Hi, I'm Jess Keating, and you're watching Animalogic: Second Nature. Warning, this episode
is very graphic. If you don't want to see
a maggot in a human ear, turn back now.
In the past, we've talked about insects that lay their eggs
in other insects. Jewel wasps that
zombify cockroaches, green-eyes wasps that
turn lady bugs into cocoons, and barnacles that turn crabs
into castrated egg incubators. But some insects
have bigger ambitions and lay their eggs in
much larger prey, like humans. This is myiasis.
[male announcer] The maggots immediately commence
feeding off of decaying food matter
in which they find themselves. These germ-laden flies may
bring her the unwanted gift of a bad tummy ache.
[Child crying] Myiasis, or flystrike, is part
of the developmental cycle of many species of flies.
It's just a way, a really gut-wrenching way,
for fly moms to ensure their babies have enough food.
[male announcer] House flies lay their eggs anywhere they find
the kind of media or food on which the fly larvae can feed
when they hatch. The pearly white eggs
can rest on a pencil point. This episode is going to be
absolutely horrific, so to balance it out,
here's a baby otter. [♪♪♪]
[♪♪♪] [♪♪♪]
[Jess] The larvae, or maggots,
need a handy source of food to grow
until they're ready to pupate. Many species lay their eggs on
decaying or rotting matter which is why maggots
are useful in forensics. But some species
prefer fresher meals and have adapted to
have their babies feed on the tissue
of living animals. There are several ways
fly larvae can be deposited, and they're all
absolutely horrifying. The most common way is to
lay eggs directly on skin. The mom looks for a soft,
warm place, such as a cow leg
or a human neck, to lay an egg.
[male announcer] The female fly has a
long tube, or ovipositor,
through which the eggs are laid.
A single house fly lays an average of 100-150 eggs at a time.
About eight hours later the eggs hatches.Some maggots have sharp,
curved mouth parts to help them cut through flesh,
access food, and find the most desirable resting spots.
Their mouth parts also make them look like mini walruses.
I never thought I'd say this, but that maggot is adorable.
After finding a suitable area in the subcutaneous tissue,
it begins to feed and stays there
until it's ready to pupate. Inflammation and bacterial
infections follow soon after.
These infections can get pretty bad really quickly,
as the scent of the maggots of some species,
like blowflies, attracts more flies to lay their eggs.
A bad blowfly infestation can kill its host
in a matter of days. While in the host flesh,
some species of larvae use enzymes in their poo
and grinders in their mouth to break down proteins.
This helps them grow very fast. In the right conditions,
some species can go from egg to pupa in less than a week,
though some take longer to develop.
Botflies, for example, can stay under the skin for up to a year.
Okay, that's enough botflies. Here's a baby tapir.
Aww, look how cute he is. [♪♪♪]
[male announcer] Meanwhile, man's ancient enemy
continues to multiply, multiply, multiply.
In hum ans, myiasis is most
commonly caused by the tumbu fly in Africa and the human botfly
in Central and South America. The human botfly,
dermatobia hominis, is a parasite of many mammals,
including monkeys, and of course, humans.
Instead of risking getting close to their host,
it uses secondary vectors such as mosquitos and ticks.
The botfly grabs these insects and lays their eggs on them.
When they bite a host, the eggs fall off, hatch,
and the larvae enter the body. Botflies can live in muscle
and skin tissue, but they're also known to live
in the host pharynx, gut system, and internal organs.
Luckily, they can't live in infected tissue,
so they're flystrike, though large and long lasting,
are generally less lethal than in other species.
If you get a human botfly flystrike,
do not try to remove it with a pair of tweezers.
This can break the larvae and leave dead pieces of larvae
under the skin which can cause septic shock.
Anti parasitic medications are usually the safest bet,
especially when the larvae is in a sensitive area
such as the eyelid. Then it jumps out of the wound
and buries itself in the ground until its metamorphosis
is complete. Having maggots under your
skin is pretty freakin' gross, but when they live in areas
other than the skin, they can cause
permanent tissue damage. [male announcer] Now, if you
will lend me your ears while watching this picture
on the screen, I will tell you about these
invisible ways-- [Jess] In oral myiasis,
the maggots feed on the soft tissue of the middle
ear. In some cases, they can go to the brain and damage it
due to the inflammation it creates
and the bacterial infections it causes.
The first symptoms are generally crawling sensations and buzzing noises,
so that's something to keep your eye on
for the rest of your life. Myiasis in the eyelid
is relatively common, but the damage is much worse
in the rare cases when the maggot enters the eye.
It can cause hemorrhage and detachment of the retina
and invasion of the optic nerve which can cause permanent
blindness in the affected eye. Time for another cute break. Here's
a baby quokka. [♪♪♪]
[male announcer] Now a new generation of flies
is ready to carry on the spread of filth and disease.
When myiasis happens to people, it's generally treated
very quickly. But when it happens to
our pets and livestock, it's much harder to diagnose
and treat. The sheep botfly alone causes
every year. This has created economic
incentives to fight these flies with everything we got.
There have been several attempts to combat
the different fly species that cause myiasis.
On e of the most successful
ones took place in the U.S. and Mexico, where millions of large,
sterile primary screw flies were released to mate
with fertile flies. [male announcer]
Within the last decade, been used to sterilize
millions of pupae of the male screwworm fly
whose parasitic larvae, breeding in the flesh
of cattle, deer, and other animals,
posed a major problem to our livestock industry
in the southern half of the nation.
[Jess] After several generations,
the sterile screw flies out competed the wild ones
and the species was completely eradicated in North America
in 1991. Early successes
have fueled research to prevent and combat future outbreaks.
One of the projects consists of making synthetic odor baits
to attract the flies and get them to lay their eggs there
instead of on animals. But not everything about maggots
is the worst thing you've ever heard.
We've actually been using them since ancient times.
Flystrike has been amazingly useful in medicine.
Some maggots specialize in dead tissue,
so they can be used to clean necrotic tissue in live animals
and humans. The treatment consists of
inserting five to ten chemically disinfected
maggots per square centimetre of wound for four days.
During this period, maggots secrete a fluid that breaks down
dead tissue and bacteria into a soup that they can ingest.
In the U.S. alone, Well, this has been enough
maggot talk to last for a few years.
I'm gonna go home now and watch videos of baby seals.
Actually, let's watch baby seal videos together.
They do not have myiasis. [♪♪♪]
[♪♪♪] [♪♪♪]
So what should we talk about next?
Don't say maggots. As always, let us know
in the comments down below and please subscribe
for new episodes every week.
Thanks for watching. [♪♪♪]
I challenge anybody to say that. [Andres] A bad blowfly
inf-u-station-- Yeah, yeah, you see?
You wrote it and you can't even say it.
Can you say that, Dylan? [Dylan] A bad blowfly
inf-lu-station-- Yeah, "inf-lu-station."
Yeah, you see? That's the problem.
These jerks want me to say, A bad blowfly infestation. A
bad blowfly infestation. You're gonna see me.
I'm gonna get it out and I'm gonna forget the next part.