Filariasis
Filariasis, while not causing fatalities, poses a significant public health concern for the following reasons:
Problem Statement: It is approximated that a total of 751 million individuals worldwide are susceptible to filariasis, with half of these residing in India. Uttar Pradesh exhibits the highest disease rate, followed by Bihar, Kerala, Orissa, Andhra Pradesh, and Tamil Nadu. Uttar Pradesh and Bihar collectively contribute to two-thirds of all reported cases in India. Over the past three decades, bancroftian filariasis has expanded to new regions, accompanied by an escalation in the intensity of infection.
The major reasons for this phenomenal increase are:
- Expansion of filaria surveys to districts that were previously unexamined.
- Natural population growth in regions where filaria is prevalent.
- Migration of sizable population segments to non-affected areas in pursuit of employment.
- Establishment of transmission potential in new regions.
- Extensive developmental and construction activities in urban areas creating breeding grounds for vectors.
Question for National Filaria Control Program
Try yourself:
What are the major reasons for the increase in filariasis cases?Explanation
- The passage states that one of the major reasons for the increase in filariasis cases is the migration of sizable population segments to non-affected areas in pursuit of employment.
- This means that people from regions with a high prevalence of filariasis are moving to areas where the disease is not common.
- As a result, they may unknowingly carry the infection with them and introduce it to new regions.
- This migration contributes to the expansion of filariasis to new areas and an escalation in the intensity of infection.
- It is important to address this issue by raising awareness about filariasis and implementing preventive measures in both affected and non-affected areas to control the spread of the disease.
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Filariasis-Control Measures
Control Measures for Host (Human):
- Ensure the body is adequately covered.
- Utilize insecticide-treated mosquito nets.
- Install wire gauze doors to block the entry of mosquitoes into the house.
- Apply mosquito repellents (such as citronella oil, DMP cream, permethrin) on exposed skin.
- Employ residual spray with pyrethrum and rotenone.
- Use swatters.
- Implement electronic repellents.
Control Measures-Agent (Microfilaria Control)
Individual Treatment (DEC):
- Utilization of antiparasitic drugs (DEC - Diethylcarbamazine, IVERMECTIN).
- The generally accepted dose of DEC for the treatment of Bancroftian filariasis is 6 mg/kg body weight per day orally for 12 days, preferably administered in divided doses after meals. This results in a total of 72 mg of DEC per kg of body weight for a complete treatment. For Brugian filariasis, recommended doses vary from 3 to 6 mg of DEC/kg body weight per day, totaling 36-72 mg DEC/kg body weight for a complete treatment. Note: In endemic areas, treatment must be repeated at specified intervals, typically every 2 years.
Mass therapy (DEC)-National Filaria day:
In this strategy, DEC is administered to nearly all individuals in the community, regardless of whether they exhibit microfilaraemia, disease symptoms, or show no signs of infection, with the exception of children under 2 years, pregnant women, and severely ill patients. The recommended dose is 6 mg/kg of body weight.
Control Measures-Agent (Microfilaria Control)
DEC Salt
- The use of DEC-medicated salt is a special form of mass treatment using very low doses of the drug over a long period of time.
- Common salt medicated with 1-4 g of DEC per kg has been used for filariasis control in some endemic areas of W. bancrofti and B. malayi, particularly after an initial reduction in prevalence has been achieved by mass or selective treatment of Mf carriers.
- Treatment should be continued for at least 6 to 9 months.
In the Lakshadweep islands, this regimen has been shown to be safe, cheap and effective.
Ivermecting: Not Used In India
Control measures (Vector)
Antilarval:(a) Use of organic oils - Biodegradable malarial larvicidal oil.
(b) Deployment of floating layers comprising non-biodegradable polystyrene beads.
Antiadult:
Mahathion - Organophosphates
Environmental Control:
Prevention of vector breeding sites
(a) Establishment of soakage pits in villages.
(b) Implementation of well-constructed surface drainage systems in small towns.
(c) Installation of closed underground drainage systems in larger towns.
(d) Eradication of aquatic plants.
Question for National Filaria Control Program
Try yourself:
What is one control measure for filariasis that involves the use of insecticide-treated mosquito nets?Explanation
- One control measure for filariasis is the use of insecticide-treated mosquito nets.
- These nets are designed to repel and kill mosquitoes, preventing them from biting humans and transmitting the filarial parasites.
- The insecticide on the nets helps to eliminate mosquitoes that come into contact with it, reducing the risk of infection.
- This control measure is effective in areas where mosquitoes are prevalent and can significantly reduce the transmission of filariasis.
- It is important to ensure that the nets are properly treated and used consistently to maximize their effectiveness.
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Filariasis-Control Measures
The objective of the National Health Policy 2012 was to eliminate filaria from India by 2015, but the deadline has now been extended to 2020. The global strategy for eliminating the disease involves mass drug administration in endemic regions, ensuring coverage of over 65% of the population.
The elimination of lymphatic filariasis is defined as the point when it ceases to be a public health problem, marked by a reduction in the number of microfilaria carriers to less than 1%, and children born after the initiation of the Elimination of Lymphatic Filariasis (ELF) are free from circulating antigenaemia (presence of adult filaria worms in the human body).
Strategy for the Elimination of Lymphatic Filariasis:
- Implementing Annual Mass Drug Administration (MDA) with a single dose of DEC (Diethylcarbamazine citrate) and Albendazole for a minimum of 5 years or more to the entire population at risk (excluding pregnant women, children below 2 years of age, and seriously ill individuals) to interrupt the transmission of the disease.
- Conducting home-based management of lymphoedema cases and scaling up hydrocele operations in identified Community Health Centers (CHCs), district hospitals, and medical colleges.
National Filaria Control Program
- Established in 1955, the National Filaria Control Programme (NFCP) has been in operation. In June 1978, the operational component of the NFCP was merged with the Urban Malaria Scheme to maximize the utilization of available resources. The training and research components, however, continue to be under the direction of the National Institute of Communicable Diseases, Delhi.
- The implementation of the National Filaria Control Programme involves 206 filaria control units, 199 filarial clinics, and 27 survey units, primarily focusing on endemic urban towns. In rural areas, anti-filaria medicines and morbidity management services are delivered through the primary health care system.
- Microfilaria surveys are conducted in all implementation units through night blood surveys before Mass Drug Administration (MDA). The survey includes 4 sentinel and 4 random sites, collecting a total of 4000 slides (500 from each site).
Question for National Filaria Control Program
Try yourself:
What is the objective of the National Health Policy 2012 regarding filariasis in India?Explanation
- The objective of the National Health Policy 2012 was to eliminate filariasis from India by 2015, but the deadline has now been extended to 2020.
- The global strategy for eliminating the disease involves mass drug administration in endemic regions, ensuring coverage of over 65% of the population.
- Therefore, the objective of the National Health Policy 2012 is to control the spread of filariasis in India by 2020.
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Filaria-Repeats
- List the causative organisms and vectors of lymphatic filariasis in India. What are its salient control measures (2009)?