging infectious diseases are transmitted
from animals to humans. The panel focused on different factors that have
caused transmission from animals to humans for four diseases in recent
years. The monkeypox infections in humans in the United States in 2003
were the first introduction of the disease into a human population outside
Africa. This outbreak resulted from expanded global commerce and travel
involving exotic rodents. Humans were infected through contact with ill
pet prairie dogs, which had been housed with exotic rodents imported from
Africa in April 2003. Laboratory evidence suggested that multiple species
of imported rodents were infected, including rope squirrels, Gambian rats,
and dormice. Through testing by classic laboratory methods and newer nucleic
acid, real-time polymerase chain reaction methods, ultimately 37 human
cases were identified. The disease in U.S. patients differed from that
previously described in human outbreaks in Zaire/Democratic Republic of
Congo. The Centers for Disease Control and Prevention and the U.S. Food
and Drug Administration enacted a ban on importation of African rodents
and distribution of prairie dogs in the United States to prevent additional
introduction of infected animals. Zoonotic concerns remain, including
whether monkeypox was transmitted to other North American mammals that
may have come into contact with the imported infected rodents. Ongoing
studies are focusing on the pathogenesis of infection, incubation period,
length of transmissibility, and expression of disease in rodents—all which
remain poorly understood.
Several human and animal Ebola virus outbreaks have occurred in West
and Central Africa since 2001, causing 313 human cases and 264 deaths.
These outbreaks have consisted of multiple simultaneous epidemics caused
by different viral strains, with each epidemic resulting from humans'
handling of distinct gorilla, chimpanzee, or duiker carcasses. Wildlife
die-offs coincided in time and space with human Ebola outbreaks. Based
on these results, Ebola virus was proposed as the cause of the rapid local
collapse of these wild animal populations. Carcasses were infected by
a variety of Ebola virus strains, which suggests that Ebola outbreaks
in great apes resulted from multiple virus introductions from an unidentified
natural reservoir host. It was proposed that outbreaks in humans could
possibly be prevented or predicted by monitoring animal deaths.
The California sea otter, a subspecies named on federal lists of threatened
species, is found only along the central coast of California. More than
40% of California sea otter deaths are attributed to infectious agents,
including some more typically associated with terrestrial animal and human
disease, such as Toxoplasma gondii. Brain infection with T.
gondii has been documented to cause significant numbers of sea otter
deaths in California. Growing evidence supports a land-sea connection
associated with contamination of the coastal environment, and the source
of infection to sea otters.
Domesticated cats, the terrestrial definitive hosts of T. gondii,
recently have been found to inhabit the coastal California landscape.
From 1997 to 2001, T. gondii seroprevalence was 42% (49/116), in
live sea otters and 62% (66/107) in dead otters. Risk factors positively
associated with T. gondii seropositivity included male gender;
older age; presence in Morro Bay, California; and freshwater outflow exposure.
These findings illustrate pathogen pollution in the marine ecosystem and
suggest that sea otters could be an indicator species for as-yet-unrecognized
human health risks.
An outbreak of highly pathogenic avian influenza A virus subtype H7N7
occurred in the Netherlands beginning in February 2003. The Netherlands
Ministry of Agriculture instituted an eradication program to control H7N7
avian influenza in poultry (30 million chickens culled; 255 farms; 20%
symptomatic). An unexpectedly high number of H7N7 transmissions occurred
in persons directly involved in handling infected poultry; evidence for
person-to-person transmission was documented. Enhanced surveillance showed
that 453 of an estimated 4,500 people thought to be exposed reported health
complaints—349 reported conjunctivitis, and 67 reported other complaints.
One veterinarian died. After 19 cases had been identified, all workers
received mandatory influenza virus vaccination and prophylactic treatment
with oseltamivir. Fifty-six percent of reported H7N7 infections arose
before the vaccination and treatment program. By the time full prophylactic
measures were reinforced (1 week after the first confirmation of human
infection), >1,000 persons from all over the Netherlands and from abroad
had been exposed. Poor compliance was observed in the use of personal
protective equipment among poultry farmers and cullers.
1Presented at the International Conference
on Emerging Infectious Diseases, Atlanta, Georgia, February 29
March 3, 2004, by Inger Damon, Centers for Disease Control and Prevention;
Eric Leroy, Centre International de Recherches Medicales de Franceville,
Gabon, Africa; Melissa Miller, University of California Davis Wildlife
Health Center; and Marion Koopmans, National Institute of Public Health
and the Environment
Suggested citation
for this article:
Pappaioanou M, Gomez
T, Drenszek C. New and emerging zoonoses. Emerg Infect Dis [serial on
the Internet]. 2004 Nov [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol10no11/04-0797_05.htm
|