Filariasis Guide

A parasitic disease that is the medical profession deems an infectious tropical disease is known as Filariasis. This disease is caused by round worms (filarial nematodes) in the super family filariae also know as Filarioidea.

In Humans

Humans are used as a host by eight known filarial nematodes. These filarial nematodes are divided into three groups in accordance to the positions within the body that they are in and they are: The serous cavity filariasis, the subcutaneous filariasis, and the lymphatic filariasis. The worms Mansonella perstans and Mansonella ozzardi, which occupy the abdomens serous cavity, cause the serous cavity filariasis. Transmitting vectors are either copodcrustaceans or blood sucking insects (mosquitoes or flies) in all cases. The guinea worm, Ochocerca vovulus, Mansonella and the African eye worm cause subcutaneous filariasis. The skins? subcutaneous fat layer is occupied by the worms. The worms Brugia timori, Brugia malayi, Wuchereria cause lymphatic filariasis. The lymphatic system is occupied by these worms and when the situation is chronic, these worms can be responsible for causing the elephantiasis disease.

When an individual is infected by filarial worms the condition can be classified as either amicrofilaraemic or microfilaraemic which depends mainly on if microfilaria is found in the peripehral blood.

The Lifecycle of the Worm

These worms have a complex life cycle that typically occurs in five stages. Following the mating of the male and female worms, the female gives birth by the thousands to live microfilariae. The microfilariae are then taken up by the intermediate host (vector insect) during the blood meal. The microfilariae molt, in the intermediate host, develops into infective (3rd stage) larvae. When an additional blood meal is taken, the intermediate insect injects larvae into the skins? dermis layer. Following one year, the larvae then molt through two additional stages and mature to become adult worms.

Diagnosis

The diagnosis of filariasis is typically through microfilariae identification on thin and thick blood film smears stained on a Giemsa, using the finger prick test. Through the finger prick test the blood is drawn from fingers tips? capillaries and blood extraction can be taken through larger vein but there is a strict window of the time of day that must be observed. The times that the blood is to be taken reflect the vector insects feeding activities. There are some filarial worms that produce microfilariae, such as in the case of the O. volulus and the M. streptocerca, and they don?t use the blood but reside only in the skin. Diagnoses, for these types of worms require the snipping of skin and can be performed any time.

Treatment

Treatment of lymphatic filariasis includes taking diethylecarbamacine three times day for three weeks and also five days each six month period with 100mgm doses. Fever is common in the early stages and if an acute attack Nsaids and antibiotics work well. Iakhs in young people and Benzathine penicillin 12 for adults can be taken to prevent further fever attacks. In the instance the swelling of the arms and legs a pitting and soft in the beginning stages, a person should wear fitting elastic socks or tightly tie the affected area with an elastic crepe bandage from the entire leg down to the foot during the day period but not necessarily at nighttime. Just socks or single elastic crepe may not be enough to reduce swelling around the ankle. A second bandage tied from the ankle to the foot can also be worn. It is useful to still the socks or bandage with benzathine penicillin in stage 3 or 4 if the swelling is still non pitting. The legs should also be washed with water and soup every day. Whitefield ointment can be helpful in the occurrence of verrucas nodules.