Exotics Flashcards
What is IgY and what is its relationship to IgG?
IgY is the major circulating antibody found in birds and reptiles and is the counterpart to mammalian IgG.
IgY has the same general structure as mammalian IgG, with two heavy chains (“nu” chains at ~67-70 kDa) and two light chains (at 22-30 kDa).
Feather Loss: Abnormal moults
It is important to realize that moulting is a normal process, but the number per year (1/ year in many species, 2/year in many migratory species, q2 years or poorly defined in psittacines) and the type (progressive vs non-progressive). However, a number of external factors can adversely influence moulting, resulting in poor feather quality and/or abnormal pigmentation:
- Nutritional deficits: inadequate protein, decreased amino acids (lysine, choline, methionine, cysteine, cysteine); vitamin A [especially on all seed diets] or beta carotene, riboflavin
- Stress/fear
- Reduction of light period: especially if after prolonged periods of light may initiate moult
- Ectoparasites: see below
- Hypothyroidism: results in retardation of feather growth. Normal T4 levels in birds are lower than mammals.
Feather Loss: Feather destructive behavior
It may be difficult to differentiate a bird that is truly pruritic due to organic causes from a bird that is feather-picking due to behavioral problems. While the presentation is most commonly due to behavioral problems, more ‘organic’ causes should always be investigated. It is most commonly a problem with psittacines among pet birds. It is important to recall that virtually any disease that causes a change/diminishment in feather quality may lead to the bird trying to remove the affected feathers.
• A UK study showed that 39.4% of 137 African grey parrots and 42.4% of 92 cockatoos exhibited feather-plucking behavior at some point in their lifetime.
• Increasing sleep hours, length of ownership correlated with FDB in African greys.
• Pet shop origin, cage location against >1 wall and >1 vacation per year by
owners correlated with FDB in cockatoos
Behavioral causes of feather loss
a. These birds are prey species. If they are placed next to a window where they can see crows, hawks, etc., they may compensate for their inability to ‘escape’ with feather- picking
b. These birds are gregarious. A solitary bird, without stimulation (‘bored’), may compensate with feather-picking.
c. These birds in the wild spend approximately 50% of their time foraging. Having food readily available in the cage may again lead to a ‘bored’ bird. Having the bird ‘work’ for its food by putting it in various slightly difficult to open receptacles may be helpful.
d. Attention seeking – the owner may be giving unintentional positive reinforcement by interacting with the bird when it performs ‘bad behavior’ i.e., feather-picking. Ignoring the bird may be helpful – it is beyond the scope of this lecture to talk about behavioral modification training.
e. Separation anxiety. Medication such as clomipramine (0.5-1.0 mg/kg per os bid or fluoxetine 1-2 mg/kg per os bid) may help but must be combined with behavioral modification training.
f. Overcrowding and social stress may lead to feather-plucking and stress over territorial rights. A dominant bird may pluck a subordinate.
g. Sexual frustration has been thought to be an important cause of feather-picking in cockatoos, lovebirds, and African greys. Hand reared birds may become sexually active as early as 6 months.
h. Trauma- any externalor internal injury may be picked at by the bird.
Organic causes of feather loss
- Ectoparasites: these can cause pruritus and discomfort.
- Endoparasites
- Allergies
- Environmental
- Hypothyroidism
- Liver disease
- Bacterial dermatitis
- Fungal infections
- Viral infections
- Genetic abnormalities
- Neoplasia
- Heavy metal toxicity
Harpyrhynchid spp.
Several of these affect psittacines, H serini mite affects canaries. They attach to feather bases and in severe cases cause hyperkeratotic epidermal cysts.
Dermanyssus (red mites)
feed on the bird at night but are free-living and breed in the cage or environment during the day. A white sheet over the cage helps diagnosis in the morning by visualizing the mites. These mites can attack mammals including humans. Most commonly a parasite of chickens.
Feather mites
these usually do cause problems unless there is a heavy infestation, in which case poor husbandry should be suspected. Budgerigars have at least two species: Protolichus lunula on the wing and tail feathers and Dubininia melopsittaci on smaller body feathers.
Mallophaga (biting lice)
lice (various species) are species specific and the life cycle is completely on the host. Only Mallophaga (biting lice) affect birds. They are usually easy to see as they travel through the plumage. Louse infestation is a sign of poor husbandry.
Treatments for ectoparasites in birds
Fipronyl spray (Frontline®) or selamectin spot-on (Revolution® [Stronghold® in Europe]) have all been recommended. If using a spray it is important NOT to soak the bird. Lately, the isoxazolines (afoxolaner, fluralaner) have been shown to be useful and safe in treating mites and lice)
Points to remember: Imidacloprid (Advantage®) is toxic to birds; ivermectin should not be given to finches.
