Chronic wasting disease in Florida: What to know 

Chronic wasting disease poses a significant threat to cervid populations throughout North America. The disease has the potential to greatly reduce and endanger deer populations across the country.  

Unlike illnesses caused by viruses, bacteria or fungi, CWD is a prion disease. Prions are healthy proteins found in the body that misfold, becoming deformed. As they encounter new proteins, they trigger the same misfolding, causing a condition known as spongiform encephalopathy. The term “spongiform” refers to the sponge-like appearance of infected brain tissue under a microscope due to the abundance of folded proteins.  

Since recording the first Floridian case of CWD in 2023, state health officials and researchers continue to closely monitor the area to prevent the disease from spreading.

Chronic wasting disease basics

CWD was first detected in captive deer in 1967 and in wild deer in 1981. Since then, the disease has been reported in wild deer in over half of the U.S. states. It’s possible that CWD is also active in other states but has yet to be reported. Once the disease is established in an area, the CWD prions can stay in the soil and water for years.

The prions gradually build up in the brain, destroying neurons and irreversibly damaging brain tissue. CWD eventually results in dramatic weight loss, trembling, staggering, listlessness and other neurologic symptoms before inevitably killing the host. Although some prion diseases infect humans, there have been no reported cases of CWD in people.

Only mammals in the deer family are susceptible to CWD. No evidence has shown that the disease can spread to other animals or to people. However, the disease is beginning to spread to other cervids internationally, as reported in Finland, Norway, Sweden, South Korea and four Canadian provinces.

Chronic wasting disease in Florida

The first confirmed case of CWD in Florida was reported in June 2023 near the Alabama border in Holmes County. A road-killed deer tested positive for the highly contagious disease during routine surveillance by the Florida Fish and Wildlife Conservation Commission.

This discovery led the FWC to implement a CWD response plan in partnership with the Florida Department of Agriculture and Consumer Services. The plan aims to manage and mitigate the spread of CWD within the management zone covering parts of Holmes, Jackson and Washington counties. The FWC collects samples from the zone to further assess the spread of the disease. The results from this sampling effort will inform resource managers so they can react with appropriate management strategies.

Chronic wasting disease transmission

The transmission routes of CWD are still unclear. Research suggests direct and indirect contact with infected bodily fluids could transmit prions to a new host. Once the disease has been established in an environment, the prions will remain infective in water and soil for at least two years.

Ticks may also contribute to transmission by ingesting prions and passing them from host to host. Additionally, prions can be absorbed by plant roots, stored in plant material and transferred to animals when eaten. This suggests that the movement of livestock feed could contribute to disease spread.

Symptoms of chronic wasting disease

Once an animal is exposed to CWD, the infection can be asymptomatic for up to three years. However, rapid degeneration begins once symptoms appear. The degeneration will likely cause the animal to succumb to the disease within four months.

Populations most vulnerable to chronic wasting disease

All cervids are vulnerable to CWD, specifically white-tailed deer, mule deer, black-tailed deer, Rocky Mountain elk and moose.

Across the country, the overall prevalence of CWD in wild deer and elk remains low. However, infection levels can be significantly higher in regions where CWD has persisted for years or decades. Nationwide, some states report rates surpassing 10%, with hotspots experiencing prevalence as high as 25%. In captive deer populations, the rates are substantially elevated due to their proximity to other deer.

Chronic wasting disease diagnosis

Diagnosing CWD requires analyzing samples from the animal’s brain, spinal cord and lymph nodes. For this reason, it can only be diagnosed in deceased animals. Current research is exploring how to detect CWD in live animals by analyzing samples of lymph tissue, feces and nasal brush.

Only United States Department of Agriculture Animal and Plant Service-approved veterinary diagnostic laboratories may perform CWD testing.

If a farmer suspects one of their deer of having CWD, they should contact an accredited veterinarian. If a wild animal is raising concerns, veterinarians should inform state and federal authorities to determine how to collect and submit samples.

Multiple accredited laboratories are available and have the capacity to test samples collected by individual hunters. Veterinarians should always verify with the diagnostic laboratory that samples are collected, packaged and shipped correctly.

Chronic wasting disease treatment

There is no treatment or vaccine for CWD. Prions are malfunctioning proteins, so antibiotics, antivirals and antifungals have no effect.

The only effective way to eliminate prions from an environment is through decontamination, which includes incineration, autoclaving or harsh chemical treatments. Of course, these methods are impractical for outdoor ecosystems, making management difficult.

Prions can attach to various soils and minerals, potentially creating environmental reservoirs for infection. Research by the National Wildlife Research Center found that soil bacterium-producing enzymes successfully degraded CWD prions bound to contaminated soil.

While it may be impossible to eliminate prions from the environment completely, applying this topical enzyme treatment could help limit indirect disease transmission to cervids. 

Chronic wasting disease prevention

Researchers and health professionals across the U.S. are prioritizing CWD prevention methods. Once CWD has been established in an environment, it is difficult to control its spread and virtually impossible to eradicate. In animals, prevention often means purposefully lowering the deer population in infected areas.

When hunting in areas with CWD activity, follow these steps to reduce your risk of contact with the disease:

• Do not shoot, handle or eat animals that look sick or act strangely
• Do not touch or eat meat from animals found dead
• When field-dressing a deer or handling meat:
  • Wear latex or rubber gloves
  • Avoid handling its internal organs, especially the brain or spine
  • Do not use knives or other tools you use in your kitchen

Check state wildlife and health department for recommendations before you hunt. See if they recommend or require testing animals for CWD in the hunting area.

Have the deer or elk tested for CWD before you eat the meat. If you have an animal commercially processed, ask that your animal be processed individually to minimize mixing meat from other animals. If your animal tests positive for CWD, discard it immediately. Although there is no current evidence of a person contracting CWD, caution is advised because other fatal prion diseases can be transmitted from animals to humans.

To minimize the potential economic impact of CWD and maintain strong trade in cervids and their products, farmers should buy animals from a trusted source and participate in the USDA’s CWD Voluntary Herd Certification Program. This program combines biosecurity and surveillance practices to reduce CWD risk.

Additional resources