II. Dermatophytosis
III. Fleas and Lice
IV. Mites
V. Myxoma Virus
VI. Pasteurellosis
VII. Rabbit Oral Papilloma Virus
VIII. Rabbit (Shope) Fibroma Virus
IX. Rabbit (Shope) Papilloma Virus
X. Sore Hocks (Ulcerative Pododermatitis)
XI. Staphylococcus Infections
XII. Venereal Spirochetosis (Rabbit Syphilis, Vent Disease, Cuniculosis)
Cuterebrid flies are also known as rodent and rabbit warble flies.
Cuterebriasis occurs most frequently in wild rabbits, but may occur in
domestic rabbits housed outdoors. Incidence peaks in the summer and
late fall. Single or multiple large subcutaneous swellings containing
encysted larvae with a fistula in the center are the characteristic lesions
(left photo). When the larval fly is ready to pupate, it leaves the
swelling and drops to the ground (right photo). Secondary bacterial
infections may complicate the disease. These lesions are treated
by removing the larva (without crushing it) and flushing the wound, or
by surgical resection of the wound. Prevention of infestation includes
moving the cage indoors, or by surrounding the hutch with screen to prevent
fly exposure.
. 
A. Etiology: Trichophyton mentagrophytes is an opportunistic, ubiquitous fungal soil organism.
B. Incidence: There is high incidence of the carrier state, with low incidence of disease.
C. Clinical Signs: A crusty, pruritic, patchy alopecia on
the head which spreads to the paws and other parts of the body is typical
(see photo). Secondary bacterial infections are common. 
D. Diagnosis: Diagnosis is based on clinical signs, scraping and identification of spores on hair shaft or mycelia within hair shaft, and culture on Sabaraud or DTM agars.
E. Treatment: Topical treatment with a fungicide (Tresiderm, Iodine, Conofite cream) or griseofulvin (25 mg/kg in aqueous suspension or 0.375 gm powdered form/lb food for 14 days) has been successful. Topical 10% chlorox solution is also effective. Griseofulvin therapy should be used with caution in breeding herds, as the incidence of teratogenesis is associated with treatment.
F. Control: Disinfect cage and nest boxes with 10% bleach solution. There is a possibility of transmission of infection to people handling the rabbits, so gloves should be worn when treating the rabbits. Ventilation should be improved to decrease the relative humidity, and all filters, water pads, curtains/blinds or other materials used to control the air temperature should be replaced weekly to prevent collection of fungus spores.
Public Health Significance: People handling rabbits with T. mentagrophytes induced lesions have developed dermatophytosis.Pasteurellosis
Rabbits are commonly infested with Ctenocephalides sp., especially C. felis. The infestation may be asymptomatic, but may induce mild pruritis and alopecia. Rabbits can be dusted and sprayed with pyrethrin products. Do not use the product Frontline as rabbit deaths have been associated with its use. The environment should be treated to control this parasitism.
Haemodipsus ventricosis (Blood Sucking Louse). The anapleurid louse is rarely found on domestic rabbits. Weakness, anemia, ruffled fur and pruritis (secondary dermatitis) are common signs of infection. The pelt can be examined with a dissecting microscope or a hand lens. Nits, as well as the adult anopleurid louse (head narrower than body), may be found on the hair. Rabbits should be treated with pyrethrin products, silica gel acaricides or ivermectin (0.2 to 0.4 mg/kg SubQ) at 10 day intervals for 2 treatments. This louse spends its entire life cycle on the rabbit with little horizontal transmission. Isolation is an effective means of control while treating the infected rabbit.
A. Psoroptes cuniculi - ear mite
1. Etiology: This nonburrowing, obligate mite has a high incidence of occurrence in meat, laboratory and pet rabbits. The life cycle is completed in around 21 days.
2. Clinical Signs: Scratching at ears with hind feet and the presence of crusty exudate in the pinnas with an underlying moist dermatitis are characteristic. The parasites do not cause otitis media since they do not penetrate the tympanic membrane.
3. Diagnosis: Mites can be observed with an otoscope or
on a mineral oil preparation of the crusty exudate. The mites are
oval-shaped with well-developed legs, pointed pedicles, and bell-shaped
suckers on the end of pedicles. 
