Between 2 and 8 April 2020, six suspected human cases of dracunculiasis in Duli village, Gog district, Gambella region, Ethiopia, were reported to WHO. As of 27 April 2020, the Ethiopian Dracunculiasis Eradication Program (EDEP) had detected one additional person with an emerged worm, morphologically consistent with human guinea worm, bringing the total to seven suspected cases. This report comes after more than two consecutive years of zero reporting, as the last cases were reported in December 2017. Since its establishment in 1993, the EDEP has made remarkable progress towards interruption of disease transmission in humans despite the existence of low-level transmission of the parasite in non-human hosts such as dogs and peri-domestic baboons.
Of the seven suspected cases, five were detected from the Angota side of Duli village and two suspected cases from Metaget Dipach and Wadmaro villages in Gog Dipach Kebele. All the infected people used unsafe drinking water from farm ponds. These water sources were reported to be associated with the baboon infection in June 2019 in the same village.
Worm specimens from all the suspected cases have been collected and are ready for shipment to the US Centers for Disease Control laboratory for confirmation1. Morphologically, all specimens are consistent with Dracunculus medinensis.
Figure 1. Guinea worm disease (GWD) case trend by year from 1993 to 2020 YTD*
*The seven cases of 2020 are pending confirmation
Public health response
In response to the outbreak, a team composed of members from the Ethiopian Public Health Institute (EPHI), Gambella Regional Health Bureau (RHB) and The Carter Center (TCC), the main global partner of WHO in support of guinea worm eradication, carried out a preliminary investigation and instituted immediate intervention measures.
These include:As of 11 May 2020, active case search had been conducted in seven villages (the villages where the cases were detected and the nearby at-risk villages). During the investigation, 217 households were visited, and 1,447 people were interviewed and provided with health education in Gog district. Similarly, 2,302 people were interviewed from adjacent villages and three non-village areas of Abobo district. As of 8 May 2020, a total of 173 suspected cases have been identified and admitted to a case containment center (CCC) for close follow up, of which 108 have been discharged and the remaining 65 suspected cases, which include the above-mentioned seven suspect cases, will be discharged if guinea worm disease is ruled out. There were 557 people identified as having used the same water source(s) last year, as the seven current suspected cases. They are being followed up daily in their places of residence by the village-based volunteer, guinea worm officers and health extension workers. Abate larvicide treatment has been applied in all known eligible ponds at Duli farms and in the villages of Metaget Dipach and Wadmaro in Gog Dipach Kebele. This will be repeated every month until the end of the transmission season. Filter utilization practice was assessed during the inspection, and 80 pipes and 60 cloth filters were distributed as replacements. WHO has provided guidance on how to conduct guinea worm disease activities in the field during the COVID-19 pandemic. WHO has maintained a strong surveillance system in all the refugee camps of Gambella and Benishangul Gumuz regions.
WHO risk assessment
Dracunculiasis, one of the Neglected Tropical Diseases (NTDs), is caused by the parasite Dracunculus medinensis (nematode-roundworm).
It is transmitted usually by drinking water containing water fleas-also called copepods (small crustaceans) which are infected with larvae of D. medinensis. Eating uncooked fish or other aquatic animals bearing the guinea worm infected larvae is another plausible route of transmission. Following ingestion, the larvae migrate through the intestinal wall into body tissues, where they develop into adult worms and slowly migrate in the subcutaneous tissues toward the skin surface, causing painful blisters that rupture when it comes in contact with water, allowing the female worm to emerge and release larvae.
The larvae are ingested by the copepods and after two weeks, these larvae metamorphose in the body cavities of the copepods and become infective. From the time infection occurs, it takes between 10–14 months for the transmission cycle to complete until a mature worm emerges from the body.
Symptoms of guinea worm disease can include the following: Dizziness, a mild fever, uncomfortable rash, nausea, vomiting, and diarrhea.
