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1.
Lancet Microbe ; 3(2): e105-e112, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35544041

RESUMO

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.


Assuntos
Dracunculíase , Dracunculus , Animais , Chade/epidemiologia , Estudos Transversais , Surtos de Doenças/veterinária , Cães , Dracunculíase/epidemiologia , Dracunculus/genética , Feminino , Humanos
3.
Curr Biol ; 32(4): R170-R173, 2022 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-35231412

RESUMO

Domestic dogs have an important role in the ecology of transmission of the Guinea worm, a debilitating human parasite. A new study documents how fish content in dogs' diets can predict Guinea worm infection status, suggesting additional avenues for control.


Assuntos
Doenças Transmissíveis , Doenças do Cão , Dracunculíase , Animais , Dieta/veterinária , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Dracunculíase/parasitologia , Dracunculíase/prevenção & controle , Dracunculíase/transmissão , Dracunculus , Humanos
4.
Am J Trop Med Hyg ; 106(3): 818-822, 2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-35073509

RESUMO

Dracunculus medinensis, also known as the African Guinea worm, is the causative agent of dracunculiasis and the focus of the global Guinea Worm Eradication Program (GWEP). Transmission of D. medinensis to humans occurs primarily by drinking water containing cyclopoid copepods infected with third-stage D. medinensis larvae. A common intervention to interrupt transmission and decrease the number of copepods in infected water bodies is the application of the organophosphate larvicide Abate® (temephos). However, the use of alternative compounds to help decrease copepod populations would be beneficial to the GWEP. We compared the immobilization of copepods by three compounds: Abate, Natular® (spinosad), and diflubenzuron. Our results confirm that neither diflubenzuron nor Natular immobilized copepods as quickly or as effectively as Abate. However, doubling or tripling the suggested concentration of Natular resulted in immobilization rates similar to Abate over 72 hours of continuous exposure. Further research on the possible effects of higher concentrations of Natular on the environment and nontarget organisms is necessary to determine whether this compound can be used safely to control the copepod population.


Assuntos
Copépodes , Diflubenzuron , Dracunculíase , Animais , Dracunculíase/epidemiologia , Dracunculus , Combinação de Medicamentos , Humanos , Macrolídeos , Temefós
5.
Curr Biol ; 32(4): 775-782.e4, 2022 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-34910949

RESUMO

Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis, particularly in domestic dogs Canis familiaris, has become the major impediment to global eradication of this human disease. 93% of all Guinea worms detected worldwide in 2020 were in dogs in Chad. Novel, non-classical pathways for transmission of Guinea worm in dogs, involving consumption of fish, have been hypothesized to support the maintenance of this animal reservoir. We quantified and analyzed variation in Guinea worm emergence in dogs in Chad, across three climatic seasons, in multiple villages and districts. We applied forensic stable isotope analyses to quantify dietary variation within and among dogs and GPS tracking to characterize their spatial ecology. At the end of the hot-dry season and beginning of the wet season, when fishing by people is most intensive, Guinea worm emergence rates in dogs were highest, dogs ate most fish, and fish consumption was most closely associated with disease. Consumption of fish by dogs enables a non-classical transmission pathway for Guinea worm in Chad. Seasonal fisheries and the facilitation of dogs eating fish are likely contributing to disease persistence and to this key impediment to human disease eradication. Interrelated natural resource use, climatic variation, companion animal ecology, and human health highlight the indispensability of One Health approaches to the challenges of eradicating Guinea worm and other zoonotic diseases.


