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Lancet (London, England) Jan 2018More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and... (Review)
Review
More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and Necator americanus), Trichuris trichiura, and Strongyloides stercoralis. Infected children and adults present with a range of medical and surgical conditions, and clinicians should consider the possibility of infection in individuals living in, or returning from, endemic regions. Although safe and effective drugs are donated free to endemic countries, only half of at-risk children received treatment in 2016. This Seminar describes the epidemiology, lifecycles, pathophysiology, clinical diagnosis, management, and public health control of soil-transmitted helminths. Previous work has questioned the effect of population-level deworming; however, it remains beyond doubt that treatment reduces the severe consequences of soil-transmitted helminthiasis. We highlight the need for refined diagnostic tools and effective control options to scale up public health interventions and improve clinical detection and management of these infections.
Topics: Anthelmintics; Helminthiasis; Humans; Public Health; Soil
PubMed: 28882382
DOI: 10.1016/S0140-6736(17)31930-X -
Transactions of the Royal Society of... Jan 2017Worms have co-evolved with humans over millions of years. To survive, they manipulate host systems by modulating immune responses so that they cause (in the majority of... (Review)
Review
Worms have co-evolved with humans over millions of years. To survive, they manipulate host systems by modulating immune responses so that they cause (in the majority of hosts) relatively subtle harm. Anthelminthic treatment has been promoted as a measure for averting worm specific pathology and to mitigate subtle morbidities which may include effects on anaemia, growth, cognitive function and economic activity. With our changing environment marked by rapid population growth, urbanisation, better hygiene practices and anthelminthic treatment, there has been a decline in worm infections and other infectious diseases and a rise in non-communicable diseases such as allergy, diabetes and cardiovascular disease. This review reflects upon our age-old interaction with worms, and the broader ramifications of life without worms for vaccine responses and susceptibility to other infections, and for allergy-related and metabolic disease. We touch upon the controversy around the benefits of mass drug administration for the more-subtle morbidities that have been associated with worm infections and then focus our attention on broader, additional aspects of life without worms, which may be either beneficial or detrimental.
Topics: Animals; Anthelmintics; Cardiovascular Diseases; Communicable Diseases; Helminthiasis; Helminths; Host-Parasite Interactions; Humans; Hypersensitivity; Metabolic Diseases; Vaccines
PubMed: 28340138
DOI: 10.1093/trstmh/trx010 -
PLoS Neglected Tropical Diseases Mar 2022Schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) are known to be endemic in Yemen. However, the distribution of both diseases had not previously been...
BACKGROUND
Schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) are known to be endemic in Yemen. However, the distribution of both diseases had not previously been assessed by a well-structured national mapping study covering all governorates. The main aim of this study was, therefore, to map the prevalence of SCH and STH in Yemen in order to better inform implementation of effective national control and elimination interventions. The assessment of the distribution of anaemia was also included as a well-known consequence of infection with both SCH and STH. Secondarily, the study aimed to provide a broad indication of the impact of large-scale treatment on the distribution of infection.
METHODOLOGY AND PRINCIPAL FINDINGS
To achive these aims, 80,432 children (10-14 years old) from 2,664 schools in 332 of Yemen's 333 districts were included, in 2014, into this national cross-sectional survey. Countrywide, 63.3% (210/332) and 75.6% (251/332) of districts were found to be endemic for SCH and STH respectively. More districts were affected by intestinal than urogenital SCH (54.2% and 31.6% respectively). SCH infection was mostly mild and moderate, with no districts reporting high infection. One quarter (24.4%) of Yemeni districts had high or moderate levels of Ascaris lumbricoides infection. Infection with Trichuris trichiura was the second most common STH (44.9% of districts infected) after A. lumbricoides (68.1%). Hookworm was the least prevalent STH (9.0%). Anaemia was prevalent in 96.4% of districts; it represented a severe public health problem (prevalence ≥ 40%) in 26.5% of districts, and a mild to moderate problem in two thirds of the districts (33.7% and 36.1% respectively).
CONCLUSION
This study provided the first comprehensive mapping of SCH, STH, and anaemia across the country. This formed the basis for evaluating and continuing the national control and elimination programme for these neglected tropical diseases in Yemen.
