Category: Disease, Parasites & Virus

CWD in South-Central Texas

It’s official, chronic wasting disease (CWD) has been found in a white-tailed deer in Medina County, Texas, which is located just West of San Antonio. An epidemiological investigation to determine the extent of the disease, assess risks to Texas’ free ranging deer and protect the captive deer and elk breeding industry is underway.

The effort is being led by the Texas Animal Health Commission (TAHC), in coordination with the Texas Parks and Wildlife Department (TPWD) and U.S. Department of Agriculture’s Animal and Plant Health Inspection Service Veterinary Services (USDA/APHIS/VS).

CWD: Bad News for Medina County, Hill Country

Based on what we’ve all seen and read about CWD, deer hunters know this is not good news. The single bright spot is that the deer that tested positive for CWD was a free-ranging animal. The two-year-old white-tailed deer that was confirmed positive for CWD in Medina County is located within a deer breeding facility.

This is the first case of CWD detected in captive white-tailed deer in Texas. CWD was first found in Texas in 2012 in free-ranging mule deer in the Hueco Mountains in far West Texas.

Captive Deer Tested Positive

The Medina County tissue samples submitted by the breeder facility in early June as part of routine deer mortality surveillance revealed the presence of CWD during testing at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in College Station. The National Veterinary Services Laboratory in Ames, Iowa, confirmed the findings on Tuesday, June 30.

Officials have taken immediate action to secure all cervids at the Medina County breeder facility with plans to conduct additional investigation for CWD. In addition, those breeder facilities that have received deer from the Medina County facility or shipped deer to that facility during the last two years are under movement restrictions and cannot move or release cervids at this time.

TPWD is disallowing liberation of captive deer from all breeder facilities into the wild at this time pending further review. Additional measures to further minimize risk of CWD spreading into Texas’ free-ranging white-tailed deer herd, and to protect the captive deer breeding industry, will be considered.

“This is a terribly unfortunate development that we are committed to addressing as proactively, comprehensively, and expeditiously as possible. The health of our state’s wild and captive deer herds, as well as affiliated hunting, wildlife, and rural based economies, are vitally important to Texas hunters, communities, and landowners. As such, our primary objectives are to determine the source of the disease and to identify other deer breeding facilities and release sites that may have received deer from affected facilities,” said Carter Smith, TPWD Executive Director. “Working collaboratively with experts in the field we have developed protocols to address CWD, and our implementation efforts are already well under way.”

CWD Response

TPWD and the TAHC CWD Management Plan will guide the State’s response to this incident. The plan was developed by the State’s CWD Task Force, which is comprised of deer and elk breeders, wildlife biologists, veterinarians and other animal-health experts from TPWD, TAHC, TVMDL, Department of State Health Services, Texas A&M College of Veterinary Medicine, and USDA.

Since 2002, the state has conducted CWD surveillance throughout Texas for the disease. More than 34,000 samples collected from hunter-harvested and road kill deer have been tested for CWD.

Watch: Medina County, Breeder Deer

Although animal health and wildlife officials cannot say how long or to what extent the disease has been present in the Medina County deer breeding facility, the breeder has had an active CWD surveillance program since 2006 with no positives detected until now.

“We are working with experts at the local, state and federal level, to determine the extent of this disease, and respond appropriately to limit further transmission,” said Dr. Andy Schwartz, TAHC Epidemiologist and Assistant Executive Director. “Strong public awareness and the continued support of the cervid industry is paramount to the success of controlling CWD in Texas.”

Deer and Toxoplasmosis

Hunters are often concerned about feral hogs impacting a local deer herd, but feral cats? Well, it turns out that free-ranging house cats are doing more out in the woods than just killing mice and raiding songbird nests. Feral cats are also spreading parasites to white-tailed deer, other animals and maybe even to you.

The problem is toxoplasmosis, a parasitic disease caused by the protozoan Toxoplasma gondii. Will cats infected with the parasite impact deer hunting in your area? Probably not, for a number of different reasons, but it’s important to pay attention if you eat venison since this disease is prevalent in many areas.

It’s currently estimated that more than 60 million people in the U.S. have the Toxoplasma parasite in them. Most people will not get sick, though the parasite can cause serious problems for some others, such as those with weakened immune systems and babies whose mothers become infected for the first time during pregnancy.

Problems stemming from an infection can include damage to the brain, eyes, and other organs; serious stuff. For those at risk of complications, every precaution should be taken.

Toxoplasmosis in Deer Meat

Source: “This study documents the widespread infection of deer populations in northeastern Ohio, most likely resulting from feral cats, and highlights the need for consumers of venison to make absolutely certain that any deer meat planned for consumption is thoroughly and properly cooked,” said Gregory Ballash of the Department of Veterinary Preventive Medicine at Ohio State University and lead author of the study.

