Diseases / List of Parasitic Diseases / Disease description:

Pinworm Infection in Lagomorphs

Passalurus ambiguus egg. Click here for full page view with caption.

INFORMATION AVAILABLE

GENERAL INFORMATION

CLINICAL CHARACTERISTICS & PATHOLOGY

INVESTIGATION & DIAGNOSIS

TREATMENT & CONTROL

SUSCEPTIBILITY & TRANSMISSION

ENVIRONMENT & GEOGRAPHY

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General and References

Disease Summary
Pinworms are found in the large intestines of various mammals. In some species infection causes intense perianal pruritis associated with adult females laying thei eggs in the anal/perianal region. (B24) 
Lagomorphs
  • Pinworms are reported to occur in a variety of lagomorphs worldwide. (B614.11.w11)
  • They are generally thought to be non pathogenic as they rarely cause clinical signs and they may be found incidentally at post mortem. Heavy infection may lead to perineal dermatitis and ill thrift. (B600.16.w16, B602.19.w19, B603.3.w3, B609.2.w2, B614.11.w11)
  • Pinworms may benefit digestion. (B603.3.w3)

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Alternative Names (Synonyms)
  • Oxyurid infection.

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Disease Type
Parasitic Infection

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Infectious/Non-Infectious Agent associated with the Disease
Pinworms are members of the family Oxyuridae and are small to medium sized worms with three conspicuous lips. Female pinworms are usually significantly larger than the males and have long, tapering tails; the vulva is near the anterior end of the body. The eggs usually have one side that is flattened. The life cycle is direct (no intermediate host needed). (B24, B614.11.w11)
  • Passalurus ambiguus - the common rabbit pinworm. 
    • Oxyuris ambigua is a synonym of Passalurus ambiguus. (B614.11.w11)
    • These small worms may be found in the small intestine, caecum and colon of rabbits. (B600.16.w16, B602.19.w19, B609.2.w2, B614.11.w11)
    • Large numbers may occur in the colon and the caecal ampulla but it is rare for them to be associated with a blockage. (B603.3.w3)
    • Life cycle: adult worms are predominately found in the anterior portion of the caecum and large intestine. Juvenile stages of this parasite inhabit the small intestinal and caecal mucosa. Infection occurs via ingestion of infective eggs. (B24, B614.11.w11)
    • Eggs: 95 - 103 x 43 µm, flattened on one side. Adult females 9 - 11 mm long, tail tapering, 3.4 - 4.5 mm, About 40 circular striations mark the distal cuticle of the extremity. Adult males 4.3 - 5 mm long. Oesophagus has a prebulbar swelling and a strong bulb. In the male there is a whip-like appendage and small caudal alae which are supported by papillae. (B24)
  • Passalurus nonanulatus 
    • This species can also be found in rabbits but not as commonly as the morphologically similar Passalurus ambiguus. (B603.3.w3, B614.11.w11)
    • This species has been reported in wild lagomorphs in the USA; some animals were found to be infected with over 1,000 parasites. (B614.11.w11)
  • Dermatoxys veligera
    • Adult worms are found free in the caecal lumen; the fourth stage larvae attach themselves to the caecal mucosa by hooks. (B614.11.w11)
    • Found in the caecum and colon of Sylvilagus spp. and Lepus spp. in North America and Brazil. (B24)
    • Male 8 - 11 mm long, female 16 - 17 mm.
    • Three lips, a short mouth-vestibule which contains three teeth.
    • Females have a long, tapering tale.
    • Males have caudal alae. Single spicule.
    • Cervical alea are present.
    • Ovaries "marked and deeply coloured."
    • Eggs: thick-walled, 110 x 50 µm, operculate, asymmetrical.

    (B24)

  • Dermatoxys (Heteroxinema) vlakhaasi in hares in South Africa. (J62.64.w3) 
  • Dermatoxys hispaniensis in Oryctolagus cuniculus - European rabbit in Navarra, Spain. (J175.73.w1)
  • Dermatoxys romerolagi described from wild Romerolagus diazi - Volcano rabbit. (J469.360.w1)

Infective "Taxa"

Non-infective agents

 --

Physical agents

 -- Indirect / Secondary

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References

Disease Author

 Nikki Fox BVSc MRCVS (V.w103)
Click image for main Reference Section

Referees

 William Lewis BVSc CertZooMed MRCVS (V.w129); Anna Meredith MA VetMB CertLAS DZooMed (Mammalian) MRCVS (V.w128); Richard Saunders BVSc BSc CertZooMed MRCVS (V.w121)

