3. What is Myiasis?
• The Infestation of animal tissue with Dipteran larvae.
• For example. Maggots Occurs predominantly in the tropics
and subtropics of Africa and the Americas.
4. Dermatobia hominis:
The Human Bot Fly
Classification
• Kingdom-Animalia
• Phylum- Arthropoda
• Class- Insecta
• Order- Diptera
• Family- Oestridae
• Genus- Dermatobia
• Species- D. hominis
6. The Human Bot Fly Life-cycle
• The Human Bot Fly Life-cycle
• Females “glue” their eggs onto the body of an arthropod
(usually a fly or mosquito)
• Eggs drop off the mosquito (or fly) during a blood meal.
• Eggs hatch in response to heat and larvae burrow into the
epidermis.
• Larvae then undergo 3 distinct developmental stages (instars)
within the host.
7. Three Larval Instars of D.
hominis
• The first instar is subcylindrical with concentric rows of small
backward facing spines encasing the larval body.
• The second instar has a pyriform (tapered) shape with 6
posterior spiracles.
• The third instar is the form that emerges from the lesion and
is a fusiform shape (2cm).
8. cont…
• Third instar larvae emerges falls to the ground and pupates in
the soil.
• Pupae develops further into mature, adult Bot Fly.
9.
10. Vectors for D. hominis
• Mosquitoes and other flies that require a blood meal are all
possible vectors for The Human Bot Fly's eggs.
12. Prevention/Treatment
• The most conventional way of removing the larvae is with a
simple surgical procedure that includes local anesthesia. Using
a scalpel to cut a slit to enlarge the wound, the larvae can be
taken out.
• In order to coax the larva out, the spiracles need to be
covered.
• They can be covered with bacon, petroleum jelly, beeswax, or
any other thick substance that prevents the larvae from
breathing.
• The larvae will come up out of the lesion to breathe allowing it
to be removed with forceps.
13. Cont…
• In some cases the larva maybe popped out by applying
pressure around the wound.
• two wooden spatulas to apply pressure to pop the larva out.
• Use of lidocaine injections underneath the cyst. This creates
pressure that pushes the larva out.
• After any of these procedures, antibiotics are given to prevent
infection.
• The wound should heal in one to two weeks with little or no
scarring.
