Last data update: Apr 28, 2025. (Total: 49156 publications since 2009)
Records 1-24 (of 24 Records) |
Query Trace: Ruiz-Tiben E[original query] |
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Epidemiological and molecular investigations of a point-source outbreak of Dracunculus medinensis infecting humans and dogs in Chad: a cross-sectional study.
Guagliardo SAJ , Thiele E , Unterwegner K , Narcisse Nanguita N , Dossou L , Tchindebet Ouakou P , Zirimwabagabo H , Ruiz-Tiben E , Hopkins DR , Roy SL , Cama V , Bishop H , Sapp S , Yerian S , Weiss AJ . Lancet Microbe 2022 3 (2) e105-e112 ![]() BACKGROUND: Dracunculiasis (also known as Guinea worm disease), caused by the Dracunculus medinensis nematode, is progressing towards eradication, with a reduction in cases from 3·5 million cases in the mid-1980s to only 54 human cases at the end of 2019. Most cases now occur in Chad. On April 19, 2019, a 19-year-old woman presented with D medinensis in an area within the Salamat region of Chad, where the disease had not been previously reported. We aimed to investigate the connection between this case and others detected locally and elsewhere in Chad using a combination of epidemiological and genetic approaches. METHODS: In this cross-sectional field study, we conducted household case searches and informal group interviews in the Bogam, Liwi, and Tarh villages in Chad. All community members including children were eligible for participation in the outbreak investigation. Adult female D medinensis associated with this outbreak were collected for genetic analysis (18 from humans and two from dogs). Four mitochondrial genes and 22 nuclear microsatellite markers were used to assess relatedness of worms associated with the outbreak in comparison with other worms from elsewhere in Chad. FINDINGS: Between April 12 and Sept 6, 2019, we identified 22 human cases and two canine cases of dracunculiasis associated with 15 households. Six (40%) of the 15 affected households had multiple human or canine cases within the household. Most cases of dracunculiasis in people were from three villages in Salamat (21 [95%] of 22 cases), but one case was detected nearly 400 km away in Sarh city (outside the Salamat region). All people with dracunculiasis reported a history of consuming fish and unfiltered water. Worms associated with this outbreak were genetically similar and shared the same maternal lineage. INTERPRETATION: Molecular epidemiological results suggest a point-source outbreak that originated from a single female D medinensis, rather than newly identified sustained local transmission. The failure of the surveillance system to detect the suspected canine infection in 2018 highlights the challenge of canine D medinensis detection, particularly in areas under passive surveillance. Human movement can also contribute to dracunculiasis spread over long distances. FUNDING: The Carter Center. |
Surveillance of Human Guinea Worm in Chad, 2010-2018
Guagliardo SAJ , Ruiz-Tiben E , Hopkins DR , Weiss AJ , Ouakou PT , Zirimwabagabo H , Unterwegner K , Tindall D , Cama VA , Bishop H , Sapp SGH , Roy SL . Am J Trop Med Hyg 2021 105 (1) 188-195 The total number of Guinea worm cases has been reduced by 99.9% since the mid-1980s when the eradication campaign began. Today, the greatest number of cases is reported from Chad. In this report, we use surveillance data collected by the Chad Guinea Worm Eradication Program to describe trends in human epidemiology. In total, 114 human cases were reported during the years 2010-2018, with highest rates of containment (i.e., water contamination prevented) in the years 2013, 2014, 2016, and 2017 (P < 0.0001). Approximately half of case-patients were female, and 65.8% of case-patients were aged 30 years or younger (mean: 26.4 years). About 34.2% of case-patients were farmers. Cases were distributed across many ethnicities, with a plurality of individuals being of the Sara Kaba ethnicity (21.3%). Most cases occurred between the end of June and the end of August and were clustered in the Chari Baguirmi (35.9%) and Moyen Chari regions (30.1%). Cases in the northern Chari River area peaked in April and in August, with no clear pattern in the southern Chari River area. History of travel within Chad was reported in 7.0% of cases, and male subjects (12.5%) were more likely than female subjects (1.7%) to have reported a history of travel (P = 0.03). Our findings confirm that human Guinea worm is geographically disperse and rare. Although the proportion of case-patients with travel history is relatively small, this finding highlights an additional challenge of surveillance in mobile populations in the final stages of the global eradication campaign. |
