The San Gorgonio Mountains in Southern California are home to a population of desert bighorn sheep. At least 20 bighorn have died in the past few months. Click on the link below to learn more about what is being done to investigate the causes of the mortality event, and the important collaborative roles played by California Fish and Wildlife field biologists and veterinarians, land owners, California Animal Health and Food Safety Laboratory, and volunteers.
A big shout out and thank you to all the hunters who helped boost our CWD surveillance numbers in 2018. The results are in and have been posted on our CWD webpage. If you submitted a sample for testing, you can look up your individual results using the document number on your deer tag (e.g. D-0029999999-0).
With your help, we were able to test over 200 animals throughout the state for CWD. Fortunately, the prion was not detected in any of the samples submitted to the Wildlife Investigations Laboratory. Our job is not over though, and neither is yours. Good surveillance is the only way to continue to ensure the safety of California’s deer and elk herds. To get defensible data we need more samples from hunters like you. If you did not bring your deer or elk in for sampling this year, please consider bringing your animal in for sampling at one of our hunter check stations or CDFW Regional offices during the 2019 hunt season. The details can all be found on our webpage closer to the opening of the season.
It’s deer season, and CDFW is looking to hunters to help collect samples for our 2018 Chronic Wasting Disease (CWD) surveillance efforts. This season we are setting up CWD stations near hunt zones across the state where hunters can get their deer tested for this disease, and get their tag validated at the same time. Check out our CWD page at www.wildlife.ca.gov/CWD for a map with information about locations, dates and times of our surveillance efforts. You can also take a look at this table for the same information. We need your help to keep this devastating cervid disease out of California’s deer and elk herds. If you are planning to hunt out of state this year, make sure you are following the law, don’t bring any skull or backbone back with you! If you are hunting in a state with known CWD make sure you get your animal tested and processed in the state you harvest it, and if it tests positive give us a call (916-358-2790) we can help you dispose of it properly. Good luck.
On Thursday, August 9, 2018, the CDFW Wildlife Investigations Laboratory sampled and processed over 350 bats that had been submitted by the California Department of Public Health; all bats had been found dead throughout the State and subsequently tested negative for rabies. Assisting with the sampling and processing were representatives from the Museum of Vertebrate Zoology located in Berkeley, CA. Processing involved determining the species of each bat, collecting morphometrics, screening the bats for white-nose syndrome (WNS) under ultraviolet light, and collecting biological samples. In addition to gaining knowledge of species distribution throughout the State, the bats will provide opportunities for stable isotope research, genetic analysis, wind farm mortality studies, and growth of museum collections. Furthermore, the processing provides valuable disease surveillance data with regards to WNS, a disease that is decimating bat populations throughout the United States. For more on WNS, please visit:
The Wildlife Investigations Laboratory is working with biologists and wardens throughout California to ramp up Chronic Wasting Disease (CWD) surveillance of deer. CWD is a fatal neurologic disease of deer and elk that has been detected in 25 states, 2 Canadian provinces, South Korea, Norway, and Finland. The disease has never been detected in California, but the best defense is a robust surveillance program, and an informed public. In 2017 effort was focused on collecting samples from hunter-harvested animals in the X-zones along California’s border. In total 100 animals were tested for CWD, and all came back negative. This year CDFW plans to expand surveillance throughout the state. Keep an eye on our CWD page for more information about CWD sampling locations during the 2018 hunt season. If you are planning to hunt out of state this year, be sure to follow the law, NO SKULL or BACKBONE. We also recommend to hunters who take a deer or elk in a CWD positive state to get your animal tested and processed in that state, and not to consume the meat until you have a negative test result.
Click here to view the brochure on CWD.
Andrew Di Salvo, DVM, the inaugural Free-Ranging Wildlife Health Veterinary Resident with the CDFW Wildlife Investigations Laboratory and the UC Davis Karen C. Drayer Wildlife Health Center, shares a photo from each month of his first year…
An outbreak of bluetongue (BTV) and epizootic hemorrhagic disease viruses (EHDV) occurred in free-ranging deer in the foothills of the San Gabriel Mountains in Los Angeles County this year. The outbreak started mid to late August and continued through October. Reports from concerned citizens in the Pasadena and Altadena areas adjacent to deer habitat, including the Jet Propulsion Laboratory grounds, suggested that multiple deer were affected (> 20), deer were often found dead near streams or other water sources, there were few or no sick deer observed, and no other species were affected. The history was consistent with an outbreak of one of a group of hemorrhagic disease viruses that can affect deer. In collaboration with CDFW South Coast Region biologists and the Pasadena Humane Society, three deer associated with this mortality event were necropsied and samples were submitted to the California Animal Food and Health Safety (CAHFS) laboratory in San Bernardino. Testing at CAHFS confirmed that EHDV was the cause of death for two of the deer tested and BTV the cause of death for the third.
