INTRODUCTION

            The former Filariology division was expanded and renamed as Helminthology Division in 1980. This division undertakes Research, Training and Services on filariasis, guineaworm and intestinal parasitic diseases. The Division carries out experimental and community based research studies to elucidate information on epidemiological, entomological, serological and chemotherapeutic aspects of lymphatic filariasis for the effective control of the diseases. The research and training activities on filariasis are carried out jointly by the headquarters and three RFT&RCs at Calicut and Rajahmundry and Varanasi and B. malai Research Unit at Shertalai (Kerala), all situated in the filaria endemic areas. Research activities on filariasis in collaboration with ICMR and WHO are planned, coordinated and evaluated from time to time to evolve a suitable control strategy. The division has a Central Survey Team which monitors transmission of filariasis in the known non-endemic areas of the country and also undertakes surveys in the endemic areas on request from States/ Union Territories and other organisations.

The Division is the focal point for planning, guiding, Coordinating and evaluating the implementation of the Guinea Worm Eradication Programme (GWEP) in the seven endemic States viz., Rajasthan, Madhya Pradesh, Karnataka, Maharashtra, Gujarat, Andhra Pradesh and Tamil Nadu as well as non-endemic states throughout the country. Training courses on GWEP for health officials and public health engineers are also organized.

Research activities for development of simple control strategy on intestinal parasitic infections as well as training courses are also carried out by the division.

Training courses for filarial control are regularly arranged at the three branches to increase trained personnel in National Filaria Control Programme.

Preserved specimens of cyclops, guineaworm, ova and cyst of intestinal parasites and human filaria slides are supplied to various research and teaching institutions/organisations.

Branches

            There are three Regional Fialria Training & Research Centres (RFT & RC) functioning at Calicut in Kerala, Rajamundry in Andhra Pradesh and Varanasi in Uttar Pradesh. These centers were established during 1955, 1963 and 1965 respectively and conducting training course for health personnel for manning the National Filaria Control Programme in different regions of the country. A field station of the Centre, B. Malayi Research Unit is functioning at Shertalla, Alleppey district of Kerala. This unit has been converted into a research Unit since 1980 with headquarters at RFT & RC, Calicut and field station at Shertalla. These branches carry out following activities:

• Filaria Clinics

  Two day clinics, twice a week on Mondays and Thursdays and two night clinics twice a week on Mondays and Tuesdays are being conducted. Patients were examined and treatment/advice given during day clinics. Blood smears were collected from persons attending the night clinics and examined for evidence of microfilaraemia. At Calicut branch alone Up to the year 2000, 209487 patients were given treatment/advice.

• Research

  Research studies on Biochemical clinical, Epidemiological, Entomological, immunological, Socio-economic and Therapeutic aspects of Lymphatic Filariasis both Wuchereria bancrofti and Brugia malayi are undertaken in the Centre and its field station at Cherthala. Diagnostic and referral services on filariasis are provided to Public and Medical Institutions.

• Manpower development

  Teaching and training in filariasis and its control are imparted to Medical Officers/Biologists, Inspector/Technicians/ Supervisors and other field staff employed under National Filaria Control Programme in the country. Short duration lecture cum demonstration classes on filariology are also organised to students of Medical Colleges, School of Nursing and Trainees of Health and family Welfare Training Centre from time to time. From 2nd October, 2000, specialised training in morbidity management is also conducted.

The main activities of the division are described below.

GUINEA WORM ERADICATION PROGRAMME- INDIA.

Guinea worm (GW) disease is caused by the parasite Dracunculus medinensis and is transmitted through drinking water from unsafe sources like step well, ponds, etc. containing infected water fleas (Cyclops). The adult worm measuring 60 to 100 cm in length emerges through the skin, usually lower limbs, causing severe swelling, ulceration and discomfort to the patient. The disease causes incapacitation to the patient who is unable to perform his regular work, resulting in economic and production loss to the patient and family. The disease mostly occurs in rural areas with inadequate safe drinking water supply and peaks during the summer season when there is scarcity of water. The disease is transmitted when patient(s) enter into unsafe water sources, wherein the emerging guinea worm discharges its embryos into water which are taken up by the vector Cyclops. Subsequently, when a healthy person drinks this water containing infected Cyclops, the individual gets GW disease after a period of one year.

