ABSTRACT
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 temporal pattern in the southern Chari River area. History of travel within Chad was reported in 7.0% of cases, and male case-patients (12.5%) were more likely than female case-patients (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 the challenge of surveillance in mobile populations in the final stages of the global eradication campaign.
Subject(s)
Disease Eradication/statistics & numerical data , Disease Eradication/trends , Dracunculiasis/epidemiology , Dracunculiasis/physiopathology , Dracunculus Nematode/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Chad/epidemiology , Epidemiologic Methods , Female , Forecasting , Humans , Male , Middle Aged , Population Surveillance , Young AdultABSTRACT
Guinea worm (GW) disease, caused by Dracunculus medinensis, is an almost eradicated waterborne zoonotic disease. The World Health Organization (WHO) currently lists GW as endemic in only five African countries. In July 2020, the Vietnamese public health surveillance system detected a hanging worm in a 23-year-old male patient, who did not report any travel to Africa or any country previously endemic for GW. The patient was hospitalized with symptoms of fatigue, anorexia, muscle aches, and abscesses, with worms hanging out of the skin in the lower limbs. The worms were retrieved from the lesions and microscopically examined in Vietnam, identifying structures compatible with Dracunculus spp. and L1-type larvae. A section of this parasite was sent to the Centers for Disease Control and Prevention (CDC) in Atlanta, United States, for confirmatory diagnosis of GW. The adult worm had cuticle structures compatible with Dracunculus parasites, although the length of L1 larvae was about 339 µm, substantially shorter than D. medinensis. DNA sequence analysis of the 18S small subunit rRNA gene confirmed that this parasite was not GW, and determined that the sample belonged to a Dracunculus sp. not previously reported in GenBank that clustered with the animal-infective Dracunculus insignis and Dracunculus lutrae, located in a different clade than D. medinensis. This study highlights the importance of effective public health surveillance systems and the collaborative work of local public health authorities from Vietnam with the WHO and CDC in efforts to achieve the eradication of GW.
Subject(s)
Dracunculiasis/diagnosis , Dracunculus Nematode/classification , Dracunculus Nematode/genetics , Animals , Anthelmintics/therapeutic use , Dracunculiasis/drug therapy , Dracunculiasis/parasitology , Dracunculus Nematode/isolation & purification , Humans , Larva/classification , Larva/genetics , Male , Public Health Surveillance , Thiabendazole/therapeutic use , Treatment Outcome , Vietnam , Waterborne Diseases/diagnosis , Young AdultABSTRACT
BACKGROUND: Guinea worm is a debilitating parasitic infection targeted for eradication. Annual human cases have dropped from approximately 3,500,000 in 1986 to 54 in 2019. Recent identification of canine cases in Chad threatens progress, and therefore detection, prevention, and containment of canine cases is a priority. We investigated associations between disease knowledge, community engagement, and canine cases in Chad to identify opportunities to improve active surveillance. METHODS: We surveyed 627 respondents (villagers, local leaders, community volunteers, and supervisors) across 45 villages under active surveillance. Descriptive statistics were analyzed by respondent category. Logistic regression models were fitted to assess the effects of volunteer visit frequency on villager knowledge. RESULTS: Knowledge increased with respondents' associations with the Guinea worm program. Household visit frequency by community volunteers was uneven: 53.0% of villagers reported visits at least twice weekly and 21.4% of villagers reported never being visited. Villagers visited by a volunteer at least twice weekly had better knowledge of Guinea worm symptoms (OR: 1.71; 95% CI: 1.04-2.79) and could name more prevention strategies (OR: 2.04; 95% CI: 1.32-3.15) than villagers visited less frequently. The primary motivation to report was to facilitate care-seeking for people with Guinea worm. Knowledge of animal "containment" to prevent contamination of water, knowledge of rewards for reporting animal cases, and ability to name any reasons to report Guinea worm were each positively correlated with village canine case counts. CONCLUSIONS: Community volunteers play crucial roles in educating their neighbors about Guinea worm and facilitating surveillance. Additional training and more attentive management of volunteers and supervisors could increase visit frequency and further amplify their impact. Emphasizing links between animal and human cases, the importance of animal containment, and animal rewards might improve surveillance and canine case detection. The surveillance system should be evaluated routinely to expand generalizability of data and monitor changes over time.
