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Critical Reviews in Toxicology Feb 2022Temephos (,,','-tetramethyl ,'-thiodi--phenylene bis(phosphorothioate)) is a larvicide belonging to the family of organophosphate pesticides used for the control of... (Review)
Review
Temephos (,,','-tetramethyl ,'-thiodi--phenylene bis(phosphorothioate)) is a larvicide belonging to the family of organophosphate pesticides used for the control of different vectors of diseases, such as dengue, Zika, chikungunya, and dracunculiasis. The aim of this review was to discuss the available published information about temephos toxicokinetics and toxicity in mammals. Temephos is quickly absorbed in the gastrointestinal tract, distributed to all organs, and then it accumulates mainly in adipose tissue. It is metabolized by -oxidation, oxidative desulfuration, and hydrolysis reactions, with the possible participation of cytochrome P450 (CYP). Temephos is mainly eliminated by feces, whereas some of its metabolites are eliminated by urine. The World Health Organization classifies it as class III: slightly dangerous with a NOAEL (no-observed adverse effect level) of 2.3 mg/kg/day for up to 90 days in rats, based on brain acetylcholinesterase (AChE) inhibition. A LOAEL (lowest observable adverse effect level) of 100 mg/kg/day for up to 44 days in rats was proposed based on cholinergic symptoms. However, some studies have shown that temephos causes toxic effects in mammals. The inhibition of the enzyme acetylcholinesterase (AChE) is one of its main demonstrated effects; however, this larvicide has also shown genotoxic effects and some adverse effects on male reproduction and fertility, as well as liver damage, even at low doses. We performed an extensive review through several databases of the literature about temephos toxicokinetics, and we recommend to revisit current assessment of temephos with the new available data.
Topics: Acetylcholinesterase; Animals; Insecticides; Male; Mammals; Rats; Temefos; Zika Virus; Zika Virus Infection
PubMed: 35608007
DOI: 10.1080/10408444.2022.2065967 -
Parasitology Oct 2017Guinea worm disease, dracunculiasis or dracontiasis, is an ancient disease with records going back over 4500 years, but until the beginning of the 20th century, little... (Review)
Review
Guinea worm disease, dracunculiasis or dracontiasis, is an ancient disease with records going back over 4500 years, but until the beginning of the 20th century, little was known about its life cycle, particularly how humans became infected. In 1905, Robert Thomas Leiper was sent by the British colonial authorities to West Africa to investigate the spread of Guinea worm disease and to recommend measures to prevent it. While carrying out his investigations, he made important contributions to the aetiology, epidemiology and public health aspects of Guinea worm disease and provided definitive answers to many outstanding questions. First, he tested the validity of previous theories; second, he confirmed the role of water fleas, which he identified as Cyclops, as the intermediate hosts in the life cycle; third, he investigated the development of the parasite in its intermediate host; and fourth, he recommended measures to prevent the disease. [The crustacean Order Cyclopoida in the Family Cyclopidae contains 25 genera, including Cyclops which itself contains over 400 species and may not even be a valid taxon. It is not known how many of these species (or indeed species belonging to related genera) can act as intermediate hosts of Dracunculus medinensis nor do we know which species Fedchenko, Leiper and other workers used in their experiments. It is, therefore, best to use the terms copepod, or copopoid crustacean rather than Cyclops in scientific texts. In this paper, these crustaceans are referred to as copepods except when referring to an original text.] Leiper described the remarkable changes that took place when an infected copepod was placed in a dilute solution of hydrochloric acid; the copepod was immediately killed, but the Dracunculus larvae survived and were released into the surrounding water. From this, he concluded that if a person swallowed an infected copepod, their gastric juice would produce similar results. He next infected monkeys by feeding them copepods infected with Guinea worm larvae, and thus conclusively demonstrated that humans became infected by accidentally ingesting infected crustaceans. Based on these conclusions, he advocated a number of control policies, including avoidance of contaminated drinking water or filtering it, and these preventive measures paved the way for further research. The challenge to eradicate Guinea worm disease was not taken up until about seven decades later since when, with the support of a number of governmental and non-governmental organizations, the number of cases has been reduced from an estimated 3·5 million in 1986 to 25 in 2016 with the expectation that this will eventually lead to the eradication of the disease.
Topics: Africa, Western; Animals; Communicable Disease Control; Disease Eradication; Dracunculiasis; Dracunculus Nematode; History, 20th Century; Public Health
PubMed: 28653590
DOI: 10.1017/S0031182017000683 -
Tropical Medicine and Infectious Disease Nov 2022Dracunculiasis, also known as Guinea worm disease (GWD), is a neglected tropical disease (NTD) caused by a parasite (). In the past, dracunculiasis was known as "the... (Review)
Review
BACKGROUND
Dracunculiasis, also known as Guinea worm disease (GWD), is a neglected tropical disease (NTD) caused by a parasite (). In the past, dracunculiasis was known as "the disease of the empty granary" because of the difficulties patients had in going to work in fields or to school when affected by this disease. In tropical areas, the condition has been widespread in economically disadvantaged communities, and has been associated with reduced economic status and low levels of education.
