-
The American Journal of Tropical... Dec 2020The success of the Guinea Worm (GW) Eradication Program over the past three decades has been tempered by the persistence of GW disease in a few African nations and the...
The success of the Guinea Worm (GW) Eradication Program over the past three decades has been tempered by the persistence of GW disease in a few African nations and the potential for a future resurgence in cases. Domestic dogs are now a major concern as a disease reservoir as large numbers of cases of canine GW disease are now reported each year, mainly along the Chari River in Chad. As a first step toward the development of a serologic assay for dogs, archived human plasma samples from dracunculiasis-positive donors from Togo were used to select adult female GW antigens for peptide sequencing and cloning. Eight protein sequences of interest were expressed as recombinant glutathione--transferase (GST) fusion proteins, and the most promising proteins were coupled to carboxylated microspheres for use in multiplex assays. A thioredoxin-like protein (TRXL1) and a domain of unknown function (DUF148) were assessed for total IgG and IgG reactivities using a panel of specimens from GW cases, uninfected donors, and individuals infected with various nematode worms, including . Both the DUF148-GST and the TRXL1-GST assays cross-reacted with sera, but the latter assay was always the more specific. The IgG and total IgG TRXL1-GST assays both had sensitivities > 87% and specificities > 90%. Maximum specificity (> 96%) was obtained with the total IgG assay when reactivity to both antigens was used to define a positive case. Given the good performance of the human assay, we are now working to modify the assay for dog assessments.
Topics: Animals; Antibodies, Helminth; Antigens, Helminth; Blotting, Western; Cross Reactions; Disease Eradication; Disease Reservoirs; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Electrophoresis, Polyacrylamide Gel; Glutathione Transferase; Humans; Immunoglobulin G; Onchocerca volvulus; Onchocerciasis; Recombinant Fusion Proteins; Sensitivity and Specificity; Serologic Tests; Thioredoxins
PubMed: 32901602
DOI: 10.4269/ajtmh.20-0511 -
Frontiers in Veterinary Science 2020
PubMed: 32851003
DOI: 10.3389/fvets.2020.00404 -
Emerging Infectious Diseases Aug 2020A fragment of a Dracunculus-like worm was extracted from the hind limb of a 2-year-old dog from Toledo, Spain. Cytochrome oxidase I and rRNA sequences confirmed an...
A fragment of a Dracunculus-like worm was extracted from the hind limb of a 2-year-old dog from Toledo, Spain. Cytochrome oxidase I and rRNA sequences confirmed an autochthonous mammalian Dracunculus worm infection in Europe. Sequence analyses suggest close relation to a parasite obtained from a North American opossum.
Topics: Animals; Dogs; Dracunculiasis; Dracunculus Nematode; Europe; Spain
PubMed: 32687046
DOI: 10.3201/eid2608.201661 -
Transboundary and Emerging Diseases Mar 2021The global programme for the eradication of Guinea worm disease, caused by the parasitic nematode Dracunculus medinensis, has been successful in driving down human...
The global programme for the eradication of Guinea worm disease, caused by the parasitic nematode Dracunculus medinensis, has been successful in driving down human cases, but infections in non-human animals, particularly domestic dogs (Canis familiaris), now present a major obstacle to further progress. Dog infections have mainly been found in Chad and, to a lesser extent, in Mali and Ethiopia. While humans classically acquire infection by drinking water containing infected copepods, it has been hypothesized that dogs might additionally or alternatively acquire infection via a novel pathway, such as consumption of fish or frogs as possible transport or paratenic hosts. We characterized the ecology of free-ranging dogs living in three villages in Gog woreda, Gambella region, Ethiopia, in April-May 2018. We analysed their exposure to potential sources of Guinea worm infection and investigated risk factors associated with infection histories. The home ranges of 125 dogs and their activity around water sources were described using GPS tracking, and the diets of 119 dogs were described using stable isotope analysis. Unlike in Chad, where Guinea worm infection is most frequent, we found no ecological or behavioural correlates of infection history in dogs in Ethiopia. Unlike in Chad, there was no effect of variation among dogs in their consumption of aquatic vertebrates (fish or frogs) on their infection history, and we found no evidence to support hypotheses for this novel transmission pathway in Ethiopia. Dog owners had apparently increased the frequency of clean water provision to dogs in response to previous infections. Variations in dog ranging behaviour, owner behaviour and the characteristics of natural water bodies all influenced the exposure of dogs to potential sources of infection. This initial study suggests that the classical transmission pathway should be a focus of attention for Guinea worm control in non-human animals in Ethiopia.
Topics: Animals; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Ethiopia; Female; Humans; Male
PubMed: 32615005
DOI: 10.1111/tbed.13711 -
PLoS Neglected Tropical Diseases May 2020After 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,...
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.
Topics: Animals; Chad; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Epidemiological Monitoring; Female; Humans; Male
PubMed: 32463811
DOI: 10.1371/journal.pntd.0008207 -
PLoS Neglected Tropical Diseases Apr 2020Global eradication of human Guinea worm disease (dracunculiasis) has been set back by the emergence of infections in animals, particularly domestic dogs Canis...
