viernes, 26 de octubre de 2012

Progress Toward Global Eradication of Dracunculiasis — January 2011–June 2012

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Progress Toward Global Eradication of Dracunculiasis — January 2011–June 2012

Progress Toward Global Eradication of Dracunculiasis — January 2011–June 2012


October 26, 2012 / 61(42);854-857

Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after initial infection from contaminated drinking water, the worm emerges through the skin of the infected person, usually on the lower limb. Pain and secondary bacterial wound infection can cause temporary or permanent disability that disrupts work and schooling for the entire family. In 1986, the World Health Assembly (WHA) called for dracunculiasis elimination (1) and the Guinea Worm Eradication Program, supported by The Carter Center, World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and other partners, was coalesced to assist ministries of health of endemic countries in meeting this goal. At that time, an estimated 3.5 million cases occurred annually in 20 countries in Africa and Asia (1,2). This report updates published (3,4) and previously unpublished surveillance data reported by ministries of health and describes progress toward global dracunculiasis eradication. In 2011, a total of 1,058 cases were reported. As of 2012, dracunculiasis remained endemic in only four countries. Through June 2012, worldwide reductions in reported cases continued, compared with the first 6 months of 2011. Failures in surveillance and containment, lack of clean drinking water, and insecurity in Mali and parts of South Sudan continue to challenge dracunculiasis eradication efforts.
Considerable progress has been made since 1986 in reducing the annual number of reported dracunculiasis cases. The 1991 WHA goal to eradicate dracunculiasis globally by 1995 was not achieved because of the limited funding then available from international organizations for support of technical and financial assistance to countries with endemic disease, and the limited time (4 years) to meet the WHA goal (5). In 2004, WHA established a new target date of 2009 for global eradication (6). Despite considerable progress, that target date also was not met. Nevertheless, progress toward eradication continues. The number of cases of dracunculiasis worldwide reported by disease endemic countries to WHO and partner organizations decreased 41%, from 1,797 cases in 2010 to 1,058 in 2011. As of June 2012, dracunculiasis remained endemic in four countries (Chad, Ethiopia, Mali, and South Sudan). The 395 cases reported and 219 villages reporting cases globally during January–June 2012 represent reductions of 51% and 39%, respectively, from the 807 cases reported and 358 villages that reported cases during January–June 2011. Of the 395 cases reported during January–June 2012, 99% were from South Sudan.
As a result of having an indigenous case* in 2012 for the third consecutive year following discovery of cases in 2010, Chad officially became endemic for dracunculiasis again. Ethiopia and Mali have reported two cases and one case, respectively, in the first 6 months of 2012. Active surveillance conducted by national eradication programs for cases in known endemic areas improved in Chad and deteriorated in Mali during January–June 2012.
In December 2011, WHO certified two additional, formerly endemic countries, Burkina Faso and Togo, as having eliminated dracunculiasis (i.e., zero cases reported for ≥36 consecutive months), based on the recommendation of the International Commission for the Certification of Dracunculiasis Eradication. As required by the resolution on eradication of dracunculiasis (WHA64.16) that was adopted by the WHA in May 2011 (7), the secretariat of WHO provided its first annual report regarding this eradication campaign to WHA in May 2012. The current target is to interrupt transmission in all four remaining countries as soon as possible. Currently, insecurity (e.g., sporadic violence or civil unrest) in parts of South Sudan, and especially Mali, poses the greatest threat to the success of the global dracunculiasis eradication campaign.
Persons become infected with the parasite by drinking water from stagnant sources (e.g., ponds) containing copepods (water fleas) that harbor D. medinensis larvae. No effective drug to treat or vaccine to prevent the disease is available, and persons who contract D. medinensis infections do not become immune. After a 1-year incubation period, adult female worms 24–40 inches (60–100 cm) long migrate under the skin and emerge, usually through the skin of the person's foot or lower leg. On contact with water, these worms release larvae that can then be ingested by copepods in the water and infect persons who drink the water. The emerging worm can be removed by manual traction and rolling it up on a stick or gauze a few centimeters each day. Complete removal requires an average of approximately 4 weeks. Disabilities caused by dracunculiasis are secondary to bacterial infections that develop at the site of worm emergence, which might lead to septicemia, and can result in debilitating pain and swelling, tetanus, arthritis, and contractures of the involved limb (8,9).
Dracunculiasis can be prevented by 1) educating residents in disease-endemic communities, and particularly persons from whom worms are emerging, to avoid immersing affected parts in sources of drinking water, 2) filtering potentially contaminated drinking water through a cloth filter, 3) treating potentially contaminated surface water with the larvicide temephos (Abate), and 4) providing safe drinking water from bore-hole or hand-dug wells (5). Containment of transmission, achieved through 1) voluntary isolation of each patient to prevent contamination of drinking water sources, 2) provision of first aid, 3) manual extraction of the worm, and 4) application of occlusive bandages, is complementary to the four main interventions.
