Lymphatic filariasis is caused by parasitic roundworms Wuchereria bancrofti and Brugia malayi, which are transmitted by mosquitoes and can cause elephantiasis. The worms live in the lymphatic system and can cause severe swelling of the limbs and genitals. Over 120 million people are infected globally in tropical areas. Treatment involves drugs to kill the adult worms and microfilariae like diethylcarbamazine, ivermectin and albendazole. Mass drug administration programs combined with mosquito control can eliminate the disease from an area.

1. Lymphatic
Filariasis /
Elephantiasis
Wuchereria bancrofti
& Brugia malayi

2. What is it?
 Wuchereria bancrofti and Brugia malayi
are filarial nematodes
 Spread by several species of night -
feeding mosquitoes
 Causes lymphatic filariasis, also known
as Elephantiasis
 Commonly and incorrectly referred to as
“Elephantitis”

3. +
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4. Definitive Host
 Humans are the definitive
host for the worms that
cause lymphatic filariasis
 There are no known
reservoirs for W.bancrofti.
 B.malayi has been found in
macaques, leaf monkeys,
cats and civet cats

5. Elephantiasis
 A Debilitating disease.
 Abnormal accumulation of
watery fluid in the tissues
causing severe swelling.
 Skin usually develops a
thickened, pebbly
appearance and may
become ulcerated and
darkened

6. Intermediate Host
 W.bancrofti is transmitted by
Culex, Aedes, and Anopheles
species
 B.malayi is transmitted by
Anopheles and Mansonia species.
Anopheles
Aedes
Culex
Mansonia

7. Geographic Range
 Lymphatic filariasis occurs in the tropics of
India, Africa, Southern Asia, the Pacific,
and Central and South America.

8. Terms to Know
 Elephantiasis: is a disease that is
characterized by the thickening of the skin and
underlying tissues, especially in the legs and
genitals.
 Filariasis: is a parasitic disease caused by
roundworms
 Lymph Edema: Is a condition of localized
fluid retention caused by a compromised
lymphatic system.

9.  Brugia malayi: a causative agent of human
lymphatic filariasis leading to lymph edema and
swelling of the legs
 Genome: a complete DNA sequence of one set
of chromosomes.

10. Lymphatic Filariasis by the
numbers
 Endemic in 83 countries
 1.2 billion at risk
 More than 120 million people infected
 More than 25 million men suffer from
genital symptoms
 More than 15 million people suffer from
lymphoedema or elephantiasis of the leg

11. Morphology - W.bancrofti
 W.bancrofti is a sexually
dimorphic species.
 The adult male worm is long and
slender, between four and five
centimeters in length, a tenth of a
centimeter in diameter, and has a
curved tail.
 The female is six to ten
centimeters long, and three times
larger in diameter than the male.
 Microfilariae are sheathed, and
approximately 245 to 300 µm in
length.

12. Morphology - B.malayi
 B.malayi microfilariae are slightly
smaller than those of W.bancrofti.
 Microfilariae are sheathed, and
about 200 to 275 µm.
 Not much is known about the adult
worms, as they are not often
recovered
 One distinctive feature of B.malayi
is that the microfilarial nuclei
extends to the tip of the tail

13. Wuchereria Life Cycle

15. Symptoms
 1. Asymptomatic: patients have hidden
damage to the lymphatic system and kidneys.
 2. Acute: attacks of ‘filarial fever’ (pain and
inflammation of lymph nodes and ducts, often
accompanied by fever, nausea and vomiting)
increase with severity of chronic disease.
 3. Chronic: may cause elephantiasis and
hydrocoele (swelling of the scrotum) in males
or enlarged breasts in females.

16. Diagnosis
 The standard method for diagnosing active
infection is the identification of microfilariae by
microscopic examination
 However, microfilariae circulate nocturnally,
making blood collection an issue
 A “card test” for parasite antigens requring only a
small amount of blood has been developed
 Does not require laboratory equipment
 Blood drawn by finger stick

17.  The table below shows how the symptoms are graded by
severity of the swelling – known as a lymphœdema.
These swellings usually occur in the legs, breast tissue
and groin.

18. Control
 As with malaria, the most effective method
of controlling the spread of W.bancrofti and
B.malayi is to avoid mosquito bites
 The CDC recommends that anyone in at-
risk areas:
 Sleep under a bed net
 Wear long sleeves and trousers
 Wear insect repellent on exposed skin, especially
at night

19. Vector control
 Covering water-storage containers and
improving waste-water and solid-waste
treatment systems can help by reducing the
amount of standing water in which
mosquitoes can lay eggs.
 Killing eggs (oviciding) and killing or
disrupting larva (larviciding) in bodies of
stagnant water can further reduce mosquito
populations.

20. Treatment
 Treatment of filariasis involves two
components:
 Getting rid of the microfilariae in people's
blood
 Maintaining careful hygiene in infected
persons to reduce the incidence and
severity of secondary (e.g., bacterial)
infections.

21. Drugs, Drugs, Drugs!
 Anti-filariasis medicines commonly used include:
 Diethylcarbamazine (DEC)
 reduces microfilariae concentrations
 kills adult worms
 Albendazole
 kills adult worms
 Ivermectin
 kills the microfilariae produced by adult worms

22. …And more drugs!
 The disease is usually treated with single-
dose regimens of a combination of two
drugs, one targeting microfilariae and one
targeting adult worms (i.e.,either
diethylcarbamazine and albenadazole, or
ivermectin and albendazole
 In some areas, DEC laced table salt is used
as a prophylactic

23. Treatment 2: Manchester United 0
 If a high enough coverage of anti-filariasis drug
treatment can be achieved (treating greater than
80% of the people in a community), the disease
can be eradicated from an area.
 Attempts to eliminate the disease are being
helped considerably by Merck and Co., which is
donating ivermectin to treatment efforts, and
Smith Kline Beecham, which is donating
albendazole.
 The Gates Foundation has also donated millions
towards eliminating lymphatic filariasis

24. Elimination programs

25. Finally…
 http://youtube.com/watch?v=SkIryQ6Paqg