.

Lymphatic filariasis Lymphatic filariasis (also known as

elephantiasis) is a parasitic disease caused by, three types of parasitic worms: Wuchereria bancrofti, Brugia malayi, and Brugia timori. . The adult worms only live in the human lymph system. And microfilaria circulate in peripheral blood and are available to

infect mosquito vectors

when they come to feed.

Epidemiological features Agent factors: Agent: Wuchereria bancrofti, Brugia malayi, and

Brugia timori. Reservoir of infection: In human the source of

infection is a person with circulating Mf in peripheral blood.

Host factors: Age: All ages are susceptible to infection. Sex: In most endemic areas Mf rate is higher in

men.

Cont.. Social factors: It is associated with

urbanization, industrialization, migration of people, illiteracy, poverty and poor sanitation.

Environmental factors: a) Temperature in between 22-38 deg. C is a

favorable condition for the survival of filaria. b) Drainage: It is associated with bad drainage.

c) Town planning: Inadequate sewage disposal and lack of town planning have increase the problem of filariasis.

Mode of transmission Filariasis is transmitted by the bite of infected vector

mosquitoes. The parasite is deposited near the site of puncture.

It passes through the punctured skin or may penetrate the skin on its own and finally reach the lymphatic system.

The dynamics of transmission depends upon the man-mosquito contact (e.g. infective biting rate).

Incubation Period: most commonly 8 to 16 months, but may be longer than this.

Signs and symptoms The clinical manifestations comprise filarial fever,

lymphangitis, lymphadenitis, lymphoedema of the various parts of the body and epididymoorchitis in male.

In chronic filariasis, the main clinical features are hydrocele, elephantiasis and chyluria.

Lymphatic filariasis is rarely fatal, but it can cause recurring infections, fevers, severe inflammation of the lymphatic system, and a lung condition called tropical pulmonary eosinophilia (TPE). In about 5% of infected persons, a condition called elephantiasis causes the legs to become grossly swollen.

Signs and symptoms The condition is associated with huge and disfiguring

enlargement of a limb, or areas of the trunk. In addition, the skin usually develops a thickened,

pebbly appearance and may become ulcerated and darkened.

Other symptoms can include fever, chills and a general feeling of ill health.

The disease may also affect the scrotum may become enlarged, and the penis may be retracted under the skin.

Elephantiasis The most spectacular symptom of lymphatic filariasis

is elephantiasis thickening of the skin and underlying tissues.

Elephantiasis affects mainly the lower extremities. This can lead to severe disfigurement, decreased

mobility, and long-term disability. Testicular hydrocele is a disfiguring enlargement of the scrotum.

People with the condition often have to contend with social as well as physical problems.

They are also frequently unable to work because of their disability.

Diagnosis Clinical features The diagnosis is made by identifying

microfliariae on a Giemsa stained thick blood film. Blood must be drawn at night, since the microfilaria circulate at night, when their vector, the mosquito, is most likely to bite.

Serological tests: To detect antibodies to Mf and adults using immunufluorescent and complement-fixing techniques cannot distinguish between past and present infection.

Treatment Drugs such as albendazole and

diethylcarbamazine (DEC) have been shown to be effective in killing the parasites.

Careful cleansing of wound can also have a significant impact, helping to heal infected areas.

Measures to improve the flow of the lymphatic fluid, such as raising and exercising the swollen body part can also help. In some cases, pressure bandages to reduce swelling.

Prevention and control Prevention centers on mass treatment with anti-

filariasis drugs to prevent ingestion of larvae by mosquitoes, public health action to control mosquitoes, and individual action to avoid mosquito bites. To avoid being bitten by mosquitoes:

If possible, stay inside between dusk and dark. This is when mosquitoes are most active in their search for food.

When outside, wear long pants and long-sleeved shirts.

Spray exposed skin with an insect repellent. vector control

Vector control Anti larval measures: a) By chemical control,

such as mosquito larvicidal oil, pyrosene oil. b) Breeding is controlled by removing pistia plant from water collections. c) Environmental measures, such as flling up of ditches and drainage of stagnant water, adequate maintenance of septic tanks.

Anti adult measures: indoor residual spraying Personal prophylaxis: Avoidance of mosquito

bite by use of mosquito nets. Screening of the houses.