METHODS
we searched PubMed, Scopus, Google Scholar, EMBASE, Cochrane Library, and WHO websites for literature addressing dracunculiasis published in the last 50 years.
RESULTS
by development and optimization of multi-layered control measures, transmission by the vector has been interrupted, but there are foci in several African countries with a high risk of compromising the results obtained in the control of this neglected disease.
CONCLUSION
this review features state-of-the-art data on the infection prevalence, geographical distribution, diagnostics, parasite-host interactions, and the pathology of dracunculiasis. Also described are the current state and future perspectives for vector control and elimination strategies.
PubMed: 36355908
DOI: 10.3390/tropicalmed7110366 -
Journal of Theoretical Biology Nov 2017Simple models of disease propagation often disregard the effects of transmission heterogeneity on the ecological and epidemiological dynamics associated with...
Simple models of disease propagation often disregard the effects of transmission heterogeneity on the ecological and epidemiological dynamics associated with host-parasite interactions. However, for some diseases like schistosomiasis, a widespread parasitic infection caused by Schistosoma worms, accounting for heterogeneity is crucial to both characterize long-term dynamics and evaluate opportunities for disease control. Elaborating on the classic Macdonald model for macroparasite transmission, we analyze families of models including explicit descriptions of heterogeneity related to differential transmission risk within a community, water contact patterns, the distribution of the snail host population, human mobility, and the seasonal fluctuations of the environment. Through simple numerical examples, we show that heterogeneous multigroup communities may be more prone to schistosomiasis than homogeneous ones, that the availability of multiple water sources can hinder parasite transmission, and that both spatial and temporal heterogeneities may have nontrivial implications for disease endemicity. Finally, we discuss the implications of heterogeneity for disease control. Although focused on schistosomiasis, results from this study may apply as well to other parasitic infections with complex transmission cycles, such as cysticercosis, dracunculiasis and fasciolosis.
Topics: Animals; Endemic Diseases; Humans; Models, Biological; Schistosoma; Schistosomiasis; Time Factors
PubMed: 28823529
DOI: 10.1016/j.jtbi.2017.08.015 -
Journal of the European Academy of... Dec 2022Itch is the most common skin symptom among tropical parasitic diseases (TPD), but there are limited data about its characteristics in these conditions. In dermatology... (Review)
Review
Itch is the most common skin symptom among tropical parasitic diseases (TPD), but there are limited data about its characteristics in these conditions. In dermatology practices and travellers' health clinics in the developed world, itch is a common complaint among travellers returning from endemic areas, as well among migrants arriving from endemic areas, where they may have been exposed to TPD. Studying aspects of pruritus among TPD may lead to improvements in prompt, accurate diagnosis and management of these conditions. This review examines the major itch-inducing TPDs, including schistosomiasis, echinococcosis, onchocerciasis, scabies, cutaneous larva migrans, larva currens, African trypanosomiasis, dracunculiasis and other causes of travel associated pruritus. We focus on the link between pruritus and other symptoms, aetiology, clinical staging and therapeutic options for these parasitic illnesses. Because some tropical parasitic diseases can present with significant pruritus, we attempt to identify aspects of the pruritus that are characteristic of-or unique to-specific conditions. These diagnostic insights may help clinicians create a rational and focused differential diagnosis and help determine optimal disease management pathways. In this sense, management involves treating the individual, seeking epidemiologically linked cases, preventing recurrences or relapses, and reducing spread of the disease.
Topics: Humans; Travel; Larva Migrans; Parasitic Diseases; Emigrants and Immigrants; Pruritus
PubMed: 35793476
DOI: 10.1111/jdv.18408 -
Journal of the American Academy of... Dec 2015In the 21st century, despite increased international travel for vacation, work, and medical missions and immigration into the United States, there is little published in... (Review)
Review
In the 21st century, despite increased international travel for vacation, work, and medical missions and immigration into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. It has been estimated that 20% to 70% of international travelers suffer from some travel-related health problem. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on cutaneous diseases caused by helminth infections. Part I of the review focused on nematode infections; part II will focus on trematode and cestode infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.
Topics: Animals; Anticestodal Agents; Antiplatyhelmintic Agents; Biopsy, Needle; Cestoda; Cestode Infections; Disease Progression; Endemic Diseases; Female; Humans; Immunohistochemistry; Incidence; Larva Migrans; Male; Rare Diseases; Risk Assessment; Skin Diseases, Parasitic; Travel; Treatment Outcome; Trematoda; Trematode Infections; Tropical Climate
PubMed: 26568338
DOI: 10.1016/j.jaad.2014.11.035 -
The American Journal of Tropical... Aug 2018This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2017. Dracunculiasis (guinea worm disease) has been eliminated from...
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 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.
Topics: Animals; Chad; Disease Eradication; Dogs; Dracunculiasis; Dracunculus Nematode; Epidemiological Monitoring; Ethiopia; Female; Global Health; Humans; Male; Water Supply
PubMed: 29869608
DOI: 10.4269/ajtmh.18-0204 -
MMWR. Morbidity and Mortality Weekly... Nov 2021Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is traditionally acquired by drinking water containing copepods (water fleas)...
Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is traditionally acquired by drinking water containing copepods (water fleas) infected with D. medinensis larvae, but in recent years also appears increasingly to be transmitted by eating fish or other aquatic animals. The worm typically emerges through the skin on a lower limb of the host 1 year after infection, causing pain and disability (1). There is no vaccine or medicine to prevent or medicine to treat dracunculiasis; eradication relies on case containment* to prevent water contamination and other interventions to prevent infection: health education, water filtration, treatment of unsafe water with temephos (an organophosphate larvicide), and provision of safe drinking water (1,2). The eradication campaign began in 1980 at CDC (1). In 1986, with an estimated 3.5 million cases occurring annually in 20 African and Asian countries (3), the World Health Assembly called for dracunculiasis elimination (4). The Guinea Worm Eradication Program (GWEP), led by The Carter Center and supported by the World Health Organization (WHO), UNICEF, CDC, and other partners, began assisting ministries of health in countries with endemic disease. With 27 cases in humans reported in 2020, five during January-June 2021, and only six countries currently affected by dracunculiasis (Angola, Chad, Ethiopia, Mali, South Sudan, and importations into Cameroon), achievement of eradication appears to be close. However, dracunculiasis eradication is challenged by civil unrest, insecurity, and epidemiologic and zoologic concerns. Guinea worm infections in dogs were first reported in Chad in 2012. Animal infections have now overtaken human cases, with 1,601 reported animal infections in 2020 and 443 during January-June 2021. Currently, all national GWEPs remain fully operational, with precautions taken to ensure safety of program staff and community members in response to the COVID-19 pandemic. Because of COVID-19, The Carter Center convened the 2020 and 2021 annual GWEP Program Managers meetings virtually, and WHO's International Commission for the Certification of Dracunculiasis Eradication met virtually in October 2020. Since 1986, WHO has certified 199 countries, areas, and territories dracunculiasis-free. Six countries are still affected: five with endemic disease and importations into Cameroon. Seven countries (five with endemic dracunculiasis, Democratic Republic of the Congo, and Sudan) still lack certification (4). The existence of infected dogs, especially in Chad, and impeded access because of civil unrest and insecurity in Mali and South Sudan are now the greatest challenges to interrupting transmission. This report describes progress during January 2020-June 2021 and updates previous reports (2,4,5).
Topics: Disease Eradication; Dracunculiasis; Global Health; Humans
PubMed: 34735420
DOI: 10.15585/mmwr.mm7044a1 -
Journal of the Neurological Sciences Feb 2015The World Health Organization has identified 17 neglected tropical diseases (NTDs) that disproportionately affect the world's poorest populations. The neurologic aspects... (Review)
Review
BACKGROUND
The World Health Organization has identified 17 neglected tropical diseases (NTDs) that disproportionately affect the world's poorest populations. The neurologic aspects of many of these NTDs have received relatively little attention.
METHODS
A review was performed in PubMed (MedLine) for each NTD by disease name, name of its causative organism, and neurology, neurosurgery, neurologist, brain, spinal cord, peripheral nerve, muscle, nervous system, encephalitis, meningitis, encephalopathy, stroke, neuropathy, and myopathy (1968-Sept. 2013). The Oxford Center for Evidence-based Medicine guidelines were used to determine the level of evidence of neurological involvement and treatment based on the reports identified.
RESULTS
Neurologic manifestations were reported for all NTDs except yaws. Neurologic involvement was described in systematic reviews for four NTDs (Chagas disease, echinococcosis, rabies, cysticercosis) (levels 2a-3a), retrospective cohort studies for six (dengue, human African trypanosomiasis, leishmaniasis, leprosy, onchocerciasis, schistosomiasis) (levels 2b-3b), case series for one (foodborne trematodiasis) (level 4), and case reports for five (Buruli ulcer, dracunculiasis, filariasis, soil-transmitted helminthes, and trachoma). Level 1 evidence for treatment of neurologic manifestations of NTDs was found for human African trypanosomiasis, leprosy, and cysticercosis and level 2 evidence exists for treatment of neurologic involvement in Chagas disease. For the remaining NTDs, treatment of neurologic complications is described in case series and case reports only.
CONCLUSIONS
Neurologic manifestations of NTDs cause significant morbidity and mortality, although limited evidence exists on how best to treat these neurologic complications. Increased awareness of neurologic manifestations of the NTDs can increase their early identification and treatment, contributing to ongoing elimination and eradication campaigns.
Topics: Brain; Evidence-Based Medicine; Humans; Neglected Diseases; Peripheral Nervous System; Retrospective Studies; Spinal Cord; Tropical Medicine
PubMed: 25623803
DOI: 10.1016/j.jns.2015.01.001 -
Revue Medicale Suisse Oct 2019
Topics: Dracunculiasis; Humans
PubMed: 31663710
DOI: No ID Found