Tag Archives: Disease

CDFW Investigating Die-Off of Desert Bighorn Sheep

Wildlife biologists from the California Department of Fish and Wildlife (CDFW) are investigating what appears to be a significant mortality event associated with respiratory disease among the San Gorgonio desert bighorn sheep population in Riverside County. CDFW has confirmed that at least 20 animals have died but suspects that total mortality may be greater.

“The significance of this outbreak to the San Gorgonio desert bighorn sheep population is being investigated,” explained Heidi Calvert, an environmental program manager with CDFW’s Inland Deserts Region. “Our top priority right now is to determine the source and nature of the disease so that we can identify the right management actions to mitigate future risk.”

CDFW staff began receiving reports of sick desert bighorn sheep in December 2018 and immediately began collecting samples for lab analysis. CDFW is continuing to survey and monitor the population to gather more information on the extent and magnitude of this loss to the population. Private landowners and partner agencies are assisting with this effort.

The Western Association of Fish and Wildlife Agencies Wild Sheep Working Group considers respiratory disease to be “the biggest impediment to restoring and sustaining bighorn sheep populations.” Respiratory disease in bighorn sheep is most commonly attributed to contact and/or proximity with domestic sheep and, to a lesser extent, domestic goats. Diseases that originate with domestic animals can pose a significant risk to bighorn sheep populations.

The affected desert bighorn population is located within Desert Bighorn Sheep Hunt Zone 5. The recent die-off will likely result in reducing the two hunting tags to zero in this zone for 2019.


Media Contacts:
Heidi Calvert, CDFW Inland Deserts Region, (760) 872-0751 

Kirsten Macintyre, CDFW Communications, (916) 322-8988

DFG Continues Investigation of Western Grey Squirrel Deaths

 Media Contacts:
Jeff  Villepique, DFG Wildlife Biologist, 760-937-5966
Janice Mackey, DFG Communications, 916-322-8908

Residents of
San Bernardino Mountains Asked to Help Collect Information

Last spring, the California Department of Fish and Game (DFG) received reports from residents of sick and dying western gray squirrels in Big Bear Valley. 

Researchers from DFG, the California Animal Health and Food Safety Lab in

Western Grey Squirrel

San Bernardino, and University of California, Davis, School of Veterinary Medicine concluded the squirrels were dying from complications of mange, a contagious skin disease caused by parasitic mites that burrow into the skin of affected animals, causing intense itching and infection. 

Surveys conducted in spring of 2012 yielded only a handful of western gray squirrels in areas of the Big  BearValley where squirrels were once plentiful.

Local residents are now being asked to help collect data so researchers can better understand past abundance, where sick squirrels have been observed, and where western gray squirrels are now. The website address to report information is at: https://sites.google.com/a/ucdavis.edu/san-bernardino-squirrels

Information provided by the public will help construct a picture of what happened to the squirrel population in the San Bernardino Mountains and help track the pace of their re-growth. In addition, this information will also help researchers determine whether conservation measures can be taken to prevent further loses of squirrels.

The species of mange mites affecting gray squirrels, Notoedres centrifera, is specific to rodents and cannot infect humans or pet cats and dogs. Veterinary researchers caution residents that local wildlife, including coyotes, raccoons and bobcats often carry other species of mange that can infect their pets and, rarely, people. If your pet scratches excessively or develops scabs, you should seek veterinary care as symptoms could be from one of the other forms of mange, which are readily treatable.

DFG Investigates First Cases of Canine Distemper in Wild Desert Kit Foxes

Desert kit fox
Desert kit fox with radio collar

Andrew Hughan, DFG Communications, (916) 322-8944
Deana Clifford, DFG Wildlife Veterinarian, (916) 358-2378
Erin Curtis, Bureau of Land Management, (916) 978-4622

The Department of Fish and Game (DFG) is investigating the death of seven desert kit foxes from canine distemper in eastern Riverside County. These deaths, which occurred over the past two months, are the first documented cases of canine distemper in wild desert kit foxes. Wildlife officials want to determine if this is an isolated case or if the disease is more widespread.