4. Treatment: Crusts are gently removed from the canal. Mineral oil with or without acaricide in the ear canal will kill the mites. Ivermectin at doses of 0.2 to 0.4 mg/kg SC will eliminate most infections with a single treatment. Antibiotic cream can be used if the ear is infected.
5. Control: Infected animals should be isolated. During treatment, the cage should be disinfected.
B. Cheyletiella parasitovorax - fur mite
1. Etiology: C. parasitovorax is a small, noninvasive mite, with a low to moderate incidence of infection.
2. Clinical Signs: Partial alopecia of dorsal trunk or scapular region with a fine, grey scale on erythematous skin results from infestation. (The mite is often called "walking dandruff.") There is some pruritis.
3. Diagnosis: Examination of the pelt will reveal small white mites
with piercing chelicerae and large curved palpal
hooks, and the eggs are attached to hair shafts.
4. Treatment: Rabbits can be dusted or sprayed with pyrethrin preparations or silica gel acaricides, with repeat treatments at 10 day intervals. Ivermectin at 0.2 to 0.4 mg/kg SC should also be effective.
5. Control: Infested rabbits should be isolated during treatments. Cleaning and spraying the rabbit's environment with insecticidal preparations aids in decontamination of the fomites.
Public Health Significance: This parasite can cause a transient pruritic rash in hypersensitized people, especially children.
C. Listrophorus gibbus - fur mite
1. Etiology: L. gibbus is a small, nonburrowing mite present at low to moderate incidence in domestic rabbits. It is an obligate parasite, completing all stages of the life cycle on the host.
2. Clinical Signs: This mite is currently considered non-pathogenic and is found primarily on the back and abdomen.
3. Diagnosis: The hair shafts can be examined under a dissecting
microscope or with hand lens for the characteristic brown mite or its nits.
4. Control: Isolate infected animals. Topical acaricides
and ivermectin as described for cheyletiella are thought to be effective
in treatment.
A. Etiology: Myxomatosis is caused by any one of several strains of myxoma virus, a member of the leporipoxvirus group. Virulence of the different strains ranges from a mortality incidence of 99% in European rabbits to less than 30%. Incidence is high in endemic areas in the Pacific coastal states.
B. Transmission: The principal mode of transmission is via arthropod vectors (mosquitoes, fleas, flies, gnats). Transmission may also occur by contact with infected material from ocular discharges or oozing skin lesions of infected rabbits, contaminated spines of thistles, and the claws of predatory birds. Virus-infected skin nodules on wild rabbits, Syvilagus sp., are reservoirs of the agent.
C. Symptoms: In domestic rabbits, the clinical disease picture is largely predicated by the strain of virus involved as well as genetic resistance of the breed of rabbit.
California Strain of Virus: In the peracute form, rabbits die
within a week of exposure showing slight edema of the eyelids and
depression immediately prior to death. With the acute form in which
rabbits survive for 1 to 2 weeks, symptoms are edema of the eyelids resulting
in a droopy appearance of the eye; inflammation and edema around the anal,
genital, oral, and nasal orifices; skin hemorrhages; and convulsions.
A nodular lesion develops at the site of inoculation with both forms, but
it is not a clearly defined tumor.
Standard Laboratory Strain of Virus: This strain induces a mean survival time of 11 days. Around 3 to 4 days post inoculation, a primary tumor becomes evident, and generalized tumors are seen on the 6th or 7th day. At this time, a mucopurulent nasal discharge and pronounced edema of the eyes and base of the ears are seen. By day 10, hard lumps cover much of the body.
European Strain of Virus: This strain is characterized by rapid proliferation of large lumps by day 7. The lumps may break open by day 10 and release a serous discharge. Lumps may occur on any area of the body. There is also pronounced edema of the face and anal regions, seropurulent discharge from eyes and nose, and considerable skin congestion.
D. Pathology: The most prominent gross lesions are skin tumors
and pronounced cutaneous and subcutaneous edema. Skin hemorrhages
and subserosal petechial and ecchymotic hemorrhages in the stomach and
intestines may be observed. Various degrees of congestion will occur
in the visceral organs depending on the severity of the disease.
Skin
tumors result from an initial proliferation of undifferentiated mesenchymal
cells in the dermis which become large stellate cells termed myxoma cells.