The Department’s Wildlife Investigations Lab (WIL) is interested in outbreaks of viral hemorrhagic diseases in California’s free-ranging deer populations. These viruses include deer adenovirus and two closely related Orbiviruses, BTV and EHDV. None of these viruses are known to affect people. Deer adenovirus was first described following a 1993 outbreak in California involving multiple counties with mortality estimates of over a thousand deer. Since first being described in California deer, deer adenovirus has subsequently been detected in association with deer mortalities in most of the Western states and may be the most important hemorrhagic disease virus affecting California’s deer. Bluetongue virus has long been recognized as a disease of both domestic ungulates like cattle, sheep, and goats, and of free-ranging ungulates like deer. Epizootic hemorrhagic disease virus is one of the most significant infectious diseases of white-tailed deer with outbreaks occurring regularly in white-tailed deer from the Northern Great Plains down to Florida, and has been associated with disease in cattle. Historically, mule deer and black-tailed deer, the deer native to California, were considered less susceptible to the Orbiviruses than white-tailed deer; however, we do see localized outbreaks of BTV and EHDV in native deer throughout California.
The Wildlife Investigations Lab would like to thank the efforts of the local citizens that reported this outbreak and the Department staff, the Pasadena Humane Society, and the California Animal Health and Food Safety labs for their efforts in determining the causes of this outbreak.
Authored by: Dr. Brandon Munk
An understanding of the demography, distribution, behavior, and genetic diversity of animal populations enables the California Department of Fish & Wildlife to properly manage species statewide. Capturing bighorn sheep provides an opportunity to place GPS and VHF collars, as well as collect biological samples (e.g. blood, nasal swabs, hair, feces). This accumulation of data will offer insight into bighorn sheep population dynamics, genetic diversity, and overall health.
From October through November of this year, CDFW participated in helicopter captures of multiple bighorn sheep populations. After ensnaring the sheep in a net, a capture crew member would exit the helicopter, secure the sheep by placing leg hobbles and an eye cover, and then either process the sheep in the field or place it in a carry bag for long-line transport to a base camp for processing. Processing at the base camp consisted of weighing the sheep, collecting morphometrics (body measurements), blood, hair, feces, and nasal swabs (for detection of Mycoplasma ovipneumoniae, a bacteria that can cause a fatal pneumonia), administering vitamin E and selenium injections, followed by GPS and/or VHF collar placement and ear tagging. Additionally, an ultrasound examination was performed to both determine body condition score by measuring the thickness of subcutaneous fat and particular muscle bodies, as well as check if any ewes were pregnant. Following processing, sheep were either released from the base camp or returned by helicopter to the capture site for release.
Up first on the schedule were the endangered Sierra Nevada bighorn sheep. Over the course of six days in the Sierra Nevada Mountains, a total of 34 sheep were captured, including seven rams, with 33 sheep receiving at least one VHF or GPS collar (33 VHF, 31 GPS). Operations then moved to the Sespe Wilderness Area within Los Padres National Forest to capture desert bighorn sheep that had originally been translocated to the area, part of their historic range, back in the mid-1980s. This was quite the unique opportunity in that these sheep were thought to be all but gone from the range in the early 2000s and were only recently seen on the landscape. Furthermore, the population hadn’t been handled in the more than 30 years since their initial reintroduction. A total of 22 sheep were captured over three days, including 10 rams, with 19 sheep receiving at least one VHF or GPS collar (15 VHF, 13 GPS). The Sespe captures were followed by four days in Anza Borrego State Park and Palm Desert, CA for field processing of desert bighorn sheep from the Peninsular Ranges. These efforts yielded 42 total captures, all ewes, with each sheep receiving at least one VHF or GPS collar (18 VHF, 26 GPS). The capture team then moved to the Mojave Desert and Death Valley National Park for seven days of desert bighorn sheep processing, yielding 71 total captures, including 18 rams, with all but two sheep receiving both a VHF and GPS collar (69 VHF, 69 GPS). Capture operations wrapped up in the White Mountains just outside of Bishop, CA, where 33 desert bighorn sheep were captured over four days, including 12 rams, with all but two sheep receiving both a VHF and GPS collar (31 VHF, 31 GPS).