Correlates of variation in Guinea worm burden among infected domestic dogs
Guagliardo SAJ , Wiegand R , Roy SL , Cleveland CA , Zirimwabagabo H , Chop E , Tchindebet Ouakou P , Ruiz-Tiben E , Hopkins D , Weiss A . Am J Trop Med Hyg 2021 104 (4) 1418-1424 The Guinea Worm Eradication Program has been extraordinarily successful-in 2019, there were 53 human cases reported, down from the estimated 3.5 million in 1986. Yet the occurrence of guinea worm in dogs is a challenge to eradication efforts, and underlying questions about transmission dynamics remain. We used routine surveillance data to run negative binomial regressions predicting worm burden among infected dogs in Chad. Of 3,371 infected dogs reported during 2015-2018, 38.5% had multiple worms. A multivariable model showed that the number of dogs in the household was negatively associated with worm burden (adjusted incidence rate ratio [AIRR] = 0.95, 95% CI: 0.93-0.97, P < 0.0001) after adjusting for dog age (AIRR = 0.99, 95% CI: 0.96-1.01, P > 0.1). This could relate to the amount of infective inocula (e.g., contaminated food or water) shared by multiple dogs in a household. Other significant univariable associations with worm burden included dog history of guinea worm infection (IRR = 1.30, 95% CI: 1.18-1.45) and dog owners who were hunters (IRR = 0.78, 95% CI: 0.62-0.99, P < 0.05) or farmers (IRR = 0.83, 95% CI: 0.77-0.90, P < 0.0001). Further analysis showed that the number of dogs in the household was significantly and positively correlated with nearly all other independent variables (e.g., owner occupation: farmer, fisherman, or hunter; dog age, gender, and history of guinea worm). The associations we identified between worm burden and dogs per household, and dogs per household and owner characteristics should be further investigated with more targeted studies. |
Investigation of dracunculiasis transmission among humans, Chad, 2013-2017
Liu EW , Sircar AD , Matchanga K , Mahamat AM , Ngarhor N , Ouakou PT , Zirimwabagabo H , Ruiz-Tiben E , Sankara D , Wiegand R , Roy SL . Am J Trop Med Hyg 2020 104 (2) 724-730 Dracunculiasis, slated for global eradication, typically is acquired by drinking stagnant water containing microscopic crustaceans (copepods) infected with Dracunculus medinensis larvae, causing clusters of case persons with worms emerging from the skin. Following a 10-year absence of reported cases, 9-17 sporadic human cases with few epidemiologic links have been reported annually in Chad since 2010; dog infections have also been reported since 2012. We conducted an investigation of human cases in Chad to identify risk factors. We conducted a case-control study using a standardized questionnaire to assess water and aquatic animal consumption, and links to dog infections. Case persons had laboratory-confirmed D. medinensis during 2013-2017. Each case person was matched to one to three controls without history of disease by age, gender, and residency in the village where the case person was likely infected. We estimated odds ratios (ORs) using simple conditional logistic regression. We enrolled 25 case persons with 63 matched controls. Dracunculiasis was associated with consumption of untreated water from hand-dug wells (OR: 13.4; 95% CI: 1.7-108.6), but neither with consumption of aquatic animals nor presence of infected dogs in villages. Unsafe water consumption remains associated with dracunculiasis. Education of populations about consuming safe water and using copepod filters to strain unsafe water should continue and expand, as should efforts to develop and maintain safe drinking water sources. Nevertheless, the peculiar epidemiology in Chad remains incompletely explained. Future studies of dogs might identify other risk factors. |
Population genomic evidence that human and animal infections in Africa come from the same populations of Dracunculus medinensis.
