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Tropical Medicine and Infectious Disease Nov 2022Intestinal parasitic infections are common infectious diseases causing many health problems and impaired growth and physical development.. Children under five years old... (Review)
Review
Intestinal parasitic infections are common infectious diseases causing many health problems and impaired growth and physical development.. Children under five years old are the most vulnerable to infections, due to their immature immunity and feeding and exploratory behaviours. This systematic review aimed to assess the relationship between intestinal parasitic infections and undernutrition among children under 5 years old. Fifteen studies met the inclusion and exclusion criteria and were classified as high-quality studies. Twelve parasites were reported, including , spp., , , , hookworm, , , spp. and . Ascariasis is the most reported infection, with a prevalence ranging from 10.77% in Ethiopia to 57.14% in Malaysia, and is correlated with stunting (OR 2.17 (95% CI 1.14, 4.13), = 0.02). Giardiasis is the second most reported infection, with a prevalence ranging from 4.43% in Ethiopia to 66.33% in the Central African Republic, and is related to an increased risk of stunting (OR 2.34 (95% CI 1.07, 5.10), = 0.03)), wasting (OR 2.90 (95% CI 1.12, 7.49, = 0.03)), and being underweight (OR 1.53 (95% CI 1.02, 2.29, = 0.04)). The third and fourth most prevalent infections are and hookworm infections. Intestinal parasitic infections can occur very early in life and cause significant growth retardation. It is important to understand the prevalence and effects of infection based on the parasite species in order to implement therapeutic interventions and prevention controls.
PubMed: 36422922
DOI: 10.3390/tropicalmed7110371 -
Acta Tropica Mar 2023It has been tested and proven that vaccination is still the best strategy to combat infectious diseases. However, to date, there are still no vaccines against human... (Review)
Review
It has been tested and proven that vaccination is still the best strategy to combat infectious diseases. However, to date, there are still no vaccines against human soil-transmitted helminthic diseases, despite their high prevalence globally, particularly in developing countries and rural areas with tropical climates and poor sanitation. The development of vaccines against helminths is riddled with obstacles. Helminths have a complex life cycle, multiple stages within the same host with stage-specific antigen expression, and the ability to regulate host immune reactions to evade the immune response. These elements contribute to the main challenge of helminthic vaccines: the identification of effective vaccine candidates. Therefore, this article reviews the current progress and potential future direction of soil-transmitted helminthic vaccines, particularly against Trichuris trichiura, Ascaris lumbricoides, Strongyloides stercoralis, Necator americanus and Ancylostoma duodenale. The study design employed was a systematic review, using qualitative meta-summary synthesis. Preclinical studies and clinical trials on the development of protein subunit vaccines against the five soil-transmitted helminths were searched on PubMed and Scopus. Effectiveness was indicated by a reduction in worm burden or larval output, an increase in specific IgG levels, or an increase in cytokine production. Our findings show that only the hookworm vaccine against N. americanus is in the clinical trial phase, while the rest is still in exploratory research and pre-clinical development phase.
Topics: Animals; Humans; Soil; Hookworm Infections; Ascaris lumbricoides; Ancylostomatoidea; Necator americanus; Vaccines; Helminthiasis; Feces
PubMed: 36586174
DOI: 10.1016/j.actatropica.2022.106796 -
Water Research X Jan 2023The safe management of fecal sludge from the 3.4 billion people worldwide that use onsite sanitation systems can greatly reduce the global infectious disease burden.... (Review)
Review
The safe management of fecal sludge from the 3.4 billion people worldwide that use onsite sanitation systems can greatly reduce the global infectious disease burden. However, there is limited knowledge about the role of design, operational, and environmental factors on pathogen survival in pit latrines, urine diverting desiccation toilets, and other types of onsite toilets. We conducted a systematic literature review and meta-analysis to characterize pathogen reduction rates in fecal sludge, feces, and human excreta with respect to pH, temperature, moisture content, and the use of additives for desiccation, alkalinization, or disinfection. A meta-analysis of 1,382 data points extracted from 243 experiments described in 26 articles revealed significant differences between the decay rates and T values of pathogens and indicators from different microbial groups. The overall median T values were 4.8 days, 29 days, >341 days, and 429 days for bacteria, viruses, protozoan (oo)cysts, and eggs, respectively. As expected, higher pH values, higher temperatures, and the application of lime all significantly predicted greater pathogen reduction rates but the use of lime by itself was more effective for bacteria and viruses than for eggs, unless urea was also added. In multiple lab-scale experiments, the application of urea with enough lime or ash to reach a pH of 10 - 12 and a sustained concentration of 2,000 - 6,000 mg/L of non-protonated NHN reduced eggs more rapidly than without urea. In general, the storage of fecal sludge for 6 months adequately controls hazards from viruses and bacteria, but much longer storage times or alkaline treatment with urea and low moisture or heat is needed to control hazards from protozoa and helminths. More research is needed to demonstrate the efficacy of lime, ash, and urea in the field. More studies of protozoan pathogens are also needed, as very few qualifying experiments were found for this group.
