The Hindu : Kerala News : Mass participation necessary to eradicate filariasis

Online edition of India's National Newspaper
Saturday, Jun 05, 2004

Kerala

Kerala

Mass participation necessary to eradicate filariasis

Filariasis is the most common cause of lymphoedema and hydrocoele in India. This disease is seen in economically backward countries, infecting over 120 million people in 80 countries. India has 40 per cent of filariasis-infected people in the world and the annual loss in wages resulting from this disease is estimated to be U.S. $ 811 million very year.

Lymphatic filariasis is a parasitic disease caused by thin, thread-like filarial worms that are transmitted by mosquitoes. The adult worms lie deep in the lymph vessels in the scrotum, groin, axilla and around the breast where they may live for four to six years. These worms grow and mature in the lymph vessels and produce millions of microfilaria. Examining the blood at night can identify these worms.

When a mosquito bites a person who has microfilaria in his blood, it takes in microfilaria along with the blood. In the mosquito, microfilaria develops into infective larvae within one to three weeks. When this mosquito bites another person, he gets infected.

Filariasis infection is usually first acquired in childhood.

Recent studies have shown that filarial infection usually starts in children and young adults. Since the disease develops slowly over the years, the outward symptoms of filariasis are often seen mostly in adult life. Evidence of filarial infection has been found in the blood of even two-year old children. As they grow up, the incidence of infection increases further, almost reaching the adult infection rates by the time they are 15-16 years old. The adult filarial worms damage the lymph vessels even during early infection and this damage is very often permanent, resulting in this ugly disease later in life. So it is very important that this disease is prevented, especially in children.

Sufferings caused by the disease

Many recent studies have illustrated the devastating social, psychological, sexual and economic issues caused by the deformities that occur as a result of this disease. The massive swellings of the limbs in elephantiasis interfere with the day-to-day activities of these patients. Genito-urinary disease, especially hydrocoele, results in strong feelings of shame, fear and embarrassment and it is associated with sexual disability and dysfunction. Inability to care for oneself, isolation from the community, loss of social support and family stress are the other problems faced by these patients.

Elimination of filariasis

Based on the World Health Assembly resolution in 1997, the aim is to eradicate filariasis. The Global Programme for Elimination of Lymphatic Filariasis was launched in 2000. India, a signatory to the World Health Assembly resolution, plans to eradicate filariasis by 2015.

In India, 17 States and six Union Territories are endemic for filariasis. There are 31.26 million with microfilaria in their blood, 7.44 million with swelling of the limbs and 12.88 million with hydrocoele. It is estimated that 40.65 million episodes of acute attacks occur annually in the affected population.

Steps to check filariasis

Earlier, efforts were made to check the spread of filariasis by checking or preventing breeding of mosquitoes and selectively treating people who were carriers of microfilaria. However, this was found to be inadequate and was not cost effective.

Recent advances in the understanding of this disease have contributed to new hope that this disease could be eradicated globally. This programme for eradication of filariasis is based on a dual approach consisting of: interruption of transmission to prevent the disease in future generations and alleviation of the disability in those who already have the disease.

Mass drug administration

At present, the two strategies adopted by the Government of India are mass administration of five annual single doses of tablets of Diethyl Carbamazine Citrate (DEC), 6 mg per kg body weight and DEC (6 mg per kg) along with Albendazole (400 mg).

Administration of Albendazole brings down microfilaria levels more rapidly and this drug has a pronounced effect against intestinal worms. Albendazole is a costly drug that is now being supplied free for the eradication of filariasis all over the world by the major drug manufacturing company, Glaxo Smith Kline.

Both DEC and Albendazole are very safe drugs that have been used in clinical practice for several years. DEC is available as 100 mg tablets. The number of tablets to be taken is given below

Two to four years - one tablet

Five to 14 years - two tablets

15 and above - three tablets

Dose of Albendazole - one tablet of 400 mg

Principle behind MDA

Recent studies have shown that annual administration of a single dose of anti-filarial drugs maintains the microfilaria levels in the blood at very low levels, even at the end of the year. It is shown that the drug has to be given once every year for four to six years, which is the duration of the reproductive phase in the life cycle of the filarial worms.

The spread of the disease depends on the load of microfilaria in the blood of individuals in a community and the presence of appropriate mosquito species. Bringing down the levels of microfilaria in blood will prevent the spread of this disease since mosquitoes will then fail to pick them up and transmit the disease. To effectively prevent the transmission of filariasis by mosquitoes, the drugs would have to be consumed every year by at least 80 per cent of the population in the endemic States. Pregnant women, children less than two years of age and people with serious illness including heart and kidney disease are excluded from the programme.

MDA is now being carried out in India in 29 districts in nine States covering a population of 57.60 million. It is seen that the actual number of people who consume the drug is far less than the 80 per cent coverage required to prevent transmission of filariasis. Studies have shown that if higher coverage were not achieved, the administration of drugs would have to be continued for some more years. Many factors have been identified that contributed to the low drug coverage observed during the last few years of mass drug administration.

The main reason for non-compliance was the lack of adequate information regarding the filariasis eradication programme. For the success of the programme all people in the district, who appear otherwise healthy are also required to consume the drug, because at present, there is no way to identify and treat every infected individual.

Fear of reactions to the drug was another reason. Adverse effects are seen only in people who are carriers of microfilaria and this is on account of the worms being rapidly cleared from the body. So this is a welcome sign. There may be fever, headache, body ache or sore throat that may last for one or two days. These symptoms are usually mild, self-limiting and at the most relieved by paracetamol tablet.

Proper information regarding the importance of the filariasis elimination programme will go a long way in convincing people to consume the prescribed drugs.

The Global Programme for Elimination of Filariasis is presently being carried out in 37 endemic countries in the world using DEC and Albendazole.

By Dr. R.K. Shenoy

Chief, Filariasis Research Unit,

T.D.Medical College Hospital,

Alappuzha

Chief, Filariasis Research Unit,

T.D.Medical College Hospital,

Alappuzha

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