Pruritic ectoparasites in birds
1) Lice (various species)
2) Knemidocoptes spp (sometimes spelled Cnemidocoptes) mites
3) Dermanyssus (red mites)
4) Feather mites
5) Harpyrhynchid spp.
Organic causes of pruritus in birds: endoparasites
Giardia infection has been linked to pruritus in budgerigars, lovebirds, and cockatiels
Organic causes of pruritus in birds: allergies
while there is good evidence of an atopic-dermatitis-type condition in some birds (especially large psittacines) based on intradermal testing, effective and safe treatment has not been well substantiated.
Organic causes of pruritus in birds: environmental
1) excess tobacco smoke, aerosols, building dust, low humidity (central heating turned up) may all lead to pruritus or poor father quality which resulting in brittle feathers which break as the bird plucks them. Many psittacines evolved in rain forest conditions, and a dry environment may lead to poor quality feathers that the bird will try to remove. These birds may benefit from water misting.
Organic causes of pruritus in birds: liver disease
example Chlamydophila infection. This can cause many clinical signs, but skin-wise may cause pruritus with subsequent feather removal.
Organic causes of pruritus in birds: neoplasia
Birds may pluck over the site of a skin cancer
Organic causes of pruritus in birds: bacterial
olliculitis/pulpitis has been reported especially in the developing feather. Staphylococcus aureus and Staphylococcus intermedius have been isolated from birds – the frequency of these organisms causing infection and subsequent pruritus is not known. Recent studies suggest that the uropygial gland secretions may have broad anti-microbial properties.
Organic causes of pruritus in birds: viral
Circovirus (aka Psittacine Beak and Feather disease – PBFD)
Polyoma virus.
Organic causes of pruritus in birds: fungal
these may be underdiagnosed. Candida has been reported especially in gallinaceous birds in the vet area and in pet birds around the head – feather follicle involvement shows white crusting around the affected follicles. Dermatophytes may cause patchy feather loss especially on the head, neck and breast. Malassezia has been implicate as a cause of pruritus by some authors.
Point to remember: Itraconazole may be toxic to Grey parrots
Organic causes of pruritus in birds: genetic
feather dusters’ and ‘straw feather’ affect budgerigars. These interesting names describe the visual appearance of the affected birds. Feather cysts occur in certain lines of canaries.
Organic causes of pruritus in birds: heavy metal toxicity
primarily lead, zinc, copper or iron, generally from new cages or toys, may cause abnormal feathers to develop that the bird tries to remove.
Circovirus (aka Psittacine Beak and Feather disease – PBFD).
A DNA virus which can remain in the environment for up to one year. Several strains: PBFD I is found in many species while PBFD is found in lorikeets. More common in young bird and in Old World psittacines. Several presentations:
a. Peracute (usually no skin signs)
b. acute(occurs during first feather formation and leads to rapid development of dystrophic feathers);
c. chronic (birds 6 months to 3 years old, leads to dystrophic feathers, lack of powder down, pulp cavity hemorrhage, feather fracture, hyperkeratosis, beak overgrowth or fracture, oral ulcerations. As the disease is immunosuppressive, secondary infections are common).
Diagnosis is via PCR on the blood or pulpy feathers. Treatment is supportive care. The disease in lorikeets may be less severe and full recovery may be possible.
Polyoma virus
DNA (Papovavirus) which affects all psitacines and passerines (watch for finches with beak overgrowth). Clinical signs in budgerigars include neonatal death, reduced down and contour feathers. If the neonates survive, they lose tail and flight feathers and are known as ‘French moulters’, ‘runners’, ‘creepers’ or ‘crawlers.
PBFD (circovirus) can cause similar signs and is probably more common. This feather loss will eventually resolve but the birds are carriers. The disease is much less common in other psittacines and typically only affects very young birds. In passerines acute death is the most common presentation, but beak and feather abnormalities may also be present. Diagnosis is by PCR, but the psittacine PCR does not work in finches.
