Dracunculiasis, also called Guinea-worm disease, is a
parasitic infection
A parasitic disease, also known as parasitosis, is an infectious disease caused by parasites. Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases is known as parasitolo ...
by the Guinea worm, ''
Dracunculus medinensis
''Dracunculus medinensis'', or Guinea worm, is a nematode that causes dracunculiasis, also known as guinea worm disease. The disease is caused by the female which, at up to in length, is among the longest nematodes infecting humans. In contr ...
''. A person becomes infected by drinking water containing
water fleas
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms).
Over 1000 species have been recognised so far, with many more ...
infected with guinea worm
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e. The worms penetrate the
digestive tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans a ...
and escape into the body. Around a year later, the adult worm migrates to an exit site – usually a lower limb – and induces an intensely painful
blister
A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, usually caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled wi ...
on the skin. The blister eventually bursts to form an intensely painful open wound, from which the worm slowly crawls over several weeks. The wound remains painful throughout the worm's emergence, disabling the infected person for the three to ten weeks it takes the worm to emerge. During this time, the open wound can become infected with
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
, leading to death in around 1% of cases.
There is no medication to treat dracunculiasis. Instead, the mainstay of treatment is the careful wrapping of the emerging worm around a small stick to encourage its exit. Each day, a few more centimeters of the worm emerge, and the stick is turned to maintain gentle tension. With too much tension, the worm can break and die in the wound, causing severe pain and swelling at the
ulcer
An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...
site. Dracunculiasis is a disease of extreme poverty, occurring in places with poor access to clean drinking water. Prevention efforts center on filtering drinking water to remove water fleas, as well as public education campaigns to discourage people from soaking their emerging worms in sources of drinking water.
Humans have had dracunculiasis since at least 1,000 BCE, and accounts consistent with dracunculiasis appear in surviving documents from physicians of antiquity. In the 19th and early 20th centuries, dracunculiasis was widespread across much of Africa and South Asia, affecting as many as 48 million people per year. The effort to eradicate dracunculiasis began in the 1980s following the successful
eradication of smallpox. By 1995, every country with
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
dracunculiasis had established a national eradication program. In the ensuing years, dracunculiasis cases have dropped precipitously, and 15 previously endemic countries have been certified to have eradicated dracunculiasis, leaving the disease endemic in just four countries: Chad, Ethiopia, Mali, and South Sudan. A record low 15 cases of dracunculiasis were reported worldwide in 2021.
[ If the eradication program succeeds, dracunculiasis will become the second human disease ever eradicated.
]
Signs and symptoms
The first signs of dracunculiasis occur around a year after infection, as the full-grown female worm prepares to leave the infected person's body.[ As the worm migrates to its exit site – typically the lower leg, though they can emerge anywhere on the body – some people have ]allergic reaction
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
s, including hives
Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...
, fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
, dizziness
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Dizziness is a common medical c ...
, nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
, vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose.
Vomiting can be the result of ailments like Food-poisoning, foo ...
, and diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
. Upon reaching its destination, the worm forms a fluid-filled blister
A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, usually caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled wi ...
under the skin. Over 1–3 days, the blister grows larger, begins to cause severe burning pain, and eventually bursts leaving a small open wound.[ The wound remains intensely painful as the worm slowly emerges over several weeks to months.
In an attempt to alleviate the excruciating burning pain, the host will nearly always attempt to submerge the affected body part in water. When this occurs and the worm is exposed to water, it spews a white substance into the water containing thousands of larvae. As the worm emerges, the open blister often becomes infected with bacteria, resulting in redness and swelling, the formation of ]abscess
An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...
es, or in severe cases gangrene
Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the ga ...
, sepsis
Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
or lockjaw. When the secondary infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
is near a joint (typically the ankle), the damage to the joint can result in stiffness
Stiffness is the extent to which an object resists deformation in response to an applied force.
The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.
Calculations
The stiffness, k, of a b ...
, arthritis
Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...
, or contracture
In pathology, a contracture is a permanent shortening of a muscle or joint. It is usually in response to prolonged hypertonic spasticity in a concentrated muscle area, such as is seen in the tightest muscles of people with conditions like spasti ...
s.
Infected people commonly harbor multiple worms – with an average 1.8 worms per person; up to 40 at a time – which will emerge from separate blisters at the same time. 90% of worms emerge from the legs or feet. However, worms can emerge from anywhere on the body.
