Dracunculiasis (Guinea Worm Disease): A Report Shelly Beard, Nicole Corder, and Majken Kiyohara.
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Transcript of Dracunculiasis (Guinea Worm Disease): A Report Shelly Beard, Nicole Corder, and Majken Kiyohara.
DracunculiasisDracunculiasis(Guinea Worm Disease):(Guinea Worm Disease):
A ReportA Report
Shelly Beard, Nicole Corder, and Majken Kiyohara
Dracunculiasis – In Brief: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:The Report:
Historical highlights The lifecycle Morphology Symptoms Diagnosis Treatment Prevention Socioeconomic impact, past and present The eradication initiative
Old Testament:
021:006 And the LORD sent fiery serpents among the people, and theybit 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; prayunto 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, andset it upon a pole: and it shall come to pass, that every one thatis bitten, when he looketh upon it, shall live.
Historical HighlightsHistorical Highlights
Historical Highlights: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 diseaseto be targeted for worldwide eradication
ClassificationClassification
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 LifecycleThe Lifecycle
The LifecycleThe LifecycleFirst-stage larvae (L1) are released into water by a mature female worm
ŒL1 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
Ž
The LifecycleThe LifecycleInfection 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.
Œ
Ž
The female emergesafter 10-14 months to release larvae in waterand completes the cycle…
Œ
MorphologyMorphology
MorphologyMorphology
Dracunculus medinensis is usually white
The adult female is among the longest of
nematodes:
• Often measures one meter in length
• No more than 1-2 mm wide
(thin like spaghetti or angel hair pasta)
The male is generally much smaller and
rarely recovered from humans, because
he dies shortly after mating
Male
Female
Techniques used to evade the Techniques used to evade the Human Immune System: Human Immune System:
Roundworms have an outer protective cuticle layer; some worms can even survive in pure vinegar
Opiates from Dracunculus medinensis lowerthe 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
SymptomsSymptoms
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:Symptoms:
On occasion worms migrate to joints, die prematurely, and calcify.
The calcified worms can trigger arthritis, locked joints, or permanent crippling and deformities
DiagnosisDiagnosis
Patent DiagnosisPatent Diagnosis
Made by observing visible characteristics of the disease and communicating with the infected person
Prepatent DiagnosisPrepatent 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
TreatmentTreatment
Traditional TreatmentTraditional 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
MedicationsMedications
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 burdenwhen 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 TreatmentInvasive 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
PreventionPrevention
PreventionPrevention
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 waterused for drinking
• Education, education, education !
ChallengesChallenges
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 peoplewith drinking water
Socioeconomic ImpactSocioeconomic Impact
Socioeconomic ImpactSocioeconomic 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 ImpactHistorical 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 ImpactCurrent Impact
Dracunculiasis is currently limited to remote, rural villages in 13 sub-Saharan African countries without access to safe drinking water
The vast majorityof current casesinflict citizens ofthe war-torn nationof Sudan
Distribution by Country of 10,674 Cases of Distribution by Country of 10,674 Cases of Dracunculiasis, 2005 – Dracunculiasis, 2005 – Includes imported casesIncludes 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.
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?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 The Eradication InitiativeInitiative
The Eradication InitiativeThe 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 EradicationPakistan: 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
Thank YouThank You
Shelly Beard
Nicole Corder
Majken Kiyohara