Assessing the Sick Ferret

Introduction

The average small animal veterinarian may easily become comfortable with ferrets. Ferrets are hardy and relatively stoic, and as members of the order Carnivora, ferrets are predator species that approach the world in a manner similar to cats and dogs. A relatively small number of medical problems are seen very commonly in ferrets. Careful study of these conditions and attention to the unique aspects of ferret anatomy and behavior will prepare the veterinarian for basic emergency care of the ferret (Fig 1).

ferret sick fecal staining

Figure 1. Take unique aspects of ferret anatomy and behavior into account, when assessing the clinically ill patient.

Unique features of the ferret history

While obtaining a detailed history, confirm that the owner feeds a diet containing high-quality, animal-based dietary protein such as a ferret food or premium cat food. Also ask if the ferret drinks from a water bottle or bowl in case hospitalization is required.

How is the ferret housed? Pet ferrets are often kept in large, multi-level cages. When released from their cages, confirm that the environment has been “ferret-proofed” to minimize the risk of foreign body or toxin ingestion and accidents.

As part of the medical history be forewarned about unique clinical signs in the ferret. Nausea may manifest as copious drooling or ptyalism and vigorous pawing at the mouth. Loud teeth grinding or bruxism is often seen with abdominal pain.

Unique features of the ferret exam

Common diseases

Common disease conditions in the ferret include adrenocortical disease, insulinoma or pancreatic beta cell tumor, and lymphosarcoma. Influenza virus is a zoonotic condition that may be transmitted from humans to ferrets (or vice versa).

Back problems like intervertebral disc disease are extremely rare in ferrets, because the ferret spine is extremely flexible.

Visual examination

Ferrets are nocturnal creatures so they are often asleep when presented. Ferrets are often sound sleepers as well so they may need to be roused from a deep sleep. Once the ferret is fully awake it should be curious, active, and playful. Normal, active ferrets also like to burrow in toweling or other cloth. The scientific name of the ferret Mustela putorius furo literally translates as ‘‘stinky thief”. This name reflects the curious, sometimes mischievous, nature of the ferret and their distinctive, musky odor.

 

Physical examination

  • Evaluate the cardiopulmonary system first:
    • The apex beat is found more caudally than in the cat or dog since the heart sits between the sixth and eighth ribs (usually 3-4 ribs caudal to elbow).
    • A common finding is a prominent respiratory sinus arrhythmia.
  • Most ferrets in the United States have two small, round tattoos on the inside of the pinna (see below). These tattoos indicate the from a facility called Marshall Farms. One dot indicates the ferret has been descented and the second dot indicates neutering (Fig 2).

    Two small round tattoos

    Figure 2. Two small round tattoos on the inside of a ferret. Click image to enlarge.

  • Lymph nodes may feel enlarged in large males or overweight individuals due to the presence of surrounding fat, however the underlying nodes still feel soft and pliable. Firmness or asymmetry of the lymph nodes suggests lymphadenopathy.
  • Ferrets normally have relaxed abdomensthat are easy to palpate.
    • The normal ferret spleen is relatively large measuring approximately  5 cm long, 2 cm wide, and 1 cm thick.
    • Splenomegaly is a common, incidental finding in ferrets over 1 year of age. Splenomegaly is most frequently caused by extramedullary hematopoiesis.
  • Since adrenocortical disease is so common, look for evidence of alopecia,particularly over the flanks, shoulders, and tail base. Seasonal alopecia is also a common finding in which fur falls out, typically along the tail, and then regrows within several weeks.
  • Evaluate the prepuce on the ventral abdomen just caudal to the umbilicus.  Excessive licking may occur with discomfort caused by urethral obstruction so check for redness.
  • Also look for vulvar swelling or discharge, most commonly associated with adrenocortical disease.
  • At the end of your complete examination, set the ferret down and allow it to walk around on the exam room floor. Important signs of generalized weakness may include loss of the normal hump in the back while moving as well as rear limb weakness or ataxia.

Unique features of ferret clinical pathology

Complete blood count and serum biochemistry values are similar to those found in other mammals with few exceptions:

  • Normal hematocrit is relatively high with normal values ranging from 46-61%
  • Fasting blood glucose levels normally range from 90-120 mg/dL.
  • Creatinine normally ranges between 0.1-0.3 mg/dL and is almost always less than 0.5 mg/dL. Incremental elevations between 0.7-1.0 mg/dL signify azotemia in the ferret.

Clinicians sometimes use inhalant anesthesia to obtain blood samples from ferrets. Be aware that isoflurane and sevoflurane significantly decrease hematocrit, hemoglobin, plasma protein, red blood cell count, and white cell count levels. The maximum effects occur 15 minutes after induction, and values do not return to their original state until approximately 45 minutes after anesthesia.

References