Red squirrels (Sciurus vulgaris)

Red squirrels (Sciurus vulgaris)

Note: It is illegal to release grey squirrels (Sciurus carolinensis) back into the wild across all the devolved administrations of the UK and a license is required from the relevant authority to keep grey squirrels in captivity. The formulary below can be used appropriately for grey squirrels.

Drug	Dose	Comments
Anaesthetics: Careful monitoring (including temperatures as hypothermia is common) and provision of oxygen is advised with the combinations below. Gaseous anaesthesia can be used in red squirrels.
Alfaxalone + dexmedetomidine + midazolam	Alfaxalone (15 µg/kg) + dexmedetomidine (40 µg/kg) + midazolam (0.3 mg/kg) i.m.a	Good quality of general anaesthesia for surgery, with limited cardiovascular effects and good intraoperative muscle relaxationa Dexmedetomidine may be reversed at the end of surgery using atipamezole.
Ketamine + medetomidine	Ketamine (5 mg/kg) + medetomidine (0.05–0.1 mg/kg) i.m.f Ketamine (75 mg/kg) + medetomidine (0.5 mg/kg) i.p., i.mb,c,d,e	Relatively low dose rates of this combination of drugs have been reportedf to produce immobilization in squirrels Medetomidine may be reversed after 20 minutes using atipamezole Much higher dose rates have been used to provide 20–30 minutes surgical anaesthesiag Individual animal drug responses may vary and therefore suggested dose rates should be used only as a guideline Medetomidine may be reversed after 20 minutes using atipamezole
Ketamine + dexmedetomidine + midazolam	Ketamine (15 mg/kg) + dexmedetomidine (40 µg/kg) + midazolam (0.3 mg/kg) i.m.a	Good general anaesthetic for surgical procedures, with rapid relaxation and recoverya
Midazolam	2.5 mg/kg i.p., i.m.c	Sedation
Atipamezole	5 x dose (mg/kg) medetomidine or 10 x dose (mg/kg) dexmedetomidine used	Reversal of medetomidine: 5 times the medetomidine dose (i.e. equal volume of the 5 mg/ml atipamezole solution) Reversal of dexmedetomidine: 10 x dose of dexmedetomidine (0.5 mg/ml solution) (i.e. equal volume of the 5 mg/ml atipamezole solution when 0.5 mg/ml solution of dexmedetomidine is used) In common with most species, a delay in reversal of medetomidine/dexmedetomidine of at least 20 minutes after the administration of combinations with ketamine is recommendedd
Analgesics:
Buprenorphine	0.05 mg/kg s.c. q8–12hb	Opioid analgesics for control of mild to moderate pain
Butorphanol	2 mg/kg s.c. q4hb,f	Opioid analgesics for control of mild to moderate pain
Carprofen	5 mg/kg s.c. q24hb,f	The usual considerations for the careful use of NSAIDs in dehydrated, hypovolaemic or hypertensive animals, as well as those with underlying gastrointestinal disease, should be observed
Ketoprofen	1–3 mg/kg i.m., s.c. q12–24hf
Meloxicam	1–2 mg/kg s.c., p.o. q24hf
Morphine	0.5–2 mg/kg i.m., s.c. q2–4hf	Lower does should be used in clinically compromised animals
Antibiotics: Antibiotic use (both appropriate and inappropriate) imposes a powerful selection pressure on bacteria and is the primary driver of antibiotic resistance. Eliminating unnecessary use in people and animals is, therefore, essential to safeguard this invaluable resource. Prudent use is especially indicated where treated wild animals are being returned to the wild. The reader is referred to the Guidelines for responsible antibiotic use, for further information (https://www.bsavalibrary.com/content/formulary/backmatter/exotic-petsguidelinesforresponsibleantibacterialuse)
Enrofloxacin	10 mg/kg s.c., p.o. q24hc,f,g	Fluroquinolones should ideally be reserved for infections where culture and sensitivity testing predict a clinical response and use of first- and second- line antimicrobials would not be considered effective
Metronidazole	20 mg/kg s.c. q24hc,f 10–20 mg/kg p.o. q12g
Trimethoprim/sulphonamide	15–30 mg/kg i.m., s.c., p.o. q12hg
Parasiticides: Parasiticide use in wildlife may reduce the development of natural resistance to parasites, as well as exerting selection pressure on organisms which can lead to drug resistance and may risk environmental contamination. Careful selection and use of these drugs, only where there is a clinical need, and then using narrow spectrum products, is essential where treated wild animals are being returned to the wild. Reader is referred to the joint BVA, BSAVA and BVZS policy statement
Fipronil (0.25% w/v spray)	3 ml/kg topically (lower end of the dose range); repeat as necessary at 4 weeks (See drug datasheet for more information)	Apply correct dose of spray to a gloved hand and then wipe over animal’s body, taking care to avoid risk of hypothermia
Ivermectin (50 µg (micrograms) per pipette)	Dose at 200–400 µg/kg topically: ◦ 50–100 g bodyweight = 6 drops ◦ 100–150 g bodyweight = 9 drops ◦ 150–200 g bodyweight = 12 drops ◦ 200–250 g bodyweight = 1 pipette ◦ 250–500 g bodyweight = 2 pipettes Repeat at 2 and 4 weeks as necessary. (See drug datasheet for more information)	Apply on the skin between the shoulder blades at the back of the neck
Permethrinh	50–100 g bodyweight = 2 drops 100–200 g bodyweight = 3 drops 200–300 g bodyweight = 4 drops 300–400 g bodyweight = 6 drops Repeat at 2 weeks as necessary (See drug datasheet for more information)	Apply on the skin between the shoulder blades at the back of the neck Do not use in animals <16 weeks of age
Toltrazuril	10 mg/kg p.o. q24h for 3 days, off for 3 days, on for 3 daysg	Note that the 2.5% solution has a very low pH and should be diluted with equal parts of both water and propylene glycol (i.e. 1:1:1); there is no need to dilute the 5% solution in this way
Miscellaneous:
Interferon omega	1 megaunit/kg s.c. q24h for 3 consecutive daysi 1 megaunit/squirrel or 2.5 megaunit/kg s.c.; repeat dose after 2–3 daysj	Has been reported to have been beneficial in the treatment of squirrelpox virus (SQPV) cases