Subject(s)
Dog Diseases/epidemiology , Dracunculiasis/epidemiology , Dracunculiasis/veterinary , Health Knowledge, Attitudes, Practice , Primary Prevention/methods , Adult , Animals , Chad/epidemiology , Dog Diseases/parasitology , Dogs , Dracunculus Nematode/isolation & purification , Female , Humans , Male , Middle Aged , Patient Education as Topic , Primary Prevention/education , Surveys and QuestionnairesABSTRACT
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, sex, 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.
Subject(s)
Animals, Domestic/parasitology , Dog Diseases/parasitology , Dogs/parasitology , Dracunculiasis/veterinary , Dracunculus Nematode/isolation & purification , Parasite Load/methods , Animals , Chad/epidemiology , Dog Diseases/epidemiology , Dracunculiasis/epidemiology , Family Characteristics , Female , Male , Parasite Load/statistics & numerical data , Regression Analysis , Risk FactorsSubject(s)
Disease Eradication/methods , Dracunculiasis/prevention & control , Drinking Water/parasitology , Endemic Diseases/prevention & control , Africa/epidemiology , Animals , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/transmission , Disease Eradication/organization & administration , Disease Reservoirs/parasitology , Dogs , Dracunculiasis/epidemiology , Dracunculiasis/parasitology , Dracunculiasis/transmission , Dracunculus Nematode/isolation & purification , Dracunculus Nematode/parasitology , Drinking Water/analysis , Endemic Diseases/statistics & numerical data , Health Knowledge, Attitudes, Practice , Health Policy/legislation & jurisprudence , Health Promotion , Humans , Incidence , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purificationABSTRACT
The prevalence and diversity of parasitic nematodes in wildlife have been well studied for certain species, yet for others considerable gaps in knowledge exist. The parasitic nematode Dracunculus insignis infects North American wildlife, and past research on this species has led to an increased understanding of the potential host diversity and transmission of the closely related human Guinea worm, Dracunculus medinensis (which is currently the focus of a global eradication program). Many definitive hosts have been documented for D. insignis; however, the life cycle has been studied only in laboratories, and only a single phylogenetic study has been conducted on D. insignis (from Canada). The goals of the present study were to investigate the prevalence of infections with Dracunculus species among wildlife at a single site (Di-Lane plantation) in the southeastern United States, evaluate the genetic diversity of parasites at this site, and investigate potential paratenic hosts that may be involved in transmission. Over 3 yr, we sampled 228 meso-mammals, reporting an overall prevalence of infection with Dracunculus insignis of 20% (46/228). Amphibians and fish were sampled in the same geographic area as infected meso-mammals. Dracunculus insignis third-stage larvae were recovered from 2 different species of amphibians, but all fish sampled were negative. Phylogenetic analysis of the partial cytochrome c oxidase I (COI) gene showed very little diversity of Dracunculus at Di-Lane; however, we did recover a single nematode from a Virginia opossum (Didelphis virginiana) that falls outside of the D. insignis clade, more closely aligns with Dracunculus lutrae, and may represent an undescribed species. This work documents the occurrence of D. insignis in frogs, a potential transmission pathway for D. insignis at a single geographic site in nature. When applied to the global Guinea Worm Eradication Program, and Chad, Africa, in particular, this work increases our knowledge of the potential role of aquatic animals in the transmission of Dracunculus species and informs on potential intervention strategies that may be applied to the eradication of Guinea worm in Africa.
