Introduction

Non-domestic felids include 37 different species but only few are commonly found in felid refuges. Information on felid biology, husbandry and medical care has been reported elsewhere.³ Veterinary care of felids housed in felid sanctuaries presents unique challenges which may be novel to the veterinary practitioner. Although the anatomy, physiology and pathophysiology of diseases are similar to domestic felids, differences do exist. One of the major considerations in providing veterinary care to non-domestic felids are pronounced size differences between species, ranging from several pounds to over 500 pounds in body weight. While diagnostic, medical and surgical procedures are similar to domestic cats, most non-domestic felids except for very young animals are dangerous and require immobilization for diagnostic procedures. However, since most felids housed in refuges are acquired from private owners unable to keep the animal once they mature, small circuses or roadside attractions as well as from other rescue operations, many non-domestic felids are used to contact with humans. In some instances it is possible to collect diagnostic samples (e.g., hair, skin scrapings, venous blood sample) without chemical immobilization.

A major challenge when working with non-domestic felids in rescue facilities is the often unknown medical history of the patient. This includes information on husbandry practices such as nutrition and exposure to other animals. Most animals arrive with no or incomplete histories and it is recommended to establish a quarantine protocol for all new arrivals. During quarantine a thorough physical examination, fecal screens and further diagnostics such as CBC and plasma biochemistries should be performed. If indicated imaging modalities such as radiography and/or ultrasonography may need to be utilized to characterize the full extent of any abnormalities. In cases with no vaccine history the animals should be vaccinated against the most common felid viral pathogens. For future reference, it is also advisable to collect serum for banking while the animal is still in quarantine.

Diagnostic techniques and protocols for non-domestic felids are almost identical to domestic cats. A venous blood sample can be collected from the jugular vein, cephalic vein, saphenous vein or from the lateral tail vein in larger cats. In trained felids, a venous blood sample may be collected without chemical restraint. Techniques for radiography, ultrasonography as well as endoscopic techniques are identical to domestic species. Advanced imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly used in non-domestic felid species. However, there is a need to establish normal CT and MRI reference findings in order to diagnose abnormalities. Surgical techniques follow the same protocols established in domestic felids however post-operative management is often more difficult in non-domestic felids, e.g., management of postoperative pain and other supportive care measures.

Preventative medicine is oft most importance in the management of non-domestic felid collections. These should include regular physical examinations, fecal examinations and the development of a vaccination protocol. In endemic areas, heartworm testing should be performed regularly and all cats should receive heartworm preventatives such as ivermectin.

Restraint and Anesthesia

Protocols on felid anesthesia including effective drugs and dosages have been published previously. For more detailed information on anesthetic techniques, including monitoring techniques as well as supportive care measures, the reader is referred to C. Gunkel et al. 2003.¹ Only very young felids are safe to handle especially when they are used to human contact. Adult and larger species are dangerous and should be safely restraint to prevent injury to the animal and personnel. For short procedures such as vaccinations, small felids (< 10 kg body weight) can be restraint with a net and handled with heavy leather gloves. For longer diagnostic procedures, small cats should also be anesthetized to minimize stress and potential injury to the patient. Large non-domestic felids cannot be safely restraint manually and require administration of immobilizing agents to facilitate handling and diagnostic procedures. It is recommended to have different size squeeze cages available at the facility to accommodate the species housed. It is ideal if animals can be transferred from their regular enclosure/cage directly into the squeeze cage. Administration of immobilizing agents can then be facilitated via hand injection. In some cases, hand injections through cage bars are possible if the animal is accustomed to human contact, however one should consider that felids are very fast and may react violently to the injection. Safety is of most importance to prevent injury of the veterinarian or the animal which may bite into the cage bars and damage their teeth. In all other cases, administration of the immobilizing agents via a remote drug delivery system is recommended. Many devices are available commercially and it depends on the experience of the practitioner, the distance to the animal as well as the size of the animal which system is being used.

A variety of different anesthetic agents have been reported to provide safe and effective anesthesia in non-domestic felid species. In small species, anesthesia can be induced with isoflurane or sevoflurane administered in a chamber. Prior to anesthesia the patient should be fasted and carefully evaluated for any underlying disease processes which may require adjustments to the anesthetic regimen, e.g., lower dose of the anesthetic in severely compromised animals. If possible, the cat should be premedicated with a benzodiazepine (e.g., midazolam 0.1 mg/kg) administered either orally or intramuscularly to facilitate smooth induction and lower the total dose of induction agent required. Most protocols are based on the administration of the dissociative anesthetic agent ketamine HCl (2 – 4 mg/kg IM) combined with synergistic agents such as alpha 2 agonists (xylazine, medetomidine, dexmedetomidine) and/or benzodiazepines (diazepam, midazolam). In large felids such as mature lions and tigers, the author prefers intramuscular administration of dexmedetomidine (15-25 µg/kg) followed by intramuscular ketamine (2-4 mg/kg) following achievement of heavy sedation by the alpha 2 agonist. This will provide heavy sedation for approximately 20-30 minutes adequate to perform a thorough physical examination and facilitate sample collection (e.g., venous blood sample, urine, or collection of biopsies and aspirates). At the end of the procedure, the effects of dexmedetomidine can be reversed by administration of the alpha 2 agonist atipamezole. For diagnostic procedures lasting longer than 30 minutes, maintenance of anesthesia with an inhalational agent (isoflurane or sevoflurane) is recommended. All anesthetic agents have pronounced cardiopulmonary depressant effects and equipment should be available to provide supplemental oxygen and assist ventilation. Monitoring is identical to domestic felids and heart rate, respiratory rate, arterial blood pressures, ECG, pulse oximetry as well as endtidal-CO₂ concentrations should be monitored and recorded. Pre-, intra- and postoperative analgesia should also be provided when a painful procedure is being performed. Opioid agents are most effective in managing acute pain while non-opioid agents such as meloxicam are routinely used for the management of chronic pain.