Cause
Dracunculiasis is caused by infection with the roundworm
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
''Dracunculus medinensis
''Dracunculus medinensis'', or Guinea worm, is a nematode that causes dracunculiasis, also known as guinea worm disease. The disease is caused by the female which, at up to in length, is among the longest nematodes infecting humans. In contr ...
''. ''D. medinensis'' larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e reside within small aquatic crustaceans called copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s or water fleas. When humans drink the water, they can unintentionally ingest infected copepods. During digestion the copepods die, releasing the ''D. medinensis'' larvae. The larvae exit the digestive tract by penetrating the stomach and intestine, taking refuge in the abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
or retroperitoneal space
The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on their ...
. Over the next two to three months the larvae develop into adult male and female worms. The male remains small at long and wide; the female is comparatively large, often over long and wide. Once the worms reach their adult size they mate, and the male dies. Over the ensuing months, the female migrates to connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
or along bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
s, and continues to develop.
About a year after the initial infection, the female migrates to the skin, forms an ulcer
An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...
, and emerges. When the wound touches freshwater, the female spews a milky-white substance containing hundreds of thousands of larvae into the water. Over the next several days as the female emerges from the wound, she can continue to discharge larvae into surrounding water. The larvae are eaten by copepods, and after two to three weeks of development, they are infectious to humans again.
Diagnosis
Dracunculiasis is diagnosed by visual examination – the thin white worm emerging from the blister is unique to this disease. Dead worms sometimes calcify and can be seen in the subcutaneous tissue
The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macr ...
by X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
.[
]
Treatment
There is no medicine to kill ''D. medinensis'' or prevent it from causing disease once within the body. Instead, treatment focuses on slowly and carefully removing the worm from the wound over days to weeks. Once the blister bursts and the worm begins to emerge, the wound is soaked in a bucket of water, allowing the worm to empty itself of larvae away from a source of drinking water.[ As the first part of the worm emerges, it is typically wrapped around a piece of gauze or a stick to maintain steady tension on the worm, encouraging its exit.][ Each day, several centimeters of the worm emerge from the blister, and the stick is wound to maintain tension. This is repeated daily until the full worm emerges, typically within a month. If too much pressure is applied at any point, the worm can break and die, leading to severe swelling and pain at the site of the ulcer.
Treatment for dracunculiasis also tends to include regular wound care to avoid infection of the open ulcer while the worm is leaving. The U.S. ]Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
(CDC) recommends cleaning the wound before the worm emerges. Once the worm begins to exit the body, the CDC recommends daily wound care: cleaning the wound, applying antibiotic ointment, and replacing the bandage with fresh gauze.[ ]Painkiller
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It i ...
s like aspirin
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
or ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arte ...
can help ease the pain of the worm's exit.[
]
Outcomes
Dracunculiasis is a debilitating disease, causing substantial disability in around half of those infected. People with worms emerging can be disabled for the three to ten weeks it takes the worms to fully emerge. When worms emerge near joints, the inflammation around a dead worm, or infection of the open wound can result in permanent stiffness, pain, or destruction of the joint. Some people with dracunculiasis have continuing pain for 12 to 18 months after the worm has emerged. Around 1% of dracunculiasis cases result in death from secondary infections of the wound.
When dracunculiasis was widespread, it would often affect entire villages at once. Outbreaks occurring during planting and harvesting seasons severely impair a community's agricultural operations – earning dracunculiasis the moniker "empty granary disease" in some places. Communities affected by dracunculiasis also see reduced school attendance as children of affected parents must take over farm or household duties, and affected children may be physically prevented from walking to school for weeks.
Infection does not create immunity, so people can repeatedly experience dracunculiasis throughout their lives.
Prevention
There is no vaccine for dracunculiasis, and once infected with ''D. medinensis'' there is no way to prevent the disease from running its full course.[ Consequently, nearly all effort to reduce the burden of dracunculiasis focuses on preventing the transmission of ''D. medinensis'' from person to person. This is primarily accomplished by filtering drinking water to physically remove copepods. Nylon filters, finely woven cloth, or specialized filter straws are all effective means of copepod removal. Sources of drinking water can be treated with the ]larvicide
A larvicide (alternatively larvacide) is an insecticide that is specifically targeted against the larval life stage of an insect. Their most common use is against mosquitoes. Larvicides may be contact poisons, stomach poisons, growth regulators, o ...
temephos
Temefos or temephos (trade name Abate) is an organophosphate larvicide used to treat water infested with disease-carrying insects including mosquitoes, midges, and black fly larvae.