In less than one month, CDFW captured 202 bighorn sheep, placed 166 VHF and 170 GPS collars, and collected abundant biological samples that will be closely studied for the next few years. The information acquired through analysis of the biological samples, as well as the continual spatial data that the collars will generate, will provide CDFW with valuable material by which they can make educated and well-informed decisions regarding the management of the state’s bighorn sheep populations.
Chronic Wasting Disease (CWD) is a fatal neurologic disease of cervids (e.g. deer, elk, moose, reindeer). It is caused by a misfolded form of a normal protein, known as a prion. The misfolded proteins aggregate in nervous tissues causing progressive damage to the brain of infected animals. CWD belongs to a group of human and animal diseases called transmissible spongiform encephalopathies (TSE). Examples of TSEs in animals include bovine spongiform encephalopathy (BSE) in cattle, also known as “mad cow disease,” and scrapie in sheep and goats, which has been known to veterinary medicine for over 200 years. Creutzfeldt-Jakob disease (CJD), a sporadic prion disease arising in 1:1,000,000 people, and variant Creutzfeldt-Jakob disease (vCJD), which has been linked to the consumption of infected cattle during the “mad cow disease” outbreak in Great Britain and Europe in the 1990s, are examples of TSEs in humans.
Since 1999, California has tested 4500 deer and elk for CWD. To date, no CWD has been found. However, the potential for CWD to spread to California’s deer and elk populations still exists and surveillance for the disease remains important.
In late September 2017, Dr. Brandon Munk (CDFW) provided information on CWD and necropsy training to CDFW biologists, USDA staff and CDFW natural resource volunteers in sampling the lymph nodes of deer. These tissue samples will be submitted to a laboratory and tested for CWD.
CDFW is asking hunters in Hunt Zone X2-X7b to voluntarily participate in this sampling and disease surveillance by bringing harvested deer to one of the CWD Sampling/Hunter Check Stations. These stations will be open during opening weekend (October 7-8, 2017).
Sampling is voluntary, easy and free. Department staff or volunteers will record the tag number and take two small lymph nodes from the neck of the deer. There will be no damage to skull or antlers, only an incision across the neck to identify and sample the lymph nodes. Hunt tags can also be validated at the same time. The entire process will only take minutes.
On Thursday, September 14, 2017, the California Animal Health & Food Safety Laboratory (CAHFS) and the California Department of Fish & Wildlife (CDFW), Wildlife Investigations Laboratory (WIL) hosted a bighorn sheep necropsy course at the CAHFS Diagnostic Laboratory in San Bernardino, California. Assisting with the course were Dr. Peregrine Wolff and wildlife technician Chris Morris from the Nevada Department of Wildlife (NDOW). In attendance were CDFW regional biologists, scientific aides, and veterinarians. The course served as an opportunity for attendees to learn how to recognize, describe, and collect samples from bighorn sheep during field necropsies. It also provided a reminder of how important it is to keep domestic sheep populations separated from free-ranging bighorn populations in order to maintain healthy herds.
After introductory remarks from Dr. Ben Gonzales (CDFW WIL), Dr. Francsisco Uzal (CAHFS) led a discussion on how to describe macroscopic lesions (i.e. distribution, size, shape, demarcation, color, consistency, contour) along with a review of the pathology of a few select domestic and bighorn sheep diseases. Dr. Francisco Carvallo (CAHFS) then expanded upon the main respiratory pathogens of bighorn sheep, which includes lungworms (Protostrongillus spp.), bacteria (e.g. leukotoxin-positive Pasteurellaceae, Mycoplasma ovipneumoniae), and viruses (e.g. respiratory syncytial virus, parainfluenza-3 virus). Following an important review of appropriate PPE (personal protective equipment) to utilize during bighorn sheep necropsies led by Meridith Rhea (CAHFS), Dr. Peregrine Wolff (NDOW) led a discussion on field necropsy techniques and nasal tumors of bighorn sheep to wrap up the morning session.
The afternoon was spent observing a bighorn sheep necropsy demonstration performed by Janet Moore (CAHFS) and Akinyi Nyaoke (CAHFS). Attendees were then given the opportunity to perform their own bighorn sheep necropsies under the guidance of the aforementioned instructors, along with assistance from Karina Fresneda (CAHFS), Patricia Gaffney (CAHFS), Dr. Francsisco Uzal (CAHFS), Dr. Francisco Carvallo (CAHFS), Dr. Peregrine Wolff (NDOW), Chris Morris (NDOW), Dr. Brandon Munk (CDFW WIL), Dr. Ben Gonzales (CDFW WIL) and Dr. Andrew Di Salvo (CDFW WIL).