A high sierra environment, Washoe County benefits from a variety of flora including pine trees
A high sierra environment, Washoe County benefits from a variety of flora including pine trees

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Rabies

The Vector-Borne Disease Prevention Program (VBDPP) staff will pick up wild rabies-susceptible mammals to which humans or domestic animals may have been exposed that are reported to our office. Our staff transports these animals to the Nevada State Department of Agriculture Animal Diseases Laboratory (ADL) for rabies testing. If the results of this testing show that the animal was infected with rabies, humans or domestic animals who might have been exposed to it may need shots to protect them from the disease. In the case of a domestic animal, a quarantine period requiring close observation is necessary.

The VBDPP often uses the testing of wild animals to determine the prevalence of certain diseases such as rabies that are of concern to humans. Surveillance for these diseases that exist in nature can be done several ways. The method known as "active surveillance" involves the live trapping of animals in a given area and testing them for a disease. Unfortunately the costs and time involved make active surveillance for rabies a prohibitive venture. The method used with rabies of selecting only those mammals that are found to be sickly or dead for testing is known as "passive surveillance"; it does not tell us what percentages of bats or other wild animals living in our area are infected with the rabies virus.

The table and graph below shows the test results of passive surveillance for rabies for the years 1992 - 2005. The data confirms that the rabies virus has a continuing and viable presence in wild animal species, primarily bats, living in the area. This type of survey also tells us when a new species, such as the gray foxes that tested positive for rabies in 2002, become infected. This was the first time in twenty-five years that any animal other than bats had been reported rabies positive in Washoe County. This information underscores the importance of vaccinating dogs, cats, and ferrets against rabies as required by State law (NAC 441A.435). The State Veterinarian also recommends that horses in Washoe County be vaccinated against rabies.

Rabies Positives - 2005
Date Species Location
June 17 Little Brown bat Sparks
July 5 Little Brown bat Pyramid Lake
July 14 Mexican Free-tail bat Reno
August 5 Mexican Free-tail bat Sparks
August 11 Little Brown bat Reno
August 17 Big Brown bat Reno
August 24 Mexican Free-tail Reno
August 26 Little Brown bat Flanigan

Number of rabies positive specimens in Washoe County - 1992: 8 1993: 5 1994: 1 1995: 5 1996: 3 1997: 5 1998: 0 1999: 3 2000: 3 2001: 1 2002: 10 2003: 5 2004: 3

All the specimens represented in the bar graph were various species of bats with the exception of two gray foxes that tested positive for rabies in 2002. The Centers for Disease Control and Prevention in Atlanta completed the confirmatory testing on the foxes and determined that the infective rabies virus was a bat variant. Through genetic testing of the virus, it was determined that a bat had first bitten and infected a third fox that subsequently bit the two infected foxes that were trapped by the VBDPP staff and tested. The intermediate fox was never found.