List 2 cutaneous neoplasias in birds
Poxvirus
Papilloma virus
Poxvirus
A DNA virus. Pox viral infections can affect the oral cavity, the trachea, and can cause a septicemia. In the skin, the virus causes nodules, papules, or vesicles. This cutaneous form is most common in songbirds and raptors affecting the feet, eyes and face. Canaries and finches, in addition to the skin lesions, will often develop severe pulmonary complications. Lovebird pox causes lesions on the face, oral and nasal cavities, axilla, shoulder and abdomen – lesions are discolored, pruritic and often infected secondarily with bacteria. The form affecting Amazon parrots is self-limiting for skin lesions but often fatal with the diptheric (oral cavity and trachea) form. Diagnosis is through histology or impressions smears demonstrating the intra-cytoplasmic eosinophilic inclusion (Bollinger) bodies. As pox virus is spread via insect vectors, control of pests is important.
Papilloma virus
Yet another DNA virus, this one causes benign epithelial tumors, often affecting the cloaca, oral cavity or skin. Usual treatment is surgical removal if practical. Spontaneous remission has been described.
List nutritional deficits in birds that cause feather loss
Inadequate protein, decreased amino acids (lysine, choline, methionine, cysteine, cysteine); vitamin A [especially on all seed diets] or beta carotene, riboflavin
Dysecdysis
is the term given to abnormal shedding of the skin. It is important to remember that dysecdysis is not a disease per se; rather it is be a sign of other problems including poor husbandry, ectoparasitism (such as the snake mite, Ophionyssus natricis), systemic disease, too cold an ambient temperature, improper humidity, poor nutrition, and attempts to pull off the shedding skin by well-meaning but misinformed owners. Retained skin around the digits of lizards can lead to ischemia with subsequent necrosis, necessitating amputation of the digits.
Ophionyssus natricis
the snake mite, is a common parasite of snakes and lizards. Pruritus, dysecdysis, snakes staying in water are typical signs.
This mite may serve as a vector of Aeromonas. Previously reported treatments are: ivermectin (0.2 mg/kg at 2 week intervals), ivermectin spray (5mg/l) on animals and environment weekly for 5 times. Remember ivermectin is TOXIC to chelonians. Moxidectin has also been recommended. Another method to treat snakes is to spray a towel with fipronil spray (Frontline®) then wipe the snake with the towel. Pyrethroids and organophosphates should be avoided. Cages should be disinfected with bleach diluted 1/20 with water, then rinsed well. A recent report describes successful treatment of this mite with afoxalaner at 2mg/kg orally, once.
This mite should be searched for and the infestation treated on reptiles introduced in the collection as well as on fomites such as branches. Quarantine and treatment of new animals should be followed. The parasite can be difficult to completely eliminate from collections. Transmission of the mite to humans has been reported. Similar mites, in the same genus (ex: Ophionyssus lacertinus) are found in lizards.
Ophionyssus serves as a vector for what disease?
This mite may serve as a vector of Aeromonas. Aeromonas spp. are Gram-negative, frementative, and oxidase-positive bacteria. They have been associated with disease in some lizards, in particular the Aeromonas hydrophila species.
Ivermectin is TOXIC to ______.
chelonians (turtles and tortoises)
Ophionyssus lacertinus
lizard mite
Chrysosporium anamorph of Nannizziopsis vriesii
‘yellow-fungus disease’
Is devastating reptile collections (primarily lizards) all over the world. CANV often may be misdiagnosed as a Trichophyton species. Bearded dragons and chameleons predominated early reports.
Demonstrating the organism on both culture and histopathology, plus (ideally) by DNA sequencing, may be limited by owner finances or difficulties in identification or isolation. Itraconazole is occasionally effective; posaconazole and voriconazole are probably more effective. Terbinafine has also been suggested as a treatment: it is possible that combining this drug with an azole may be more effective than either alone. This disease often becomes systemic. There are a number of fungi in the Chrysosporium genus that can adversely affect reptiles and other animals, including people.
CANV often may be misdiagnosed as a what fungal species?
Trichophyton species
Bacterial infections in reptiles
As poikilotherms (‘cold blooded’), reptiles’ immune systems are ‘slower’ to respond to infections. This is especially obvious in abscesses, which are very common, and in the long length of time some reptiles need to be on antibiotics (months). Abscesses are often best treated by removal, rather than lancing and draining, as in reptiles they are not liquid but rather granulomatous in consistency. In regards to antibiotics different species have different dosage regimens (see Table I, and Mitchell reference). Petechiae, especially in chelonians, may signify sepsis, as may a ventral ‘flush’ in snakes. Dermatophilus congolensis has been reported in bearded dragons and is zoonotic.
Dermatophilus congolensis has been reported in what reptile species and is it zoonotic?