Global eradication of human Guinea worm disease (dracunculiasis) has been set back by the emergence of infections in animals, particularly domestic dogs Canis familiaris. The ecology and epidemiology of this reservoir is unknown. We tracked dogs using GPS, inferred diets using stable isotope analysis and analysed correlates of infection in Chad, where numbers of Guinea worm infections are greatest. Dogs had small ranges that varied markedly among villages. Diets consisted largely of human staples and human faeces. A minority of ponds, mostly <200 m from dog-owning households, accounted for most dog exposure to potentially unsafe water. The risk of a dog having had Guinea worm was reduced in dogs living in households providing water for animals but increased with increasing fish consumption by dogs. Provision of safe water might reduce dog exposure to unsafe water, while prioritisation of proactive temephos (Abate) application to the small number of ponds to which dogs have most access is recommended. Fish might have an additional role as transport hosts for Guinea worm, by concentrating copepods infected with worm larvae.
Topics: Animals; Chad; Diet; Disease Reservoirs; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Ecology; Family Characteristics; Feces; Female; Fishes; Humans; Water
PubMed: 32310976
DOI: 10.1371/journal.pntd.0008170 -
International Journal of Infectious... Jun 2020The global Guinea Worm Eradication Program has reduced numbers of human infections of Guinea worm disease (dracunculiasis) to 49 cases in four countries. However,...
Cooking copepods: The survival of cyclopoid copepods (Crustacea: Copepoda) in simulated provisioned water containers and implications for the Guinea Worm Eradication Program in Chad, Africa.
INTRODUCTION
The global Guinea Worm Eradication Program has reduced numbers of human infections of Guinea worm disease (dracunculiasis) to 49 cases in four countries. However, infections of domestic animals (dogs and cats) have recently been recognized and are increasing. Typically, Guinea worm (Dracunculus medinensis) transmission occurs via the ingestion of copepods from water. Despite several interventions, including tethering of dogs while worms emerge, the number of infected dogs continue to increase. One hypothesis is that dogs could be infected through the ingestion of copepods in provisioned water.
OBJECTIVES
The purpose of this study was to determine whether copepods can survive in water containers under typical Chadian temperatures.
METHODS
Four container types (plastic, glass, gourd, and metal) were seeded with copepods and exposed to simulated Chadian temperatures.
RESULTS
All copepods in the metal containers died within 4 h. Conversely, after 8 h live copepods were still present in plastic, glass, and gourd containers.
CONCLUSIONS
If provisioned water is provided to potential hosts of D. medinensis, metal containers create the most inhospitable environment for copepods. Plastic containers have little effect on copepod mortality. The use of metal containers for water provisions could be a useful tool assisting with the interruption of D. medinensis transmission among dogs.
Topics: Animals; Chad; Copepoda; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Infection Control; Water
PubMed: 32173575
DOI: 10.1016/j.ijid.2020.03.016 -
Bulletin de La Societe de Pathologie... 2019
[Tribute to Professor Ogobara Doumbo: Symposium Organized by the COPED (Committee for Developing Countries) of the French Academy of Sciences - April 11, 2019, Simone and Cino del Duca Foundation].
Topics: Academies and Institutes; Africa South of the Sahara; Developing Countries; Dracunculiasis; France; History, 20th Century; History, 21st Century; Humans; Malaria; Mali; Tropical Medicine
PubMed: 32003195
DOI: 10.3166/bspe-2019-0101 -
Scientific Reports Jan 2020Dracunculus medinensis, the causative agent of Guinea worm disease in humans, is being reported with increasing frequency in dogs. However, the route(s) of transmission...
Dracunculus medinensis, the causative agent of Guinea worm disease in humans, is being reported with increasing frequency in dogs. However, the route(s) of transmission to dogs is still poorly understood. Classical transmission to humans occurs via drinking water that contains cyclopoid copepods infected with third stage larvae of D. medinensis, but due to the method of dog drinking (lapping) compared to humans (suction and/or retrieval of water into containers), it seems unlikely that dogs would ingest copepods readily through drinking. We exposed lab raised beagles to varying densities of uninfected copepods in 2 liters of water to evaluate the number of copepods ingested during a drinking event. We confirmed dogs can ingest copepod intermediate hosts while drinking; however, low numbers were ingested at the densities that are typically observed in Chad suggesting this transmission route may be unlikely. Overall, the relative importance of the classic transmission route and alternate transmission routes, such as paratenic and transport hosts, needs investigation in order to further clarify the epidemiology of guinea worm infections in dogs.
Topics: Animals; Chad; Communicable Disease Control; Copepoda; Disease Vectors; Dogs; Dracunculiasis; Dracunculus Nematode; Eating; Female; Humans; Male
PubMed: 31996759
DOI: 10.1038/s41598-020-58191-4 -
The National Medical Journal of India 2019Dracunculiasis or guinea-worm infection is a water-borne, parasitic disease that can cause major morbidity. Dracunculiasis in patients with diabetes can be misdiagnosed...
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.
Topics: Abscess; Animals; Diabetes Mellitus, Type 2; Diabetic Foot; Diagnosis, Differential; Dracunculiasis; Dracunculus Nematode; Drinking Water; Foot; Humans; India; Male; Middle Aged
PubMed: 31823935
DOI: 10.4103/0970-258X.272111