The country of Yemen is experiencing a huge coastal outbreak of the evil screw worm
Screw worm females go after bare flesh, laying 250-300 eggs in a host. When you feel that itch, whatever you do, don’t scratch it. The reason why they’re called screw worms is that the maggots will only burrow deeper, causing tissue damage and even death.
Once hatched, the maggots feed off the live flesh and fall down to the ground, where they pupate. The pupae reach adulthood 7 days later. They can then mate and lay over 4,000 eggs. They can also fly 125 miles, bringing their offspring and the plague inland.
Female, dorsal view
The New World screwworm fly, Cochliomyia hominivorax, is an obligate ectoparasite and will infest almost all warm-blooded livestock, wildlife and humans; it is unable to breed in carrion. These bluish to bluish-green flies have three prominent longitudinal black stripes on the thorax.
Female, lateral view.
The face and the eyes are orange-brown. The palps are short and thread-like (filiform) and the antennae are feathered to their tips.
Posterior spiracles of screwworm larva.
In the screwworm third-instar larva the posterior spiracles are large, each with a prominent dark-pigmented peritreme which apparently does not completely surround the three straight slit-like apertures.
Yemen, which has experienced a huge coastal outbreak of the evil screw worm is desperate for international aid. A Ministerial delegation was at the IAEA in Vienna, Austria, to seek emergency assistance to fight the evil worm.
However in Yemen, humans being affected by the pests is not the biggest problem. The vast majority who turn into “living hosts” are usually very young, old or infirm. The main problem is livestock.
“There are about 20,000 cases of livestock affected. Most of these are sheep and goats,” says Mansoor AlQadasi, General Director of the Central Veterinarian Laboratory. With increasing food costs, and mouths to feed, this is a huge problem that threatens the traditional way of life.
Larvae dropping from the wound
The larvae are fully developed in 5 to 9 days, leave the host and pupariate in the surface layers of the soil. Wounds infested by screwworm larvae become extensive and attractive to gravid females; consequently, the syndrome is self-perpetuating in endemic areas and the usual result is death of the struck animal.
It is hoped that like the outbreak in Libya in 1988, the international community will give aid and help eradicate the insects. One possible approach that worked successfully in Libya and South America is effectively to turn the insects against themselves: birth control on a massive scale. The approach entails using radiation to breed hundreds of thousands of sterile male screw worms, and reintroducing them into the wild.
If aid can be generated we might be able to screw over the screw worm, before they screw us.