Dermatophilus congolensis has been reported in bearded dragons and is zoonotic
Burns in reptiles
Reptiles do not seem to be able to realize when a focal source of heat (example: a ‘heat rock’ or a lamp) is so hot that they will be burned. The reason for this is unknown, but heat rocks should not be used. Other sources of burns are incandescent lights, contact with any hot substrate, or temperatures above 50°C. Clinically, burns appear as areas of erythema, (± edema), exudation, crusts ,and ultimately as necrosis with sloughing of the skin. Secondary bacterial infection is very common. Treatment consists of placing the patient in a container without sand or any substrate (so as to avoid these sticking to the wound areas or topical treatments) antibiotic(silversulfadiazine) cream, and (per Dr. Patrick Bourdeau’s recommendation) topical vitamin A ointment. Turtles should be bathed only 3-4 times weekly (except soft-shelled species) and most importantly change the responsible heating device to a safer one.
Shell problems in chelonians:
these often relate to
1) too high a humidity for tortoises
2) bacterial or occasionally fungal infections, causing (a) shell necrosis (b) ulcerative shell disease (Vibrionaceae: Beneckea chitinivora) (c) Septicemic Cutaneous Ulcerative Disease (SCUD - Citrobacter freundii)
3) poor nutrition (low-calcium diet)
Treatment depends on causation. Antibiotics, both topical and systemic, cleaning of enclosure, and balancing the diet may all be indicated.
Septicemic Cutaneous Ulcerative Disease (SCUD) is caused by what organism?
The bacteria Citrobacter freundii is often responsible for SCUD, though there are other bacteria that have been isolated in this condition.
Emydomyces testavorans
a newly described keratinophilic fungal organism which is associated with ulcerative skin and shell disease and may be underdiagnosed. Keratin inclusion cysts are a common feature of infection.
It is an onygenalean fungus that has been isolated from shell lesions of freshwater aquatic turtles.
Blister disease in snakes and lizards
The most frequent are inappropriate humidity (for example, green tree pythons may need as > 95% relative humidity, whereas sand boas need <40%), various secondary bacterial and fungal pathogens, and concurrent systemic disease. Vesicles and pustules, which evolve into ulcers and necrosis, are found primarily on the ventrum. Treatment depends on the underlying disease process, but generally includes lancing the blister, applying antibiotic ointment and/or chlorhexidine to the affected areas, and removing the reptile to another terrarium without contaminated substrate.
Nutritional skin diseases in reptiles
Besides imbalances in calcium, deficiencies of vitamin A (usually young chelonians – palpebral edema, aural abscesses, sometimes dyskeratosis), vitamin C (chelonians and snakes - stomatitis), iodine (perhaps caused by ingestion of certain plants, affects chelonians and lizards, presents as goiters) have been reported. Steatitis in snakes, is caused by a diet too high in fats (fish, obese rats) which leads to unsaturated fatty acid oxidation and a secondary vitamin E deficiency. This presents as a yellowish color of the skin, nodules, inflammation, and eventually secondary bacterial infections and sloughing.
In addition to these deficiencies, reptiles may also get hypervitaminosis A, sometimes caused by iatrogenic administration, which can cause sloughing of the skin. In addition, the excess vitamin A causes dry, exudative, thickened skin.
Treatment of all of the above diseases obviously depends on correcting the dietary imbalances. Remember that nutrition in reptiles is not monolithic: Different reptiles are omnivores, herbivores, or carnivores. Some switch from one to the other as they mature. All snakes are carnivores. Some recommended dosages: Vitamin C 10-20mg/kg q24h per os or subcutaneous; Vitamin A 40 IU/100g bw per os for 2-3 weeks
Otitis is most common in what reptile species?
Usually presents as otitis media and is most comon in chelonians, rare in lizards. Clinical signs are to nodular lesions (abscesses) on lateral head. Various bacteria are implicated, especially Proteus morganii.
Treatment is surgical, with lancing and removal of pus, packing with antibiotic cream, and systemic antibiotics.
In chelonians aural abscess have been associated with hypovitaminosis
What bacterial species is most commonly associated with otitis media in chelonians?
Proteus morganii
List pruritic parasites in rabbits
Psoroptes cuniculi
Ctenocephalides sp.
Spilopsyllus cuniculi
Sarcoptes scabeii
rodents, rabbits, others (Ornithonyssus bacoti).
List pruritic parasites in G.pigs?
Trixacarus caviae
Chirodiscoides caviae
List pruritic parasites in hamsters
Notoedres muris
List pruritic parasites in rats and mice
Myobia musculi, Myocoptes musculinus, Radfordia ensifera, Notoedres muris, Liponyssus bacoti, Polyplax spinulosa, Polyplax serrata
List pruritic parasites in rodents and rabbits
Ornithonyssus bacoti
Psoroptes cuniculi
(rabbit ear mite)
This parasite causes otitis externa and rarely otitis media which can result in neurologic signs.
