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3.21 Cuterebriasis – Small Animals

Learning Objectives

  1. Know what causes cuterebriasis in dogs and cats and how they get the disease.
  2. Learn the clinical signs and the time of the year that lesions typically develop.
  3. Learn the body sites often affected.
  4. Know how to manage cuterebriasis.

  1. General Considerations

    1. Adult Cuterebra flies are large and bee-like and neither bite nor feed.
    2. They are not directly attracted to a host species but the females lay their eggs along rabbit runs and near rodent burrows.
    3. If a host brushes up against the eggs, they hatch instantaneously.
    4. The larva enters the body via natural body openings, skin penetration or ingestion during grooming the contaminated fur.
    5. The natural hosts are usually rabbits and other rodents.
    6. Rabbit Cuterebra larvae are less host-specific and usually affect cats and dogs.

  2. Cause

    1. Cuterebra larvae.

  3. Clinical Signs

    1. Lesions are usually noted in late summer or fall.
    2. The larva produce a nodule of 1 to 2 cm in diameter, which develops a pore.
Cuterebra larvae protruding through a pore on the center of a nodule formed on the abdomen of a dog with cuterebriasis.
Cuterebra larva protruding through a pore on the center of a nodule formed on the abdomen of a dog with cuterebriasis.
Cuterebra larva removed from a nodule localized on the abdomen of a cat.
Cuterebra larva removed from a nodule localized on the abdomen of a cat. Courtesy of Prof. Stephen White.
    1. Nodules are typically localized to the head, neck and trunk.
    2. Because dogs and cats are abnormal hosts, the larva may undergo aberrant migrations to the brain, pharynx, nostrils, and eyelids.

  2. Diagnosis

    1. Visualization of the larvae by enlarging the pore.
    2. Larva is 5 to 10 mm long, is dark-brown to black and has spines or spicules.

  3. Treatment

    1. The pore or fistula should be enlarged and the larva removed with a mosquito forceps.
    2. If larva is not removed intact, the retained parts may cause allergic or irritant reactions.
    3. Keep the wound clean and expect the second intention healing to be slow.

Important Facts

  • Dogs and cats contaminated with eggs of rabbit Cuterebra can develop subcutaneous nodules due to the migration of Cuterebra larva to the skin.
  • Nodules develop a breathing pore or fistula and are usually located on the head, neck, and trunk.
  • Lesions are usually noted in late summer and fall.
  • Aberrant migrations to the brain, pharynx, nostrils and eyelids can occur.
  • Treatment involves careful extraction of the larva in addition to keeping the wound clean until the slow second-intention healing takes place.

References

Pezzi M, Bonacci T, Leis M et al. Myiasis in domestic cats: a global review. Parasit Vectors 2019; 12:372.

Rutland BE, Byl KM, Hydeskov HB et al. Systemic manifestations of Cuterebra infection in dogs and cats: 42 cases (2000–2014). J Am Vet Med Assoc 2017; 251: 1432-1438.

Scott DW, Miller WH, Griffin CE:  Parasitic Skin Diseases.  Small Animal Dermatology. 5th edn. Philadelphia: W.B. Saunders Co., 1995; 461.

License

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Small and Large Animal Dermatology Handbook, Vol. 1 Copyright © 2025 by Sheila M.F. Torres, DVM, MS, PhD, DACVD is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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