Filariasis, also known as elephantiasis, is a tropical disease caused by parasitic roundworms that dwell in the blood and tissues of humans. The most common type is lymphatic filariasis, which is caused by infection with Wuchereria bancrofti or Brugia malayi parasites transmitted via mosquitoes. Over 1 billion people worldwide are at risk of infection, with symptoms ranging from asymptomatic microfilaremia to acute adenolymphangitis episodes to chronic manifestations like elephantiasis and hydrocele. Diagnosis involves blood tests detecting microfilariae or antibodies, ultrasound detecting adult worms, and treatment primarily consists of diethylcarbamazine or doxycycline to kill the parasites

1. Filariasis
Garima Thakur

2. ► Commonly known as Elephantiasis.
► It is a tropical disease.
► Caused by parasitic worm Filariae. Filariae is a microscopic roundworm that dwells in the
blood and tissues of humans.
► Most common or important filarial disease is lymphatic filariasis.

3. History
► There is no reliable written record of lymphatic filariasis before 16th
century
► It has been known to occur in Nile region. During Egyptian
civilization, a statue of Pharaoh Mentuhotep depicts swollen limbs,
surveys from nok civilization in west Africa depicted scrotal
swelling.
► First written account comes from the ancient Greek and Roman
civilization.
► Writer were able to differentiate between leprosy (Elephantiasis
graecorum) and lymphatic filariasis (Elephantiasis arabum)
• The first reliable documentation of lymphatic filariasis symptoms did not
occur until an exploration of Goa between 1588 and 1592.

4. Causative
agent
► Caused by infection with parasites-
► Wuchereria bancrofti- responsible for 90%
cases.
► Brugia malayi- responsible for 0.6% cases.
TRANSMIT BY
• Culex fatigans transmit nocturnal Wuchereria bancrofti
• Aedes polynesiensis transmit diurnal Wuchereria bancroti
• Mansonia annulifera and Mansonia uniformis transmit Brugia
malayi

7. Occurrence of
filariasis
► Currently, more than 1.4 billion people in 83 countries are at risk of
infection.
► Approx. 80% of these people are living in 10 countries.
► Bangladesh, Democratic republic of Congo, Ethiopia, India, Indonesia,
Myanmar, Nigeria, Nepal, Philippines, and the united republic of
Tanzania.
► 25 million men suffers with genital disease.
► In 2018, 893 million people in 49 countries were living in areas that
require preventive chemotherapy to stop the spread of infection.
► Eliminating lymphatic filariasis can prevent unnecessary suffering and
contribute to reduce poverty (WHO March 2014)

8. Indian scenario ► Indian cases have been reported from about 250 districts.
► Estimate in 2001 indicates that about 473 million people are
exposed to the risk of backroftian infection.
► 125 million people lives in urban areas,
► 348 million people lives in rural areas.
► About 31 million people are estimated to be harboring
microfilariae.
Wuchereria backroft-
• Bihar- highest endemicity 17%
• Kerala- 15.7%
• U.P- 14.6%
• Andhra Pradesh- 10%
• Tamil Nadu- 10%
• Goa- 1%
• Lakashdeep- 1.8%
• Madhya Pradesh- 3%
• Assam- 5%
B. malayi
• Kerala with highest no. of
infection.
• Tamil nadu
• Andhra Pradesh
• Orissa
• Madhya Pradesh
• Assam
• West Bengal
( single largest tract of infection
lies among the kerala and
infection in other states is
confined to few villages )

10. Life cycle: Digenetic (2hosts)
Definitive host: man (no animal host)
Intermediate host: Female mosquitos (belong to genus -Culex, Aedes and
Anopheles).
Infective form: Actively motile third stage Filariform larva is infective to man.
Mode of transmission:Humans get infection by the bite of mosquito carrying a
Filariform larva.
Copulation-Copulation takes place when the individual of both sexes are present
in the same lymp gland

11. Host
► Man is a natural host.
► Age- all ages are susceptible.
► Gender- male > female. Ratio is 10:1
► Immunity develop after many years of exposure.
► Social factors- urbanization, industrialization, migration, illiteracy,
poverty, poor sanitation.
► Reservoir- leaf monkeys, macaques in some part of the world.
► Intermediate host- Mosquito.
ENVIRONMENT
AL FACTORS
• Climate favoring vector.
70% relative humidity.
poor drainage, poor sewage disposal, lack of town planning.
common breeding places- cesspool, soakage pits, ill maintained drains,
septic
tanks , open ditches.

