OBJECTIVE To describe the prevalence, histologic characteristics, concomitant abnormalities, and outcomes for various types of mammary gland tumors in companion rats (Rattus norvegicus). DESIGN Retrospective case series. ANIMALS 100 client-owned rats. PROCEDURES Medical records of companion rats that had an SC mass and were examined at a veterinary teaching hospital between 1990 and 2015 were reviewed. Information regarding the signalment, age at mass detection, reproductive sterilization status, histologic diagnosis of the SC mass, location of the initial and all subsequent SC masses, treatments administered, and clinical outcomes was extracted from each record and summarized. RESULTS 105 SC masses were initially detected in 100 rats. The most prevalent SC mass identified was mammary gland fibroadenoma (56/105 [53%]), followed by mammary gland carcinoma (13/105 [12%]). Overall, 26 of 105 (25%) masses were malignant. Sexually intact males were more likely to have nonmammary SC tumors than sexually intact females. In rats receiving no adjunctive treatment after excision of a mammary gland fibroadenoma (n = 16), a second fibroadenoma was detected 1 to 8 months after initial excision, at a median of 4.5 months after surgery. A concomitant pituitary gland tumor was identified in most rats with mammary gland fibroadenoma (21/28 [75%]) and other types of mammary gland tumors (10/17 [59%]). Fourteen of 35 (40%) rats with mammary gland fibroadenoma had concomitant reproductive tract abnormalities. CONCLUSION AND CLINICAL RELEVANCE Results suggested that, like other species, companion rats with SC masses should undergo a thorough diagnostic workup that includes histologic examination of the excised mass.

Veterinarians caring for companion animals may encounter microsporidia in various host species, and diagnosis and treatment of these fungal organisms can be particularly challenging. Fourteen microsporidial species have been reported to infect humans and some of them are zoonotic; however, to date, direct zoonotic transmission is difficult to document versus transit through the digestive tract. In this context, summarizing information available about microsporidiosis of companion exotic animals is relevant due to the proximity of these animals to their owners. Diagnostic modalities and therapeutic challenges are reviewed by taxa. Further studies are needed to better assess risks associated with animal microsporidia for immunosuppressed owners and to improve detection and treatment of infected companion animals.

Many animals under human care are kept indoors to prevent infectious diseases vectored by wildlife, facilitate environment control, or due to the lifestyle of their owners. However, ultraviolet radiation has documented effects on animal vision, vitamin synthesis, immunity, behavior, psychogenic disorders and on their environment. Ultraviolet-emitting lights are commercially available and the documentation of their effect on indoor-housed animals is increasing. This article reviews published information about ultraviolet effects in vertebrate animals from veterinary and ethological perspectives, and techniques used to assess ultraviolet exposure across animal taxa.