Assuntos
Dracunculíase , Dracunculus , Animais , Cães , Dracunculíase/epidemiologia , Dracunculíase/prevenção & controle , Dracunculíase/veterinária , Pesqueiros , Humanos , Estações do Ano , Zoonoses
6.
PLoS Negl Trop Dis ; 15(8): e0009675, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34370746

RESUMO

BACKGROUND: In the absence of a vaccine or pharmacological treatment, prevention and control of Guinea worm disease is dependent on timely identification and containment of cases to interrupt transmission. The Chad Guinea Worm Eradication Program (CGWEP) surveillance system detects and monitors Guinea worm disease in both humans and animals. Although Guinea worm cases in humans has declined, the discovery of canine infections in dogs in Chad has posed a significant challenge to eradication efforts. A foundational information system that supports the surveillance activities with modern data management practices is needed to support continued program efficacy. METHODS: We sought to assess the current CGWEP surveillance and information system to identify gaps and redundancies and propose system improvements. We reviewed documentation, consulted with subject matter experts and stakeholders, inventoried datasets to map data elements and information flow, and mapped data management processes. We used the Information Value Cycle (IVC) and Data-Information System-Context (DISC) frameworks to help understand the information generated and identify gaps. RESULTS: Findings from this study identified areas for improvement, including the need for consolidation of forms that capture the same demographic variables, which could be accomplished with an electronic data capture system. Further, the mental models (conceptual frameworks) IVC and DISC highlighted the need for more detailed, standardized workflows specifically related to information management. CONCLUSIONS: Based on these findings, we proposed a four-phased roadmap for centralizing data systems and transitioning to an electronic data capture system. These included: development of a data governance plan, transition to electronic data entry and centralized data storage, transition to a relational database, and cloud-based integration. The method and outcome of this assessment could be used by other neglected tropical disease programs looking to transition to modern electronic data capture systems.


Assuntos
Doenças do Cão/prevenção & controle , Dracunculíase/veterinária , Dracunculus/fisiologia , Animais , Chade/epidemiologia , Erradicação de Doenças , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Cães , Dracunculíase/epidemiologia , Dracunculíase/parasitologia , Dracunculíase/prevenção & controle , Dracunculus/genética
7.
BMJ Open ; 11(8): e049732, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34353803

RESUMO

OBJECTIVES: To quantify conflict events and access across countries that remain to be certified free of transmission of Dracunculus medinensis (Guinea worm disease) or require postcertification surveillance as part of the Guinea Worm Eradication Programme (GWEP). SETTING AND PARTICIPANTS: Populations living in Guinea worm affected areas across seven precertification countries and 13 postcertification sub-Saharan African countries. OUTCOME MEASURES: The number of conflict events and rates per 100 000 population, the main types of conflict and actors reported to be responsible for events were summarised and mapped across all countries. Chad and Mali were presented as case studies. Guinea worm information was based on GWEP reports. Conflict data were obtained from the Armed Conflict Location and Event Data Project. Maps were created using ArcGIS V.10.7 and access was measured as regional distance and time to cities. RESULTS: More than 980 000 conflict events were reported between 2000 and 2020, with a significant increase since 2018. The highest number and rates were reported in precertification Mali (n=2556; 13.0 per 100 000), South Sudan (n=2143; 19.4), Democratic Republic of Congo (n=7016; 8.1) and postcertification Nigeria (n=6903; 3.4), Central Africa Republic (n=1251; 26.4), Burkina Faso (n=2004; 9.7). Violence against civilians, protests and battles were most frequently reported with several different actors involved including Unidentified Armed Groups and Boko Haram. Chad and Mali had contracting epidemiological and conflict situations with affected regions up to 700 km from the capital or 10 hours to the nearest city. CONCLUSIONS: Understanding the spatial-temporal patterns of conflict events, identifying hotspots, the actors responsible and their sphere of influence is critical for the GWEP and other public health programmes to develop practical risk assessments, deliver essential health interventions, implement innovative surveillance, determine certification and meet the goals of eradication.