PubMed: 37250291
DOI: 10.1016/j.wroa.2023.100171 -
Global prevalence of Ascaris infection in humans (2010-2021): a systematic review and meta-analysis.Infectious Diseases of Poverty Nov 2022Ascariasis is one of the most important neglected tropical diseases of humans worldwide. The epidemiology of Ascaris infection appears to have changed with improvements... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Ascariasis is one of the most important neglected tropical diseases of humans worldwide. The epidemiology of Ascaris infection appears to have changed with improvements in sanitation and mass drug administration, but there is no recent information on prevalence worldwide. Here, we performed a systematic review and meta-analysis to assess the global prevalence of human Ascaris infection from 2010 to 2021.
METHODS
We searched MEDLINE/PubMed, and Scopus databases for studies measuring prevalence of Ascaris infection, published between 1 January 2010 and 1 January 2022. We included studies of the general human population in endemic regions, which used accepted coprodiagnostic methods, and excluded studies of people with occupations with an increased risk or probability of ascariasis and/or specific diseases other than ascariasis. We applied random-effects models to obtain pooled prevalence estimates for six sustainable development goal regions of the world. We extrapolated the prevalence estimates to the global population in 2020, to estimate the number of individuals with Ascaris infection. We conducted multiple subgroup and meta-regression analyses to explore possible sources of heterogeneity, and to assess relationships between prevalence estimates and demographic, socio-economic, geo-climatic factors.
RESULTS
Of 11,245 studies screened, we analysed 758 prevalence estimates for a total number of 4,923,876 participants in 616 studies from 81 countries. The global prevalence estimated was 11.01% (95% confidence interval: 10.27-11.78%), with regional prevalences ranging from 28.77% (7.07-57.66%) in Melanesia (Oceania) to 1.39% (1.07-1.74%) in Eastern Asia. We estimated that ~ 732 (682-782) million people harboured Ascaris worldwide in 2021. The infected people in Latin America and the Caribbean region had a higher prevalence of high intensity infection (8.4%, 3.9-14.1%). Prevalence estimates were higher in children, and people in rural communities or in countries or regions with lower income and human development indices. There was a trend for a higher prevalence in regions with increasing mean annual relative humidity, precipitation and environmental temperature.
CONCLUSIONS
Our findings indicate that, despite a renewed commitment by some communities or authorities to control ascariasis, a substantial portion of the world's human population (> 0.7 billion) is infected with Ascaris. Despite the clinical and socioeconomic importance of ascariasis, many past routine surveys did not assess the intensity of Ascaris infection in people. We propose that the present findings might stimulate the development of customised strategies for the improved control and prevention of Ascaris infection worldwide.
Topics: Humans; Child; Ascariasis; Prevalence; Rural Population; Latin America
PubMed: 36401308
DOI: 10.1186/s40249-022-01038-z -
Parasitology Dec 2021Ascariasis is the most prevalent helminth infection in the world and leads to significant, life-long morbidity, particularly in young children. Current efforts to...
Ascariasis is the most prevalent helminth infection in the world and leads to significant, life-long morbidity, particularly in young children. Current efforts to control and eradicate ascariasis in endemic regions have been met with significant challenges including high-rates of re-infection and potential development of anthelminthic drug resistance. Vaccines against ascariasis are a key tool that could break the transmission cycle and lead to disease eradication globally. Evolution of the vaccine pipeline has progressed, however no vaccine product has been brought to human clinical trials to date. Advancement in recombinant protein technology may provide the first step in generating an vaccine as well as a pan-helminthic vaccine ready for human trials. However, several roadblocks remain and investment in new technologies will be important to develop a successful human vaccine that is critically needed to prevent significant morbidity in -endemic regions around the world.