As with other organophosphates, temephos affects the central ne ...
, which kills copepods. Where possible, open sources of drinking water are replaced by deep wells that can serve as new sources of clean water. Public education campaigns inform people in affected areas how dracunculiasis spreads and encourage those with the disease to avoid soaking their wounds in bodies of water that are used for drinking.
Epidemiology
Dracunculiasis is nearly eradicated, with just 15 cases reported worldwide in 2021. This is down from 27 cases in 2020, and dramatically less than the estimated 3.5 million annual cases in 20 countries in 1986 – the year the World Health Assembly
The World Health Assembly (WHA) is the forum through which the World Health Organization (WHO) is governed by its 194 member states. It is the world's highest health policy setting body and is composed of health ministers from member states.
T ...
called for dracunculiasis' eradication. Dracunculiasis remains endemic in just four countries: Chad, Ethiopia, Mali, and South Sudan.[
Dracunculiasis is a disease of extreme poverty, occurring in places where there is poor access to clean drinking water. Cases tend to be split roughly equally between males and females, and can occur in all age groups. Within a given place, dracunculiasis risk is linked to occupation; people who farm or fetch drinking water are most likely to be infected.
Cases of dracunculiasis have a seasonal cycle, though the timing varies by location. Along the Sahara desert's southern edge, cases peak during the mid-year rainy season (May–October) when stagnant water sources are more abundant. Along the ]Gulf of Guinea
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. The intersection of the Equator and Prime Meridian (zero degrees latitude and longitude) is in the ...
, cases are more common during the dry season (October–March) when flowing water sources dry up.
History
Dracunculiasis has been with humans for at least 3,000 years, as the remnants of a guinea worm infection have been found in the mummy
A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay fu ...
of a girl entombed in Egypt around 1,000 BCE
Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the or ...
. Diseases consistent with the effects of dracunculiasis are referenced by writers throughout antiquity. The disease of "fiery serpents" that plagues the Hebrews in the Old Testament
The Old Testament (often abbreviated OT) is the first division of the Christian biblical canon, which is based primarily upon the 24 books of the Hebrew Bible or Tanakh, a collection of ancient religious Hebrew writings by the Israelites. The ...
(around 1250 BCE
Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the or ...
) is often attributed to dracunculiasis. Plutarch
Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo in Delphi. He is known primarily for his ''P ...
's ''Symposiacon'' refers to a (now lost) description of a similar disease by the 2nd century BCE writer Agatharchides
Agatharchides or Agatharchus ( grc-gre, Ἀγαθαρχίδης or , ''Agatharchos'') of Cnidus was a Greek historian and geographer (flourished 2nd century BC).
Life
Agatharchides is believed to have been born at Cnidus, hence his appellation. A ...
concerning a "hitherto unheard of disease" in which "small worms issue from eople'sarms and legs... insinuating themselves between the muscles ogive rise to horrible sufferings". Many of antiquity's famous physicians also write of diseases consistent with dracunculiasis, including Galen
Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one of ...
, Rhazes
Abū Bakr al-Rāzī (full name: ar, أبو بکر محمد بن زکریاء الرازي, translit=Abū Bakr Muḥammad ibn Zakariyyāʾ al-Rāzī, label=none), () rather than ar, زکریاء, label=none (), as for example in , or in . In m ...
, and Avicenna
Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic G ...
; though there was some disagreement as to the nature of the disease, with some attributing it to a worm, while others considered it to be a corrupted part of the body emerging. In his 1674 treatise on dracunculiasis, Georg Hieronymous Velschius first proposed that the Rod of Asclepius
In Greek mythology, the Rod of Asclepius (⚕; grc, Ράβδος του Ασκληπιού, , sometimes also spelled Asklepios), also known as the Staff of Aesculapius and as the asklepian, is a serpent-entwined rod wielded by the Greek god A ...
, a common symbol of the medical profession, depicts a recently extracted guinea worm.
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
included the guinea worm in his 1758 edition of ''Systema Naturae
' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...
