Latest situation: January – August 2016
Of the four countries where dracunculiasis remains endemic (Chad, Ethiopia, Mali and South Sudan), only one country (Mali) has not reported cases in humans during January–August 2016.
During this period 13 cases have been reported from eleven villages compared with 14 cases in 14 villages in 2015 during the same period.
A cumulative total of 700 dogs infected with Dracunculus medinensis have been reported from 186 villages in 13 districts and 4 regions.
Of the 15810 rumours and suspected cases reported from the four endemic countries and the two countries in the precertification phase, 99% were investigated within 24 hours. Most of the rumours were reported from Ethiopia and South Sudan.
Global burden, 2015
The global burden of dracunculiasis has fallen significantly since the launch of eradication efforts in the 1980s when 20 countries were endemic for the disease.
In 1986, an estimated 3.5 million new cases occurred.
In 1989, based on active village-based searches, 892 055 cases were reported to have occurred in 15 of the 20 endemic countries (excluding data from Chad, the Central African Republic, Senegal and Sudan).
In 2015, the disease was confined to the four endemic countries, when a total of 22 cases were reported, a reduction of 83% compared with the 126 cases reported in 2014 and a more than 99% reduction from the number of cases reported in 1989. South Sudan reported 5 cases, or 23% of the global total compared with 55% in 2014; most of the cases were reported from Chad, followed by Mali (5 cases) and Ethiopia (3 cases).
The number of villages reporting cases reduced from 20 localities/villages in 2015 to 54 in 2014; a 63% reduction.
Of the 22 cases reported in 2015, 59% were male. Similarly 59% of cases were children aged less than 15 years.
In Chad, the outbreak that was first detected in 2010 continued into its sixth year in 2015. Chad was reclassified as a country endemic for the disease in 2012. A total of 9 new indigenous cases were reported from nine villages of eight districts in five regions in 2015. None of the nine villages had reported cases in previous years (2012–2014).None of the 66 cases reported in 2010–2015 had a history of travel outside Chad.
Sporadic, dispersed human cases have been accompanied by increasingly large numbers of infected dogs along the Chari River basin. In 2015, a total of 503 infected dogs were reported compared with 113 in 2014, 54 in 2013 and 27 in 2012.
As of 31 December 2015, 196 countries, territories, and areas have been certified free of dracunculiasis transmission. Nine countries remain to be certified, of which two countries (Angola and the Democratic Republic of the Congo) have no recent history of dracunculiasis. The six other countries are either endemic (Chad, Ethiopia, Mali and South Sudan) or in the precertification phase (Kenya and Sudan).
Endemic countries situation
Precertified countries situation
The 83% reduction in the number of cases reported in 2015 marks the first year ever of two-digit numbers of cases. The one digit number for South Sudan is a remarkable achievement.
However, the large number of infected dogs reported in Chad is a challenge. Intermittent insecurity in certain areas of Chad, the Central African Republic, Ethiopia and Kenya, the northern part of Mali, South Sudan and the southern part of Sudan has hindered surveillance and programme implementation.
In March 2016, WHO convened the eleventh meeting of the Commission (ICCDE 11) and a ‘Scientific Meeting to address the Guinea Worm Disease infection in dogs’. The meetings were attended by ICCDE members and additional experts on dracunculiasis eradication, molecular biology and veterinary public health.
The Scientific Meeting recommended the following priority research areas:
- Conduct case–control studies of (post-containment) infected dogs, and appropriate paired controls, using novel technologies including GPS tracking and stable isotope analyses, to understand foraging, ranging and other correlates of infection risk;
- Develop the case for a serological assay to detect D. medinensis antibodies in dogs and humans;
- Explore what ecological changes have occurred; explore ecological factors of villages heavily infected (dogs) versus villages not infected (dogs); and remote sensing/mapping of water sources combined with local knowledge of change of water bodies over time;
- Model the pattern of human cases over time with 14-month history of movement before worm emergence; enhance case investigation and travel history of all cases;
- Evaluate case containment strategies for dogs; extend the amount of time the dog will be chained; assess alternative interventions to prevent transmission from and to dogs (provision of food and safe water);
- Design a tool that will identify which water sources harbour infected copepods;
- Develop and implement serological protocols to evaluate disease transmission dynamics in dogs and humans, identify potential new areas of exposure to D. medinensis and monitor intervention responses (e.g. treatment with ivermectin).