The kit foxes were found 20 miles outside of Blythe on public lands managed by the Bureau of Land Management (BLM) and leased to Genesis Solar LLC to construct a utility-scale solar project. The animals were turned over to DFG’s wildlife investigations lab for testing. The necropsies determined that distemper was the cause of death, but it is not known how the foxes contracted the disease. Canine distemper can cycle naturally in wild carnivore populations, but can also be transmitted to and from domestic animals that come in contact with wildlife.

“Although we do not know if this outbreak was started by an infected domestic animal, it is important for people to vaccinate their pets regularly,” said DFG Wildlife Veterinarian Deana Clifford. “Vaccination will not only protect your pet but help protect wildlife populations from disease outbreaks.”

To better understand the extent of the disease, how it was contracted and how to prevent it, wildlife officials trapped, tested and tagged 39 foxes. Researchers also attached radio collars to 12 of these foxes in order to obtain health information for the study. These collars are equipped with a mortality signal that pulses twice as fast as normal if the animal has not moved for six hours. This allows researchers to detect a death and quickly recover the carcass. Biologist and volunteers will be using the radio signals and remote triggered cameras to monitor dens during the upcoming pupping season.

In addition, a subset of 27 kit foxes received a distemper vaccine and were released back into the wild. Researchers hope this vaccine, specifically developed for use in species that are very sensitive to the virus, will create an immune response in the desert kit fox population.

The desert kit fox, found in the southeastern deserts of California, can survive in dry climates because it obtains all its water from food sources. Its more northern relative, the San Joaquin kit fox, is listed as endangered under both state and federal endangered species acts due to loss of habitat and other factors.

“Even though the desert kit fox is not endangered, it is a uniquely adapted species that deserves monitoring and conservation attention,” said DFG Environmental Scientist Magdelena Rodriguez. “We are building strong relationships with our partner agencies and other stakeholders working in the desert to better conserve kit fox populations.”

DFG is coordinating its efforts with the California Energy Commission, who is the state permitter for the solar project, and the U.S. Bureau of Land Management. Construction in the area has been temporarily halted, in part due to the kit fox distemper discovery.

“We are working closely with the company in an effort to avoid additional impacts to desert kit foxes in areas where construction is under way,” said BLM’s Palm Springs Field Manager John Kalish.

DFG Investigates Decline in San Bernardino Mountains Squirrel Population

Media Contacts:
Jeff Villepique, DFG Region 6, (760) 937-5966
Andrew Hughan, DFG Communications, (916) 322-8944

Recently San Bernardino mountain area residents have seen fewer western gray squirrels and reported sick and dying animals to the Department of Fish and Game (DFG). Researchers have determined that tree squirrels are becoming sick and dying from mange, a skin disease caused by mites.

The species of mange mites affecting gray squirrels has been preliminarily identified as Notoedres centrifera, which is specific to rodents and cannot infect humans or pet cats and dogs. Veterinary researchers caution residents that local wildlife, including coyotes, raccoons and bobcats often carry other species of mange that can infect their pets and, rarely, people.Photograph of a squirrel.

While the reason for the squirrel mange outbreak is not known, DFG Wildlife Biologist Jeff Villepique explained that a high population density of squirrels and aggregation at feeders makes the spread of any disease far more likely.

“Gray squirrels were at higher numbers than natural foods would support, because artificial feeding is prevalent in the mountain communities,” said Villepique. “The inevitable consequence when you combine an artificially high population with animals gathering at food sources is the eventual spread of disease.”

Photograph of a squirrel with mange.DFG biologists have been closely working with the California Animal Health and Food Safety Lab in San Bernardino, and UC Davis veterinary researchers to find the cause of the die off.

Thorough examinations of a number of squirrels from the Big Bear Valley have shown only illness that can be explained by the mange mites. Although West Nile virus (WNV) has been detected in squirrels in the mountain communities in recent years, no squirrels have tested positive for WNV so far this year.

California’s WNV monitoring program is continuing to cooperate with UC Davis researchers to share information.

If your pet scratches excessively or develops scabs, you should seek veterinary care, as symptoms could be indicative of one of the other forms of mange, which are readily treatable in pets. Please do not feed squirrels because of the potential for spreading disease.

Residents are asked to report a dead bird or squirrel by calling (877) 968-2473 (877-WNV-BIRD) or submitting an online report at www.westnile.ca.gov/report_wnv.php.