NSAID(s) = non-steroidal anti-inflammatory drug(s)

References and further reading

a Nannarone S, Moretti G, Bellocchi F et al. (2020) A comparative study of intramuscular alfaxalone- or ketamine-based anaesthetic mixtures in Gray Squirrels undergoing gonadectomy: Clinical and Physiologic Findings. Animals (Basel) 10(8), 1402

b Richardson C and Flecknell P (2009) Rodents: anaesthesia and analgesia. BSAVA Manual of Rodents and Ferrets, ed. E Keeble and A Meredith, pp. 63–71. BSAVA Publications, Gloucester

cOrr HE (2002) Rats and mice. BSAVA Manual of Exotic Pets, 4th edition, ed. A Meredith and S Redrobe, pp. 13–25. BSAVA Publications, Gloucester

dSainsbury AW (2003) Squirrels. In: BSAVA Manual of Wildlife Casualties, 1st edition, ed. E Mullineaux, D Best and JE Cooper, pp. 66–74. BSAVA Publications, Gloucester

eFlecknell P (1996) Anaesthesia and analgesia for rodents and rabbits. Handbook of Rodent and Rabbit Medicine, ed. K Laber-Laird, MM Swindle and P Flecknell, pp. 219–238. Pergamon, Oxford

fMeredith A (2015) BSAVA Small Animal Formulary, 9th edition – Part B: Exotic Pets. BSAVA Publications, Gloucester

gCarpenter JW and Harms CA (2022) Exotic Animal Formulary, 6th edition. Elsevier, Oxford

hWilks K (2008) Red squirrels and the parapoxvirus. Veterinary Nursing Journal 23(10), 41–42

iRSNE (2011a) RSNE Advice Note – Squirrel poxvirus fact sheet for vets. Red Squirrels Northern England (RSNE), Carlisle

jV Butler, personal communication

Blackett T (2016) Squirrels. BSAVA Manual of Wildlife Casualties, 2nd edition, ed. E Mullineaux and E Keeble, pp. 137–151. BSAVA Publications, Gloucester

BSAVA Library www.bsavalibrary.com

BVA, BSAVA, BVZS joint policy statement: Responsible use of parasiticides https://www.bva.co.uk/take-action/our-policies/responsible-use-of-parasiticides-for-cats-and-dogs/

Red Squirrels Northern England www.rsne.org.uk