Successful sanitation of an EDIM-infected mouse colony by breeding cessation

Abstract

Despite decreasing prevalence, rotavirus infections still rank among the most important viral infections in colonies of laboratory mice. Although the disease is characterized by low mortality and a relatively short and mild clinical period, the infection has the potential to alter the outcome of experiments substantially. For animal facilities, it is therefore essential to eradicate the virus. Here we report a successful sanitation of a rotavirus-infected mouse colony in an animal facility. Despite a high ratio of transgenic and partially immunodeficient strains, a permanent eradication of the virus was achieved by euthanasia of highly susceptible mice, a prolonged breeding cessation in areas containing immunocompromised mice and a strict hygienic management. The management of a rotavirus infection reported here is a feasible and inexpensive opportunity for sanitation that benefits from maintaining most of the animal population, even in today's mouse colonies comprising mainly transgenic mice with unknown or compromised immune status.

Viral Infections of Laboratory Mice

“…They are most prominent at the apices of villi, where rotaviruses infect and replicate within epithelial cells; the large intestinal surface mucosa may also be affected. Though inflammation is minimal, the lamina propria may be oedematous, lymphatics may be dilated and mild leukocytic infiltration in the large intestinal mucosa and submucosa has been observed in a recent outbreak of disease [36,393]. Hydropic change of villous epithelial cells is the hallmark finding of acute disease.…”

“…Embryo transfer or caesarean derivation followed by barrier maintenance is recommended for rederivation of breeding stocks [8]. In immunocompetent mice in which infection is effectively cleared, a breeding suspension strategy for 8-10 weeks combined with excellent sanitation, filter tops and conscientious serological testing of offspring and sentinel mice has also been reported to be effective, and prolongation of breeding cessation up to 12 weeks resolved infection even in immunocompromised mice [393].…”

“…Vacuolation and cytoplasmatic swelling of villar epithelial cells in the small intestine (B) and mixed infiltration of leucocytes in mucosa and submucosa (C) of the colon. From Held et al[393], used with permission from RSM Press.…”

Contaminated Shipping Materials Identified as the Source of Rotaviral Infection of Exported Mice

“…Mouse rotavirus (MRV) is a group A rotavirus that replicates in the villus epithelial cells of the small intestine. 2,6,9,20,24 It has also been shown to undergo extraintestinal replication as well. 8 Epizootic diarrhea of infant mice virus (EDIM) is commonly used as a generic name for all mouse rotaviruses.…”

“…15,22,[24][25][26] All ages of mice can become infected, but clinical signs typically occur only in infant mice younger than 2 wk and in pups from nonimmune dams. 2,9,13,14,20,24 Because maternal antibodies protect pups, clinical signs of EDIM tend to disappear once the virus becomes enzootic in a colony. 9,20,24 Common clinical signs of EDIM include diarrhea, abdominal bloating, fecal staining, and delayed growth.…”