Dracunculiasis, also known as Guinea worm disease (GWD), is a crippling disease caused by the parasite Dracunculus medinensis.
As only 25 human cases were reported in 2016, it is on the verge of eradication.
Please find more information on this disease in the text below or watch expert interview:
What is the disease?
How dangerous is Dracunculiasis?
The death rate of Dracunculiasis is low but great pain and disability are a common outcome.
Additionally Dracunculiasis is a financial and social burden for affected communities.
Who is at risk?
Anyone who drinks stagnant water contaminated by persons with Dracunculiasis is at risk for infection.
People who live in villages with widespread Dracunculiasis are at greatest risk.
How many people are affected by Dracunculiasis?
During the mid-1980s an estimated 3.5 million cases of dracunculiasis occurred in 20 countries worldwide, 17 countries of which were in Africa.
The number of reported cases fell to under 10 000 in 2007, dropping further to 542 cases in 2012, 148 cases in 2013, 126 in 2014, and 22 in 2015.
In 2016, 25 cases were reported globally.
In 2017, 30 cases were reported — 15 in Chad and 15 in Ethiopia; 13 of which were fully contained. For the first time ever, South Sudan reported no human infections for a whole calendar year. No human cases were reported in Mali for the second year in a row. In addition to their human cases, Chad reported 817 infected dogs and 13 infected domestic cats, and Ethiopia reported 11 infected dogs and 4 infected baboons. Despite no human infections, Mali reported 9 infected dogs and 1 infected cat.
More information on infections in dogs:
Since 2012 Guinea worm infections in dogs in Chad were confirmed with annually increasing numbers:
- 21 infections in 2012
- 54 infections in 2013
- 113 infections in 2014
- 483 infections in 2015
- 271 infections in 2017
- 201 infected in Jan-March 2018 (increase of 44%, 140 dogs 2016)
Guinea worm infections in both humans and dogs tend to cluster around the Chari River. The worms infecting dogs are genetically indistinguishable from the worms infecting humans in Chad.
Other countries have reported dogs infected with Guinea worms as well. However, the current pattern and volume of Dracunculiasis transmission in dogs in Chad has never been documented before in other countries or within Chad prior to 2012.
Because Chad has a large domestic and commercial fishing industry along the Chari River and because of the clustering of human cases and dog infections along the Chari River, villagers are being educated to cook their fish well, to bury fish entrails left over from fish processing, and to not allow their dogs to eat fish entrails.
A reward is being offered to report dogs with suspected Dracunculiasis infections and dog owners are encouraged to tether infected dogs until the worms emerge to prevent the dogs from entering and contaminating water.
How do people get Dracunculiasis?
People become infected with Dracunculus medinensis by drinking stagnant water containing copepods which are microscopic crustaceans that carry the infective Guinea worm larvae.
Following drinking contaminated water, these larvae are released from the copepods in the stomach and penetrate the digestive track, passing
into the body cavity. During the next 10 to14 months, the female larvae grow into full-size adults which are 60 to100 centimeters or two to three feet long and as wide as a cooked spaghetti noodle.
What are the signs and symptoms of Dracunculiasis?
People with Dracunculiasis have no symptoms for about one year. Then, the person begins to feel ill with symptoms like:
- slight fever
- itchy rash
A blister then develops which forms on the lower body parts in 80 to 90 percent of cases. While the blister gets bigger over several days it causes a burning pain. When the person puts the affected body part in cool water to ease the symptoms, it is thought that the worm de-tects the temperature change and bursts from the blister to release hundreds of thousands of larvae into the water.
How is the disease developing?
From the time infection occurs, it takes between 10 to 14 months for the transmission cycle to complete until a mature worm emerges from the body.
In addition to the pain of the blister, removing the worm is also very painful. Without proper care the wound often becomes infected by bacteria.
These wound infections can result in one or more of the following complications:
- redness and swelling of the skin (cellulitis)
- boils (abscesses)
- generalized infection (sepsis)
- joint infections (septic arthritis) that can cause the joints to lock and deform (contractures)
- Tetanus as many others as secondary infections with esp. bacteria causing additional symptoms and increasing the severity of the disease even to death.
