Renewed Efforts in Chronic Wasting Disease (CWD) Surveillance

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.

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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.

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Necropsy Training: Studying disease in bighorn sheep

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Dr. Janet Moore (California Animal Health and Food Safety Laboratory – San Bernardino) instructs CDFW field staff in bighorn necropsy techniques.

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).

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Dr. Peregrine Wolff (Nevada Division of Wildlife) demonstrating locating sinus tumors in bighorn.

Scientists Battle Mange Outbreak in Urban Kit Fox Population

For the past  5 years, the WIL and it’s partners the Endangered Species Recovery Program (ESRP), UC Davis, CDFW-Region 4, USFWS, and the California Living Museum (CALM), have been working together to help San Joaquin kit foxes living in Bakersfield gain the upper hand during a fatal epidemic of sarcoptic mange. 

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Healthy male San Joaquin kit fox, #6833, in January 2017.

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The same male San Joaquin kit fox, #6833, months later in July 2017 – after becoming infested with mange.

Male San Joaquin kit fox after treatment for  sarcoptic mange.

Male San Joaquin kit fox, #6833, a month after receiving treatment for mange while at the California Living Museum, CALM. CALM is a permitted wildlife rehab facility in Kern County.

WIL environmental scientist and UC Davis graduate student, Jaime Rudd, was recently featured in a story about some of the ongoing work and it’s challenges. More about the research can be found on CDFWs Science Institute’s “Science Spotlight” website:

 Additional information about the outbreak, including a recent publication, can be found by following the link

Restoring the historic home of the Amargosa vole

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WIL staff and partners assessing the recent habitat restoration efforts. Photo credit: Austin Roy (CDFW)

WIL and our partners at USFWS, UC Davis, CDFW-Region 6, BLM, Amargosa Conservancy, and Shoshone Village are continuing to restore historic vole habitat in Shoshone, CA.  The Amargosa vole was first discovered in Shoshone in the late 1800s, but a myriad of habitat changes resulted in its local extinction from the northern part of its range.

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A recently installed interpretive sign explains the restoration project to visitors and local community members. Photo credit: Deana Clifford (CDFW)

Over the past year non-native vegetation was cleared, soil was contoured and irrigation installed in select areas to more evenly distribute water throughout the fledgling marsh.   The team’s goal was to have a light touch on the land and let the marsh do much of the work regenerating itself.

The beginnings of a marsh capable of becoming vole habitat are appearing!

This restoration project is made possible due to the dedication of local private landowners, volunteers and a community nonprofit.  The effort is funded by a Traditional Section 6 grant and a Partners for Fish and Wildlife grant through the USFWS, funds from CDFW WIL and private matching funds.  Once the marsh is fully restored, we hope to bring voles back to Shoshone and create a new population of voles which will aid in reducing the chance of this species becoming extinct.

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An example of what the marsh looked like during (a) and after (b) initial habitat restoration efforts. Photo credit: Tanya Henderson (Amargosa Conservancy) and Austin Roy (CDFW)

TWS article raises awareness about mange outbreak in Bakersfield’s endangered kit foxes

The Wildlife Society has published an article highlighting our collaborative work to understand and combat the emergence of mange in endangered San Joaquin kit foxes.

Click here to read the full article.

Click here to see our previous post about mange and kit foxes

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The signs of sarcoptic mange in wild kit foxes can be missed in the early stages. However, as the disease progresses and the mites proliferate, the devastating toll this disease has on an individual is easily apparent. Pictured is a mangy kit fox in the later stages infestation showing hair loss, thickened crusty skin, and emaciation (A). Kit foxes with severe mange cannot hunt and often succumb to starvation and hypothermia. The CALM zoo in Bakersfield is a licensed wildlife rehabilitator and has been providing the treatment and veterinary care needed to return affected foxes to good health (Photo B).

UPDATE: Restoring Habitat for the Endangered Amargosa Vole – Watching the Bulrush Grow (Pt. 2)

WIL and UC Davis just completed their one-year followup to last year’s emergency efforts to restore and rescue Marsh 1, one of the largest and most important habitat patches for the endangered Amargosa vole. That effort included reflooding the marsh, clearing out debris from dead plants, and relocating resident voles into nearby marshes during the restoration.

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Senescent plant stems, called standing litter, show evidence of last season’s growth. Photo credit: Stephanie Castle (CDFW)

In addition to checking in on the voles that were relocated during the restoration work (see our “Update Pt. 1” for more details), the team assessed the progress of Marsh 1 after the restoration. We monitored  water levels in the marsh by measuring the area of the marsh that was still flooded with standing water, as well as measuring how far below the surface the water table is in areas without standing water. Our measurements showed some great news! – water levels were just as high this year as they were last year right after the restoration.  This will help to foster a healthy crop of three-square bulrush (Schoenoplectus americanus), the plant vital to survival of the Amargosa voles.

 

Three-square bulrush is a perennial plant, its leaves die back (aka “senesce”) each winter, kind of like a deciduous tree or a lily. Because it was still so early in the growing season, we expected the bulrush hadn’t started sending up new shoots just yet. When we got out into the marsh, we actually saw a bunch of little green bulrush stems just starting to peek out of the soil. In fact, we saw twice as much bulrush this year as we have seen in previous years.

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Image of Marsh 1, 1-year post restoration. It is still early in the season and has just started popping up, but standing litter from last season’s growth shows us the extent of plant restoration. Photo credit: Stephanie Castle (CDFW).

It’s hard to tell from the pictures, but underneath all of the senesced plants from last year’s growth there were lots and lots of 4-5 inch tall stems. CDFW-WIL researchers are excited to see how much bulrush we will have in the marsh this year once the plants are in full swing (July-August). We will keep you updated this summer!

The success of this program has continued to highlight how productive partnerships between agencies, universities, non-profits, and communities can positively benefit the conservation of endangered species.

The translocations and restoration were funded by the BLM (partially through NCLS funds), and Drought Response Implementation Program (DRIP) funds from CDFW.

Prepared by: Stephanie Castle (CDFW/UC Davis)