Learning about an individual animal’s health is important not only for the well-being of that animal but also as part of an assessment of the health of the population. For example, a disease or health condition identified in one panther may provide clues to health risks for other panthers and allow early treatment and intervention, thereby minimizing impacts to the population. In this section you can learn about veterinary examination of both live panthers at capture as well as panthers that have died. You will also find information on several diseases known to affect panthers, methods used to treat and prevent these diseases, and ways that you can help to control disease in wild panthers.
Before Florida Fish and Wildlife Conservation Commission (FWC) veterinarians can conduct a medical exam of a Florida panther, the capture team and their specially trained dogs must chase one up a tree. Prior to darting a treed panther, biologists observe the panther from a distance, looking for obvious signs of disease and, in females, for signs of pregnancy. If they determine the animal cannot be safely sedated, the capture is aborted in order to ensure the safety of the animal.
Each captured panther will receive a full exam by a veterinarian and be continually monitored while under anesthesia. Vital signs, such as temperature, heart and respiration rates, and depth of anesthesia are closely monitored throughout the capture.
Depending on their vaccine history, panthers more than six months old are vaccinated against several diseases including feline leukemia virus, rabies, feline viral rhinotracheitis, feline calicivirus and feline panleukopenia. These diseases could pose a significant risk to an individual panther or to the panther population. If veterinarians determine an adult panther is being negatively impacted by parasites (i.e. poor body condition), it is also dewormed.
The veterinarian establishes an intravenous (IV) catheter that allows the administration of fluids in order to maintain hydration. This also allows for immediate treatment in the case of an emergency. Every panther receives eye lubrication to prevent damage to its eyes while it is under anesthesia. If needed, the veterinarian treats any wounds and injuries noted during the exam. Although this is a very rare occurrence, any panther with major injuries such as fractures or broken bones will be transported for appropriate veterinary care and rehabilitation.
Blood is collected from each panther and routine bloodwork (complete blood count and biochemistry) is performed, as well as infectious disease and toxin testing. A hair sample is collected and several small skin biopsies are taken from the ear for genetic analyses. Additional samples, such as cultures, fecal samples and skin scrapings, are taken if the veterinarian notes some potential issue with the panther such as a rash or abnormal growth.
Each panther during the exam receives a microchip for permanent identification. The microchip is placed under the skin, just as it is in pet dogs and cats, and allows for follow-up identification if the animal is handled in the future.
Biomedical information is critical not only to assessing the health of the individual animal but also for assessing risk factors for the population. This information allows implementation of appropriate health and management planning. A good example is the vaccination program the FWC initiated for feline leukemia virus following identification of an outbreak of this disease.
Florida Fish and Wildlife Conservation Commission veterinarians perform a complete necropsy (animal autopsy) on all panthers found dead in the wild. Any panther they suspect was killed illegally is sent to the U.S. Fish and Wildlife Service’s National Forensic Laboratory to be examined by board-certified veterinary pathologists. In all panther necropsies, a thorough examination of the dead panther can provide important information as to the true cause of death, as well as other factors affecting the panther’s health.
Each dead panther receives a complete external examination to document any abnormalities such as wounds, fractures, congenital abnormalities (i.e. kinked tail), and parasites. The panther is weighed, and multiple measurements of the animal are recorded. The panther’s age is estimated by size and weight but also by the wearing down of the panther’s teeth. Evidence of previous lactation (production of milk) can provide information as to whether or not a female has nursed kittens. Hair and tissues are collected for DNA analysis, and photos are taken of any significant findings.
Radiographs (X-rays) are taken of each dead panther to assess any traumatic injuries, such as recent or healed bone fractures or the presence of bullet fragments, and to check for a transponder chip (which would indicate the panther had been handled by scientists in the past). These images provide valuable clues as to the cause of death, as well as potential evidence if an animal has been illegally killed. FWC veterinarians have learned that many panthers suffer from traumatic injuries such as broken bones.
Following the external exam and radiographs, each dead panther receives a complete necropsy where all tissues are examined. Samples of blood and organs are collected and submitted to several specialized laboratories to analyze overall health of the animal at the time of death. Testing for infectious diseases (such as feline leukemia virus and pseudorabies virus) and toxins is also performed. Additional samples are collected, preserved or frozen, and saved for any future testing that may be indicated.