Rabbits will present with head shaking, pruritus of ears and head and/or ear dropping (this may be the initial sign). Pinna and canals will be erythematous and will have a thick crust which is often red-brown in color.
Other parts of the body may be rarely affected. Do NOT attempt removal of crusts as this is quite painful !! Use systemic anti-parasiticides, as discussed below. Sarcoptic mange has also been reported in pet rabbits and especially in rabbit colonies.
Trixacarus caviae
(guinea pig sarcoptid mite)
T. caviae infestation should be considered as the FIRST differential for any pruritic guinea pig.
Do NOT rule it out if the cage-mate does not show any clinical signs. Convulsions resembling seizures can be seen in guinea pigs due to the intense pruritus and debilitation experienced by some affected animals.
Notoedres muris
hamster and rat sarcoptid mite
Notoedric acariasis in hamsters affects mainly the ears, face, genitalia and tail.
The diagnosis can be made by distribution and characterization of the clinical signs and by performing skin scrapings. Rats affected by notoedric acariasis resemble hamsters clinically, except that they sometimes present with nasal ‘horns’.
Frequently the mite can be visualized when performing a skin scrape of this nasal hyperkeratotic lesion.
Lice
Seen in small numbers in rabbits and rodents. Large numbers may indicate an infestation with another skin parasite, or an underlying systemic disease (hypovitaminosis C in Guinea pigs, for example). Polyplax serrata (mice) and Polyplax spinulosa (rats) may serve as vectors for Mycoplasma (Haemobartonella) muris, Encephalitozoon cuniculi, and Eperythrozoon coccoides.
Polyplax serrata (mice) and Polyplax spinulosa (rats) may serve as vectors for what 3 diseases?
Mycoplasma (Haemobartonella) muris, Encephalitozoon cuniculi, and Eperythrozoon coccoides
Treatment of epidermal mites and lice
Ivermectin
Selamectin
Imidacloprid/moxidectin
Imidacloprid (Advantage, Bayer)
Ivermectin in rodents
0.2 to 0.4 mg/kg q 2 weeks for 2 to 3 treatments PO or SQ. However, ivermectin should not be administered orally to guinea pigs due to difficulties with GI absorption.9 Specifically for Notoedres muris in hamsters and rats: ivermectin 0.5 mg/kg administered q1-2wks PO, SQ or in the form of a pour-on solution for at least 8 weeks is recommended.8,10 In rabbits, ivermectin has been used to treat Cheyletiella infestations in doses ranging from 0.2-2.1 mg/kg SQ q11 days x 3 or 0.6-2.7 mg/kg PO q10 days x 3.11
Selemectin treatment in rodents
Selamectin (Revolution, Zoetis)
Imidacloprid/moxidectin in rodents
This has also been shown to be effective for ear mites applied 3 times, 30 days apart,14 as well as effective against Ornithonyssus bacoti. 14a A single subcutaneous dose of eprinomectin at 200 or 300 microg/kg was able to eliminate P. cuniculi infection in rabbits15, although topical protocols with this drug have not been as effective.15a This same product was effective in treating guinea pigs infested with Gliricola porcelli with only one application.
Imidacloprid treatment in rodents
hould be effective in treating lice (but not mite) infestation, however, again, dosages have not been well-researched.
Do NOT use ________ in rabbits (or hedgehogs) as its use has been associated with fatalities.
fipronil (Frontline/Frontline Plus, Merial) there may be adverse effects from the spray form in hedgehogs, which may be due to this species’ predisposition for respiratory problems as well as their tendency to roll up in a ball (putting the nares in close proximity to the sprayed skin).
Topical lime sulfur in rodents
This is an option to manage lice in rats and mice at 1:32 dilution with water.
Fleas in rodents
Domestic rabbits are often exposed to fleas Ctenocephalides sp. when they share the household with a dog or cat. In pet rabbits housed outside or exposed to wild rabbits, various flea species may be found including the rabbit flea Spilopsyllus cuniculi. Infestations of S. cuniculi are common in rabbit colonies. The life cycle of this flea is controlled by the hormonal cycle of the host, which explains the sudden proliferation seen on pregnant does and young rabbits. S. cuniculi is also important as a vector for myxomatosis. S. cuniculi most often bites on the pinnae and face, and may also bite cats and dogs. Pruritus is variable in flea infestation in rabbits, but may be severe. Imidacloprid (Advantage®: Bayer), a topical adulticide, has been shown to be safe and effective in flea control in rabbits, and is licensed for this purpose in the United Kingdom.