Subject(s)
Animals, Wild/parasitology , Dracunculiasis/veterinary , Dracunculus Nematode/classification , Mammals/parasitology , Amphibians/parasitology , Animals , Armadillos/parasitology , Chad , Coyotes/parasitology , Dracunculiasis/epidemiology , Dracunculiasis/prevention & control , Dracunculiasis/transmission , Dracunculus Nematode/genetics , Dracunculus Nematode/growth & development , Dracunculus Nematode/isolation & purification , Female , Fishes/parasitology , Genetic Variation , Georgia/epidemiology , Life Cycle Stages , Male , Opossums/parasitology , Phylogeny , Ponds , Prevalence , Raccoons/parasitologyABSTRACT
Few human infectious diseases have been driven as close to eradication as dracunculiasis, caused by the Guinea worm parasite (Dracunculus medinensis). The number of human cases of Guinea worm decreased from an estimated 3.5 million in 1986 to mere hundreds by the 2010s. In Chad, domestic dogs were diagnosed with Guinea worm for the first time in 2012, and the numbers of infected dogs have increased annually. The presence of the parasite in a non-human host now challenges efforts to eradicate D. medinensis, making it critical to understand the factors that correlate with infection in dogs. In this study, we evaluated anthropogenic and environmental factors most predictive of detection of D. medinensis infection in domestic dog populations in Chad. Using boosted regression tree models to identify covariates of importance for predicting D. medinensis infection at the village and spatial hotspot levels, while controlling for surveillance intensity, we found that the presence of infection in a village was predicted by a combination of demographic (e.g. fishing village identity, dog population size), geographic (e.g. local variation in elevation), and climatic (e.g. precipitation and temperature) factors, which differed between northern and southern villages. In contrast, the presence of a village in a spatial infection hotspot, was primarily predicted by geography and climate. Our findings suggest that factors intrinsic to individual villages are highly predictive of the detection of Guinea worm parasite presence, whereas village membership in a spatial infection hotspot is largely determined by location and climate. This study provides new insight into the landscape-scale epidemiology of a debilitating parasite and can be used to more effectively target ongoing research and possibly eradication and control efforts.
Subject(s)
Dog Diseases/epidemiology , Dracunculiasis/epidemiology , Dracunculiasis/veterinary , Animals , Chad/epidemiology , Climate , Disease Eradication/statistics & numerical data , Dog Diseases/parasitology , Dogs , Dracunculiasis/transmission , Dracunculus Nematode/isolation & purification , Geography , Machine LearningABSTRACT
Guinea worm Dracunculus medinensis causes debilitating disease in people and is subject to an ongoing global eradication programme. Research and controls are constrained by a lack of diagnostic tools. We developed a specific and sensitive LAMP method for detecting D. medinensis larval DNA in copepod vectors. We were able to detect a single larva in a background of field-collected copepods. This method could form the basis of a "pond-side test" for detecting potential sources of Guinea worm infection in the environment, in copepods, including in the guts of fish as potential transport hosts, enabling research, surveillance and targeting of control measures. The key constraint on the utility of this assay as a field diagnostic, is a lack of knowledge of variation in the temporal and spatial distribution of D. medinensis larvae in copepods in water bodies in the affected areas and how best to sample copepods to obtain a reliable diagnostic sample. These fundamental knowledge gaps could readily be addressed with field collections of samples across areas experiencing a range of worm infection frequencies, coupled with field and laboratory analyses using LAMP and PCR.
Subject(s)
Copepoda/parasitology , Dracunculus Nematode/isolation & purification , Molecular Diagnostic Techniques/standards , Nucleic Acid Amplification Techniques/standards , Ponds/parasitology , Africa , Animals , Base Sequence , Cats , Copepoda/genetics , DNA Primers/chemistry , DNA, Helminth/isolation & purification , Disease Vectors , Dogs , Dracunculus Nematode/genetics , Humans , Papio , Sensitivity and Specificity , Time FactorsABSTRACT
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.