If the worm breaks during removal it can cause intense inflammation as the remaining part of the dead worm starts to degrade inside the body. This causes more pain, swelling, and cellulitis.
How is Dracunculiasis diagnosed?
Dracunculiasis is diagnosed by seeing the worms emerging from the lesions on the legs of infected individuals and by microscopic examinations of the larvae.
How is Dracunculiasis treated?
There is no drug to treat Dracunculiasis and no vaccine to prevent infection.
Management of Dracunculiasis involves the following steps:
- Each day the affected body part is immersed in a container of water to encourage more of the worm to come out. To prevent contamination, the infected person is not allowed to enter drinking water sources.
- The wound is cleaned.
- Gentle traction is applied to the worm to slowly pull it out. Pulling stops when resistance is met to avoid breaking the worm. Because the worm can be as long as one meter in length, full extraction can take several days to weeks.
- The worm is then wrapped around a rolled piece of gauze or a stick to maintain some tension on the worm and encourage more of the worm to emerge. This also prevents the worm from slipping back inside.
- Afterwards, topical antibiotics are applied to the wound to prevent secondary bacterial infections.
- The affected body part is then bandaged with fresh gauze to protect the site. Medicines are given to help ease the pain of this process and reduce inflammation.
- These steps are repeated every day until the whole worm is successfully pulled out.
The worm can also be surgically removed by a trained doctor in a medical facility before a blister forms.
How can I prevent infection?
Don’t drink unsafe water from open water sources and teach other people to refrain too.
To prevent the spread of the disease:
- drink only water from protected sources or after treatment, e.g. filtering or heating
- prevent people with swellings and wounds from entering water used for drinking
- filter drinking water from unsafe sources to remove the tiny crustaceans that carry the Guinea worm larvae
- provide communities with safe sources of drinking water
How are people educated about Dracunculiasis?
People are educated during household visits by GWEP (Guinea Worm Eradication Program) volunteers and staff and through organized events, such as Worm Weeks.
How is Dracunculiasis transmitted?
People become infected with Dracunculus medinensis by drinking stagnant water containing copepods which are microscopic crustaceans that carry Guinea worm larvae because the larvae are their food.
Once drunk, these larvae are released from the copepods in the stomach and penetrate the digestive track, passing
into the body cavity. During the next 10 to 14 months, the female larvae grow into full-size adults which are 60 to 100 centimeters or two to three feet long and as wide as a cooked spaghetti noodle.
Guinea Worm transmission has a seasonal pattern.
In dry regions, people generally get infected during the rainy season, when stagnant surface water is available.
In wet regions, people generally get infected during the dry season, when surface water is drying up and becoming stagnant.
How can the vector be controlled?
The vector for Dracunculiasis is the copepod. To control this vector, the Guinea Worm Eradication Program (GWEP) puts a measured amount of approved chemical larvicide into the water sources that are suspected to be contaminated. This chemical kills the copepods.
What are the difficulties and challenges in combating Dracunculiasis?
- Finding and containing the last remaining cases are the most difficult and expensive stages of the eradication process as these usually occur in remote, often inaccessible areas.
- Political instability and armed conflict, with the resulting lack of access to disease-endemic areas, are a major constraint, especially in countries where cases are still occurring.
- Dog infections with Dracunculus medinensis pose a challenge to the program particularly in Chad and Ethiopia.
- Infection in other wild animals (e.g. as recently discovered infection in baboons function as a reservoir
The phenomenon was noted in Chad in 2012, and since then several dogs with emerging worms, genetically undistinguishable to those emerging in humans, are being detected in the same at-risk area.
In 2016, more than 1000 dogs in Chad, 14 dogs in Ethiopia, 11 dogs in Mali were reported with Guinea-worm emergence.
What programs exist against Dracunculiasis?
The global campaign to eradicate Guinea worm began in 1980 at the US Centers for Disease Control and Prevention (CDC).
Dracunculiasis or Guinea worm disease eradication was targeted as an ideal indicator of success for the United Nations 1981-1990 International Drinking Water Supply and Sanitation Decade (IDWSSD) because the disease could only be transmitted through contaminated drinking water.