Durrant Caroline, Thiele Elizabeth A, Holroyd Nancy, Doyle Stephen R, Sallé Guillaume, Tracey Alan, Sankaranarayanan Geetha, Lotkowska Magda E, Bennett Hayley M, Huckvale Thomas, Abdellah Zahra, Tchindebet Ouakou, Wossen Mesfin, Logora Makoy Samuel Yibi, Coulibaly Cheick Oumar, Weiss Adam, Schulte-Hostedde Albrecht I, Foster Jeremy M, Cleveland Christopher A, Yabsley Michael J, Ruiz-Tiben Ernesto, Berriman Matthew, Eberhard Mark L, Cotton James A. PLoS neglected tropical diseases 2020 Nov 14(11) e0008623 . PLoS neglected tropical diseases 2020 Nov 14(11) e0008623 ![]() ![]() Durrant Caroline, Thiele Elizabeth A, Holroyd Nancy, Doyle Stephen R, Sallé Guillaume, Tracey Alan, Sankaranarayanan Geetha, Lotkowska Magda E, Bennett Hayley M, Huckvale Thomas, Abdellah Zahra, Tchindebet Ouakou, Wossen Mesfin, Logora Makoy Samuel Yibi, Coulibaly Cheick Oumar, Weiss Adam, Schulte-Hostedde Albrecht I, Foster Jeremy M, Cleveland Christopher A, Yabsley Michael J, Ruiz-Tiben Ernesto, Berriman Matthew, Eberhard Mark L, Cotton James A. PLoS neglected tropical diseases 2020 Nov 14(11) e0008623 |
Guinea worm in domestic dogs in Chad: A description and analysis of surveillance data
Guagliardo SAJ , Roy SL , Ruiz-Tiben E , Zirimwabagabo H , Romero M , Chop E , Ouakou PT , Hopkins DR , Weiss AJ . PLoS Negl Trop Dis 2020 14 (5) e0008207 After a ten-year absence of reported Guinea worm disease in Chad, human cases were rediscovered in 2010, and canine cases were first recorded in 2012. In response, active surveillance for Guinea worm in both humans and animals was re-initiated in 2012. As of 2018, the Chad Guinea Worm Eradication Program (CGWEP) maintains an extensive surveillance system that operates in 1,895 villages, and collects information about worms, hosts (animals and humans), and animal owners. This report describes in detail the CGWEP surveillance system and explores epidemiological trends in canine Guinea worm cases during 2015-2018. Our results showed an increased in the number of canine cases detected by the system during the period of interest. The proportion of worms that were contained (i.e., water contamination was prevented) improved significantly over time, from 72.8% in 2015 to 85.7% in 2018 (Mantel-Haenszel chi-square = 253.3, P < 0.0001). Additionally, approximately 5% of owners of infected dogs reported that the dog had a Guinea worm-like infection earlier that year; 12.6% had a similar worm in a previous year. The proportion of dogs with a history of infection in a previous year increased over time (Mantel-Haenszel chi-square = 18.8, P < 0.0001). Canine cases were clustered in space and time: most infected dogs (80%) were from the Chari Baguirmi (38.1%) and Moyen Chari Regions (41.9%), and for each year the peak month of identified canine cases was June, with 78.5% occurring during March through August. Findings from this report evoke additional questions about why some dogs are repeatedly infected. Our results may help to target interventions and surveillance efforts in terms of space, time, and dogs susceptible to recurrent infection, with the ultimate goal of Guinea worm eradication. |
Progress toward global eradication of dracunculiasis - January 2017-June 2018
Hopkins DR , Ruiz-Tiben E , Weiss AJ , Roy SL , Zingeser J , Guagliardo SAJ . MMWR Morb Mortal Wkly Rep 2018 67 (45) 1265-1270 Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is acquired by drinking water containing copepods (water fleas) infected with its larvae. The worm typically emerges through the skin on a lower limb approximately 1 year after infection, causing pain and disability (1). The worldwide eradication campaign began at CDC in 1980. In 1986, the World Health Assembly called for dracunculiasis elimination, and the global Guinea Worm Eradication Program (GWEP), led by the Carter Center in partnership with the World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and others, began assisting ministries of health in countries with dracunculiasis. There is no vaccine or medicine to treat the disease; the GWEP relies on case containment* to prevent water contamination and other interventions to prevent infection, including health education, water filtration, chemical treatment of water, and provision of safe drinking water (1,2). In 1986, an estimated 3.5 million cases(dagger) occurred each year in 20( section sign) African and Asian countries (3,4). This report, based on updated health ministry data (3), describes progress during January 2017-June 2018 and updates previous reports (1,4). In 2017, 30 cases were reported from Chad and Ethiopia, and 855 infected animals (mostly dogs) were reported from Chad, Ethiopia, and Mali, compared with 25 cases and 1,049 animal infections reported in 2016. During January-June 2018, the number of cases declined to three cases each in Chad and South Sudan and one in Angola, with 709 infected animals reported, compared with eight cases and 547 animal infections during the same period of 2017. With only five affected countries, the eradication goal is near, but is challenged by civil unrest, insecurity, and lingering epidemiologic and zoologic questions. |
Population genetic analysis of Chadian Guinea worms reveals that human and non-human hosts share common parasite populations.
