Dermatobia hominis: Berne, nuche, ura, human botfly, tropical warble fly.

General Description: Adult females are about 12mm long and have no mouth parts for feeding. The thorax is dark blue and the short, broad abdomen is brilliant blue.

Life Cycle: Adult flies attach mosquitoes and deposit eggs on these transport hosts. A period of 6 days on the transport host is required for larval development within the eggs. Hatching can then occur when the mosquitoes land on animals to feed. The larvae penetrate the skin of the host animal through the mosquito bite. Larvae grow under the animal's skin and produce a painful swelling with a hole through which the larvae breathes. Mature larvae are about 25mm long after completing their development, some 5 to 10 weeks after entry. They leave the host and pupate in the ground for 5 to 10 weeks before emerging as adults. Blood sucking flies or ticks may also serve as transport hosts. Life cycle takes about 4 months.

Location: Cysts containing larvae or "warbles" under the skin are found on any part of the body, but more commonly on the front half.

Geographical Distribution: Mexico, Central and South America except Chile, and the island of Trinidad. It is thought that this parasite may now be in the United States.

Significance: Cysts are painful to animals and cause condemnation of skin at slaughter.

Effect on Host: Dermatobia larvae cause large painful swellings in subcutaneous tissue of the host. There are breathing holes through the skin, and these expose the underlying tissue to the air and possible invasion by other parasites and disease-producing organisms.

Diagnostic Information: Painful swellings in the subcutaneous tissue, each underlying a skin hole, suggest bot infestation. Diagnosis can be made by removal and examination of the larvae.

Diagnostic Information: Painful swellings in the subcutaneous tissue, each underlying a skin hole, suggest bot infestation. Diagnosis can be made by removal and examination of the larvae.

Control: Dips, washes or pour-on chemical agents. Ivermectin is effective in the control of Dermatobia hominis.

Cow severely infected on shoulders with Dermatobia		Close up of lesions – Dermatobia
Mature larvae – Dermatobia		Adult fly with egg packet