Topics: Adolescent; Anemia; Animals; Ascariasis; Child; Cross-Sectional Studies; Feces; Helminthiasis; Helminths; Humans; Neglected Diseases; Prevalence; Schistosomiasis haematobia; Soil; Yemen
PubMed: 35333859
DOI: 10.1371/journal.pntd.0010092 -
Trends in Parasitology Jan 2016Vitamin A deficiency (VAD) and soil-transmitted helminthiasis (STH) represent two widely prevalent and often overlapping global health problems. Approximately 75% of... (Review)
Review
Vitamin A deficiency (VAD) and soil-transmitted helminthiasis (STH) represent two widely prevalent and often overlapping global health problems. Approximately 75% of countries with moderate or severe VAD are coendemic for STH. We reviewed the literature on the complex relationship between STH and VAD. Treatment for STH significantly increases provitamin A (e.g., β-carotene) levels but is associated with minimal increases in preformed vitamin A (retinol). Interpretation of the data is complicated by variations in STH infection intensity and limitations of vitamin A biomarkers. Despite these challenges, increased coordination of STH and VAD interventions represents an important public health opportunity.
Topics: Global Health; Health Policy; Helminthiasis; Humans; Socioeconomic Factors; Soil; Vitamin A Deficiency
PubMed: 26724966
DOI: 10.1016/j.pt.2015.11.007 -
Infectious Diseases of Poverty Mar 2017Even though Rwanda lies within a region that has a high prevalence of schistosomiasis and soil-transmitted helminth (STH) infections, epidemiological information... (Review)
Review
Even though Rwanda lies within a region that has a high prevalence of schistosomiasis and soil-transmitted helminth (STH) infections, epidemiological information regarding these infections in the country remains scarce. The present review attempts to compile the available data on schistosomiasis and STHs, from 1940 to 2014, to provide an insight on the epidemiological profile of these infections. This information will, in turn, support the design and implementation of sustainable control measures. The available records indicate that only Schistosoma mansoni and all the major species of STHs are endemic in Rwanda. In 2008, the national prevalence of S. mansoni was reported to be 2.7%, ranging from 0 to 69.5%, and that of STH infections was 65.8% (diagnosed using the Kato-Katz technique). The prevalence of these infections varies from one district to another, with schoolchildren remaining a highly affected group. The main control approach is mass drug administration using albendazole and praziquantel, mostly targeting school-aged children in school environments. In 2008, adult individuals living in areas with a prevalence of S. mansoni ≥30% were also included in the mass drug administration programme. However, despite Rwanda achieving an almost 100% coverage of this programme in 2008-2010, the transmission of S. mansoni and STHs continues to take place, as illustrated by the most recent surveys. If Rwanda is to achieve sustainable control and elimination of schistosomiasis and STHs, there is a need to revise the country's control strategy and adopt an integrated control approach that involves a combination of measures.
Topics: Albendazole; Animals; Anthelmintics; Communicable Disease Control; Disease Transmission, Infectious; Endemic Diseases; Helminthiasis; Humans; Praziquantel; Prevalence; Rwanda
PubMed: 28245883
DOI: 10.1186/s40249-016-0212-z -
Parasite Immunology Aug 2014It has been proposed that helminth infection may be particularly detrimental during pregnancy, through adverse effects on maternal anaemia and on birth outcomes, and... (Review)
Review
It has been proposed that helminth infection may be particularly detrimental during pregnancy, through adverse effects on maternal anaemia and on birth outcomes, and that anthelminthic treatment during pregnancy will therefore be particularly beneficial. However, the few treatment trials that have been conducted have given, but little support to this notion and further trials in settings of nutritional stress are needed. It has also been proposed that prenatal exposure to helminth infection has an important effect on the development of the foetal immune response. There is evidence that this may impact, long-term, upon responses to helminth and nonhelminth antigens, and to allergens. Exposure to helminths in utero may also have nonspecific effects that may modify the offspring's susceptibility to diseases mediated by inflammation, including metabolic disorders. The mechanisms of such effects are not known, but they deserve to be explored as current epidemiological findings suggest the possibility of primary prevention for inflammatory conditions such as allergy, through intervention during pregnancy.