These cells lie in a homogeneous matrix of mucinous material. Necrosis
can be observed in the center of this area. Epidermal cells overlying
the tumor may appear normal in early stages of the tumor proliferation,
or they may show hyperplasia or degeneration in later stages. Intracytoplasmic
inclusions (arrows) are observed most commonly in cells of the prickle-cell
layer of the epidermis, and in the stellate myxomatous cells.
F. Diagnosis: A diagnosis can be made from the clinical and pathological picture, virus isolation, and PCR amplification of viral sequences from tissue specimens. Serological tests including fluorescent antibody techniques, plaque-neutralization, and ELISA have been developed but are not commercially available.
G. Control: Control is achieved through vector control and adequate screening of the rabbitry, by quarantine of new animals, and isolation of all sick animals. A common practice, once a death from myxomatosis is diagnosed, is to cull all rabbits whose body temperature exceeds 104oF in an attempt to remove animals incubating the virus before shedding occurs. A vaccine was developed but has not been used as the vaccine caused clinical myxomatosis in some vaccinated rabbits.
VI. Pasteurellosis
A. Etiology: Pasteurella multocida is a small, gram-negative,
nonspore-forming bipolar rod.
B. Transmission: Transmission occurs by direct contact, aerosol, venereal, and hematogenous routes. Incidence of infection and disease is high (probably > 90%). Many rabbits are asymptomatic carriers. The incidence of bacterial carriage is no different in antibiotic-treated rabbits.
C. Disease Forms: Upper respiratory disease ("snuffles"), pneumonia, otitis media, pyometra, orchitis, subcutaneous abscesses, conjunctivitis and septicemia are manifestations of P. multocida infection.
1. Snuffles - This is the most common manifestation of pasteurellosis.
Clinical signs characteristically include serous to mucopurulent nasal
exudate with sneezing and coughing. Exudate may be seen on the medial
aspect of the forepaws. Signs may subside temporarily only to recur
throughout life. Lesions include reddened mucosa in acute infections,
thickened mucosa in chronic infections, and exudate in nasal cavity and
paranasal sinuses. Antibiotic therapy (see Table 1) usually causes
abatement of clinical signs. The prognosis for disease improvement
or remission is good, however there is a good chance of recurrence. 
2. Enzootic Pneumonia - Affected rabbits frequently die
acutely with no signs (especially young rabbits); anorexia and depression
may be observed. Acute pneumonia lesions include red-grey foci of
consolidation of the cranioventral lung lobes with or without hemorrhage.
Chronic pneumonia is characterized by generalized consolidation, encapsulated
abscesses, fibrinopurulent or mucopurulent pleuritis and pyothorax.
If the pneumonia is recognized early, aggressive antibiotic therapy may
be of some value. The prognosis for all cases of pneumonia is poor. 
3. Otitis Media - Usually there are no clinical signs.
Torticollis will occur if the function of the internal ear is compromised,
either by direct bacterial invasion or by the damaging effects of the bacterial
toxins. Nervous signs and incoordination are observed if the bacteria
extends to the meninges. Creamy, white exudate in middle ear is found either
uni- or bilaterally. When treated with antibiotics at the first indication
of a head tilt, rabbits with otitis media may improve or stabilize.
In rabbits with severe torticollis, NSAID or corticosteroid therapy may
be indicated. Bulla osteotomies and lavage of the tympanic bullae
has proven to be a fruitless approach to treatment. The torticollis
may progress in spite of antibiotic therapy, so the prognosis is guarded. 
4. Genital Infections - Venereal or hematogenous transmission
may occur. Affected rabbits may have a vaginal discharge which may
be serous to mucopurulent and/or a history of infertility. The uterus
can be palpably enlarged with pyometra. Acute infection of the uterus
is characterized by slightly dilated horns filled with grey exudate.
In chronic infections the uterine horns are greatly dilated with purulent
exudate, and are fragile. In affected bucks, one or both testicles
may be enlarged, tender, firm and may contain abscesses. The health
of affected rabbits can be salvaged by surgical removal of diseased tissues
coupled with antibiotic therapy. The prognosis for recovery after
surgery is good. 