What is the name of the ‘rabbit flea’?
The rabbit flea is Spilopsyllus cuniculi. Infestations of S. cuniculi are common in rabbit colonies.
Internal neoplasia in rats
s not a well-documented cause of pruritus but the author has seen a few pruritic rats with internal neoplasia, although the association between the pruritus and neoplasia was not proven, i.e. the neoplasia was not removed/treated to determine if the pruritus would resolve.
Causes of alopecia without pruritus in rabbits
Causes of this clinical presentation include: dermatophytes, barbering, shedding, Demodex sp and endocrinopathies.
Rodent dermatophytosis
The usual dermatophyte species affecting rabbits and rodents are Trichophyton mentagrophytes, Microsporum canis, and M. gypseum. T. mentagrophytes is the most common in laboratory colonies, pet shops, etc, but M. canis may be more common in house pets. Clinical signs besides alopecia may include scales, crusts and erythema. Trichophyton porcellae has been identified in Guinea pigs.
What is the common dermatophyte species found on guinea pigs?
Trichophyton porcellae
Treatment of dermatophytosis in rodents
Itraconazole 5-10 mg/kg daily, for 1 month, although the drug is probably safe for up to 3 months. Terbinafine 10mg/kg for 2 to 6 weeks, making a suspension of the terbinafine in water or syrup. It may be more efficacious than the azoles.16a
Griseofulvin – 15 to 25 mg/kg PO for 4 weeks. Avoid its use in pregnant animals (teratogenic).
Lime sulfur topical 1:32 dilution with water 2-3 times weekly – can be used as sole treatment or adjunctive.
Enilconazole (Imaveral, Janssen – not available in USA) 2 times weekly is effective, however, rabbits and rodents are frequent groomers, and thus may ingest too much of the medication.
Clipping is not recommended due to difficulties and stress. The environment should be disinfected (discard bedding, wash cages in lime sulfur, etc.).
Treatment of dermatophytosis in rodents
Itraconazole 5-10 mg/kg daily, for 1 month, although the drug is probably safe for up to 3 months. Terbinafine 10mg/kg for 2 to 6 weeks, making a suspension of the terbinafine in water or syrup. It may be more efficacious than the azoles.
Griseofulvin – 15 to 25 mg/kg PO for 4 weeks. Avoid its use in pregnant animals (teratogenic).
Lime sulfur topical 1:32 dilution with water 2-3 times weekly – can be used as sole treatment or adjunctive.
Enilconazole (Imaveral, Janssen – not available in USA) 2 times weekly is effective, however, rabbits and rodents are frequent groomers, and thus may ingest too much of the medication.
Clipping is not recommended due to difficulties and stress. The environment should be disinfected (discard bedding, wash cages in lime sulfur, etc.).
Barbering in guinea pigs (when guinea pigs chew each other’s hair) is often associated with a lack of what in their diet?
fiber
Define ‘fur slip’
“Fur slip” in chinchilla – When frightened or stressed this species will shed tufts of hair (fur). It may take 3 to 5 months for hair to regrow.
What are the two species of Demodex found on Syrian hamsters?
This is most common in Syrian hamsters (Mesocricetus auratus) which have two species:
Demodex aurati – a long mite that lives in the hair follicle
Demodex criceti – a short mite that lives on/in the stratum corneum (more pruritic)
Demodex aurati
long mite that lives in the hair follicle of Syrian hamsters
Demodex criceti
a short mite that lives on/in the stratum corneum (more pruritic) of Syrian hamsters
Treatment of demodicosis in rodents
Ivermectin at 0.3 mg/kg SQ every 7 to 10 days or PO every 24 hours has been reported as effective.7 Treat until resolved and look for underlying diseases. Topical lime sulfur (1:32 dilution with water, twice weekly for 6 treatments) may be effective against the stratum corneum mite, D. criceti. There is one report of the topical use of 0.017% coumaphos (!) in the treatment of an unidentified Demodex species in a hamster.20 A recent report documents effectiveness of fluralaner against D aurati and D criceti in a golden hamster, at a dose of 25mg/kg, repeated in 60 days.
Endocrine alopecia is most commonly seen in what two species of rodents?
hamsters and guinea pigs.
Hyperadrenocorticism in rodents
Most common in hamsters, both pituitary dependent and adrenal tumor forms have been noted. Besides alopecia, skin hyperpigmentation, polyuria, polydypsia and polyphagia can be seen. Consistently effective treatment has not been well described.