Countries enter the WHO precertification stage of eradication after completing 1 full calendar year without reporting any indigenous cases (i.e., one incubation period for D. medinensis). A case of dracunculiasis is defined as occurring in a person exhibiting a skin lesion or lesions with emergence of one or more Guinea worms. Each person is counted as a case only once during a calendar year. An imported case is an infection acquired in a place (another country or village within the same country) other than the community where it is detected and reported. Six countries where transmission of dracunculiasis previously was endemic (Cote d'Ivoire, Ghana, Kenya, Niger, Nigeria, and Sudan§) are in the precertification stage of eradication.
In each country affected by dracunculiasis, a national eradication program receives monthly reports of cases from each village that has endemic transmission. Reporting rates are calculated by dividing the number of villages with endemic dracunculiasis that report each month by the total number of villages with endemic disease. All villages with endemic dracunculiasis are kept under active surveillance, with daily searches of households for persons with signs and symptoms suggestive of dracunculiasis. These are conducted to ensure that detection occurs within 24 hours of worm emergence so that patient management can begin to prevent contamination of water. Villages where endemic transmission of dracunculiasis is interrupted (i.e., zero cases reported for ≥12 consecutive months) also are kept under active surveillance for 3 consecutive years.
WHO certifies a country free from dracunculiasis after that country maintains adequate nationwide surveillance for 3 consecutive years and demonstrates that no cases of indigenous dracunculiasis occurred during that period. As of the end of 2011, WHO had certified 192 countries and territories as free from dracunculiasis (3); 14 countries, including four with endemic disease, remain to be certified.
Country Reports
South Sudan. The 10 southern states of the former Sudan became the independent Republic of South Sudan on July 9, 2011. The area of South Sudan reported all of the indigenous cases notified from the former Sudan since 2002. The South Sudan Guinea Worm Eradication Program (SSGWEP) reported 1,028 cases in 2011, of which 763 (74%) were contained (Table 1), which was a reduction of 39% from the 1,698 cases reported in 2010. For January–June 2012, SSGWEP reported a provisional total of 391 cases (66% contained) from 215 villages, compared with 794 cases (75% contained) reported from 358 villages during January–June 2011; a reduction of 51% in cases and 40% in the number of villages reporting cases (Table 2). Of all cases in South Sudan in the first 6 months of 2012, 81% were reported from only one county, Kapoeta East County in Eastern Equatoria State. In May 2012, the collapse of a key bridge on the only available road for transporting SSGWEP supplies and materials and humanitarian aid to communities in the eastern end of this county added a challenge to efforts to eradicate dracunculiasis in South Sudan. SSGWEP also faces on-going challenges in the seasonal movements of different age and gender groups among villages, gardens, farms, bull cattle camps, milking cow cattle camps, and grazing areas for smaller livestock, such as goats, plus unpredictable population displacements from interethnic cattle rustling raids. The program has continued to intensify interventions (e.g., temephos was used in 60% of endemic villages in 2010, 85% in 2011, and 96% in January–June 2012) and supervision (e.g., 45 national program officers and technical assistants in 2010, 58 in 2011, and 70 in 2012). The peak transmission season in South Sudan is March–July.
Mali. Mali's Guinea Worm Eradication Program reported 12 indigenous cases in 2011, which was a reduction of 79% from the 57 indigenous cases reported in 2010. Only five (42%) of the cases reported in 2011 were contained. One case, which was contained, was reported from Mali in January–June 2012, compared with three cases (one contained) reported in January–June 2011. This program suffered a severe setback because of a coup d'etat in March 2012, as a result of which subsequent reports include only four southern regions of the country. As of April 2012, Mali's Guinea Worm Eradication Program has not been operational in three endemic northern regions (Timbuktu, Gao, and Kidal). Mali's peak Guinea worm transmission season is June–October.
Ethiopia. After 9 consecutive months with no known cases, Ethiopia reported one case in April and one case in May 2012. Only one of the cases was contained. Both cases in 2012 were linked to a case that occurred in one disease-endemic village in April–May 2011. Ethiopia reported eight cases in January–June 2011, of which seven cases were reportedly contained, and no cases in July–December 2011. This was a reduction of 60% from the 20 indigenous cases reported during 2010. All of the cases in 2011 and one of the cases in 2012 were from Gog District of Gambella Region. The other case in 2012 was from an adjacent district in the same region. The peak transmission season in Ethiopia is March–May.
Chad. After a decade with no reported cases, a visiting team from WHO investigated rumors of cases in 2010 and confirmed cases in Chad that eventually numbered 10 known cases (none contained) in eight villages during 2010 (10). Another 10 cases (four contained) were reported in nine other villages in 2011. The origin of these cases is unknown. Specimens taken from several patients in 2010 and 2011 were confirmed at CDC as D. medinensis. Chad reported one case, which was not contained, in June 2012, compared with two cases (one contained) reported during January–June 2011. The case of dracunculiasis in 2012 is the first since 2010 that can be linked in time and place to a case in the preceding year. As a result of 3 continuous years of transmission, Chad met the definition for reestablishment of endemic transmission of dracunculiasis in a country. By the end of May 2012, The Carter Center had helped the ministry of health to train 1,388 village volunteers and 180 supervisors to conduct active surveillance in the 723 at-risk villages associated with the cases in 2010–2012. The peak transmission season in Chad appears to be June–August.