Major References / Reviews

Code and Title List

 B24, B600.16.w16, B601.13.w13, B602.19.w19, B603.3.w3, B609.2.w2, B610.23.w23, B614.11.w11
J83.15.w3, J29.5.w1

Other References

Code and Title List

 J1.16.w18, J1.19.w15, J1.24.w13,  J1.26.w14, J1.32.w11, J1.43.w3, J11.55.w2, J40.4.w2, J40.4.w3, J40.7.w1, J40.7.w2, J40.8.w1, J40.11.w1, J46.212.w1, J175.59.w1, J175.60.w1, J175.73.w1, J175.73.w2, J194.24.w1, J331.84.w1, J331.103.w1, J332.28.w3, J469.34.w1, J469.55.w1, J427.63.w1, J469.106.w1, J469.125.w1, J469.136.w1, J469.151.w1, J469.153.w1, J469.360.w1, J469.424.w1, J469.457.w1, J469.495.w1, J505.31.w1

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Clinical Characteristics and Pathology

Detailed Clinical and Pathological Characteristics
General Oxyuridae are small or medium-sized worms which live in the large intestines (caecum, colon, appendix) of various mammals. Gravid females of some species migrate to the anus or perianal skin to lay their eggs, causing intense pruritis in the host. (B24)

Clinical Characteristics

 Intense perianal pruritis in the host with some species. (B24)
Lagomorphs Pinworms are generally thought to be non-pathogenic as they rarely cause clinical signs. However, in heavy infestations the following clinical findings have been reported:
  • Perineal dermatitis with accompanying pruritus: moderate to severe perineal pruritus may lead to self trauma.
  • Ill thrift: weight loss (even emaciation) and poor haircoat.
  • Diarrhoea, also "constipation with meteorism." (J83.15.w3)
  • Apathy alternating with agitation. (J83.15.w3)
  • Poor reproductive performance: this may affect breeding colonies. 
  • Rectal prolapse (this is rare).
In young rabbits: a heavy infestation of this worm may be a contributing factor to the enteritis complex that can occur around weaning.

(B600.16.w16, B601.13.w13, B602.19.w19, B603.3.w3, B609.2.w2, B610.23.w23, J83.15.w3)

Mixed nematode infection:
  • Unsatisfactory breeding performance and poor condition were reported in a rabbit colony that was infected with both Passalarus ambiguus and Obeliscoides cuniculi. Improvement was seen following anthelmintic treatment. (B614.11.w11)

Incubation

 --
Lagomorphs --

Mortality / Morbidity

 --
Lagomorphs
  • This is considered the most common nematode of pet rabbits. (J34.24.w3, J29.5.w1)
  • Pinworms are generally thought to be non-pathogenic as they rarely cause clinical signs. (B600.16.w16, B602.19.w19, B603.3.w3, B609.2.w2, B614.11.w11)
  • Pinworm infection in laboratory rabbits has been reported as common. (B601.13.w13, B610.23.w23, B614.11.w11)
  • Some lagomorphs have been found to be infected with over 1,000 Passalarus nonanulatus pinworms. (B614.11.w11)

Pathology

 --
Lagomorphs
  • Adult pinworms are grossly visible in the lumen of the caecum or large intestine. Juvenile stages of pinworms may be seen in the mucosa of the small intestinal or caecum. (B614.11.w11)
  • No pathology has been ascribed to adult Dermatoxys veligera infection. However, small ulcers may be seen with the attachment of the fourth stage larvae to the caecal mucosa. (B614.11.w11)

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Human Health Considerations
Pinworms are host specific and therefore not transmissible to humans. (B602.19.w19, B609.2.w2)

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Susceptibility / Transmission

General information on Susceptibility / Transmission
--
Lagomorphs
Susceptibility
Transmission
  • Direct live cycle, infection by ingestion of infective eggs. (B24)
  • Faecal - oral route. 
    • Eggs are passed in faeces and then re-ingested by the same rabbit or ingested by other rabbits in the environment.