Thiele EA , Eberhard ML , Cotton JA , Durrant C , Berg J , Hamm K , Ruiz-Tiben E . PLoS Negl Trop Dis 2018 12 (10) e0006747 ![]() ![]() Following almost 10 years of no reported cases, Guinea worm disease (GWD or dracunculiasis) reemerged in Chad in 2010 with peculiar epidemiological patterns and unprecedented prevalence of infection among non-human hosts, particularly domestic dogs. Since 2014, animal infections with Guinea worms have also been observed in the other three countries with endemic transmission (Ethiopia, Mali, and South Sudan), causing concern and generating interest in the parasites' true taxonomic identity and population genetics. We present the first extensive population genetic data for Guinea worm, investigating mitochondrial and microsatellite variation in adult female worms from both human and non-human hosts in the four endemic countries to elucidate the origins of Chad's current outbreak and possible host-specific differences between parasites. Genetic diversity of Chadian Guinea worms was considerably higher than that of the other three countries, even after controlling for sample size through rarefaction, and demographic analyses are consistent with a large, stable parasite population. Genealogical analyses eliminate the other three countries as possible sources of parasite reintroduction into Chad, and sequence divergence and distribution of genetic variation provide no evidence that parasites in human and non-human hosts are separate species or maintain isolated transmission cycles. Both among and within countries, geographic origin appears to have more influence on parasite population structure than host species. Guinea worm infection in non-human hosts has been occasionally reported throughout the history of the disease, particularly when elimination programs appear to be reaching their end goals. However, no previous reports have evaluated molecular support of the parasite species identity. Our data confirm that Guinea worms collected from non-human hosts in the remaining endemic countries of Africa are Dracunculus medinensis and that the same population of worms infects both humans and dogs in Chad. Our genetic data and the epidemiological evidence suggest that transmission in the Chadian context is currently being maintained by canine hosts. |
Dracunculiasis eradication: Are we there yet
Hopkins DR , Ruiz-Tiben E , Eberhard ML , Weiss A , Withers PC , Roy SL , Sienko DG . Am J Trop Med Hyg 2018 99 (2) 388-395 This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2017. Dracunculiasis (guinea worm disease) has been eliminated from 19 of 21 countries where it was endemic in 1986, when an estimated 3.5 million cases occurred worldwide. Only Chad and Ethiopia reported cases in humans, 15 each, in 2017. Infections of animals, mostly domestic dogs, with Dracunculus medinensis were reported in those two countries and also in Mali. Insecurity and infections in animals are the two main obstacles remaining to interrupting dracunculiasis transmission completely. |
Progress toward global eradication of dracunculiasis, January 2016-June 2017
Hopkins DR , Ruiz-Tiben E , Eberhard ML , Roy SL , Weiss AJ . MMWR Morb Mortal Wkly Rep 2017 66 (48) 1327-1331 Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from contaminated drinking water, the worm emerges through the skin, usually on a lower limb (1). Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. The campaign to eradicate dracunculiasis worldwide began in 1980 at CDC. In 1986, the World Health Assembly called for dracunculiasis elimination,* and the global Guinea Worm Eradication Program, led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund, CDC, and other partners, began assisting ministries of health in countries with endemic dracunculiasis. In 1986, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia (2). Since then, although the goal of eradicating dracunculiasis has not been achieved, considerable progress has been made. Compared with the 1986 estimate, the annual number of reported cases in 2016 has declined by >99%, and cases are confined to three countries with endemic disease. This report updates published (3-4) and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication during January 2016-June 2017. In 2016, a total of 25 cases were reported from three countries (Chad [16], South Sudan [six], Ethiopia [three]), compared with 22 cases reported from the same three countries and Mali in 2015 (Table 1). The 14% increase in cases from 2015 to 2016 was offset by the 25% reduction in number of countries with indigenous cases. During the first 6 months of 2017, the overall number of cases declined to eight, all in Chad, from 10 cases in three countries (Chad [four], South Sudan [four] and Ethiopia [two]) during the same period of 2016. Continued active surveillance, aggressive detection, and appropriate management of cases are essential eradication program components; however, epidemiologic challenges, civil unrest, and insecurity pose potential barriers to eradication. |
