Public Health Consequences of Banning or Restricting Trapping in Nevada Regarding Rabies
Paul Crawford, MD
Las Vegas, NV
Executive Summary
•
Rabies in terrestrial mammals is currently absent in Nevada
•
Historically, Nevada had one of the worst rabies epidemics in history
•
Aggressive control of predators by trapping and hunting stopped the rabies epidemic
•
Currently, three western states have terrestrial rabies problems—all 3 restrict
trapping by leghold traps and/or on public land. These states had 136 cases of rabies
in 2016.
•
Five western states allow trapping with liberal regulations. These five states only had
4 cases of terrestrial rabies in 2016.
Rabies is a disease that has generally faded from the national consciousness as
aggressive control programs have reduced its prevalence in much of the United States. Nevada
has only had bat rabies in wild animals (1) in the recent past due to preventive population
control of wild animals through trapping and hunting, and immunizations of domestic animals.
If preventive population control is removed as a wildlife management tool, the people of
Nevada will be placed at risk of a rabies epidemic.
Rabies is a severe zoonotic encephalitis (brain infection transmitted from animals to
humans). Early clinical signs and symptoms of rabies--including headache, fever, chills, cough or
sore throat, anorexia, nausea, vomiting, and malaise--are non-specific and easily mistaken for
more common conditions. The disease progresses rapidly (within 1-2 weeks) to central and
peripheral neurologic manifestations including altered mental status (e.g., hyperactivity and
agitation), irritation at the site where the virus was introduced, hydrophobia (foaming at the
mouth like in “Old Yeller”), excessive salivation, and difficulty swallowing due to laryngeal
spasms. Ultimately, autonomic instability (severe high blood pressure and pulse), coma, and
death occur, due mainly to cardiac or respiratory failure. There is no treatment for rabies and
reports of patients surviving are exceedingly rare. If a person is exposed to the virus, prompt
post-exposure prophylaxis (PEP) by administration of rabies immune globulin and vaccine can
prevent progression to clinical rabies.
Nevada has a long history battling rabies. (2,3) Rabies was initially introduced into
Nevada from California in the early 1900’s. It quickly reached epidemic proportions and
hundreds of Nevadans were attacked and either given the PEP for rabies or died—quite a feat
in a time when the population was only 81,875. Reports of rabid packs of coyotes attacking
towns and ranches were not uncommon. Untold numbers of livestock were infected and killed.
This led to aggressive wildlife control programs by the government and private trappers and
hunters. Dr. E.M. Records reports that by 1932, predator control resulted in stopping the
epidemic of rabies in Nevada. Eventually, through preventive population control, terrestrial
rabies was eliminated from Nevada. Preventive population reduction is much more effective
than emergency population reduction because population density is reduced and there is less
animal to animal spread of the rabies virus. (4)
Variants of rabies virus are present in certain groups of certain mammalian species
(primarily fox, skunk and bats), but all rabies viruses can infect any mammal, including livestock,
pets and humans. In Nevada, bat variant rabies viruses exist throughout the state, but
terrestrial rabies (rabies in walking mammals) is eradicated. Likewise, Utah has bat rabies, but
no terrestrial rabies. In California, Arizona, and Colorado, the skunk or fox variant is found
endemically (all the time). Arizona continues to have periodic problems with terrestrial rabies,
and, in fact, in January 2017, a rabid bobcat attacked 5 people in the resort area of Sedona. (5)
Domestic animals (dogs, cats, and livestock) can be infected with these rabies variants through
contact with rabid wildlife.
There is one primary difference between states where rabies lurks, waiting to infect
humans and livestock—the outlaw of the foothold trap for use on public land. Both Nevada and
Utah permit trapping using traditional methods while California, Arizona and Colorado ignored
public health experts and banned the foothold trap either entirely or on public land only. This
has allowed rabies to spread more easily through higher populations of wild animals. Figure 1
shows 2016 numbers of non-bat, non-domestic animal infections in the southwestern US.
Figure 1. Rabies in wildlife other than bats in Western states during 2016. Note that Nevada, Utah, Idaho,
Oregon and New Mexico allow trapping with leghold traps on public lands with liberal check times while
Colorado, Arizona and California restrict leghold traps, public land trapping, etc. (Refs 6-14)
Thus, in summary, banning the use of leghold traps, banning trapping on public land,
and allowing disturbance of private property will put the people of Nevada and their
pets/livestock at risk of rabies. Wildlife and human population expansion will enable
transmission of the disease in wildlife populations and put wildlife in contact with domestic
animals and people. I urge you to not let us go back to 1910 when people feared for their lives
due the rabies epidemic—continue to allow management of wildlife populations by trapping
state-wide with leghold traps.
References
1. Rabies found in five separate cases in Washoe County. Aug 25, 2016
https://www.washoecounty.us/outreach/2016/08/2016-08-25-rabies-health.php
Accessed Mar 28, 2017
2. Records E. Rabies-Its history in Nevada. California and Western Medicine. August 1936;
Vol. 36, No. 2:90-94.
3. Dog gives calf rabies. Sacramento Union, Number 27, 27 March 1913
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1658252/pdf/calwestmed004380019.pdf Accessed Mar 28, 2017
4. Young JA. Rabies in rangeland environments. Rangelands. April 1984; Vol 6, No. 2:51-53.
https://journals.uair.arizona.edu/index.php/rangelands/article/viewFile/11862/11135
Accessed Mar 28, 2017
5. Associated Press. Resort Arizona town on alert after rabid bobcat attacks injured 4
people. January 18, 2017. http://www.foxnews.com/us/2017/01/18/resort-arizonatown-on-alert-after-rabid-bobcat-attacks-injured-4-people.html
6. Bosworth B. Got rabies: Skunks are top carrier in Colorado. High Country News. Jul 17,
2012. http://www.hcn.org/blogs/goat/got-rabies-skunks-are-top-carrier-in-colorado
7. Arizona Game and Fish Department. Rabies in Arizona.
http://www.azgfd.gov/w_c/research_rabiesnew.shtml
8. California Department of Public Health. Reported animal rabies by county and species
2016. https://www.cdph.ca.gov/HealthInfo/discond/Documents/2016RARTable.pdf
9. Arizona Department of Health Services. Rabies cases 2016.
http://www.azdhs.gov/documents/preparedness/epidemiology-diseasecontrol/rabies/data/2016.pdf
10. Utah Department of health Rabies Report 2016.
http://health.utah.gov/epi/diseases/rabies/surveillance/2016_summary.pdf
11. New Mexico Department of Health. Animal rabies by county, New Mexico, 2016.
https://nmhealth.org/data/view/infectious/1837/
12. Colorado Department of Public Health & Environment. Rabies in Colorado. January 1,
2016-December 31, 2016.
https://drive.google.com/file/d/0B0tmPQ67k3NVdHVhYWpZbUxGNEU/view
13. Idaho Department of Health and Welfare. Rabies information.
http://healthandwelfare.idaho.gov/Health/DiseasesConditions/RabiesInformation/tabid/176/D
efault.aspx
14. Oregon Health Authority.
https://public.health.oregon.gov/DiseasesConditions/DiseasesAZ/rabies/Documents/rabiesmap
16.pdf
Dr. Crawford is a 10-year resident of Nevada. He practices and teaches Family Medicine in the US Air
Force. This voluntary testimony was prepared in his role as a private citizen using private resources and
does not reflect the official position of the US Air Force, the Department of Defense or the Federal
Government. It reflects only his concern for the people of Nevada.