Morbidity and disease management in pet rats: a study of 375 cases

Abstract

Typical diseases are well described in pet rats, but their prevalence and management are largely unknown. During a six-month period, standardised records were obtained for 375 rats presenting in three French centres to determine the diagnoses made and the treatments prescribed. Rhinitis, healthy animal and mammary gland tumours accounted for the majority of diagnoses. The 10 most common diagnoses accounted for 66.9 per cent of all cases. Inappropriate environment was a risk factor for respiratory disease (P<0.001). Mean age of presentation of rats with respiratory disease was lower for rats living in non-appropriate environment (P=0.049). Twenty-two per cent of animals underwent surgery, with a significant difference according to sex because of the higher rate of mammary gland tumours in females (P=0.006). Tumourectomy, ovariohysterectomy or castration accounted for 70 per cent of all procedures. Training veterinarians on 10 clinical situations, 3 surgical procedures and 3 therapeutic classes would improve the management of most of the pet rats. An early visit to provide owners with all recommendations and information on appropriate maintenance, and one visit around 15 months of age to detect any mass at an early stage, could help to reduce respiratory disease and improve clinical outcomes.

Altered prolactin and androgen receptors expression in companion rat benign mammary tumours

“…Rats are among the five most common companion animals kept in the United States, 1,2 and mammary tumours are among the most common spontaneous tumours of companion rats, 1,3 with a similar prevalence to what is reported in Sprague Dawley laboratory rats 4 . Fibroadenomas are benign biphasic tumours with an epithelial and a stromal compartment and represent the majority of mammary tumours in rats.…”

“…Despite the frequency of mammary fibroadenomas, few studies evaluate the expression and role of hormone receptors in the pathogenesis of mammary gland tumorigenesis in rats 5 . Surgical excision of mammary tumours is the treatment of choice, 1,3 but additional mammary masses often emerge within a few months following excision which often lead to euthanasia or animal welfare issues 5 . In a retrospective study of companion rats, 75% (12/16) of the rats developed additional mammary masses 1 to 8 months postoperatively, with a median disease‐free survival of 4.5 months 5 .…”

Sonography of the pituitary gland in pet rats

“…study with post‐mortem MRI (the length was 3 mm, the height was 1.5 mm, and the width was 4.7 mm). We believe that our findings could help differentiate between normal and abnormal PG‐size pituitary gland abnormalities, such as neoplasia or hyperplasia, could thus be identified as antemortem 3 …”

“…Our study also lacked any subjects of advanced age (over 18 months). Since pituitary hyperplasia is more frequent in older rats, it is not possible to understand whether there is a difference in size between young and older subjects, as reported in the literature 3 . A second limitation of the study is the small number of rats which is not sufficient to be able to obtain a reference range of the dimensions of the PG.…”

“…1 The incidence of tumors in rats is 87% in selected populations older than 2 years of age. 1,2,3 Most reports of spontaneous tumors in rats are derived from laboratory populations, with few reports on the pet population. 4 The incidence and types of tumors vary by rat strain, age, sex, diet, calorie intake, and environment.…”