Recurrence of Guinea worm disease in Chad after a 10-year absence: Risk factors for human cases identified in 2010-2011
Sreenivasan N , Weiss A , Djiatsa JP , Toe F , Djimadoumaji N , Ayers T , Eberhard M , Ruiz-Tiben E , Roy S . Am J Trop Med Hyg 2017 97 (2) 575-582 A decade after reporting its last case of Guinea worm disease (GWD), a waterborne parasitic disease targeted for eradication, Chad reported 20 confirmed human cases from 17 villages-10 cases in 2010 and 10 cases in 2011. In 2012, the first GWD dog infections were diagnosed. We conducted a case-control study during April-May 2012 to identify human transmission risk factors and epidemiologic links. We recruited 19 cases and 45 controls matched by age, sex, time, and location of exposure based on the case patients' periods of infection 10-14 months earlier. Data were analyzed with simple conditional logistic regression models using Firth penalized likelihood methods. Unusually, GWD did not appear to be associated with household primary water sources. Instead, secondary water sources, used outside the village or other nonprimary sources used at home, were risk factors (matched odds ratio = 38.1, 95% confidence interval = 1.6-728.2). This study highlights the changing epidemiology of GWD in Chad-household primary water sources were not identified as risk factors and few epidemiologic links were identified between the handfuls of sporadic cases per year, a trend that continues. Since this investigation, annual dog infections have increased, far surpassing human cases. An aquatic paratenic host is a postulated mode of transmission for both dogs and humans, although fish could not be assessed in this case-control study due to their near-universal consumption. GWD's evolving nature in Chad underscores the continued need for interventions to prevent both waterborne and potential foodborne transmission until the true mechanism is established. |
Guinea worm (Dracunculus medinensis) infection in a wild-caught frog, Chad
Eberhard ML , Cleveland CA , Zirimwabagabo H , Yabsley MJ , Ouakou PT , Ruiz-Tiben E . Emerg Infect Dis 2016 22 (11) 1961-1962 A third-stage (infective) larva of Dracunculus medinensis, the causative agent of Guinea worm disease, was recovered from a wild-caught Phrynobatrachus francisci frog in Chad. Although green frogs (Lithobates clamitans) have been experimentally infected with D. medinensis worms, our findings prove that frogs can serve as natural paratenic hosts. |
Dogs and Guinea worm eradication
Eberhard ML , Ruiz-Tiben E , Hopkins DR . Lancet Infect Dis 2016 16 (11) 1225-1226 Teresa Galán-Puchades, in her Correspondence on dogs and Guinea worm eradication,1 noted several critical points about the Guinea Worm Eradication Program (GWEP) in Chad. We would like to clarify several of the issues. | Dog infections have been addressed programmatically in Chad for the past 4 and a half years. The situation in Chad is different from previous reports of sporadic Guinea worm infections in dogs. What is not made clear by Galán-Puchade is that human Guinea worm has infected dogs occasionally, but when eliminated from the human population, dog infections disappear.2, 3 By contrast, in Chad, dog infections are probably responsible for the small number of cases in human beings.4 We expect human infections in Chad to stop once transmission of Guinea worms among dogs is interrupted. Lastly, all evidence suggests transmission is not occurring via common drinking water sources, but via a paratenic aquatic host that people and dogs are eating raw or only partly cooked.4 | Previous laboratory studies have shown that dogs (and cats and monkeys) are good experimental hosts for Dracunculus medinensis.5, 6 Hence, the ease with which this infection was established in dogs is not surprising. |
Progress toward global eradication of dracunculiasis - January 2015-June 2016
