Q: What is Lymphatic Filariasis?
A: Lymphatic Filariasis (LF), commonly known as elephantiasis, is a vector-borne disease where filarial parasites are transmitted through mosquitoes to humans. The parasite causes damage to the lymphatic system and ends up with profoundly disfiguring lifelong permanent disabilities in humans. Lymphatic Filariasis (LF) is the 4th leading cause of permanent disability worldwide (World Health Organization 1998). Clinical symptoms include swollen limbs, breasts (lymphoedema) and genitals (hydrocele), or swollen limbs with dramatically thickened, hard and rough skin (elephantiasis). Filariasis is prevalent mostly in tropical regions and it is a parasitic disease caused by thread-like worms, or “microfilariae”. Each adult worm lives for about 4-6 years in the human lymphatic system, and female worms release millions of microfilariae (immature worms) that circulate in the blood and are then picked up by mosquitoes while feeding, and later transmit the disease to another human.
Q: What are the parasites that cause Filariasis?
A: Though there are three types of parasites causing lymphatic filariasis, in Sri Lanka so
far only two species: Wuchereria bancrofti and Brugia malayi are reported. The most
common parasite in Sri Lanka is Wuchereria bancrofti.
Q: How the disease is transmitted ?
A: It is transmitted through mosquitoes. The two types of mosquitoes transmitting lymphatic filariasis in Sri Lanka are Culex quinquefasciatus which transmits Wuchereria bancrofti (urban filariasis) and Mansonia species of mosquitoes which transmits Brugia malayi (rural filariasis).
Q: What are the biting hours of the above mosquitoes ?
A: Culex quinquefasciatus is a night biter (Between 10.00 p.m. to 2.00 a.m.) though Mansonia mosquitoes bite humans even during day time.
Q: What are the breeding sites of the vectors (mosquitoes) ?
A: Female Culex quinquefasciatus mosquitoes breed in stagnant unclean water.
Eg: blocked drains, broken latrine pits, and other polluted water collections
Female Mansonia mosquitoes breed in water bodies where aquatic plants (Salvinia
and Pistia plants) grow.
Q: How to get protected from mosquito bites?
A: Use mosquito repellents (smoke, vapor or creams), mosquito nets and wear long light coloured clothes in the night.
Q: What are the symptoms of Filariasis ?
A: Not everyone who is infected will develop symptoms. They might present with non- specific symptoms like nighttime fever, night cough, lymph node enlargement or itchy reddish patches.
Lymphoedema (swelling) of dependent body parts (legs, hands, genitalia, breast) occurs in the latter part of the disease due to the damage caused to the lymphatic system, by the parasite and its’ secretions.
Q: How to diagnose Filariasis ?
A: Filariasis is diagnosed mainly by Night Blood Film (NBF) in Sri Lanka. Filaria Antigen Test (FAT) and Filaria Antibody Test (Ig M and Ig G) can also be done to arrive at a diagnosis.
Q: What are the treatments available for Filariasis?
A: Patients who are found to be positive are treated with DEC (Diethylcarbamazine) and Albendazole. DEC will be prescribed for a duration of 12 days and the dosage will be calculated according to the body weight of the individual. Albendazole is given as a stat dose.
Patients with lymphoedema (upper limb, lower limb, breast and hydrocele) are referred to the lymphoedema clinics conducted by the AFC and the Regional Anti Filariasis Units located in eight endemic districts (Puttalam, Kurunegala, Gampaha, Colombo, Kalutara, Galle, Matara and Hambantota).
People with lymphedema can benefit from lymphedema management, and in the case of hydrocele surgical repair is offered.
Even after the adult worms die, lymphoedema can be developed.Prevent the lymphoedema from getting worse by following several basic principles:
- Carefully wash and dry the swollen area with soap and water every day. Dab and dry
the grooves and in-between toes. - the swollen arm or leg during the day and at night to move the fluid.
Perform exercises to move the fluid and improve lymph flow.
Disinfect any wounds. Use antibacterial or antifungal cream if necessary. Wear shoes adapted to the size of the foot to protect the feet from injury.
Q: What is Mass Drug Administration (MDA) ?
A: Both DEC and Albendazole are given as a single dose to the community on a large scale, to reduce the microfilaria densities and to reduce the transmission.
Q: When do the community receive MDA ?
A: Anti Filariasis Campaign is the technical body which decides when, where, and how to give MDA. Currently, MDA is given to the community within 500-meter radius from the residence of a positive patient.
Q: WHO ARE ELIGIBLE FOR MDA?
A: All people above 2 years will be eligible. Patients who are undergoing treatment for Diabetes, Hypertension (high blood pressure), and Dyslipidemia (high cholesterol) are also eligible for MDA.
MDA will not be given to children under 2years of age, breast feeding mothers (with children under 2 years), pregnant mothers and critically ill patients.
Q: Who are eligible for MDA ?
A: All people above 2 years will be eligible. Patients who are undergoing treatment for Diabetes, Hypertension (high blood pressure), and Dyslipidemia (high cholesterol) are also eligible for MDA.
MDA will not be given to children <2years of age, breast feeding mothers (with children
<2 years), pregnant mothers and critically ill patients.
Q: Benefits of treatment/MDA ?
A: The medicines will effectively reduce the density of microfilariae in the bloodstream and prevent the transmission of parasites from humans to mosquitoes.
Q: Side effects of the drugs ?
A: Fewer side effects are seen. If taken after meals side effects are lessened. Mild headache, nausea, dizziness and appearance of hives have been rarely reported. Along with its needed effects, the medicine may cause some unwanted effects. Check with your doctor immediately if any of the following side effects occur:
More common
(a) Itching and swelling of the face, especially the eyes Less common
(a) Fever
(b) Painful and tender glands in the neck, armpits, or groin
(c) Skin rash
Check with your doctor as soon as possible if any of the following side effects occur
(a) Loss of vision
(b) Night blindness
(c) Tunnel vision
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
(a) Headache
(b) Joint pain
(c) Unusual tiredness or weakness Less common
(a) Dizziness
(a) Nausea or vomiting
Q: Is Filaria eliminated from Sri Lanka ?
A: Sri Lanka was validated as a country which has eliminated lymphatic filariasis as a public health problem in 2016. A very low-grade transmission is continuing along the coastal belt in the endemic districts.