Topics: Animals; Ascariasis; Ascaris; Humans; Vaccine Development; Vaccines
PubMed: 35586777
DOI: 10.1017/s0031182021001347 -
Microbial Pathogenesis Feb 2020There are numerous epidemiological and experimental evidences to suggest that Ascaris lumbricoides infection is a neglected risk factor for development of asthma. For... (Review)
Review
There are numerous epidemiological and experimental evidences to suggest that Ascaris lumbricoides infection is a neglected risk factor for development of asthma. For this purpose, we conducted a systematic review and meta-analysis for better understanding of this relationship. Systematic searching (PubMed, Scopus, Web of Science and Google Scholar) was done, up to September 30, 2019 to identify the relevant studies. We applied random-effects meta-analysis model to generate the overall odds ratio (OR) and 95% confidence intervals (CIs). Heterogeneity was assessed with I and τ statistic. Finally, 19 studies (totally 25 datasets), including 14 datasets with microscopic methods (1830 asthmatic patients (APs) and 3802 healthy controls (HCs)) and 11 datasets with serological methods (1543 APs and 3507 HCs) met the eligibility criteria. Considering to the serological methods, our results demonstrated that the APs had higher seroprevalence rate of A. lumbricoides (48.3% vs. 35.1%) than HCs, showing a significant association (pooled crude OR, 1.53; 95%CI, 1.07-2.18). Moreover, microscopic methods showed a higher prevalence of A. lumbricoides infection in the APs compared to the HCs (37.2% vs. 30.2%), but no significant association was found between APs and HCs (pooled crude OR, 1.19; 95%CI, 0.92-1.55). After adjustment for confounders, results showed no significant association for both serological (pooled adjusted OR, 1.43; 95%CI, 0.93-2.19) and microscopic (pooled adjusted OR, 1.05; 95%CI, 0.78-1.42) methods. Despite heterogeneous results, accurate and better quality studies are needed to determine the effect of A. lumbricoides infection on induction or exacerbation of asthma.
PubMed: 32101769
DOI: 10.1016/j.micpath.2020.104099 -
The Journal of Allergy and Clinical... Jun 2022There is considerable research interest in the role of helminth infections in the development of allergic diseases. However, findings from previous studies are mixed.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
There is considerable research interest in the role of helminth infections in the development of allergic diseases. However, findings from previous studies are mixed. Existing systematic reviews of these studies are outdated. We performed a systematic review of the global literature on the association between helminth infections and development and clinical outcomes of allergic diseases.
METHODS
We searched Cochrane Library, MEDLINE, EMBASE, ISI Web of Science, PubMed, Global Index Medicus, Scielo, KoreaMed, Google Scholar, and Lilacs for studies published up to January 2020. We included observational epidemiological studies (cohort, case-control, and cross-sectional studies) of children and adults reporting associations between helminth infections and asthma, allergic rhinitis, eczema, and atopy. We performed random-effects meta-analysis to summarize the effect estimates.
RESULTS
We included 80 studies with 99,967 participants. In the meta-analyses, we did not observe an overall association between helminth infections and allergic diseases. There was, however, evidence that Ascaris lumbricoides infections were associated with an increased risk of bronchial hyperreactivity in children (risk ratio, 1.41; 95% CI, 1.17-1.70; I = 50; P for I = .09), and were associated with an increased risk of atopy among helminth-infected adults (risk ratio, 1.37; 95% CI, 1.18-1.61; I = 52; P for I = .02). We found no study that addressed the association between helminth infection and clinical outcomes of allergic diseases. The overall strength of the underlying evidence was low to moderate.
CONCLUSIONS
Helminth infections may increase the risk of bronchial hyperreactivity in children and atopy in adults. Well-designed longitudinal cohorts may help clarify potential causal associations between chronic helminth infections and allergic diseases.