Hopkins DR , Ruiz-Tiben E , Eberhard ML , Roy SL , Weiss AJ . MMWR Morb Mortal Wkly Rep 2016 65 (40) 1112-1116 Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from drinking contaminated water, the worm emerges through the skin, usually on the leg. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. The campaign to eradicate dracunculiasis worldwide began in 1980 at CDC. In 1986, the World Health Assembly called for dracunculiasis elimination (1), and the global Guinea Worm Eradication Program, led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and other partners, began assisting ministries of health in countries where dracunculiasis was endemic. In 1986, an estimated 3.5 million cases were occurring each year in 20 countries in Africa and Asia (1,2). Since then, although the goal of eradicating dracunculiasis has not been achieved, substantial progress has been made. Compared with the 1986 estimate, the annual number of reported cases in 2015 has been reduced by >99%, and cases are confined to four countries with endemic disease. This report updates published (3-5) and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication during January 2015-June 2016. In 2015, a total of 22 cases were reported from four countries (Chad [nine cases], Mali [five], South Sudan [five], and Ethiopia [three]), compared with 126 cases reported in 2014 from the same four countries (Table 1). The overall 83% reduction in cases from 2014 to 2015 is the largest such annual overall reduction ever achieved during this global campaign. During the first 6 months of 2016, however, cases increased 25% compared with the same period in 2015. Continued active surveillance and aggressive detection and appropriate management of cases are essential eradication program components; however, epidemiologic challenges and civil unrest and insecurity pose potential barriers to eradication. |
Possible role of fish and frogs as paratenic hosts of Dracunculus medinensis, Chad
Eberhard ML , Yabsley MJ , Zirimwabagabo H , Bishop H , Cleveland CA , Maerz JC , Bringolf R , Ruiz-Tiben E . Emerg Infect Dis 2016 22 (8) 1428-30 Copepods infected with Dracunculus medinensis larvae collected from infected dogs in Chad were fed to 2 species of fish and tadpoles. Although they readily ingested copepods, neither species of fish, Nile tilapia (Oreochromis niloticus) nor fathead minnow (Pimephalis promelas), were found to harbor Dracunculus larvae when examined 2-3 weeks later. Tadpoles ingested copepods much more slowly; however, upon examination at the same time interval, tadpoles of green frogs (Lithobates [Rana] clamitans) were found to harbor small numbers of Dracunculus larvae. Two ferrets (Mustela putorius furo) were fed fish or tadpoles that had been exposed to infected copepods. Only the ferret fed tadpoles harbored developing Dracunculus larvae at necropsy 70-80 days postexposure. These observations confirm that D. medinensis, like other species in the genus Dracunculus, can readily survive and remain infective in potential paratenic hosts, especially tadpoles. |
Progress toward global eradication of Dracunculiasis, January 2014-June 2015
Hopkins DR , Ruiz-Tiben E , Eberhard ML , Roy SL . MMWR Morb Mortal Wkly Rep 2015 64 (41) 1161-1165 Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from contaminated drinking water, the worm emerges through the skin, usually on the lower limb. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. The campaign to eradicate dracunculiasis worldwide began in 1980 at CDC. In 1986, the World Health Assembly called for dracunculiasis elimination, and the global Guinea Worm Eradication Program, led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and other partners, began assisting ministries of health in countries where dracunculiasis was endemic. In 1986, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia. Since then, although the goal of eradicating dracunculiasis has not been achieved, considerable progress has been made. Compared with the 1986 estimate, the annual number of reported cases in 2015 has been reduced by 99% and cases are confined to four endemic countries. This report updates published and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication from January 2014 through June 2015. During 2014, a total of 126 cases were reported from four countries (Chad [13 cases], Ethiopia [three], Mali [40], and South Sudan [70]), compared with 148 cases reported in 2013, from the same four countries. The overall 15% reduction in cases during 2013-2014 was less than that experienced in recent years, but the rate of decline increased again to 70% in the first 6 months of 2015 compared with the same period during 2014. Continued active surveillance with aggressive detection and appropriate management of cases are essential program components; however, epidemiologic challenges and civil unrest and insecurity pose potential barriers to eradication. |