Following necropsy, some panther remains will be saved for educational purposes. Bones, such as skulls, may be saved and used for anatomical comparisons. Panthers also may be mounted as complete specimens for display in natural history museums and other educational facilities. These specimens serve as valuable tools in promoting education about the Florida panther.
Feline leukemia virus (FeLV) most commonly affects house cats but can be fatal to panthers. The Florida panther, as well as other North and South American puma populations, has historically not been infected by this virus. However, testing has shown increasing exposure of Florida panthers to the virus over the past 30 years, with many panthers developing active infections. While some panthers may be able to control and eventually clear a FeLV infection, many succumb to the disease. Of greatest concern is that once the virus crosses the species barrier, infection then could spread from panther to panther.
Between 2002 and 2004, an outbreak of FeLV resulted in the deaths of at least five Florida panthers, and since 2010, infections have been diagnosed in six additional panthers. Through genetic analyses of the infecting virus, biologists determined the outbreak likely came from a cross-species transmission from a domestic cat. Panthers are known to prey upon domestic cats that roam freely outdoors.
The clinical diseases resulting from FeLV infection in panthers, including anemia and septicemia, appear similar to those seen in domestic cats. However, progression of the clinical diseases appears to be quite rapid in panthers that are persistently infected, and most will die within a few months of infection.
Surveillance and management of FeLV in panthers
All panthers older than 2 months that are handled (alive or dead) by panther biologists are tested for FeLV. Veterinarians developed a protocol for live-captured panthers that test positive for FeLV in the field. Infected panthers are transported to a holding facility for care, treatment and re-testing. They only will be released back into the wild if a veterinarian verifies the panther cleared of the virus.
All live-handled panthers older than 2 months are vaccinated against FeLV. Initially, biologists targeted the area where FeLV positive panthers were first discovered. However, the vaccination protocol now calls for biologists to vaccinate all kittens older than 2 months and all adult panthers they handle.
What you can do to prevent this disease
Given the increasing urban-wildlife interface and the increasing Florida panther population, panthers are far more likely to encounter house cats. House cats should be raised as inside pets and never allowed to roam freely outdoors. Cat owners should also make sure their pet’s vaccinations, including FeLV if the cat spends time outdoors, are current. Each house cat that is protected from the virus and direct contact with panthers is one less threat to panther conservation.
Pseudorabies in the Florida Panther
Pseudorabies (also known as Aujesky’s disease) is caused by a herpes virus (unrelated to rabies virus) and can affect a variety of mammals. In Florida, wild hogs are the most common hosts for pseudorabies. Clinical signs of infection in domestic hogs can include reproductive and fetal abnormalities, fever, respiratory and neurologic disease and death.
About 35 percent of wild hogs in Florida carry the virus but that can rise to 50 percent or higher in some areas. Wild hogs typically do not show symptoms of the infection but they can infect predators that eat them. Reports of the disease in wildlife are rare but cases have been documented in raccoons, bears, Iberian lynx (an endangered cat in Spain) and Florida panthers. Panthers eat wild hogs, and their exposure to this disease is possible if the prey is infected and shedding live virus. Pseudorabies in panthers is typically fatal, with the disease progression likely to be very rapid and animals may die within 48 hours of the onset of clinical signs.
Surveillance and management of pseudorabies in panthers
Pseudorabies is likely much more significant in Florida panthers than previously thought. New diagnostic techniques are allowing researchers to test for the disease in panthers whose deaths were undiagnosed. Pseudorabies virus is now known to have been the cause of death in at least eight Florida panthers and may have been responsible for many more. Pseudorabies is currently believed to be the third leading cause of death among Florida panthers, following intraspecific aggression and vehicle collision. To date, no evidence of prior exposure and subsequent recovery from this infection has been documented in live panthers. These results are consistent with a rapid and fatal disease course where the infected animal dies. Currently, there is no commercially available vaccine to prevent pseudorabies in panthers. Research into a safe and effective vaccine for panthers is needed, and vaccination may play a role in the future management of pseudorabies in panthers.