Subject(s)
Dog Diseases/epidemiology , Dracunculiasis/veterinary , Dracunculus Nematode/isolation & purification , Animals , Chad/epidemiology , Dog Diseases/parasitology , Dogs , Dracunculiasis/epidemiology , Dracunculiasis/parasitology , Dracunculus Nematode/classification , Dracunculus Nematode/genetics , Epidemiological Monitoring , Female , Humans , MaleABSTRACT
Dracunculiasis or guinea-worm infection is a water-borne, parasitic disease that can cause major morbidity. Dracunculiasis in patients with diabetes can be misdiagnosed as a diabetic foot abscess, which is a common complication of poorly controlled diabetes. This is a report of guinea-worm disease (GWD) in a 57-year-old man with diabetes from a rural area of Kerala. There is need for awareness among physicians about the occurrence of GWD in people with diabetes and the need to ensure supply of safe drinking water to prevent its re- emergence. Though WHO has declared India free of GWD, a few cases have been reported from the country.
Subject(s)
Abscess/diagnosis , Diabetes Mellitus, Type 2/complications , Diabetic Foot/diagnosis , Dracunculiasis/diagnosis , Dracunculus Nematode/isolation & purification , Abscess/parasitology , Animals , Diabetic Foot/etiology , Diagnosis, Differential , Dracunculiasis/parasitology , Drinking Water/parasitology , Foot , Humans , India , Male , Middle AgedSubject(s)
Disease Eradication/trends , Dog Diseases/epidemiology , Dracunculiasis/epidemiology , Dracunculiasis/parasitology , Dracunculus Nematode/isolation & purification , Dracunculus Nematode/pathogenicity , Zoonoses/epidemiology , Animals , Chad/epidemiology , Dog Diseases/parasitology , Dog Diseases/transmission , Dogs , Dracunculiasis/transmission , Dracunculiasis/veterinary , Goals , Humans , Population Surveillance , Time Factors , World Health Organization/organization & administration , Zoonoses/parasitology , Zoonoses/prevention & control , Zoonoses/transmissionABSTRACT
Dracunculus medinensis, or human Guinea worm (GW), causes a painful and debilitating infection. The global Guinea Worm Eradication Program (GWEP) has successfully reduced human GW cases from 3.5 million in 21 countries in 1986 to only 30 cases in three remaining countries in 2017. Since 2012, an increase in GW infections in domestic dogs, cats and baboons has been reported. Because these infections have not followed classical GW epidemiological patterns resulting from water-borne transmission, it has been hypothesized that transmission occurs via a paratenic host. Thus, we investigated the potential of aquatic animals to serve as paratenic hosts for D. medinensis in Chad, Africa. During three rainy and two dry season trips we detected no GW larvae in 234 fish, two reptiles and two turtles; however, seven GW larvae were recovered from 4 (1.4%) of 276 adult frogs. These data suggest GW infections may occur from ingestion of frogs but the importance of this route is unknown. Additional studies are needed, especially for other possible routes (e.g., ingestion of fish intestines that were recently shown to be a risk). Significantly, 150 years after the life cycle of D. medinensis was described, our data highlights important gaps in the knowledge of GW ecology.
Subject(s)
Animal Diseases/parasitology , Aquatic Organisms/parasitology , Dracunculus Nematode/isolation & purification , Animals , Anura , Chad/epidemiology , Humans , Larva , Public Health SurveillanceABSTRACT
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.
Subject(s)
Disease Transmission, Infectious , Dracunculiasis/parasitology , Dracunculiasis/veterinary , Dracunculus Nematode/classification , Dracunculus Nematode/genetics , Genetic Variation , Genetics, Population , Animals , Chad , DNA, Mitochondrial/genetics , Dogs , Dracunculiasis/transmission , Dracunculus Nematode/isolation & purification , Ethiopia , Female , Genotype , Genotyping Techniques , Humans , Mali , Microsatellite Repeats , Papio , SudanABSTRACT
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.
