Infectious diseases of rabbits*

what are general considerations for infectious diseases of rabbits?*

• prey animals - hide signs of disease

• clinical signs can overlap and be non-specific

what type of virus is myxomatosis?

leporipoxvirus

how is myxomatosis trasnmitted in rabbits?

• biting arthropods - fleas, mosquitoes, Cheyletiella mites

• inhalation

• direct contact

which rabbits get severe disease from myxomatosis?

• European wild rabbits

• pet rabbits

(North American wild species and hares get mild disease)

what does clinical disease depend on for myxomatosis?

• the strain

• season (vectors life cycle)

• environment temp

• age (maternal antibodies for 4-5 weeks)

• immune function

• vaccination status

what are clinical signs of myxomatosis?

• eyelid thickening + purulent eye discharge

• nodules on ears, lips, nares, eyelids, external genitalia

• occasionally pneumonia signs

• infertility

• death by starvation or secondary infection

can myxomatosis be treated?

• no effective treatment

• euthanasia advised

• supportive care + antibiotics and strict isolation

what is the risk of rabbits surviving myxomatosis?

most die, but some can survive —> become carrier and shed disease later in life

how can we prevent myxomatosis?

• vaccination from 5 weeks of age

• yearly booster

• external parasite control

• avoid contact with wild rabbits

what type of virus is shope fibroma virus?

leporipoxvirus

what does shope fibroma virus cause?

self-limiting fibromas / fibromatosis

if rabbit is infected with shope fibroma virus, how does this affect immunity to myxomatosis?

get cross immunity for myxomatosis

what type of virus is shope papilloma virus?

papillomavirus (oncovirus)

what do we see with shope papilloma virus?

• horn like protrusions (more significant clinical disease than shope fibroma virus)

• becomes malignant squamous cell carcinoma in 25%

what is rabbit oral papillomavirus?

• another type of papillopmatosis

• benign wart like growths in oral mucosa

• no malignancy, self-limiting

what is ano-rectal papillomatosis?

• another form of papillomatosis

• not viral induced

• causes cauliflower masses that bleed easily

what type of virus is viral haemorrhagic disease?

calcivirus

what are the two strains of viral haemorrhagic disease (VHD)?

• VHD-1

• VHD-2 (possibly hypervigilant)

how is VHD transmitted?

• urine

• faeces

• aerosols

• biting insects

what are clinical signs of VHD?

• fever

• increased resp rate

• collapse, hypotension

• neurological signs

• haemorrhages

• VHD1 disease in rabbits > 4 weeks, mild disease if 6-8 weeks

• VHD2 non specific for age

• often don’t notice any clincial signs - appears as sudden death

how do diagnose VHD?

• gross pathology - severe necrotising hepatitis, enlarged spleen, haemorrhages

• histology

• PCR

can we treat VHD?

• VHD1 - no treatment, euthanasia reccomended, if young rabbit can survive infection

• VHD2 - if mild may survive, but no specific treatment

how can we prevent VHD?

• vaccination against VHD1 and 2, from 5 weeks of age

• yearly booster

what bacteria causes snuffles?

Pasteurella multocida

what is the pathogenicity of pasteurellosis?

• several strains

• primarily in immunosuppressed rabbits

• secondary pathogen in abscesses

• can avoid phagocytosis, complement and other host defence mechanisms

• endotoxin production

• adhesion and filaments help infect host’s cells

what are risk factors for pasteurellosis?

• overcrowding

• pregnancy / lactation

• poor husbandry

• nutritional deficiencies

• poor ventilation

• breed predispositions

what are clinical signs of pasteurellosis?

• rhinitis (sniffles)

• pneumonia

• genital infections

• wounds and abscesses

• dacryocystitis

• otitis media / interna

• malignant form

how do we diagnose pasteurellosis?

• culture and sensitivity - deep nasal swab performed under sedation / GA

• serology - doesnt indicate an active infection

• PCR

how can we manage pasteurellosis?

• reduce stress and overcrowding

• improve husbandry, increase ventilation

• avoid temperature fluctuations

• isolate symptomatic rabbits

• antibiotics based on C&S + supportive care + treatment of specific clinical signs

what bacteria causes rabbit syphilis?

Treponema paraluiscuniculi

how is Treponema transmitted?

• sexual transmission

• vertical transmission

what does Treponema cause?

crusty nodules that can ulcerate - on the vulva / prepuce and lips and nostrils

how can we diagnose Treponema?

histo and special silver stains needed for definitive diagnosis

what are differentials for treponema?

• myxomatosis

• ano-rectal papillomatosis

how do we treat Treponema?

penicillin SC weekly

what bacteria causes Tularaemia?

Francisella tularensis

what is Tularaemia?

• highly fatal disease affecting rabbits, hares, rodents, livestock, dogs, cats, horses, etc.

• only in USA

• zoonotic

what are clinical signs of Tularaemia?