12. MODE OF TRANSMISSION
► Transmitted by the bite of the
infected vector mosquito.
► Parasite after deposited on skin
parasite on their own or through
the opening creates by mosquito
bite to reach the lymphatic system.
► Dynamics of transmission depend
on the infective biting rate.
► From mosquito bite to clinical
manifestation is 8-16 months.
INCUBATION PERIOD
• 90% of cases with chronic manifestation will give rise a history of acute attacks . Occasionally the adult worms and
their associated granulomatous reaction are manifested as lumps in subcutaneous tissue, breasts and testicles.
• Maximum density of microfilaria in blood is 10p.m to 2a.m.

14. SYMPTOMS
Asymptomatic
Microfilariasis
• Many infected area,
many infected individuas
do not exhibit symptoms
of filarial infection.
• These people have
downregulated TH1 cells
response (Low IFN
gamma) and elevated
TH2 cells response (IL-
4).
Acute Filariasis (Acute
adenolymphangitis)
• It is characterized by recurrent episodes of
Filarial Fever( high grade fever)
• Lymphatic inflammation( lymphangnitis and
lymphodenitis)
I. Lower extremities are more commonly
affected than the upper limbs.
II. Lymphatics of the male genital organs
are frequently involved that leads to
funiculitis, epididymitis and orchitis ( not
seen in burgian filariasis)
III. Transient Local Edema- Early pitting
edema, reversible on limb elevation
IV. Dermatolymphangitis- Plaque like lesion
is formed over the affected skin with
fever, chill and lymphatic inflammation.
V. In burgian filariasis episodes are more
frequent and abrupt in oneset.
Chronic Filariasis
( Develops 10-15 years
of infection)
Chronic host IR against dead worm leads to
enhanced granuloma, Thrombi formation and
fibrosis of the lymph vessels.
The manifestation in descending order of
occurrence are:
1) HYDROCELE ( MOST COMMON MANIFESTATION
Accumulation of straw coloured fluid in the cavity of
tunica vaginalis of testis
Elephantiasis( swelling of lower limb or less commonly
arm, vulva or breast)
Chronic funiculitis and epididymitis.
2) CHYLURIA – Excretion of chyle ( a milky white fluid
in urine may occur rarely).
More pronounced in the morning or after fatty meal.
This is due to rupture of lymph vessels into the urinary
system.

15. DIAGNOSIS
► 1) Blood eosinophilia( absolute eosinophil count more than
3000/micro litre).
► 2) Chest X- Ray : Can detect dead and calcified worm
• Elevated serum Ig E levels
• Pul,monary function test shows obstructive changes in lungs.
3) ULTRASOUND : High frequency ultrasound with doppler
techniques are employed to detect.
 Can detect anatomical abnormalities of lymhatics.
 Filarial Dance sign- Serpentine movement of adult worms within the
Lymphatic vessels of scrotum.

16. TREATMENT
1) DEC( Diethylcarbamazine): 4-6mg/kg for 14 days, Relapse may occur in 12-25
% cases.
► This drug kills the microfilariae and some of the adult worms
► DEC+Ivermectin – Another way to treat elephantiasis. Taken once a year and
the combination has better long term results.
2) DOXYCYCLIN: Targets the intracellular endosymbiont, Wolbaschia .
It is an alternative first line antifilarial Therapy for adults and children > 8 years of
age with lymphatic filariasis.
Has effect on adult worm.

17. PREVENTION
1) Antilarval Measures: Highly expensive and hence mainly restricted to
urban areas. Chemicals used are Mosquito larvicidal oil, Pyrethrum- Based oil(
Pyrosene oil- E) etc.
2) Antiadult Measures: Antiadult measures like Pyrethrum spray can be used.
DDt and Hexachlorocyclohexane (HCH) are not effective.
3) National Vector Borne Disease Control Program : National filariasis control
Program in India is active since 1955, whicj was integrated with National Vector
borne disease control Programme in 2006.