'', naming it ''Gordius medinensis''. In Johann Friedrich Gmelin
, fields =
, workplaces = University of GöttingenUniversity of Tübingen
, alma_mater = University of Tübingen
, doctoral_advisor = Philipp Friedrich GmelinFerdinand Christoph Oetinger
, academic_advisors =
, doctora ...
's 13th edition of ''Systema Naturae'' (1788), he renamed the worm ''Filaria medinensis'', leaving ''Gordius'' for free-living worms. Henry Bastian authored the first detailed description of the worm itself, published in 1863. The following year, in his book ''Entozoa'', Thomas Spencer Cobbold
Thomas Spencer Cobbold FRS (26 May 182810 March 1886) was an English biologist.
Life
He was born at Ipswich, the third son of Rev. Richard Cobbold, author of the ''History of Margaret Catchpole''.
After graduating in medicine at the Univers ...
used the name ''Dracunculus medinensis'', which was enshrined as the official name by the International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries.
Orga ...
in 1915. Despite longstanding knowledge that the worm was associated with water, the lifecycle of ''D. medinensis'' was the topic of protracted debate. Alexei Pavlovich Fedchenko
Alexei Pavlovich Fedchenko (russian: Алексей Павлович Федченко;
31 August/15 September 1873), a.k.a. Alexei Pavlovich Fedtschenko, was a Russian naturalist and explorer well known for his travels in central Asia. Alternat ...
filled a major gap with his 1870 publication describing that ''D. medinensis'' larvae can infect and develop inside ''Cyclops'' crustaceans. The next step was shown by Robert Thomson Leiper
Robert Thomson Leiper (17 April 1881 – 21 May 1969) FRS CMG was a British parasitologist and helminthologist.
Early life and education
Leiper was born on 17 April 1881 in Witch Road, Kilmarnock, Scotland; the eldest of three children of John ...
, who described in a 1907 paper that monkeys fed ''D. medinensis''-infected ''Cyclops'' developed mature guinea worms, while monkeys directly fed ''D. medinensis'' larvae did not.
In the 19th and 20th centuries, dracunculiasis was widespread across nearly all of Africa and South Asia, though we lack exact case counts from the pre-eradication era. In a 1947 article in the ''Journal of Parasitology
The ''Journal of Parasitology'' is a peer-reviewed medical journal covering research on parasites published bimonthly by Allen Press on behalf of the American Society of Parasitologists. Content includes research articles, brief research notes, ...
'', Norman R. Stoll used rough estimates of populations in endemic areas to suggest that there could be as many as 48 million cases of dracunculiasis per year. In 1976, the WHO estimated the global burden at 10 million cases per year. Ten years later, as the eradication effort was beginning, the WHO estimated 3.5 million cases per year worldwide.
Etymology
Dracunculiasis' Latin name, ''Dracunculus medinensis'' ("little dragon from Medina"), derives from its one-time high incidence in the city of Medina
Medina,, ', "the radiant city"; or , ', (), "the city" officially Al Madinah Al Munawwarah (, , Turkish: Medine-i Münevvere) and also commonly simplified as Madīnah or Madinah (, ), is the Holiest sites in Islam, second-holiest city in Islam, ...
(in modern Saudi Arabia
Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in Western Asia. It covers the bulk of the Arabian Peninsula, and has a land area of about , making it the fifth-largest country in Asia, the second-largest in the A ...
), and its common name, Guinea worm, is due to a similar past high incidence along the Guinea coast of West Africa
West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Maurit ...
. It is no longer endemic in either location.
Eradication
The campaign to eradicate dracunculiasis began at the urging of the CDC in 1980. Following smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
eradication (last case in 1977; eradication certified in 1981), dracunculiasis was considered an achievable eradication target since it was relatively uncommon and preventable with only behavioral changes. In 1981, the steering committee for the United Nations International Drinking Water Supply and Sanitation Decade (a program to improve global drinking water during the decade from 1981 to 1990) adopted the goal of eradicating dracunculiasis as part of their efforts. The following June, an international meeting termed "Workshop on Opportunities for Control of Dracunculiasis" concluded that dracunculiasis could be eradicated through public education, drinking water improvement, and larvicide treatments. In response, India began its national eradication program in 1983. In 1986, the 39th World Health Assembly issued a statement endorsing dracunculiasis eradication and calling on member states to craft eradication plans. The same year, The Carter Center began collaborating with the government of Pakistan to initiate its national program, which then launched in 1988. By 1996, national eradication programs had been launched in every country with endemic dracunculiasis: Ghana and Nigeria in 1989; Cameroon in 1991; Togo, Burkina Faso, Senegal, and Uganda in 1992; Benin, Mauritania, Niger, Mali, and Côte d'Ivoire in 1993; Sudan, Kenya, Chad, and Ethiopia in 1994; Yemen and the Central African Republic in 1995.