Subject(s)
Disease Eradication/statistics & numerical data , Dogs/parasitology , Dracunculiasis/prevention & control , Global Health , Animals , Chad/epidemiology , Dracunculiasis/epidemiology , Dracunculiasis/transmission , Dracunculus Nematode/genetics , Dracunculus Nematode/isolation & purification , Epidemiological Monitoring , Ethiopia/epidemiology , Female , Humans , Male , Water SupplyABSTRACT
We reviewed 62 new cases and 18 published reports of Dracunculus infections in domestic dogs and cats to describe the epidemiology of this parasite in dogs and cats in North America. We collected host and parasite data when available, including age, sex, and breed of dog, nematode location in the host, and any clinical signs at presentation and/or description of the apparent lesion. For dogs, infections were noted in six of the AKC breed groups, but none was reported from the toy group or the miscellaneous breed class. Age of infected dogs ranged from 7â¯months to 19â¯years (median 4â¯years; average 5.3â¯years), and infection rates were similar in male and female dogs. Most nematodes were associated with the distal extremities, but worms were also found in the chest/thorax, abdomen, head, and flank. Although most infected dogs had a single worm, three dogs had two or more worms that were collected from multiple lesions. Three new cat cases, with similar lesions, presentations and seasonality, were detected in Alabama, North Carolina and Texas. Cases were reported from a wide geographic range throughout eastern North America, during every month of the year, but 72% of infections were diagnosed in the late winter to early spring (December to May). All collected worms were larvigerous females which cannot be identified to species based on morphologic characters. Thus, we attempted to amplify and sequence a portion of the cytochrome c oxidase subunit I (COI) gene for specific identification. Although 13 worms from 12 cases were available, sequences were obtained for only eight worms from seven cases. These eight worms were D. insignis, a common parasite of raccoons (Procyon lotor) and other primarily carnivorous mammals. Female worms are the most likely to be detected in dogs and cats because male worms do not emerge, parasites should be preserved in ethanol for molecular identification. Although this study used convenience sampling of available data, we found that the parasite is widespread throughout the eastern US and Canada and that Dracunculus infections in dogs are more common than is revealed in published literature. However, more research is needed to understand the epidemiology, including transmission route(s), prevalence, and distribution of this parasite.
Subject(s)
Cat Diseases/epidemiology , Cats/parasitology , Dog Diseases/epidemiology , Dogs/parasitology , Dracunculiasis/veterinary , Alabama , Animals , Canada , Cat Diseases/parasitology , Dog Diseases/parasitology , Dracunculiasis/epidemiology , Dracunculus Nematode/isolation & purification , Dracunculus Nematode/pathogenicity , Female , Male , North America/epidemiology , North Carolina , TexasABSTRACT
BACKGROUND: Of the three diseases targeted for eradication by WHO, two are so-called Neglected Tropical Diseases (NTDs)-guinea worm disease (GWD) and yaws. The Guinea Worm Eradication Programme (GWEP) is in its final stages, with only 25 reported in 2016. However, global eradication still requires certification by WHO of the absence of transmission in all countries. We analyze the cost-effectiveness of the GWEP in the end game, when the number of cases is lower and the cost per case is higher than at any other time. Ours is the first economic evaluation of the GWEP since a World Bank study in 1997. METHODS: Using data from the GWEP, we estimate the cost of the implementation, pre-certification and certification stages. We model cost-effectiveness in the period 1986-2030. We compare the GWEP to two alternative scenarios: doing nothing (no intervention since 1986) and control (only surveillance and outbreak response during 2016-2030). We report the cost per case averted, cost per disability adjusted life year (DALY) averted and cost per at-risk life year averted. We assess cost-effectiveness against a threshold of about one half GDP per capita (less than US$ 500 in low income countries). All costs are expressed in US$ of 2015. RESULTS: The GWEP cost an estimated US$ 11 (95% uncertainty interval, 4.70-12.49) per case averted in the period 1986-2030. The pre-certification and certification phases can cost as much as US$ 0.0041 and US$ 0.0015 per capita per year. The cost per DALY averted by the GWEP relative to doing nothing is estimated at US$ 222 (118-372) in 1986-2030. The GWEP is probably more cost-effective than control by the year 2030. The GWEP is certainly more cost-effective than control if willingness to pay for one year of life lived without the risk of GWD exceeds US$ 0.10. DISCUSSION: Even if economic costs are two times as high as the financial costs estimated for the period to 2020, the GWEP will still be cost-effective relative to doing nothing. Whether the GWEP turns out to be the most cost-effective alternative in the period beyond 2015 depends on the time horizon. When framed in terms of the number of years of life lived without the risk of GWD, a case can be made more easily for finishing the end game, including certification of the absence of transmission.
