Pinworm in Laboratory Rodents

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Etiology

  • Syphacia obvelata (mouse) and S. muris (rat)
    • Life Cycle-11-15 days

      -Direct—Adults inhabit the colon and cecum. Eggs are shed in the feces or deposited on the perianal region of the rodent. The eggs are very light and aerosolize easily, facilitation infection. Embryonated eggs are ingested, resulting in infection. Embryonated eggs can survive at room temperature for extended periods of time and after they dry.

  • Aspicularis tetraptera (mice)
    • Life Cycle-23-25 days

      -Direct-see above

Diagnosis

  • Tape tests
  • Fecal exams
  • Examination of cecal and colonic contents

Effects on Research

  • Decreased body weight
  • Other complications

    • Rectal prolapse

    • Intussusception
    • Fecal impaction
    • Liver granulomas
    • Increased cortisol release
    • Unexpected immune responses
    • Impaired intestinal electrolyte transport
    • Athymic nude mice more susceptible
  • Increased operating costs for treatment and environmental decontamination

Immediate Action upon Detection

  • Isolate

    • Limits spread of ova through colony

    • Extent and duration dependent on personnel and facilities
  • Detect

    • Identify all rooms with patent infections

    • Consider these rooms contaminated or "dirty"
  • Treat

    • Treat all cages in affected rooms

    • Use an effective anthelmintic protocol
    • Multiple treatments over several weeks are necessary
    • Educate all personnel

      • Pinworms very transmissible to other rodents by personnel

      • New biocontainment measures
      • No significant zoonotic potential

Eradication

  • Control

    • Reroute traffic patterns

      • Affected rooms should be cleaned last

      • Investigators and animal health personnel should treat affected rooms last
    • Increased biosecurity

      • Ideally require scrub change and shower of all individuals leaving an affected room

      • Personnel and equipment should leave affected rooms into dirty corridor
      • Scrubs, caps, gloves, booties and spray disinfectant should be used routinely
      • Use of disposable instruments and equipment when possible
    • Eliminate

      • Anthelmintic therapy-expensive and research consequences

      • Thorough scrubbing of cages and other potential fomites
      • Increased frequency of cage changes if feasible
      • Cull affected animals

Establishment of a Pinworm-Free Colony

  • Monitor

    • Sentinel Program

      • High risk population

      • Maximize exposure to colony environment
      • Routine tape tests
      • Examination of cecal and colonic contents upon euthanasia
  • Prevent

    • Animals

      • Obtain stocks from sources that are known to be free

    • Personnel

      • Working with infected animals should not enter rooms with disease free animals

    • Quarantine

      • New animals from suspect sources

      • Monitor sentinels or cohabitants from same shipment

Updated June 18, 2007 by SAK