Topics: Adult; Animals; Bronchial Hyperreactivity; Child; Cross-Sectional Studies; Helminthiasis; Helminths; Humans; Hypersensitivity, Immediate; Rhinitis, Allergic
PubMed: 34968529
DOI: 10.1016/j.jaci.2021.12.777 -
Parasitology Research Jan 2022Trichuriasis is one of the most common soil-transmitted helminth (STH) infections, affecting populations globally. The condition is particularly prevalent in tropical... (Meta-Analysis)
Meta-Analysis Review
Trichuriasis is one of the most common soil-transmitted helminth (STH) infections, affecting populations globally. The condition is particularly prevalent in tropical and subtropical areas with low levels of sanitation and poor living conditions. The objective of this systematic review and meta-analysis was to evaluate the prevalence of Trichuris trichiura infection in Asia at the country and region level. Multiple databases/academic search engines (Web of Science, PubMed, ProQuest, Scopus, and Google Scholar) were searched for literature on T. trichiura prevalence in Asia published through January 2021. Pooled prevalence was determined using the meta-package in R (version 3.6.1). Out of 13,836 articles, 226 studies (5,439,500 individuals) from 26 countries met the inclusion criteria. Of the 226 studies, 151 were community-based studies that included individuals across the age spectrum, while 75 studies focused on school children (typically in the 5-16 years age range). The overall T. trichiura pooled prevalence was 15.3% (95% CI: 12.4-19.1%), with a pooled prevalence of 13.3% (95% CI: 10.0-17.1%) for the community studies and 20.9% (95% CI: 14.7-27.9%) for the studies only including school children. For studies including all age groups, individuals in the 1-15 years age group had the highest pooled prevalence at 23.4% (95% CI: 1.7-49.4%). There was a significant difference found in overall pooled prevalence by sex (p < 0.001) and community type (rural versus urban) (p < 0.001). Although prevalence appears to be decreasing, study findings suggest that T. trichiura infection continues to be a public health problem in Asia. Therefore, control programs focused on at-risk individuals in endemic areas are needed.
Topics: Adolescent; Animals; Ascariasis; Ascaris lumbricoides; Asia; Child; Child, Preschool; Feces; Helminthiasis; Humans; Infant; Prevalence; Sanitation; Soil; Trichuriasis; Trichuris
PubMed: 34993634
DOI: 10.1007/s00436-021-07365-8 -
PLoS Neglected Tropical Diseases Oct 2022Soil-transmitted helminths (STH) infect 1.5 billion people and countless animals worldwide. In Australian Indigenous communities, STH infections have largely remained... (Meta-Analysis)
Meta-Analysis
Soil-transmitted helminths (STH) infect 1.5 billion people and countless animals worldwide. In Australian Indigenous communities, STH infections have largely remained endemic despite control efforts, suggesting reservoirs of infection may exist. Dogs fulfil various important cultural, social and occupational roles in Australian Indigenous communities and are populous in these settings. Dogs may also harbour zoonotic STHs capable of producing morbidity and mortality in dogs and humans. This review provides an overview of human and zoonotic STH infections, identifies the Australian Indigenous locations affected and the parasite species and hosts involved. The meta-analysis provides estimates of individual study and pooled true prevalence of STH infections in Australian Indigenous communities and identifies knowledge gaps for further research on zoonotic or anthroponotic potential. A systematic literature search identified 45 eligible studies documenting the presence of Strongyloides stercoralis, Trichuris trichiura, Ancylostoma caninum, Ancylostoma duodenale, Ancylostoma ceylanicum, undifferentiated hookworm, and Ascaris lumbricoides. Of these studies, 26 were also eligible for inclusion in meta-analysis to establish true prevalence in the light of imperfect diagnostic test sensitivity and specificity by Rogan-Gladen and Bayesian methods. These studies revealed pooled true prevalence estimates of 18.9% (95% CI 15.8-22.1) for human and canine S. stercoralis infections and 77.3% (95% CI 63.7-91.0) for canine A. caninum infections indicating continued endemicity, but considerably more heterogenous pooled estimates for canine A. ceylanicum infections, and A. duodenale, undifferentiated hookworm and T. trichiura in humans. This review suggests that the prevalence of STHs in Australian Indigenous communities has likely been underestimated, principally based on imperfect diagnostic tests. Potential misclassification of hookworm species in humans and dogs due to outdated methodology, also obscures this picture. High-quality contemporary studies are required to establish current true prevalence of parasite species in all relevant hosts to guide future policy development and control decisions under a culturally sound One Health framework.