5. Abscesses - Contaminated wounds and septicemia are common routes for abscess development in a variety of locations, but especially in the subcutis. The presence of subcutaneous swellings which are filled with creamy exudate and may have draining fistulous tracts is typical of Pasteurella abscesses. Treatments include sedation of the rabbit prior to lancing and flushing superficial abscesses t.i.d. with Betadine or chlorhexidine. Systemic antibiotic therapy should be provided for 1 week. If the infections persist, surgical resection may be required.
6. Conjunctivitis - Signs include epiphora with blephorospasm,
eyelids closed by excessive mucopurulent exudate and facial staining.
Reddened conjuctiva with serous to mucopurulent adherent exudate are found.
Often there is inflammation and eventual stenosis of the nasolacrimal duct,
resulting in chronic epiphora and hair loss. The use of antibiotic
ophthalmic ointments will improve most cases. Occasionally, the nasolacrimal
duct may need to be flushed to remove inspissated purulent material. 
7. Septicemia - Septicemic rabbits usually die acutely; however, one may see pneumonia or infertility prior to death. Diffuse congestion and petechiation of thoracic and abdominal viscera as well as abscesses in viscera (kidneys, liver, lungs) may be seen on necropsy.
D. Predisposing Factors: Onset of clinical disease is often associated with some underlying stressor, such as a marked change in environmental temperature or humidity, poor ventilation, poor sanitation, and overcrowding. Physiologic conditions that also predispose to disease is age (very young or very old), pregnancy, nutritional state, and genetics. Some rabbit stocks are genetically hardier, and can carry Pasteurella throughout life without developing clinical disease.
E. Diagnosis: Tentative diagnosis of pasteurellosis is based on clinical signs and gross necropsy findings of a mucopurulent exudate associated with inflamed body parts such as the respiratory tract, subcutis, middle ears, and reproductive tract. A presumptive diagnosis may be reached by making a smear or scraping from the affected area and staining with a gram stain. With torticollis, radiographs of the tympanic bulla may disclose the presence of exudate or bony reaction (increased density in the bulla). Definitive diagnosis requires isolation of the bacteria by culturing the affected site(s).
F. Treatment: Most Pasteurella isolates are sensitive to penicillin. Only sulfaquinoxaline and tetracycline have known withdrawal times and can be used for rabbits raised for slaughter. Short term use of certain oral antibiotics, such as ampicillin or amoxicillin, or prolonged systemic antibiotic therapy with any drug may upset the cecal bacterial flora. If anorexia or diarrhea occurs during therapy, stop treatment immediately. Dietary supplementation with high fiber foods, such as alfalfa cubes or high fiber pelleted diets, or with yogurt containing live Lactobacillus cultures may reduce intestinal upsets.
TABLE 1: Antibiotics Commonly Dispensed for Rabbits
Enrofloxicin 2.5 to 5 mg/kg b.i.d. for 5 to 7 days (oral and injectable)
Procaine penicillin 40 to 60,000 IU/kg body weight IM s.i.d. for 3 to 10 days
Sulfaquinoxaline 0.256 gm/50 gm feed for 30 days or 226 gm/ton of feed
Tetracycline 300 mg/liter of water for 7 days, or 5 mg/kg q.i.d. for 7 days
G. Control: The best control for pasteurellosis is good husbandry techniques and culling of rabbits with clinical disease. Since most all rabbits carry Pasteurella multocida in the nasal cavity, management measures are aimed at controlling the clinical disease expression. The rabbitry must have good ventilation, low ammonia levels, and low humidity to decrease incidence of this disease. In a breeding colony situation, all infected rabbits with clinical disease should be culled for many reasons. (In spite of antibiotic therapy, the chance of disease recurrence is high. Rabbits with clinical signs shed large numbers of organisms into the environment. The best way to improve the genetic hardiness is to remove breeders with clinical disease.) Clean automatic waterers and cages in which diseased rabbits were housed and then spray with 1% bleach solution to kill residual bacteria. (Bleach will eventually damage galvanized caging, so alternative disinfectants can be used.) All new arrivals should be quarantined prior to introduction into the rabbitry. If possible, weanling rabbits should be raised separately from the breeding colony.
VII. Rabbit Oral Papilloma Virus
A. Etiology: A member of the papovavirus group, this virus is the only member of the papovavirus group having the domestic rabbit as its natural host. There is moderate incidence of disease.