Thirty-seven human cases of sparganosis from Ethiopia and South Sudan caused by Spirometra spp
Eberhard ML , Thiele EA , Yembo GE , Yibi MS , Cama VA , Ruiz-Tiben E . Am J Trop Med Hyg 2015 93 (2) 350-355 Thirty-seven unusual specimens, three from Ethiopia and 34 from South Sudan, were submitted since 2012 for further identification by the Ethiopian Dracunculiasis Eradication Program (EDEP) and the South Sudan Guinea Worm Eradication Program (SSGWEP), respectively. Although the majority of specimens emerged from sores or breaks in the skin, there was concern that they did not represent bona fide cases of Dracunculus medinensis and that they needed detailed examination and identification as provided by the World Health Organization Collaborating Center (WHO CC) at Centers for Disease Control and Prevention (CDC). All 37 specimens were identified on microscopic study as larval tapeworms of the spargana type, and DNA sequence analysis of seven confirmed the identification of Spirometra sp. Age of cases ranged between 7 and 70 years (mean 25 years); 21 (57%) patients were male and 16 were female. The presence of spargana in open skin lesions is somewhat atypical, but does confirm the fact that populations living in these remote areas are either ingesting infected copepods in unsafe drinking water or, more likely, eating poorly cooked paratenic hosts harboring the parasite. |
Progress toward global eradication of dracunculiasis - January 2013-June 2014
Hopkins DR , Ruiz-Tiben E , Eberhard ML , Roy SL . MMWR Morb Mortal Wkly Rep 2014 63 (46) 1050-4 Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from contaminated drinking water, the worm will emerge through the skin, usually on the lower limb. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. In 1986, the World Health Assembly called for dracunculiasis elimination. The global Guinea Worm Eradication Program, supported by The Carter Center, World Health Organization (WHO), UNICEF, CDC, and other partners, began assisting ministries of health of countries in which dracunculiasis is endemic in meeting this goal. At that time, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia. This report updates published (3-5) and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication. A total of 148 cases were reported in 2013 from five countries (in order of prevalence: South Sudan, Chad, Mali, Ethiopia, and Sudan) compared with 542 cases in 2012 from four countries (South Sudan, Chad, Mali, and Ethiopia). The disease remains endemic in four countries in 2014 (South Sudan, Chad, Mali, and Ethiopia), but the overall incidence is falling faster in 2013 compared with 2012 (by 73%) and continues to fall faster in the first 6 months of 2014 (by 71%) compared with the same period in 2013. Failures in surveillance and containment, lack of clean drinking water, insecurity in Mali and parts of South Sudan, and an unusual epidemiologic pattern in Chad are the main remaining challenges to dracunculiasis eradication. |
Logistics of Guinea worm disease eradication in South Sudan
Jones AH , Becknell S , Withers PC , Ruiz-Tiben E , Hopkins DR , Stobbelaar D , Makoy SY . Am J Trop Med Hyg 2014 90 (3) 393-401 From 2006 to 2012, the South Sudan Guinea Worm Eradication Program reduced new Guinea worm disease (dracunculiasis) cases by over 90%, despite substantial programmatic challenges. Program logistics have played a key role in program achievements to date. The program uses disease surveillance and program performance data and integrated technical-logistical staffing to maintain flexible and effective logistical support for active community-based surveillance and intervention delivery in thousands of remote communities. Lessons learned from logistical design and management can resonate across similar complex surveillance and public health intervention delivery programs, such as mass drug administration for the control of neglected tropical disease and other disease eradication programs. Logistical challenges in various public health scenarios and the pivotal contribution of logistics to Guinea worm case reductions in South Sudan underscore the need for additional inquiry into the role of logistics in public health programming in low-income countries. |