Reported by

Ernesto Ruiz-Tiben, PhD, The Carter Center, Atlanta, Georgia. Mark L. Eberhard, Div of Parasitic Diseases and Malaria, Center for Global Health; Sharon L. Roy, Div of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases; World Health Organization Collaborating Center for Research, Training, and Eradication of Dracunculiasis; CDC. Corresponding contributor: Sharon L. Roy,, 404-718-4698.

Editorial Note

Approximately $72 million in new pledges to the Guinea Worm Eradication Program were announced in 2011–2012 by the United Kingdom's Department for International Development, the Bill & Melinda Gates Foundation, His Highness Sheikh Khalifa bin Zayed Al Nayan of the United Arab Emirates, and the Children's Investment Fund Foundation. Together, those pledges completed the estimated remaining funding needed for The Carter Center's assistance to endemic countries for completing interruption of transmission, and for WHO's assistance to countries for surveillance during and after elimination of transmission and for certification of eradication.
Based on reported trends from 2011, during which three quarters of all cases of dracunculiasis were reported during the first half of that year, fewer than 500 cases likely will be reported globally for all of 2012, setting the stage for an all-out effort to stop transmission from every case that occurs in 2013. The main programmatic challenges requiring urgent attention by governments and partners include 1) failures in surveillance and containment (e.g., missed cases, unexplained sources of cases, and uncontained cases), 2) establishment and maintenance of surveillance in Guinea worm-free areas of all countries where the disease still occurs or was recently eliminated, and 3) providing clean drinking water quickly to as many targeted villages as possible. Insecurity in much of the endemic areas of Mali is now the main political barrier to complete eradication of dracunculiasis.


