Transcript Dracunculiasis (Guinea Worm Disease): A Report

Dracunculiasis
(Guinea Worm Disease):
A Report
Shelly Beard, Nicole Corder, and
Majken Kiyohara
Dracunculiasis – In Brief:
 Commonly known as the guinea worm disease
 Caused by the largest of tissue parasites
affecting humans, the parasitic roundworm
Dracunculus medinensis
 Transmitted to people when they drink water
containing copepods that are infected with
Dracunculus medinensis larvae
 Rarely fatal but often incapacitating for several
months
 Not currently possible to prevent or treat with
drugs
The Report:
 Historical highlights
 The lifecycle
 Morphology
 Symptoms
 Diagnosis
 Treatment
 Prevention
 Socioeconomic impact, past and present
 The eradication initiative
Historical Highlights
Old Testament:
021:006 And the LORD sent fiery serpents among the people, and they
bit the people; and much people of Israel died.
021:007 Therefore the people came to Moses, and said, We have sinned,
for we have spoken against the LORD, and against thee; pray
unto the LORD, that he take away the serpents from us.
And Moses prayed for the people.
021:008 And the LORD said unto Moses, Make thee a fiery serpent, and
set it upon a pole: and it shall come to pass, that every one that
is bitten, when he looketh upon it, shall live.
Historical Highlights:
 The 'fiery serpent' mentioned in the Old Testament
 The serpents coiled around the staff of Hermes, the
symbol of a physician
 Believed to be anything from exposed nerves to dead
tissue in the Middle Ages
 It was suggested that they were worms in mid 1700s
 1905: The life cycle was described
 1986: Dracunculiasis was chosen as the next disease
to be targeted for worldwide eradication
Classification
Dracunculus medinensis:
 Nematode (also known as roundworms)
 Superfamily: Dracunculoidea
 Order: Spirurida
• Mammalian tissue parasites
• Eggs or larvae require arthropods (insects
or crustaceans) as intermediate hosts
The Lifecycle
The Lifecycle
First-stage larvae (L1)
are released into
water by a mature
female worm

L1 remain active in the
water up to 1 week
until they are ingested
by a suitable copepod
The transformation to
infectious third stage
larvae (L3) occurs
within 2 weeks


The Lifecycle
Infection of man is
effected when
swallowing infected
copepods
After 3 month the
worms mate and the
male dies. The female
continues to grow and
travel down the muscle
planes.
The female emerges
after 10-14 months to
release larvae in water
and completes the cycle…