A recent report documents this disease in a guinea pig, using salivary cortisol levels before and after ACTH administration, as well as successful treatment with trilostane at 2-4 mg per day.
Cystic ovaries in rodents
Most common in guinea pigs and associated with hyperestrogenism. Alopecia when present affects the flanks and is symmetrical and bilateral. Enlarged abdomen is a common sign. Age: 18 months to 5 years. Ovariohysterectomy is the preferred method of treatment.6 The surgery is not easy, due to the position of the ovaries and the relatively large GI tract. The following have been reported as medical treatments.
The following have been reported as medical treatments for cystic ovaries in guinea pigs?
Human Chorionic Gonadotropin:
Drug most commonly used for this condition
Dose: 1000 IU/guinea pig IM, repeated in 7-10 days (can be a large amount IM)
Stimulates an antibody response – makes subsequent doses potentially less effect + could cause allergic reaction with repeated use
GnRH:
Does not stimulate an immune response
Dose: 25 μg/guinea pig every 2 weeks for 2 injections
Volume less than Human Chorionic Gonadotropin
Commerically available form – Cystorelin®, Merial
Alopecia areata has been reported in what species of rodent?
Guinea pig
Causes of scaling and crusting dermatoses in rodents include:
Cheyletiella sp mites Venereal spirochetosis (rabbit syphilis) Hypovitaminosis C (guinea pig) sebaceous adenitis cutaneous lymphoma thymoma
Cheyletiella sp
(non-burrowing mites): Cheyletiellosis in rabbits is a very common cause of mild to severe scaly dermatosis. It is zoonotic and contagious to other animal species such as dogs and cats. Diagnosis is by finding mites on skin scrapings or acetate tape preparations. In a recent article from South Korea,Cheyletiella parasitovorax and Leporacarus gibbus (another, less common, fur
mite of rabbits),were found in 80 and 6, respectively, of 140 rabbits. Clinical signs of pruritus and scaling were observed in 17 of 80 and 76 of 80 infested rabbits, respectively.21cBoth these mites can cause dermatitis in humans.21d Treatment is selamectin as per treatment for ear mites (Psoroptes cuniculi). Lime sulfur dips (1:32dilution with water) 3 to 4 weekly dips are also effective, but messy and cumbersome in rabbits.
Treponema paraluiscuniculi
(formerly, Treponema cuniculi) is the organism causing venereal spirochetosis (rabbit syphilis). Clinical signs include crusts, erythema, edema, papules, vesicles, ulcers and proliferative lesions localized to the face and perineum. In one study, lesions were found most frequently around the nose followed by the genitalia, lips, eyelids, and anus. Sneezing was observed in 33% of cases with nasal lesions.22 In cases of maternally acquired infection, lesions could be initially found mainly on the face. Lesions are painful but not pruritic. The disease may be associated with metritis, abortion and neonatal death. Rabbit syphilis is NOT zoonotic.
Diagnosis is by microscopic visualization of T. cuniculi from skin scrapes on dark field microscopy, or special silver stains to demonstrate the organisms on biopsy. Additionally, the serologic tests used to diagnose syphilis in humans can be used.
Treatment:
Penicillin G at 40,000 to 80,000 IU/kg SC, weekly for 3 treatments. It is very important to monitor for signs of associated antibiotic enterotoxemia. Treat all in-contact rabbits.2,3,23 Chloramphenicol has been used successfully at a dosage of 55mg/kg q 12 h for 4 weeks. Another treatment is azithromycin 30 mg/kg/day given orally once or twice daily for 15 days; effectiveness in a large number of rabbits has not yet been reported, but this dose seems to be effective in experimental situations.
Sebaceous adenitis
has been reported in domestic rabbits as a cause of alopecia and non-pruritic scaly dermatosis.25 Diagnosis is by biopsy. The author is unaware of a favorable response reported to retinoids or glucocorticoids in the small number of rabbits treated. One report showed sebaceous adenitis and thymoma in the same rabbit.26 A similar presentation was seen in a rabbit with hepatopatits.27 Histopathology showed a cell-poor interface dermatitis (lymphocytic infiltration and apoptotic cells in basal layer of epidermis), absence of sebaceous glands and lymphocytic mural folliculitis.27 A case report documents a rabbit with sebaceous adenitis that was successfully treated with a combination of cyclosporine and a supplement of medium-chain triglycerides.27a Another case report showed better success by adding topical application of a shampoo, spray and spot-on containing the ceramide precursor phyosphingosine.27b
Cutaneous lymphoma
as been reported in hamsters, rabbits, mice, a guinea pig, and gerbils.28-30c It presents with severe alopecia, erythema and scaling. Prognosis is poor. As noted above, there is one report of a hamster having both demodicosis (with D. aurati) and cutaneous lymphoma.17 An early report in rabbits noted a T-cell origin of the lymphocytes invading the epidermis29, while a recent review of 25 cutaneous lymphomas in European pet rabbits classified the tumors as diffuse large B cell lymphomas, with 11 tumors exhibiting a T cell-rich B cell subtype.