  1. World Health Assembly. Resolution WHA 39.21. Elimination of dracunculiasis: resolution of the 39th World Health Assembly. Geneva, Switzerland: World Health Organization; 1986. Available at Adobe PDF fileExternal Web Site Icon. Accessed October 19, 2012.
  2. Watts SJ. Dracunculiasis in Africa: its geographic extent, incidence, and at-risk population. Am J Trop Med Hyg 1987;37:119–25.
  3. World Health Organization. Dracunculiasis eradication: global surveillance summary, 2011. Wkly Epidemiol Rec 2012;87:177–88.
  4. CDC. Progress toward global eradication of dracunculiasis, January 2010–June 2011. MMWR 2011;60:1450–3.
  5. Ruiz-Tiben E, Hopkins DR. Dracunculiasis (Guinea worm disease) eradication. Adv Parasitol 2006;61:275–309.
  6. World Health Assembly. Resolution WHA 57.9. Elimination of dracunculiasis: resolution of the 57th World Health Assembly. Geneva, Switzerland: World Health Organization; 2004. Additional information available at Adobe PDF fileExternal Web Site Icon. Accessed October 19, 2012.
  7. World Health Assembly. Resolution WHA 64.16. Eradication of dracunculiasis: resolution of the 64th World Health Assembly. Geneva, Switzerland: World Health Organization; 2011. Available at: Adobe PDF fileExternal Web Site Icon. Accessed October 19, 2012.
  8. Imtiaz R, Hopkins DR, Ruiz-Tiben E. Permanent disability from dracunculiasis. Lancet 1990;336:630.
  9. Ruiz-Tiben E, Hopkins DR. Dracunculiasis. In: Guerrant RL, Walker DH, Weller PF, eds. Tropical infectious diseases: principles, pathogens, and practice. 2nd ed. New York, NY: Elsevier; 2006:1204–7.
  10. CDC. Renewed transmission of dracunculiasis—Chad, 2010. MMWR 2011;60:744–8.

* An indigenous case is defined as a Guinea worm protruding through a lesion on the skin in a person who had no history of travel outside his or her residential locality during the preceding year.
Transmission from a patient with dracunculiasis is contained if all of the following conditions are met: 1) the disease is detected <24 2="2" 3="3" 4="4" 7="7" a="a" achieved="achieved" after="after" all="all" and="and" any="any" are="are" bandaging="bandaging" be="be" been="been" by="by" case="case" cleaning="cleaning" considered="considered" contained.="contained." contained="contained" containment="containment" contaminating="contaminating" criteria="criteria" days="days" discourage="discourage" dracunculiasis="dracunculiasis" each="each" education="education" emerged="emerged" emergence="emergence" emerging="emerging" entered="entered" for="for" from="from" fully="fully" has="has" health="health" hours="hours" if="if" including="including" is="is" last="last" lesion="lesion" managed="managed" manually="manually" more="more" must="must" not="not" of="of" or="or" p="p" patient="patient" present="present" process="process" properly="properly" providing="providing" removed="removed" since="since" source="source" supervisor="supervisor" the="the" these="these" to="to" transmission="transmission" two="two" until="until" validated="validated" verification="verification" volunteer="volunteer" water="water" within="within" worm.="worm." worm="worm" worms="worms">
§ On July 9, 2011, the former country of Sudan officially separated into two countries: the Republic of the Sudan and the Republic of South Sudan. Currently, South Sudan is endemic for dracunculiasis. The area comprising the new country of Sudan, located north of South Sudan, has been free from dracunculiasis since 2002.
A country will be considered to have established or reestablished dracunculiasis endemicity if 1) the country has not reported a confirmed indigenous case of the disease for >3 years, and 2) subsequent indigenous transmission of cases (laboratory-confirmed) is shown to occur in that country for ≥3 consecutive calendar years.

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