Bubonic plague outbreak amongst Black-footed ferrets and prairie dogs in South Dakota
Black-footed ferret. USFWS.
Black-footed ferrets, back from extinction
By the late 1970s the black-footed ferret was thought to be extinct. However in 1981 a dog belonging to farmers in Wyoming killed a black-footed ferret, and a few months later a live black-footed ferret is spotted. A small breeding population is discovered, containing just 129 animals, and plans are made to begin a captive breeding program.
However in 1985 outbreaks of sylvatic plague and canine distemper decimate the population of the ferrets, so the last 18 known animals are brought into captivity in an effort to save the species.
Amazingly, more than 5,100 kits have been born in captivity since 1987, and since 1991, more than 2,200 have been reintroduced to the wild in the black-footed ferrets' historical range in Arizona, Colorado, Montana, South Dakota, Utah, Wyoming, and northern Chihuahua, Mexico.
August 2008. In May, sylvatic plague was confirmed in prairie dog colonies in the Conata Basin Area of South Dakota. More than 4,000 acres of prairie dog colonies have been affected to date, including some areas occupied by black-footed ferrets.
Halting the spread of the plague
One of the strategies involves using insecticides to reduce flea populations in prairie dog colonies that have high value to black-footed ferrets but have not yet experienced plague die offs.
Other strategies still being investigated, involve use of insecticides in portions of the plague impacted area and vaccination of black-footed ferrets in certain areas. An insecticide application in the impacted area would be intended to reduce flea numbers that could otherwise attach to animals and be moved to other areas. A flea reduction effort should lower chances of fleas getting on pets or people. Vaccines may be used in an attempt to protect ferrets in certain areas where ferrets can be readily located.
First detected in 2004
The South Dakota Department of Health noted that since plague was first identified in South Dakota in 2004 in wildlife, there have not been any cases confirmed in humans. However, Lon Kightlinger with the Department encouraged continued precautions when working in the area and avoidance of handling sick or dead animals. While this is a good rule to follow in general, it is particularly applicable in the area experiencing prairie dog die offs. Additionally, pets should not be allowed to roam in the affected prairie dog colonies in order to avoid flea accumulation on pets.
Plague may enter a person through a break in the skin by direct contact with tissue or body fluids of a plague-infected animal. Plague can also be transmitted by inhaling infected droplets expelled by coughing by a person or animal, especially domestic cats, with pneumonic plague.
More information can be obtained by contacting the Center for Disease Control's Division of Vector Borne Infectious Diseases website, http://www.cdc.gov/ncidod/dvbid/plague/index.htm .
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