Habronemiasis
Keywords: Habronema, penis, stallion
Image size: 1650 x 1746px
Habronemiasis on the penis of a Quarter Horse stallion. This is due to infestation by the fly-borne larvae of Habronema muscae, H. microstoma and Draschia megastoma. The lesions these larvae cause are intensely pruritic and may occasionally cause hemosemen. Habronemiasis should be differentiated from squamous cell carcinoma by biopsy. A diagnosis is based on the presence of larvae in scrapings of the lesion. Oral ivermectin Rx is an effective treatment for habronemiasis when two treatments are given one month apart.
Note: Habronema spp. lay their eggs in manure piles and their larvae are ingested by the larvae of the housefly (Musca domestica) or Stable fly (Stomoxys calcitrans) which also develop in manure. The habronema larvae then emerge from adult houseflies or stable flies as they alight on horses. Fly control is therefore of great importance in the control of habronemiasis.
