Prevention of Parasitic Worms and How They Infest

This parasitic worms include schistosomes and Filariasis which are onchocerciasis, loa-loa and elephantiasis that are caused by simulium fly, mangrove fly and Mosquitoes. We shall treat those worms one by one and their prevention.

Schistosomes

These are worms which lay their eggs in the veins of the bladder or the bowel. The eggs have spines which pierce the bladder or bowel and cause bleeding. Blood passes out with urine or faeces. If the urine or faeces is passed into, or washed into, water the larvae swim about until they find a certain water snail, enter its body, and multiply. These cercariae then leave the snail and enter the body again through the skin of a person bathing or walking in the water. They find their way to the veins, and cause the diseases called schistosomiasis or bilharzia.

Prevention of Schistosomes

1. Always use latrines and don't excrete in the water.
2. You should not bathe, walk, or wade in water which is known to be infected, and an alternative safe supply must be provided.
3. Treat cases.
4. Control or kill the snails.

Filariasis

Filarial worms are carried by:
The Simulium fly causing onchocerciasis.
The mangrove fly causing loa-loa.
Mosquitoes causing elephantiasis.

Onchocerciasis

the filarial worn onchocerca volvulus is carried by the simulium fly from one infected person to another. These flies are breed in fast-flowing streams, and bite people living near the water. The worm causes nodules under the skin, but when it reaches the eye it causes blindness, hence its other name of river blindness

Prevention of Onchocerciasis

The infected stream water is treated periodically by adding a solution of DDT.

Loa-Loa

A filarial worm called Loa-loa is carried by the mangrove fly. It moves about under the skin usually causing no symptoms, but causing itching and swelling (Calabar swellings) in different parts of the body. When this worm gets into the eye, it causes severe swelling though not much permanent.

Prevention of Loa-loa

This lies in preventing mangrove flies from breeding.

Elephantiasis

When the mosquito carrying the larvae bits a man, there larvae enter the body and pass to the lymphathics where they grow and breed. The diseases is caused by these filarial worms blocking the lymphatic vessels and stopping the circulation of lymph, thus producing great enlargement of the part from which the lymph cannot flow. This diseases, filariasis, can also cause hydroceles or swelling of the scrotum.

Prevention of Elephantiasis

1. Destroy all breeding-places of mosquitoes, especially 'Culex fatigans'.
2. Protect the house with screens and close all the doors at dusk.
3. Use mosquito-nets on all beds and cots.
4. Spray the house before dusk and keep it clean and light.
5. Obtain treatment early in the course of the disease.