Topics: Anthelmintics; Female; Helminthiasis; Humans; Pregnancy; Pregnancy Complications, Parasitic; Risk Factors
PubMed: 24471654
DOI: 10.1111/pim.12101 -
The Lancet. Infectious Diseases Feb 2017In 2001, the World Health Assembly (WHA) passed the landmark WHA 54.19 resolution for global scale-up of mass administration of anthelmintic drugs for morbidity control... (Review)
Review
In 2001, the World Health Assembly (WHA) passed the landmark WHA 54.19 resolution for global scale-up of mass administration of anthelmintic drugs for morbidity control of schistosomiasis and soil-transmitted helminthiasis, which affect more than 1·5 billion of the world's poorest people. Since then, more than a decade of research and experience has yielded crucial knowledge on the control and elimination of these helminthiases. However, the global strategy has remained largely unchanged since the original 2001 WHA resolution and associated WHO guidelines on preventive chemotherapy. In this Personal View, we highlight recent advances that, taken together, support a call to revise the global strategy and guidelines for preventive chemotherapy and complementary interventions against schistosomiasis and soil-transmitted helminthiasis. These advances include the development of guidance that is specific to goals of morbidity control and elimination of transmission. We quantify the result of forgoing this opportunity by computing the yearly disease burden, mortality, and lost economic productivity associated with maintaining the status quo. Without change, we estimate that the population of sub-Saharan Africa will probably lose 2·3 million disability-adjusted life-years and US$3·5 billion of economic productivity every year, which is comparable to recent acute epidemics, including the 2014 Ebola and 2015 Zika epidemics. We propose that the time is now to strengthen the global strategy to address the substantial disease burden of schistosomiasis and soil-transmitted helminthiasis.
Topics: Africa South of the Sahara; Anthelmintics; Global Health; Guidelines as Topic; Helminthiasis; Humans; Morbidity; Quality-Adjusted Life Years; Schistosomiasis; Soil
PubMed: 27914852
DOI: 10.1016/S1473-3099(16)30535-7 -
The American Journal of Tropical... Sep 2016Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and... (Review)
Review
Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and Ascaris lumbricoides) has relied on often-insensitive microscopy techniques. Over the past several years, there has been an effort to use molecular diagnostics, particularly quantitative polymerase chain reaction (qPCR), to detect intestinal pathogens. While some platforms have been approved by regulatory bodies (e.g., Food and Drug Administration) to detect intestinal bacteria, viruses, and protozoa, there are no approved tests currently available for STH. Although studies comparing qPCR to microscopy methods for STH are imperfect, due in large part to a lack of a sufficient gold standard, they do show a significant increase in sensitivity and specificity of qPCR compared with microscopic techniques. These studies, as well as the advantages and disadvantages of using qPCR for STH diagnosis, are discussed. Guidelines for those designing future studies utilizing qPCR are proposed for optimizing results, as is the proposition for using standardized molecular diagnostics routinely for STH in clinical laboratories and for field-based studies when possible.
Topics: Helminthiasis; Humans; Molecular Diagnostic Techniques; Polymerase Chain Reaction; Sensitivity and Specificity; Soil
PubMed: 27481053
DOI: 10.4269/ajtmh.16-0266 -
Parasitology Research Dec 2023The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals... (Review)
Review
The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals provides comprehensive awareness and potential solutions for issues relating to the health of people, animals, and the environment. This approach has increasingly gained appeal as the standard strategy for tackling emerging infectious diseases, most of which are zoonoses. Treatment with anthelmintics (AHs) without a doubt minimizes the severe consequences of soil-transmitted helminths (STHs); however, evidence of anthelmintic resistance (AR) development to different helminths of practically every animal species and the distinct groups of AHs is overwhelming globally. In this regard, the correlation between the application of anthelmintic drugs in both human and animal populations and the consequent development of anthelmintic resistance in STHs within the context of a One-Health framework is explored. This review provides an overview of the major human and animal STHs, treatment of the STHs, AR development and drug-related factors contributing towards AR, One-Health and STHs, and an outline of some One-Health strategies that may be used in combating AR.
Topics: Animals; Humans; Helminthiasis; Soil; One Health; Anthelmintics; Helminths
PubMed: 38114766
DOI: 10.1007/s00436-023-08088-8 -
Pathogens and Global Health Apr 2013The relationships between allergic diseases and helminth infections are inconsistent. Some studies have suggested that helminth infections induce or increase the... (Review)
Review
The relationships between allergic diseases and helminth infections are inconsistent. Some studies have suggested that helminth infections induce or increase the severity of atopic diseases. Other studies report that children infected with some helminths have lower prevalence and milder atopic symptoms. Expanding our knowledge on the mechanism of immunological modification as a result of helminth infection, and understanding the interaction between helminth infections and allergic diseases will be useful for developing potentially new treatments using some helminths, and for evaluating the risks and benefits of eradicating helminth infections in endemic areas. This article reviews current knowledge on the mechanisms of allergic disease, the immunological modifications that result from helminth infections, and clinical evidence of the effects of these infections on allergic diseases.
Topics: Helminthiasis; Humans; Hypersensitivity
PubMed: 23683364
DOI: 10.1179/2047773213Y.0000000080