EPIDEMIOLOGY OF FILARIASIS

1. LYMPHATIC
FILARIASIS
DR. MAHESWARI JAIKUMAR

2. NATIONAL FILARIA
CONTROL PROGRAMME
(NFCP) IN INDIA

3. • Filariasis is caused by several round,
coiled and thread-like parasitic
worms belonging to the family
filariea.These parasites after getting
deposited on skin penetrate on their
own or through the opening created
by mosquito bites to reach the
lymphatic system.

4. • The disease is caused by the
nematode worm,
either Wuchereria
bancrofti or Brugia malayi
• Is transmitted by ubiquitous
mosquitospeciesCulex quinquefasci
atus & Mansonia annulifera/M.uni
formis respectively.

5. • BRUGIAN FILARIASIS: Lymphadenitis
(swollen and painful lymphnode)
occurs episodically, most commonly
affecting one inguinal lymph node at a
time. The infection lasts for several
days and usually heals spontaneously.
The frequency of episodes may vary
from 1-2 attacks per year to several
attacks per month.

6. • Sometimes lymphadenitis is followed
by a characteristic retrograde
lymphangitis. The infection may
spread to the surrounding tissues,
and occasionally involves the whole
thigh or entire limb. The infected
lymph node may become an abscess,
ulcerate, and heal with fibrotic
scarring.

7. • The acute clinical course with its
complications may last from several
weeks to 3 months.
Characteristically, elephantiasis
involves the leg below the knee but
occasionally it affects the arm below
the elbow. Genital lesions or chyluria
(milky colour urine) do not occur in
brugian filariasis.

8. BANCROFTIAN FILARIASIS:
• The lymphatic vessels of the male
genitalia are most commonly affected in
bancroftian filariasis, producing episodic
funiculitis (inflammation of the spermatic
cord), epididymitis and orchitis.
• Adenolymphangitis of the extremities is
less common. Hydrocele is the most
common sign of chronic bancroftian
filariasis, followed by lymphoedema,
elephantiasis and chyluria.

9. LYMPHATIC FILARIASIS (LF)

10. • commonly known as elephantiasis is a
disfiguring and disabling disease, usually
acquired in childhood. In the early stages,
there are either no symptoms or non-
specific symptoms.
• Although there are no outward
symptoms, the lymphatic system is
damaged. This stage can last for several
years. Infected persons sustain the
transmission of the disease.

11. • Due to damaged lymphatic system,
patients with lymphoedema have
frequent attacks of infection causing
high fever and severe pain. Patients may
be bed-ridden for several days and
normal routine activities become
difficult.
• Such attacks not only cause acute
physical suffering but also directly
impede the earning capacity of the
individual.

12. FILARIA VECTORS

13. • C.quinquefasciatus is the vector
of W.bancrofti in the mainland.
• C.quinquefasciatus breeds in
association with human habitations
and is the domestic pest
mosquitoes, preferring polluted
waters, such as sewage and sullage
water collections including cess
pools, cess pits, drains and septic
tanks.

14. • The eggs are laid in rafts containing
150-40 eggs each depending on
quality and quantity of blood meal
taken.
• At the optimum temperature of 250
C to 300 C, the eggs hatch within 24
to 48 hours.

15. TRANSMISSION OF LYMPHATIC
FILARIASIS
•
The adult produces millions of very
small immature larvae known as
microfilariae, which circulate in the
peripheral blood with marked
nocturnal periodicity.
• The worms usually live and produce
microfilariae for 5-8 years.

16. ADULT FILARIAL WORMS
(MACROFILARIAE) INHABITING LYMP
HATIC SYSTEM OF MAN

17. • Lymphatic filariasis is transmitted through
mosquito bites.
•
The persons having circulating
microfilariae are outwardly healthy but
transmit the infection to others through
mosquitoes.
The persons with chronic filarial swellings
suffer severely from the disease but no
longer transmit the infection.

18. LIFE CYCLE OF FILARIA PARASITE

19. MAGNITUDE OF DISEASE
• Cases of filariasis have been recorded
from Andhra Pradesh, Assam, Bihar,
Chhattisgarh, Goa, Jharkhand,
Karnataka, Gujarat, Kerala, Madhya
Pradesh, Maharashtra, Orissa, Tamil
Nadu, Uttar Pradesh, West Bengal,
Pondicherry, Andaman & Nicobar
Islands, Daman & Diu, Dadra & Nagar
Haveli and Lakshadweep.

20. FILARIA ENDEMIC DISTRICTS

21. NATIONAL FILARIA
CONTROL PROGRAMME
(NFCP)

22. • After pilot project in Orissa from
1949 to 1954, the National Filaria
Control Programme (NFCP) was
launched in the country in 1955
with the objective of delimiting the
problem, to undertake control
measures in endemic areas and to
train personnel to man the
programme.

23. • The main control measures were
mass DEC administration, antilarval
measures in urban areas and indoor
residual spray in rural areas. The
NFCP set-up and population
protected are given in the table
below:

24. STRATEGY
• Recurrent anti-larval measures at
weekly intervals.
• Environmental methods including
source reduction by filling ditches,
pits, low lying areas, deweeding,
desilting, etc.

25. • Biological control of mosquito
breeding through larvivorous fish.
• Anti-parasitic measures through
'detection' and 'treatment' of
microfilaria carriers and disease
person with DEC by Filaria Clinics in
towns covered under the
programme.

26. REVISED STRATEGY
• Annual Mass Drug
Administration with single dose of
DEC was taken up as a pilot project
covering 41 million population in
1996-97 and extended to 74 million
population.

27. • This strategy was to be continued
for 5 years or more to the
population excluding children below
two years, pregnant women and
seriously ill persons in affected
areas to interrupt transmission of
disease.

29. MORBIDITY MANAGEMENT

30. • Home based management of
lymphoedema cases and
- up-scaling of hydrocele operations
in the identified CHCs / District
hospitals/ medical colleges.

31. NATIONAL GOAL
The National Health Policy 2002
aims at Elimination of Lymphatic
Filariasis by 2015.

32. STRATEGY FOR ELIMINCATION OF
LYMPHATIC FILARIASIS
• The strategy for achieving the goal of
elimination is by Annual Mass Drug
Administration of Anti Filarial Drugs
(DEC+Albendazole) for 5 years or more to
the population excluding children below
two years, pregnant women and seriously
ill persons in affected areas to interrupt
transmission of disease.
•

33. • Home based management of cases
who already have the disease and
hydrocelectomy operations in
identified CHCs and hospitals.

34. MDA - 2004
• Mass Drug Administration of single dose
of DEC was launched as National Filaria
Day (NFD) on 5th June 2004 by Dr. A.
Ramadoss, Hon'ble Union Minister for
Health & Family Welfare in Thane
district in Maharashtra . Smt. P. Lakshmi,
Hon'ble Union Minister of State for
Health & Family Welfare initiated the
MDA in Raibareilly district in Uttar
Pradesh.