Encouraged with the success of "Small-pox Eradication", the Ministry of Health & F.W., Govt., of India launched the National Guinea Worm Eradication Programme (GWEP) in 1983-84 as a centrally sponsored scheme on 50:50 sharing basis between Centre and States with the objective of eradicating guinea worm disease from the country. The National Institute of Communicable Disease (NICD), Delhi functions as the nodal agency for planning, co-ordination, guidance and evaluation of GWEP in the country. The programme is implemented by the endemic State Health Directorates through the Primary Health Care System. The Ministry of Rural Development, Govt. of India and State Public Health Engineering Departments (Rural Water Supply) assist the Programme in provision and maintenance of safe drinking water supplies and conversion of unsafe drinking water sources, on priority in the guinea worm affected areas.

The GWEP envisaged the efficient implementation of well defined strategies, namely

• Guinea worm case detection and continuous surveillance through three active case search operations and regular monthly reporting

• GW case management

• Vector control by the application of Temephos in unsafe water sources eight times a year and use of find nylon mesh/double layered cloth strainers by the community to filter cyclops in all the affected villages

• Health education

• Trained manpower development and

• Provision and maintenance of safe drinking water supply on priority in GW endemic villages

• Concurrent evaluation and operational research

NICD with the financial support from WHO deployed epidemiological surveillance teams in endemic states which closely monitor the Programme and help the district/PHC authorities in effective implementation of various GWEP operational components especially surveillance and GW case containment measures.

GWEP - Achievement and Status

At the beginning of the Programme i.e. in 1984, there were around 40,000 GW cases in 12,840 villages in 89 districts of seven endemic States. During 1996 only 9 guinea worm cases have been recorded in three villages from Jodhpur (Rajasthan), rest of the country continued to remain free from guinea worm disease. Year wise and state wise cases and effected villages are mentioned in Annex 1. The States of Tamil nadu, Gujarat and Maharashtra and Andhra Pradesh were deleted from the list of GW endemic states on being free from GW disease for more than three continuous years. During 1998 and till October 1999, no guinea worm case has been reported from any part of the country.

During 1996 nine guinea worm cases have been recorded in three villages of Jodhpur District (Rajasthan), all of which were adequately contained. Last Case was reported in July 1996. Eradication of GW disease from India will be another major national achievement of recent time.

Progress of the guinea worm disease endemic areas and subsequent deletion is depicted in tables and graphics below.

Table

Trends of GW case incidence since 1984

Yearly decline in guinea worm cases and endemic villages in the country

All along the programme the progress was evaluated by independent experts. The last of these evaluations the Seventh Independent Evaluation of GWEP was conducted in April 1999. In this twenty teams were sent to seven erstwhile endemic states and fourteen non-endemic states/UTs. This Seventh evaluation by independent experts validated the zero guinea worm status in India.

Towards Certification of Eradication

• A National Commission for Certification of Guinea Worm Eradication was set up by the Ministry of Health and Family welfare. The Commission comprised of eight highly experienced independent experts in the field of Public Health drawn from across the country and the Director and Joint Director and Head (Helminthology) of the National Institute of Communicable Diseases. The Seventh Independent Evaluation was carried out under the guidance of the Commission in April 1999 and this validated the reported nil disease status.

• The country completed three years of guinea worm disease free period in July 1999. Subsequently, International Certification Team (ICT) from International Commission for Certification of Dracunculiasis Eradication (ICCDE), WHO visited India from 9th – 25th Nov., 1999 to assess the status of guinea worm disease in the country and to prepare a report for presentation to International Commission at Geneva.

• A meeting was organised on 8.1.2000 in Vigyan Bhawan to mark the Eradication of Guinea Worm Disease from India which was presided by Hon’ble Union Minister of State for H&FW, GOI Shri N.T. Shanmugan and Dr. Gro Harlem Brundtland, Director General, World Health Organisation, Geneva was the Chief Guest.