• sudden death

• fever

• weakness

• skin ulcers

• abscesses

• lymphadenopathy

what can cause diarrhoea in rabbits?

• bacterial enteritis

  • Tyzzer’s disease

  • Yersinia pseudotuberculosis

  • Clostridial enterotoxaemia

  • Salmonella

  • E. coli

  • Campylobacter

• Coccidiosis

• diet change

• dysbiosis

• neoplasia

• iatrogenic

what rabbits are mostly affected with Tyzzer’s disease?

young rabbits (6-12 weeks)

what bacteria causes Tyzzer’s disease

Clostridium piliforme

how do rabbits contract Tyzzer’s disease?

• faeco-oral transmission

• frequently secondary to stress

what does Tyzzer’s disease cause in acute phase and chronic phase?

• acute - diarrhoea, sudden death

• chronic - intestinal fibrosis/stenosis, liver necrosis

what are the two forms of pseudo TB?

• septic - rapdily fatal

• non-septic - abscess, weight loss, diarrhoea

what rabbits are affectly by pseudo TB?

older rabbits

how is pseudo TB transmitted?

faeco-oral route

what is a significant consideration with Pseudo TB?

zoonosis

what species of clostridium cause clostridial enterotoxaemia?

• Clostridium spiriforme

• C. difficile

• C. perfringens

what are the main causes of Clostridial enterotoxaemia?

• diets rich in starch - causes caecum overload

• stress

• antibiotics - especially if given oral

  • B-lactams - penicillins, amox-clav, cephalosporins, etc.

  • Clindamycin

  • lincomycin

  • streptomycin

  • erythromycin

what should we look at when examining rabbits with diarrhoea?

• weight

• dehydration status

• temperature

• gut sounds

• blood glucose

• faecal samples for testing

how should we manage rabbits with diarrhoea?

• fluid therapy SC or IV

• diet management - high fibre, low sugar/starch, may need syringe feeding

• antibiotics - fluoroquinolones or metronidazole

• analgesia

• cholestyramine - if suspect enterotoxaemia

• maropitant

• probiotics - but not sure how effective

what are risk factors for coccidiosis?

• being in groups

• young rabbits

what are clinical signs of intestinal coccidiosis?

diarrhoea (sometimes with blood) + weight loss

what Eimeria spp. causes hepatic coccidiosis?

Eimeria stiedae

what are clinical signs of hepatic coccidiosis?

• diarrhoea and weight loss

• hepatomegaly and jaundice

• higher mortality than intestinal coccidiosis

how do we treat coccidiosis?

• TMP + Sulfas

• Toltrazuril

• supportive care + improve husbandry + diet management

what is the difference in recovery for intestinal vs hepatic coccidiosis?

• intestinal coccidiosis - rabbits that recover become immune

• hepatic coccidiosis - chronic / permanent changes

what internal parasites do we see in rabbits?

• coccidiosis is main one, other are not common

• oxyurids (pinworms) - Passalurus ambiguus

• Tapeworms

what rabbits are more at risk for oxyurids and tapeworms?

• outdoor rabbits

• larger groups

(but still uncommon)

what Tapeworm species affect rabbits?

• Echinococcus granulosus

• Cysticercus (Taenia) pisiformis - peritoneal cavity, liver

• Coenurus (Taenia) serialis - SC tissues

what external parasites affect rabbits?

• fleas - Spilopsyllus cuniculi (rabbit flea), also affected by cat and dog fleas

• lice - Haemodipsus ventricosus

• mites

  • ear mites - Psoroptes caniculis

  • skin mites - Cheyletiella parasitovorax

  • fur mites - Leporacarus gibbus

how do we diagnose external parasites?

• skin scrapes

• skin strips

what are mites frequently secondary to in rabbits?

• inability to groom - e.g. dental disease, arthritis, spinal disease

• immunosuppression

how do we treat external parasites?

• imidaclopride

• selamectin

• moxidectin

• do not use fipronil

what causes flystrike?

maggots of Lucilla spp and Calliphora spp flies

what is the most commonly affected area for flystrike?

tail base and perineum

what are risk factors for flystrike?

• outdoor rabbits

• high temperatures

• soiled skin - e.g. rabbits with diarrhoea or pu/pd

• overweight

• difficulty grooming - arthritis, spinal disease

• uneaten caecotrophs

how quickly does flystrike progress?

very quickly - progression is 3-4 days

how do we manage flystrike?

• euthanasia in severe cases

• remove maggots

  • clip affected area and manually remove maggots, under sedation

  • ivermectin SC - causes maggot paralysis

  • bathe areas with dilute iodine solution

  • dry affected areas with blow dryer

• analgesia - meloxicam ± buprenorphine

• supportive care - fluids, gut motility stimulants, antibiotics if secondary infection

how can we prevent flystrike in rabbits?

• cyromazine

• F10 dpray (cypermethrin)

• inspect rabbits twice daily during risk season

• clip any mats

• provide good husbandry, hygiene and diet

• regular health checks