Morphology
Morphology
medinensis is usually
 Dracunculus
white
adult female is among the
 The
longest of nematodes:
•
•
Often measures one meter in length
No more than 1-2 mm wide
(thin like spaghetti or angel hair
pasta)
male is generally much smaller
 The
and rarely recovered from humans,
because he dies shortly after
mating
Female
Male
Techniques used to evade the Human
Immune System:
 Roundworms have an outer protective cuticle
layer; some worms can even survive in pure
vinegar
 Opiates from Dracunculus medinensis lower
the sensation of pain in the human host and
significantly decrease the immune systems’
responsiveness
 Antigen cloaking, disguises itself as human
 Manipulate the humans' immune system to
prevent acquisition of immunity
Symptoms
Symptoms:
 Most often asymptomatic from time of
infection until days before emergence
 Pre-partum Immune response:
• Fever, ulceration, and a painful burning
sensation in the area where the worm will
present
 Post-partum susceptibility to secondary
infections in open wounds
Symptoms:
 On occasion worms migrate to joints, die
prematurely, and calcify.
 The calcified worms can trigger arthritis,
locked joints, or permanent crippling and
deformities
Diagnosis
Patent Diagnosis
 Made by observing visible characteristics
of the disease and communicating with the
infected person
Prepatent Diagnosis
 Desirable in an effort to achieve containment of
the disease
 Possible to discover infection up to six months
before emergence
• Falcon Assay Screening Test-Enzyme-Linked
Immunosorbent Assay (FAST-ELISA)
• Enzyme-linked Immunoelectrotransfer Blot (EITB)
technique
 However, testing is complex, expensive and not well
suited for the socioeconomically challenged areas
where Dracunculiasis still occurs
Treatment
Traditional Treatment
 Traditional treatment starts when the worm
begins to emerge from the body
 The worm is wrapped around a small stick in
order to prevent retraction and facilitate the
extraction which can take weeks
 For the ones fortunate enough to afford it:
• An analgesic can be taken to reduce the swelling
associated with the blister
• Antibiotic ointment and proper cleansing can be used to
prevent secondary bacterial infections
Medications
 The medications generally used for parasitic
worm infections do not work to eliminate
Dracunculus medinensis:
• Treatment with drugs such as diethylcarbamazine,
albendazole, and invermectin don’t display a
statistically significant reduction in worm burden
when compared with controls
• Mebendazole usage increased the chance of the worm
emerging in locations other than the feet and legs
 Vaccines are currently not available, and
immunity isn’t acquired (re-infections are
possible)
Invasive Treatment
 Surgical removal of the worm (before a blister
forms) shortens the duration of the debilitating
pain and prevents further contamination of water
sources
 However, this form of treatment is rarely desirable
or even an option in socioeconomically challenged
areas
Prevention
Prevention
 Lack of treatment options and the burden of care
during the long infectious process brings the
focus to prevention
 Preventative measures:
• Treating contaminated water sources with larvicide
• Providing drinking water from underground sources
• Filtering to remove copepods from surface water
used for drinking
• Education, education, education !
Challenges
 Cultural and religious practices
• Chemicals should not be added to sacred ponds
• Fear of “filtering off the power” of sacred water
• Belief that Dracunculiasis is a result of witchcraft
 Getting to all the rural locations with occurrences
 Social unrest, such as ongoing war in Sudan
This pond serves 1,500 people
with drinking water
Socioeconomic Impact
Socioeconomic Impact
 It has been estimated that infected people
lose 100 days of work per year
 Children are absent from school for 25%
of the school year, if they or members of
their family are infected
 The cost in lost revenue for the individual
and the community can be very high
Historical Impact
 Written and pictorial documents indicate
that Dracunculus medinensis has affected
mankind for many centuries
 The titles “Guinea” and “Medina” stem
from areas with significant incidences of
the disease
 A finding of a male worm in a mummy
indicates that the wealthy were also
susceptible to infection
Current Impact
 Dracunculiasis is currently limited to remote,
rural villages in 13 sub-Saharan African
countries without access to safe drinking water
 The vast majority
of current cases
inflict citizens of
the war-torn nation
of Sudan
Distribution by Country of 10,674 Cases of
Dracunculiasis, 2005 – Includes imported cases
 The last known indigenous case occurred
in Kenya in 1994, but this country has
been kept in the stage of pre-certification
of eradication because of annual
importations of cases from Sudan.
Dracunculiasis in the USA?
A case history from 1995:
 Nine year old emigrant from Sudan. Before leaving
Sudan, a Dracunculus medinensis worm was extracted
successfully from her right leg
 After arriving in the United States another worm began to
emerge from her left leg
 She presented to a clinic in Tennessee with a secondary
infection; treatment with antibiotics was unsuccessful
 Surgical intervention facilitated removal of the
fragmented worm, pus, and necrotic tissue
 With proper outpatient therapy, the girl was able to walk
and returned to normal
The Eradication
Initiative
The Eradication Initiative
 In the 1980s a global campaign was launched to
eradicate Dracunculiasis worldwide
• At that time Dracunculiasis was known to inflict India,
Pakistan, 16 sub-Saharan countries in Africa, as well
as Yemen
• Eradication efforts began in 1982 in India and shortly
thereafter in Pakistan, Ghana, Nigeria, and Cameroon
 By 1995, all of the known endemic countries
established eradication programs
 Between 1980 and now, the cases worldwide
have been reduced by more than 99.5%
Pakistan: An Example of Eradication
 Village-wide search for cases of Dracunculiasis in 1987
• Reached 47,401 of the 50,000 suspected endemic villages
 The main interventions: monofilament nylon or polyester
cloth filters, and chemical treatment of drinking water
sources with temephos
 Trained healthcare workers in villages to identify and
report cases of Dracunculiasis
 Case containment began in 1990
 Incentive rewards were offered in 1991 to any health
worker or individual reporting a case of Dracunculiasis in
a village
 Pakistan has been free from Dracunculiasis since 1994
Shelly Beard
Nicole Corder
Thank
You
Majken Kiyohara