Two hundred free-roaming cats and 444 white-tailed deer were tested for the parasite Toxoplasma gondii, which causes toxoplasmosis. Almost 60 percent (261) of the deer showed evidence of infection and more than 65 percent (164) of the studied cats tested positive.

According to the report, approximately 14 percent of the United States’ human population is infected with toxoplasmosis by the age of 40, with an estimated 1 million new cases diagnosed each year.

Cats, both domestic and wild (such as bobcats), play a critical role in the spread of toxoplasmosis because they serve as the definitive hosts, fulfilling the requirements needed for the parasite to sexually reproduce and complete its life cycle.

Toxoplasmosis: A Widespread Disease

This parasitic disease is not just limited to deer in Ohio. Similar estimates for white-tailed deer infections have been found in Iowa (53.5 -64.2 percent), Pennsylvania (60 percent), and Mississippi (46.5 percent), suggesting Toxoplasma gondii is thriving entirely because of feral cats.

The domestic cat (Felis catus) is not native to North America, but free-ranging feral populations are often abundant at the fringes of urban/suburban areas, where deer are found and hunting takes place.

The odds of deer from urban locations testing positive for toxoplasmosis were nearly three times those of deer from more rural areas. The study found that densities of human households, and likely cats, were a significant predictor of infection in deer.

Since the parasite that causes this disease has the ability to impact a fetus during gestation, there is potential for this protozoan to impact a deer population on a local level.

If you hunt suburban properties or in places with high numbers of feral cats, consider cooking that steak well done next time you fire up the grill to knock out any toxoplasmosis in your deer meat. Otherwise, the Center for Disease Control says you can freeze venison for several days at sub-zero (0° F) temperatures before cooking to greatly reduce the risk of a toxoplasmosis infection.

Bullwinkle Disease in Deer

The term “Bullwinkle disease” sounds more like a joke about someone than an actual ailment. As it turns out, Bullwinkle disease in deer is a thing. It’s a true-to-life disease that can impact deer. Although quite rare, it seems white-tailed deer can get an infection that causes their muzzle to swell. In turn, their face looks more like the cartoon moose Bullwinkle than that of a normal, healthy whitetail.

Wildlife vets know that the head swelling is caused by a long-term bacterial infection in soft tissues of the afflicted deer’s face. However, the most fascinating part of Bullwinkle disease is that no one knows how deer get it. Or even where the bacteria comes from.

Bullwinkle Deer

Source: “The Southeastern Cooperative Wildlife Disease Study (SCWDS) has been studying the parasites and diseases of white-tailed deer for more than 56 years. With so much time and effort invested in this area, one would think that few surprises would be left, but that doesn’t ever seem to be the case. Since 2005, we have received samples from ten deer with oddly deformed muzzles, as well as reports of several other affected deer. The swollen muzzles give them a strange appearance and prompted someone to call them “Bullwinkle deer,” based on their resemblance to the 1960’s cartoon character.

Although the cases reported to us are uncommon, they occur over a wide geographic area. In fact, affected white-tailed deer have been submitted to SCWDS from as far north as Michigan and as far south as Alabama. Furthermore, the condition also has been confirmed in a mule deer buck in Idaho.

Bullwinkle Disease in Deer & Head Swelling

The swollen faces are the result of chronic inflammation in the soft tissues of the muzzle. Deer with lumpy jaw can also have swollen jaws, but not to the same extent. The inflammation also is seen in connective tissues in the oral cavity, but it is much more severe on the nose and upper lip. All of the deer examined have had similar colonies of bacteria within the inflammatory infiltrates. Attempts to culture the bacteria have been frustrating. This is possibly due to chronicity of lesions, freezing and storage of samples prior to submission. Alternatively, it may be due to excessive growth of secondary bacterial contaminants.

Staining characteristics and DNA sequencing of the bacterial colonies observed suggest they differ from other organisms known to cause problems in deer. Investigations continue into the bacteria’s potential role in the development of this condition.

So far, all of the reported cases have been in hunter-killed deer or deer observed in the wild. Some deer have been thin, but there have been no reports of mortality directly attributed to this disease. One landowner reported having seen the same affected deer at a backyard feeder for nearly two years. Many of the deer observed or killed have been known to visit feed sites. However, the association with feeding is anecdotal. At this time, we do not know the factors that may predispose a deer to develop this unusual condition.

The lesions are certainly dramatic, but this disease does not appear to have any negative consequences for deer populations. Cases are relatively infrequent and are not clustered. It is possible that this problem has always occurred in deer, but at a very low prevalence. However, it has become very easy for photographs to be widely circulated among hunters and biologists in a very short period of time. We can attribute that to hunters, trail cameras and the internet.