Thymoma
One report describes 4 rabbits with confirmed mediastinal neoplasms, 2 thymomas 1 thymic lymphoma, 1 unknown. All rabbits presented with multifocal alopecia, erythema, follicular casts and scaling .Histology of the skin showed orthokeratosis, lymphocytic exocytosis, lymphocytic mural and interface folliculitis, and absent sebaceous glands, similar to some previous reports of sebaceous adenitis in this species.
Causes of nodular dermatoses in rodents
infectious/ulcerative pododermatitis
myxomatosis
mouse pox
trichofolliculoma
Nodules were the most common lesion seen in _____ in one report
hamsters
In hamsters, multiple trichofolliculomas have been associated with what virus?
polyoma virus
The most common subcutaneous nodule in companion rats was what tumor type?
mammary gland fibroadenoma
Additionally, a Zymbal gland (auditory sebaceous gland) carcinoma was reported as presenting as otitis externa in a pet rat.
Pododermatitis
(“Sore Hocks”) has been reported in rabbits and guinea pigs, and noted in rats. It was the most common skin disease noted in two retrospective case series
Pododermatitis in rabbits
Ulcerative pododermatitis is a chronic ulcerative granulomatous dermatitis of the metatarsal area seen in mainly in overweight inactive rabbits kept on wet bedding, grid floors, rough cages and/or unsanitary conditions. Hereditary factors are also thought to be involved and Rex rabbits are particularly affected as they lack protective guard hairs.
Lesions are bilateral, in the plantar aspect of metatarsal area with a progression of lesions typified by erythema, hyperkeratosis, crusts, pus, necrosis, osteomyelitis and septicemia. The treatment is difficult and based on correction of predisposing conditions, surgical drainage, topical antimicrobials, surgical dressings, and systemic antibiotics (based on culture and sensitivity)
In a recent article investigating pododermatitis in pet rabbits, there was no statistical correlation between body condition score and the presence of pododermatitis, but there was a statistically significant predilection in rabbits greater than 12 months of age, females, and neutered rabbits of either sex.
Why are Rex rabbits more affected with pododermatitis compared to other breeds?
Rex rabbits are particularly affected as they lack protective guard hairs.
What microorganism most commonly associated with pododermatitis secondary infections?
The secondary infectious agent most commonly present is Staphylococcus aureus
What is botryomycosis?
A rare chronic pyogranulomatous infection reported to be caused by several bacteria, has been reported in two pet rabbits.
Pododermatitis in Guinea pigs
Ulcerative pododermatitis is relatively common in guinea pigs. As in rabbits, S aureus is generally isolated, although Corynebacterium pyogenes may also be found. Obesity, poor hygiene, hypovitaminosis C, and wire flooring are all predisposing factors. Lesions are bilateral, on the plantar aspects of the metacarpal and metatarsal areas with a progression of erythema, hyperkeratosis, pus, necrosis, osteomyelitis and septicemia. Treatment involves topical antiseptics (silver sulfadiazine or mupirocin may be helpful) and systemic antibiotic therapy (enrofloxacin as noted above) and bandaging, plus addressing the underlying cause. However, treatment is often unsuccessful, and systemic amyloidosis often occurs due to the chronic infection
Myxomatosis
caused by a myxoma virus of the pox virus group, which is transmitted by various arthropod vectors, or through physical transport of the virus. New World rabbits are very resistant to this disease, but Old World rabbits are extremely susceptible (and pet rabbits are Old World rabbits). There are various strains of this virus. Clinical signs in peracute and acute cases are edema of the head, ears, eyelids and genitalia and milky oculonasal discharge. Firm non-pruritic and erythematous nodules (myxomas) are usually associated with less virulent strains and develop at the site of infection.
Lethargy, fever and anorexia can be present. Morbidity and mortality are high in pet rabbits, approaching 100%. The incubation period can range from 8 to 21 days. The diagnosis is by the clinical signs, typical microscopic lesions and virus isolation. Supportive treatment, vector control, and a vaccine (not commercially available in the USA) may be offered/discussed with the owner; the prognosis is grave
