July 16, 2003
Awareness Best Way To Guard Against Wildlife-Related Diseases
LINCOLN, Neb. — Monkeypox, West Nile virus, tularemia, rabies and hantavirus have more in common than being highlighted in recent news reports, University of Nebraska specialists said.
They also happen to be diseases that occur in both animals and people, said Dallas Virchow, coordinator of wildlife damage control in NU's Institute of Agriculture and Natural Resources. Such diseases are commonly called zoonoses.
"Of the 1,709 infectious organisms known to cause diseases in humans, nearly half are zoonotic," Virchow said. "Extra care should be taken to guard against them, especially in years of high incidence."
Some diseases, such as rabies, are typically cyclic, with incidences being extremely low during some periods and increasing during others. For example, from 1992 to 2002, fewer than five skunks tested positive for rabies each year in Nebraska. However, rabies among skunks now is at a 20-year high with 57 skunks testing positive so far this year, said Scott Hygnstrom, NU Cooperative Extension wildlife damage specialist.
Other zoonotic diseases, such as West Nile virus, which is new to Nebraska, may result in more animal fatalities during the first several years after it shows up. Later generations tend to develop resistance to the disease over time, he said.
While certain factors, such as geography, occupation, age, health status and level of outdoor activity, may predispose some people to come in contact with a zoonotic disease, most people are safe, Virchow said.
"Chances of exposure may be slim to none, unless you are among the few people within high risk groups that work directly with animals," he said.
Common modes of disease transmission include contact with animal body fluids, consumption of infected meat or indirect contact with contaminated air, water or soil. Infectious organisms of many zoonoses are carried from animals to people by insects or ticks. Therefore, avoiding insect bites and insect-infested areas can reduce risk, Virchow said.
People can reduce their exposure to zoonoses by making sure pets are vaccinated, keeping pets inside from dusk through early morning, keeping pets away from wildlife and wearing plastic gloves when handling dead animals, Hygnstrom said.
Fortunately, most zoonotic diseases are not life-threatening, he said. However people should be aware of the diseases' early and late symptoms, seriousness and treatment.
"Despite deaths due to West Nile and hantavirus, symptoms produced by almost all zoonoses in people can be either mild or effectively treated when diagnosed early," he said.
In addition, frequent headlines about zoonotic diseases may cause more fear than necessary, Virchow said. Statistics show that the risk of infection from life-threatening zoonoses is very low compared to other diseases.
Hantavirus cases in the United States average about 10 per year. Monkeypox, though new, has 71 cases to date.
About 100 deaths and 4,000 to 9,000 hospitalizations due to chicken pox occurred each year in the United States before an effective vaccine was used in 1995, he said. Furthermore, monkeypox seems to have a low rate of infection via person-to-person contact. Chicken pox, a common childhood disease, remains highly contagious among humans, he said.
"The number of deaths attributable to zoonoses are lower than those caused by other common diseases," he said. "For instance, more than 200 Omahans died during the first half of 2003 from influenza or pneumonia. By contrast, rabies deaths across the entire U.S. average less than one each year."
For more information about zoonotic diseases, consult these Web sites: The Centers for Disease Control, Nebraska Health and Human Services, NU's Cooperative Extension Internet Center for Wildlife Damage Management, National Institute of Allergy and Infectious Diseases, and the American Veterinary Medical Association.
7/16/03-RS Dallas R. Virchow
School of Natural Resource Sciences Extension Assistant Wildlife Damage Control (402)472-8961
 
Scott Hygnstrom - Ph.D.
School of Natural Resource Sciences
Associate Professor
(402) 472-6822
Sandi Alswager Karstens
IANR News and Photography
(402) 472-3030
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