Michigan Experiencing Surge in Terrestrial Rabies Cases

The Michigan Department of Community Health’s Bureau of Laboratories has detected a total of 23 cases of rabies out of 986 animals tested through June 26, 2006. These include 18 bats, four horses, and one skunk. Over the same time period in 2005, nine positive animals had been detected out of 965 submissions. Typically, July and August are the busiest months in the MDCH laboratory for rabies testing. This year is unusual not only in the number of positive animals detected in the first half of the year, but also in the fact that four horses have been found to be positive for rabies, the most in a single year since 1999 when there were three.

Both 2005 and 2006 animal rabies statistics reflect higher case numbers due to the skunk-strain of rabies. While bat rabies is detected sporadically throughout the state, the skunk-strain of rabies has, in recent years, only been detected in southeast Michigan and “the thumb” counties. In 2005, a total of 13 animals, including seven skunks, four cats, a sheep and fox were infected with this strain of rabies. For 2006, to date, four horses and one skunk have been infected with this strain. Diseases in wildlife often experience natural cycles of high and low incidence, and rabies is no exception. Rabies of terrestrial animals such as skunks are more likely to spill over into other unvaccinated domestic animals such as cats and horses as they are more likely to encounter a skunk in their natural environment, especially a sick skunk. Bat rabies rarely spills over into other species.

For most domestic species of animals including dogs, cats, ferrets, horses, cattle, and sheep, there are licensed rabies biologics available. Only dogs and ferrets are required by law to have rabies vaccinations in Michigan, but other species whose daily activities could expose them to potential rabies-infected animals should vaccinated. For up-to-date information on rabies surveillance data please visit the Emerging Diseases website at www.michigan.gov/emergingdiseases. Click on the "Rabies" topic.

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