(B609.2.w2, B614.11.w11)

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Disease has been reported in either the wild or in captivity in:

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

(List does not contain all other species groups affected by this disease)

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Disease has been specifically reported in Free-ranging populations of:

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

(List does not contain all other species groups affected by this disease)

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Environment/Geography

General Information on Environmental Factors/Events and Seasonality

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Regions / Countries where the Infectious Agent or Disease has been recorded
  • Worldwide (B614.11.w11)

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Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

  • --

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General Investigation / Diagnosis

General Information on Investigation / Diagnosis
--
Lagomorphs
  • Presence of adult worms
    • Adult Passalarus ambiguus are 5 - 10 mm long and thread-like. (B600.16.w16)
    • Sexual dimorphism occurs:
      • Female worms: may be longer than male worms (6.6 mm) and have a longer tail. (B609.2.w2)
      • Male worms: 4.1 mm long, 300 µm in diameter and they have a single curved spicule. (B609.2.w2)
    • They may be seen around the anus/perineal area. (B609.2.w2, J29.5.w1)
    • They may be an incidental finding in the lumen of the colon or caecum during abdominal surgery or at post mortem examination. (B609.2.w2, B614.11.w11, J29.5.w1)
    • They may be seen in the faeces. (B602.19.w19, B609.2.w2, B614.11.w11, J29.5.w1) 
  • Faecal float or smear
    • Identification of eggs or adult worms. (B602.19.w19, B609.2.w2, B614.11.w11)
    • Eggs: Ovoid but flattened asymmetrically and capped at one end. (B603.3.w3)
    • Faecal egg counts can be used to monitor infection levels post-treatment. (B609.2.w2)
    • See Clinical Pathology of Lagomorphs - Faecal analysis
  • Anal adhesive tape test. (J83.15.w3)
Related Techniques
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Similar Diseases (Differential Diagnosis)
--
 

(B609.2.w2)

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Treatment and Control

Specific Medical Treatment
--
Lagomorphs
  • Treatment may not be necessary if the pinworms are just an incidental finding, e.g. at surgery; treat if symptomatic or if the owner reports worms around the rabbit's anus. (B609.2.w2)
  • Treat any secondary perineal pyoderma. (B609.2.w2)
  • Recurrence is common, even if a rabbit is housed on its own because of the act of caecotrophy and therefore the rabbit will continue to reinfect itself. (B609.2.w2)
Larvicide / Adulticide Anthelmintics
  • Fenbendazole (J29.5.w1)
    • 10-20 mg/kg orally and then repeat in 10-14 days. (B602.19.w19, B609.2.w2)
    • 25 ppm in feed for five days was effective at eliminating both immature and adult pinworms. (J83.15.w3)
      • If individuals are showing reduced appetite due to severe infection, 50 ppm in feed ensures an adequate dose for all rabbits. (J83.15.w3)
  • Thiabendazole
    • 50 mg/kg orally and then repeat in 10-14 days. (B602.19.w19, B609.2.w2)
  • Piperazine (B24, J29.5.w1)
    • Orally: 200 mg/kg and then repeat in 14 days. (B602.19.w19, B609.2.w2) OR
    • In feed: at 0.5 g/kg per day for two days, for adult rabbits; 0.75 g/kg per two days for juvenile rabbits. (B602.19.w19) OR
    • In drinking water: 100 mg/100 mL of water for one day and then repeat in ten days. (B602.19.w19, B614.11.w11)
  • It may be necessary to carry out repeat treatments. (B609.2.w2)
  • Treat all the rabbits in the environment. (B609.2.w2)
  • Note: Ivermectin is not effective against this nematode. (B600.16.w16, B603.3.w3, B609.2.w2, J1.32.w11, J29.5.w1)
  • Monitor faecal egg counts post-treatment. (B609.2.w2)
Related Techniques

 
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General Nursing and Surgical Techniques
--
Lagomorphs
  • Remove adult pinworms from perineal area. (B602.19.w19, B609.2.w2)
  • Wash the perineal area with detergent at the same time as an anthelmitic is given. (J29.5.w1)
Related Techniques
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Preventative Measures
Vaccination --
Lagomorphs --
Prophylactic Treatment

--
Lagomorphs --
Related Techniques
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Environmental and Population Control Measures
General Environment Changes, Cleaning and Disinfection --

Lagomorphs
  • Clean the environment with detergent at the same time that anthelmintic treatment is given. (J29.5.w1)
  • Note: "Environmental cleanup to kill pinworm eggs is difficult". (B602.19.w19)
Population Control Measures --
Lagomorphs --
Isolation, Quarantine and Screening --
Lagomorphs --
Related Techniques
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