• The International Certification Team (ICT), presented its report on guinea worm disease status in India to the ICCDE in the meeting held in February 2000 in Geneva. On the basis of ICT report, India was declared as Guinea Worm disease free country in this meeting.

LYMPHATIC FILARIASIS

Lymphatic filariasis is a gruesome disease affecting mankind since antiquity. The disease is caused by one of the parasites Wuchereria bancrofti, Brugia malayi, or Brugia timori. The parasite is transmitted from man to man by the bite of mosquito. In India the predominant form of lymphatic filariasis is due to W. bancrofti transmitted by the Culex quinquefasciatus mosquito which breeds in sewage and in unsanitary conditions. The brugian filariasis is limited to only few pockets in India and is transmitted by the Mansonioides group of mosquitoes. Both these infections show nocturnal periodicity. The only diurnally sub-periodic variety of W brancrofti encountered in the country is confined to the aborigines of six small islands of the Nicobar. The disease in its chronic form causes a lot of physical disfigurement and disability due to obstruction of the lymphatic channels resulting in elephantiasis, hydrocoele in men and renal damage. Apart from loss in productivity during the acute attacks of lymphangitis, there is an estimated 60% loss in productivity of chronic filaria patients resulting in economic loss. The disease is now recognised as one of the major causes of DALY.

Global Burden of Lymphatic Filariasis

World wide, 120 million people are infected with filarial parasite worms and more than a billion people are at risk of the disease. The problem of lymphatic filariasis is predominant in South East Asia, Asian, Western pacific regions of WHO, East Africa, Eastern Mediterranean Region and Region of Americas. Lymphatic filariasis is a major public health problem in China, India and Indonesia. These three countries account for about two thirds of the total estimated infected persons.

Indian Scenario :

Of the 120 million people estimated to be infected throughout the globe, India contributes to around 39 percent of the global problem. According to the last estimates as of 31 December 1996, 428.28 million people living in 18 endemic states and union territories in India (315.11 million people residing in rural areas and 113.18 million residing in the urban areas) are at risk of lymphatic filariasis as depicted in table below. Of the 49 million infected individuals in India, over twenty million people suffer from chronic forms of filariasis while another 28 million are microfilaria carriers. Malayan filariasis was confined to the rural pockets in the states of Andhra Pradesh, Orissa, Madhya Pradesh, Kerala, West Bengal, Tamil Nadu and Assam.

Filaria control in India

The first pilot project in the world for the control of bancroftian filariasis was taken up in Orissa from 1949 to 1954 using three strategies:

1. Five day mass DEC therapy

2. Indoor residual spray with dieldrin 50 mg per square foot, against adult vectors in rural areas

3. Anti-larval measures (water soluble BHC powder, 6.5 gamma) in urban areas

National Filaria Control Programme

The Govt. of India launched the National Filaria Control Programme in India in 1955 under the National Institute of Communicable Diseases (NICD) after an agreement between Government of India and United States Technical Co-operation Mission for the purpose of controlling Bancroftian filariasis. The objectives NFCP were:

1. To delimit the problem, including extent of the prevalence, types of infection and their vector

2. To undertake large scale pilot studies to evaluate the known methods for filariasis control and control programme in endemic areas.

3. To train the professional and ancillary personnel required for the programme

The initial control strategies were mass therapy at a dose of 4 mgm/kg body weight per day for five consecutive days, three rounds of indoor dieldrin spray in rural areas and weekly anti larval measures in urban areas. However, the programme was withdrawn from rural areas due to poor coverage due to side effects and precipitation of resistance in bancroftian vector.

Programme review and assessment committees :

The activities of the programme were reviewed by appointed. Assessment Committees which recommended the programme modification as follows:

1st Assessment Committee 1961:

• Recurrent anti larval measures.

• Establishment of new control units in urban endemic areas.

• Adequate provision for disposal of sewage & sullage.