While the death rate is low, disability is a common outcome of guinea worm disease: infected people become non-functional for weeks or months. People have difficulty moving around because of the pain and complications caused by secondary bacterial infections. The disability that occurs during worm removal and recovery prevents people from working in their fields, tending animals, going to school, and caring for their families; hence, creating an economic and social burden for affected communities along with a vicious circle of poverty.
It affects people in rural, deprived and isolated communities who depend mainly on open surface water sources such as ponds for drinking water. Guinea worm disease occurs in the poorest 10% of the world’s population who have no access to safe drinking water or health care. People who live in villages where there has been a case of guinea worm disease in a human or animal in the recent past are at greatest risk.
While Guinea worm transmission is limited to only two districts (Gog and Abobo of Gambella region) in Ethiopia, the presence of hard to reach communities and lack of safe water sources in remote non-village areas, a large refugee influx, and animal infections with an unknown role in transmission of dracunculiasis, remain significant challenges for guinea worm disease elimination in Ethiopia.
In Ethiopia, only the region of Gambella remains endemic for the disease. Current human cases are reported from Gog district in this region. In Gog and Abobo districts of the Gambella region, a low-level transmission of guinea worm among dogs and peri-domestic baboons is being reported. Hence, communities living in the area are at higher risk of contracting the disease.
The potential for the international spread is low. However, as a result of the regular cross-border population movement between Ethiopia and South Sudan, due to insecurity in South Sudan and activities of nomadic pastoralists, the risk of spreading Guinea worm disease between the two countries always remains high.
Within the context of the COVID-19 pandemic, health systems are strained worldwide due to the rapidly increasing demand of services for the management of this disease and other existing ones. Support from The Carter Center and WHO has reinforced active surveillance in all the communities of Gog and Abobo districts including those living in cross-border areas, particularly in and around refugee camps, to prevent any spread of the disease to South Sudan.
There is no vaccine to prevent the disease, nor is there any medication to treat patients. Prevention is possible, as successful implementation of preventive strategies have driven the disease to the verge of eradication. Prevention strategies include:heightening surveillance to detect every case within 24 hours of worm emergence; preventing transmission from each worm by isolating and treating the case, through regular cleaning and bandaging of affected areas of skin until the worm is completely expelled from the body; preventing contamination of drinking-water by preventing infected people or animal hosts with emerging worms from wading into water; ensuring wider access to improved drinking-water supplies to prevent infection; filtering water from open water bodies before drinking; implementing vector control by using the larvicide temephos; and promoting health education and behavioural change.
Currently they are only five countries with indigenous transmission of the disease: Angola, Chad, Ethiopia, Mali2 and South Sudan. Each country has its own national Guinea Worm Eradication Program.
After claiming interruption of transmission, endemic countries must show and document evidence of absence of indigenous transmission of guinea worm disease for at least three consecutive years to be eligible for consideration by the International Commission for the Certification of Dracunculiasis Eradication (ICCDE). The ICCDE decides, after satisfactory deliberation, whether or not to recommend the country for certification by the World Health Organization as free of guinea worm transmission.
For more information on Dracunculiasis (guinea-worm disease):WHO, Dracunculiasis (guinea-worm disease) fact sheet WHO, Dracunculiasis eradication The Carter Center, Guinea Worm Case Totals The Carter Center, Guinea worm outbreak in Ethiopia in 2017 CDC Parasites - Guinea Worm Elimination of Guinea Worm Disease in Ethiopia; Current Status of the Disease’s, Eradication Strategies and Challenges to the End Game WHO guidance document - COVID-19: Operational guidance for maintaining essential health services during an outbreak
1WHO requirement: All worm specimens should be obtained from each case for laboratory confirmation and sent to the WHO Collaborating Center for Research, Training, and Control of Dracunculiasis at the United States Centers for Disease Control and Prevention (CDC).
2Mali has not reported human cases for four consecutive years (2016-2019) but continued to report indigenous transmission among animals.