Subject(s)
Disease Eradication/economics , Dracunculiasis/prevention & control , Neglected Diseases/prevention & control , Animals , Cost-Benefit Analysis , Disease Eradication/legislation & jurisprudence , Dracunculiasis/drug therapy , Dracunculiasis/epidemiology , Dracunculiasis/parasitology , Dracunculus Nematode/isolation & purification , Humans , Neglected Diseases/drug therapy , Neglected Diseases/epidemiology , Neglected Diseases/parasitologyABSTRACT
Introducción: Dracunculus medinensis o gusano de Guinea es el mayor nematodo parásito del hombre y causa unas úlceras que generan una importante incapacidad durante 2-4 meses, generalmente, que coincide con los periodos de siembra o recogida de las cosechas. Por ello, esta enfermedad, denominada dracunculosis, provoca importantes pérdidas económicas. En sociedades pobres, las más afectadas, estas pérdidas las mantienen en un círculo vicioso de pobreza del que no pueden salir sin ayuda. La dracunculosis forma parte del grupo de enfermedades tropicales olvidadas que, según la OMS, afecta a más de 1000 millones de pobres del mundo. Objetivo: Dar a conocer a la sociedad científica hispanohablante el estado actual de la enfermedad y de su lucha contra ella. Material y métodos: Se ha llevado a cabo una búsqueda bibliográfica en bases de datos científicas, especialmente PubMed (Medline) de la Biblioteca Nacional de Medicina (NML) de Estados Unidos, y se han revisado los informes publicados por los principales organismos e instituciones implicados en la lucha contra la dracunculosis, especialmente The Carter Center, la Organización Mundial de la Salud y Centers for Disease Control and Prevention (CDC) de EE.UU. Resultados: En 1986 se inició una campaña de erradicación basada en las características epidemiológicas de la enfermedad y en la implicación de los países endémicos, lo que permitía plantear ese objetivo, aprobado por la Asamblea Mundial de la Salud en 1981. Este parásito se distribuía por 18 países de África y 3 de Asia, afectando a 5-10 millones de pobres, según la OMS. El esfuerzo solidario de instituciones, fundaciones, empresas y personal, sobre todo voluntario, ha permitido reducir el número de casos en más del 99,99% tras 30 años de campaña. En 2015 se han contabilizado sólo 22 casos limitados a 4 países de África: Malí, Etiopía, Sudán del Sur y Chad. En 2016 se han detectado 25 casos: 16 en Chad, 3 en Etiopía, 6 en Sudán del Sur y ninguno en Malí (datos provisionales1). Conclusión: Se trabaja con la esperanza de que en 2020 la enfermedad esté erradicada del planeta, siendo así la primera de un parásito, mostrándose además que el trabajo de educación sanitaria de la población afectada ha resultado vital para el éxito de la campaña de erradicación
Introduction: Dracunculus medinensis or Guinea worm is the largest nematode parasite in man and causes ulcers that generate a major disability generally for 2-4 months, coinciding with the periods of planting or harvesting of the crops. Therefore, this disease, denominated dracunculiasis, causes important economic losses. In poor societies, those most affected, these losses keep them in a vicious circle of poverty from which they can not leave without help. Dracunculiasis is one of a group of Neglected Tropical Diseases that, according to the WHO, affects more than 1 billion poor people in the world. Objective: Introduce to the Spanish-speaking scientific community about the current status of the dracunculiasis and its fight against it. Material and methods: A bibliographic search has been carried out in scientific databases, especially PubMed (Medline) of the National Library of Medicine (NML) of the United States, and the reports published by the main organisms and institutions involved in the fight against dracunculiasis have been reviewed, especially those of The Carter Center, the World Health Organization and Centers for Disease Control and Prevention (CDC). Results: An eradication campaign was initiated in 1986, based on the epidemiological characteristics of the disease and the involvement of endemic countries, which allowed to raise that objective, adopted by the World Health Assembly in 1981. This parasite was occurring in 