Each national eradication program had three phases. The first phase consisted of a nationwide search to identify the extent of dracunculiasis transmission and develop national and regional plans of action. The second phase involved the training and distribution of staff and volunteers to provide public education village-by-village, surveil for cases, and deliver water filters. This continued and evolved as needed until the national burden of disease was very low. Then in a third phase, programs intensified surveillance efforts with the goal of identifying each case within 24 hours of the worm emerging and preventing the person from contaminating drinking water supplies. Most national programs offered voluntary in-patient centers, where those affected could stay and receive food and care until their worms were removed.
In May 1991, the 44th World Health Assembly called for an international certification system to verify dracunculiasis eradication country-by-country. To this end, in 1995 the WHO established the International Commission for the Certification of Dracunculiasis Eradication (ICCDE). Once a country reports zero cases of dracunculiasis for a calendar year, the ICCDE considers that country to have interrupted guinea worm transmission, and is then in the "precertification phase". If the country repeats this feat with zero cases in each of the next three calendar years, the ICCDE sends a team to the country to assess the country's disease surveillance systems and to verify the country's reports.[ The ICCDE can then formally recommend the ]WHO Director-General
The director-general of the World Health Organization (WHO) is the chief executive officer of WHO and the principal advisor to the United Nations on matters pertaining global health. The director general is elected by and answers to the World Heal ...
certify a country as free of dracunculiasis.
Since the initiation of the global eradication program, the ICCDE has certified 15 of the original endemic countries as having eradicated dracunculiasis: Pakistan in 1997; India in 2000; Senegal and Yemen in 2004; the Central African Republic and Cameroon in 2007; Benin, Mauritania, and Uganda in 2009; Burkina Faso and Togo in 2011; Côte d'Ivoire, Niger, and Nigeria in 2013; and Ghana in 2015.
Other animals
In addition to humans, ''D. medinensis'' can infect dogs. Infections of domestic dogs have been particularly common in Chad, where they helped reignite dracunculiasis transmission in 2010. Dogs are thought to be infected by eating a paratenic host
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' ( symbiont). The guest is typically provided with nourishment and shelter. Examples include ...
, likely a fish or amphibian. As with humans, prevention efforts have focused on preventing infection by encouraging people in affected areas to bury fish entrails as well as to identify and tie up dogs with emerging worms so that they cannot access drinking water sources until after the worms have emerged. Domestic ferrets can be infected with ''D. medinensis'' in laboratory settings, and have been used as an animal disease model
An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of ha ...
for human dracunculiasis.
Different ''Dracunculus'' species can infect snakes, turtles, and other mammals. Animal infections are most widespread in snakes, with nine different species of ''Dracunculus'' described in snakes in the United States, Brazil, India, Vietnam, Australia, Papua New Guinea, Benin, Madagascar, and Italy. The only other reptile affected is the snapping turtle
The Chelydridae is a family of turtles that has seven extinct and two extant genera. The extant genera are the snapping turtles, ''Chelydra'' and '' Macrochelys''. Both are endemic to the Western Hemisphere. The extinct genera are '' Acherontem ...
with infected common snapping turtles described in several U.S. states, and a single infected South American snapping turtle described in Costa Rica. Infections of other mammals are limited to the Americas. Raccoon
The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...
s in the U.S. and Canada are most widely impacted, particularly by '' D. insignis''; however, ''Dracunculus'' worms have also been reported in American skunks, coyotes, foxes, opossums, domestic dogs, domestic cats, and (rarely) muskrats and beavers.
Notes
References
Works cited
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
*
Nicholas D. Kristof from the New York Times follows a young Sudanese boy with a Guinea Worm parasite infection who is quarantined for treatment as part of the Carter program
* ttps://www.who.int/health-topics/dracunculiasis World Health Organization on Dracunculiasis
{{Portal bar, Medicine
Infectious diseases with eradication efforts
Helminthiases
Parasitic infestations, stings, and bites of the skin
Rare infectious diseases
Tropical diseases
Waterborne diseases