Cutaneous emergence of Eustrongylides in two persons from South Sudan
Eberhard ML , Ruiz-Tiben E . Am J Trop Med Hyg 2013 90 (2) 315-7 Two large, living worms were collected as they emerged from the lower limb of each of two persons in South Sudan. The worms were observed by staff of the South Sudan Guinea Worm Eradication Program during surveillance activities in communities at-risk for cases of Guinea worm disease (dracunculiasis). The worms measured 7 and 8 cm in length and were identified as fourth-stage larvae of Eustrongylides. This is the first report of such worms emerging from the skin; all five previous reports of human infection involved surgical removal of worms from the peritoneal cavity. |
The Peculiar epidemiology of dracunculiasis in Chad
Eberhard ML , Ruiz-Tiben E , Hopkins DR , Farrell C , Toe F , Weiss A , Withers PC Jr , Jenks MH , Thiele EA , Cotton JA , Hance Z , Holroyd N , Cama VA , Tahir MA , Mounda T . Am J Trop Med Hyg 2013 90 (1) 61-70 Dracunculiasis was rediscovered in Chad in 2010 after an apparent absence of 10 years. In April 2012 active village-based surveillance was initiated to determine where, when, and how transmission of the disease was occurring, and to implement interventions to interrupt it. The current epidemiologic pattern of the disease in Chad is unlike that seen previously in Chad or other endemic countries, i.e., no clustering of cases by village or association with a common water source, the average number of worms per person was small, and a large number of dogs were found to be infected. Molecular sequencing suggests these infections were all caused by Dracunculus medinensis. It appears that the infection in dogs is serving as the major driving force sustaining transmission in Chad, that an aberrant life cycle involving a paratenic host common to people and dogs is occurring, and that the cases in humans are sporadic and incidental. |
Dracunculiasis eradication: and now, South Sudan
Hopkins DR , Ruiz-Tiben E , Weiss A , Withers PC Jr , Eberhard ML , Roy SL . Am J Trop Med Hyg 2013 89 (1) 5-10 Abstract. This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2012. Dracunculiasis (Guinea worm disease) has been eliminated from 17 of 21 countries where it was endemic in 1986, when an estimated 3.5 million cases occurred worldwide. Only 542 cases were reported from four countries in 2012, and 103 villages still had indigenous transmission. Most remaining cases were reported from the new Republic of South Sudan, whereas Chad, Ethiopia, and Mali each reported 10 cases or less. Political instability and insecurity in Mali may become the main obstacles to interrupting dracunculiasis transmission forever. |
Emergence of Onchocerca volvulus from skin mimicking Dracunculiasis medinensis
Eberhard ML , Ruiz-Tiben E , Korkor AS , Roy SL , Downs P . Am J Trop Med Hyg 2010 83 (6) 1348-51 We describe 11 cases of suspected Dracunculus medinensis infection in which the worm recovered was identified as Onchocerca volvulus. Identification was based on morphology of the examined specimen. |
Guinea worm disease outcomes in Ghana: determinants of broken worms
Glenshaw MT , Roy S , Ruiz-Tiben E , Downs P , Williamson J , Eberhard M . Am J Trop Med Hyg 2009 81 (2) 305-12 In 2006, Ghana ranked second in Guinea worm disease (GWD) incidence and reported a previously undocumented 20% prevalence of worm breakage. A prospective study was conducted in 2007 to validate and describe worm breakage and determinants. Among 221 patients with known outcomes, the worm breakage rate observed was 46%. After controlling for demographics, worm and wound presentation, and treatment course and provision, worm breakage was associated with narrow-diameter worms (< 2 mm) (adjusted odds ratio [AOR] 2.79; 95% confidence interval [CI] = 1.03-7.53). Protective factors against worm breakage included antibiotic ointment use (AOR 0.31; 95% CI = 0.14-0.70), bandage protocol compliance (AOR: 0.38; 95% CI = 0.16-0.89), intact bandages (AOR 0.27; 95% CI = 0.09-0.82), and bloody compared with dry wounds (AOR 0.09; 95% CI = 0.01-0.7). The high worm breakage rate observed warrants improvement in case management and patient care. Adherence to established treatment protocols should be facilitated through improved provider training and supervision to reduce the disabling consequences of broken worms. |
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