Nematode parasite of man

1. Wuchereria bancrofti
Prepared by: Ron Louise B. Salomon

2. TAXONOMY
• Domain: Eukaryota
• Kingdom: Metazoa
• Phylum: Nematoda
• Class: Secernentea
• Order: Spirurida
• Family: Filariidae
• Genus: Wuchereria
• Species: bancrofti

3. GEOGRAPHICAL
DISTIBUTION
• Lymphatic filariasis affects over 120
million people in 73 countries throughout
the tropics and sub-tropics of Asia, Africa,
the Western Pacific, and parts of the
Caribbean and South America.

4. GEOGRAPHICAL
DISTIBUTION
• In the Americas, only four countries are currently
known to be endemic: Haiti, the Dominican
Republic, Guyana and Brazil.
• In the United States, Charleston, South Carolina,
was the last known place with lymphatic filariasis.
The infection disappeared early in the 20th
century. Currently, you cannot get infected in the
U.S.

5. GEOGRAPHICAL
DISTRIBUTION
• In the Philippines, it can be found in:
1. Camarines Norte, Sur
2. Albay, Sorsogon, Mindoro, Masbate,
Romblon, Marinduque
3. Bohol, Samar, Leyte, Palawan
4. Mountain Provinces
5. All provinces of Mindanao

6. MORPHOLOGY OF STAGES
A. MICROFILARIA
The embryo itself averages
290 μm by 6-7 μm, though
the sheath surrounding it
is slightly larger. The
cuticle of the embryo has
well-marked striations and
the tail tapers gradually to
a rounded tip.

7. MORPHOLOGY OF STAGES

8. MORPHOLOGY OF STAGES
• B. INFECTIVE (3RD STAGE) LARVA
The head of the infective larva is truncate-conic,
trapezoidal when viewed laterally. The oral
aperture is circular with prominent papillae
ringing the outer edge. The tail is blunt with three
caudal papillae, two latero-ventral and one dorso-terminal.
In females the tail is relatively longer. As
the larva grows the head loses its truncate shape
and is well rounded by the time it develops into a
4th stage larva.

9. MORPHOLOGY OF STAGES

10. MORPHOLOGY OF STAGES
• C. ADULT
A translucent white worm with a
smooth cuticle. The head is
rounded and separated from the
body by a neck-like
constriction. In females the tail
tapers gradually and is rounded
at the tip, while in males the tail
curves ventrally. Males and
females live coiled together.
Females vary in length from 30-
100 mm with a diameter
ranging from 100-300 μm.
Males are smaller, typically half
the size of females.

11. LIFE CYCLE

12. DISEASES AND SYMPTOMS
Lymphatic Filariasis
is a parasitic disease caused
by microscopic, thread-like
worms. The adult
worms only live in the
human lymph system. The
lymph system maintains
the body's fluid balance
and fights infections.

13. DISEASES AND SYMPTOMS
• The disease spreads from person to person by mosquito
bites. When a mosquito bites a person who has lymphatic
filariasis, microscopic worms circulating in the person's
blood enter and infect the mosquito. People get lymphatic
filariasis from the bite of an infected mosquito. The
microscopic worms pass from the mosquito through the
skin, and travel to the lymph vessels. In the lymph vessels
they grow into adults. An adult worm lives for about 5–7
years. The adult worms mate and release millions of
microscopic worms, called microfilariae, into the blood.
People with the worms in their blood can give the infection
to others through mosquitoes.

14. DISEASES AND SYMPTOMS
• Although the parasite damages the lymph
system, most infected people have no
symptoms and will never develop clinical
symptoms. These people do not know they
have lymphatic filariasis unless tested.

15. DISEASES AND SYMPTOMS
• • A small percentage of persons
will develop lymphedema. This
is caused by fluid collection
because of improper
functioning of the lymph
system resulting in swelling.
This mostly affects the legs, but
can also occur in the arms,
breasts, and genitalia. Most
people develop these symptoms
years after being infected.

16. DISEASES AND SYMPTOMS
Elephantiasis
The swelling and the decreased
function of the lymph system
make it difficult for the body to
fight germs and infections.
These people will have more
bacterial infections in the skin
and lymph system. This causes
hardening and thickening of the
skin, which is called
elephantiasis. Many of these
bacterial infections can be
prevented with appropriate skin
hygiene and exercise.

17. DISEASES AND SYMPTOMS

18. DISEASES AND SYMPTOMS
Hydrocele/ Scrotal
Swelling

19. DISEASES AND SYMPTOMS
Kidney Damage
This will lead to blood and protein loss in
urine (hematuria).

20. DISEASES AND SYMPTOMS
Tropical Pulmonary Eosinophilia Syndrome
This syndrome is typically found in persons living
with the disease in Asia. Symptoms of tropical
pulmonary eosinophilia syndrome include cough,
shortness of breath, and wheezing. The
eosinophilia is often accompanied by high levels
of IgE (Immunoglobulin E) and antifilarial
antibodies.

21. DIAGNOSIS
1. Night Blood Sampling
1.1. Collect blood specimen from 8 pm to 4 am –
Thick Smear (Giemsa or H&E)
1.2. Microscopic examination for microfilariae
1.3. Concentration Technique (increased
sensitivity)
2. Antigen-detection (ELISA) to detect CFA
(circulating filarial antigen)
“Gold Standard”

22. DIAGNOSIS
3. Search for microfilaria in chylous urine, lymph exudates
and hydrocoele fluid.
4. Search for adult worm
4.1. Lymph node biopsy
4.2. X-Ray (calcified worm)
4.3. Ultrasonography (dancing worm/filarial dance sign)
5. Xenodiagnosis
-mosquito stomach blood, not very helpful

23. TREATMENT
• Antifilarial Drugs
a. Diethylcarbamazine (DEC)
Dosage: 6 mg/kg/day for 12
days
b. Ivermectin
Dosage: single oral dose of
150 ug/kg body weight
c. Combination of 2 =better results

24. TREATMENT
General Measures:
1. Rest
2. Antibiotics
3. Antifungal
4. Physiotherapy
5. Bandaging
Elephantiasis
Elephantoid tissues can be corrected surgically.

25. PREVENTION AND CONTROL
Avoiding mosquito bites is the best form of prevention. The
mosquitoes that carry the microscopic worms usually bite
between the hours of dusk and dawn. If you live in or
travel to an area with lymphatic filariasis:
1. Sleep under a mosquito net.
2. Wear long sleeves and trousers.
3. Use mosquito repellent on exposed skin between dusk
and dawn.

26. PREVENTION AND CONTROL
Even after the adult worms die, lymphedema can develop.
You can ask your physician for a referral to see a
lymphedema therapist for specialized care. Prevent the
lymphedema from getting worse by following several
basic principles:
1. Carefully wash the swollen area with soap and water every
day.
2. Elevate and exercise the swollen arm or leg to move the
fluid and improve the lymph flow.
3. Disinfect any wounds. Use antibacterial or antifungal
cream if necessary.

27. LINKS TO SOURCES
• http://bioweb.uwlax.edu/bio203/s2008/krout_bria/• http://www.cdc.gov/parasites/lymphaticfilariasis/• https://uqu.edu.sa/files2/tiny_mce/plugins/filemanager/

28. THE END