Canine Distemper Outbreak in Ferrets September – December 2022
As you likely have heard, there have been numerous cases of canine distemper (CD) in recently shipped ferrets from Marshall Farms (MF). It has been reported in many locations in the US and now Canada. Stores may have put holds on selling ferrets, or may not be receiving them at this time. All major distributors as well as stores receiving ferrets directly have been affected. It is unknown at this time how many ferrets have died, but the number is substantial. At present, it is unknown if it has ended, as ferrets have been diagnosed within the past month.
What We Know So Far
This fall, one of the largest pet store chains that sells ferrets had several acutely sick and dying kits, that were recently received at the stores. PetCo had diagnostics done and confirmed CD. Reports back to MF have led to epidemiologic tracing, diagnostic testing being conducted at universities and other veterinary laboratories. At this time, it appears a vaccine that MF started using in late summer, along with factors at this time that are still unknown, appears to have become virulent with many ferrets developing CD within a few days to up to 3 weeks. The strain found in the dying ferrets was discovered to be identical genetically to the MLV in the vaccine. MF is continuing to work on trying to figure out why this has happened. This is an extremely uncommon event that a licensed vaccine causes the disease it was designed to prevent.
Disease caused by this CD virus appears to move much faster in these 7–9-week-old kits, with the first signs of diarrhea and loss of appetite, and within 24 hours discharge from the eyes and nose, open-mouth breathing, dehydration, fever, and death within 48-72 hours. With intensive medical treatment, it may be possible to bring a ferret through this, however treatment needs to initiated at the first signs. The ferrets share the history of being shipped within the past 2 weeks of the appearance of clinical signs.
What Veterinarians Need to Do:
- Ensure all ferrets in your practice are current on their distemper vaccination.
- If you need to visit a store or facility – wear an N95 mask within the store. When you leave, disinfect hands, change clothes before going in your home (placing clothing, shoes immediately in the laundry), and if possible shower. The virus can also reside in our nasal passages, so consider doing a nasal rinse. Avoid direct contact (including breathing air space) with any ferrets in/at your practice preferably for several hours. Surfaces such as inside your car should be disinfected (most that kill COVID kill distemper). The virus cannot survive without moisture on surfaces for very long, so drying, heat, sunlight all naturally disinfect surfaces.
- For shelters, use safety precautions like those put in place for influenza or COVID prevention. Limit public access. Ferrets being surrendered – place in a quarantine area preferably with a separate entrance and air system. Vaccinate immediately. For personnel going into the quarantine room, use shoe covers, gowns or Tyvek-type suits, gloves, N95 masks, eye covering like safety glasses, and hair covers. Remove the PPE as you exit the room. As a common disease preventative for all diseases, shelter personnel are encouraged to wear scrub type dedicated clothing, that is clean and not contaminated by environments other than the immediate transportation used to get to the shelter. Better still would be to have staff change into dedicated clothing at the shelter itself.
Effective Treatment for Ferrets with CD:
It is suggested that a complete workup should be done if any ferret is presented that is ill that has a history of being sold or housed in a pet store within the past 3-4 weeks. Most of these will be ferrets 7-11 weeks old. Take serum for CD titer. You may also want to take a conjunctival swab for PCR. Differentials include influenza and COVID.
- Vaccinate with a licensed subunit vaccine such as PureVax® Ferret, or off-label Nobivac® puppy. Nobivac® is not licensed for use in ferrets in the US, so an off-label waiver should be supplied to the owner. Before vaccination, pre-treat with diphenhydramine (dose below).
- Vitamin A (50,000 IU SC q 24 h X 2 d)
- Interferon (60-120 units SC q 24h for 3-7 days)
- Meloxicam (0.2 mg/kg SC q 24h for 3-7 days
- Famotidine (2.5 mg/ferret SC q 24h for as long as ill – can switch to oral once the ferret is eating well on its own)
- Diphenhydramine (0.5-2 mg/kg IM, IV, SC or PO q 8-12h prn)
- Buprenorphine (0.01-0.05 mg/kg IV, IM, SC q 8-12h if exhibiting signs of pain or is dyspneic
- General supportive care:
b. Amoxicillin/clavulanate (12.5 mg/kg PO q 12h)
c. Hand feeding: Dook Soup (recipe below) enough to maintain weight if not eating on its own.
d. Vitamin C added to the drinking water (0.2 mg/mL – change twice daily)
e. Nebulization: 20 minutes 1-3X a day. Plain saline or saline with a bronchodilator can be used – same strength as used with rats or birds.
f. Keep nostrils and eyes free of discharge. Ophthalmic drops both eyes- ofloxacin or other broad spectrum q 8h for minimum 5 days.
Again, the best thing right now for everyone is to make sure all ferrets are current on their distemper vaccinations. There is a whole team working on solving this problem and stopping it.
Timely updates will be posted on Exotic DVM Forum, AEMV and VIN. If anyone has suspected cases, please contact Cathy Johnson-Delaney at firstname.lastname@example.org
Below are kits with CD in this outbreak They are approximately 8 weeks old and clinical signs began within 5 days of shipment.
Hand-Feeding, Dook Soup Recipe
Recommended for severely anorectic ferret, first few meals:
Emeraid Carnivore®, Lafeber Co.
Recovery®, HBD Co.
Next meal can be Critical Care Carnivore®, Oxbow Co.
When hydration is corrected, then switch to Dook Soup:
Dook Soup for CD Kits 2022
- Mix 1 Cup Marshall Ferret Regular (this is what the kits are all on to maintain MF guarantee) food with adequate water until it is fully softened into a thick soup-like consistency.
- Add in 1 heaped teaspoon or Emeraid Carnivore®, Recovery®, or Critical Care Carnivore®. Additional water or low-sodium organic chicken broth usually needed to make a soupy consistency which can easily be fed through a large bore syringe or off a spoon.
- Best if the soup is slightly warmed or at least is room temperature. Extra volume can be stored, covered and refrigerated for 24 hours.
- Weigh ferret daily. Increase volume and/or frequency of feedings for weight gain. Usually amount to start a ferret is 30-40 mL/kg body weight, but once the ferret will eat soup from a bowl on its own, it may require more.
Cathy A. Johnson-Delaney, DVM