B. Transmission: Spread is by direct contact of oral secretions containing sloughed epithelial cells from the oral warts. Infection occurs in the abraded epithelium of the tongue.
C. Clinical Signs: This is a benign disease characterized by numerous whitish growths on the underside of the tongue, oral cavity epithelium or gingiva. These later become pedunculated and ultimately ulcerate. The growths regress when the rabbit becomes immune.
D. Pathology: A typical papilloma with verrucous epidermal hyperplasia with rete peg formation and hyperkeratosis and dermal fibroplasia has been described. Intraepithelial viral inclusion bodies are not usually seen on microscopic examination of tumors.
E. Diagnosis: The gross lesions are diagnostic.
F. Control: No control measures to prevent exposure are known. Recovered rabbits are resistant to reinfection.
VIII. Rabbit (Shope) Fibroma Virus
A. Etiology: Fibroma virus is a member of the leporipoxvirus group and is closely related to myxoma virus. The virus has widespread incidence in both domestic and wild rabbit populations. Few cases of virus-induced fibromas have been diagnosed in rabbits in Missouri although the majority of cases are reported from the western and southwestern United States.
B. Transmission: The natural transmission cycle is not known although arthropod vector transmission is likely.
C. Clinical Signs: Tumors occur on the legs or feet, on the muzzle,
and around the eyes. The tumors are subcutaneous and not attached
to underlying tissue. Metastases from the original tumor do not occur.
The infected adult rabbit remains clinically normal otherwise. Tumors
will typically regress after a period of months. Spontaneous and
experimental infections of neonatal domestic rabbits, however, has produced
cutaneous and visceral tumors. 
D. Pathology: The earliest lesion is slight thickening of the subcutaneous tissue followed by development of clearly demarcated soft tissue swellings which are evident on day 6 post inoculation. Tumors increase in size until day 12. They persist for months before regressing. The earliest microscopic lesion is an acute inflammatory reaction followed by localized fibroblastic proliferation. Proliferation continues until a distinct tumor is formed consisting of spindle-shaped and polygonal connective tissue cells with abundant cytoplasm. Intracytoplasmic inclusions are present in stellate cells, and less commonly or rarely in the epidermal cells. Degeneration of the epidermis overlying the tumor may result from pressure ischemia. This leads to necrosis and sloughing of the epithelium.
F. Diagnosis: Clinical signs and lesion morphology are primary diagnostic tools.
G. Control: This is not considered to be an important problem in domestic rabbits. In outdoor rabbitries, vector control is advised.
IX. Rabbit (Shope) Papilloma Virus
A. Etiology: A member of the papovavirus group. This disease is seen most frequently in cottontail rabbits of the Midwest with outbreaks in domestic rabbits. Incidence of disease is low.
B. Transmission: Arthropod vector transmission of the natural disease has been demonstrated. The mosquito is thought to be the main vector in transmission from feral to domestic rabbits.
C. Clinical Signs: Horny warts are found on the eyelids and ears. The growths are well keratinized, and the upper surface is irregular and split. The growths are easily scratched or knocked off. These sites later heal without complication.
D. Pathology: The tumor has the typical appearance of a papilloma with elongated rete pegs of epithelium surrounding central cores of connective tissue. A mild inflammatory cell infiltrate is normally found in the dermal layers underlying the tumor. Failure of the lesion to resolve may lead to development of squamous cell carcinoma.
E. Diagnosis: Clinical signs and histological examination are the basis for diagnosis.
F. Control: Control of the arthropod vectors will eliminate the introduction and spread of disease. Tumors that fail to spontaneously resolve in 30 days should be removed surgically to prevent dedifferentiation into neoplasia.
X. Sore Hocks (Ulcerative Pododermatitis)
Sore hocks occur because of pressure necrosis of the skin from
bearing a heavy body weight on a hard or wire surface. There is genetic
predisposition in breeds such as the Rex which have poorly furred footpads
and rounded metacarpal bones . Common findings are circumscribed
ulcers over the metatarsus and metacarpus, covered by a scab. There
may be purulent exudate under the scab. Severely affected rabbits
may be anorexic, debilitated, and die. Use soft dry bedding, a resting
board in wire cages, and topical zinc and iodine ointments or an antibiotic
ointment if secondarily infected. Use systemic antibiotics if abscesses
are present or if the rabbit is debilitated. Cull affected animals
and do not use for breeding stock. Decrease environmental humidity.