Topics: Humans; Dogs; Animals; Soil; Bayes Theorem; Australia; Helminths; Ascaris lumbricoides; Trichuris; Helminthiasis; Hookworm Infections; Ancylostomatoidea; Ancylostoma; Zoonoses; Prevalence; Feces
PubMed: 36279298
DOI: 10.1371/journal.pntd.0010895 -
The Cochrane Database of Systematic... Apr 2020Ascaris lumbricoides is a common infection, and mainly affects children living in low-income areas. Water and sanitation improvement, health education, and drug... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Ascaris lumbricoides is a common infection, and mainly affects children living in low-income areas. Water and sanitation improvement, health education, and drug treatment may help break the cycle of transmission, and effective drugs will reduce morbidity.
OBJECTIVES
To compare the efficacy and safety of anthelmintic drugs (albendazole, mebendazole, ivermectin) for treating people with Ascaris infection.
SEARCH METHODS
We searched the Cochrane Infectious Disease Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, three other databases, and reference lists of included studies, without language restrictions, up to 4 July 2019.
SELECTION CRITERIA
Randomized controlled trials (RCT) that compared albendazole, mebendazole, and ivermectin in children and adults with confirmed Ascaris infection.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed studies for inclusion, assessed risk of bias, and extracted data from the included trials. A third review author checked the quality of data extraction. We used the Cochrane 'Risk of bias' assessment tool to determine the risk of bias in included trials. We used risk ratios (RRs) with 95% confidence intervals (CIs) to compare dichotomous outcomes in treatment and control groups. We used the fixed-effect model for studies with low heterogeneity and the random-effects model for studies with moderate to high heterogeneity. We assessed the certainty of the evidence using the GRADE approach. We used the control rate average to provide illustrative cure rates in the comparison groups.
MAIN RESULTS
We included 30 parallel-group RCTs, which enrolled 6442 participants from 17 countries across Africa, Asia, Central America and the Caribbean, and South America. Participants were from 28 days to 82 years of age, recruited from school, communities, and health facilities. Twenty studies were funded or co-funded by manufacturers, while 10 studies were independent of manufacturer funding. Twenty-two trials had a high risk of bias for one or two domains (blinding, incomplete outcome data, selective reporting). Single dose of albendazole (four trials), mebendazole (three trials) or ivermectin (one trial) was compared to placebo. Parasitological cure at 14 to 60 days was high in all the studies (illustrative cure of 93.0% in the anthelmintic group and 16.1% in the placebo group; RR 6.29, 95% CI 3.91 to 10.12; 8 trials, 1578 participants; moderate-certainty evidence). Single dose of albendazole is as effective as multiple doses of albendazole (illustrative cure of 93.2% with single dose, 94.3% with multiple doses; RR 0.98, 95% CI 0.92 to 1.05; 3 trials, 307 participants; high-certainty evidence); or as single dose of mebendazole (illustrative cure of 98.0% with albendazole, 96.9% with mebendazole; RR 1.01, 95% CI 1.00 to 1.02; 6 trials, 2131 participants; high-certainty evidence). Studies did not detect a difference between a single dose of albendazole and a single dose of ivermectin (cure rates of 87.8% with albendazole, 90.2% with ivermectin; RR 0.99, 95% CI 0.91 to 1.08; 3 trials, 519 participants; moderate-certainty evidence). Across all the studies, failure after single dose of albendazole ranged from 0.0% to 30.3%, mebendazole from 0.0% to 22.2%, and ivermectin from 0.0% to 21.6%. The egg reduction rate (ERR) measured up to 60 days after the treatment was high in all treated groups, regardless of the anthelmintic used (range 96% to 100%). It was not possible to evaluate parasitological cure by classes of infection intensity. No included trials reported complication or serious adverse events. Other adverse events were apparently similar among the compared anthelmintic groups (moderate- to low-certainty evidence). The most commonly reported other adverse events were nausea, vomiting, abdominal pain, diarrhoea, headache, and fever.
AUTHORS' CONCLUSIONS
Single-dose of albendazole, mebendazole, and ivermectin all appeared effective against Ascaris lumbricoides infection, yielding high parasitological cure and large reductions in eggs excreted, with no differences detected between them. The drugs appear to be safe to treat children and adults with confirmed Ascaris infection. There is little to choose between drugs and regimens in terms of cure or adverse events.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Albendazole; Animals; Anthelmintics; Ascariasis; Ascaris lumbricoides; Child; Child, Preschool; Humans; Infant; Ivermectin; Mebendazole; Middle Aged; Parasite Egg Count; Placebos; Randomized Controlled Trials as Topic; Young Adult
PubMed: 32289194
DOI: 10.1002/14651858.CD010599.pub2