2nd Assessment Committee 1971:

The NFCP was again reviewed by second assessment committee and recommended as follows:

• Detection and treatment of mf carriers to compliment Anti-larval measures at weekly interval in urban areas.

• Delimitation of problem in unsurveyed districts in endemic states.

• Contiguous areas to be given priority for selecting new areas.

3rd Assessment Committee 1982:

• NFCP should be made 100 percent centrally sponsored scheme.

• In order to cover rural population, the NFCP should be integrated with Primary Health Centres. The Village Health Guide (VHG) & Multipurpose Workers (MPW) may treat clinical cases of filariasis with DEC.

• In order to support, guide & monitor the above activities a post of District Filaria Officer along with supporting staff be created in each of the endemic district.

• Filaria unit may be established in a town with minimum 20,000 people & percent mf. Rate.

• Survey unit should be engaged for resurvey of the old surveyed districts if routine survey has been completed.

• Pyrethrum extract can also be provided to NFCP towns by the centre as per Urban Malaria Scheme to stop transmission.

• B. malayi Research Unit under NICD should be made permanent.

4th Assessment Committee January, 1995:

• Project on eradication of Brugia malayi infection which is feasible may be launched in 1996.

• 100% Central Assistance for all vector borne diseases.

• Integrated vectors control for all vectors borne diseases.

• Adoption of model bye-laws for effective control of vectors in domestic situation.

• Antigen and DNA based detection of micro filarial may be adopted.

• Fresh delimitation survey in rural areas may be initiated.

• Medicated salt may be introduced in phase manner.

• Pyrethrum extract 2% can also be supplied to Filaria towns recording high malaria cases to tackle Malaria transmission.

Filaria Control & Division of Helminthology NICD:

The central organization for research and training of filariasis is in the Helminthology Division of National Institute of Communicable Diseases (NICD), Delhi and its three branches designated as the Regional Filaria Training and Research Centres (RFT&RC) located at Calicut (Kerala), Rajahmundry (Andhra pradesh) and Varanasi (Uttar Pradesh). NICD Delhi has a Central Filaria Survey Team established in 1970 which monitors the filaria transmission in selected areas in non-endemic states, Research on B.malayi filariasis is undertaken by NICD through its branch - B.malayi Research Unit located at Shertallai.

Revised Strategy for Filaria Control - Mass annual single dose DEC delivery (MDD programme).

Research in India and elsewhere have now made available more cost-effective tools for effective filaria control like annual or semi-annual mass DEC chemotherapy to the population at risk and improved management of filaria cases through foot case, hygiene and antibiotic usage and for reduction in morbidity. Recognising the availability of these new technologies the "International Task Force on Disease Eradication" has identified lymphatic filariasis as one of the six potentially eradicable diseases.

National workshop to formulate revised strategy - 1996

A national workshop to formulate a revised strategy for control of lymphatic filariasis was organised at Delhi in January 1996, wherein national & international experts recommended introduction of single annual dose DEC mass chemotherapy as a more cost-effective control strategy along with improved management of filaria patients for control of filariasis. It was proposed to administer the drug through celebrating a National Filaria Day once every year. The components of the revised control strategy are

• Single dose mass DEC therapy at a dose of 6 mg/kg body weight once a year.

• Management of acute and chronic filariasis through referral services at selective centres.

• IEC for inculcating individual/community based protective and preventive measures for filaria control.

• Continuation of anti vector measures in all the NFCP towns as a complimentary to anti-parasitic measures and the mf carriers detected in filaria clinics and elsewhere will receive standard dose of 6 mg/kg body weight per day for 12 days.

This MDD strategy was based on the hypothesis that "if majority of people in a community consume single dose of DEC annually once, it will reduce the parasite load and if continued for sufficiently long, may eliminate filariasis". The advantage of single dose mass chemotherapy for the control of filariasis are:

• The single day regime is as effective as 12 day regime as a public health measure.

• It has lower side effects thereby facilitating better public compliance.

• It involves decreased delivery costs.