Non-Infectious Diseases

Commonly, felids presented to refuges have no previous medical history and every attempt should be made to collect as much information as possible from the previous owner. Non-domestic felids are often presented with conditions resulting from inadequate husbandry practices such as improper nutrition and lack of preventative medicine measures. Diets low in calcium may result in metabolic bone disease. It is recommended to feed commercially available diets and to supplement with vitamins and minerals. Lack of dental care may result in problems including tartar build-up or broken canine teeth. Non-infectious diseases most commonly seen in non-domestic felids include metabolic bone disease, foreign body ingestion, toxicities, orthopedic conditions including fractures as well as geriatric changes including osteoarthritis. Neoplasia reported from non-domestic felid species are similar to those reported in domestic cats and are commonly diagnosed in older animals. Mammary cancer has been reported in several non-domestic felid species. Chronic renal disease is commonly diagnosed in older non-domestic felids. Elevations of renal parameters on blood chemistry will determine the degree of renal impairment. Supportive care measures are similar to domestic cats however difficulty in handling the patient will often limit the extent of medical care.

Surgical indications and techniques are identical to domestic felids and have been described in the literature. Captive felids especially those kept as "pets" may require corrective surgery for improper declaw and defanging procedures The most difficult aspect of surgery in large non-domestic felid species is provision of post-operative care including wound management, administration of effective analgesia and antimicrobial therapy which may also be very expensive.

Infectious Diseases

Non-domestic felids are susceptible to the same pathogens as domestic felids and a large variety of viral, bacterial, fungal and parasitic agents have been identified in exotic felid species. All cats are susceptible to rhinotracheitis, calicivirus, feline infectious peritonitis, feline leukemia and feline immunodeficiency virus. Clinical symptoms resemble those seen in domestic cats. All felids at a refuge facility should be vaccinated against rabies, feline rhinotracheitis, feline calicivirus and feline panleukopenia. Vaccination against feline leukemia has to be evaluated on an individual basis, e.g., facility has had previous problems with feline leukemia. In cases were vaccination history is unknown the animal should be considered unvaccinated and receive above vaccines before being introduced into the collection.

A variety of bacterial pathogens have been associated with disease in non-domestic felids. Bacterial dermatitis, pneumonia, gastro-enteritis as well has bacterial infections of the urogenital tract are commonly diagnosed. Gastritis is commonly seen in non-domestic felids and a diagnosis is made utilizing gastroscopy and collection of diagnostic specimen for culture and histopathology. Pyometras have been reported in non-domestic felids especially lions and tigers.² A diagnosis of pyometra is often based on clinical signs (vaginal discharge), complete blood cell counts indicating leukocytosis and hyperproteinemia, and plasma biochemistries. While abdominal radiographs are often nonspecific, abdominal ultrasonography often reveals a fluid-filled distended uterus. Treatment consists of systemic antimicrobial therapy and ovariohysterectomy of infected animals. Lions appear to be at an increased risk for the development of pyometras when compared to other felid species. Ovariohysterectomy of female lions in non-breeding situations should be considered. Antimicrobial treatment of bacterial infections follows a similar protocol established for domestic cats. It is recommended to perform culture and sensitivity testing prior to antimicrobial therapy. For treatment of bacterial infections, antimicrobial agents are preferred which are safe to use, have minimal side-effects, can be given orally and come in concentrations suitable to medicate large felid species. Long-acting injectable antimicrobial agents are recommended for animals which may not take oral medications. This will eliminate the need for repeated daily injections and further stress of the animal.

Fungal dermatitis as well as fungal pneumonia has been reported in non-domestic felids. Diagnosis of a fungal etiology requires collection of appropriate diagnostic samples such as aspirates, biopsies and blood or urine for serologic testing. In cases of suspected fungal pneumonia radiographs of the thorax is recommended to evaluate the extent of the infection. Blastomycosis caused by Blastomyces dermatitidis has been diagnosed in non-domestic felids in the SE United States. Typically, difficulty breathing or skin lesions may be observed in infected animals. Diagnostic tests include complete blood cell count, plasma biochemistries, urine analysis, biopsies and scrapings from skin lesions for identification of fungal organisms. Thoracic radiographs are recommended to evaluate the patient for pulmonary lesions. In animals with pulmonary lesions, collection of a transtracheal wash and identification of fungal organisms will help to confirm a diagnosis. Administration of antifungal agents (e.g., itraconazole) should last at least 4 weeks and includes regular monitoring and testing of the patient. Antifungal therapy should only be discontinued if the animal tests negative for blastomycosis.

Internal and external parasites have been reported in non-domestic felids and fecal screens should be performed while the animal is in quarantine. Regular fecal examinations of all cats at the refuge and treatment of positive animals with anthelmintic drugs is recommended. Drugs and dosages established for domestic cats can safely be used in non-domestic species.

References

1.  Gunkel, C., Lafortune, M. (2007) Felids. In: West, G., D. Heard, and N. Caulkett (eds.). Zoo Animal & Wildlife Immobilization and Anesthesia. Blackwell Publishing, Ames, Iowa. Pp. 443-457.

2.  McCain, S., Ramsay, E., Allender, M., Souza, C., Schumacher, J. (2009) Prevalence of pyometra in a large felid collection. J Zoo Wildl Med 40: 147-151.

3.  Wack, RF. (2003) Felidae. In: Fowler, M.E., and R.E. Miller (eds.). Zoo and Wild Animal Medicine, 5th ed. W.B. Saunders Co., Philadelphia, Pennsylvania. Pp. 491-501.