Wuchereria bancrofti & Brugia malayi

Ashley Skellie & Karissa Jensen

Background Lymphatic filariasis and

elephantiasis Leading cause of permanent

disability worldwide120 million people affected

More than 30% have severe cases

One billion people are at risk in over 80 countries

BackgroundElephatiasis

Was confused with leprosy Nonsense word

WWII soldiers feared the disease

Wuchereria bancrofti Responsible for 90% of lymphatic filariasis. Likely brought to New World by slave trade Lingered near Charleston, NC until 1920s

Brugia malayi Microfilariae first discovered in 1927 In 1940, adult form discovered

Hosts

Definitive Host:Humans

Intermediate Host:Mosquito

77 species Anopheles, Aedes,

Culex, and Mansonia

Geographical Range

Wuchereria bancrofti

Asia Subtropical and tropical Mostly India

Africa

The Pacific

Americas Brazil Haiti Guyana Dominican Republic

Brugia malayi

Asia

South and South East

South China

Indonesia

Thailand

Vietnam

Malaysia

Philippines

South Korea

Geographical Range

Morphology

Microfilariae

Larvae

Adults

MicrofilariaeConsidered advanced embryosRetain egg membrane sheathWhen stained, can see nuclei and organs

Nuclei are diagnostic

Maximum number in peripheral blood occurs between 10pm and 2am

During the day, found in tissues

Larvae

Stage found in mosquito

Microfilariae ingested and turns into L1 for 8 days

Molts into L2ShortSausage-shapedLack anus

2 to 4 days later, molt to L3 Become elongated, gut development completed

Juveniles 1.4 to 2.0 mm

Adults

Wuchereria bancroftiFemales

6-10 cm Vuvla is near the

level of the middle of their esophagus

Ovoviviparous, producing thousands of microfilariae

Males 40 mm Finger-like tail

No nuclei in end of tail

Brugia malayiFemales

80-100 mm Vuvla is near the level

of the middle of their esophagus

Males 13.5-20.5 mm Tail

Curved ventrally Bears 3 to 4 pairs

of both adanal and postanal papillae.

Spicules are unequal and dissimilar

Left papillae more complex

Nuclei in end of tail

AdultsLong and slender

Smooth cuticle and bluntly rounded ends

Head is slightly swollen and bears two circles of papillae

Mouth is small, buccal capsule is lacking

Live in lymphatic ducts Afferent lymph channels near

major lymph glands of lower body

Take 6 to 12 months to mature

Life Cycle

Symptoms

Lymphatic filariasisAsymptomatic Phase, Inflammatory

Phase, Obstructive Phase

IgE mediated allergic response which brings on asthma-like symptoms

Elephantiasis Swelling in legs, arms, genitalia, breasts Thickening of skin and underlying tissues

Elephantiasis is more common with Wuchereria bancrofti infections

Diagnosis

Blood Sample Nighttime draw to ensure microfilariae in sample Presence of antibodies

Antifilarial IgG4

Finger-prick Detects antigens Taken anytime during the day

Polymerase Chain Reaction (PCR) Molecular level Detects as little as 1 picogram of microfilariae DNA to

determine which species is present

X-ray and ultrasonography

Treatment

Diethylcarbamazine (DEC) Many side effects Kills microfilariae and usually adults with careful administration

Ivermectin Only kills microfilariae Best when combined with DEC or albendazole

Clean infected areas daily Prevents bacterial infections

Exercise or use pressure bandages Allows movement of bodily fluids

No vaccines are available

WolbachiaWolbachia bacteria in symbiosis with Wuchereria

bancrofti

Bacteria lives inside worm

Antibiotics used to kill bacteria, and kill the W. bancrofti at the same time

Control

Mosquito control and preventative measures

Repellant applied to skin and bed nets

Wear pants and long sleeves near reservoirs and vectors, especially at night

Mass treatments to entire communities

Education

Review

What are the definitive and intermediate hosts?

What are the 3 morphological forms?

Name one difference between Wuchereria bancrofti and Brugia malayi.

What is the infective stage in the life cycle?

Is elephantiasis more common in Wuchereria bancrofti or Brugia malayi?

Name two treatments.