This rapid sharing of information may have increased the detection and submission of rare and unusual cases, such as the Bullwinkle disease in deer we see here. Prepared by Kevin Keel, University of California-Davis”

It seemed like just a matter of time before Chronic Wasting Disease (CWD) was found in Texas, but today it was verified: Texas deer have the highly contagious deer disease, or at least a couple of deer did. Samples from two mule deer recently taken in far West Texas have been confirmed positive for CWD.

These are the first cases of CWD detected in any deer species found in Texas. Wildlife officials believe the event is currently isolated in a remote part of the state near the New Mexico border. The idea is to now limit transmission of the disease within the state, insulating deer populations, deer hunting and the deer breeding industry across the rest of Texas.

Source: “The Texas Parks and Wildlife Department (TPWD) and the Texas Animal Health Commission (TAHC) implemented regionally-focused deer sample collection efforts after the disease was detected in the Hueco Mountains of New Mexico during the 2011-12 deer hunting season. With the assistance of cooperating landowners, TPWD, TAHC, and USDA-APHIS-Wildlife Services biologists and veterinarians collected samples from 31 mule deer as part of a strategic CWD surveillance plan designed to determine the geographic extent of New Mexico’s findings. Both infected deer were taken from the Hueco Mountains of northern El Paso and Hudspeth counties.

CWD is a member of the group of diseases called transmissible spongiform encephalopathies (TSEs). Other diseases in this group include scrapie in sheep, bovine spongiform encephalopathy (BSE or mad cow disease) in cattle, and Cruetzfeldt-Jakob disease in humans. CWD among cervids is a progressive, fatal disease that commonly results in altered behavior as a result of microscopic changes made to the brain of affected animals. An animal may carry the disease for years without outward indication, but in the latter stages, signs may include listlessness, lowering of the head, weight loss, repetitive walking in set patterns, and a lack of responsiveness. CWD is not known to affect humans.

Tissue samples were initially tested by the Texas Veterinary Medical Diagnostic Laboratory in College Station, with confirmation by the National Veterinary Services Laboratory in Ames, Iowa.

“Now that we have detected CWD in Texas, our primary objective is to contain this disease,” said Carter Smith, TPWD Executive Director. “Working collaboratively with experts in the field we have developed protocols to address CWD and implementation is already under way.”

There is no vaccine or cure for CWD, but steps have been taken to minimize the risk of the disease spreading from beyond the area where it currently exists. For example, human-induced movements of wild or captive deer, elk, or other susceptible species will be restricted and mandatory hunter check stations will be established.

“This is obviously an unfortunate and rather significant development,” said TPW Commission Chairman, T. Dan Friedkin. “We take the presence of CWD very seriously and have a plan of action to deal with it. The Department will do whatever is prudent and reasonable to protect the state’s deer resources and our deer hunting heritage.”

Although wildlife officials cannot say how long the disease has been present in Texas or if it occurs in other areas of the state, they have had an active CWD surveillance program for more than a decade.

“We have tested more than 26,500 wild deer in Texas since 2002, and the deer breeding industry has submitted more than 7,400 CWD test results as well,” said Mitch Lockwood, Big Game Program Director with TPWD. “But that part of West Texas is the toughest place to conduct an adequate CWD surveillance program because so few deer are harvested out there each deer hunting season. Thanks to the cooperation and active participation of several landowners, we were able to begin getting an idea of the prevalence and geographic distribution of the disease without needing to remove many deer.”

The TAHC regulates cervid species not indigenous to Texas such as elk, red deer, and sika deer. TAHC oversees a voluntary CWD herd monitoring status program with the intent to facilitate trade and marketability for interested cervid producers in Texas. Cervid herds under either TPWD or TAHC authority may participate in the commission’s monitored CWD program. The basis of the program is that enrolled cervid producers must provide an annual herd inventory, and ensure that all mortalities during the previous year were tested for CWD and the disease was not detected.

Wildlife biologists, hunters, and landowners would certainly have preferred for Texas mule deer populations to have not been dealt this challenge, but TPWD and TAHC have developed a CWD Management Plan that includes management practices intended to contain the disease. The management plan includes input from the CWD Task Force, which is comprised of deer and elk producers, wildlife biologists, veterinarians and other animal-health experts from TPWD, Texas Animal Health Commission, Department of State Health Services, Texas A&M College of Veterinary Medicine, and USDA.”

The deer disease was first recognized in 1967 in captive mule deer in Colorado. While mule deer populations in that state declined, but the economic impact on elk and deer hunting activities has never been quantified. CWD has been documented in captive and/or free-ranging deer species in 19 states and 2 Canadian provinces. Dr. Dee Ellis, State Veterinarian and TAHC Executive Director, also had this to say about Texas’ situation, “We know that elk in southern New Mexico are also infected with CWD. It will take a cooperative effort between hunters, the cervid industry, and state/federal animal health and wildlife agencies to ensure we keep this disease confined to southern New Mexico and far West Texas. I am confident however that will be able to do that, and thus protect the rest of the Texas cervid industry.”