Prevalence of 1.47% in Australasia amongst mice submitted for health monitoring to our laboratory, assessed by wet prep and faecal flotation methods
Dependent on - environmental load, gender (males tend to have a higher load), age (young animals tend to have a higher load), strain, and immune status
Significance limited to - decreased weight gain, behavioral changes, and altered immune responses
Nude mice (and other immunodeficient mice) have an increased susceptibility to develop heavy infestations and rarely mucosal invasion in the colon
Interference with research:
Syphacia spp. and A. tetraptera - may increase host humoral response to nonparasitic antigenic stimuli
S. obvelata - may be associated with termination of the tolerance state and induction of eosinophilic autoimmune oophoritis
Syphacia spp. - has accelerated hepatic monooxygenase system development
S. muris - have impaired transport of water, sodium, and chloride in rat intestines
Parasitic oxyurids – usually non- or mildly pathogenic in animals with normal immune systems
Syphacia spp. larvae and adults are primarily colonized in the caecum and anterior colon. Females lay adhesive-coated eggs on the perianal skin - infective 5-20 hours after release.
A. tetraptera larvae hatch in the caecum and then primarily colonize the crypts of Lieberkühn of the proximal colon. Eggs are deposited in the distal colon, excreted in the faeces, and become infective 5-8 days later.
Ingestion of embryonated eggs through contaminated water, food and bedding.
Preferred – combination of perianal sticky tape test, motility slide of the caecal and duodenal contents, and wet preparation slide of the large and small intestinal content
Faecal float of the GIT content
Anal swab technique
PCR of faecal material
The life cycle of the parasite, timing of cage changes, and treatment of cages must be considered when interpreting results.
Mice: Syphacia obvelata and Aspiculuris tetraptera
Rats: Syphacia muris
These species specificities are predilections, not obligate associations. S. obvelata and A. tetraptera has been reported in rats. S. muris have been reported in mice.
S. obvelata and S.muris - direct life cycle, 12-15d from the time of ingestion of embryonated eggs to the migration of female worms to the perianal region where eggs are deposited
tetraptera - direct life cycle, 23-25d from the time of ingestion of embryonated eggs to the production of eggs by the female worms in the descending colon
Eggs are persistent environmental contaminants which are very resistant to destruction
Remain infective in the environment for weeks
Rigorous sanitation methods are often required to rid animals of eggs
Screening of any introduced mice
Filter top/IVC cages for use in quarantine situations
Regular parasite examinations with treatment of infested animals
Prevention and Control
Barrier maintenance (control of animal and personnel entry) aids in preventing reintroduction
Disinfectants will not destroy pinworm ova, so they must be either physically removed (washing) or inactivated through heat sterilization (cages)
Regular removal of faecal material should be sufficient to remove embryonated ova and prevent re-infestation
Feed containing fenbendazole at 150ppm for three 7-day periods over 5 weeks or Avermectins (mainly represented by ivermectin) at an oral dose of 2.0mg/kg daily - effective against S. obvelata and S.muris (Fenbendazole efficacious against Aspiculuris)
Rederivation via hysterectomy and Caesarian section or embryo transfer
Dean H. Percy & Stephen W. Barthold, Pathology of Laboratory Rodents and Rabbits (Third Edition), 2007
Infectious Diseases of Mice and Rats National Research Council, 1991
Implications of infectious agents on results of animal experiments. Laboratory Animals, 1999, 33 Suppl 1: S39-87
Prevalence of viral, bacterial and parasitological diseases in rats and mice used in research environments in Australasia over a 5-y period. Laboratory Animals, 2011, 40 (11): 341-348
Kathleen R. Pritchett & Nancy A. Johnston, A Review of Treatments for the Eradication of Pinworm Infections from Laboratory Rodent Colonies. American Association for Laboratory Animal Science, 2002, 41 (2)