d with other rodents Usually Staphylococcus spp.
Bite wounds; primary skin infections possible.
Treatment: Trimethoprim-sulfamethoxazole, trimethoprim-sulfadiazine, or enrofloxacin. (Avoid antibiotics with predominantly gram-positive spectrum.)
Pododermatitis Guinea pigs Staphylococcus aureus.
Enlarged, edematous, and erythematous food pads, with crusting, hemorrhage, or ulceration. Advanced cases have a poor prognosis due to difficult treatment and occurrence of systemic amyloidosis from chronic infection.
Treatment: topical antibiotic rinses (diluted chlorhexidine or diluted povidone-iodine), systemic antibiotics (trimethoprim-sulfamethoxazole or trimethoprim-sulfadiazine at 30 mg/kg PO BID; or enrofloxacin 10 mg/kg PO BID), and soft, frequently-changed bedding.
Non-infected wounds may be encouraged to epithelialize by using BioDres or TegadermÔ wound dressings.
Lice Guinea pigs Direct observation of adults or nits or by acetate tape impression.
Treatment: Use pyrethrin or pyrethroid sprays (labeled safe for cats), or 2% lime-sulfur dips, or ivermectin (200 400 m g/kg SC every 10 14 days until there is no evidence of infestation).
Staphylococcal nasal dermatitis
Alopecia on the nose and muzzle and no other lesions. Caused by rubbing the cage or burrowing or excess secretion or accumulation of the harderian gland secretions.
Treatment: place pet in a smooth sided cage with soft bedding (shredded newspaper), decrease humidity (normal is 40 - 50%).
Staphylococcus spp. infection
Alopecia with erythema, oozing, crusting, scaling, abscessation, fistulation, or ulceration.
Treatment: Give trimethoprim-sulfamethoxazole or trimethoprim-sulfadiazine at 30 mg/kg PO BID; or enrofloxacin 10 mg/kg PO BID
Skin cancers Rare in all pet rodents Definitive diagnosis made by biopsy.
Signs: Solid tumors or alopecia.
Tumors are common. Rats develop tumors more often than do mice or other pet rodents.
Most common tumors seen:
Rats: mammary gland fibroadenomas
Mice: mammary adenocarcinomas
Guinea pigs: trichofolliculomas (a solitary lesion in the dorsal lumbar region with alopecic and crusted skin overlying the tumor; keratinous material or hemorrhagic exudate may come from a central pore); neoplasms of the lungs, reproductive tract, mammary glands, & hematopoietic system
Hamsters: nodal lymphosarcomas, adrenal cortical tumors, and uterine adenocarcinomas; rarely, cheek pouch neoplasia
Gerbils: squamous cell carcinomas, melanomas, and female reproductive tract neoplasms
Diagnosis of solid tumors: fine-needle aspiration & cytologic exam; excisional biopsy/surgical removal & histopathologic exam
Other diagnostic aids: blood tests, radiographic and/or sonogram examinations, biopsies, and post mortem examinations
Tumor removal is usually curative, but depends on the tumor type.
Respiratory problems are commonly noted by owners. Clinical symptoms range from mild nasal or ocular discharge to anorexia, lethargy, dyspnea, and increased respiratory sounds upon auscultation (dry or moist rales, wheezing).
Guinea pigs: Bordetella spp. and Streptococcus spp.
Rats and mice: Mycoplasma spp.
Other rodents: Streptococcus spp., Pasteurella spp., and Corynebacterium spp.
Other causes: viruses, heat stress, allergies, pregnancy toxemia (guinea pigs only), and irritation from bedding material
Diagnosis: history, clinical signs, and radiographic exam
Systemic antibiotics - Trimethoprim-sulfamethoxazole or trimethoprim-sulfadiazine at 30 mg/kg PO BID
Ophthalmic drops/ointments - Tetracycline, chloramphenicol, gentamicin
Added treatments for more severe cases (dyspnea, anorexia, lethargy):
Fluid therapy - Give a balanced electrolyte solution (lactated Ringers solution) at 10 ml/100g body weight/day for maintenance; use subcutaneous, intraperitoneal, or intraosseous (anesthetized patients only) routes.
Warm patient in incubator warming (< 80° F)
Give parenteral antibiotics: enrofloxacin 10 mg/kg SC BID
Supply oxygen therapy
Give supplemental vitamin C (50 100 mg/pet IM BID) to all sick guinea pigs
Advise owner that prognosis is guarded to poor with severe disease.
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