Assuntos
Dracunculíase , Dracunculus , Animais , Burkina Faso , Certificação , Dracunculíase/epidemiologia , Dracunculíase/prevenção & controle , Humanos , Mali/epidemiologia
8.
Int J Parasitol ; 51(12): 1027-1034, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34246634

RESUMO

Guinea worm (Dracunculus medinensis) has exerted a high human health burden in parts of Africa. Complete eradication of Guinea worm disease (dracunculiasis) may be delayed by the circulation of the parasite in domestic dogs. As with humans, dogs acquire the parasite by directly ingesting infected copepods, and recent evidence suggests that consuming frogs that ingested infected copepods as tadpoles may be a viable transmission route (paratenic route). To understand the relative contributions of direct and paratenic transmission routes, we developed a mathematical model that describes transmission of Guinea worm between dogs, copepods and frogs. We explored how the parasite basic reproductive number (R0) depends on parameters amenable to actionable interventions under three scenarios: frogs/tadpoles do not consume copepods; tadpoles consume copepods but frogs do not contribute to transmission; and frogs are paratenic hosts. We found a non-monotonic relationship between the number of dogs and R0. Generally, frogs can contribute to disease control by removing infected copepods from the waterbody even when paratenic transmission can occur. However, paratenic transmission could play an important role in maintaining the parasite when direct transmission is reduced by interventions focused on reducing copepod ingestion by dogs. Together, these suggest that the most effective intervention strategies may be those which focus on the reduction of copepods, as this reduces outbreak potential irrespective of the importance of the paratenic route.


Assuntos
Copépodes , Dracunculíase , Animais , Anuros , Surtos de Doenças , Cães , Dracunculíase/epidemiologia , Dracunculíase/prevenção & controle , Dracunculíase/veterinária , Dracunculus
9.
PLoS Negl Trop Dis ; 15(7): e0009609, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34310598

RESUMO

BACKGROUND: Guinea worm (Dracunculus medinensis) was detected in Chad in 2010 after a supposed ten-year absence, posing a challenge to the global eradication effort. Initiation of a village-based surveillance system in 2012 revealed a substantial number of dogs infected with Guinea worm, raising questions about paratenic hosts and cross-species transmission. METHODOLOGY/PRINCIPAL FINDINGS: We coupled genomic and surveillance case data from 2012-2018 to investigate the modes of transmission between dog and human hosts and the geographic connectivity of worms. Eighty-six variants across four genes in the mitochondrial genome identified 41 genetically distinct worm genotypes. Spatiotemporal modeling revealed worms with the same genotype ('genetically identical') were within a median range of 18.6 kilometers of each other, but largely within approximately 50 kilometers. Genetically identical worms varied in their degree of spatial clustering, suggesting there may be different factors that favor or constrain transmission. Each worm was surrounded by five to ten genetically distinct worms within a 50 kilometer radius. As expected, we observed a change in the genetic similarity distribution between pairs of worms using variants across the complete mitochondrial genome in an independent population. CONCLUSIONS/SIGNIFICANCE: In the largest study linking genetic and surveillance data to date of Guinea worm cases in Chad, we show genetic identity and modeling can facilitate the understanding of local transmission. The co-occurrence of genetically non-identical worms in quantitatively identified transmission ranges highlights the necessity for genomic tools to link cases. The improved discrimination between pairs of worms from variants identified across the complete mitochondrial genome suggests that expanding the number of genomic markers could link cases at a finer scale. These results suggest that scaling up genomic surveillance for Guinea worm may provide additional value for programmatic decision-making critical for monitoring cases and intervention efficacy to achieve elimination.


Assuntos
Dracunculíase/epidemiologia , Dracunculus/genética , Vigilância da População/métodos , Animais , Chade/epidemiologia , DNA de Helmintos/genética , Marcadores Genéticos , Genoma Helmíntico , Genoma Mitocondrial , Humanos
10.
Sci Rep ; 11(1): 11802, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34083638

RESUMO

Dracunculus spp. are parasitic nematodes that infect numerous species of mammals and reptiles. The life cycles of Dracunculus species are complex, and unknowns remain regarding the role of paratenic and transport hosts in transmission to definitive hosts. We had two primary objectives: to assess the susceptibility of several species of anurans, lizards, and fish as paratenic hosts for Dracunculus species, and to determine the long-term persistence of Dracunculus infections in African clawed frogs (Xenopus laevis). Animals were orally exposed to copepods infected with infectious third-stage larvae (L3s) of either Dracunculus insignis or D. medinensis. Dracunculus L3s were recovered from four anuran species, two lizard species, and one fish species, demonstrating that Dracunculus can infect tissues of a diversity of species. In long-term persistence trials, D. medinensis L3s were recovered from African clawed frogs tissues up to 58 days post-infection, and D. insignis L3s were recovered up to 244 days post-infection. Our findings regarding the susceptibility of novel species of frogs, lizards, and fish to infection with Dracunculus nematodes, and long-term persistence of L3s in paratenic hosts, address pressing knowledge gaps regarding Dracunculus infection in paratenic hosts and may guide future research regarding the transmission of Dracunculus to definitive mammalian hosts.