18 countries of Africa and 3 of Asia, affecting 5-10 million poor people, according to WHO. The solidarity effort of institutions, foundations, companies and people, especially volunteers, has allowed to reduce the number of cases in more than 99.99% after 30 years of campaign. In 2015, only 22 cases limited to 4 African countries were recorded: Mali, Ethiopia, South Sudan and Chad. In 2016, 25 cases have been detected: 16 in Chad, 3 in Ethiopia, 6 in South Sudan and none in Mali (provisional data1). Conclusion: It works in the hope that in 2020 the disease will be eradicated from the planet, thus being the first of a parasite. This fight also shows that the health education work on the affected population, carried out jointly by volunteers and officials, is vital to the success of this eradication campaign
Subject(s)
Humans , Male , Female , Dracunculiasis/drug therapy , Dracunculiasis/epidemiology , Dracunculus Nematode , Dracunculus Nematode/isolation & purification , Health Education/methods , Health Education/trends , Disease Eradication/methods , Disease Eradication/trends , Poverty/trends , Life Cycle Stages , Volunteers/statistics & numerical data , Disease Eradication/statistics & numerical data , Communicable Disease Control/methodsSubject(s)
Disease Eradication/statistics & numerical data , Disease Eradication/trends , Dracunculiasis/epidemiology , Dracunculiasis/parasitology , Dracunculus Nematode , Animals , Disease Eradication/economics , Dog Diseases/epidemiology , Dog Diseases/parasitology , Dogs , Dracunculiasis/prevention & control , Dracunculiasis/transmission , Dracunculus Nematode/isolation & purification , Drinking Water/parasitology , Drinking Water/standards , Female , Ghana/epidemiology , Goals , Malaria/epidemiology , Malaria/parasitology , Malaria/prevention & control , Malaria/transmission , Male , Mosquito Control/methods , Poliomyelitis/epidemiology , Time FactorsSubject(s)
Dog Diseases/epidemiology , Dog Diseases/transmission , Dracunculiasis/epidemiology , Dracunculiasis/veterinary , Dracunculus Nematode/isolation & purification , Zoonoses/epidemiology , Zoonoses/transmission , Animals , Chad/epidemiology , Disease Eradication , Dog Diseases/parasitology , Dog Diseases/prevention & control , Dogs , Dracunculiasis/prevention & control , Dracunculiasis/transmission , Drinking Water/parasitology , Drinking Water/standards , Humans , Rivers/parasitology , Zoonoses/parasitology , Zoonoses/prevention & controlABSTRACT
BACKGROUND: Despite being certified guinea worm free in 2007, Cameroon continues surveillance efforts to ensure rapid verification of any suspected reoccurrence. This includes the investigation of every rumor and confirmation of each suspicious expulsed worm. This paper presents fieldwork carried out to investigate a guinea worm rumor in Cameroon which turned out to be an Onchocerca volvulus mimicking Dracunculus medinensis. METHODS: The investigation included a field visit to the subsistence farming community where the rumor was reported. During the visit, interviews were conducted with health staff who managed the case and the elderly farmer from whom the worm was retrieved. An investigation of any potential missed guinea worm cases was also conducted through interviews with community residents and reviews of the health facility's medical records. This was combined with laboratory analyses of water samples from the community's water sources and the retrieved worm which was removed from the patient via wrapping it around a stick. RESULTS: Microscopy and molecular analyses of the retrieved worm revealed a female Onchocerca volvulus whose expulsion strongly mimicked guinea worm. In addition to presenting findings of our investigation, this paper discusses distinguishing elements between the two parasites and gives an overview of guinea worm eradication efforts in Cameroon as well as current challenges to the worm's eradication globally. CONCLUSIONS: The investigation findings suggest the evolving Onchocerca volvulus worm tropisms' adaptive survival behavior worth further investigation. Strategies used to successfully control guinea worm in Cameroon could be adapted for Onchocerca volvulus control.