Caution: Fecal pellets need to be brushed off the resting board daily
to prevent ingestion of infective parasite ova/oocysts. 
A. Etiology: Staphylococcus aureus is a Gram-positive, hemolytic, coagulase-positive coccus.
B. Transmission: Aerosol and direct contact (organism present in oral cavity of non-clinical carriers) are primary routes of infection. Incidence of infection is moderate, but the incidence of disease is low.
C. Clinical Signs: There is a wide range of clinical disease forms. S. aureus may cause suppurative infection in any organ or any site. Subcutaneous abscesses, mastitis with abscess formation, dermatitis, upper respiratory infection with mucopurulent nasal discharge, and septicemia with depression, anorexia, fever, and death have been reported. Of these disease syndromes, abscess formation and mastitis are most commonly reported.
1. Abscesses - Abscesses may occur subcutaneously or in the viscera. At necropsy thick-walled abscesses filled with purulent exudate are found. Diffuse congestion and petechiation of viscera may be seen in septicemic animals. Clinicopathologic lesions are similar to those of pasteurellosis. Presumptive diagnosis may be made by making a smear and gram stain of the exudate. Culture and antibiotic sensitivities are needed for a definitive diagnosis and choice of treatment. If the organism is sensitive to penicillin, 40,000 IU/kg procaine penicillin, IM s.i.d., for 3 to 5 days may be effective. Subcutaneous abscesses should be lanced and flushed with germicidal solution along with administration of systemic antibiotics. Surgical extirpation may be necessary to resolve chronic abscesses. To decrease the incidence of abscesses, the cages must be kept clean, fighting animals separated, and clinically ill rabbits isolated.XII. Venereal Spirochetosis (Rabbit Syphilis, Vent Disease, Cuniculosis)2. Mastitis - Mastitis or blue breast disease is commonly found in herds with intensified production. Infection of gland occurs through trauma to the teat, ascending infection through the teat canal, or secondary to septicemia. Mastitis occurs just after kindling. The mammary glands are swollen, usually not discolored, and may develop abscesses. Frequently there is loss of function of the affected gland and rarely the doe may die. Bunnies may die because of infected milk or not grow as well because of decreased function of the gland. Therapy includes hot packing the affected gland, systemic antibiotic therapy, and transfer of bunnies to a healthy lactating doe. To prevent mastitis, keep nest boxes clean and dry. Limit feed to the doe just prior to kindling to prevent excessive milk production and stagnation. Cull all affected does.
A. Etiology: Treponema paraluis cuniculi is a spiral-shaped bacterium related to the human syphilis organism, Treponema pallidum.
B. Transmission: Genital transmission is most common.
C. Clinical Signs: Cutaneous Infections - Erythema
of mucous membrane of external genitalia which progresses to focal, raised,
crusty ulcerations is the most common sign. Lesions can occur on
the perineal area and face due to auto-inoculation. As ulcerations
heal, a dry scaly condition follows. Spontaneous regression usually
occurs in several weeks. The bacteria causes only superficial, cutaneous
pathology. There may be popliteal and inguinal lymph node enlargement.
Mild or subclinical disease is common. Reluctance to breed and decreased
reproductive efficiency may occur. 
D. Diagnosis: Serological tests to identify antibody in actively or recently infected rabbits include the hemagglutination test, Rapid Plasma Reagin (RPR), or fluorescent treponema antigen preparation. (FTA). T. paraluis cuniculi may be found in histosections with silver stain or with darkfield microscopy of fresh specimens.
E. Treatment: A regimen of procaine penicillin, 40,000 IU IM s.i.d. for 3 to 5 days is curative. Once the spirochete is eliminated, serum antibody drops gradually to undetectable levels.
F. Control: If spirochetosis is a herd problem, treat the entire
herd. Do not breed infected animals. If animals are for meat
production, do not treat weanlings or fryers; treat only breeding stock.
Maintain a closed breeding colony or quarantine and medicate new arrivals.
Recovered animals can be used as breeding stock without danger of transmitting
infection.
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