Assuntos
Doenças dos Animais/parasitologia , Anuros , Dracunculíase/veterinária , Dracunculus , Peixes , Interações Hospedeiro-Parasita , Lagartos , Animais , Larva
11.
Am J Trop Med Hyg ; 105(1): 188-195, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34029207

RESUMO

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.


Assuntos
Erradicação de Doenças/estatística & dados numéricos , Erradicação de Doenças/tendências , Dracunculíase/epidemiologia , Dracunculíase/fisiopatologia , Dracunculus/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Chade/epidemiologia , Métodos Epidemiológicos , Feminino , Previsões , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Adulto Jovem
13.
PLoS Negl Trop Dis ; 15(3): e0009285, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33735242

RESUMO

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.


Assuntos
Doenças do Cão/epidemiologia , Dracunculíase/epidemiologia , Dracunculíase/veterinária , Conhecimentos, Atitudes e Prática em Saúde , Prevenção Primária/métodos , Adulto , Animais , Chade/epidemiologia , Doenças do Cão/parasitologia , Cães , Dracunculus/isolamento & purificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Prevenção Primária/educação , Inquéritos e Questionários
14.
Int J Infect Dis ; 105: 739-742, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33737138

RESUMO

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.


Assuntos
Dracunculíase/diagnóstico , Dracunculus/classificação , Dracunculus/genética , Animais , Anti-Helmínticos/uso terapêutico , Dracunculíase/tratamento farmacológico , Dracunculíase/parasitologia , Dracunculus/isolamento & purificação , Humanos , Larva/classificação , Larva/genética , Masculino , Vigilância em Saúde Pública , Tiabendazol/uso terapêutico , Resultado do Tratamento , Vietnã , Doenças Transmitidas pela Água/diagnóstico , Adulto Jovem
15.
J Theor Biol ; 521: 110683, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-33744311

RESUMO

Guinea-worm disease (GWD) was thought to be almost eliminated in Chad when it reemerged in 2010. The disease now shows a peculiar pattern of spreading along Chari River and its tributaries, rather than clustering around a particular drinking water source. We create a mathematical model of GWD that includes the population dynamics of the parasite as well as the dynamics of its hosts (copepods, fish, humans, and domestic dogs). We calibrate our model based on data from the literature and validate it on the recent GWD annual incidence data from Chad. The effective reproduction number predicted by our model agrees well with the empirical value of roughly 1.25 derived directly from the data. Our model thus supports the hypothesis that the parasite now uses fish as intermediate transport hosts. We predict that GWD transmission can be most easily interrupted by avoiding eating uncooked fish and by burying the fish entrails to prevent transmission through dogs. Increasing the mortality of copepods and even partially containing infected dogs to limit their access to water sources is another important factor for GWD eradication.


Assuntos
Dracunculíase , Animais , Chade/epidemiologia , Erradicação de Doenças , Cães , Dracunculíase/epidemiologia , Dracunculíase/prevenção & controle , Dracunculíase/veterinária , Dracunculus , Modelos Teóricos
17.
Am J Trop Med Hyg ; 104(4): 1418-1424, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33617473

RESUMO

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.