• It does not require complex management infrastructure.

• It can be integrated into the existing primary health care system for delivery compliance.

• Single dose mass therapy in combination with other techniques has already eliminated lymphatic filariasis from Japan, Taiwan, South Korea and Solomon Island and DEC mass therapy is much safer in India in the absence of Onchocerciasis and Loiasis infection.

Pilot project for MDD

In 1996 Govt. of India started a pilot project of annual mass DEC chemotherapy through celebration of National Filaria Day in 13 districts in the first year and then increasing in phased manner to cover a population of 200 million by 5 years. The MDD is planned for a period of five years since the fecundic life span of the parasite is about 5 years. The Pilot project has been started in 13 districts since 1997. The states and district undertaken for MDD since 1997 are listed below:

MDD Pilot Project areas - Since 1997.

WHO resolution for filarial elimination

WHO has initiated filariasis elimination programme world wide with the passage of a resolution in May 1997 by 50^th World Health Assembly, calling for "the elimination of lymphatic filariasis as a public health problem".

Filaria control research activities of the division :

• Study to enhance compliance during MDD - Community-directed treatment of lymphatic filariasis

Evaluation of the DEC coverage & compliance during MDD, from 1996 to 1998 through health services indicated that only half of the targeted population have actually consumed the drug. Thus principle challenge facing the programme is to increase coverage of population and ensure sustained interest over 5-8 years to achieve near elimination of carrier state in the community. Success of ivermectin distribution through community directed strategy in onchocersiasis prompted WHO to start a project on community directed treatment for control of lymphatic filariasis to develop effective and sustainable large scale treatment method for endemic communities initiated and supported by health services.

In light of above a Multi-centric study of community-directed of lymphatic filariasis undertaken in the country in which the NICD and ICMR participated. The objectives of this study were to develop effective and practical methods for sustainable annual mass treatment of lymphatic filariasis which will facilitated the global elimination of lymphatic filariasis as the public health problem. The result of the study varied from site to site. However, as against the African experience, where ComDT was successful, Indian experience was by and large not satisfactory. The final recommendations were that a combination of the health care delivery by health system with community involvement is be best suited to Indian needs.

• Study for impact and operational feasibility - Co administration of Albendazole and DEC

A multicentric study is being undertaken in the country to study the operational feasibility and impact of co-administration of Albendazole and DEC in the country. About 20 million population in 9 districts of the states of Tamil Nadu, Kerala and Orissa will be taken for the study. Indian Council of Medical Research and NICD are collaborating in this study.

Morbidity Management

Morbidity management facility has been established at three NICD branches at Varanasi, Calicut and Rajahamundry. A protocol was developed to study the operational feasibility and outcome of the intervention. A study to this effect has been started wef 2^nd Oct. 2000 at these sites.

INTESTINAL PARASITIC INFECTIONS IN INDIA :

World Health Organisation (WHO) estimates that one fourth of the world’s population is chronically infected with soil transmitted helminths including at least 400 million school age children. The intensity and prevalence can vary considerably in different regions depending upon the climatic conditions, type of soil, sanitary conditions and food and personal hygiene. High prevalence of intestinal parasite infections is closely correlated with poverty, poor environmental hygiene and impoverished health services. Intestinal parasitic infections are widespread and highly prevalent but also relatively easy to control. The magnitude of the problem in India is not well documented.

Surveys undertaken during 1968-1998

Division of Helminthology in the National Institute of Communicable diseases, Delhi has been undertaking conventional surveys in the various parts of the country since 1968 to assess the magnitude of problem and to suggest the appropriate control interventions. These surveys were planned in co-ordination with the respective state/district health officials in the high-risk localities of the survey areas. A total of 110 surveys have been undertaken in various states of the country.

Since 1990 a total of 16 surveys have been undertaken in 14 states. Prevalence of the intestinal parasitic infections was found to vary from 22.8% in Puri district, Orissa to 78% in urban slum localities of Calcutta, West Bengal.