A year later, GWD eradication was adopted as a sub-goal of the IDWSSD. In 1984, CDC was designated as the WHO Collaborating Center for Research, Training, and Eradication of Dracunculiasis.
In 1986 the World Health Assembly (WHA) adopted a formal resolution calling for the eradication of Dracunculiasis. Eradication was defined as the absence of Dracunculiasis and therefore the interruption of transmission for three or more years.
The Carter Center, working closely with Ministries of Health, took the lead for the global Guinea Worm Eradication Program (GWEP) and built local, national and international partnerships. Support came from numerous donor agencies, foundations, institutions and governments.
WHA targeted Dracunculiasis for eradication because it met specific criteria:
- it is biologically and technically possible to eradicate the disease
- there is no chance for the disease to return after the last human case occurs – although the fact that dogs, and recently other wildlife animals have been infected with the same pathogen since 2012 raises new questions
- Dracunculiasis is easily diagnosed because of its signs and symptoms, few diseases can be confused with Dracunculiasis and the public in affected communities know and recognizes the worm
- in each affected country the worms emerge from the skin during certain predicable times of the year
- Dracunculiasis was previously eliminated from parts of the former Soviet Union during the 1920s and from endemic areas of Iran in the 1970s
The benefits of eradication outweighed the costs. The World Bank assessed the socio-economic impact of Dracunculiasis in 1997. It concluded that the costs for Dracunculiasis eradication and morbidity reduction would be significantly less than the continued costs of the disease.
Other direct benefits of eradication would include:
- the development of a group of trained health workers who could provide both Dracunculiasis management and other basic health services
- improvements in water supplies
- water no longer contaminated with Guinea worm
- enhanced advocacy for new safe water sources
- the global community would indirectly benefit from the enhanced culture of disease prevention and social equity afforded by this disease eradication program.
- countries and organizations supporting Dracunculiasis eradication would be helping to reduce the suffering of some of the world’s most underprivileged people.
More in-depth Information
➞ link to for instance
Fitzpatrick C, Sankara DP, Agua JF, Jonnalagedda L, Rumi F, Weiss A, et al. (2017) The cost-effectiveness of an eradication programme in the end game: Evidence from guinea worm disease. PLoS Negl Trop Dis 11(10): e0005922. https://doi.org/10.1371/journal.pntd.0005922
What does Bayer contribute to the fight against Dracunculiasis?
Bayer´s Animal Health business unit is currently working closely with the Vartzer Foundation to evaluate compounds registered for parasite treatment and prevention in animals, esp. dogs, whether these would have an efficacy in infected dogs too.
What is the societal burden of Dracunculiasis?
Dracunculiasis only occurs in the poorest 10 percent of world’s population who have no access to safe drinking water. Therefore, GWD is both a disease of poverty and a cause of poverty.
The disability that occurs during worm removal and recovery
prevents people from working, going to school, and caring for their families.
Disability lasts 8.5 weeks on average but sometimes can be permanent.
When Dracunculiasis was more common, the negative impacts on farming and livestock tending caused financial losses in the millions of dollars each year.
In some villages where infection rates were high, more than 60 percent of children missed school.
Some children were disabled by infection.
Other children needed to work in place of disabled family members.
How did the history of the disease proceed?
Dracunculiasis has been a recognized disease for thousands of years:
- Guinea worm has been found in calcified Egyptian mummies.
- in the 2nd century BC, the Greek writer Agatharchides described this affliction as being endemic amongst certain nomads in what is now Sudan and along the Red Sea
- in the 18th century, Swedish naturalist Carl Linnaeus identified D. medinensis in merchants who traded along the Gulf of Guinea
- during the 1860s the Russian scientist Alexei Pavlovich Fedchenko while living in Samarkand examined worms and noted the presence of water fleas with embryos of the guinea worm within them
- in modern times, the first to describe dracunculiasis and its pathogenesis was the Bulgarian physician Hristo Stambolski, during his exile in Yemen (1877–1878) where he correctly inferred that the cause was infected water which people were drinking
Find more information on the fight against the disease beginning in the 1980s in the „Initiatives and partners“ section