Assuntos
Animais Domésticos/parasitologia , Doenças do Cão/parasitologia , Cães/parasitologia , Dracunculíase/veterinária , Dracunculus/isolamento & purificação , Carga Parasitária/métodos , Animais , Chade/epidemiologia , Doenças do Cão/epidemiologia , Dracunculíase/epidemiologia , Características da Família , Feminino , Masculino , Carga Parasitária/estatística & dados numéricos , Análise de Regressão , Fatores de Risco
19.
Parasitol Res ; 120(4): 1371-1377, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33624148

RESUMO

We report and discuss the surprising encounter of a dog naturally infected by Dracunculus sp. in Brazil, a brief clinical history of the animal and a procedure for removing the nematode. We also present details on the morphology of the fragments collected from the nematode and a phylogenetic comparison of the partial sequences of the mitochondrial 18S rRNA and cytochrome c oxidase subunit I (COI) genes, deposited with others in GenBank. The samples were an independent lineage forming a well-supported monophyletic assemblage with D. medinensis. We thus conclude that this species has not yet been sequenced or even described and will only be elucidated by more information because only two species of Dracunculus have been reported in Brazil, D. fuelleborni and D. brasiliensis.


Assuntos
Doenças do Cão/parasitologia , Dracunculíase/veterinária , Dracunculus/genética , Animais , Brasil , Cães , Dracunculíase/parasitologia , Dracunculus/anatomia & histologia , Dracunculus/classificação , Genes de Helmintos , Genes de RNAr , Masculino , Filogenia , RNA de Helmintos/genética , RNA Mitocondrial/genética , RNA Ribossômico 18S/genética
20.
PLoS Negl Trop Dis ; 15(1): e0009082, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33507903

RESUMO

INTRODUCTION: A number of neglected tropical diseases are targeted for elimination or eradication. An effective surveillance system is critical to determine if these goals have been achieved and maintained. Trachoma has two related but morphologically different presentations that are monitored for elimination, the active infectious form of trachoma and trachomatous trichiasis (TT), the progression of the disease. There are a number of lessons learnt from the Guinea worm surveillance system that are particularly compatible for TT surveillance and the onchocerciasis surveillance system which can provide insights for surveillance of the infectious form of trachoma. METHODS/PRINCIPAL FINDINGS: A literature search of peer-reviewed published papers and grey literature was conducted using PUBMED and Google Scholar for articles relating to dracunculiasis or Guinea worm, onchocerciasis and trachoma, along with surveillance or elimination or eradication. The abstracts of relevant papers were read and inclusion was determined based on specified inclusion and exclusion criteria. The credibility and bias of relevant papers were also critically assessed using published criteria. A total of 41 papers were identified that were eligible for inclusion into the review. The Guinea worm programme is designed around a surveillance-containment strategy and combines both active and passive surveillance approaches, with a focus on village-based surveillance and reporting. Although rumour reporting and a monetary incentive for the identification of confirmed Guinea worm cases have been reported as successful for identifying previously unknown transmission there is little unbiased evidence to support this conclusion. More rigorous evidence through a randomised controlled trial, influenced by motivational factors identified through formative research, would be necessary in order to consider applicability for TT case finding in an elimination setting. The onchocerciasis surveillance strategy focuses on active surveillance through sentinel surveillance of villages and breeding sites. It relies on an entomological component, monitoring infectivity rates of black flies and an epidemiological component, tracking exposure to infection in humans. Challenges have included the introduction of relatively complex diagnostics that are not readily available in onchocerciasis endemic countries and target thresholds, which are practically unattainable with current diagnostic tests. Although there is utility in monitoring for infection and serological markers in trachoma surveillance, it is important that adequate considerations are made to ensure evidence-based and achievable guidelines for their utility are put in place. CONCLUSIONS/SIGNIFICANCE: The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons for trachoma surveillance, pre- and post-validation. The use of a monetary reward for identification of TT cases and further exploration into the use of infection and serological indicators particularly in a post-validation setting to assist in identifying recrudescence would be of particular relevance. The next step would be a real-world evaluation of their relative applicability for trachoma surveillance.


Assuntos
Dracunculus/microbiologia , Oncocercose , Saúde Pública , Tracoma/epidemiologia , Animais , Bases de Dados Factuais , Erradicação de Doenças , Dracunculíase/epidemiologia , Inquéritos Epidemiológicos , Humanos , Prevalência , Triquíase/epidemiologia
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