Use of kato katz technique for stool testing:

During the period 1998 to 2000 surveys to assess the problem of soil transmitted helminths only by using WHO methodology of sampling and laboratory examination (1998 WHO publication WHO/CTD/SIP/98.1 on “Guidelines for the evaluation of soil-transmitted helminthiasis and shistosomiasis at community level”). Before starting of the surveys a two day workshop on the survey of Soil Transmitted Helminths was organised at NICD from 2^nd to 4^th February, 1999. State Epidemiologist, district nodal officer and microbiologist/ pathologist of the five states/districts selected for the study participated in the workshop and developed plan of action for the surveys.

Surveys were undertaken in ecologically homogeneous zones in children in 9-10 year age group; as this is representative of the situation in the whole community which can be used to assess the need of control measures.

A total of 3837 samples were collected from 96 schools in 7 ecological regions/zones (4 urban, 6 rural and 1 each from tribal and non – tribal communities). Examination by the Kato-Katz technique revealed that the prevalence of soil transmitted helminths was maximum 39.7% in urban community of district Chitradurga, Karnataka. Prevalence of Ascaris lumbricoides was highest (39.2%) in Chitradurga followed by 30.7% in Gangtok, Sikkim, Ankylostoma Deudonale was detected in 6.6% in rural community of Alwar district, Rajasthan. Maximum prevalence of Tricuris Trichuria was detected in coastal zone of Alapphuza, Kerala (21.5%). Lowest 0% prevalence of the soil-transmitted helminths was observed in the desert zone of Jodhpur, Rajasthan. Detail observations are shown in TABLE –1&2.

Table-1

Ecological Zone wise Prevalence of Soil transmitted helminths (WHO methodology) – 1998 to 2000

STH - Soil transmitted helminths, R - Rural zone, U - Urban zone, T - Total, AL - Ascaris lumbricoides, HW - Hookworm and TT - Trichuris Trichuria

Table-2 Prevalence of Ascaris lumbricoides, hookworm and Trichuris in the survey zones was as follows:-

R- Rural zone, U - Urban zone, T - Total, AL - Ascaris lumbricoides, HW - Hookworm and TT - Trichuris Trichuria

RESEARCH - Studies being undertaken currently by the division and branches

1. Entomological surveillance of vector borne diseases in Alappuzha district.

2. Multicentric study on operational feasibility and impact of CO-administration of albendazole and DEC in controlling lymphatic filariasis in Alappuzha and Calicut districts of Kerala state.

3. To develop lymphoedema management facility at NICD branches and study the operational feasibility.

4. Studies on the susceptibility status of mosquito larvae to the community used larvicides in Kerala.

5. Studies on the susceptibility status of mosquito vectors of diseases to various insecticides in Kerala State.

6. Studies on the surveillance of Aedes species of mosquitoes in Kerala State.

7. Studies on the effect of DEC on microfilaria carriers - biochemical and parasitological aspects.

VARANASI

1. Kala-azar endemicity status in Varanasi District.

2. Persistence of Vibrio cholerae in inter epidemic period.

3. Water quality monitoring of drinking water in Varanasi city.

4. Research on advocacy for sustained treatment for compliance in Lymphatic filariasis control in Varanasi District.

5. Study of operational feasibility and impact in Lymphedema management facility at Varanasi Branch.

6. Strategy for effective delivery of drugs for lymphatic filariasis control in urban areas of Varanasi district.

7. Incidence of a symptomatic microscopic heamaturia among endemic healthy persons and filarial patients in the district of Varanasi.

RAJAHMUNDRY

1. A study on the Comparative efficacy of ELISA, ICT and night blood smear microscopy for diagnosis of filariasis - August, 2000.

2. A study on the prevalence of malaria in Rajamundry town of Andhra Pradesh - March, 2000.

3. Biosystematic studies on the Culicidae (Dipera:Nematocera) of India-A multicentric study by the Divn.of Med.Ebt. & Vector Control, N.I.C.D., Delhi- November, 2000.

4. Development of Lymphedema management facility at NICD Branches and study the operational feasibility - October, 2000.